Journal of Changsha University of Science & Technology (Natural Science)
Volume 22,2025 Issue 6
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- Detection of earthquake-induced cracks in masonry structures based ondual attention U-Net
- Research on voltage-current characteristics and electrothermal characteristics of multiphase composite conductive asphalt mixtures
- Research on rheological and fatigue properties of ball-milled GNPs/SiO2 composite modified asphalt
- Study on evaporation of Dongting Lake during dry season based on hydrogen and oxygen isotopes
- Current status of resource utilization technologies for dredged sludges in rivers and lakes and their applications
- Research progress of pedestrian-ground contact injuries in pedestrian-vehicle collision accident
- Review of principles and research on noise reduction technology fordense-graded rubber asphalt pavements
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- Inundation characteristics of typhoon-induced rainfall in Zhuhai based on Sentinel-1A SAR images
- Research progress of real-time acquisition technologies for surrounding rock characteristics of shield tunnels
- Analysis of water level variations during dry season and its impact on water supply of gate-pump system in northern Dongting Lake
- Review on solid hydrogen storage properties and basic improving methods
- Phase change energy storage technology and its application in the integration of transportation and energy
- Current status and prospects of integrated development oftransportation and energy
- Experimental study on mechanical properties of inherent anisotropy sand under pure principal stress rotation
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2025,22(6):1-10
,DOI: 10.19951/j.cnki.1672-9331.20250828003
Abstract:
［Purposes ］ In order to achieve sustainable development，industrial solid wastes （red mud，carbide slag，and slag） were used to prepare cementitious materials as a binder for semi -rigid base and develop red sandy soil stabilized by full -solid waste alkali -activated cementitious materials （FSCMS）.［Methods］ The unconfined compressive strength，indirect tensile strength，and water stability were investigated under different dosages （mass fraction ） of binder，and the strength formation mechanism was analyzed by X -ray diffraction，Fourier transform infrared spectroscopy，and scanning electron microscope tests.［Findings］ When the dosage of binder ranged from 0% to 20%，the pavement performance of FSCMS increased as the dosage of binder increased.When the dosage of binder was 20%，the 7 d unconfined compressive strength and indirect tensile strength of FSCMS reached 2.1 MPa and 0.37 MPa，respectively，and the water stability coefficient reached 0.67，which fulfilled the requirements of high -grade highway for lime fly ash base materials.Red mud，carbide slag，and slag underwent alkali -activated reactions in the soil environment to generate calcium aluminosilicate hydrate （C-A-S-H） gels，which significantly enhanced the performance of FSCMS through pore filling and chemical cementation.［Conclusions ］ The application of full -solid waste alkali -activated materials for semi -rigid base is feasible，and the research provides a theoretical foundation and technical guidance for the utilization of industrial solid wastes in pavement engineering.
［Purposes ］ In order to achieve sustainable development，industrial solid wastes （red mud，carbide slag，and slag） were used to prepare cementitious materials as a binder for semi -rigid base and develop red sandy soil stabilized by full -solid waste alkali -activated cementitious materials （FSCMS）.［Methods］ The unconfined compressive strength，indirect tensile strength，and water stability were investigated under different dosages （mass fraction ） of binder，and the strength formation mechanism was analyzed by X -ray diffraction，Fourier transform infrared spectroscopy，and scanning electron microscope tests.［Findings］ When the dosage of binder ranged from 0% to 20%，the pavement performance of FSCMS increased as the dosage of binder increased.When the dosage of binder was 20%，the 7 d unconfined compressive strength and indirect tensile strength of FSCMS reached 2.1 MPa and 0.37 MPa，respectively，and the water stability coefficient reached 0.67，which fulfilled the requirements of high -grade highway for lime fly ash base materials.Red mud，carbide slag，and slag underwent alkali -activated reactions in the soil environment to generate calcium aluminosilicate hydrate （C-A-S-H） gels，which significantly enhanced the performance of FSCMS through pore filling and chemical cementation.［Conclusions ］ The application of full -solid waste alkali -activated materials for semi -rigid base is feasible，and the research provides a theoretical foundation and technical guidance for the utilization of industrial solid wastes in pavement engineering.
2025,22(6):11-20
,DOI: 10.19951/j.cnki.1672-9331.20250828004
Abstract:
［Purposes ］ This study investigated the effect of carbonation modification on the stability of steel slag and examined its application performance，aiming to provide a reference for the use of steel slag as a solid waste material in artificial reef construction.［Methods］ Steel slag powder was treated via microwave -assisted carbonation and conventional carbonation.The effects of these two carbonation methods on the stability and mechanical properties of steel slag powder were compared and analyzed.Furthermore，the influence of varying steel slag powder dosages （mass fractions） was studied in a ternary solid waste -based cementitious system （comprising steel slag，mineral powder，and desulfurization gypsum ） as well as in artificial reef concrete.［Findings］ Microwave -assisted carbonation activated and modified the steel slag powder effectively.When the carbonated steel slag content was 30.00%，desulfurization gypsum 10.00%，and mineral powder 60.00%，the 28-day compressive strength of the ternary cementitious system reached 20.74 MPa，meeting the C 20 strength requirement for artificial reefs.［Conclusions ］ Microwave -assisted carbonation significantly reduced the free CaO content in steel slag，improved its stability，and enhanced the early strength and durability of the cementitious system.Carbonated steel slag -based materials demonstrated excellent mechanical adaptability，cost -effectiveness，and environmental friendliness in artificial reef applications，offering a viable solution for low -carbon marine engineering and solid waste recycling.
［Purposes ］ This study investigated the effect of carbonation modification on the stability of steel slag and examined its application performance，aiming to provide a reference for the use of steel slag as a solid waste material in artificial reef construction.［Methods］ Steel slag powder was treated via microwave -assisted carbonation and conventional carbonation.The effects of these two carbonation methods on the stability and mechanical properties of steel slag powder were compared and analyzed.Furthermore，the influence of varying steel slag powder dosages （mass fractions） was studied in a ternary solid waste -based cementitious system （comprising steel slag，mineral powder，and desulfurization gypsum ） as well as in artificial reef concrete.［Findings］ Microwave -assisted carbonation activated and modified the steel slag powder effectively.When the carbonated steel slag content was 30.00%，desulfurization gypsum 10.00%，and mineral powder 60.00%，the 28-day compressive strength of the ternary cementitious system reached 20.74 MPa，meeting the C 20 strength requirement for artificial reefs.［Conclusions ］ Microwave -assisted carbonation significantly reduced the free CaO content in steel slag，improved its stability，and enhanced the early strength and durability of the cementitious system.Carbonated steel slag -based materials demonstrated excellent mechanical adaptability，cost -effectiveness，and environmental friendliness in artificial reef applications，offering a viable solution for low -carbon marine engineering and solid waste recycling.
2025,22(6):21-31
,DOI: 10.19951/j.cnki.1672-9331.20251014001
Abstract:
［Purposes ］ Natural aggregate resources are currently in short supply.Using epoxy resin and matrix asphalt to modify reclaimed asphalt pavement （RAP） is one way to promote the effective utilization of RAP.［Methods］ The water absorption and crushing values of modified RAP with thicknesses of 0.1 mm and 0.2 mm were investigated.Rapid freeze -thaw testing and uniaxial compression testing were conducted to evaluate the frost resistance and stress and strain characteristics of self -compacting concrete with modified RAP.［Findings］ Both epoxy resin and matrix asphalt modification can improve the water absorption and crushing value of RAP.The frost resistance of specimens with RAP and matrix asphalt -modified RAP outperforms that of self -compacting concrete specimens with epoxy resin -modified RAP.However，the frost resistance of self-compacting concrete specimens with epoxy resin -modified RAP meets the F 300 performance requirements.Under freeze -thaw cycles，the mechanical properties of self -compacting concrete specimens with epoxy resin -modified RAP are superior to those of self -compacting concrete specimens with RAP and matrix asphalt -modified RAP.Compared to that of self -compacting concrete specimens with RAP，the peak stress of self -compacting concrete specimens with 0.1 mm and 0.2 mm epoxy resin -modified RAP increases by 43.17% and 50.63% under 300 freeze -thaw cycles，respectively.［Conclusions ］ The findings of this study provide a novel approach and methodology for enhancing the mechanical properties of self -compacting concrete with RAP，effectively promoting the utilization of RAP.
［Purposes ］ Natural aggregate resources are currently in short supply.Using epoxy resin and matrix asphalt to modify reclaimed asphalt pavement （RAP） is one way to promote the effective utilization of RAP.［Methods］ The water absorption and crushing values of modified RAP with thicknesses of 0.1 mm and 0.2 mm were investigated.Rapid freeze -thaw testing and uniaxial compression testing were conducted to evaluate the frost resistance and stress and strain characteristics of self -compacting concrete with modified RAP.［Findings］ Both epoxy resin and matrix asphalt modification can improve the water absorption and crushing value of RAP.The frost resistance of specimens with RAP and matrix asphalt -modified RAP outperforms that of self -compacting concrete specimens with epoxy resin -modified RAP.However，the frost resistance of self-compacting concrete specimens with epoxy resin -modified RAP meets the F 300 performance requirements.Under freeze -thaw cycles，the mechanical properties of self -compacting concrete specimens with epoxy resin -modified RAP are superior to those of self -compacting concrete specimens with RAP and matrix asphalt -modified RAP.Compared to that of self -compacting concrete specimens with RAP，the peak stress of self -compacting concrete specimens with 0.1 mm and 0.2 mm epoxy resin -modified RAP increases by 43.17% and 50.63% under 300 freeze -thaw cycles，respectively.［Conclusions ］ The findings of this study provide a novel approach and methodology for enhancing the mechanical properties of self -compacting concrete with RAP，effectively promoting the utilization of RAP.
2025,22(6):32-45
,DOI: 10.19951/j.cnki.1672-9331.20251111001
Abstract:
［Purposes ］ This paper aims to enhance the activity of waste ceramic powder （WCP） and evaluate its applicability in cement -stabilized macadam （CSM） base.［Methods］ The physical and chemical activation methods were adopted to improve the activity of WCP.The activated WCP was used to partially substitute cement，and the effects of physical and chemical activation methods on the flowability and setting time of the WCP cementitious material were analyzed.Then，the WCP cement mortar and WCP -CSM were prepared，and their mechanical properties were analyzed.［Findings］ The incorporation of WCP reduced mortar flowability and prolonged setting time，while physical and chemical activation methods accelerated the hydration process and shortened the setting time of the mortar.When physically and chemically activated WCP was employed，both the compressive and flexural strengths of the mortar were enhanced.However，the strengths of chemically activated cement mortar were significantly greater than those of physically activated cement mortar.When the content of WCP was 15%；the water -binder ratio was 0.4，and the curing age was 28 days，the compressive and flexural strengths of the physically activated mortar improved by 1.5% and 1.1%，respectively，compared to the original cement mortar；the compressive and flexural strengths of the chemically activated mortar improved by 4.5% and 2.2%，respectively.When the content of WCP ranged from 5% to less than 15%，physical activation was more suitable for finer WCP.At a content of 15%-20%，chemical activation exhibited superior effects，but the activator concentration must be appropriately controlled.Moreover，the density of WCP -CSM could be improved by the physical activation method.Although the structure of WCP -CSM could be improved by the chemical activation method，its pore size will be slightly increased.Meanwhile，physically activated WCP provided moderate improvement in the mechanical properties of CSM，whereas chemically activated WCP yielded more pronounced effects.When the content of cement was 6%，the unconfined compressive strength of the mixture with physical activation increased by 0.16 MPa，and the splitting tensile strength increased by 0.03 MPa after 90 days.The unconfined compressive strength of the mixture with chemical activation increased by 0.44 MPa，and the splitting tensile strength increased by 0.07 MPa after 90 days.The 7-day unconfined compressive strength of both physically and chemically activated WCP -CSM met the specifications of a cement -stabilized base layer for expressways.［Conclusions ］ After the physically and chemically activated WCP substitutes cement，the workability and mechanical properties of cement mortar and CSM are significantly improved，and the chemically activated WCP demonstrates better performance.This paper not only provides a reference for promoting solid waste utilization and finding alternative materials of cement but also offers a viable pathway for the choice of green and low -carbon materials of pavement base layers.
