界面不规则多层场地砂土地震液化研究

项目名称： 界面不规则多层场地砂土地震液化研究

项目编号： No.51308512

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 建筑科学

项目作者： 单振东

作者单位： 中国地震局工程力学研究所

项目金额： 25万元

中文摘要： 我国大部分城市位于平原地区，场地一般为界面不规则的多层土体。地层结构形式对砂土初始应力状态、排水条件以及地震中动荷载形式等均有重要影响。然而，由于地层结构形式复杂多变，现行的地基液化危害性评价体系中并没有考虑这一影响因素。本项目拟通过超重力离心机试验和数值模拟，揭示界面不规则地层结构对场地砂土层液化的影响机制。首先，基于Biot饱和多孔介质理论，研究界面不规则多层饱和多孔介质稳态响应，分析典型界面不规则多层场地中土单元体动应力路径。其次，通过室内单元体试验，研究具有不同初始应力状态的砂土在典型动应力路径作用下的动力特性。开展超重力离心模型试验和数值模拟，再现场地砂土层液化触发及时空演化全过程，揭示界面不规则地层结构对场地砂土层液化的影响机制，明确地层结构形式与场地破坏模式间关系。最终，提出实用的场地液化危害评价方法及工程处置对策。

中文关键词： 砂土液化；地层结构；多相介质；轴对称荷载；解析解

英文摘要： Most cities in China are located in plains, and the stratum structures usually have irregular surfaces, which have significant influence on the initial stress state of the soil, the drainage condition and dynamic load during earthquake. However, due to the complexity of the stratum structure, this influence is not considered in the current method for the hazard assessment of sand liquefaction. This project aims to reveal the influence mechanism of layered ground with irregular surfaces on the sand liquefaction through the numerical simulation and high gravity centrifuge model test. First, based on the Biot theory, the solution for the dynamic response of a typical saturated multi-layered soil with irregular interfaces are given. Using this solution, the dynamic stress paths in a multi-layered soil with typical stratum structure are studied. Second, through laboratory tests, the dynamic behavior of sand with different initial stress states and typical dynamic stress paths is studied. The numerical simulation technique and high gravity centrifuge model test are used to reproduce the space-time evolutionary process of the sand liquefaction in multi-layered soil. We try to reveal the influence mechanism of the stratum structure on the sand liquefaction and establish the relationship between the stratum structure and

英文关键词： Sand liquefaction；Soil layer construction；Multiphase medium；Axisymmetric load；Analytical solution