为研究冲击荷载作用下冻结水泥土损伤演化及能量衍生流动特性规律,进行了不同冲击气压和冻结温度条件下的冻结水泥土霍普金森压杆(Split Hopkinson Pressure Bar, SHPB)冲击试验,并结合ABAQUS有限元软件进行数值模拟,分析冻结水泥土的...为研究冲击荷载作用下冻结水泥土损伤演化及能量衍生流动特性规律,进行了不同冲击气压和冻结温度条件下的冻结水泥土霍普金森压杆(Split Hopkinson Pressure Bar, SHPB)冲击试验,并结合ABAQUS有限元软件进行数值模拟,分析冻结水泥土的动应力-应变,能量吸收、耗散及动态弹性模量曲线,解释了冻结水泥土的损伤破坏机理。结果表明:高冲击气压和低冻结温度是冻结水泥土试样受荷后破碎程度加剧的主要因素;冲击荷载作用下冻结水泥土内部能量衍生流动可划分为能量吸收、扩展和耗散3个阶段,且能量吸收、扩展阶段的冲击气压及冻结温度效应显著。研究成果可为动力荷载作用下冻结水泥土的加固工程提供理论基础。展开更多
Frozen moraine soils are widely distributed across the Tianshan Mountains,the Qinghai-Tibetan Plateau,and other high-altitude regions.Engineering activities,particularly blasting,often induce degradation of the soil m...Frozen moraine soils are widely distributed across the Tianshan Mountains,the Qinghai-Tibetan Plateau,and other high-altitude regions.Engineering activities,particularly blasting,often induce degradation of the soil microstructure,compromising its mechanical integrity and increasing the risk of slope instability and rainfall-triggered debris flows-posing serious threats to infrastructure in cold regions.Previous studies have largely treated frozen soils as homogeneous continua,thereby overlooking key micro-scale processes such as ice-soil interaction,microcrack propagation,and particle breakage.In this study,the dynamic mechanical behavior and microstructural damage mechanisms of frozen moraine soil were systematically investigated under varying temperatures(−5℃,−15℃,and−25℃)and strain rates(50 s^(-1),70 s^(-1),and 90 s^(-1)).Results reveal that both temperature and strain rate significantly influence the dynamic stress-strain response.Energy absorption exhibits a three-stage pattern of increase,stabilization,and decline.At−25℃,increased ice brittleness reduces the peak energy absorption efficiency under impact.To capture the observed nonlinear behavior,a damage-based constitutive model was developed,incorporating coupled effects of impact-induced microcracking,ice-soil interfacial debonding,and particle fracture.The stochastic evolution of interfacial debonding and grain breakage was described using a Weibull statistical framework,linking microstructural deterioration to macroscopic response.The model shows strong agreement with experimental data and accurately simulates key parameters such as peak stress and energy absorption.These findings enhance the understanding of dynamic damage mechanisms in frozen soils and offer a computational tool for the safety assessment and hazard mitigation of engineering structures in cold,high-altitude environments.展开更多
Ice lens initiation is the core issue in understanding the dynamic process of frost heave.However,there are still limitations to find an adequate criterion for describing the formation of ice lens.A series of one-dime...Ice lens initiation is the core issue in understanding the dynamic process of frost heave.However,there are still limitations to find an adequate criterion for describing the formation of ice lens.A series of one-dimensional freezing tests is designed using the particle image velocimetry(PIV)method to monitor the frost heave and ice lens formation.The results show that the conventional parameters,such as displacement and velocity,cannot be used to track the ice lens formation,while the strain can be employed to detect the ice lens formation and investigate the freezing change patterns.This study proposes strain as a new criterion for assessing ice lens initiation,applicable across various soil types and freezing conditions(constant freezing and ramped freezing).The strain change in the region where the ice lens forms is the largest during the freezing process.Additionally,strain curves at the top of the soil samples can reveal different freezing patterns and distinguish the first and second frost heave stages.This newly developed technology enables continuous,non-destructive monitoring of ice lens initiation across diverse conditions and soil types,enhancing data visualization and three-dimensional modeling of freezing parameters while improving traditional methods by directly measuring velocity and strain in frost heave investigations.The study is expected to enhance the research of ice lens criterion and provide a new perspective for monitoring the freezing process.展开更多
