泥石流中漂木的运动和拦截特征

发布时间：2018-08-29 10:15

【摘要】：泥石流中携带的漂木往往具有很大的冲击破坏力,并且在沟道突缩处容易堵塞形成临时堵塞体造成严重的次生灾害。考虑漂木尺寸、漂木量以及泥石流密度等因素对漂木的影响,通过理论分析和模型试验研究了漂木的输移和在沟道突缩处的堵塞规律。通过理论分析和试验结果分析发现:漂木在泥石流流体表面向下游运动过程中由于两端受力不均匀会发生旋转使其长轴方向趋于平行于上游泥石流流向,这一现象随泥石流容重变小越明显;漂木尺寸对漂木拦截率有一定的影响,在漂木相对长度比L/B≤0.75时,对漂木拦截率影响较小,漂木被拦截的类型均为盲区停积型,漂木相对长度比0.75L/B1时,漂木拦截率增大,但是在漂木相对长度比L/B=1时,由于发生堵溃现象拦截率下降,随后漂木堵溃现象减弱,拦截率又逐渐增高,此时拦截类型主要为横向拦截型,理论分析和试验数据较一致;漂木量对漂木拦截率也有较大影响,在总体上,漂木拦截率随着漂木数量的增加而增加,当漂木数量N120时,被拦截数量较少,漂木的长度对其基本没有影响;漂木数量N120时,随着漂木数量的增大,多根漂木同时到达沟道突缩处的几率增大,漂木拦截率增大。综上可知,泥石流容重、漂木数量和漂木相对长度对漂木的堵塞均有较大影响,探讨漂木在泥石流中的输移和堵塞规律以及了解漂木致灾特征以及工程防治具有重要的指导意义。
[Abstract]:The driftwood carried in debris flow often has great impact destructive power, and it is easy to block and form temporary clogging body at the place where the channel suddenly shrinks and causes serious secondary disasters. Considering the influence of the size, quantity and debris flow density of the drift wood on the drift wood, the transport and blockage of the drift wood in the channel were studied by theoretical analysis and model test. Through theoretical analysis and experimental analysis, it is found that the long axis direction of drift wood tends to be parallel to the flow direction of debris flow upstream due to the uneven rotation of the two ends in the process of moving downstream of debris flow surface. This phenomenon is more obvious with the density of debris flow becoming smaller, and the size of driftwood has a certain influence on the interception rate of driftwood. When the relative length of driftwood is less than 0.75, it has little effect on the interception rate of driftwood, and the type of interception of driftwood is blind area stop type. When the relative length of bleached wood is higher than that of 0.75L/B1, the interception rate of bleached wood increases. However, when the ratio of relative length of bleached wood is L / B = 1, the interception rate of bleached wood decreases because of the phenomenon of blockage, and then decreases, and the interception rate increases gradually. At this time, the type of interception is mainly horizontal interception, and the theoretical analysis is consistent with the experimental data, and the amount of bleached wood also has a great influence on the interception rate of bleached wood. On the whole, the interception rate of bleached wood increases with the increase of the number of bleached wood, when the number of bleached wood is N120, With the increase of the number of bleached wood, the probability of multiple bleached wood reaching the corner of channel at the same time increased, and the interception rate of bleached wood increased with the increase of the number of bleached wood N120. In summary, the bulk density of debris flow, the number of driftwood and the relative length of driftwood have great influence on the blockage of driftwood. It is of great significance to discuss the transport and blockage of driftwood in debris flow and to understand the characteristics of drift-wood disaster and engineering prevention and control.
【作者单位】：中国科学院成都山地灾害与环境研究所中国科学院山地灾害与地表过程重点实验室;陕西工程勘察研究院;四川省核工业地质调查院;
【基金】：国家科技支撑计划课题“村镇地质灾害综合防治关键技术研究与示范”(2014BAL05B01) 国家自然科学基金“梯-潭结构型泥石流排导槽消能特性试验研究”(51641908)
【分类号】：P642.23

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