Study on the Seepage in Natural Fracture Network of Rock Mass

Linear Cubic-Law for seepage is derived in single straight smooth fracture. For most natural fractures rock mass in engineering are coarse, so the seepage in them doesn´t abide by linear Cubic-Law, and the Cubic law for them need modify to use. The numerical simulation for fractures aperture was done according to statistical distribution regularity, and the fracture was divided into several length-equaling segments, the divided length-equaling inserted nodes in each fractures (DIN) can be defined, then the mean aperture for each segment was calculated, and the last part is the derivation of unit discharge formula and the water head formula for insert points by length-equaling division. Based on the seepage theory for network of rock mass, using unit discharge formula for coarse fractures, then the water head for each fracture node can be calculated, after then the following is unit discharge of fractures. The following conclusions can be drawn from this paper, that is there are great differences between the seepage for natural fractures network and smooth fractures network of rock mass: (1) the unit discharge formulas for coarse fractures and for smooth fractures are different; (2) the water head distributions form for them are different; (3) the calculation formulas for conductive matrix are different; (4) the ununiform aperture distribution was taking into consideration, which is more abide by the practical engineering. The study in this paper can give some references for practical engineering.