基于细观力学的土体渗透稳定分析方法研究

Research on Method for Analysis of Stability of Seepage in Soils Based on Meso-Mechanics

讨论了颗粒分析方法的发展现状和力学理论基础,尝试了一种用传统渗流理论确定工程体渗透稳定的薄弱部位,用颗粒分析方法研究其渗透稳定性的新方法。以某水库大坝反滤层的渗透稳定性研究为例,采用商业软件Geostudio2007的Seep模块确定大坝反滤层的最不利部位及其渗透坡降,用反滤层的级配包络曲线和压实密度生成细观分析模型,用宏观模型计算结果作为细观分析的边界条件,最后采用基于离散单元理论的颗粒方法软件PFC研究大坝反滤层的渗透稳定性及其允许渗透坡降。计算结果表明,随着细观模型压力水头的增加,颗粒将产生移动,细观模型内部结构逐渐改变。当压力水头达到阀值时,细观模型中的渗透破坏通道完全形成。揭示了反滤层的安全与否取决于其级配组成、密度和所承受的水头。

The present-day progress of particle analysis method and theoretical base of mechanics are discussed in this paper.The classical seepage theory is tried to determine the weak part of seepage stability of engineering body.Also the particle analysis method is used to study a new method of seepage stability.Taking the filter seepage stability of a dam as the research example,seep module of commercial software Geostudio 2007 is adopted to determine the most unfavorable part and seepage slopes of the dam filter layer.And then,the grading grain size curve of the filter layer and compacted or settled boundary densities are used to produce the module of meso-analysis model.The macro-model is used to calculate the results served as the boundary conditions of meso-analysis.At last,the particle method software PFC based on the dispersion unit theory is adopted to study the seepage stability and allowed seepage slope gradient of the dam filter layer.The calculated results show that with an increase in pressure waterhead of meso-model,the particles will produce the movement and the inner structure in meso-model will change gradually.When the pressure waterhead reaches the threshold values,the seepage destructive passage within the meso-model has completely formed.This can indicate whether the safety of filter layer depends on the components of grading,density and waterhead bearing the load.