不同应力路径下砾石土力学特性的宏细观研究  

MACRO-MESO RESEARCH ON MECHANICAL BEHAVIOR OF A GRAVELLY SOIL UNDER VARIOUS STRESS PATHS

作　　者：周健[1,2] 王子寒[1,2] 张姣[3] 邓益兵[4] 

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092 [3]上海城市管理职业技术学院土木工程与交通学院,上海200432 [4]上海海事大学海洋科学与工程学院,上海201306

出　　处：《岩石力学与工程学报》2013年第8期1721-1728,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金面上项目(41272296);国家自然科学基金青年基金项目(51208294)

摘　　要：利用空心圆柱仪对砾石土进行三轴压缩、扭剪、三轴–扭剪联合3种单调加载路径试验以及应力主轴旋转路径试验。通过设计新型加载路径,实现应力主轴在不同应力水平下往复旋转,并在旋转时保持广义剪应力不变。试验结果表明,随着应力水平的增加,主轴旋转产生的广义剪应变呈现先增大、后减小、再增大的规律;主轴旋转会造成试样强度明显下降,内摩擦角显著减小,其破坏时刻的应力圆位于三轴–扭剪联合加载路径应力圆的内部。对三轴压缩和扭剪2种路径试验进行离散元细观分析,发现扭剪力作用下试样会形成水平滑动面。最后,对应力主轴旋转造成试样强度下降的原因进行分析和讨论。Using the hollow cylinder apparatus, a gravelly soil was tested under triaxial, torsional, triaxial- torsional, and principal stress axes rotational paths. A new loading path was designed to achieve principal axes rotation under various stress levels and constant generalized shear stress during rotating. It is shown that, with the stress level increasing, the generalized shear strain due to principal axes rotation increases first, and then decreases, and increases again. The principal stress axes rotation leads to strength decline and friction angle decrease. The stress circle at failure locates in the interior part of that in triaxial-torsional test. The triaxial and torsional tests were simulated numerically by distinct element method. The results show that the horizontal slip surface is developed under torsional force. The reasons for strength decline due to principal axes rotation are also discussed.

关 键 词：土力学 颗粒流程序 细观 应力主轴旋转 应力路径 粗粒料 

分 类 号：TU443[建筑科学—岩土工程]