［Purposes ］ This paper aims to enhance the activity of waste ceramic powder （WCP） and evaluate its applicability in cement -stabilized macadam （CSM） base.［Methods］ The physical and chemical activation methods were adopted to improve the activity of WCP.The activated WCP was used to partially substitute cement，and the effects of physical and chemical activation methods on the flowability and setting time of the WCP cementitious material were analyzed.Then，the WCP cement mortar and WCP -CSM were prepared，and their mechanical properties were analyzed.［Findings］ The incorporation of WCP reduced mortar flowability and prolonged setting time，while physical and chemical activation methods accelerated the hydration process and shortened the setting time of the mortar.When physically and chemically activated WCP was employed，both the compressive and flexural strengths of the mortar were enhanced.However，the strengths of chemically activated cement mortar were significantly greater than those of physically activated cement mortar.When the content of WCP was 15%；the water -binder ratio was 0.4，and the curing age was 28 days，the compressive and flexural strengths of the physically activated mortar improved by 1.5% and 1.1%，respectively，compared to the original cement mortar；the compressive and flexural strengths of the chemically activated mortar improved by 4.5% and 2.2%，respectively.When the content of WCP ranged from 5% to less than 15%，physical activation was more suitable for finer WCP.At a content of 15%-20%，chemical activation exhibited superior effects，but the activator concentration must be appropriately controlled.Moreover，the density of WCP -CSM could be improved by the physical activation method.Although the structure of WCP -CSM could be improved by the chemical activation method，its pore size will be slightly increased.Meanwhile，physically activated WCP provided moderate improvement in the mechanical properties of CSM，whereas chemically activated WCP yielded more pronounced effects.When the content of cement was 6%，the unconfined compressive strength of the mixture with physical activation increased by 0.16 MPa，and the splitting tensile strength increased by 0.03 MPa after 90 days.The unconfined compressive strength of the mixture with chemical activation increased by 0.44 MPa，and the splitting tensile strength increased by 0.07 MPa after 90 days.The 7-day unconfined compressive strength of both physically and chemically activated WCP -CSM met the specifications of a cement -stabilized base layer for expressways.［Conclusions ］ After the physically and chemically activated WCP substitutes cement，the workability and mechanical properties of cement mortar and CSM are significantly improved，and the chemically activated WCP demonstrates better performance.This paper not only provides a reference for promoting solid waste utilization and finding alternative materials of cement but also offers a viable pathway for the choice of green and low -carbon materials of pavement base layers.
2025,22(6):46-58
,DOI: 10.19951/j.cnki.1672-9331.20250814001
Abstract:
［Purposes ］ Non -destructive detection of structural cracks in expressway pavement is a crucial link in supporting road maintenance and traffic operation safety.Although detection methods based on ground -penetrating radar （GPR） images and deep neural networks have achieved certain results，there are still deficiencies in terms of accuracy and stability.Therefore，this paper optimized the intelligent detection performance of GPR and focused on addressing the issues of accuracy and stability in detecting structural cracks in pavement，providing technical support for road maintenance.［Methods］ A three -dimensional detection method for structural cracks in pavement based on the sparse deep network of electric field intensity was proposed，namely sparse convolutional GPR detection network.Firstly，this method directly took the three -dimensional electric field intensity distribution of GPR as input and converted it into a three -dimensional voxel tensor.Then，the three -dimensional voxel tensor was successively processed by the SparseNorm module，Dual module，and Tri module to extract the structural crack features in pavement from the electric field intensity distribution.Finally，the structural crack features in pavement were input into the separated detection head to predict the three -dimensional bounding box of the structural crack in pavement.［Findings］ The experimental results on three expressways show that the average precision rates of the detection method at thresholds of 0.3 and 0.5 are 0.831 and 0.463，respectively，and its accuracy and stability are both better than those of the image detection network.［Conclusions ］ The sparse deep neural network with the electric field intensity distribution of GPR as input provides a high -precision automatic method for non -destructive detection of structural cracks in expressway pavement.
［Purposes ］ Non -destructive detection of structural cracks in expressway pavement is a crucial link in supporting road maintenance and traffic operation safety.Although detection methods based on ground -penetrating radar （GPR） images and deep neural networks have achieved certain results，there are still deficiencies in terms of accuracy and stability.Therefore，this paper optimized the intelligent detection performance of GPR and focused on addressing the issues of accuracy and stability in detecting structural cracks in pavement，providing technical support for road maintenance.［Methods］ A three -dimensional detection method for structural cracks in pavement based on the sparse deep network of electric field intensity was proposed，namely sparse convolutional GPR detection network.Firstly，this method directly took the three -dimensional electric field intensity distribution of GPR as input and converted it into a three -dimensional voxel tensor.Then，the three -dimensional voxel tensor was successively processed by the SparseNorm module，Dual module，and Tri module to extract the structural crack features in pavement from the electric field intensity distribution.Finally，the structural crack features in pavement were input into the separated detection head to predict the three -dimensional bounding box of the structural crack in pavement.［Findings］ The experimental results on three expressways show that the average precision rates of the detection method at thresholds of 0.3 and 0.5 are 0.831 and 0.463，respectively，and its accuracy and stability are both better than those of the image detection network.［Conclusions ］ The sparse deep neural network with the electric field intensity distribution of GPR as input provides a high -precision automatic method for non -destructive detection of structural cracks in expressway pavement.
2025,22(6):59-73
,DOI: 10.19951/j.cnki.1672-9331.20250905001
Abstract:
［Purposes ］ This paper aims to unveil the evolution patterns of asphalt pavement surface texture and skid resistance under vehicular loading.［Methods］ The plate specimens of modified asphalt mixture with three typical gradations in the surface layer of AC -13C （continuous gradation），SMA -13 （gap gradation ），and PA -13 （open gradation ） were prepared.The small -scale accelerated loading test system was used to simulate the long -term wear effect of driving load on asphalt pavement.The dynamic evolution processes of surface texture and skid resistance for asphalt mixtures were analyzed by using three -dimensional laser scanning technology combined with traditional skid resistance test methods.［Findings］ With the increase of wear times，the surface texture parameters such as arithmetic mean height，skewness，kurtosis，root mean square gradient，peak density，reduced peak height，and reduced valley depth show overall downward trends，while the fastest decay autocorrelation length and arithmetic mean peak curvature display upward trends，indicating that the surface texture of asphalt mixtures gradually evolves to homogenization under wheel load wear.Meanwhile，the surface mean texture depth of the asphalt mixtures shows a trend of continuous decelerating decay in the negative exponential function and tends to be stable gradually，while the British pendulum number shows a three -stage change of rapid decay，short -term recovery，and stable decay.The short -term recovery is caused by the surface texture reconstruction due to the wear of the surface asphalt film.The skid resistance durability of the three asphalt mixtures is obviously different，and the long -term skid resistance of SMA -13 is the best.Based on the strong correlation texture parameters including arithmetic mean height，arithmetic mean peak curvature，peak density，and root mean square gradient，the multiple linear regression prediction models for the mean texture depth and the British pendulum number are established.The adjusted determination coefficients are more than 0.8，showing significant correlations.［Conclusions ］ The research results can provide a reliable reference for the design，construction，maintenance management，and accurate prediction of skid resistance in asphalt pavement.
［Purposes ］ This paper aims to unveil the evolution patterns of asphalt pavement surface texture and skid resistance under vehicular loading.［Methods］ The plate specimens of modified asphalt mixture with three typical gradations in the surface layer of AC -13C （continuous gradation），SMA -13 （gap gradation ），and PA -13 （open gradation ） were prepared.The small -scale accelerated loading test system was used to simulate the long -term wear effect of driving load on asphalt pavement.The dynamic evolution processes of surface texture and skid resistance for asphalt mixtures were analyzed by using three -dimensional laser scanning technology combined with traditional skid resistance test methods.［Findings］ With the increase of wear times，the surface texture parameters such as arithmetic mean height，skewness，kurtosis，root mean square gradient，peak density，reduced peak height，and reduced valley depth show overall downward trends，while the fastest decay autocorrelation length and arithmetic mean peak curvature display upward trends，indicating that the surface texture of asphalt mixtures gradually evolves to homogenization under wheel load wear.Meanwhile，the surface mean texture depth of the asphalt mixtures shows a trend of continuous decelerating decay in the negative exponential function and tends to be stable gradually，while the British pendulum number shows a three -stage change of rapid decay，short -term recovery，and stable decay.The short -term recovery is caused by the surface texture reconstruction due to the wear of the surface asphalt film.The skid resistance durability of the three asphalt mixtures is obviously different，and the long -term skid resistance of SMA -13 is the best.Based on the strong correlation texture parameters including arithmetic mean height，arithmetic mean peak curvature，peak density，and root mean square gradient，the multiple linear regression prediction models for the mean texture depth and the British pendulum number are established.The adjusted determination coefficients are more than 0.8，showing significant correlations.［Conclusions ］ The research results can provide a reliable reference for the design，construction，maintenance management，and accurate prediction of skid resistance in asphalt pavement.
2025,22(6):74-88
,DOI: 10.19951/j.cnki.1672-9331.20250730001
Abstract:
［Purposes ］ The research on the influence of filler with a low freezing point on rheological properties of modified asphalt mastic remains immature，limiting performance improvement in asphalt pavement with a low freezing point.This study aims to investigate the rheological property patterns of modified asphalt mastic with a low freezing point，providing theoretical guidance for the practical engineering application of asphalt mixtures with a low freezing point.［Methods］ This study used filler with a low freezing point to replace mineral powder based on the equal volume replacement method and prepared modified asphalt mastic with a low freezing point at powder -to-binder ratios of 0.8，1.0，and 1.2，respectively.Subsequently，the asphalt mastic was tested for viscoelasticity，high -temperature property，fatigue damage resistance，and low-temperature cracking resistance.［Findings］ The viscoelasticity，high -temperature property，and fatigue damage resistance of modified asphalt mastic with a low freezing point improve gradually with the increase of powder -to-binder ratio，but the presence of filler with a low freezing point degrades the low -temperature cracking resistance of asphalt mastic.The rheological properties of modified asphalt mastic with a low freezing point are jointly affected by the type of matrix asphalt，the type of modifier，and its dosage.At a powder -to-binder ratio of 1.2，the asphalt mastic prepared with 90# asphalt and 3% SBS star -shaped modifier exhibits a fracture deflection at ?12 ℃ that is 1.21 times greater than that of the mastic prepared with 70# asphalt and 3% SBS star-shaped modifier.However，its rutting factor at 60 ℃ is only 77% of the latter ’s value.The rheological properties of modified asphalt mastic improve with the increase of modifier dosage，but they are relatively less affected by the modifier type.［Conclusions ］ Fillers with a low freezing point can enhance the high -temperature stability and fatigue resistance of modified asphalt mastic，but this must be balanced against their negative impact on low -temperature cracking resistance.In practical engineering applications，the type of matrix asphalt，the dosage of modifiers，and the proportion of fillers with a low freezing point should be selected reasonably based on climatic conditions and road performance requirements to achieve the balanced optimization of the comprehensive performance of asphalt mastic with a low freezing point.
