部分充填裂隙网络岩体的渗透特性分析

Permeability Characteristics of Fractured Rock Mass with Filling Medium

为研究充填裂隙网络岩体的渗透特性,结合Navier-Stokes方程和Brinkman-extended Darcy方程,构建了部分充填条件下的单裂隙渗透模型,推导了单裂隙渗流场分布特征,给出单裂隙渗流量的解析解,无充填的情况下该解析解可简化为立方定理表达式;后基于裂隙网络渗流原理,构建含充填介质裂隙岩体渗流网络的数学模型,并通过算例探讨了充填介质对裂隙岩体渗透特性的影响。算例结果表明:在相同裂隙宽度条件下,相比于立方定理,利用半充填裂隙岩体数学模型计算得到的渗流量减少约36.44%,充填介质对裂隙渗透特性具有显著影响;并且随着充填介质渗透率K减小、裂隙填充比β增大,裂隙渗流量逐渐减小。同时充填物的存在会导致充填裂隙的水力比降增加,进而渗流流速增大,局部发生冲刷侵蚀破坏的可能性提高,影响裂隙岩体的整体强度。

In order to study the permeability characteristics of fractured rock mass with filling medium,the seepage model of single fracture with filling medium is established and the analytical solution of seepage volume is given by combining Navier-Stokes equation and Brinkman-extended Darcy equation.Without filling medium,the seepage volume formula could be simplified to the cubic law.Based on the seepage principle of fracture network,the mathematical model of seepage network of fractured rock mass with medium is constructed,and the influence of the properties of filling medium on the permeability of fractured rock mass is discussed through an example.The results show that under the condition of semi-filling and the same fracture width,compared with the cubic law,the seepage volume of the fractured rock mass considering the filling medium decreases by about 36.36%,indicating that the influence of filling medium on fracture permeability must not be ignored.The smaller the permeability coefficient K and the higher the filling ratio(β)is,the lower the seepage volume is.In the middle of the seepage domain,the gradient of water considering the filling medium is larger,which may lead to local erosion and damage and affect the strength of the rock mass.