RTC路径下粉质粘土平面应变三轴试验研究及剑桥模型的修正

岩土类材料宏观力学特性有强烈的应力路径依赖性，不同应力路径下材料所表现出的应力应变特性存在较大的差异。对于实际工程中存在的卸荷路径工况，目前通常的做法是通过加载的试验方法确定岩土体力学参数和本构模型，这对于实际工程中的卸载路径工况可能会存在较大误差。因此，从实际下程出发，针对深基坑开挖时典型的侧向卸荷工况进行分析。利用多路径平面应变三轴仪对黄石青龙山麓粉质粘土进行了常规路径下平面应变三轴固结排水剪切试验（CTC路径）和减围压平面应变固结排水剪切试验（RTC路径），对比分析2种应力路径下的试验现象，描述了二者的差异性，重点分析了RTC路径下试样所表现出来的力学特性。基于剑桥模型框架的前提下，推导出了基于本文材料的修正剑桥模型方程，为数值分析奠定了基础。

Silty Clay Plane Strain Triaxial Test under RTC Path and Modified Cam- clay Model

The character of geomaterials is affected by stress path remarkablely. Under different stress paths, the stress - strain characteristics of geomaterials are different. For the unloading path, the physical parameters and constitutive model were usually determined by loading test paths which may result in larger error. Therefore, deep excavation of the lateral unloading condition was analyzed from the actual project. The plane strain triaxial tests of CTC and RTC paths on the silty clay of Qinglong Piedmont were carried on. Then, the phenomenon under the two stress paths was compared with each other. And the differences of mechanics characters between the two paths were described. The mechanical properties in the RTC stress path were ana- lyzed mainly. Based on the Cam -Clay model framework, a modified Cam -clay yield equation was derived for this material. It is shown that the equation can be used for the numerical analysis.