Deformation and control engineering related to huge landslide on left bank of Xiluodu reservoir, south-west China

Abstract

This paper reports a comprehensive investigation on the deformation characteristics, failure mechanism and stabilisation treatment of Baitieba slope on the left abutment of Xiluodu hydropower plant on the downstream reach of Jinsha River. In the first two years following the excavation, the development of the slope movement after rainfall became a threat to the water inlet and spillway tunnels constructed beneath it, as well as to the construction of the plant. On the basis of field investigation and real-time monitoring, the deformation characteristics and the failure mechanisms of the slope were investigated. There are two sliding surfaces in the slope: a shallow one which is a rotational slide; a deep one as a result of the reactivation of the ancient slip zone induced by excavation which is a translational slide. The deep sliding surface is dominant in translating the global soil mass to move. Based on the analysis of the movement tendency and stabilities, the efficacies of the used stabilisation measures, including reinforcements, piles, concrete protections, drainages and infiltration protection are assesses. It has been found that the used treatments effectively retarded the deformation of the slope to a very slow creep rate of .33–.64 mm/month in the last two year. The slope is gradually stabilised.