Emergency treatment effect evaluation of rear-slope cutting and front-slope pressing on a hydrodynamic pressure landslide: a case study of the Shuping landslide in the Three Gorges Reservoir Area

Hydrodynamic pressure caused by a decline in reservoir water-level is one of the dominant factors inducing the deformation of reservoir landslides in mountainous areas, which can lead to the revival of some hydrodynamic pressure landslides. Rear-slope cutting and front-slope pressing are the most common emergency treatment methods for hydrodynamic pressure landslides. To evaluate the effects of emergency treatment and predict the development trend of landslide deformation, we selected the Shuping landslide, which is a typical hydrodynamic pressure landslide in the Three Gorges Reservoir. Based on the surface deformation surveys and field monitoring data collected over the past 20 years, the deformation characteristics before and after the emergency treatment of the Shuping landslide were analyzed, and changes in the seepage field, displacement field, and stability coefficient before and after the landslide emergency treatment were simulated. The results revealed that a decrease in the reservoir water-level was the primary factor governing the deformation of the Shuping landslide. The implementation of front-slope pressing magnified the hydrodynamic pressure effect but increased the anti-sliding force. Simultaneously, slope cutting significantly reduced the sliding force of the landslide. Therefore, the landslide improved from an unstable state to a quasi-stable state. However, the continuous development of the landslide front bank collapse and heavy rainfall will reduce the stability of the landslide. Therefore, it is necessary to conduct long-term monitoring and design follow-up prevention and control projects.