孔隙介质渗透力的细观数值解析

Numerical interpretation of seepage force in porous media based on micromechanics

为深入理解孔隙介质中的渗透力概念,分析了渗透力的力学本质,明确了渗透力的定义。从细观角度分析了渗流条件下土颗粒受力特点以及PFC3D对单一颗粒在渗流条件下的渗流作用力计算方法,建立了渗透力数值计算的细观颗粒流分析模型,利用PFC3D的流固耦合分析功能,研究了渗流条件下孔隙介质土体渗透力特性及数值大小。渗透力数值解与解析解对比分析结果表明:采用基于细观理论的PFC3D研究孔隙介质在渗流条件下的宏观受力特点是可行的;渗透力由所有土颗粒表面的法向应力和黏滞切向力合成。

In order to deeply understand the concept of seepage force in porous media, its mechanical essence is analyzed and its definition is exactly given. From the perspective of micromechanics, the mechanical characteristics of soil particle under percolation condition is analyzed, and the calculation method of singular particle＇s seepage force under percolation condition employed in particle flow code in three dimensions（ PFC3D） is discussed. Additionally, the analysis model of mesoscopic particle flow for calculating seepage force value is built. By using the fluid-solid coupling analysis function of PFC3D, the features and values of soil seepage force of porous media under percolation condition are studied. Through comparing the value of seepage force obtained by numerical method with that by analytical solution, the results indicate that it is feasible to study the macro-characteristics of driving force in porous media under percolation condition with PFC3D, which is based on mesoscopic theory. Moreover, the seepage force is a synthesis result of normal stress and shear viscous stress acting on the surface of soil particles.