Mechanism and discharge prediction of the debris flow that is induced by a landslide

滑坡泥石流发生机理及流量预测

基本信息

批准号：
10480094
负责人：
TAKAHASHI Tamotsu
金额：
$ 6.53万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10480094/
关键词：
landslide slip liquefaction debris flow scale prediction experiment numerical simulation

项目摘要

Recently in Japan, large scale debris flow that is induced by landslide often occurs. But, the discharge and the hazardous area of that kind of debris flow cannot be predicted, because, at the moment, there is no predictive model. This investigation aims to present a predictive model of viscous debris flow generated by a landslide.Whether the debris flow is induced in contractive soils or in dilative soils may require different way of water supply that is necessary to fill up the void space among particles in debris flow. Here, the landslide is assumed to occur in dilative soil block by the appearance of saturated soil layer near the slip surface.A test piece of dilative soil that contains plenty of water was prepared in a steep experimental flume, and it was released to move down slope. The lower saturated layer was liquefied by shearing, and it was left behind the soil block as debris flow. The soil block becomes thinner and thinner with its advance down the slope, and the total volume of debris flow left behind increases.The speed of liquefaction was given as a function of water content and shearing rate, and a system of equations that describes the motion of the soil block was obtained. The validity of the theory was proved by comparing the theoretical results with experiments. Another system of equations that is able to predict not only the motion of soil block but the motion of debris flow even after stoppage of the soil block is obtained. The Harihara River debris flow that is a typical landslide induced debris flow will be reproduced numerically using the newly developed theory.

近年来，日本经常发生因滑坡引发的大规模泥石流。但这种泥石流的流量和危险区域无法预测，因为目前还没有预测模型。本研究旨在提出滑坡产生的粘性泥石流的预测模型。无论是在收缩性土壤中还是在膨胀性土壤中引发泥石流，都可能需要不同的供水方式来填充碎片中颗粒之间的空隙空间流动。这里，通过滑面附近出现饱和土层，假定滑坡发生在膨胀土块中。在陡峭的实验槽中准备一块含有大量水的膨胀土试块，并将其释放向下移动坡。下饱和层因剪切而液化，并以泥石流形式留在土块后面。土块随着沿斜坡的推进而变得越来越薄，留下的泥石流总体积不断增加。液化速度是含水量和剪切速率的函数，并有一个描述运动的方程组获得了土块。通过理论结果与实验的比较，证明了理论的有效性。获得了另一个方程组，该方程组不仅能够预测土块的运动，而且即使在土块停止后也能够预测泥石流的运动。哈里原河泥石流是一种典型的滑坡引发的泥石流，将利用新开发的理论进行数值再现。