Evaluation of the treatment effect of rear slope cutting on hydrodynamic pressure landslides: A case study

After the impoundment of the Three Gorges Reservoir, some huge ancient landslides were reactivated and deformed, showing typical hydrodynamic pressure landslide characteristics. The Baishuihe landslide was a typical hydrodynamic pressure landslide. The management department conducted slope cutting treatments from 2018 to 2019. To evaluate the treatment effect of rear slope cutting, this study analyzed the data of the surface deformation survey and field monitoring over the past 20 years and the characteristics of the reservoir water-triggered Baishuihe landslide deformation, and calculated the seepage field, displacement field, and stability coefficient before and after landslide treatment. The results showed that the deformation of the Baishuihe landslide was primarily related to a decrease in the reservoir water level. Owing to the poor permeability of the landslide soil, the decrease in the reservoir water level produced a seepage force pointing to the outside of the landslide body, leading to the step deformation of the landslide displacement. The landslide was treated by rear slope cutting, and the step deformation of the landslide disappeared after treatment. The hydrodynamic pressure caused by the change in reservoir water after cutting the slope did not disappear. However, as the slope cutting greatly reduced the overall sliding force of the landslide, its stability was greatly improved. Notably, high stability can still be ensured under extreme rainfall after treatment. Slope cutting is effective for treating hydrodynamic pressure landslides. This study can provide effective technical support for the treatment of reservoir landslides.

Automated summary

This study evaluated the treatment effect of rear slope cutting on the Baishuihe landslide by analyzing surface deformation survey data, field monitoring data, and calculating the seepage field, displacement field, and stability coefficient. The results showed that the decrease in reservoir water level caused deformation of the landslide, but the step deformation disappeared after treatment. Although the hydrodynamic pressure caused by the change in reservoir water did not disappear, the overall stability of the landslide greatly improved due to the reduction in sliding force. Slope cutting is an effective treatment for hydrodynamic pressure landslides, and this study provides technical support for the treatment of reservoir landslides.