Study of the Failure Mechanism and Progressive Failure Process of Intact Rock Patches of Rock Slope with Weak Surfaces

Abstract

Rock slope with weak surfaces is an important type of rock slope, whose stability is always governed by the intact rock patches. To better understand the failure mechanism and progressive failure process of the intact rock patches under real complex normal stress, a series of physical model tests as well as corresponding numerical modeling by numerical manifold methods have been conducted. Special attention has been given to the effects of the number, length and interval distance of the intact rock patches on the macro-observed failure process. Based on the test and numerical modeling results, the following conclusions are drawn: For the cases of the lower intact rock patches, which are located at the toe near the free surface, they are always the first to rupture, and their failure modes are mixed modes not pure shear modes. However, the failure modes of the upper intact rock patches are location dependent. The factors of the intact rock patches, such as the number, length and interval distance, affect the final failure surfaces of the lower intact rock patches, especially the groove locations that are induced by tensile rupture. In addition, the number factor mainly affects the value of the applied load that is needed to induce the failure of the slope. The length factor affects not only the applied load which is required to induce failure but also the time interval (load step gap) of the failure between the upper intact rock patches and the lower intact rock patches. The interval distance factor mainly affects the failure mechanism and failure mode of the upper intact rock patches induced by the applied load.