Based on Betti energy reciprocal theorem

initial flexibility tensor and damage evolution of rock mass subjected to seepage pressure are presented. And an elastic fracture-damage constitutive equation taking account of seepage pressure is also established. The concept of additional flexibility tensor is introduced to indicate the influence of seepage pressure on the mechanic characteristics of rock mass. The results obtained from a practical project show that the seepage pressure is of great importance to damage evolution when there is groundwater flow in fractured rock mass.