非饱和结构性黄土侧限压缩和湿陷试验三维离散元分析

李涛; 蒋明镜; 张鹏

doi:10.11779/CJGE2018S1007

非饱和结构性黄土侧限压缩和湿陷试验三维离散元分析 English Version

李涛^{1, 2, 4},
蒋明镜^1,2,3,4, ,,
张鹏^{1, 2}

1. 同济大学土木工程防灾国家重点实验室,上海 200092;
2. 同济大学土木工程学院地下建筑与工程系,上海 200092;
3. 同济大学岩土及地下工程教育部重点实验室,上海 200092;
4. 天津大学土木工程系,天津 300072

基金项目: 国家自然科学基金项目（51579178）; 土木工程防灾国家重点实验室自主研究课题基金项目（SLDRCE14-A-04）; 国家自然科学基金重点项目（51639008）

详细信息

作者简介:
李涛(1985- ),男,博士研究生,主要从事结构性土宏微观力学性质研究。E-mail：letllejn@163.com。

通讯作者:
蒋明镜，E-mail：mingjing.jiang@tongji.edu.cn

中图分类号: TU43
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出版历程
- 收稿日期: 2018-02-23
- 发布日期: 2018-08-24

DEM analyses of oedometer and wetting tests on unsaturated structured loess

LI Tao^{1, 2, 4},
JIANG Ming-jing^1,2,3,4, ,,
ZHANG Peng^{1, 2}

1. State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China;
2. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China;
3. Key Laboratory of Geotechnical & Underground Engineering. Ministry of Education, Tongji University, Shanghai 200092, China;
4. School of Civil Engineering, Tianjin University, Tianjin 300072, China

摘要

摘要: 为了研究非饱和结构性黄土在侧限状态下受竖向荷载和增湿作用的宏微观力学性质,对非饱和重塑和结构性黄土侧限压缩和湿陷试验开展了三维离散元模拟分析。首先通过引入颗粒吸引力考虑黄土颗粒间范德华力和毛细力作用,引入胶结考虑结构性黄土颗粒间化学胶结作用,建立结构性黄土三维接触模型;然后采用分层欠压法并考虑颗粒间范德华力制成松散均匀的黄土离散元试样,在试样中施加毛细力模拟黄土的非饱和性,施加胶结模拟黄土的结构性;最后选择合适的接触模型参数,对试样施加分级竖向荷载并在多级荷载下进行了增湿试验分析。结果表明：离散元模拟能够再现黄土室内侧限压缩和湿陷试验的主要力学性质,如重塑黄土的屈服应力和结构性土的结构屈服应力随含水率的减小而增加,重塑黄土和结构性黄土单线法增湿变形结果基本与双线法结果相同。胶结破坏分析表明,结构性黄土离散元试样的胶结破坏存在阈值平均应力;增湿后达到的胶结破坏数与相同竖向压力下的饱和土胶结破坏数相差不大（单双线法相同）;湿陷体应变与胶结破坏数量密切相关。
- 非饱和土 /
- 结构性土 /
- 离散单元法 /
- 侧限压缩试验 /
- 湿陷试验
Abstract: To investigate the macroscopic and microscopic mechanical performances of unsaturated structured loess, three-dimensional discrete element analyses of oedometer and wetting tests on the unsaturated remolded and structured loess are performed. Firstly, interparticle adhesive force is incorporated to consider the effect of van der Waals attractions and capillary forces, and bonds are introduced in the 3D contact model to calculate the influence of chemical bond. Then a loose and homogeneous DEM sample is produced by the multi-layer under-compaction method (UCM) and the installation of van der Waals forces. The capillary forces and bonds are installed to the contacts to simulate the unsaturated and structural properties, respectively. After parameter determination, stepwise loads are applied and then the sample is wetted at different vertical loads. The simulation reproduces the main mechanical behavior of oedometer and wetting tests on structured loess. Concerning the bond breakage, there is a threshold of vertical stress in the oedometer tests. The bond breakage number of the sample subjected to loading-wetting is similar to the number of the sample under wetting-loading sequence. The wetting-induced volumetric strain is affected by the bond breakage.
- unsaturated soil /
- structured soil /
- discrete element method /
- oedometer test /
- wetting test

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参考文献(19)

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