Failure mechanism and controlling measures of cut slope instability at Shouling temple, Luhuo County, Sichuan Province

The Shouling temple in Luhuo County, Sichuan faces an urgent situation due to the construction of the Future Hall. A five-level excavation slope with a height of 21.8 m and a slope angle of 55° to 75° was formed on the northwest side of the site, leading to local damage at the toe of the slope. Field investigation and numerical simulation analysis indicate that the slope formed a circular sliding surface within the silty clay layer, with stress concentration at the toe of the slope. Under rainfall conditions, the bulk density of the soil increases, while the cohesion and internal friction angle decrease sharply. The maximum horizontal displacement can reach 3.4 m, resulting in a pushing-type landslide and slope instability. The study area is located in a high-intensity seismic zone. The vibration loads generated by earthquakes and large-scale machinery operations will have serious adverse effects on the slope. Numerical simulation analysis shows that under seismic conditions, the slope forms a pushing-type landslide, causing shear failure of the foundation soil with an impact depth of approximately 5 m. Considering the stability requirements of the slope and the damage to the foundation soil under seismic conditions, reinforcement measures such as anti-slide piles with grid anchoring were adopted to strengthen the slope, which have been applied to this project with good governance effectiveness. The analysis method and control measures can provide reference experience for the treatment of similar artificial excavation slope projects.