Comprehensive assessment and global stabilisation measures of a large landslide in hydropower engineering
Résumé
From 20 October to 5 November 2008, Gu-shui hydropower station of south-west China experienced a continuous intense rainfall. A landslide was reactivated on the Zheng-gang deposit body in the dam site area. Based on the comprehensive geological field investigations, the evolution process, formation mechanism, deformation mechanism and instability mode of the slide were analysed. The landslide is mainly composed of bedrock, slips zone soil and unconsolidated accumulation, and the slip zone soil is the transfixion slipping surface. The subsequent rainfalls increased the tension crack connectivity and the tensile strength gradually decreased. Then, the landslide is in a limit state and exhibit creep deformation. Prompt remedial works are needed due to the possibility of triggers and several stabilisation measures are evaluated. After comparison and optimisation, the most appropriate global remedial measure was proposed. Drainage measures are also considered and the landslide will be safer.