Abstract:The composite element method for the seepage problem in the rock masses containing complicated fracture network is studied. Firstly,the Monte Carlo method is adopted to generate the stochastic fracture network according to the given probability distribution features;and then the fracture network is located within the conventional finite element to form composite element,which is composed of several subelements incised by the fracture segments. Based on the deduced algorithm,the nodal hydraulic potential of respective subelements can be calculated;and then the analysis of the seepage characteristic in rock masses is performed. The main features of this method are as follows:(1) it can be integrated into conventional finite element method;(2) the number,position,orientation,trace and aperture of every fracture are taken into consideration in the analysis;(3) the permeability of rock and the flow exchange between rock and fractures are considered;(4) the obturated fractures are not omitted and their effects on the seepage are taken into account;and (5) the topological information of composite elements is obtained by the intersection and incision between the fractures and the finite element boundaries and those among the fractures themselves. In this way,the composite element mesh generation of rock masses is not restricted by fractures and can be considerably simplified. The composite element method provides a new approach of the numerical simulation for the seepage solution in the rock masses containing complicated fracture network. The feasibility and effectiveness of this method are verified by the numerical example.