［Purposes ］ The research on the influence of filler with a low freezing point on rheological properties of modified asphalt mastic remains immature，limiting performance improvement in asphalt pavement with a low freezing point.This study aims to investigate the rheological property patterns of modified asphalt mastic with a low freezing point，providing theoretical guidance for the practical engineering application of asphalt mixtures with a low freezing point.［Methods］ This study used filler with a low freezing point to replace mineral powder based on the equal volume replacement method and prepared modified asphalt mastic with a low freezing point at powder -to-binder ratios of 0.8，1.0，and 1.2，respectively.Subsequently，the asphalt mastic was tested for viscoelasticity，high -temperature property，fatigue damage resistance，and low-temperature cracking resistance.［Findings］ The viscoelasticity，high -temperature property，and fatigue damage resistance of modified asphalt mastic with a low freezing point improve gradually with the increase of powder -to-binder ratio，but the presence of filler with a low freezing point degrades the low -temperature cracking resistance of asphalt mastic.The rheological properties of modified asphalt mastic with a low freezing point are jointly affected by the type of matrix asphalt，the type of modifier，and its dosage.At a powder -to-binder ratio of 1.2，the asphalt mastic prepared with 90# asphalt and 3% SBS star -shaped modifier exhibits a fracture deflection at ?12 ℃ that is 1.21 times greater than that of the mastic prepared with 70# asphalt and 3% SBS star-shaped modifier.However，its rutting factor at 60 ℃ is only 77% of the latter ’s value.The rheological properties of modified asphalt mastic improve with the increase of modifier dosage，but they are relatively less affected by the modifier type.［Conclusions ］ Fillers with a low freezing point can enhance the high -temperature stability and fatigue resistance of modified asphalt mastic，but this must be balanced against their negative impact on low -temperature cracking resistance.In practical engineering applications，the type of matrix asphalt，the dosage of modifiers，and the proportion of fillers with a low freezing point should be selected reasonably based on climatic conditions and road performance requirements to achieve the balanced optimization of the comprehensive performance of asphalt mastic with a low freezing point.
2025,22(6):89-100
,DOI: 10.19951/j.cnki.1672-9331.20250728001
Abstract:
［Purposes ］ To address challenges such as sudden regional load surges，sensitive terminal energy consumption，and significant increases in ineffective carbon emissions during high -concurrency scenarios in power mobile applications，this study aims to overcome the limitations of traditional resource scheduling models in dynamic prediction，elastic scaling，and energy efficiency optimization.［Methods］ An elastic green optimization framework for agent collaboration was proposed.1） It employed a lightweight spatio -temporal convolutional neural network that integrated power work order priority and disaster factors to achieve 15-minute -level load prediction.2） It established a multi -agent collaborative mechanism featuring “monitoring，scheduling，and energy efficiency ”，dynamically balancing delay and carbon emission targets through dynamic weighting functions.3） It designed a joint optimization model for end -cloud energy efficiency，integrating a power usage effectiveness （PUE） hierarchical deployment mechanism，a terminal energy consumption -aware scheduling module，and retry suppression middleware，solving the coupling optimization problem of energy consumption sensitivity on mobile sides and energy efficiency of cloud resources.［Findings］ The proposed method was validated under million -level concurrency in provincial power grids，reducing the service level agreement collapse rate to 4.7% during disaster periods，lowering the average energy consumption per request for legacy terminals to 0.81 J，and optimizing the data center PUE to 1.22.［Conclusions ］ This framework offers a novel resource scheduling solution for power mobile services characterized by “elastic responsiveness ” and “green operation and low carbon emissions ”，and it provides effective technical support for achieving the “energy conservation and emission reduction ” goals，as well as for realizing the “carbon peaking and carbon neutrality ” goals and the digital construction of the new power system.
［Purposes ］ To address challenges such as sudden regional load surges，sensitive terminal energy consumption，and significant increases in ineffective carbon emissions during high -concurrency scenarios in power mobile applications，this study aims to overcome the limitations of traditional resource scheduling models in dynamic prediction，elastic scaling，and energy efficiency optimization.［Methods］ An elastic green optimization framework for agent collaboration was proposed.1） It employed a lightweight spatio -temporal convolutional neural network that integrated power work order priority and disaster factors to achieve 15-minute -level load prediction.2） It established a multi -agent collaborative mechanism featuring “monitoring，scheduling，and energy efficiency ”，dynamically balancing delay and carbon emission targets through dynamic weighting functions.3） It designed a joint optimization model for end -cloud energy efficiency，integrating a power usage effectiveness （PUE） hierarchical deployment mechanism，a terminal energy consumption -aware scheduling module，and retry suppression middleware，solving the coupling optimization problem of energy consumption sensitivity on mobile sides and energy efficiency of cloud resources.［Findings］ The proposed method was validated under million -level concurrency in provincial power grids，reducing the service level agreement collapse rate to 4.7% during disaster periods，lowering the average energy consumption per request for legacy terminals to 0.81 J，and optimizing the data center PUE to 1.22.［Conclusions ］ This framework offers a novel resource scheduling solution for power mobile services characterized by “elastic responsiveness ” and “green operation and low carbon emissions ”，and it provides effective technical support for achieving the “energy conservation and emission reduction ” goals，as well as for realizing the “carbon peaking and carbon neutrality ” goals and the digital construction of the new power system.
2025,22(6):101-109
,DOI: 10.19951/j.cnki.1672-9331.20250512001
Abstract:
Proton exchange membrane fuel cells （PEMFCs），known for their high efficiency and clean energy output，are emerging as an important carrier in hydrogen energy applications.They are widely used in transportation，power generation，and energy storage sectors.However，inadequate management of the heat produced during operation can result in reduced performance and a shorter service life.This paper systematically reviewed recent advances in the thermal management of PEMFCs，with a focus on three main cooling strategies：passive cooling，liquid cooling，and air cooling.It discussed their working principles，advantages，and suitable application scenarios.Furthermore，the paper delved into the latest developments in cooling channel design，control strategies，and novel structural materials，analyzing their potential to enhance thermal uniformity，energy efficiency，and system integration.Research indicates that optimizing channel designs，implementing intelligent control algorithms，and developing advanced cooling components are critical pathways to improve hermal management of PEMFCs.The paper outlines future trends toward more efficient，intelligent，and integrated thermal management technologies，aiming to provide theoretical support and technical guidance for the engineering application of PEMFCs.
Proton exchange membrane fuel cells （PEMFCs），known for their high efficiency and clean energy output，are emerging as an important carrier in hydrogen energy applications.They are widely used in transportation，power generation，and energy storage sectors.However，inadequate management of the heat produced during operation can result in reduced performance and a shorter service life.This paper systematically reviewed recent advances in the thermal management of PEMFCs，with a focus on three main cooling strategies：passive cooling，liquid cooling，and air cooling.It discussed their working principles，advantages，and suitable application scenarios.Furthermore，the paper delved into the latest developments in cooling channel design，control strategies，and novel structural materials，analyzing their potential to enhance thermal uniformity，energy efficiency，and system integration.Research indicates that optimizing channel designs，implementing intelligent control algorithms，and developing advanced cooling components are critical pathways to improve hermal management of PEMFCs.The paper outlines future trends toward more efficient，intelligent，and integrated thermal management technologies，aiming to provide theoretical support and technical guidance for the engineering application of PEMFCs.
2025,22(6):110-121
,DOI: 10.19951/j.cnki.1672-9331.20250531001
Abstract:
［Purposes ］ To address the demand for efficient wind energy utilization in low -wind -speed regions，this study took the three -dimensional array configuration of Savonius wind turbines adapted for low -wind -speed environments as its research object.It conducted a multi -parameter optimization design，aiming to enhance their overall wind energy utilization efficiency.［Methods］ The three -dimensional computational fluid dynamics （CFD） simulation method was combined with the Taguchi experimental design method to systematically analyze the effects of five parameters，namely horizontal spacing，horizontal included angle，vertical spacing，rotational direction，and initial phase angle，on the average power coefficient of the dual wind turbine system.［Findings］ Vertical spacing exerts the most significant regulatory effect on the system ’s power coefficient，followed by the rotational direction，horizontal included angle，initial phase angle，and horizontal spacing.The theoretically optimal parameter array configuration identified through multi -parameter optimization enables the system to achieve an average power coefficient of 0.177，representing a 6.5% enhancement compared to a single wind turbine.Flow field analysis reveals that the synergistic interaction between vertical spacing and the counter -rotating mode can attenuate wake interference，accelerate momentum recovery，suppress the growth of turbulent kinetic energy in the negative torque region，enhance the positive torque driving effect，and thereby improve the overall wind energy utilization efficiency.［Conclusions ］ The proposed three -dimensional array configuration of Savonius wind turbines enhances system stability and reduces the impact of variable wind direction on the system ’s power coefficient through the synergistic regulation of coupling effects between vertical spacing and other parameters.By efficiently utilizing vertical space，it significantly expands the wind -capturing area.This array configuration thus provides robust technical support for clean energy planning and power system layout in practical low -wind -speed regions.
［Purposes ］ To address the demand for efficient wind energy utilization in low -wind -speed regions，this study took the three -dimensional array configuration of Savonius wind turbines adapted for low -wind -speed environments as its research object.It conducted a multi -parameter optimization design，aiming to enhance their overall wind energy utilization efficiency.［Methods］ The three -dimensional computational fluid dynamics （CFD） simulation method was combined with the Taguchi experimental design method to systematically analyze the effects of five parameters，namely horizontal spacing，horizontal included angle，vertical spacing，rotational direction，and initial phase angle，on the average power coefficient of the dual wind turbine system.［Findings］ Vertical spacing exerts the most significant regulatory effect on the system ’s power coefficient，followed by the rotational direction，horizontal included angle，initial phase angle，and horizontal spacing.The theoretically optimal parameter array configuration identified through multi -parameter optimization enables the system to achieve an average power coefficient of 0.177，representing a 6.5% enhancement compared to a single wind turbine.Flow field analysis reveals that the synergistic interaction between vertical spacing and the counter -rotating mode can attenuate wake interference，accelerate momentum recovery，suppress the growth of turbulent kinetic energy in the negative torque region，enhance the positive torque driving effect，and thereby improve the overall wind energy utilization efficiency.［Conclusions ］ The proposed three -dimensional array configuration of Savonius wind turbines enhances system stability and reduces the impact of variable wind direction on the system ’s power coefficient through the synergistic regulation of coupling effects between vertical spacing and other parameters.By efficiently utilizing vertical space，it significantly expands the wind -capturing area.This array configuration thus provides robust technical support for clean energy planning and power system layout in practical low -wind -speed regions.
2025,22(6):122-131
,DOI: 10.19951/j.cnki.1672-9331.20250413001
Abstract:
［Purposes ］ Existing interval -based network optimization methods ignore time -dependent impedance variations，potentially resulting in excessively wide trip time intervals and methodological invalidity.This paper considered the interval uncertainty of time -dependent impedance and proposed a robust optimization model for trips based on time -limited arrival.［Methods］ Guided by the robust deviation principle and the limitations of conventional two -stage modeling，this paper proposed a single robust optimization model construction method to reduce computational complexity and enhance efficiency.First，a mixed -integer programming model for trips under time -dependent fixed impedance was developed based on time -limited arrival，aiming to minimize the latest departure time.Key constraints include time propagation，time connection，time consistency，and flow conservation.The corresponding dual model was derived.Second，the dual model was integrated with the trip optimization model to establish a minimum -maximum regret value optimization model for trips under time -dependent interval impedance based on time -limited arrival.［Findings］ Compared with the traditional optimization model using fixed interval impedance，the proposed model can significantly reduce the range of trip intervals.In the case study，both the trip time ranges and robust costs in the two road networks are reduced by approximately 50%，demonstrating the model ’s capability to enhance the reliability of optimization results.［Conclusions ］ By introducing the uncertainty of time interval impedance，the model proposed in this paper provides a more reliable trip optimization scheme for time -limited arrival scenarios，which has both theoretical significance and practical application value.
