黏性土干缩开裂过程离散元数值模拟

司马军; 蒋明镜; 周创兵

黏性土干缩开裂过程离散元数值模拟 English Version

1. 武汉大学水利水电学院,湖北武汉 430072; 2. 武汉大学土木建筑工程学院,湖北武汉 430072; 3. 同济大学地下建筑与工程系,上海 200092

基金项目: 中国博士后面上基金项目（2012M511669）

详细信息

作者简介:
司马军(1972- )，男，湖北公安人，博士后，副教授，主要从事地基与基础方面的研究与教学工作。E-mail: simajun81@126.com。

中图分类号: TU47
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出版历程
- 收稿日期: 2013-06-06
- 发布日期: 2013-11-24

Numerical simulation of desiccation cracking of clay soils by DEM

1. School of Water Conservancy and Hydropower Engineering, Wuhan University, Wuhan 430072, China; 2. School of Civil Engineering, Wuhan University, Wuhan 430072, China; 3. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China

摘要

摘要: 在自然环境中,干缩裂缝是导致土质堤坝、土坡及黏土衬垫等产生渐进破坏的重要因素之一,亟待发展有效的定量研究手段来揭示黏性土干缩裂缝演化的力学机制。为此,基于已有的黏性土干缩机理建立了离散元模型,模型中颗粒半径、颗粒胶结接触参数均随含水率的变化而变化；进而采用PFC^3D软件模拟了圆形薄层黏性土试样在粗糙边界条件下干缩裂缝的产生及扩展过程,采用图像技术定量分析了表面裂缝的几何参数,并与室内试验结果进行了对比分析。结果表明,模拟的开裂机制反映了拉应力和内部缺陷的共同作用；模拟的裂缝扩展过程表现出三阶段特征,表面裂缝参数的演化规律与室内试验结果基本一致；边界黏结强度对裂缝形态的影响规律与前人成果吻合。
- 黏性土 /
- 干缩开裂 /
- 裂缝扩展 /
- 离散元
Abstract: In nature, desiccation cracks are one of the major factors to cause the progressive failure of clay dams, soil slopes and clay liners. So it is urgent to develop the effective approach to study the mechanism of desiccation cracking. For this sake, a new DEM model based on the shrinkage mechanism of clay soils is developed. In the model, the radius, bond strength and stiffness of the grains are all varied with the water content, and the parameters are determined by matching the experimental data. Then, the initiation and propagation of desiccation cracks in a thin circular clay layer with rough boundaries are simulated using the software of PFC^3D. And the geometric parameters of surface cracks are quantified using the image analysis techniques to be compared with the experimental observations. The conclusions are drawn as follows: the simulated cracking mechanism includes the effects of tensile stress and flaws in the sample; the procedure of crack propagation obtained from DEM presents the character of three stages, and the evolution curves of crack parameters are similar to those from laboratory experiments; and the effect laws of the soil-base cohesion on the crack patterns are also in agreement with the results in literatures.
- clay soil /
- desiccation crack /
- crack propagation /
- DEM

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参考文献(23)

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