The Research Of Fracture Network In Rock Of Wu Dong De Hydropower Station Of Dam

During the long Geological process, by Tectonic movement, Unloading, Weathering and so on, Internal and surface of rock has accumulated various types of uncontinuous structural planes, such as joints, faults, ground surface dislocation, weathered fractured and so on. Fracture is weak structural plane of rock mass, and it is the passage of fluid flow and solute transportation. It controls the morph, strength, permeability of rock to make the continuous and integrity of rock is destroyed, and makes the rock heterogeneous and anisotropic. Describing the fracture network accurately is the base to obtain reliable rock mass mechanics models and seepage models.The paper has investigated the distribution of fracture in Wu Dong De hydropower station of dam and to statistics fracture in the suitable area of catalog face. Firstly, grouping the measured fractures to obtain the occurrence and distribution patterns of each set fracture. Secondly, analyzing the trace length of every set fracture to obtain the mean, variance and specific probability distribution function of trace length. Thirdly, generating random fracture network model with Monte-Carlo and sampling in the generated random fracture network to test, comparing the trace length , occurrence and amounts in check face and catalog face, using inverse method to modifying the mean of fracture diameter, standard deviation and fracture density correction factor to get a good fitting result. At last, using the established fracture network model to obtain the location, direction, fracture diameter, three dimensional density.This paper has established the fracture network model of Tunnel 46 and Tunnel 59, comparing the check face and catalog face of two tunnels to see the measured fracture is the same as the simulation fracture in occurrence, the mean and standard deviation of trace length and amount. It fits very well. The established fracture network meets the reality. Main conclusions are showed as follows:(1) The measured fractures of Tunnel 46 and Tunnel 59 are grouped into two sets and obey the Fisher distribution. The mid angle fracture has the largest proportion, and the dip-direction of one set fracture of two tunnels is about 270°. (2) The mean and standard deviation are 1.6m and 0.6.They obey the Fisher distribution. (3) The mean and standard deviation of the measured fracture in two tunnels are about 1.6m and 0.9; The mean of the fracture diameter is 3-6m, standard deviation is about 0.8; three dimensional density of every set is 0.01-0.09 piece/m~3.