Karstification and slope failure in carbonate areas of Three Gorges Reservoir

A large number of karst unstable banks in the gorge area of the Three Gorges Reservoir stand on both sides of the main stream of the Yangtze River， endangering the safety of the golden waterway. Based on field survey， exploration and mechanical analysis， this work analyzes the relationship between karstification and slope failure in the carbonate areas of the Three Gorges Reservoir. The field survey shows that there are many unstable slope phenomena related to karst caves， dissolution fissures， dissolution zones， dissolution troughs， dissolution ditches and other surface karstification on the carbonate bank slope. There are 186 karst potential geo-hazards in Wu Gorge， including 37 potential landslides and 6 large-scale dangerous rock masses. The mechanical analysis of rock mass indicates that the joints / cracks will gradually expand due to the decrease of effective stress and strength under heavy rainfall， impounding and rock mass degradation. At the same time， the crack growth rate of rock mass deterioration in the water level fluctuation zone is about 1，300 times higher than the average dissolution rate in the Three Gorges， which greatly accelerates the evolution process of unstable rock mass which has entered the yield state. Dissolution is the most basic action of karst bank slopes， and the long-term fluctuation of reservoir water accelerates the evolution of karst bank slopes. This study provides technical support for the identification and disaster prevention and mitigation of unstable banks in the gorge section of the Three Gorges Reservoir area.