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现代地质 ›› 2024, Vol. 38 ›› Issue (02): 451-463.DOI: 10.19657/j.geoscience.1000-8527.2023.090

• 水文地质、工程地质和环境地质 • 上一篇    下一篇

金沙江上游沙丁麦大型古滑坡发育特征与稳定性评价

邱振东1,2,3(), 郭长宝1,3(), 吴瑞安1,3, 简文星2, 倪嘉伟1,3, 张亚楠1,2,3, 闫怡秋1,3   

  1. 1.中国地质科学院地质力学研究所,北京 100081
    2.中国地质大学(武汉)工程学院,湖北 武汉 430074
    3.自然资源部活动构造与地质安全重点实验室,北京 100081
  • 收稿日期:2023-04-07 修回日期:2023-07-12 出版日期:2024-04-10 发布日期:2024-05-22
  • 通讯作者: 郭长宝,男,研究员,1980年出生,地质工程专业,主要从事地质灾害方面的研究。Email: guochangbao@163.com。
  • 作者简介:邱振东,男,硕士研究生,1998年出生,地质工程专业,主要从事地质灾害评价工作。Email: qiuzhendong@cug.edu.cn
  • 基金资助:
    国家自然科学基金青年科学基金项目(42207233);中国地质调查局地质调查项目(DD20190319);中国地质调查局地质调查项目(DD20221816)

Development Characteristics and Stability Evaluation of the Shadingmai Large-scale Ancient Landslide in the Upper Reaches of Jinsha River, Tibetan Plateau

QIU Zhendong1,2,3(), GUO Changbao1,3(), WU Rui’an1,3, JIAN Wenxing2, NI Jiawei1,3, ZHANG Ya’nan1,2,3, YAN Yiqiu1,3   

  1. 1. Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China
    2. Faculty of Engineering, China University of Geosciences (Wuhan), Wuhan, Hubei 430074, China
    3. Key Laboratory of Active Tectonics and Geological Safety, Ministry of Natural Resources, Beijing 100081, China
  • Received:2023-04-07 Revised:2023-07-12 Online:2024-04-10 Published:2024-05-22

摘要:

沙丁麦古滑坡位于金沙江上游,金沙江断裂的德工—射胆断裂从滑体前部通过,岩体结构破碎,加上区域降雨、人类活动影响,滑坡变形强烈,坡体存在失稳滑动的风险,严重威胁到当地居民生命财产以及金沙江上游重要交通设施等。为探究沙丁麦古滑坡的发育特征及滑坡稳定性等关键问题,本文对沙丁麦古滑坡开展了遥感解译、InSAR形变监测、降雨量数据分析以及滑坡稳定性数值模拟计算等研究,揭示滑坡目前的变形特征,并探讨不同数值模拟工况下的滑坡稳定性。结果表明,沙丁麦古滑坡长约2100 m,宽约1300 m,平均厚度15~20 m,体积为2180×104~2900×104 m3,属于特大型堆积层滑坡。空间上可划分为古滑坡后缘区 (I)、古滑坡堆积区 (Ⅱ) 和强变形区 (Ⅲ) 三个区域,其中强变形区中包含两个复活变形区 (Ⅲ1、Ⅲ2)。沙丁麦古滑坡以拉张裂缝、房屋开裂、下错陡坎、局部滑塌等变形现象为主。基于小基线集合成孔径雷达干涉测量 (SBAS-InSAR) 的监测结果显示,沙丁麦古滑坡地表最大形变速率可达-51.88 mm/a。结合区域降雨数据的分析结果反映滑坡体累计变形量呈“阶跃”式增长,强降雨是影响滑坡堆积体变形的重要因素之一。基于三维快速拉格朗日分析法 (FLAC3D) 的古滑坡稳定性计算结果表明,沙丁麦古滑坡的变形模式为牵引式,天然工况下滑坡整体处于基本稳定状态,坡体形变量较小;在极端暴雨工况下滑坡总体上处于不稳定状态,滑坡体变形表现为拉张、剪切破坏,滑动面贯通并发生整体失稳破坏,从而造成严重危害。

关键词: 金沙江上游, 沙丁麦, 古滑坡, 变形监测, 数值模拟

Abstract:

The Shadingmai ancient landslide is located in the upper reaches of the Jinsha River. The Degong-Shedan Fault from the Jinsha River Fault system passes through the front part of the landslide, causing a large scale of rock fractures. Combined with the effects of regional rainfall and human activities, the landslide experiences an intense deformation, posing a risk of unstable sliding. This causes a serious threat to the lives, properties of residents, and critical transportation in the upstream region of the Jinsha River. To investigate the key issues such as the developmental characteristics and stability of the Shadingmai ancient landslide, this study conducted remote sensing interpretations, InSAR deformation monitoring, rainfall analysis, and numerical simulation of landslide stability for the landslide. The study investigated the current deformation characteristics of the landslide and explored its stability under different conditions. The research results indicate that the Shadingmai ancient landslide is approximately 2,100 m long and 1,300 m wide, with a thickness of approximately 15-20 m. Its volume ranges from 2,180×104 to 2,900×104 m3, making it a super-large accumulation landslide. In terms of its spatial distribution, it can be divided into three regions, as the ancient landslide rear edge region (Ⅰ), the ancient landslide accumulation region (Ⅱ), and the strong deformation region (Ⅲ), which further includes two reactivated deformation zones (Ⅲ1 and Ⅲ2). The main deformation phenomena of the landslide included tensional cracks, building fissures, steep displacement faults, and localized collapses. Based on SBAS-InSAR monitoring results, the maximum surface deformation rate reaches to -51.88 mm/a. Combined with the regional rainfall data, the cumulative deformation of the landslide exhibits a ‘step’ growth pattern. Heavy rainfall is one of the significant factors influencing the deformation of the landslide mass. The stability calculation of the landslide using FLAC3D shows that the deformation mode is characterized by retrogressive deformation. Under natural conditions, the landslide is in a relatively stable state with minimal slope deformation. However, under extreme heavy rainfall conditions, the landslide becomes unstable, exhibiting tension and shear failures, with the sliding surface penetrating and causing overall instability and significant hazards.

Key words: upper reaches of the Jinsha River, Shadingmai, ancient landslide, deformation monitoring, numerical simulation

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