A new apparatus for investigating stress, deformation and seepage coupling properties of rock fractures

A true triaxial apparatus which is composed of three units was presented. The apparatus allows for investigations on deformation and seepage behaviors of a single rock fracture subjected to lateral stress and normal stress. The first unit has three jacks which can apply loads independently in three orthogonal directions. The second unit is used to supply water inflow, control seepage pressure and measure flow velocity in real time. The third unit is for measuring the normal deformation of rock fractures. Some tests for investigating the normal deformation and seepage behaviors of rock fractures subjected to normal and lateral loads on hard granite specimens with an artificial persistent fracture, were introduced. The results show that both the normal deformation and the hydraulic conductivity are influenced not only by the normal stress but also by the lateral stress. It is also shown that the aperture and the hydraulic conductivity decrease with the increasing normal stress but increase with the increasing lateral stress and both the aperture and the hydraulic conductivity obey exponential relationships with the normal stress and the lateral stress.