［Purposes ］ Existing interval -based network optimization methods ignore time -dependent impedance variations，potentially resulting in excessively wide trip time intervals and methodological invalidity.This paper considered the interval uncertainty of time -dependent impedance and proposed a robust optimization model for trips based on time -limited arrival.［Methods］ Guided by the robust deviation principle and the limitations of conventional two -stage modeling，this paper proposed a single robust optimization model construction method to reduce computational complexity and enhance efficiency.First，a mixed -integer programming model for trips under time -dependent fixed impedance was developed based on time -limited arrival，aiming to minimize the latest departure time.Key constraints include time propagation，time connection，time consistency，and flow conservation.The corresponding dual model was derived.Second，the dual model was integrated with the trip optimization model to establish a minimum -maximum regret value optimization model for trips under time -dependent interval impedance based on time -limited arrival.［Findings］ Compared with the traditional optimization model using fixed interval impedance，the proposed model can significantly reduce the range of trip intervals.In the case study，both the trip time ranges and robust costs in the two road networks are reduced by approximately 50%，demonstrating the model ’s capability to enhance the reliability of optimization results.［Conclusions ］ By introducing the uncertainty of time interval impedance，the model proposed in this paper provides a more reliable trip optimization scheme for time -limited arrival scenarios，which has both theoretical significance and practical application value.
2025,22(6):132-143
,DOI: 10.19951/j.cnki.1672-9331.20250409001
Abstract:
［Purposes ］ In response to the problem of uncertain passenger demand caused by subway line disruptions，a basic shuttle bus + supplementary shuttle bus approach was used to restore the system.［Methods］ Firstly，the uncertainty set was used to describe the fluctuation of origin -destination （OD） demand.To minimize the cumulative performance loss，the number of shuttle buses and passenger capacity were used as constraints，and a two -stage robust optimization -based shuttle bus scheduling model was constructed.Secondly，the column and constraint generation （C&CG） algorithm was used to solve the problem.Finally，experiments were conducted using Beijing Metro Line 14 and Line 12 as examples.［Findings］ The solution obtained by using the two -stage robust optimization model under uncertain demand scenarios can reduce 16.6% of cumulative performance loss and 14% of shuttle buses compared with the basic shuttle route solution and increase the service range by 20%；compared with the deterministic model，it reduces the performance loss by 6.3%，especially showing stronger adaptability and stability in harsh scenarios.［Conclusions ］ The two -stage robust optimization -based shuttle bus scheduling model proposed in this paper can effectively cope with the problem of passenger demand fluctuations caused by subway line disruptions and shows stronger robustness.
［Purposes ］ In response to the problem of uncertain passenger demand caused by subway line disruptions，a basic shuttle bus + supplementary shuttle bus approach was used to restore the system.［Methods］ Firstly，the uncertainty set was used to describe the fluctuation of origin -destination （OD） demand.To minimize the cumulative performance loss，the number of shuttle buses and passenger capacity were used as constraints，and a two -stage robust optimization -based shuttle bus scheduling model was constructed.Secondly，the column and constraint generation （C&CG） algorithm was used to solve the problem.Finally，experiments were conducted using Beijing Metro Line 14 and Line 12 as examples.［Findings］ The solution obtained by using the two -stage robust optimization model under uncertain demand scenarios can reduce 16.6% of cumulative performance loss and 14% of shuttle buses compared with the basic shuttle route solution and increase the service range by 20%；compared with the deterministic model，it reduces the performance loss by 6.3%，especially showing stronger adaptability and stability in harsh scenarios.［Conclusions ］ The two -stage robust optimization -based shuttle bus scheduling model proposed in this paper can effectively cope with the problem of passenger demand fluctuations caused by subway line disruptions and shows stronger robustness.
2025,22(6):144-164
,DOI: 10.19951/j.cnki.1672-9331.20250730002
Abstract:
In recent years，local scour of submarine pipelines has intensified，and there is an urgent need to ensure the safe and stable operation of pipelines.In this paper，recent achievements on the protection and remediation measures for local scour of submarine pipelines were reviewed and evaluated systematically.These measures could be categorized into three groups：active methods，passive methods，and self -burial promotion.Active methods are implemented by modifying the flow field and seepage field around pipelines，including floating flow-deflecting structures，rigid guide plates，bionic grass，permeable frame structures，and rigid protective plates.Active methods offer high flexibility and often combine sediment -promotion functions.However，as their sediment -promotion effect is constrained by upstream sediment supply，they are suitable for protecting newly laid pipelines and for remedying existing scour holes around in -service pipelines.Passive methods are implemented by enhancing the seabed soil ’s resistance to scouring and seepage -induced failure，including techniques such as riprap placement，sandbagging，flexible mattress installation，and soil improvement.Passive methods，while technically mature，involve high construction and maintenance costs and have significant environmental impacts.They are applicable for remedying pipeline spanning caused by geomorphic evolution and for emergency remediation of long -distance spanning.Promoting pipeline self -burial is achieved by accelerating the self -burial process，enabling the pipeline to be embedded in the seabed within a short period.This primarily includes methods such as spoilers.Once self -buried，the pipeline ’s risk of scour is significantly reduced.However，this approach imposes specific requirements on the local hydrodynamic conditions and seabed properties along pipeline route.It is suitable for protecting newly laid pipelines in areas where the flow is predominantly bidirectional，the pipeline axis is approximately perpendicular to the current direction，and the hydrodynamic conditions and seabed properties along the pipeline route are relatively uniform.
In recent years，local scour of submarine pipelines has intensified，and there is an urgent need to ensure the safe and stable operation of pipelines.In this paper，recent achievements on the protection and remediation measures for local scour of submarine pipelines were reviewed and evaluated systematically.These measures could be categorized into three groups：active methods，passive methods，and self -burial promotion.Active methods are implemented by modifying the flow field and seepage field around pipelines，including floating flow-deflecting structures，rigid guide plates，bionic grass，permeable frame structures，and rigid protective plates.Active methods offer high flexibility and often combine sediment -promotion functions.However，as their sediment -promotion effect is constrained by upstream sediment supply，they are suitable for protecting newly laid pipelines and for remedying existing scour holes around in -service pipelines.Passive methods are implemented by enhancing the seabed soil ’s resistance to scouring and seepage -induced failure，including techniques such as riprap placement，sandbagging，flexible mattress installation，and soil improvement.Passive methods，while technically mature，involve high construction and maintenance costs and have significant environmental impacts.They are applicable for remedying pipeline spanning caused by geomorphic evolution and for emergency remediation of long -distance spanning.Promoting pipeline self -burial is achieved by accelerating the self -burial process，enabling the pipeline to be embedded in the seabed within a short period.This primarily includes methods such as spoilers.Once self -buried，the pipeline ’s risk of scour is significantly reduced.However，this approach imposes specific requirements on the local hydrodynamic conditions and seabed properties along pipeline route.It is suitable for protecting newly laid pipelines in areas where the flow is predominantly bidirectional，the pipeline axis is approximately perpendicular to the current direction，and the hydrodynamic conditions and seabed properties along the pipeline route are relatively uniform.
2025,22(6):165-177
,DOI: 10.19951/j.cnki.1672-9331.20250724001
Abstract:
［Purposes ］ Brick -clad rammed earth city wall constitutes a significant component of China’s historical and cultural heritage.Investigating their defect characteristics and underlying causes holds great importance for guiding protection and restoration efforts.［Methods］ By taking Xi’an City Wall as the background，the defect characteristics of brick -clad rammed earth city walls were investigated on the spot，and the position，shape，and development degree of various defects were recorded systematically.The causes of defects of the city wall under pedestrian load，rainfall，and earthquake conditions，as well as material deterioration，were studied by the numerical simulation method.［Findings］ The primary defects observed in Xi ’an City Wall include cracking，bulging，uneven settlement，denudation，and salt precipitation.Vertical cracks at variable cross -sections，such as those at the corners of enemy platforms，account for over 80% of total cracks，with depths predominantly ranging from 0.5 to 2.0 m.Masonry within 4 m of the external wall top exhibits severe weathering.Under normal service conditions，the city wall maintains self -stability，with the maximum tensile stress of the paved floor reaching approximately 0.26 MPa.Pedestrian loads exacerbate the propagation of micro -cracks at the wall top.Rainfall induces outward deflection of both internal and external walls，with maximum displacements of 0.26 mm and 0.17 mm.During earthquakes，horizontal differential deformation occurs between the upper and lower wall segments at a height of 5 m，rendering the middle section prone to horizontal cracking.When rammed earth deteriorates by 20%，shear stress at the wall foot approaches the strength limit.At 60% deterioration of rammed earth，the maximum settlement of the inner core soil reaches 12 mm，with a horizontal displacement of approximately 1 mm at the wall top.The deterioration of masonry and foundation has little influence on the overall stability.［Conclusions ］ The performance of the brick -clad rammed earth city wall is predominantly governed by the rammed earth.Rainfall emerges as the key external factor diminishing safety.Earthquakes significantly elevate the risk of overturning.The study clarifies the characteristics and causes of defects in brick -clad rammed earth city walls，thereby providing a scientific basis for the protection and restoration of ancient city walls.
［Purposes ］ Brick -clad rammed earth city wall constitutes a significant component of China’s historical and cultural heritage.Investigating their defect characteristics and underlying causes holds great importance for guiding protection and restoration efforts.［Methods］ By taking Xi’an City Wall as the background，the defect characteristics of brick -clad rammed earth city walls were investigated on the spot，and the position，shape，and development degree of various defects were recorded systematically.The causes of defects of the city wall under pedestrian load，rainfall，and earthquake conditions，as well as material deterioration，were studied by the numerical simulation method.［Findings］ The primary defects observed in Xi ’an City Wall include cracking，bulging，uneven settlement，denudation，and salt precipitation.Vertical cracks at variable cross -sections，such as those at the corners of enemy platforms，account for over 80% of total cracks，with depths predominantly ranging from 0.5 to 2.0 m.Masonry within 4 m of the external wall top exhibits severe weathering.Under normal service conditions，the city wall maintains self -stability，with the maximum tensile stress of the paved floor reaching approximately 0.26 MPa.Pedestrian loads exacerbate the propagation of micro -cracks at the wall top.Rainfall induces outward deflection of both internal and external walls，with maximum displacements of 0.26 mm and 0.17 mm.During earthquakes，horizontal differential deformation occurs between the upper and lower wall segments at a height of 5 m，rendering the middle section prone to horizontal cracking.When rammed earth deteriorates by 20%，shear stress at the wall foot approaches the strength limit.At 60% deterioration of rammed earth，the maximum settlement of the inner core soil reaches 12 mm，with a horizontal displacement of approximately 1 mm at the wall top.The deterioration of masonry and foundation has little influence on the overall stability.［Conclusions ］ The performance of the brick -clad rammed earth city wall is predominantly governed by the rammed earth.Rainfall emerges as the key external factor diminishing safety.Earthquakes significantly elevate the risk of overturning.The study clarifies the characteristics and causes of defects in brick -clad rammed earth city walls，thereby providing a scientific basis for the protection and restoration of ancient city walls.
