Stability Evaluation of Blocks Considering Block Surface Forces Induced by Rock Excavation

摘要

The stability issue of rock blocks is constantly encountered during the excavation of blocky rock masses. A stability evaluation method for rock blocks is proposed. This method firstly employs finite element method to calculate the surface forces of geological discontinuities. Then, a new block identification method is employed and blocks can be identified using FE meshes. Finally, by taking the calculated block surface forces into consideration, block safety factor can be obtained, thus reflecting the pressing and shearing effects of surrounding rock during excavation. An example is given and the effectiveness of the proposed method can be verified. It is discovered that when block surface forces are viewed as initiative forces of block, the stability results are completely different from traditional results, in which only block weight is considered as initiative force. As the real situation of blocks is considered, it is concluded that the proposed method is rational and provides a reliable method for evaluating block stability.