Abstract: The block theory, which was first proposed by Shi Genhau, a Chinese scholar, is mainly used for analyzing the geometric shape and movement possibility of blocks in 3D space. Its key is to eliminate unlimited blocks and movable blocks, find out and study the key block at free face, and propose rational reinforcement measures for potential instable blocks. There are many factors influencing the stability of key blocks when this theory is used in analyzing the stability of rocky slope. In this paper, the influence of unloading due to the excavation of the rocky slope is considered by using uniform test design method, and the effect of five factors such as cohesion, friction angle and seismic peak acceleration on the stability of key blocks of rocky slope is studied and evaluated, providing some references to practical engineering construction.

Key words: Block theory, Key block, Unloading, Uniform test design method