Hydromechanical modelling of a tunnel excavated in argillaceous rock

The paper presents selected results from a hydromechanical analysis of an excavation at great depth in argillaceous rock. A constitutive model specifically developed for this type of materials has been used. It incorporates anisotropy of strength and stiffness, stress-strain nonlinearity, significant softening after peak, tirne-dependent creep deformations and permeability increase due to damage. Adopting this model, the patterns of pore water pressures and ground displacements observed during the excavation are generally satisfactorily reproduced. The results illustrate the signifi cance of rock anisotropy and creep as well as of the development of a damaged zone around the excavation