Water Flow through Random Crack Network in Saturated Soil

The presence of cracks can significantly decrease the stability of slopes. Yet the capability of predicting the effect of cracks on slope performance is still limited. This paper studies the hydraulic properties of random cracks in soil. First, the statistical parameters for the geometry of cracks in soil are reviewed. Next, a method of generating a random crack network based on the statistical parameters is presented. Then water flow through the generated random crack network is studied through a numerical model. Finally the hydraulic properties of the random crack network are investigated. Results show that a random crack network consisting of two orthogonal sets of cracks behaves like an isotropic porous medium as expected when the two sets of cracks have similar mean length, mean aperture and density. If the relative orientation is not orthogonal, then the permeability of the random crack network will be anisotropic. The anisotropic ratio increases as the relative orientation decreases. The directional permeability increases with the mean crack aperture and length as expected. On the other hand, the changes in aperture do not affect the shape of permeability ellipses and the equivalent porous medium assumption.