Abstract: Due to various causes, it is often difficult in engineering practice to make a direct in-situ measurement of the elastic modulus EM of fractured rockmass. As an alternative method, the rock elastic modulus E measured in the lab is generally used to determine the elastic modulus EM of fractured rockmass. The strain coupled hydraulic model that is proposed in the paper has established the deformation coordination and stress balance relations between the fracture and the rock blocks in fractured rockmass. Considering the fact that water inflow in underground excavation in fractured rockmass can directly reflect the fracture connectivity and density, rockmass elastic modulus is calculated based on the said water inflow and the reduction factor of rockmass elastic modulus Rm, hereby providing a new possible way to determine the elastic modulus of fractured rock. The results of the model agree very well with the real data.

Key words: Elastic modulus of rockmass, Hydraulic conductivity, Fracture