ISSN 1003-8035 CN 11-2852/P

    基于滑坡破坏模式分析的易发性评价以三峡库区首段泄滩河左岸为例

    Evaluation of landslide susceptibility based on landslide failure mode analysis: A case study of the left bank of Xietan River in the first section of Three Gorges Reservoir

    • 摘要: 三峡库区首段发育有大量岩质滑坡,其中很多灾害点极具隐蔽性且目前并未被查明。文中以三峡库区首段泄滩河左岸为研究区,以区内唯一破坏的卡门子湾顺层岩质滑坡为例,在分析其成因机制的基础上归纳总结了该地区顺层岩质滑坡的破坏模式,并以此确定了高程、坡度、坡向、起伏度、平面曲率、剖面曲率、地层岩性、距河流距离及距道路距离共9个评价指标因子及疑似滑坡隐患点,将这些灾害隐患点作为滑坡样本,运用ALSA模型开展研究区的滑坡易发性分区,最后采用ROC曲线及现场复查等方法验证评价结果的可靠性。预测结果表明:研究区内顺层岩质滑坡的极高易发区和较高易发区大致呈面状分布,主要集中在岩性为侏罗系中统上沙溪庙组紫红色泥岩夹砂岩和西北坡向的近库岸地区。现场验证发现易发分区结果与滑坡破坏模式分布规律较吻合,表明基于滑坡破坏模式选择滑坡样本得到的滑坡易发性结果在整体上也能反映研究区滑坡概率空间分布规律,在缺乏准确滑坡样本时可作为一种替补方案。上述研究结果为基于滑坡破坏模式选取滑坡样本开展易发性评价工作提供了理论支持和科学依据。

       

      Abstract: There are a large number of rock landslide disasters developed in the first section of the Three Gorges Reservoir area, many of which are very hidden and have not been identified. In this paper, taking the left bank of Xietan River in the first section of the Three Gorges Reservoir as the study area, taking the only bedding rock landslide in Kamenziwan as an example, the failure mode of bedding rock landslide in this area is summarized on the basis of analyzing its genesis mechanism. Nine evaluation index factors, including elevation, slope aspect, slope, relief, plane curvature, profile curvature, formation lithology, distance from river and distance from road, as well as suspected hidden danger points of landslide disaster are determined. These hidden danger points are taken as landslide samples. Automatic Landside Susceptibility Assessment Model (ALSA) was used to carry out landslide Susceptibility zoning in the study area. Finally, ROC curve and field review were used to verify the reliability of the evaluation results. The prediction results show that the extremely high and highly prone areas of bedding rock landslides in the study area are distributed in a plane shape, mainly concentrated in the middle Jurassic Upper Shaximiao Formation purplish red mudstone intercalated sandstone, and the northwest slope direction near the reservoir bank area. Field verification shows that the results of prone zoning are consistent with the distribution law of landslide failure mode, indicating that the landslide susceptibility results obtained by selecting landslide samples based on landslide failure mode can also reflect the spatial distribution law of landslide probability in the study area on the whole, and can be used as a substitute scheme in the absence of accurate landslide samples. The above research results provide theoretical support and scientific basis for selecting landslide samples to carry out vulnerability assessment based on landslide failure mode.

       

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