Coefficient of restitution and kinetic energy loss of rockfall impacts
Coefficient of restitution and kinetic energy loss of rockfall impacts
复制标题
落石冲击的恢复系数和动能损失
DOI：
10.1007/s12205-015-0221-7
复制
发表时间：
2016
影响因子：
2.2
通讯作者：
Shi Shao-shuai
中科院分区：
文献类型：
--
作者：
Li Li-ping;Sun Shang-qu;Li Shu-cai;Zhang Qian-qing;Hu Cong;Shi Shao-shuai
本文介绍了岩落冲击的两个关键参数恢复系数和动能损失率的室内试验结果。然而，关于恢复系数的定义多种多样，至今还没有形成和得到最合适的定义。此外，岩崩冲击过程中的能量变化对实际设计具有重要意义。本研究在实验室测试中采用板形和条形两种形状的砌块，并对砌块材料进行了测试，表明该材料具有足够的强度，可以防止在冲击过程中破碎。此外，还建立了一个专门为本研究建造的装置，包括一个底座、一个斜坡和一个释放装置。采用板块和条形块进行跌落试验，试验过程中改变跌落高度、坡角和释放高度，评估各参数对恢复系数和能量损失率的影响。观察到碰撞反射角均小于碰撞角，说明碰撞过程中存在能量损失。冲击角随坡角的增大而减小，而释放高度和释放角对冲击角的影响不明显。随着冲击角度的增大，相关恢复系数减小，动能损失率增大。最后，发现撞击前后的动能对COR和能量损失率有显著影响，可以为减灾措施提供依据。
This paper presents the results of the coefficient of restitution and the kinetic energy loss rate obtained by lab experiment, two parameters that are crucial for rockfall impact. However, various definitions of coefficient of restitution exist and the most appropriate one is still not formed and obtained. In addition, the energy variation during the rockfall impacts has important significance in practical design. In this research, two kind shapes of blocks including plate and strip were adopted in the laboratory testing and the block material was tested before, indicating that the material has sufficient strength to prevent shattering during the impact. Furthermore, an apparatus specifically built for this study was established including a base, a slope and a releasing device. The falling testing was performed using plate and strip block while the falling height as well as the slope angle and releasing height were altered during the tests in order to estimate the effect of each parameter on the coefficients of restitution and energy loss rate. It was observed that collision reflection angle is less than impact angle for all, suggesting energy loss in collision. Impact angle decreases with increasing slope angle while there was no obvious effect of releasing height and releasing angle on impact angle. The relevant coefficient of restitution was found to decrease with impact angle, and the kinetic energy loss rate increased. Finally, the kinetic energy before and after the impact was found to significantly affect the COR and energy loss rate and the results can provide basis for mitigation measures.