Triggering mechanism and deformation characteristics of a reactivated ancient landslide, Sichuan Province, China

Abstract

An understanding of the triggering mechanism and deformation of reservoir landslides is useful for evaluating stability and developing corresponding treatments. This study uses the Guazi landslide, a reactivated ancient landslide, as a research object. The triggering mechanism, deformation characteristics, and evolution process of the landslide are discussed based on detailed site investigations, drill holes, and various monitoring data. The results show that the reactivated zone was mainly concentrated in the lower part of the landslide area and that some surface displacements occurred in other parts, while the deeper deposits remained stable. The whole landslide underwent slow creep deformation. The Guazi landslide is a multistage topple failure landslide, and sudden increase in the reservoir level softened the lower part of the landslide; thus, significant deformation and surficial collapse occurred. At present, the reactivated landslide is stable overall; however, confirming its stability in the future is difficult.