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

本研究的目的是研究考虑下沉的岩崩的线动常数和能量消耗。在Toyoura标准砂构成的平坦均匀边坡上，进行了一系列岩崩体和坡度组合的实验室实验。该装置主要由三个部分组成：岩崩模型、土箱和起重机。由钢和铝制成的岩崩模型是直径为7.5、10.0和12.5厘米，宽度为9.0厘米的圆柱。填土槽有效长度为230 cm，宽度为30 cm，有效深度为25 cm。岩崩模型落在坡度为15 ~ 35度的土坡上。综上所述，本文的结论总结如下。1)落石运动为均匀加速度。2)落石加速度和剩余落石速度与自由落体的比值随坡度的增加呈线性增加。3)落石加速度和剩余落石速度与自由落体的比值随土质坡面落石质量的增大而减小，这是由于运动阻力随沉降量的增大而增大。(4)制动状态下的滑移比和旋转平移动能比随坡度和落石质量的增大而减小。5)土壤压实能与势能之比随岩崩质量的增大而显著增大，因为动能与势能之比显著减小。

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.