隧道爆破及车辆荷载耦合作用下公路振动研究

针对隧道下穿环城公路爆破开挖产生的振动效应,同时考虑公路上车辆瞬时荷载耦合作用,运用LS-DYNA分析环城公路的振动规律及响应特征,并与实际监测结果进行对比分析,研究结果表明:(1)公路中部位置的峰值应力为1.7 MPa,大于两边的峰值应力,随着爆破点与路面间水平距离的增大,峰值应力也逐渐增大;(2)在0.015 s到0.02 s这段时间内,振速幅值最大,随后,幅值降低,振动频率变小,振动趋于缓和,数值模拟的结果要普遍小于实际监测的振速峰值;(3)公路左侧振动的位移响应最大,但是公路中部位置会在之后的振动过程中产生二次峰值,造成更大的位移响应。研究可为相似工程设计提供一个参考。

Research on Numerical Behavior of Highway Vibration under the Coupling Action of Tunnel Blasting and Vehicle Load

Aiming at the vibration effect caused by the blasting excavation of the tunnel underpass the ring road, and considering the coupling effect of the instantaneous load of vehicles on the road, the vibration law and response characteristics of the ring road is analyzed in LS-DYNA. Compared with the actual monitoring results, the result shows: (1) the peak stress in the middle of the highway is 1.7 MPa, which is greater than the peak stress on both sides. As the horizontal distance between the blasting point and the road increases, the peak stress gradually increases. (2) During the period from 0.015 s to 0.02 s, the amplitude of the vibration velocity is the largest. Subsequently, the amplitude decreases, the vibration frequency becomes smaller, and the vibration tends to ease. The vibration speed results of numerical simulation are generally smaller than the results of actual monitored value. (3) The displacement response of the vibration on the left side of the road is the largest, but the middle position of the road will produce a secondary peak in the subsequent vibration process, resulting in a greater displacement response. The research can provide a reference for the following similar engineering design.