砂土液化大变形的热力学机理与本构模型研究

项目名称： 砂土液化大变形的热力学机理与本构模型研究

项目编号： No.51408333

项目类型： 青年科学基金项目

立项/批准年度： 2015

项目学科： 建筑科学

项目作者： 宋世雄

作者单位： 清华大学

项目金额： 25万元

中文摘要： 饱和砂土地震液化大变形问题，是岩土工程抗震领域研究的重点和难点之一。本研究采用非平衡态热力学方法，以饱和砂土为研究对象。首先，将饱和砂土简化为固液两相连续介质，构建其热力学理论框架，得到砂土液化大变形行为的控制偏微分方程组；其次，探索合理的自由能和迁移系数模型，再现砂土液化大变形的基本规律，建立其与热力学模型参数之间的内在联系，标定模型参数；以张建民等的大量的试验数据为基础，再辅助开展一系列复杂应力路径试验和砂土材料声学、蠕变试验，检验模型参数的正确性；采用COMSOL Multiphysics 软件进行砂土地基震动液化行为分析。旨在探究和揭示不同条件下的砂土动力学行为及其内在规律，发展和完善计算模型和方法，以期丰富饱和砂土液化问题的动力学理论体系，深化其热力学理论基础，为饱和砂土地震液化大变形分析和预测提供更加系统、全面和科学的理论依据。

中文关键词： 非平衡态热力学；饱和砂土；流变；液化大变形；本构模型

英文摘要： Study on liquefaction and large post-liquefaction deformation of saturated sand is one of important and difficult topics in research on soil dynamics and geotechnical earthquake engineering. Based on the non-equilibrium thermodynamics, the proposed research project focuses on the saturated sand. The main contents are: firstly, considering the saturated sand as a solid-liquid two-phase continuous medium, and constructing its theoretical framework of non-equilibrium thermodynamics, to get the partial differential equations that control the liquefaction and large post-liquefaction deformation behavior of it; secondly, exploring reasonable free energy model and transport coefficient model, reproducing the liquefaction and large post-liquefaction deformation behavior of saturated sand, calibrating right parameters, providing the constitutive relation of sand under the seismic load; thirdly, based on large amounts of experimental data of Zhang Jianmin, as well as a series of complex stress path tests, acoustics tests, creep tests and relaxation tests, verifying the validity of the model; finally, using COMSOL Multiphysics software to analyze the liquefaction behavior of sandy soil foundation under the seismic load. The research project aims to explore and reveal the soil dynamics behavior and its inherent laws under d

英文关键词： non-equilibrium thermodynamics；saturated sand；rheological；large post-liquefaction deformation；constitutive model