Research on Unstable Rock Stability Evaluation and Rockfall Motion Characteristics of Chenjiashanping

Unstable rock relicts in Chenjiashanping are part of the major geodisasters which were contributed by the effect of the 2008 (8.0 MS) Wenchuan earthquake in Chenjiashanping with epicenter, 80 km west-northwest of Chengdu, Wenchuan County in Sichuan Province of China. Xiangzhang slope hosts lots of displaced unstable blocks of rocks tilting in different directions with sizes ranging from few centimetres to tens of meters. These unstable rocks are composed of highly weathered sandstone and alluvial gravelly soils, which have been cut by multiple sets and co-sets of irregular fractures and joints. Once these unstable rocks topple or slide, they will cause severe effect on the lives and properties of the local people living just below the Xiangzhang slope in Shimen Village. In view of this, this paper analyzed the probable failure mechanism, speed, motion characteristics of these unstable rocks, and proposed some geotechnical engineering remediation works which would contribute in geodisaster mitigation and prevention.