Deformation characteristics and instability mechanism of large-scale anti-dip rock slides

Abstract

The anti-dip bedding rock slopes have threatened global infrastructure construction and urban expansion seriously. Taking the Guang'an Village rockslide as an example, this paper firstly studied the deformation characteristics of the rockslide with anti-dip bedding structure based on in-situ investigation and monitoring, and then the relevant influencing factors were summarized. On this basis, a new evolution model of continuous-pushing-section pressing locked-section and the instability mechanism of the rock slope were proposed. Finally, the applicability of the model and the deformation tendency of the rock slope were further discussed. A catastrophic sliding event has once occurred in the Guang'an Village rockslide in 2017, after which the deformation of the potential source area III (PSA-III) was accelerating. The presence of the sliding-prone geological structure provides the basic conditions for the deformation of the rock slope and the development of the sliding zone. Rainfall is the major external trigger that promotes the deformation. As the sliding zone extends forward, the overlying deformation body will keep on pushing against the preceding rock mass, which will contribute to the forward extension of the sliding zone as well. When the final locked section is crushed, the rock slope will lose balance. According to the observation in the field, the PSA-III is in the late stage of the deformation-increasing phase currently. This study can provide a reference for the analysis of failure mechanism and the design of monitoring and mitigation of other large anti-dip bedding rock slides.