Abstract: A coupling analysis model is proposed to study the hydro-mechanical response of the fluid flow in fractured rock mass with the method of discontinuous deformation analysis (DDA). A model of fractured rock mass is generated with the DDA method. Based on this model, the fracture water network is also generated with the matrix search method. In the fluid flow analysis, the cubic law is applied to study the steady flow along the fractures using the steady-state equilibrium iteration method. Hydraulic pressure is treated as a line loading in the DDA framework, and the aperture and hydraulic pressure in the fracture line are updated every iteration step, followed by the coupled motion equations expressed in the DDA framework, to study the interaction between the fluid flow along the fractures and the movement of the rock blocks. A real case of cavern excavation is selected to study the influence of fluid flow with water tunnel during the excavation and operation phases with the proposed DDA coupled 2D hydro-mechanical model. The results show that the DDA coupled hydro-mechanical model is suitable for the stability and seepage analysis of practical engineering problems.

Key words: fracture water network, coupled hydro-mechanical model, discontinuous deformation analysis (DDA), flow rate, underground petroleum storage caverns