Numerical Simulation Of Three-dimensional Fracture Network Seepage In Soil

Fracture network existing in the soil affects the movement of water in the soil,thereby affects the soil permeability and strength characteristics. Typically, the testmethod can be used to study the characteristics of the fracture network seepage, butin the experimental study of indoor or outdoor, soil is vulnerable to be disturbance.Soil sample size will be limited due to the actual conditions in the experimentalstudy. Therefore, this paper adopted the method of numerical simulation to study theseepage of fracture network.In this paper, the following assumptions are proposed for the properties of thefracture network. Two surfaces of the single fracture are impermeable plane, andparallel to each other. The width of the two surfaces is a fixed value in the range offracture. There is no filler between the two surfaces of every fracture. Water canflow freely in the fracture and ignore the water's flowing in a directionperpendicular to the fracture plane. Since the above assumptions, the fracture can beconsidered as an isotropic substance in the direction of along the fracture surface.The head of the intersecting line of two fractures is a fixed value because energyloss of the water crossing intersecting lines of the fracture network is not consideredin this paper.In this paper, the assumptions of single fracture are analyzed exhaustive.Establish the boundary integral equation of the single fracture using the principle ofthe boundary element method. The integral equation is based on the control equationand boundary condition of the single fracture seepage. Endure the boundarycondition to each node of the single fracture. Solve the matrix equation aftercalculating the elements of the coefficient matrix of the matrix equation. The headvalue and the flow value of every node can be find from the result of the matrixequation. Calculate the seepage of two intersecting fractures considering twoassumptions: the unique head value and the balance of the flow of the crossing lineof two fractures. Get the head value and the flow value of every node of twofractures and the crossing line.This article complied the three-dimensional fracture network seepagecalculation program based on the principle of boundary element method incalculating seepage of fracture network and the analysis of single fracture's seepageand intersect fracture's seepage. The program contain several parts: discretion of thefracture network, calculating of the coefficient matrix, setting boundary conditionsof every node and solving the matrix equation. Every part of the program is narrative in this paper. At the end of third act, a simple example is shown to proofthe correctness of the program.In the fourth act of this paper, calculate several fracture networks with differentshape using the program complied in the third act. Make a proper analysis of theresults after obtaining the flow values of rectangle fracture network, triangle fracturenetwork, keystone fracture network and mix shape fracture network.