Analysis of basic characteristics and formation mechanism for the collapse in back of the Panda Garden rearing sheds located in Wolong Town

5.12 Wenchuan earthquake triggered a large number of collapses, landslides and other secondary disasters caused serious loss of life and property. At the same time, the earthquake generated a lot of loose debris and serious injured and damaged the mountain so as to form potentially dangerous rock which serious threat to people´s safety in the future. On the basis of detailed investigation of the mountain collapse in back of Panda Garden rearing sheds, the collapse failure mechanism and the instability modes of potential dangerous rock are revealed by the analysis of topography, lithology and rock structure. Discrete element software is used to simulate the failure process of collapse in the earthquake. The results showed that the passive protection facilities within a certain range in the slope toe have obvious block and restriction for falling stone. This provides the basis for supporting design, and the evidence for the collapse formation mechanism study under strong earthquake.