A numerical study of water percolation through an unsaturated variable aperture fracture under coupled thermomechanical effects

In calculation of ground water travel times associated with performance assessment of a nuclear waste repository, the role of fractures may turn out to be very important. There are two aspects related to fracture flow that have not been fully resolved. The first is the effect of coupled thermomechanical impact on fracture apertures due to the thermal output of the nuclear waste repository. The second is the effect of the variable aperture nature of the fractures. This paper is an exploratory study of the impact of these two effects on water percolation through unsaturated fractures. The paper is divided into two main sections. The first section describes a calculation of the thermomechanical behavior of the geologic formation around a waste repository