摘要
切向恢复系数是落石运动轨迹计算和被动防护系统设计的重要参数之一。通过不同坡面状态、落石形状和质量的落石模型冲击试验,进行落石碰撞切向恢复系数研究。结果表明:落石的形状对切向恢复系数无明显影响;落石质量、坡面状态、坡度、下落高度对切向恢复系数的影响较大,切向恢复系数随坡面由软到硬以及落石质量的增大而逐渐增大,随碰撞坡面坡度和下落高度的增大而逐渐减小;各种试验条件下切向恢复系数基本均在0.4以上,占总试验次数的98%,0.5以上的占93%,0.9以上的占25%,表明在碰撞过程中,落石切向速度的损失有限,在当前落石运动路径模拟中,现有切向恢复系数取值在部分情形下偏小,可能导致被动防护设计安全储备不足。综合考虑坡面状态和坡度2个因素,给出了不同条件下切向恢复系数的建议值。在实际取用时,坡面越硬、坡度越小则取区间内高值,反之,则取区间内低值,或直接采用区间随机取值。
The value of tangential restitution coefficient is the key parameter for calculating rockfall trajectories and designing passive protection systems.The tangential restitution coefficients were studied through rockfall collision tests under different conditions of slope,the shape and mass of rockfall.Results show that the tangential restitution coefficient is basically not affected by the shape of rockfall,and is obviously influenced by rockfall mass,slope conditions,gradient and falling height.The tangential restitution coefficient increases gradually as the slope changes from soft to hard or as the rockfall mass increases,and it decreases gradually with the increase of slope gradient or falling height.Most of the tangential restitution coefficients under various test conditions are above 0.4,which accounts for 98% of the total number of tests.The coefficients above 0.5 account for 93% of the total and those above 0.9 account for 25%,which indicates that the loss of tangential velocity is limited in the collision process.In the current simulation of rockfall movement path,the value of the existing tangential restitution coefficient is too small in some cases,which may lead to the lack of safety reserve in passive protection design.The suggested values for tangential restitution coefficients under various conditions are proposed by comprehensively considering slope state and gradient.It is suggested that higher value should be adopted when the slope is harder and the gradient is smaller.Otherwise,smaller value in the interval is taken or the interval random value is used directly.
出处
《中国铁道科学》
EI
CAS
CSCD
北大核心
2018年第1期8-15,共8页
China Railway Science
基金
国家自然科学基金资助项目(51108488
51408084
51679018)
国家重点研发计划重点专项子课题(2016YFC0802206-3)
重庆市高校青年骨干教师资助计划(渝教人[2011]65号)
重庆市高校创新团队建设计划资助项目(KJTD201305)
关键词
落石
运动路径
被动防护设计
切向恢复系数
模型试验
Rockfall. Trajectory
Passive protection design
Tangential restitution coefficient
Model test
