Abstract:

Huge hazards are frequently caused by earthquake-induced rock avalanche. The study of dynamic response characteristics and failure mechanism of the rock slope in specific geological condition is a challenging issue in geotechnical engineering. In this paper, a shaking table test that reproduces the Shuiqiuchi rock avalanche was carried out to understand the dynamic response and failure mechanism of rock slope controlled by faults. The testing results show that when the dip angle of the fault is greater than a specific critical angle, part of the reflected and transmitted waves at the discontinuous interface change into sliding waves, resulting in a sudden change in the acceleration response at the fault. The peak acceleration amplification factor inside the model slope presents a significant three-stage trend. Peak horizontal acceleration amplification factor increases obviously with elevation, while peak vertical acceleration amplification factor increases slightly with elevation. The natural frequency curve of the slope model can be divided into three stages with a downward trend, which indicates that the dynamic characteristics of the model have changed. By comparing the shaking table test with the Shuiqiuchi rock avalanche prototype, the main failure mode of the rock slope with fault structure is found as follows: the slope crest first shows vertical tensile cracks under the seismic load, followed by cracking damage of the fragmented rock mass in the hanging wall of the fault, and finally sliding occurs along the fault surface. This research could provide references for the early-warning of granite avalanche, and offer the basic data and scientific support for the development of Qinling Mountain geological heritages.

Key words: Shuiqiuchi rock avalanche, fault, shaking table test, seismic response, dynamic failure characteristics