Coupled shear-flow tests for rock fractures with visualization of the fluid flow and their numerical simulations

A series of laboratory coupled shear-flow tests for fracture replicas under normal stresses was performed with visualization of fluid flow using a newly developed coupled shear-flow-tracer testing equipment and these laboratory tests were simulated by using FEM, considering evolutions of aperture and transmissivity with large shear displacements. The distributions of fracture aperture and its evolution during shearing and the flow rate were calculated from the initial aperture and shear dilations and compared with results measured in the laboratory coupled shear-flow-tracer tests using transparent fracture replicas and a CCD camera that provides continuous images of contact area and flow path evolution in real-time of the shearing tests. Numerical simulation results such as aperture and contact distributions agree well with the images obtained from the coupled shear-flow tests of fracture specimens with visualization of the fluid flow. The numerical models captured complex behavior of fluid flow in fracture samples and agree well with the experimental flow rate results.