Slope Stability Analysis and Remediation Measures in the Three Gorges Reservoir Area: A Case Study of a Soil–Rock Mixed Slope in Zhongxian County

Abstract

This study investigates a soil–rock mixed slope in the Dongxi Community resettlement area of Zhongxian County, Three Gorges Reservoir region, based on field investigation and the strength reduction method (SRM) to evaluate its natural stability and verify the effectiveness of anti-slide piles reinforcement. The slope is 16–18 m high, with upper fill and silty clay overlying sandstone and mudstone. The fill roadbed at the crest has undergone a collapse zone of approximately 20 m×3 m, accompanied by cracking and retaining wall damage. Under natural conditions, the factor of safety (Fs) is 1.06 and the maximum displacement is 4.82 cm, indicating a basically stable state with insufficient reserve, while plastic deformation concentrates near the steep crest section. After installing 14 rock-socketed anti-slide piles (20 m in length, 5 m spacing, 8 m embedment into bedrock), Fs increases to 1.42 and displacement drops to 0.006 cm, representing a 34.0% improvement and a 99.9% reduction, respectively; both the localized deformation and plastic zone expansion are significantly restrained. The results demonstrate that anti-slide piles can effectively enhance the load-transfer mechanism of such soil–rock slopes.For long‑term performance under reservoir operations and rainfall, complementary drainage systems and dynamic deformation monitoring are recommended.This study is conducted only on a single engineering site, so its results are mainly applicable to slopes with similar geological, geometric and hydrological conditions. It should be noted that the coupled effects of rainfall infiltration and reservoir water‑level fluctuation were not explicitly simulated in the numerical analysis, as this study focused on the dry natural condition; this limitation should be addressed in future work.