三维应力作用下岩体单个裂隙的渗流特性分析

Analysis of seepage characteristics of rock masses with a single joint under 3D stresses

天然岩体中存在着大量的孔隙和裂隙,这些缺陷不仅改变了岩体的力学性质,也严重影响了岩体的渗流特性。在对现有裂隙岩体渗流特性研究成果进行分析的基础上,讨论了岩体单个裂隙的力学性质和渗流对单个裂隙岩体产生的力学作用,研究了岩体单裂隙渗透系数与岩体三维应力的关系,考虑了裂隙粗糙度对渗流的影响以及不同方向应力对渗透性影响的差异,分析了单个裂隙岩体在三向应力作用下的渗流特征,得出了裂隙所受三维应力与渗透系数关系式,认为垂直于裂隙面的应力对岩体渗透性起主导作用,岩体渗透系数随垂直裂隙面应力的增加而迅速减小。通过与渗流规律试验结果对比分析,证明了所得单个裂隙岩体渗透系数表达式的正确性。

There are large numbers of holes and cracks existed in the natural rock mass,these defects not only change the mechanical character of rock mass,but also affect the seepage characteristics of rock mass.Based on analyzing the present production of seepage characteristics of fractured rock mass,the mechanical character of a rock mass with a single joint and the mechanical function that the seepage impacted on rock mass with a single joint are discussed;and the relation between the permeability coefficient and 3D stresses in the rock mass with a single joint is studied.The influence of the crack coarseness degree on the seepage and the different influences of the different acting directions of stresses on the seepage characteristics of rock mass are considered;the seepage characteristics of rock masses with a single joint under 3D stresses is analyzed;and the relation between stresses acted on the crack and the permeability coefficient is proposed.It is shown that the vertical stress acted on the face of the crack takes a dominant effect on the permeability of rock mass;and the permeability coefficient decreases rapidly with the increasing of the vertical stress acted on the face of the crack.By analyzing and comparing the result of an experiment of seepage law made by Zhao Yang-sheng,the correctness of the expression of permeability coefficient of fractured rock mass with a single joint proposed in this paper,is proved.