吉林大学学报(地球科学版)

• 地质工程与环境工程 • 上一篇    下一篇

2012年6·29贵州岑巩龙家坡滑坡灾害的基本特征与成因机理:一个由侧向剪切扰动诱发大型滑坡的典型案例

郑光1,许强1,林峰1,巨能攀1,邓茂林1,汪新芳2   

  1. 1.成都理工大学地质灾害防治与地质环境保护国家重点实验室,成都610051;
    2.四川省蜀通岩土工程公司,成都610041
  • 收稿日期:2013-10-13 出版日期:2014-05-26 发布日期:2014-05-26
  • 通讯作者: 许强(1968-),男,教授,博士生导师,主要从事地质灾害预测评价及防治处理方面的教学与研究工作 E-mail:xuqiang_68@126.com
  • 作者简介:郑光(1981-),男,博士研究生,主要从事地质灾害防治及模型试验工作,E-mail:flywing140@163.com
  • 基金资助:

    国家重点基础研究计划项目(2013CB733200);国家杰出青年科学基金项目(41225011);教育部长江学者特聘教授岗位资助项目(T2011186)

Characteristics and Failure Mechanism of the Longjiapo Landslide in Cengong,Guizhou on June 29,2012:A Case of Catastrophic Landslides Triggered by Lateral Shear Disturbance

Zheng Guang1,Xu Qiang1,Lin Feng1,Ju Nengpan1,Deng Maolin1,Wang Xinfang2   

  1. 1.State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu610051,China;
    2.Sichuan Shutong Geotechnical Engineering Company,Chengdu610041,China
  • Received:2013-10-13 Online:2014-05-26 Published:2014-05-26

摘要:

侧向剪切扰动诱发滑坡是一种新型滑坡类型,深入研究其成因机理,有助于开展滑坡预警工作。2012年6月29日6时20分左右,贵州省岑巩县思旸镇龙家坡山体发生大规模滑坡,300~400万 m3岩土体失稳后堵塞坡下的马坡河,形成20余 m高的堰塞坝及库容达7万余 m3的堰塞湖。笔者在对灾害现场进行详细地质调查的基础上,结合现场调绘、航拍、颗分试验等手段,对龙家坡滑坡的基本特征进行了分析研究,对滑坡发生及成灾原因进行了初步分析。结果表明:滑坡区风化破碎的厚层堆积体、有利的岩层倾向以及前缘临空是滑坡发生的基本条件;滑坡区南侧地下水径排区被堆填大量粉黏土弃渣,不仅为该区斜坡人为增加了巨大推力,还使该区斜坡地下水局部富集。在强降雨条件下,南侧堆积区首先发生滑动,其对主滑体的侧向剪切扰动作用带动主滑区大规模失稳破坏。由此,对这类侧向剪切扰动诱发的滑坡,在进行地质灾害调查和预警时,除了应调查其岩土体特征外,还必须查明其边界条件。

关键词: 龙家坡滑坡, 堆积体, 侧向剪切扰动, 堰塞坝, 成因机理, 地表破裂特征

Abstract:

As a new landslide type, its genetic mechanism of landslide is triggered by lateral shear disturbance. The large scale landslide occurred at Longjiapo,Cengong in Guizhou Province on June 29,2012. The landslide, with its volume ranging from 300×104 to 400×104 m3, became a 20 m weir dam in height blocking up the Mapo River in the lower part and a dammed-lake with about  7×104 m3 in volume. Based on site investigation, the authors provide detailed characteristics of the landslide and  analyze the mechanism of the landslide. It is combined with in-situ grain size composition experimentation, aerial photography and other means. The results indicate that, there were weathered thick accumulation body in the landslide area, and that inclination direction of rock stratum and terrain condition of slope were the favorable fundamental conditions to the landslide. The south part of slide areas, which was a natural guiding gutter of groundwater, had been filled in large amounts of silty clay. In that case, it exerted a large additive gravity force on the ground, and it also induced local groundwater enrichment in the slope body. After the rainfall, part of water seeped into the soil mass and reduced the shearing strength of soils. Then, the slope body in the south area slid firstly, and the motion took great lateral shear perturbation to the main slide area. The main slide area was driven to slide. It deserves intensive study as it is pretty special that the lateral shear disturbance triggered a large landslide. Hence, in addition to its characteristics of rock and soil in the landslide, the geo-conditions of both sides must be investigated in disaster early warning and mitigation.

Key words: Longjiapo landslide, accumulation body, lateral shear disturbance, weir dam, failure mechanism, characteristics of surface rupture

中图分类号: 

  • P642.22
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