非饱和土力学的分形理论

室内试验确定非饱和土的力学性质有许多困难,特别是非饱和土的渗透系数,非饱和土渗透系数量级小,随吸力变化幅度大。非饱和土的孔隙结构与非饱和土的力学特性有关,非饱和土的孔隙结构用分形模型表示,分形理论可以用于研究非饱和土的力学特性。本文采用分形理论描述土体孔隙特性,导出非饱和土的水份特征曲线、渗透系数、剪切强度、膨胀变形和压缩变形的表达式。非饱和土的吸力与孔隙的关系由Young-Lapalace方程表示,将孔隙与非饱和土力学性质联系起来。文中非饱和土的理论公式与试验结果符合得很好。

Fractal Theory of Unsaturated Soil Mechanics

There are many difficulties for laboratory test to determine the unsaturated soil mechanical properties, especially the permeability coefficient of unsaturated soil, due to that its scale is small and the permeability coefficient of unsaturated soil changes greatly with suction. The pore structure of unsaturated soil is related to its mechanical characteristics, and the pore structure of unsaturated soil can be expressed by fractal model, the fractal theory can be used to study the mechanical characteristics of unsaturated soil. This paper uses the fractal theory to describe the pore characteristics of unsaturated soil and the expressions for water characteristic curve, coefficient of permeability, shear strength, expansion deformation and compression deformation of unsaturated soil are derived. The relationship between suction of unsaturated soil and its pore is expressed by Young Lapalace equation, which connects the pore of unsaturated soil with its mechanical properties. In this paper, a theoretical formula of unsaturated soil was found to be in good agreement with the test results.