Study of the effect of pre-existing crack and water saturation on strength of rock-like

In civil and mining engineering works, the strength and rigidity of the rock mass can be affected by the existence of many kinds of discontinuities related to shear zones, faults, and bedding planes. This paper focuses on analyzing the effect of a single pre-existing crack on the strength and deformation behavior of rock samples based on the experimental results and to elucidate the influence of water on crack development. The triaxial compression tests were carried out on a variety of the rock samples constituted of a pre-existing crack with plane surface and rough surface with a variety of slope 30°, 45°, and 60° in the dry state and saturated state. Test data show that the existence of cracks promotes the lessening in the overall strength of the rock; though, the extent of the decrease of strength is associated with the rock properties. The lowest strength was detected for the samples with the greatest slope value. The influence of the fracture angle on the strength is independent of the drying and saturated environment of the rock mass. The strength and compressive behavior of the mass of fractured rock with different slopes under saturated conditions is lower than under drying conditions.