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Study on rolling motion mechanism of a rockfall on slope of weak ground

软弱地基边坡落石滚动运动机理研究

基本信息

批准号：
08650579
负责人：
MURO Tatsuro
金额：
$ 1.22万
依托单位：
Ehime University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650579/
关键词：
rockfall line motion model test soil slope slope gradient ratio of residual velocity to free fall slip ratio energy consumption 加速度等価摩擦係数転動軟弱地傾斜地衝撃加速度移動速度数値解析

项目摘要

The objective of the present research is to investigate the line-motion constants and the energy consumption of rockfalls in consideration of the sinkage. A series of laboratory experiments was executed in the combination of rockfall masses and slope gradients on a flat homogeneous slope made of Toyoura standard sand. The apparatus consisted of three main parts : a rockfall model, a soil bin arid a crane. The rockfall models made of steel and aluminum were columns having a diameter of 7.5, 10.0 and 12.5 cm and a width of 9.0 cm. The soil bin filled with the compacted soil had an effective length of 230 cm, a width of 30 cm and an effective depth of 25 cm. The rockfall models were dropped on the soil slope of the gradients ranging from 15 through 35 degrees.As a result, the conclusions are summarized as follows.1) The motion of the rockfall is uniform acceleration.2) Both the acceleration of the rockfall and the ratio of the residual velocity to free fall increase linearly with the slope gradient.3) Both the acceleration of the rockfall and the ratio of the residual velocity to free fall decrease with the rockfall mass on the soil slope because the motion resistance increases with the sinkage.4) Both the slip ratio in braking state and the kinetic energy ratio of the rotation to the translation decrease with thc slope gradient arid the rockfall mass.5) The ratios of the soil compaction energy to the potential increases considerably with the rockfall mass because the ratios of the kinetic energies to the potential decrease considerably.

本研究的目的是探讨线运动常数和能量消耗的落石考虑下沉。在丰浦标准砂组成的均质边坡上，进行了一系列崩塌体与边坡坡度组合的室内试验。该装置由落石模型、土槽和起重机三部分组成。由钢和铝制成的落石模型是直径为7.5、10.0和12.5cm、宽度为9.0cm的柱。填充有压实土壤的土箱的有效长度为230 cm，宽度为30 cm，有效深度为25 cm。将落石模型投放在坡度为15 ~ 35 °的土质边坡上，结果表明：（1）落石的运动为匀加速运动;（2）落石的加速度和剩余速度与自由落体的比值均随坡度的增大而线性增大;随着落石质量的增加，落石的加速度和剩余速度与自由落体的比值都减小，这是因为落石的运动阻力随着下沉量的增加而增加。随着坡度和落石质量的增加，滑坡体在制动状态下的滑移率和旋转动能与平移动能的比值均减小。随着落石质量的增加，土壤压实能与势能的比值显著增加，因为动能与势能的比值显著减小。