文摘为研究冲击荷载作用下冻结水泥土损伤演化及能量衍生流动特性规律,进行了不同冲击气压和冻结温度条件下的冻结水泥土霍普金森压杆(Split Hopkinson Pressure Bar, SHPB)冲击试验,并结合ABAQUS有限元软件进行数值模拟,分析冻结水泥土的动应力-应变,能量吸收、耗散及动态弹性模量曲线,解释了冻结水泥土的损伤破坏机理。结果表明:高冲击气压和低冻结温度是冻结水泥土试样受荷后破碎程度加剧的主要因素;冲击荷载作用下冻结水泥土内部能量衍生流动可划分为能量吸收、扩展和耗散3个阶段,且能量吸收、扩展阶段的冲击气压及冻结温度效应显著。研究成果可为动力荷载作用下冻结水泥土的加固工程提供理论基础。
基金financially supported by the National Key R&D Program of China(2024YFC3012700)National Natural Science Foundation of China(12302499)+1 种基金Key Laboratory of Mountain Hazards and Engineering Resilience,Chinese Academy of Sciences(KLMHER-Z17,KLMHER-T07)National Natural Science Foundation of Fujian Province(Grant No.2024J08074).
文摘Frozen moraine soils are widely distributed across the Tianshan Mountains,the Qinghai-Tibetan Plateau,and other high-altitude regions.Engineering activities,particularly blasting,often induce degradation of the soil microstructure,compromising its mechanical integrity and increasing the risk of slope instability and rainfall-triggered debris flows-posing serious threats to infrastructure in cold regions.Previous studies have largely treated frozen soils as homogeneous continua,thereby overlooking key micro-scale processes such as ice-soil interaction,microcrack propagation,and particle breakage.In this study,the dynamic mechanical behavior and microstructural damage mechanisms of frozen moraine soil were systematically investigated under varying temperatures(−5℃,−15℃,and−25℃)and strain rates(50 s^(-1),70 s^(-1),and 90 s^(-1)).Results reveal that both temperature and strain rate significantly influence the dynamic stress-strain response.Energy absorption exhibits a three-stage pattern of increase,stabilization,and decline.At−25℃,increased ice brittleness reduces the peak energy absorption efficiency under impact.To capture the observed nonlinear behavior,a damage-based constitutive model was developed,incorporating coupled effects of impact-induced microcracking,ice-soil interfacial debonding,and particle fracture.The stochastic evolution of interfacial debonding and grain breakage was described using a Weibull statistical framework,linking microstructural deterioration to macroscopic response.The model shows strong agreement with experimental data and accurately simulates key parameters such as peak stress and energy absorption.These findings enhance the understanding of dynamic damage mechanisms in frozen soils and offer a computational tool for the safety assessment and hazard mitigation of engineering structures in cold,high-altitude environments.
基金supported by the National Natural Science Foundation of China(Grant No.52178376)National Key R&D Program of China(Grant No.2022YFB2603301)Science and Technology Research and Development Program of China Railway Group Limited(Grant No.2022-ZD-13).
文摘Ice lens initiation is the core issue in understanding the dynamic process of frost heave.However,there are still limitations to find an adequate criterion for describing the formation of ice lens.A series of one-dimensional freezing tests is designed using the particle image velocimetry(PIV)method to monitor the frost heave and ice lens formation.The results show that the conventional parameters,such as displacement and velocity,cannot be used to track the ice lens formation,while the strain can be employed to detect the ice lens formation and investigate the freezing change patterns.This study proposes strain as a new criterion for assessing ice lens initiation,applicable across various soil types and freezing conditions(constant freezing and ramped freezing).The strain change in the region where the ice lens forms is the largest during the freezing process.Additionally,strain curves at the top of the soil samples can reveal different freezing patterns and distinguish the first and second frost heave stages.This newly developed technology enables continuous,non-destructive monitoring of ice lens initiation across diverse conditions and soil types,enhancing data visualization and three-dimensional modeling of freezing parameters while improving traditional methods by directly measuring velocity and strain in frost heave investigations.The study is expected to enhance the research of ice lens criterion and provide a new perspective for monitoring the freezing process.
