青岗古滑坡体前缘开挖后局部复活特征及防治

古滑坡体自然状况下多处于稳定状态，但前缘受开挖扰动后，易发生复活变形。四川西南部某高速公路穿越青岗古滑坡体前缘，开挖后坡体发生局部复活变形，采用地质调绘、钻探、变形监测等手段，在查明古滑坡体及其复活变形区特征及成因的基础上，对古滑坡体进行了防治及效果监测。结果表明，古滑坡体前缘滑体土以含砾黏土、角砾土为主，其力学参数低，是局部复活的地质条件，前缘开挖临空及降雨是局部复活的诱因；在考虑施工快速可靠前提下，采用桩板墙+反压方案对滑坡体进行了及时、有效治理，避免了古滑坡体整体复活。研究成果可为后续公路等工程对古滑坡体前缘开挖扰动时提供勘察设计参考。

Characteristics and Prevention of Local Revival after Excavation of the Front Edge of the Qinggang Ancient Landslide Body

The ancient landslide body is generally in a stable state under natural conditions, but the front edge is prone to revive and deform after excavation. A certain highway in southwestern Sichuan Province passes through the front edge of the Qinggang ancient landslide body, and local revival deformation occurred after excavation. Through geological mapping, drilling, deformation monitoring, and other means, the characteristics and causes of the ancient landslide body and its revival deformation zone were investigated, and prevention and monitoring measures were implemented. The results show that the sliding soil in the front edge of the ancient landslide body is mainly composed of gravel clay and angular gravel soil, with low mechanical parameters, which is the geological condition for local revival. The excavation of the front edge and rainfall are the inducing factors for local revival. Under the premise of considering rapid and reliable construction, the pile-plate wall and counter-pressure scheme are adopted for timely and effective treatment of the landslide body, avoiding the overall revival of the ancient landslide body. The research results can provide survey and design references for the excavation disturbance of the front edge of ancient landslide bodies in subsequent highway and other engineering projects.