公路扩建扰动下山区滑坡稳定性评价与防治措施

Stability Evaluation and Prevention Measures of Mountain Landslides under Highway Widening Disturbance

摘要: 山区公路扩建扰动常通过坡脚切坡削弱前缘支撑，叠加强降雨入渗易诱发残坡积土边坡复活滑动。以陆川县某一级公路段东侧山体为例，分析滑坡发育特征、形成机制、稳定性及治理措施。结果表明：研究区发育H1、H2、H3、H4四处滑坡及XP1隐患，滑体主要为第四系残坡积全风化砂质页岩，单体体积约4044.32~30789.6 m³，总规模约61713.25 m³。坡脚切坡形成临空面、强降雨入渗、软弱岩土遇水强度衰减及坡面长期裸露，是滑坡复活和扩展的主要原因。稳定性评价显示，暴雨工况下边坡稳定性明显降低，局部处于不稳定或欠稳定状态。治理宜采用削坡减载、锚索格构梁、截排水、复绿等综合措施；H2等剩余下滑力较大的滑坡，应结合抗滑桩桩板墙进行控制。研究成果可为类似工程防治措施提供参考。

Abstract: Highway widening in mountainous areas often weakens slope toe support through excavation disturbance. When coupled with intense rainfall infiltration, this process can easily induce reactivation and progressive failure of residual-soil slopes. Taking a landslide on the eastern mountain slope of a first-class highway section in Luchuan County as an example, this study analyzes its development characteristics, formation mechanism, stability condition, and mitigation measures. The results show that four landslides, namely H1, H2, H3, and H4, and one potential landslide area, XP1, have developed in the study area. The sliding mass is mainly composed of Quaternary residual fully weathered sandy shale, with individual volumes of approximately 4,044.32~30,789.6 m³ and a total volume of approximately 61,713.25 m³. The formation of a free face by slope toe excavation, intense rainfall infiltration, strength degradation of weak rock and soil after water exposure, and long-term exposure of the slope surface are the main causes of landslide reactivation and expansion. Stability evaluation indicates that the slope stability decreases significantly under rainstorm conditions, with some areas becoming unstable or marginally stable. Comprehensive mitigation measures, including slope cutting for unloading, anchor-cable lattice beams, drainage works, and revegetation, are recommended. For landslides with large residual sliding force, such as H2, anti-slide pile-slab walls should also be adopted. The findings may provide a reference for prevention and control measures in similar projects.