考虑初始组构影响的饱和粘土动力特性及微观机理研究

作为众多重大工程地基的软粘土在循环荷载作用下会产生过大变形和失稳，究其主要原因之一是对软粘土动力特性缺乏全面认识。本项目拟通过弯曲元、共振柱联合扭剪系统以及变围压动三轴试验，深入研究考虑初始组构影响的饱和粘土动力特性，揭示初始组构对饱和粘土动剪切模量及循环荷载作用下变形特性的影响规律；通过扫描电镜及图像处理分析技术，研究不同初始组构饱和粘土在动剪切模量试验和循环加载试验中的微观结构参数及其演化规律，从微观角度揭示初始组构对饱和粘土动剪切模量及循环荷载作用下变形发展影响的机理；对不同初始组构饱和粘土的宏观动力特性与微观结构参数进行相关性分析，获取可以反映初始组构对宏观动力特性影响的最优微观结构参数，建立考虑初始组构影响的饱和粘土动剪切模量模型和考虑初始组构影响的循环荷载作用下饱和粘土累积变形模型。本项目的实施对于深入认识粘土基本特性，促进宏观特性与微观结构相结合的研究具有重要的科学意义。

Many major projects built on soft clay will yield larger settlement and instability under cyclic loading. One of the main reasons is lack of recognizing the dynamic properties of complex soft clay. In this project, bender element test, resonant column test with rotational shear module, and variable confining pressure triaxial apparatus are employed to deeply investigate the effect of initial fabric on dynamic properties for saturated clay and reveal the rules for the effect of initial fabric on dynamic shear modulus and permanent deformation under cyclic loading. Scanning Electron Microscope and image analysis are used to study the microstructure and micro-parameters change for different fabric clay in each test. This project attempts to reveal the micro-mechanism for the effect of fabric on dynamic shear modulus and permanent deformation under cyclic loading. Relative analysis between the dynamic properties and micro-parameters is made to obtain the micro-parameters which could obviously reflect the effect of fabric on dynamic properties. Based on the micro-parameters, the dynamic shear modulus model and the predictive model for permanent deformation under cyclic loading are established with considering the effect of fabric. This project will make great contribution to the study of clay properties and will improve the development for macro-micro incorporation.