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Abstract Joints are the main passages for underground water flowing through rock-masses. Fluid flow through joint has been one of research focuses on joint hydraulic properties. Due to the joint surface is rough and uneven，flow through a rough joint is greatly different from that between a pair of parallel plates. A void model for fluid flow through a rough rock joint is established. The joint plane is divided into a series of square meshes with the dimension of 1 mm×1 mm，the apertures of the grids of each mesh are determined by the 3D void composite topography. Assumed that the cubic law is applicable for fluid flow analysis in each mesh，analyse are performed one mesh by one mesh. Fluid flow through the whole joint plane is calculated by considering the continuity equation among the meshes and a procedure for flow calculation was compiled by MATLAB functions. Then an artificial marble tensile fracture is taken as an object，different contact states are formed by offsetting the upper joint surface along the length direction from the lower one for 1，2，3，4，5 and 6 mm respectively. The 3D void composite topographies in these six cases are calculated by contact algorithm，thus obtaining joint aperture distributions and the mean apertures under different contact states. The theoretical volumetric flow rates under different contact states calculated by void model and cubic law are compared with the results of laboratory flow tests carried out on the marble joint specimen. It indicated from the comparison that the results of void model are closer to experimental results than that resulting from cubic law and there existed a difference between void model and experimental results. And the reasons resulting in the difference were discussed.
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Received: 27 November 2010
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2011, Vol. 30 