2025,22(6):178-195
,DOI: 10.19951/j.cnki.1672-9331.20250628001
Abstract:
［Purposes ］ The sliding block model represents a classical framework in mechanics research.Conventional analytical approaches often simplify the block as a rigid body，neglecting the influence of block deformation on interfacial shear stress distribution.By investigating the mechanical response of a deformable block interacting with a nonlinear shear interface，this study aims to elucidate how deformation properties affect the anti -sliding performance of the block.［Methods］ A coupled “deformable block -nonlinear shear interface ” model was developed.An iterative computational method was employed to systematically analyze the effects of the block ’s deformation modulus，length，slope angle，interface material composition，and boundary conditions on its anti -sliding performance.Furthermore，the mechanism by which the deformation properties of rock and soil masses trigger the progressive failure of the interface was further investigated.［Findings］ （1） The deformable block exhibits a progressive failure pattern on the nonlinear shear interface （planar），characterized by nonlinear distributions of internal forces，shear stresses，and displacements.This behavior is markedly different from the uniform shear stress distribution and synchronous failure mode observed in rigid blocks.“Deformation -shear coupling effect ” plays a critical regulatory role in the distribution of interfacial shear stress.Increasing the deformation modulus or reducing the length of the block can effectively suppress this effect，thereby efficiently enhancing the performance of interfacial shear stress.（2） The sliding behavior of a sloped block on a nonlinear shear interface is governed collectively by the gravitational sliding force，interfacial shear characteristics，and block deformability.The global triggering effect of gravitational sliding force on the interface，combined with the progressive transfer behavior under external loading，leads to high sensitivity between block stability and slope angle.（3） The intrinsic similarity between the model and natural slopes was examined：In addition to interface heterogeneity，block deformation itself can initiate progressive failure.Weakening of slopes due to external conditions may contribute to a reduction in anti -sliding performance.（4） Based on the deformability assumption of geological materials，the progressive failure process of heterogeneous interfaces was analyzed.The asynchronous mobilization mechanism of multiple locked segments was further interpreted，and the regulatory role of boundary conditions on the mechanical response of geological bodies after interface failure was discussed.［Conclusions ］ This study breaks through the limitations of traditional rigid body assumptions，revealing the regulatory mechanism of “deformation -shear coupling effect ” on the distribution of interfacial shear stress under the coupled interaction between blocks and nonlinear shear interfaces.It provides a new mechanical perspective for slope stability evaluation and the assessment of locked segment effects.
［Purposes ］ The sliding block model represents a classical framework in mechanics research.Conventional analytical approaches often simplify the block as a rigid body，neglecting the influence of block deformation on interfacial shear stress distribution.By investigating the mechanical response of a deformable block interacting with a nonlinear shear interface，this study aims to elucidate how deformation properties affect the anti -sliding performance of the block.［Methods］ A coupled “deformable block -nonlinear shear interface ” model was developed.An iterative computational method was employed to systematically analyze the effects of the block ’s deformation modulus，length，slope angle，interface material composition，and boundary conditions on its anti -sliding performance.Furthermore，the mechanism by which the deformation properties of rock and soil masses trigger the progressive failure of the interface was further investigated.［Findings］ （1） The deformable block exhibits a progressive failure pattern on the nonlinear shear interface （planar），characterized by nonlinear distributions of internal forces，shear stresses，and displacements.This behavior is markedly different from the uniform shear stress distribution and synchronous failure mode observed in rigid blocks.“Deformation -shear coupling effect ” plays a critical regulatory role in the distribution of interfacial shear stress.Increasing the deformation modulus or reducing the length of the block can effectively suppress this effect，thereby efficiently enhancing the performance of interfacial shear stress.（2） The sliding behavior of a sloped block on a nonlinear shear interface is governed collectively by the gravitational sliding force，interfacial shear characteristics，and block deformability.The global triggering effect of gravitational sliding force on the interface，combined with the progressive transfer behavior under external loading，leads to high sensitivity between block stability and slope angle.（3） The intrinsic similarity between the model and natural slopes was examined：In addition to interface heterogeneity，block deformation itself can initiate progressive failure.Weakening of slopes due to external conditions may contribute to a reduction in anti -sliding performance.（4） Based on the deformability assumption of geological materials，the progressive failure process of heterogeneous interfaces was analyzed.The asynchronous mobilization mechanism of multiple locked segments was further interpreted，and the regulatory role of boundary conditions on the mechanical response of geological bodies after interface failure was discussed.［Conclusions ］ This study breaks through the limitations of traditional rigid body assumptions，revealing the regulatory mechanism of “deformation -shear coupling effect ” on the distribution of interfacial shear stress under the coupled interaction between blocks and nonlinear shear interfaces.It provides a new mechanical perspective for slope stability evaluation and the assessment of locked segment effects.
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Estimation of adsorbed nitrogen and phosphorus load in Datong Lake Basin based on soil loss equation
2023,20(4):64-75
,DOI: 10.19951/j.cnki.1672-9331.20221124001
Abstract:
[Purposes] The water quality of Datong Lake has been in Class three or below for a long time, and the main pollutants exceeding the standard are total nitrogen and total phosphorus. By estimating pollution loads of absorbed nitrogen and phosphorus in Datong Lake basin, it provides a scientific basis for water environment management and protection in Datong Lake area. [Methods] The study used the modified general soil erosion equation, coupled with the adsorbed nitrogen and phosphorus pollution loads model to estimate the adsorbed nitrogen and phosphorus pollution loads in the study area, focusing on analyzing the spatial distribution characteristics of adsorbed nitrogen and phosphorus pollution in the Datong Lake Basin. [Findings] The model calculation results showed that in 2020, the total soil erosion in Datong Lake Basin was 4804.8 t, the average soil erosion modulus was 5.20 t/(km2·a), the adsorption nitrogen and phosphorus loads were 4.943 t and 2.098 t, respectively. According to the adsorbed nitrogen and phosphorus pollution load modulus of each land use type in the basin, the order from large to small is: forest land, cultivated land, construction land. According to the administrative area, Maocaojie, Qingshuzui, Wuzui, Mingshandou and Heba Town adsorbed nitrogen and phosphorus pollution were more serious; The load of nitrogen and phosphorus pollution in the Wuqi Canal basin, the Suhe River basin, the Daxin River basin, the Datong Lake West into the lake area, and the Caoyang Canal area are larger. [Conclusions] The soil erosion intensity in the Datong Lake basin is mainly slight erosion, and cultivated land is the main source of adsorbed nitrogen and phosphorus loss. For areas with large loss of adsorbed nitrogen and phosphorus, it can be controlled according to the ideas of source reduction, process interception, and end-treatment. At the same time, the agricultural planting structure should be adjusted appropriately, the farming methods should be improved, and the soil and water conservation measures should be improved to reduce the soil loss and reduce the direct impact of adsorbed nitrogen and phosphorus pollutants on the water bodies.
[Purposes] The water quality of Datong Lake has been in Class three or below for a long time, and the main pollutants exceeding the standard are total nitrogen and total phosphorus. By estimating pollution loads of absorbed nitrogen and phosphorus in Datong Lake basin, it provides a scientific basis for water environment management and protection in Datong Lake area. [Methods] The study used the modified general soil erosion equation, coupled with the adsorbed nitrogen and phosphorus pollution loads model to estimate the adsorbed nitrogen and phosphorus pollution loads in the study area, focusing on analyzing the spatial distribution characteristics of adsorbed nitrogen and phosphorus pollution in the Datong Lake Basin. [Findings] The model calculation results showed that in 2020, the total soil erosion in Datong Lake Basin was 4804.8 t, the average soil erosion modulus was 5.20 t/(km2·a), the adsorption nitrogen and phosphorus loads were 4.943 t and 2.098 t, respectively. According to the adsorbed nitrogen and phosphorus pollution load modulus of each land use type in the basin, the order from large to small is: forest land, cultivated land, construction land. According to the administrative area, Maocaojie, Qingshuzui, Wuzui, Mingshandou and Heba Town adsorbed nitrogen and phosphorus pollution were more serious; The load of nitrogen and phosphorus pollution in the Wuqi Canal basin, the Suhe River basin, the Daxin River basin, the Datong Lake West into the lake area, and the Caoyang Canal area are larger. [Conclusions] The soil erosion intensity in the Datong Lake basin is mainly slight erosion, and cultivated land is the main source of adsorbed nitrogen and phosphorus loss. For areas with large loss of adsorbed nitrogen and phosphorus, it can be controlled according to the ideas of source reduction, process interception, and end-treatment. At the same time, the agricultural planting structure should be adjusted appropriately, the farming methods should be improved, and the soil and water conservation measures should be improved to reduce the soil loss and reduce the direct impact of adsorbed nitrogen and phosphorus pollutants on the water bodies.
2023,20(6):109-118
,DOI: 10.19951/j.cnki.1672-9331.20230524001
Abstract:
[Purposes] In order to meet the customized requirements of low energy-consumption and light-weight elevator car, a variation design framework of modular car structure based on "Internet + " is constructed. [Methods] First of all, under the B/S architecture, Vue technology was used to develop user-defined design data acquisition front-end to obtain customized design requirements, and Springboot technology was used to develop modular structure variation design back-end. A Web framework for front-end separation was built, which can realize bidirectional binding of front-end and back-end data. Secondly, a topology optimization design method for high-specific stiffness considering stress constraints was embedded in the back end. The strength and volume fraction of the car structure was considered as user-defined constraints，and the maximum stiffness of the car modular structure was optimized as the optimization goal. The moving asymptotic optimization algorithm was used as the solver to drive the rapid customized variation design of the lightweight car modular structure. Then, the heavyside function was introduced into the optimization method to ensure that the design results have clear geometric boundaries. Finally, taking a certain type of backpack elevator car frame as an example, the geometric and mechanical boundary parameters of the car structure were set in the user-defined interface to carry out the variation design of the innovative lightweight car frame structure, and the finite element simulation analysis was carried out. [Findings] Under the premise of given design requirements, the structural variation process was stable and convergent, and the geometric boundary of the designed structure was clear. Under the same mechanical boundary conditions and meeting the 2 times minimum safety factor of the material, the mass of the designed car frame structure reduced 16.09% comparing with the original structure.The structural deformation was ensured to meet the practical application requirements, and the specific stiffness was significantly improved, which verified the effectiveness of the structural variation design framework established in this paper. [Conclusions] The proposed design framework can improve the specific stiffness of the structure under the premise of ensuring the strength of the structure, which can be effectively applied to the rapid customized design of the lightweight elevator car modular structure. It can shorten the design cycle of the car modular structure, and enrich the design means of the car modular structure.
[Purposes] In order to meet the customized requirements of low energy-consumption and light-weight elevator car, a variation design framework of modular car structure based on "Internet + " is constructed. [Methods] First of all, under the B/S architecture, Vue technology was used to develop user-defined design data acquisition front-end to obtain customized design requirements, and Springboot technology was used to develop modular structure variation design back-end. A Web framework for front-end separation was built, which can realize bidirectional binding of front-end and back-end data. Secondly, a topology optimization design method for high-specific stiffness considering stress constraints was embedded in the back end. The strength and volume fraction of the car structure was considered as user-defined constraints，and the maximum stiffness of the car modular structure was optimized as the optimization goal. The moving asymptotic optimization algorithm was used as the solver to drive the rapid customized variation design of the lightweight car modular structure. Then, the heavyside function was introduced into the optimization method to ensure that the design results have clear geometric boundaries. Finally, taking a certain type of backpack elevator car frame as an example, the geometric and mechanical boundary parameters of the car structure were set in the user-defined interface to carry out the variation design of the innovative lightweight car frame structure, and the finite element simulation analysis was carried out. [Findings] Under the premise of given design requirements, the structural variation process was stable and convergent, and the geometric boundary of the designed structure was clear. Under the same mechanical boundary conditions and meeting the 2 times minimum safety factor of the material, the mass of the designed car frame structure reduced 16.09% comparing with the original structure.The structural deformation was ensured to meet the practical application requirements, and the specific stiffness was significantly improved, which verified the effectiveness of the structural variation design framework established in this paper. [Conclusions] The proposed design framework can improve the specific stiffness of the structure under the premise of ensuring the strength of the structure, which can be effectively applied to the rapid customized design of the lightweight elevator car modular structure. It can shorten the design cycle of the car modular structure, and enrich the design means of the car modular structure.
