Long-term cyclic train loading can cause settlement and deformation of the roadbed,affecting the normal operation of trains.In order to investigate the strain pattern of reinforced sandy soil under train loading,a ser...Long-term cyclic train loading can cause settlement and deformation of the roadbed,affecting the normal operation of trains.In order to investigate the strain pattern of reinforced sandy soil under train loading,a series of dynamic triaxial tests were carried out using multi-stage loading,focusing on the effects of the number of reinforcement layers,the confining pressure,and the mesh size of the geogrid on the accumulated plastic strain of reinforced sandy soil.Moreover,prediction models were proposed.The test results show that:1)The cumulative plastic strain versus vibration times of the specimens under different reinforcement layers exhibited three stages,namely,the rapid development stage,the rate transformation stage and the stability stage;2)The cumulative plastic strain decreases with increasing the number of reinforcement layers,but the magnitude of the effect of reinforcement on the cumulative plastic strain decreases with increasing the number of reinforcement layers,increasing the perimeter pressure and decreasing the mesh size of the geogrid have similar effects on the cumulative plastic strain pattern as increasing the number of reinforcement layers;3)Combined with the cumulative plastic strain law,a comprehensive model is proposed and the coefficient of determination is greater than 0.99.Furthermore,The cumulative plastic strain evolution law can be effectively predicted.The significance of parameters A,B and C is analyzed in detail.This study can provide theoretical references for further understanding of the deformation characteristics and settlement prediction of railway subgrades.展开更多
The resilient modulus,accumulated plastic strain,peak shear stress,and critical shear stress are the elastoplastic behaviors of frozen sand–concrete interfaces under cyclic shear loading.They reflect the bearing capa...The resilient modulus,accumulated plastic strain,peak shear stress,and critical shear stress are the elastoplastic behaviors of frozen sand–concrete interfaces under cyclic shear loading.They reflect the bearing capacity of buildings(e.g.highspeed railways)in both seasonal frozen and permafrost regions.This study describes a series of direct shear experiments conducted on frozen sand–concrete interfaces.The results indicated that the elastoplastic behaviors of frozen sand–concrete interfaces,including the resilient modulus,accumulated plastic strain,and shear strength,are influenced by the boundary conditions(constant normal loading and constant normal height),initial normal stress,negative temperature,and cyclic-loading amplitude.The resilient modulus was significantly correlated with the initial normal stress and negative temperature,but not with the cyclic-loading amplitude and loading cycles.The accumulated plastic shear strain increased when the initial normal stress and cyclic-loading amplitude increased and the temperature decreased.Moreover,the accumulated plastic shear strain increment decreased when the loading cycles increased.The accumulated direction also varied with changes in the initial normal stress,negative temperature,and cyclic-loading amplitude.The peak shear stress of the frozen sand–concrete interface was affected by the initial normal stress,negative temperature,cyclic-loading amplitude,and boundary conditions.Nevertheless,a correlation was observed between the critical shear stress and the initial normal stress and boundary conditions.The peak shear stress was higher,and the critical shear stress was lower under the constant normal height boundary condition.Based on the results,it appears that the properties of frozen sand–concrete interfaces,including plastic deformation properties and stress strength properties,are influenced by cyclic shear stress.These results provide valuable information for the investigation of constitutive models of frozen soil–structure interfaces.展开更多
基金Sponsored by National Natural Science Foundation of China(Grant No.42077249)Innovation an Entrepreneurship Training Program for College Students of Hefei University of Technology(Grant Nos.S202410359131 and X202410359244).
文摘Long-term cyclic train loading can cause settlement and deformation of the roadbed,affecting the normal operation of trains.In order to investigate the strain pattern of reinforced sandy soil under train loading,a series of dynamic triaxial tests were carried out using multi-stage loading,focusing on the effects of the number of reinforcement layers,the confining pressure,and the mesh size of the geogrid on the accumulated plastic strain of reinforced sandy soil.Moreover,prediction models were proposed.The test results show that:1)The cumulative plastic strain versus vibration times of the specimens under different reinforcement layers exhibited three stages,namely,the rapid development stage,the rate transformation stage and the stability stage;2)The cumulative plastic strain decreases with increasing the number of reinforcement layers,but the magnitude of the effect of reinforcement on the cumulative plastic strain decreases with increasing the number of reinforcement layers,increasing the perimeter pressure and decreasing the mesh size of the geogrid have similar effects on the cumulative plastic strain pattern as increasing the number of reinforcement layers;3)Combined with the cumulative plastic strain law,a comprehensive model is proposed and the coefficient of determination is greater than 0.99.Furthermore,The cumulative plastic strain evolution law can be effectively predicted.The significance of parameters A,B and C is analyzed in detail.This study can provide theoretical references for further understanding of the deformation characteristics and settlement prediction of railway subgrades.
基金supported by the National Natural Science Foundation of China(No.41731281)the Key Foundation of Guangdong Province(No.2020B1515120083),China。
文摘The resilient modulus,accumulated plastic strain,peak shear stress,and critical shear stress are the elastoplastic behaviors of frozen sand–concrete interfaces under cyclic shear loading.They reflect the bearing capacity of buildings(e.g.highspeed railways)in both seasonal frozen and permafrost regions.This study describes a series of direct shear experiments conducted on frozen sand–concrete interfaces.The results indicated that the elastoplastic behaviors of frozen sand–concrete interfaces,including the resilient modulus,accumulated plastic strain,and shear strength,are influenced by the boundary conditions(constant normal loading and constant normal height),initial normal stress,negative temperature,and cyclic-loading amplitude.The resilient modulus was significantly correlated with the initial normal stress and negative temperature,but not with the cyclic-loading amplitude and loading cycles.The accumulated plastic shear strain increased when the initial normal stress and cyclic-loading amplitude increased and the temperature decreased.Moreover,the accumulated plastic shear strain increment decreased when the loading cycles increased.The accumulated direction also varied with changes in the initial normal stress,negative temperature,and cyclic-loading amplitude.The peak shear stress of the frozen sand–concrete interface was affected by the initial normal stress,negative temperature,cyclic-loading amplitude,and boundary conditions.Nevertheless,a correlation was observed between the critical shear stress and the initial normal stress and boundary conditions.The peak shear stress was higher,and the critical shear stress was lower under the constant normal height boundary condition.Based on the results,it appears that the properties of frozen sand–concrete interfaces,including plastic deformation properties and stress strength properties,are influenced by cyclic shear stress.These results provide valuable information for the investigation of constitutive models of frozen soil–structure interfaces.
