ABSTRACT
To examine the mechanism of the change in permeability around a tunnel due to excavation, two in-situ tests are simulated by the coupled mechanical and hydraulic model with a non-linear elastic constitutive law for single fracture and anisotropic properties equivalent to the fractured rock mass. Through the comparison between measured and calculated results, the mechanism is estimated. It is concluded from the examination that the behavior of the horizontal fractures has a large effect on the reduction of the hydraulic conductivity, and the deformation in the drift direction also has an effect on the change in the hydraulic conductivity. Moreover, it is found that the fractures contributing to the mechanical behavior may be limited.
