Experimental Study on the Effect of Water on Shear Strength Characteristic of Shale

In order to understand the shear strength characteristic of water-sensitive shale under the effect of water in the northwest of Hubei province, we carried out direct shear tests of shale in natural and water-saturated states along its bedding plane with original shale samples taken from the Guzhu expressway and analyzed the shear stress-displacement relationship under different normal stresses and explored the influence of water on shale shear deformation and strength characteristic. This study shows that the shear stress-displacement curve of shale in natural state and water-saturated state presents significant similarities and differences; compared with natural shale, water-saturated shale witnesses an obvious drop in its cohesive force, internal friction angle and residual angle of internal friction; shale in natural state presents apparent brittle failure characteristic while water-saturated shale to some extent exhibits ductile failure characteristic.