ISSN 1003-8035 CN 11-2852/P

    坡面型泥石流运动特征模型试验

    Model tests on movement characteristics of debris flows on slope faces

    • 摘要: 坡面型泥石流是山区常见的一种地质灾害,启动模式与物源特征对其运动过程有重要影响。依托大理-瑞丽铁路大理西站工点典型的坡面型泥石流,开展室内缩尺模型试验,模拟平面式启动和滑坡式启动两种模式,以及考虑物源不同的粘稠性、颗粒级配、方量等因素进行了8组试验,得到了相应的坡面型泥石流运动特征。结果表明,坡面型泥石流的形成全过程呈现3个典型阶段:速度逐渐增大的启动阶段、速度略有下降的运动阶段、速度快速衰减的堆积阶段;稀性物源的启动速度大于黏性物源,泥石流运动速度随路程呈逐渐非线性减小趋势;泥石流对坡面的刮铲效应在坡面中上部较为强烈,最大刮铲深度占模型坡体表层厚度的60%;在坡脚处堆积物沿相应的冲出距离呈现一定的分选现象,细颗粒在距离坡脚更远的区域堆积。基于试验结果,建议坡面型泥石流工程防治以物源高低位分别沿坡高分为3区、2区进行,前者以限制顶部启动速度、减小坡面中上部刮铲效应为原则,后者以限制物源启动速度、坡脚强拦挡为原则。

       

      Abstract: Debris flows on slope faces represent a common geological hazard. The initial movement mode and resource characteristics significantly impact the movement process of the debris flow. Based on a typical case of debris flows on slope faces at Dali west railway station of the Dali -Ruili railway, a series of laboratory scaled model tests were conducted to investigate the movement characteristics of these debris flows. A total of eight sets of tests were performed, including start movement modes such as planar and landslide-type slides, as well as varying viscosity, particle gradation, and volume of the resources. The results reveal three typical formation stages of debris flows: a startup stage with progressively increasing velocity, a movement stage with slightly decreasing velocity, and an accumulation stage with rapidly reduced velocity. The start velocity of loose resources is higher than that of dense resources, and the movement velocity decreases nonlinearly with distance. The scrapping effect on the slope face is pronounced in the mid-upslope zone, with a maximum scrapping depth reaching 60% of the surface layer thickness in the slope model. Accumulated soils near the slope toe exhibit sorting characteristics along the rush distance, with fine particles accumulating further away from the slope toe. Based on the test results, it is suggested that three or two zones along the slope face can be divided to prevent the debris flow according to the height of the resources position. The principle for the former is to restrict the start velocity at the upslope and reduce the scrapping effect on the slope face, and the principle for the latter is to decrease the start velocity of the resources and construct strong retaining walls at the slope toe.

       

    /

    返回文章
    返回