多孔材料孔隙尺寸对渗透系数影响的数值模拟

采用有限元方法数值模拟了多孔材料的孔隙尺寸与等效渗透系数之间的非线性关系.有限元模型中的固体骨架和孔隙根据孔隙率的大小随机生成,模型中的材料参数和单元属性用ANSYS中的APDL参数化语言赋值.根据有限元随机模拟断面的流量分布和稳态渗流问题的达西定律,计算在不同孔隙尺寸的等效渗透系数,研究等效渗透系数与孔隙尺寸之间的关系.计算结果表明,在孔隙率不变的情况下,等效渗透系数与孔隙尺寸的平方成正比,该结论与经验公式相一致.而孔隙尺寸不变的条件下,随着孔隙率的增加等效渗透系数近似呈线性增加.

NUMERICAL SIMULATION OF RELATIONSHIP BETWEEN HYDRAULIC CONDUCTIVITY AND POROSITY SIZE FOR POROUS GEOTECHNICAL MATERIALS

The relationship between hydraulic conductivity of a porousmaterial and its number-size is simulated by using the finite element method.The solid matrix and the pore space are generated randomly according tothe materialporosity, and the material parameters and the element properties areassigned by theANSYS parameter design language. The equivalent hydraulic conductivity iscomputed according to the flow flux through some section computed by FEM andDarcy law, and the relationship between the equivalent hydraulicconductivity and the porosity number-size of porous materials is obtained.The numerical simulation shows that the equivalent hydraulicconductivity is directly proportional to the square of the porosity size whilethe porosity is constant, for which the proposed conclusion agrees well withempirical expressions. The equivalent hydraulic conductivity is directlyproportional to the porosity while the porosity size is constant.