基于粒间接触关系的饱和砂土液化特性研究  

Study on Liquefaction Characteristics of Saturated Sand Based on Inter-particle Contact

作　　者：周恩全[1] 姚缘 王龙 卜春尧 伊思航 ZHOU Enquan;YAO Yuan;WANG Long;BU Chunyao;YI Sihang(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang 212013,China;School of Mechanical Engineering,Jiangnan University,Wuxi 214122,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China)

机构地区：[1]江苏大学土木工程与力学学院,江苏镇江212013 [2]江南大学机械工程学院,江苏无锡214122 [3]中国地震局地球物理研究所,北京100081

出　　处：《防灾减灾工程学报》2024年第2期450-458,共9页Journal of Disaster Prevention and Mitigation Engineering

基　　金：江苏省自然科学基金项目(BK20210479);南京市交通运输科技项目(2022)资助。

摘　　要：为了研究饱和砂土的液化机理,通过等体积加载的方式建立了循环荷载下饱和砂土动力响应的颗粒流计算模型,研究了饱和砂土在不同围压和加载幅值下的动力响应,探讨了颗粒间力链的发展特性,并从Shannon熵、Boltzmann熵以及Clausius熵的基本关系入手,建立基于粒间接触力链的饱和砂土颗粒熵计算方法,分析了颗粒熵发展特性。结果表明:饱和砂土初始总力链主要受围压的影响,围压越大,初始总力链越多;循环荷载下饱和砂土颗粒间力链总数逐渐降低,且强力链持续向中、弱力链转换;循环荷载下饱和砂土颗粒熵表现出先升高后降低的二阶段特性,围压和加载幅值对颗粒熵峰值无明显影响,各工况的颗粒熵峰值均为0.92;定义颗粒熵峰值为相变颗粒熵,相变颗粒熵时的饱和砂土表现出固液临界态的力学特征,指示了饱和砂土由固态向往返液化状态转变的临界点。In order to study the liquefaction mechanism of saturated sand,a particle flow calculation model was developed to investigate its dynamic response under cyclic loading using isochoric loading.The study examined the dynamic response of saturated sand under different confining pressures and loading amplitudes,exploring the development characteristics of inter-particle force chains.Using the basic relationships of Shannon entropy,Boltzmann entropy,and Clausius entropy,a method for calcu-lating particle entropy in saturated sand was established based on inter-particle force chains.The devel-opment characteristics of particle entropy in saturated sand were analyzed.The results showed that the total number of initial force chains in saturated sand was primarily influenced by confining pressure and increased with higher pressure.Under cyclic loading,the total number of force chains between saturat-ed sand particles gradually decreased,with strong force chains transitioning to medium and weak force chains.The particle entropy of saturated sand exhibited a two-phase characteristic,initially increasing and then decreasing.Confining pressure and loading amplitude had no significant effect on the particle entropy peak value,which was 0.92 under different cases.The peak value of particle entropy was de-fined as the phase-change particle entropy.The saturated sand with phase-change particle entropy showed mechanical characteristics at the solid-liquid critical state,indicating the transition of saturated sand from a solid state to a cyclic liquefaction state.

关 键 词：饱和砂土 液化 力链 颗粒熵 

分 类 号：TU43[建筑科学—岩土工程]