考虑三维形貌特征的粗糙节理渗流空腔模型研究

 为研究粗糙节理中的渗流，建立节理渗流空腔模型。将节理平面离散成1 mm×1 mm的单元格，单元格节点处的隙宽值由节理三维空腔组合形貌确定，假设单元格内渗流服从立方定理，逐一对单元格进行分析，用连续性方程求解整个节理面渗流，编制MATLAB程序进行计算。用大理岩人工节理试件沿节理长度方向将同一节理上表面相对下表面分别错开1，2，3，4，5和6 mm，形成节理不同的接触状态，计算这6种情况下的节理三维空腔组合形貌，得到不同接触状态下节理的隙宽分布和平均隙宽值。将节理渗流空腔模型和立方定理在不同接触状态下的渗流计算结果与节理试件在不同接触状态下的室内试验结果进行比较。分析结果表明：节理渗流空腔模型计算结果比立方定理更接近室内渗流试验结果，但是空腔模型计算结果和试验结果还有一定的差距，并对其误差存在的原因进行分析。

STUDY OF VOID MODEL FOR FLUID FLOW THROUGH ROUGH JOINT BY CONSIDERING 3D TOPOGRAPHY CHARACTERISTICS

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.