Laboratory Study on Fluid-Induced Fracture Slip and Permeability Evolution in Marble Fractures

The increased fluid pressure in faults/fractures can trigger the decrease of shear strength and induce the faults/fractures to become instable. A series of novel fluid-induced fracture slip experiments are conducted in laboratory on the prefabricated flat fracture under various normal pressures. Our experimental results show that the effective normal stress and shear strength of fractures decrease as the fluid pressure increases. However, for the fracture with high normal stress or smooth surface, the relationship between fluid pressure and effective stress is not suitable for the conventional effective stress principle. With the increase of fluid pressure, the fractures in the critical stress state experience three slip intervals, namely, quasi-static slip (slip velocity