ISSN 1003-8035 CN 11-2852/P

    甘肃舟曲县果耶镇磨里滑坡成因及堵江危险性预测分析

    Analysis on the formation of the Moli landslide and river blockage risk in Guoye Town, Zhouqu County of Gansu Province

    • 摘要: 受降雨的影响,2021年2月26—28日,舟曲县果耶镇磨里滑坡发生蠕动变形,坡体裂缝发育,变形迹象明显,共造成92户402人受灾,直接经济损失约1 446.3万元。文中以舟曲县果耶镇磨里滑坡为研究对象,通过遥感解译、无人机航拍和地质勘察等方法,深入了解磨里滑坡所处的地质环境、土体物理力学性质等,对该滑坡的成因进行了详细分析、对滑坡的稳定进行了理论计算和位移监测分析。在野外调查和钻探分析的基础上,采用Massflow数值模型对舟曲县果耶镇磨里滑坡进行数值模拟与预测,确定物源区范围及厚度以预测滑坡的堆积过程和堵江风险,预测了滑坡堵江的高度、对上下游造成的危害。结果表明:(1)磨里滑坡呈长舌状,有清晰的形态和变形特征,滑体由碎石土和破碎千枚岩组成,平均深度40 m,总体积2 120×104  m3,属特大型深层滑坡。(2)不利的地形条件、岩土体的软化、强烈的构造运动、降雨的入渗和前缘河水冲刷下切形成的临空面是发生滑坡主要因素。(3)该滑坡存在摧毁房屋道路和堵江的风险,建议尽快对受威胁采取避险搬迁措施。本研究可为类似滑坡地质灾害链的成因机制和应急防控等提供参考。

       

      Abstract: Due to the heavy rainfall, from February 26th to 28th 2021, the Moli landslide in Guoye Town, Zhouqu County, experienced creeping deformation with the development of slope cracks and obnious signs of deformation. A total of of 92 households with 402 people were affected, causing a direct economic loss of approximately 14.463 million yuan. This study focuses on the Moli landslide in Guoye Town, where the geological environment and physical and mechanical properties of the soil were deeply understood through remote sensing interpretation, aerial photography, and geological investigation. The cause of the landslide formation was analyzed in detail, and the stability of the landslide was calculated theoretically and analyzed for displacement monitoring. Based on field investigation and drilling analysis, the Massflow numerical model was used to simulate and predict the Moli landslide in Guoye Town, Zhouqu County. The range and thickness of the source area were determined to predict the accumulation process of the landslide and the risk of river blocking. The height of the river blocking and the harm caused by the landslide to the upstream and downstream regions were predicted. The results showed that: (1) Moli landslide is a super-large deep landslide with a long tongue shape, clear shape and deformation, and composed of broken phyllite and broken stone soil. The average depth of the slide body is 40m, and the total volume is 21.2 million stere. (2) The main factors of landslide formation are unfavorable topographic conditions, softening of rock and soil, strong tectonic movement, rainfall infiltration, and front river erosion. (3) The landslide has the risk of destroying the landslide houses, roads, and blocking the river. It is suggested that the residents threatened by the Moli landslide should take measures to avoid danger and relocate as soon as possible. This study can provide reference for the formation mechanism and emergency prevention and control of similar landslide geological disaster chains.

       

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