Modelling of hydro-mechanical coupling and transport in densely fractured rock mass

Abstract

A numerical model is presented to study hydro-mechanical coupling process based on the rigid body spring method and the discrete fracture network model. In order to realistically simulate the constitutive behaviours of fractures, a non-linear constitutive model is employed, in which non-linear normal stress deformation relationship, tangential slipping failure and dilation effects are considered. To investigate coupling effects on transport, a particle tracking procedure is also incorporated to account for solute movement. Stress effects on flow field and transport are studied on a typical fracture network provided by the DECOVALEX project. Results show that it is the non-linear normal deformation that mainly influences flow and transport when the confining stress is relatively low and the stress difference is not large. When the stress increases and stress difference becomes larger, dilation effect gradually becomes the governing mechanism. These results are compared with other researcher’s work and reasonable agreements are obtained.