Especially for open pit mining, one can not always develop every ore deposit distributed on the surface and so, one usually tries to excavate down to greater depth in order to get larger volume of the material from the deposit which is already begun to develop. Since slope stability decreases with increase of height of the rock slope, it is important to know how to excavate in order to stabilize the rock slope and how deep one can mine down.
As the properties of the rocks of which the slope consists can not completely be determined from observation of a section of the slope because those are greatly different if the positions are different. It suggests that prediction of stabilility of rock slope is difficult in comparison with case of soil slope.
However, recent rapid progress in higher performance and larger capacity of computer enables to deal with the problems which are complicated to some degree, that is, it is possible to do approximate prediction for a problem through numerical simulation by putting some assumed conditions into calculation and it is mostly effective measure.
The authors carried out three dimensional elastic analysis by the boundary element system developed by them, in which soft layer is modeled as the joint elements, making an existent limestone quarry an object of study. They carried out numerical simulation of behavior of rock slope and showed the predicted results on the stability of the slope currently remained and on the stability decreases for the cases that rock slope becomes higher with progress of mining in future.
