永善县城古滑坡复活变形特征及稳定性分析

永善县城所处单斜斜坡整个为一古滑坡堆积体,位于金沙江南部。自1979年开始至今,古滑坡东部H1、H2滑坡分别发生复活变形,严重威胁复活滑坡上部永善县城3.5万余人生命财产安全。本次研究采用地面调查、地表与地下位移监测以及数值模拟等方法,分析了永善县城东部滑坡的复活变形特征与不同工况下复活滑坡稳定性的变化特征。结果表明：永善县城古滑坡深层特大型滑坡,现阶段复活的H1滑坡变形迹象明显,其中以北东侧变形最为剧烈,平均水平位移速率达0.63mm/d,H1整体处于加速变形阶段;H2滑坡处于蠕动变形阶段,后缘局部发育小型拉张裂缝。复活滑坡存在三个滑动面：H1滑坡第一剪出口、H1滑坡第二剪出口、H2滑坡,通过极限平衡法中的M-P法与Spencer法对不同工况下滑坡的稳定性进行分析与评价,得出数值模拟的稳定性特征与监测变形特征基本一致,暴雨对滑坡复活变形的影响最大、地震次之,因此后期治理需要充分考虑分区域治理与截排水的问题。

Analysis on the Reactivation Deformation Characteristics and Stability of Ancient Landslide in Yongshan County

The monocline slope of Yongshan county is an ancient landslide accumulation body, located in the south of Jinsha River. Since 1979, the H1 and H2 landslides in the eastern part of the ancient landslide have revived and deformed respectively, seriously threatening the safety of more than 35,000 people"s lives and property in Yongshan County on the upper part of the revived landslide. In this study, surface investigation, surface and underground displacement monitoring and numerical simulation methods were used to analyze the characteristics of revived landslide deformation and stability of revived landslide under different working conditions in the east of Yongshan county. The results show that the deformation of the resurrected H1 landslide is obvious at the present stage, and the deformation of the north and east side is the most severe, with an average horizontal displacement rate of 0.63mm/d. H1 is in the accelerated deformation stage as a whole. H2 landslide is in the stage of creep deformation, and small tensile cracks are locally developed at the back edge. There are three sliding surfaces in reviving landslide: The first shear outlet of H1 landslide, the second shear outlet of H1 landslide, and the H2 landslide were analyzed and evaluated by M-P method and Spencer method in limit equilibrium method under different working conditions. It was concluded that the stability characteristics of numerical simulation were basically consistent with the deformation characteristics of monitoring. Heavy rain had the greatest influence on the landslide resurrection deformation, followed by earthquake. Therefore, the problems of sub-regional governance and interception and drainage need to be fully considered in the later treatment.