Experimental investigation on deformation and failure mechanism of waste dump with partial-weak basement

Abstract

A non-uniform basement condition usually causes dump disasters. Two sets of base friction tests were carried out to discuss the deformation mechanism of the waste dump with partial-weak and total-hard basement. By the image speckle analysis and point-tracking technology, dump displacements and strains were obtained, and the deformation mechanism, stability, failure process of the waste dump were analysed. We could concluded that: (1) a waste dump with total-hard basement has higher stability than that with partial-weak basement. (2) The dump displacement exhibits a distribution of five flat regions that are connected by four steep increasing regions. (3) The dump deformation could be categorized into three phases: continuous deformation phase, crack-failure phase and final stability phase. In crack-failure phase, the deformation process of a total-hard basement waste dump presents a traction-crack-slide feature, but that of a partial-weak basement waste dump exhibits a subsidence-crack-rotation pattern. (4) In the deformation process, a total-hard basement waste dump is mainly affected by tensile stress, and its crack type is classified as tensile crack. While a partial-weak basement waste dump is subject to the coupling action of tensile and shear stress, and its crack type is shear crack. Both total-hard and partial-weak basement waste dumps show volume expansion. (5) With regard to the deformation control project of partial-weak basement waste dumps, strengthening the weak basement and increasing the anti-sliding force of the dump slope are recommended to reduce the vertical and horizontal deformation. These results have guiding significance for the deformation mechanism, stability evaluation and reinforcement measures of partial-weak basement waste dumps.