高频循环荷载作用下砂土抗剪强度试验研究  

Experimental Study on Shear Strength of Sand under High-frequency Cyclic Loading

作　　者：陕耀[1,2] 陈平 周顺华 叶伟涛[1,2] 代宁 SHAN Yao;CHEN Ping;ZHOU Shunhua;YE Weitao;DAI Ning(Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety,Tongji University,Shanghai 201804,China;Key Laboratory of Road and Traffic Engineering of the Ministry of Education,Shanghai 201804,China;China Railway Urban Development Investment Group Co.,Ltd.,Chengdu 610218,China)

机构地区：[1]同济大学道路与交通工程教育部重点实验室,上海201804 [2]上海市轨道交通结构耐久与系统安全重点实验室,上海201804 [3]中铁城市发展投资集团有限公司,四川成都610218

出　　处：《铁道学报》2023年第8期147-155,共9页Journal of the China Railway Society

基　　金：国家自然科学基金(51761135109);上海市科技计划项目(21142200400)。

摘　　要：路基填料的力学性质在车致振动下会发生显著变化,既有车速为350 km/h的高速铁路路基动力异常现象正逐步显现。当车速接近400 km/h甚至更高时,高速铁路路基振动响应的高频成分更为显著,探究高频振动下散体材料强度的变化规律有助于揭示路基潜在的动力隐患。为研究高频振动作用下散体材料的强度变化规律,选用材料参数变异性小的平潭标准砂进行一系列三轴试验,将试样通过静力加载至近临界状态后附加高频循环荷载,研究高频循环荷载作用下砂土残余抗剪强度特性,及振动强度、有效围压、初始相对密实度、含水率、振动频率等因素对残余抗剪强度损失的影响。试验结果表明:附加高频循环荷载会引起砂土试样残余抗剪强度的损失,即静态与振动稳定后残余抗剪强度之差。The mechanical properties of subgrade fillers will change significantly under vehicle-induced vibration,and the dynamic anomalies of the subgrade of existing high-speed railways with the operation speed of 350 km/h are gradually emerging.At the train speed of 400 km/h or above,the high-frequency component of the vibration response of the high-speed railway subgrade is more significant.Hence,exploring the variation law of the strength of the bulk material under high-frequency vibration is helpful to reveal the potential dynamic hazards of the subgrade.In order to investigate the change law of the strength of bulk material under high-frequency vibration,the Pingtan sand with low parameter variability was used to conduct a series of triaxial tests.The specimens were firstly statically loaded to a near critical state before additional high-frequency cyclic load was added to the specimens,to study the characteristics of the residual shear strength of the sand under high-frequency cyclic load,as well as the impact of factors such as vibration intensity,effective confining pressure,initial relative density,moisture content,and vibration frequency on the loss of residual shear strength.The results show that the additional high-frequency cyclic load will cause the loss of the residual shear strength of the sand specimens,which is the difference from the residual shear strength between static load and high-frequency cyclic load.

关 键 词：高速铁路路基 高频循环荷载 砂土 三轴压缩试验 残余抗剪强度损失 

分 类 号：TU411.8[建筑科学—岩土工程] U213.1[建筑科学—土工工程]