ISSN 1003-8035 CN 11-2852/P

    四川凉山州地质灾害灾情特征与主要致灾类型

    Characteristics of losses of geological disasters and major disaster types in Liangshan Prefecture, Sichuan Province

    • 摘要: 凉山州受活动构造、地形地貌、河流切割等作用,是四川省地质灾害高风险地区。为系统查明凉山州地质灾害发育特征、灾情特征及主要致灾类型,采用资料收集、数理统计、现场调查等方法,统计分析地质灾害数据、灾情数据和重大突发地质灾害实例。结果表明:凉山州地质灾害以滑坡、泥石流为主,滑坡主要为中小规模土质滑坡,泥石流主要为中小规模沟道型泥石流;有记录以来共计发生24起死亡10人以上的地质灾害;2006—2020年,共发生46起地质灾害灾情,以泥石流为主。总结提炼了7种地质灾害主要致灾类型,红层滑坡是凉山州滑坡主要类型之一,遇水易软化解体,自稳能力差;复活型古滑坡,在凉山州多有分布,由于人类工程活动、河流冲刷等因素,古滑坡易变形和复活;库岸型滑坡,主要发育在木里县、布拖县、宁南县的水电站库区内,受库水位消落带影响斜坡塌岸隐患较多,坡体稳定性降低形成滑坡;含煤层型滑坡,主要发育在凉山州南部的煤系地层区域,斜坡前缘不合理开挖易诱发前缘滑塌并造成整体滑动;矿渣型泥石流是凉山州泥石流主要类型之一,矿渣、废石、尾砂等不合理堆放,为泥石流提供了丰富物源;凉山州常发生森林火灾,火烧迹地遭遇暴雨后易诱发火后泥石流;在构造活动强烈、山势陡峭的沟谷上游发生崩滑灾害后,易沿沟运动冲出,堵塞河道形成链式灾害。研究成果可为凉山州针对性开展防灾减灾工作提供数据支撑和科学参考。

       

      Abstract: Due to active tectonics, topography, and river dynamics, Liangshan Prefecture is highly susceptible to geological disasters in Sichuan Province. In order to find out the developmental patterns, characteristics, and prevalent disaster modes of geological disasters in Liangshan Prefecture, this paper uses data collection, mathematical statistics, field investigation and other methods to conducted a comprehensive analysis of geological disaster data, disaster situations, and major sudden geological disaster cases in Liangshan Prefecture. The results show that the primary geological hazards in Liangshan Prefecture are landslides and mud-rock flows. The landslides are mainly medium and small scale soil landslides, and the mud-rock flows are mainly medium and small scale gully mudflows. Over the recorded period, Liangshan Prefecture experienced 23 geological disasters resulting in more than 10 fatalities. Between 2006 to 2020, 46 geological disasters occurred, mainly in the forms of debris flow. This paper identifies and refines seven typical geological disaster modes in Liangshan Prefecture. Notably, red bed landslides, prone to softening and disintegration in water with poor self-stability, constitute a significant landslide type. Reactivation of ancient landslides, widely distributed in the region, is triggered by human activities, river erosion, and other factors. Reservoir bank landslides are prevalent in the reservoir areas of Muli County, Butuo County, and Ningnan County, posing risks due to fluctuating reservoir water levels. There are many hidden dangers of bank collapse due to the influence of reservoir water level, and the slope Coal-bearing landslides are prominent in the southern coal measure stratum area, induced by unsustainable mining practices. Slag-type debris flow is one of the main types of debris flow in Liangshan Prefecture. The unreasonable stacking of slag, waste rock and tailings provides rich material sources for debris flow disasters. Liangshan Prefecture frequently experiences forest fires, and the burned land is easy to induce post-fire mud-rock flow after heavy rain. When the landslide disasters occurs in the upper reaches of gullies with strong tectonic activity and steep mountain potential, it is easy to rush out along the gully, blocking the river and forming a chain disaster. The research results can provide data support and scientific insights for disaster prevention and mitigation in Liangshan Prefecture.

       

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