Abstract：The approximate relationship between connectivity ratio and connectivity coefficient of fractures in rock mass is proposed. The equivalent permeability tensor of rock mass，which has single set of fractures，is deduced. The finite element method to analyze single-hole directional water pressure test is established，and a series of numerical tests are carried out. The numerical test results are used as train samples for BP neural network. The trained BP neural network combined with the information of single-hole directional water pressure test forms the methodology for the back analysis of the equivalent permeability tensor. The reliability of the method is verified by engineering example.