2023,20(5):1-24
,DOI: 10.19951/j.cnki.1672-9331.20231008002
Abstract:
Geopolymer is a new type of inorganic cementitious material developed in recent years. It not only realizes the resource reuse of industrial solid wastes, but also contributes to the reduced energy consumption and greenhouse gas emissions, and is considered a green cementitious material with the potential to replace ordinary Portland cement (OPC). To address the durability of geopolymer concrete, this paper compared and summarized the durability performance of geopolymer concrete and cement-based concrete from four aspects, namely, the resistance to chemical attack (salt and acid resistance), carbonation, chloride penetration, and frost resistance. It was found that geopolymer concrete exhibited superior chemical resistance, chloride penetration resistance, and frost resistance, but slightly lower carbonation resistance than cement-based concrete. However, due to the diversity of raw materials, the microstructure, mechanical properties, and deterioration mechanisms were different for each type of geopolymer concrete, thereby resulting in large differences in their durability. Under these environmental attacks, the deterioration mechanisms of geopolymer concrete were mainly attributed to the dissolved hydration products, the formed expansion products, the generated cracks, and the increased porosity.
Geopolymer is a new type of inorganic cementitious material developed in recent years. It not only realizes the resource reuse of industrial solid wastes, but also contributes to the reduced energy consumption and greenhouse gas emissions, and is considered a green cementitious material with the potential to replace ordinary Portland cement (OPC). To address the durability of geopolymer concrete, this paper compared and summarized the durability performance of geopolymer concrete and cement-based concrete from four aspects, namely, the resistance to chemical attack (salt and acid resistance), carbonation, chloride penetration, and frost resistance. It was found that geopolymer concrete exhibited superior chemical resistance, chloride penetration resistance, and frost resistance, but slightly lower carbonation resistance than cement-based concrete. However, due to the diversity of raw materials, the microstructure, mechanical properties, and deterioration mechanisms were different for each type of geopolymer concrete, thereby resulting in large differences in their durability. Under these environmental attacks, the deterioration mechanisms of geopolymer concrete were mainly attributed to the dissolved hydration products, the formed expansion products, the generated cracks, and the increased porosity.
2022,19(3):104-121
,DOI: 10.19951/j.cnki.1672-9331.2022.03.011
Abstract:
Traveling wave location technology can quickly and accurately locate the fault according to the collected time information when the high-voltage AC transmission line fault occurs in the system. Due to its high location accuracy, it has attracted extensive attention. This paper introduces the development of traveling wave location technology at home and abroad from the aspects of accurate detection of traveling wave signal, high-precision synchronous clock technology, fault location algorithm and engineering practice. Then it introduces the working principles and their advantages and disadvantages of single-end traveling wave location, double-end traveling wave location and network traveling wave location methods. The main technical problems existing in the traditional traveling wave location research have been analysed, which puts forward the corresponding solutions. Finally, the development prospect of traveling wave location technology is prospected, in order to provide reference for subsequent research.
Traveling wave location technology can quickly and accurately locate the fault according to the collected time information when the high-voltage AC transmission line fault occurs in the system. Due to its high location accuracy, it has attracted extensive attention. This paper introduces the development of traveling wave location technology at home and abroad from the aspects of accurate detection of traveling wave signal, high-precision synchronous clock technology, fault location algorithm and engineering practice. Then it introduces the working principles and their advantages and disadvantages of single-end traveling wave location, double-end traveling wave location and network traveling wave location methods. The main technical problems existing in the traditional traveling wave location research have been analysed, which puts forward the corresponding solutions. Finally, the development prospect of traveling wave location technology is prospected, in order to provide reference for subsequent research.
2022,19(1):73-80
,DOI: 10.19951/j.cnki.1672-9331.2022.01.009
Abstract:
[Purposes]The paper explores the use of "bigdata"to innovate the prediction method of urban residents'travel volume(OD), improve the time-consuming,laborious and inaccurate problems of traditional urban residents'travel survey methods, and also provide reliable data support for urban public transportation planning and management. [Methods] Combining the characteristics and advantages of mobile phone signaling data,bus IC card, bus GPS and subway gate data, the OD matrix of urban residents'public transportation travel was obtained by cluster analysis and other methods,and the wavelet neural network combined with optimized whale algorithm (IWOA-WNN)was used to predict the travel OD matrix of future time period. Taking Changsha City as an example, the original data during the 60 d evening peak period were selected, the IWOA-WNN was used for prediction, and the time series method was combined for analysis. [Findings]Compared with the wavelet neural network before optimization, the prediction results of IWOA-WNN are closer to the actual situation, and the accuracy reaches 93.36%. [Conclusions]The methods of data processing and prediction proposed in this study have higher accuracy.
[Purposes]The paper explores the use of "bigdata"to innovate the prediction method of urban residents'travel volume(OD), improve the time-consuming,laborious and inaccurate problems of traditional urban residents'travel survey methods, and also provide reliable data support for urban public transportation planning and management. [Methods] Combining the characteristics and advantages of mobile phone signaling data,bus IC card, bus GPS and subway gate data, the OD matrix of urban residents'public transportation travel was obtained by cluster analysis and other methods,and the wavelet neural network combined with optimized whale algorithm (IWOA-WNN)was used to predict the travel OD matrix of future time period. Taking Changsha City as an example, the original data during the 60 d evening peak period were selected, the IWOA-WNN was used for prediction, and the time series method was combined for analysis. [Findings]Compared with the wavelet neural network before optimization, the prediction results of IWOA-WNN are closer to the actual situation, and the accuracy reaches 93.36%. [Conclusions]The methods of data processing and prediction proposed in this study have higher accuracy.
2023,20(6):91-99
,DOI: 10.19951/j.cnki.1672-9331.20220417001
Abstract:
[Purposes] This work aims to demonstrate the semi-open graded asphalt mixture BK-7 with a nominal maximum particle size of 7 mm. [Methods] In this paper, the mineral composition formulation of BK-7 mixture was designed. The amount of SBS modified asphalt was determined by Schellenberg leakage test and Kantabaugh flying test when the fiber content was 0.4%. Uniaxial penetration test, low temperature bending test and Marshall stability test of BK-7 mixture with 9%, 11% and 13% porosity were carried out, and the corresponding properties of BK-7 mixture were compared with those of SMA-5, AC-5 and OGFC-5. At the same time, flying and Marshall tests were carried out on BK-7 mixture with 11% porosity soaked in acid solution. [Findings] Among the three kinds of BK-7 mixture, the BK-7 mixture with 9% porosity has the best road performance and the best rutting resistance, and its low temperature crack resistance and water stability are comparable to those of SMA-5 and AC-5 asphalt mixture. After soaking in acid rain solution with pH=4 for 2 cycles (" Soaking for 7 days, natural drying for 1 day "for 1 cycle), the Marshall stability of BK-7 mixture with 11% porosity and the flight loss of Fort Kenta could meet the corresponding specification requirements. [Conclusions] The road performance of BK-7 asphalt mixture with 9% porosity of SBS modified asphalt mixed with fiber has comparative advantages, and it has certain engineering application value in South China where exhibits a high-temperature climate throughout a year.
[Purposes] This work aims to demonstrate the semi-open graded asphalt mixture BK-7 with a nominal maximum particle size of 7 mm. [Methods] In this paper, the mineral composition formulation of BK-7 mixture was designed. The amount of SBS modified asphalt was determined by Schellenberg leakage test and Kantabaugh flying test when the fiber content was 0.4%. Uniaxial penetration test, low temperature bending test and Marshall stability test of BK-7 mixture with 9%, 11% and 13% porosity were carried out, and the corresponding properties of BK-7 mixture were compared with those of SMA-5, AC-5 and OGFC-5. At the same time, flying and Marshall tests were carried out on BK-7 mixture with 11% porosity soaked in acid solution. [Findings] Among the three kinds of BK-7 mixture, the BK-7 mixture with 9% porosity has the best road performance and the best rutting resistance, and its low temperature crack resistance and water stability are comparable to those of SMA-5 and AC-5 asphalt mixture. After soaking in acid rain solution with pH=4 for 2 cycles (" Soaking for 7 days, natural drying for 1 day "for 1 cycle), the Marshall stability of BK-7 mixture with 11% porosity and the flight loss of Fort Kenta could meet the corresponding specification requirements. [Conclusions] The road performance of BK-7 asphalt mixture with 9% porosity of SBS modified asphalt mixed with fiber has comparative advantages, and it has certain engineering application value in South China where exhibits a high-temperature climate throughout a year.
2023,20(3):14-31
,DOI: 10.19951/j.cnki.1672-9331.20220913001
Abstract:
Recent years, with the massive consumption of lithium and the strong increase in the price of lithium, the application of lithium battery is limited in some extent.?With the similar working principle and battery components, sodium-ion batteries have exhibited a great opportunity for development and attracted extensive attention of many researchers.?Polyanionic compounds have the advantages of high and stable voltage platform, diverse structure, stable structure and fast diffusion rate of sodium-ions, which have become the research hotspot of cathode materials for sodium batteries. However, their large anionic groups lead to poor electron rate, which limits the specific capacity and rate capability of the materials.?In this review, the research status of various polyanionic cathode materials is mentioned, which have discussed the relationship between crystal structure and electrochemical properties of the materials, some modification strategies including element doping and substitution, carbon coating and carbon recombination, and nanostructure design.
Recent years, with the massive consumption of lithium and the strong increase in the price of lithium, the application of lithium battery is limited in some extent.?With the similar working principle and battery components, sodium-ion batteries have exhibited a great opportunity for development and attracted extensive attention of many researchers.?Polyanionic compounds have the advantages of high and stable voltage platform, diverse structure, stable structure and fast diffusion rate of sodium-ions, which have become the research hotspot of cathode materials for sodium batteries. However, their large anionic groups lead to poor electron rate, which limits the specific capacity and rate capability of the materials.?In this review, the research status of various polyanionic cathode materials is mentioned, which have discussed the relationship between crystal structure and electrochemical properties of the materials, some modification strategies including element doping and substitution, carbon coating and carbon recombination, and nanostructure design.
2023,20(5):25-40
,DOI: 10.19951/j.cnki.1672-9331.20230410001
Abstract:
[Purposes] The design of cementitious materials utilizing solid waste to replace cement, which reduces energy and resource consumption and environmental pollution, as well as realizes the resource utilization of solid waste. Based on the reaction mechanism of alkali-activated binder and the action mechanism of their raw material components, this paper proposes a design method of all-solid-waste-based alkali-activated binders. [Methods]The CGF+P series cementitious materials comprising calcium carbide slag (CCR), ground granulated blast furnace slag (GGBS), fly ash (FA), and phosphogypsum (PG) are designed, and the design method is verified by using macro and micro tests of paste. [Findings] The alkali activator and pozzolanic materials with highly activity have a significant effect on the setting time of paste, the higher its content, the shorter the initial and final setting time; The strength of paste is governed by the relative content of alkali activator and pozzolanic materials, the higher the content of pozzolanic materials with highly activity the higher the early strength, and vice versa. [Conclusions] The design method of all-solid-waste-based alkali-activated binders includes component classification method, component screening method, and component distribution ratio design method, which has a practical value.
[Purposes] The design of cementitious materials utilizing solid waste to replace cement, which reduces energy and resource consumption and environmental pollution, as well as realizes the resource utilization of solid waste. Based on the reaction mechanism of alkali-activated binder and the action mechanism of their raw material components, this paper proposes a design method of all-solid-waste-based alkali-activated binders. [Methods]The CGF+P series cementitious materials comprising calcium carbide slag (CCR), ground granulated blast furnace slag (GGBS), fly ash (FA), and phosphogypsum (PG) are designed, and the design method is verified by using macro and micro tests of paste. [Findings] The alkali activator and pozzolanic materials with highly activity have a significant effect on the setting time of paste, the higher its content, the shorter the initial and final setting time; The strength of paste is governed by the relative content of alkali activator and pozzolanic materials, the higher the content of pozzolanic materials with highly activity the higher the early strength, and vice versa. [Conclusions] The design method of all-solid-waste-based alkali-activated binders includes component classification method, component screening method, and component distribution ratio design method, which has a practical value.
