川西凹陷地区中更新统冰水沉积滑坡稳定性分析

Stability analysis of Middle Pleistocene ice-water sediment landslides in the western Sichuan Depression

为了研究川西凹陷地区中更新统冰水沉积滑坡的变形破坏机制和稳定性,以G5京昆高速成雅段K1887+350滑坡为例,通过工程地质勘察和物理力学试验,运用综合监测技术,以滑坡的实际变形量为基础,分析了滑坡变形破坏机制,研究加固处治前后的滑坡稳定性。结果表明:不利的地质结构、前缘临空及降水诱发是K1887+350滑坡变形破坏失稳的主要原因,中更新统冰水沉积层细粒土的膨胀性进一步降低了土体抗剪性质,地表水长期渗润最终导致冰水沉积物浅表发生蠕动-拉裂变形;地表裂缝监测是判断山体变形趋势、分析滑坡稳定性的有效途径。

To study the deformation destruction mechanism and stability of the Middle Pleistocene ice-water sediment landslide in the western Sichuan Depression,this paper takes the K1887+350 landslide in the Chengdu-Yaan section of the G5 Beijing-Kunming Expressway as an example.Engineering geological surveys,physical and mechanical tests,and comprehensive monitoring are applied.Based on the actual deformation of the landslide,the paper analyzes the deformation and destruction mechanism of the landslide and studies the stability of the landslide before and after the reinforcement treatment and comprehensive monitoring technology.The results show that an unfavorable geological structure,slope toe,and precipitation induction are the main reasons for the deformation and instability of the K1887+350 landslide.The swell ability of fine-grained soil in the Middle Pleistocene ice-water sediment layer further reduces the soil shear properties.The long-term infiltration of atmospheric rainfall eventually leads to the superficial creeppull deformation of ice-water sediments.Surface crack monitoring is an effective way to judge the current state of a mountain and analyze the stability of a landslide.