Base Friction Modeling of Toppling Failures in Jointed Rock Slopes

摘要

This paper reports results from a study of sliding and toppling failures in jointed rock slopes using the base friction modeling technique. The base friction modeling technique is a commonly used physical modeling technique in rock mechanics to study behavior of rock masses. In a base friction model test, a two-dimensional model is prepared and laid horizontally on the belt of the base friction machine. The model, is then dragged by the belt against a fixed barrier. The frictional drag between the base of model and the belt simulates gravity in the direction of the belt movement. Results from base friction model tests on model rock slopes consisting of rectangular wooden blocks show that the factors affecting model behavior are 1) the geometry of the block system that comprises the rock slope, and 2) the friction angle of the block-to-block contact surfaces. Base friction results are compared with analytical results, and there is good agreement between our experimental results and analytical results. All the experimental results show that as the friction angle increases the initial behavior changes from sliding to toppling and sliding and then to toppling. A special case of a "cross-jointed" rock mass with an amount of "offset," was also studied. Base friction model test results show that as the amount of offset increases, the initial behavior of the slope changes from toppling to toppling and sliding and then to sliding.