2022,19(1):96-104
,DOI: 10.19951/j.cnki.1672-9331.2022.01.012
Abstract:
[Purposes]The paper explored the problem of green multimodal transportation route optimization under mixed uncertainties of the transport time, transit time,waiting time and freight damage rate to provide theoretical basis for green multimodal transport route decision. [Methods]Based on the consideration of carbon emission and noise pollution in the transport process,aiming to minimize transportation cost, transportation time,carbon emission, noise pollution and cargo damage, a green multimodal transportation route optimization model under uncertainties was established, and the uncertain parameters were processed by extending the model to fuzzy chance-constrained model and robust optimization model. Programming with MATLAB and calling CPLEX to solve the example,the multi-modal transportation route optimization scheme was obtained. The sensitivity of the confi- dence level was analyzed and the robust solution was compared with the optimal solution under certainties to verify the robustness of the model. [Findings]The comparison between calculation results of the optimization scheme and the optimal values of the five objective functions shows that the relative distances between the calculation results of the optimal transport scheme and the optimal values of the objective functions are 0.0964, 0.0271, 0.1946, 0.0184 and 0.0327 respectively, namely, the calculation results are close to the optimal values. [Conclusions]The model proposed in the paper can reduce the decision- making risk and provide reasonable and effective basis for decision-making.
[Purposes]The paper explored the problem of green multimodal transportation route optimization under mixed uncertainties of the transport time, transit time,waiting time and freight damage rate to provide theoretical basis for green multimodal transport route decision. [Methods]Based on the consideration of carbon emission and noise pollution in the transport process,aiming to minimize transportation cost, transportation time,carbon emission, noise pollution and cargo damage, a green multimodal transportation route optimization model under uncertainties was established, and the uncertain parameters were processed by extending the model to fuzzy chance-constrained model and robust optimization model. Programming with MATLAB and calling CPLEX to solve the example,the multi-modal transportation route optimization scheme was obtained. The sensitivity of the confi- dence level was analyzed and the robust solution was compared with the optimal solution under certainties to verify the robustness of the model. [Findings]The comparison between calculation results of the optimization scheme and the optimal values of the five objective functions shows that the relative distances between the calculation results of the optimal transport scheme and the optimal values of the objective functions are 0.0964, 0.0271, 0.1946, 0.0184 and 0.0327 respectively, namely, the calculation results are close to the optimal values. [Conclusions]The model proposed in the paper can reduce the decision- making risk and provide reasonable and effective basis for decision-making.
2017(3):29-34
Abstract:
In order to study thediffer ence of several most commonly used active earth-pres sure theories， with horizontal cohesive soil for example， compared and analyzed the distri-bution and value tendency of earth pressure of these three theories， and analyzed the stress distribution of retaining walls by finite element method.A method is used in solving process for horizontal layer element method， which used interpolation derivation formula to solve the most unfavorable fracture angle θ The results show that the distribution of horizontal layer element method is close to measured value.Meanwhile， some important parameters effect the stability of retaining walls tally with the measured value， which indicate that hori-zontal layer element method is more practical.
In order to study thediffer ence of several most commonly used active earth-pres sure theories， with horizontal cohesive soil for example， compared and analyzed the distri-bution and value tendency of earth pressure of these three theories， and analyzed the stress distribution of retaining walls by finite element method.A method is used in solving process for horizontal layer element method， which used interpolation derivation formula to solve the most unfavorable fracture angle θ The results show that the distribution of horizontal layer element method is close to measured value.Meanwhile， some important parameters effect the stability of retaining walls tally with the measured value， which indicate that hori-zontal layer element method is more practical.
2021,18(1):95-101
,DOI: 10.19951/j.cnki.cslgdxxbzkb.2021.01.012
Abstract:
Aiming at the influence of uncertain ties on the vehicle structural crash worthiness, are liability-based design optimization (RBDO)method for vehicle structural crash worthiness based on hybrid model was proposed.First,a RBDO model for vehicle structural crash worthiness based on probability and interval hybrid model was established,and the nesting level was analyzed.Then,in order to reduce the nesting,an efficient decoupling strategy was proposed,which transformed the original nesting problem into a single-layer design optimization problem.Finally,the approximate RBDO problem was constructed by using the radial basis function.The local densifying strategy was employed to improve the accuracy of the results.The research results show that the method converges rapidly,and the RBDO problem of vehicle structural crash worthinessis solved quickly.It has a wide application prospect in the field of vehicle crash worthiness design optimization,which has cer- tain reference value for the design optimization of vehicle structural crash worthiness.
Aiming at the influence of uncertain ties on the vehicle structural crash worthiness, are liability-based design optimization (RBDO)method for vehicle structural crash worthiness based on hybrid model was proposed.First,a RBDO model for vehicle structural crash worthiness based on probability and interval hybrid model was established,and the nesting level was analyzed.Then,in order to reduce the nesting,an efficient decoupling strategy was proposed,which transformed the original nesting problem into a single-layer design optimization problem.Finally,the approximate RBDO problem was constructed by using the radial basis function.The local densifying strategy was employed to improve the accuracy of the results.The research results show that the method converges rapidly,and the RBDO problem of vehicle structural crash worthinessis solved quickly.It has a wide application prospect in the field of vehicle crash worthiness design optimization,which has cer- tain reference value for the design optimization of vehicle structural crash worthiness.
2022,19(3):69-77
,DOI: 10.19951/j.cnki.1672-9331.2022.03.007
Abstract:
［Purposes］ The paper aims to study the deformation evolution law of the excavation of huge deep foundation pits in complex environments and optimize the design of support structures.［Methods］ Based on the foundation pit engineering of Guangzhou Metro Line 11, the variation laws of the horizontal displacement of support structures and the surface settlement of the surrounding soil were studied by using the finite-difference software FLAC3D in the foundation pit excavation project. By analyzing the influence of the embedded depth, the thickness of the diaphragm wall, and the number of layers of support structure on the deformation of the foundation pit, the support structure of the foundation pit was optimized. The support effect before and after the optimization of the support structure was compared and analyzed.［Findings］ Under different operating conditions, the surface settlement of the surrounding soil first increases and then decreases, and the largest settlement occurs at the position of 15.0 m from the edge of the foundation pit; Under different embedded depths, the variation trends of the horizontal displacement of diaphragm wall and the surface settlement of surrounding soil are basically the same; The change of the thickness of diaphragm wall has no obvious effect on its horizontal displacement and surface settlement; The increase of the number of support layers can significantly reduce the horizontal displacement of the support structure and the maximal settlement of the surrounding soil. After the optimization of support structures, the maximal settlement of the surrounding soil is reduced by 23.88%, and the maximal horizontal displacement of diaphragm wall is reduced by 1919%.［Conclusions］ In the design of the same type of foundation pit, attention should be paid to the selection of the number of support layers. The thickness of support structure can be appropriately reduced if necessary.
［Purposes］ The paper aims to study the deformation evolution law of the excavation of huge deep foundation pits in complex environments and optimize the design of support structures.［Methods］ Based on the foundation pit engineering of Guangzhou Metro Line 11, the variation laws of the horizontal displacement of support structures and the surface settlement of the surrounding soil were studied by using the finite-difference software FLAC3D in the foundation pit excavation project. By analyzing the influence of the embedded depth, the thickness of the diaphragm wall, and the number of layers of support structure on the deformation of the foundation pit, the support structure of the foundation pit was optimized. The support effect before and after the optimization of the support structure was compared and analyzed.［Findings］ Under different operating conditions, the surface settlement of the surrounding soil first increases and then decreases, and the largest settlement occurs at the position of 15.0 m from the edge of the foundation pit; Under different embedded depths, the variation trends of the horizontal displacement of diaphragm wall and the surface settlement of surrounding soil are basically the same; The change of the thickness of diaphragm wall has no obvious effect on its horizontal displacement and surface settlement; The increase of the number of support layers can significantly reduce the horizontal displacement of the support structure and the maximal settlement of the surrounding soil. After the optimization of support structures, the maximal settlement of the surrounding soil is reduced by 23.88%, and the maximal horizontal displacement of diaphragm wall is reduced by 1919%.［Conclusions］ In the design of the same type of foundation pit, attention should be paid to the selection of the number of support layers. The thickness of support structure can be appropriately reduced if necessary.
2022,19(1):1-11
,DOI: 10.19951/j.cnki.1672-9331.2022.01.001
Abstract:
[Purposes]The paper aims to explore the effectiveness of the multi-scale algo- rithm in studying the mechanical characteristics of splitting fatigue damage of asphalt mix-ture．[Methods]By dividing five scale areas, the multi-scale analysis of five different gradations of asphalt mixtures was conducted, the splitting strengths were calculated under different fatigue damage degrees,the splitting strengths obtained by the indoor test and the multi-scale algorithm were compared and analyzed to verify the rationality of the multi-scale algorithm in studying the mechanical characteristics of splitting fatigue damage of asphalt mixture. [Findings]The splitting strength of asphalt mixture with aggregate particle size of 1.18-2.36 mm has been greatly improved, the absolute values of relative errors between the splitting strengths obtained by the multi-scale algorithm and that obtained by the indoor test are all within 10%, which meets the engineering accuracy requirements. [Conclusions]The multi-scale algorithm is feasible to study the mechanical characteristics of splitting fatigue damage of asphalt mixture, and has certain application value in practical engineering.
[Purposes]The paper aims to explore the effectiveness of the multi-scale algo- rithm in studying the mechanical characteristics of splitting fatigue damage of asphalt mix-ture．[Methods]By dividing five scale areas, the multi-scale analysis of five different gradations of asphalt mixtures was conducted, the splitting strengths were calculated under different fatigue damage degrees,the splitting strengths obtained by the indoor test and the multi-scale algorithm were compared and analyzed to verify the rationality of the multi-scale algorithm in studying the mechanical characteristics of splitting fatigue damage of asphalt mixture. [Findings]The splitting strength of asphalt mixture with aggregate particle size of 1.18-2.36 mm has been greatly improved, the absolute values of relative errors between the splitting strengths obtained by the multi-scale algorithm and that obtained by the indoor test are all within 10%, which meets the engineering accuracy requirements. [Conclusions]The multi-scale algorithm is feasible to study the mechanical characteristics of splitting fatigue damage of asphalt mixture, and has certain application value in practical engineering.
2021,18(1):7-15
,DOI: 10.19951/j.cnki.cslgdxxbzkb.2021.01.002
Abstract:
The existing safety risk identification methods of subway tunnel construction lack certain systematicness,and lack multiimensional risk scenario identification in the risk identification process, so they have certain limitation. Based on the hierarchical holographic modeling (HHM) method,risk filtering,ranking and management(RFRM)framework and scenario analysis theory,a HHM method for identifying risk scenarios in subway tunnel construction was constructed. The risk scenarios were identified from multiple perspectives, and were filtered and sorted by the RFRM framework four-times to screen the keyrisk scenarios. The case study of a subway tunnel project in C City shows that the method can systematically and perfectly identify the safety risk scenarios and keyrisk factors of subway tunnel construction, and further layscertain foundation for risk management.
The existing safety risk identification methods of subway tunnel construction lack certain systematicness,and lack multiimensional risk scenario identification in the risk identification process, so they have certain limitation. Based on the hierarchical holographic modeling (HHM) method,risk filtering,ranking and management(RFRM)framework and scenario analysis theory,a HHM method for identifying risk scenarios in subway tunnel construction was constructed. The risk scenarios were identified from multiple perspectives, and were filtered and sorted by the RFRM framework four-times to screen the keyrisk scenarios. The case study of a subway tunnel project in C City shows that the method can systematically and perfectly identify the safety risk scenarios and keyrisk factors of subway tunnel construction, and further layscertain foundation for risk management.
