茂县滑坡的滑动机制与震后滑坡形成的地质条件

发布时间：2018-04-03 18:21

本文选题：茂县滑坡　切入点：几何形态　出处：《成都理工大学学报(自然科学版)》2017年04期

【摘要】：2017年6月24日在四川茂县新磨村发生高位巨型滑坡,是汶川地震后所发生的规模最大的一次岩质滑坡,滑坡体积巨大,破坏性强,造成了巨大的损失。基于现场调查资料和搜集的相关资料,描述了茂县滑坡的几何形态特征和沉积物特征,初步探讨了该区降雨条件、历史地震、活动断裂等特征及其对滑坡发生的影响,提出了茂县滑坡的滑动机制和动力学机制。主要成果包括:(1)茂县滑坡所在的富贵山处于松坪沟断裂和岷江断裂交汇和夹持的区域,显示为挤压型高陡(微)地貌,并具有"X"形平面断裂组合样式和"背冲式"剖面组合样式。(2)该区经历了多次强烈历史地震的影响,反复强烈的震动及叠加、累积变形破坏了岩体结构、坡面结构,降低了岩石的内聚力、摩擦强度和斜坡岩体的稳定性,并导致该区滑坡降雨阈值的降低,表明活动断裂及其历史地震是驱动茂县滑坡形成的主要控制因素,而降雨仅为诱发因素。(3)茂县滑坡的滑动模式为顺层拉裂-顺坡滑脱型模式,滑动过程可分为山体裂解阶段、高速溃滑阶段、碎屑流堆积阶段。在此基础上,提出了茂县滑坡的成因机制,主要表现在:高陡的单面山斜坡(顺层、顺坡)的临空条件是滑坡产生的势能条件;贯通性好的变质砂岩与板岩之间的滑动面(层面)是滑坡形成顺层拉裂-顺坡滑脱的滑动条件;富贵山两侧活动断裂对该山体的挤压抬升以及多次高强度历史地震的震动、变形的积累及其对岩体结构的长期破坏,是导致滑坡产生的地质条件。
[Abstract]:The giant landslide occurred in Xinmo Village, Maoxian County, Sichuan Province on June 24, 2017. It is the largest rock landslide occurred after the Wenchuan earthquake. The landslide is huge in volume and destructive, resulting in huge losses.Based on the field investigation data and relevant data collected, the geometric and sediment characteristics of Maoxian landslide are described, and the characteristics of rainfall conditions, historical earthquakes, active faults and their effects on the occurrence of landslides in this area are preliminarily discussed.The sliding mechanism and dynamic mechanism of Maoxian landslide are put forward.The main achievements include: (1) the Fugui Mountain, where the Maoxian landslide is located, is located in the area where the Sunpinggou and Minjiang faults meet and clamp, showing a compression-type high-steep (micro-) geomorphology.The area has experienced many strong historical earthquakes, repeated strong vibration and superposition, and cumulative deformation destroyed the rock mass structure and slope structure, and has the characteristics of "X" shape plane fault combination style and "back impact type" section combination style .2) the area has experienced many strong historical earthquakes, and repeated strong vibration and superposition, the cumulative deformation destroyed the rock mass structure and the slope structure.The cohesion of rock, the strength of friction and the stability of slope rock mass are reduced, and the rainfall threshold of landslide in this area is reduced, which indicates that the active fault and its historical earthquake are the main controlling factors driving the formation of Maoxian landslide.The slip model of Maoxian landslide is the model of along layer tension and sliding along slope, and the sliding process can be divided into three stages: the stage of mountain body cracking, the stage of high speed collapse and the stage of clastic flow accumulation.On this basis, the genetic mechanism of Maoxian landslide is put forward, which is mainly manifested in: the condition of the high and steep single-sided mountain slope (along the layer, along the slope) is the potential energy condition of the landslide;The slip surface (plane) between metamorphic sandstone and slate with good transfixibility is the sliding condition for the landslide to form along layer tension and sliding along slope, and the active faults on both sides of Fugui Mountain uplift the mountain body and shake many high intensity historical earthquakes.The accumulation of deformation and its long-term damage to rock mass structure are the geological conditions leading to landslide.
【作者单位】：油气藏地质及开发工程国家重点实验室(成都理工大学);资源环境信息系统国家重点实验室(中国科学院地理科学与资源研究所);四川省蜀通岩土工程公司;四川省地震局;渤海钻探井下技术服务分公司;
【基金】：国家自然科学基金项目(41525010,41472282,41502116,41372114,41340005,41172162)
【分类号】：P642.22

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