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落石的直线运动常数和能量消耗。在Toyoua标准砂构成的均质平坡上，进行了落石质量和坡度组合的一系列室内试验。该装置主要由落石模型、土槽和起重机三部分组成。落石模型由钢材和铝材制成，柱子直径分别为7.5、10.0和12.5厘米，宽度为9.0厘米。压实土的有效长度为230 cm，宽度为30 cm，有效深度为25 cm。落石模型落在坡度从15度到35度的土坡上。结果表明：1)落石运动为匀速加速运动；2)落石加速度和落石残速与自由落体之比均随坡度呈线性增加；3)落石加速度和落石残速与自由落体之比均随坡面上落石质量的增加而减小；4)制动状态下的滑移率和转动平动能比均随坡度和落石质量的增加而减小；5)土体压实能与自由落体之比随坡度和落石质量的增加而减小。随着落石质量的增加，势能显著增加，因为动能与势能之比显著降低。

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.