泥石流中漂木的运动和拦截特征
Movement and intercept characteristics of driftwood in debris flow
查看参考文献17篇
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文摘
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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0.75 < L/B < 1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N < 120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N > 120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。 |
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其他语种文摘
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[Background]Debris flow with woody could often have great impact destructive force,and threaten the safety of debris dams for woody debris may clog densely in the spillway. Judging from the results of past experiments related to driftwood in debris,we found that driftwood size,driftwood specific gravity,water depth,channel drop,and driftwood volume had a direct impact on the driftwood transport. [Methods]The model test tank device was selected as the rectangular section. A total of 75 kinds of test conditions under three kinds of debris flow bulk density,five kinds of driftwood number,and five kinds of L /B combination were designed. The experiment was conducted through 5 steps of 1) the model preparation 2) material configuration 3) test 4) change the debris flow bulk density,the number of driftwood (N) and the length of the driftwood,and repeat above 3 steps and 5) record the number of blocked driftwood. [Results]1) Driftwood tends to be parallel to the upstream debris flow direction due to the uneven forces acting on both sides of it,and transport to the downstream with a stable angle,this phenomenon is more obvious with the debris flow density becoming smaller. 2) The relative size of the driftwood has a certain effect on the intercept rate of the driftwood,and the effect on the intercept rate of the driftwood is small when relative length of driftwood L /B≤0.75 and driftwood intercept type is dead zone type. The intercept rate increases when 0.75 < L /B≤1,but the intercept rate decreases due to the occurrence of blocking phenomenon when L /B = 1,and then the intercept rate is gradually increasing because the blocking rate of driftwood is weakening. At this time,the intercept type is mainly key driftwood,and the theoretical analyses are consistent with experimental flume results. 3) The number of driftwood also has a great impact on the intercept rate,in general,the driftwood intercept rate increases with the number of driftwood increase. Driftwood intercept rate is very small and the size of the driftwood has little impact on the intercept rate when N≤120. With the increase of the number of driftwood,the probability of multiple driftwood reaching the channel shrinkage increases at the same time,and the intercept rate of driftwood increases when N > 120. [Conclusions] The bulk density of debris,the number of driftwood and the relative size of the driftwood cause the great impact on the intercept rate. The results show that studying pattern of the movement and intercept rate of driftwood in debris flow is of great significance for understanding the characteristics of driftwood disaster and engineering control. |
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来源
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中国水土保持科学（中英文）
,2017,15(6):9-18 【核心库】
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DOI
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10.16843/j.sswc.2017.06.002
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关键词
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泥石流
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沟道突缩
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漂木
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输移特征
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拦截率
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地址
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1.
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, 成都, 610041
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四川省核工业地质调查院, 成都, 610052
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语种
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中文 |
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文献类型
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研究性论文 |
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ISSN
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2096-2673 |
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学科
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水利工程 |
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基金
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国家科技支撑计划项目
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国家自然科学基金
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文献收藏号
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CSCD:6150719
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