落石冲击及对车桥的影响研究

发布时间：2018-04-25 23:29

本文选题：落石 + 冲击力　；参考：《西南交通大学》2017年硕士论文

【摘要】：由于线路平顺性以及展线的要求,西部山区线路的桥隧比较高。受地质条件影响,西部山区的山体滑坡以及落石现象较为严重,尤其是在汶川地震之后,落石撞击桥梁的现象时有发生,因此研究落石冲击以及对车桥的影响十分必要。本文依次就落石运动特性、落石冲击力计算以及落石-车-桥相互作用进行了研究。首先,根据相邻坡面的角度关系将坡面进行分类,并分析了落石在各类坡面类型中可能存在的运动形式,然后结合运动学理论对落石的运动过程进行计算分析,并与专业落石计算程序Rockfall的计算结果相对比以验证计算结果。其次,基于动力分析软件LS-DYNA对落石撞击桥梁结构进行数值仿真,计算不同冲击速度和不同冲击位置下落石的撞击力时程,将不同速度下落石的冲击力与规范公式的计算结果进行对比,验证落石撞击力模拟的准确性,在此基础上考查落石撞击作用下桥梁结构的响应。最后,采用软件BANSYS研究了落石冲击对车-桥系统动力性能的影响,分析了落石冲击作用下,桥梁结构动态响应以及列车的动态响应,并就冲击速度、冲击位置和列车位置等参数展开研究。结果表明:落石冲击力的平均值和最大值均随冲击速度的增加而增加,但由于冲击的持续时间也会随之增加,故冲击力的平均值并非如规范所规定的和落石速度成正比。冲击位置的不同对冲击力的最大值几乎没有影响,但随冲击位置的增高,冲击持时增加,导致冲击力的平均值降低。落石冲击作用下,列车横向加速度、轮轴横向力、轮重减载率、脱轨系数显著增大,但对竖向加速度影响很小;且冲击速度越大、冲击位置越高,对车辆响应的影响越显著。碰撞发生时,列车距离冲击点越近,列车的响应也会越大。
[Abstract]:The bridge and tunnel of the western mountainous area are relatively high due to the smoothness of the line and the requirements of the expansion of the route. Under the influence of geological conditions, the landslide and rock fall in the western mountainous area are serious, especially after the Wenchuan earthquake, the phenomenon of falling stone hitting the bridge occurs frequently, so it is very necessary to study the impact of falling stone and the impact on the vehicle and bridge. In this paper, the characteristics of rock falling motion, the calculation of rock falling impact force and the interaction between stone drop and vehicle-bridge are studied in turn. Firstly, according to the angle relation of adjacent slope, the slope surface is classified, and the movement forms of rock falling in various slope types are analyzed, and then the movement process of falling stone is calculated and analyzed by combining kinematics theory. The calculation results are compared with the results of the professional stone drop program Rockfall to verify the calculation results. Secondly, based on the dynamic analysis software LS-DYNA, the impact force time history of falling stone with different impact velocity and different impact position is calculated by numerical simulation. The impact force of falling stone at different velocities is compared with the calculated results of the standard formula to verify the accuracy of the impact force simulation of the falling stone, and the response of the bridge structure under the impact of the falling stone is examined on this basis. Finally, the influence of rock impact on the dynamic performance of vehicle-bridge system is studied by using software BANSYS. The dynamic response of bridge structure and the dynamic response of train under the impact of falling stone are analyzed, and the impact velocity is analyzed. The impact position and train position are studied. The results show that the average value and maximum value of impact force increase with the increase of impact velocity, but because the duration of impact will also increase, the average value of impact force is not in direct proportion to the velocity of falling stone as stipulated in the code. The difference of impact position has little effect on the maximum impact force, but with the increase of impact position, the impact duration increases, which results in the decrease of the average impact force. The lateral acceleration of the train, the lateral force of the axle, the load reduction rate of the wheel and the derailment coefficient increase significantly, but have little effect on the vertical acceleration, and the greater the impact speed, the higher the impact position, the more significant the impact on the vehicle response. When the collision occurs, the closer the train is to the impact point, the larger the train response will be.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441

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