川西巴塘茶树山滑坡发育特征及形成机理

发布时间：2018-08-09 12:58

【摘要】：川西巴塘茶树山滑坡位于金沙江断裂带和巴塘断裂带的交汇处,区内地质构造复杂,新构造活动强烈,大型滑坡频发。茶树山滑坡为一古滑坡堆积体复活形成的滑坡。该滑坡自2001年7月首次出现滑动变形之后以蠕滑变形为主,不断的变形作用促使滑坡变形速度加快,滑坡体上出现了各种滑动形迹,于2006年1月7日发生大规模滑动。该滑坡目前仍处于不稳定状态,滑坡体变形破坏迹象较为明显,有进一步发生变形破坏的可能。在野外调查的基础上,对茶树山滑坡滑带土进行了大型直剪试验研究,获得了不同含水率条件下的滑带土抗剪强度变化规律,结果表明随含水率增大滑带土强度有明显减小的趋势。综合野外调查、物探钻探以及试验分析认为茶树山滑坡的形成机理为:受断裂构造作用,岩体结构面密集发育,岩体破碎程度高,岩土体力学性质差;上部透水层和下部隔水层的二元结构为滑坡体的富水提供了有利条件,强降雨作用使滑坡稳定性处于临界状态,渠水入渗和冻融作用直接诱发滑坡的发生。采用FLAC~(3D)对目前茶树山滑坡的稳定性进行模拟,结果表明,在强降雨条件下滑坡体出现明显的变形迹象,滑移面即将贯通,可能再次发生大的滑动。从滑坡形成机理角度考虑,加强排水、避免渠水再次入渗可以有效地控制坡体稳定性。
[Abstract]:Batang Chashan landslide in western Sichuan is located at the junction of Jinshajiang fault zone and Batang fault zone. The geological structure in the area is complex, the neotectonic activity is strong, and large-scale landslides occur frequently. The Cha-Shu Shan landslide is a landslide formed by the revival of an ancient landslide accumulation. Since the first sliding deformation occurred in July 2001, the landslide was dominated by creep deformation, which was accelerated by the continuous deformation, and a variety of slippage signs appeared on the landslide body, and a large-scale slide occurred on January 7, 2006. The landslide is still in an unstable state at present, and the signs of deformation and failure of the landslide body are obvious, and there is a possibility of further deformation and failure. On the basis of field investigation, a large scale direct shear test was carried out on the sliding zone soil of the Cazushan landslide, and the shear strength of the sliding zone soil under different moisture content was obtained. The results show that the strength of sliding zone soil decreases obviously with the increase of moisture content. Comprehensive field investigation, geophysical drilling and experimental analysis show that the formation mechanism of the Cazushan landslide is as follows: by the action of fault structure, the structure of rock mass is dense, the degree of rock mass fragmentation is high, and the physical properties of rock and soil are poor; The dual structure of the upper permeable layer and the lower water-isolated layer provides favorable conditions for the water-rich landslide. The landslide stability is critical due to the strong rainfall and the infiltration of canal water and freeze-thaw process directly induce the occurrence of the landslide. FLAC3D is used to simulate the stability of the current Cashushan landslide. The results show that under the heavy rainfall conditions, the landslide body appears obvious deformation signs, the slip surface is about to be through, and the large slip may occur again. Considering the formation mechanism of landslide, the stability of slope can be effectively controlled by strengthening drainage and avoiding re-infiltration of canal water.
【作者单位】：中国地质大学(北京);中国地质科学院地质力学研究所;国土资源部新构造运动与地质灾害重点实验室;
【基金】：中国地质调查局项目(12120113038000) 国家自然科学基金项目(41402321) 科技部科技基础性工作专项(2011FY110100-2) 中铁二院科研计划(二院科字201303)
【分类号】：P642.22

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