非饱和结构性黄土双轴湿陷试验的离散元分析  

Analyses of Collapsible Behavior of Unsaturated Structural Loess in Biaxial Wetting Test by Distinct Element Method

作　　者：蒋明镜[1,2] 胡海军[3] 李涛[1,2] 

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]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《地下空间与工程学报》2016年第4期1110-1116,共7页Chinese Journal of Underground Space and Engineering

基　　金：国家杰出青年基金(51025932);国家自然科学基金(51579178);土木工程防灾国家重点实验室项目(SLDRCE14-A-04)

摘　　要：为了分析结构性黄土在复杂应力路径(非侧限压缩路径)下浸水和加荷的次序对黄土湿陷变形的影响以及探讨黄土在双轴剪切和浸水时粒间胶结破坏行为,本文应用分层欠压法制备出非饱和结构性黄土离散元试样,进行了单线法(不同增湿路径:一次增湿、逐步增湿)和双线法双轴数值湿陷试验。结果表明:单线法在某偏应力水平下浸水所得轴向湿陷应变大于双线法;当增湿偏应力大于增湿后试样的强度时会产生湿陷破坏。逐步增湿引起的体积变形小于一次增湿试验;逐步增湿比一次增湿胶结破坏点数量少。In order to investigate the influence of wetting and loading sequence on loess collapsible behavior under complex stress paths（ not oedometer path） and to analyze the bond breakage processes of structural loess subjected to biaxial compression and wetting,the authors carried out loading-wetting biaxial tests（ under different wetting procedures,i.e. quick wetting and gradual wetting） and wetting-loading biaxial tests for numerical structural loess which was generated by Multi-layer Under-compaction Method（ UCM）. The following conclusions can be drawn. The axial strain induced by wetting under a stress level was larger than that of wetting-loading sample. Wetting under a stress level which was larger than the shear strength of saturated（ i.e. wetting-loading path） sample may cause failure. The volumetric deformation induced by the gradual wetting was smaller than that induced by quick wetting and the bond breakage number was less.

关 键 词：结构性黄土 离散单元法 双线法/预湿法 单线法/后湿法 湿陷性 

分 类 号：TU434[建筑科学—岩土工程]