2023,20(2):10-26
,DOI: 10.19951/j.cnki.1672-9331.20221214001
Abstract:
[Purposes] This study aims at directing the condition-based maintenance of equipment by expounding the connotation of complex equipment fault prognostic. [Methods] In this study, the relevant research contents, status, and methods were investigated, summarized, and analyzed. The existing fault prognostic methods were divided into different categories and the corresponding application conditions, advantages, and drawbacks were discussed. [Findings] The knowledge-based methods can take full advantage of the experiential knowledge from experts, but the knowledge acquisition was a bottleneck problem. The model-based methods had the advantages of in-depth understanding of the nature of the target systems, but it was difficult to establish accurate models for complex equipments. The data-driven methods relied on a large amount of data. However, the cost of acquiring typical data of some complex equipments was very high. The hybrid methods can overcome the limitation of a single method, but designing an effective hybrid model was challenging. [Conclusions] The hybrid methods can improve the intelligence and performance of the fault prognostic system, which is an important development trend of complex equipment falt prognostic.
[Purposes] This study aims at directing the condition-based maintenance of equipment by expounding the connotation of complex equipment fault prognostic. [Methods] In this study, the relevant research contents, status, and methods were investigated, summarized, and analyzed. The existing fault prognostic methods were divided into different categories and the corresponding application conditions, advantages, and drawbacks were discussed. [Findings] The knowledge-based methods can take full advantage of the experiential knowledge from experts, but the knowledge acquisition was a bottleneck problem. The model-based methods had the advantages of in-depth understanding of the nature of the target systems, but it was difficult to establish accurate models for complex equipments. The data-driven methods relied on a large amount of data. However, the cost of acquiring typical data of some complex equipments was very high. The hybrid methods can overcome the limitation of a single method, but designing an effective hybrid model was challenging. [Conclusions] The hybrid methods can improve the intelligence and performance of the fault prognostic system, which is an important development trend of complex equipment falt prognostic.
2022,19(4):55-63
,DOI: 10.19951/j.cnki.1672?9331.2022.04.006
Abstract:
[Purposes] The paper aims to figure out the development regulation and anisotropy of mechanical properties of 3D printed slag?fly ash?based geopolymer concrete with age. [Methods] The cubic compressive strength, axial compressive strength and flexural strength of printed geopolymer concrete at different curing ages and along x, y and z loading directions were tested in this study. X?ray CT scanner was used to analyze the microstructure and clarify the influence mechanism on the mechanical properties of printed concrete. [Findings] The mechanical strengths of printed concretes at 3 and 7 d were more 30% and 60% than that at 28 d, respectively. The printed concrete had an early strength and met the requirement of concrete printing construction. The differences in cubic compressive strength, axial compressive strength and flexural strength of the specimens cured for 28 d in each loading direction were in the range of 3.20%-10.40%, 1.53%-7.05% and 5.10%-24.00%, respectively. [Conclusions] The printed concrete exhibited certain anisotropy in mechanical performance, mainly due to the number and spatial distribution of defects in the material during the stacking process of the printed concrete.
[Purposes] The paper aims to figure out the development regulation and anisotropy of mechanical properties of 3D printed slag?fly ash?based geopolymer concrete with age. [Methods] The cubic compressive strength, axial compressive strength and flexural strength of printed geopolymer concrete at different curing ages and along x, y and z loading directions were tested in this study. X?ray CT scanner was used to analyze the microstructure and clarify the influence mechanism on the mechanical properties of printed concrete. [Findings] The mechanical strengths of printed concretes at 3 and 7 d were more 30% and 60% than that at 28 d, respectively. The printed concrete had an early strength and met the requirement of concrete printing construction. The differences in cubic compressive strength, axial compressive strength and flexural strength of the specimens cured for 28 d in each loading direction were in the range of 3.20%-10.40%, 1.53%-7.05% and 5.10%-24.00%, respectively. [Conclusions] The printed concrete exhibited certain anisotropy in mechanical performance, mainly due to the number and spatial distribution of defects in the material during the stacking process of the printed concrete.
2024,21(1):59-87
,DOI: 10.19951/j.cnki.1672-9331.20231225001
Abstract:
The subgrade is the main load-bearing structure of highways. With the transition of China′s highway construction from high-speed development to high-quality development, digital construction technology, intelligent construction, and information management have become the core technical means in subgrade engineering. This paper summarizes the research status of key technologies of construction and maintenance for intelligent highway subgrades, mainly analyzing building information modeling (BIM) technology, intelligent compaction technology for subgrades, subgrade health monitoring and assessment technology, and intelligent grouting reinforcement technology for subgrades. The current problems are as follows: the application of BIM technology in the field of subgrade engineering is still in its infancy, lacking reasonable construction quality quantification indicators and cost estimation methods. The theoretical research on intelligent compaction technology is weak, and there is limited research on quality uniformity evaluation. Existing measurement methods for subgrade monitoring and assessment technology are susceptible to interference from other factors and require significant human intervention. In addition, there is no unified quality evaluation index for grouting reinforcement technology, mostly relying on engineering experience and theoretical analysis for evaluation. Therefore, it is necessary to conduct intelligent theoretical and applied research on various key technologies to address the proposed problems and provide guidance for the intelligent construction and maintenance of subgrade engineering in the future.
The subgrade is the main load-bearing structure of highways. With the transition of China′s highway construction from high-speed development to high-quality development, digital construction technology, intelligent construction, and information management have become the core technical means in subgrade engineering. This paper summarizes the research status of key technologies of construction and maintenance for intelligent highway subgrades, mainly analyzing building information modeling (BIM) technology, intelligent compaction technology for subgrades, subgrade health monitoring and assessment technology, and intelligent grouting reinforcement technology for subgrades. The current problems are as follows: the application of BIM technology in the field of subgrade engineering is still in its infancy, lacking reasonable construction quality quantification indicators and cost estimation methods. The theoretical research on intelligent compaction technology is weak, and there is limited research on quality uniformity evaluation. Existing measurement methods for subgrade monitoring and assessment technology are susceptible to interference from other factors and require significant human intervention. In addition, there is no unified quality evaluation index for grouting reinforcement technology, mostly relying on engineering experience and theoretical analysis for evaluation. Therefore, it is necessary to conduct intelligent theoretical and applied research on various key technologies to address the proposed problems and provide guidance for the intelligent construction and maintenance of subgrade engineering in the future.
2019(1):66-72
Abstract:
In order to study the pressure characteristics of the underwater shock wave in the infinite water and near air-water surface and the physical characteristics of the air-water surface,three-dimensional numerical simulationof infinite water and near air-water surface underwater explosion was carried out based on the arbitrary Lagrangian-Eulerianmethod by finite eldment software ANSYS/LS-DYNA.The interaction between the water and the air during the process of explosion is investigated .According to analysis,we found that in the condition of the depth of detonation remaining unchanged, the influence of air-water surface on shock wave is mainly reflected in reducing the pulse width of incident shock wave and reducing the peak pressure of shock wave with the decrease of sounding depth. The height of water column produced by the same TNT explosive on the air-water surface increases with the decrease of the detonation depth. At the same time, the density distribution near air-water surfaceand the process of water column forming under different detonation depths are qualitatively analyzed, which is also reproduced with three-dimensional numerical simulation method.With the numerical simulation method, the characteristics of the shock wave values are analyzed and certify that the model has better calculation accuracy compared with the empirical formula,and the process of underwater explosion near air-water surface is also represented.
In order to study the pressure characteristics of the underwater shock wave in the infinite water and near air-water surface and the physical characteristics of the air-water surface,three-dimensional numerical simulationof infinite water and near air-water surface underwater explosion was carried out based on the arbitrary Lagrangian-Eulerianmethod by finite eldment software ANSYS/LS-DYNA.The interaction between the water and the air during the process of explosion is investigated .According to analysis,we found that in the condition of the depth of detonation remaining unchanged, the influence of air-water surface on shock wave is mainly reflected in reducing the pulse width of incident shock wave and reducing the peak pressure of shock wave with the decrease of sounding depth. The height of water column produced by the same TNT explosive on the air-water surface increases with the decrease of the detonation depth. At the same time, the density distribution near air-water surfaceand the process of water column forming under different detonation depths are qualitatively analyzed, which is also reproduced with three-dimensional numerical simulation method.With the numerical simulation method, the characteristics of the shock wave values are analyzed and certify that the model has better calculation accuracy compared with the empirical formula,and the process of underwater explosion near air-water surface is also represented.
2021,18(1):1-6
,DOI: 10.19951/j.cnki.cslgdxxbzkb.2021.01.001
Abstract:
In order to study the interaction effect between embedded strain sensor and asphalt mixture, the finite element model of beam specimen embedded with strain sensor under four-point bending loading condition was established by using ABAQUS finite element software. The effects of load size, sensor pullrod length and sensor encapsulating material modulus on mechanical response and stress concentration of asphalt concrete beam specimen and sensor were analyzed. The results show that after the sensor is embedded in the asphalt mixture beam specimen, the stress concentration phenomenon occurs in the beam specimen, which is located in the asphalt mixture contacting with the sensor flange. But the stress concentration coeficient is small, the maximum value is only 2.95. The sensor also has the stress concentration phenomenon in the pulrod, and the maximum value of the stress concentration coeficient is 26.83, which is much higher than that of the beam specimen.
In order to study the interaction effect between embedded strain sensor and asphalt mixture, the finite element model of beam specimen embedded with strain sensor under four-point bending loading condition was established by using ABAQUS finite element software. The effects of load size, sensor pullrod length and sensor encapsulating material modulus on mechanical response and stress concentration of asphalt concrete beam specimen and sensor were analyzed. The results show that after the sensor is embedded in the asphalt mixture beam specimen, the stress concentration phenomenon occurs in the beam specimen, which is located in the asphalt mixture contacting with the sensor flange. But the stress concentration coeficient is small, the maximum value is only 2.95. The sensor also has the stress concentration phenomenon in the pulrod, and the maximum value of the stress concentration coeficient is 26.83, which is much higher than that of the beam specimen.
2021,18(1):87-94
,DOI: 10.19951/j.cnki.cslgdxxbzkb.2021.01.011
Abstract:
In view of the uncertainty of the parameters of the pile foundation model,a method of parameter inversion identification for pile foundation model was proposed.Taking the measuring point sand the tapping points as noise factors,comprehensively considering the impact of the acceleration response on the inversion results at different measuring points and tapping conditions in the model,using multiple information fusion,the score values were merged into aunique parameter inversion to identify the targetre sponse value.The research results show that the inversion curve obtained by this method has a good fit with the simu- lation curve.This study provides a reference to parameter in version identification for the pile foundation model.
In view of the uncertainty of the parameters of the pile foundation model,a method of parameter inversion identification for pile foundation model was proposed.Taking the measuring point sand the tapping points as noise factors,comprehensively considering the impact of the acceleration response on the inversion results at different measuring points and tapping conditions in the model,using multiple information fusion,the score values were merged into aunique parameter inversion to identify the targetre sponse value.The research results show that the inversion curve obtained by this method has a good fit with the simu- lation curve.This study provides a reference to parameter in version identification for the pile foundation model.
Copyright Information
- ParentUnit：Hunan Provincial Department of Education
- Organizers：Changsha University of Science & Technology
- Editor in chief：ZHENG Jianlong
- Executive Editor：ZHAO Bing
- PublishHouse：Editorial Office of Journal of Changsha University of Science & Technology (Natural Science)
- Printing：Hunan High-speed Printing Co., Ltd.
- Domestic release：湖南省邮政报刊发行局
- CN：43-1444/N
- ISSN：1672-9331
- PostID：42-304
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