红砂岩粗粒土动力试验及颗粒破碎模型研究  

Dynamic tests and particle breakage model of red sandstone coarse grained soil

作　　者：龙尧 张同文 张家生[2] 肖源杰 LONG Yao;ZHANG Tongwen;ZHANG Jiasheng;XIAO Yuanjie(School of Railway Engineering,Hunan Technical College of Railway High-speed,Hengyang 421002,China;School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]湖南高速铁路职业技术学院铁道工程学院,湖南衡阳421002 [2]中南大学土木工程学院,长沙410075

出　　处：《振动与冲击》2023年第3期270-279,共10页Journal of Vibration and Shock

基　　金：国家自然科学基金(52178443,51878673,U1734208,U1934209);国家重点研发计划(2019YFC1904704);重载铁路工程结构教育部重点实验室开放基金(2021JZZ01,2021JZZ02);湖南省教育厅职教高地重点项目(ZJGD2021144);湖南省教育厅科学研究项目(22B0958);湖南省科学技术厅项目(S2021JJSSLH0088)。

摘　　要：铁路路基建设需要经过泛红砂岩地区,红砂岩路基的稳定性对列车安全起到至关重要的作用。为研究列车荷载对红砂岩粗粒土动力特性以及颗粒破碎的影响,采用室内大型动静三轴试验系统,开展动力荷载下的红砂岩试样动力响应测试,分析了粒径大小、加载次数对轴向应变、动力软化以及颗粒破碎的影响。根据动力破碎三轴试验结果,构建了动力作用下的颗粒破碎模型,并对模型进行了验证。研究结果表明:在加载次数一定的条件下,颗粒粒径越大对应的轴向应变越大;颗粒粒径越小,越早完成颗粒破碎及土体结构调整。粗粒土软化曲线呈半对数关系,颗粒粒径越大,软化系数越小。动力荷载下,大粒径颗粒主要演化为下一级粒径颗粒和细小粒径颗粒,破碎形式为研磨,存在一个极限破碎级配。根据动力破碎试验建立了动力破碎的概率密度函数f,构建了动力条件下的颗粒破碎模型。该模型能够较好的模拟动力作用下的颗粒破碎过程。Marsal颗粒破碎率Br与颗粒破碎模型中的死亡率Ps-t呈线性关系。研究结果能为铁路路基工程相关设计提供一定的理论参考价值。Railway subgrade construction needs to pass through pan red sandstone area, and the stability of red sandstone subgrade plays a vital role in train safety. Here, to study effects of train load on dynamic characteristics and particle breakage of red sandstone coarse grained soil, a large indoor dynamic and static triaxial test system was used to conduct dynamic response testing of red sandstone specimens under dynamic load, and effects of particle size and loading times on axial strain, dynamic softening and particle breakage were analyzed. According to the results of dynamic crushing triaxial tests, a particle breakage model under dynamic action was established and verified. The results showed that under the condition of definite loading times, the larger the particle size, the larger the axial strain;the smaller the particle size is, the earlier the particle crushing and soil body structure adjustment are completed;softening curve of coarse grained soil reveals a semi-logarithmic relation;the larger the particle size, the smaller the softening coefficient;under dynamic load, large size particle mainly evolves into next smaller level particle size and small particle size, crushing form is grinding, and there is a limit crushing gradation;based on dynamic crushing tests, the probability density function f of dynamic crushing is established, and particle crushing model under dynamic conditions is established;this model can better simulate particle crushing process under dynamic action;there is a linear relation between Marsal particle breakage ratio Brand mortality rate Ps-tin particle breakage model;the study results can provide a certain theoretical reference for relevant design of railway subgrade engineering.

关 键 词：红砂岩 粗粒土 铁路工程 动力试验 颗粒破碎模型 

分 类 号：TU452[建筑科学—岩土工程]