多次爆破荷载作用下大荒沟小净距隧道围岩岩体位移响应

Displacement responses of Dahuanggou surrounding rock with small clearance under blast loads

以丹东-通化高速公路大荒沟隧道进行的爆破振动监测数据为依据,采用FLAC-3D软件,分析了多次爆破荷载作用下大荒沟隧道小净距段围岩位移响应规律。根据爆破振动监测数据,考虑了竖向和横向质点运动在爆破荷载作用下的耦合效应,模拟左、右洞在6次爆破开挖下的隧道围岩位移响应,同时进行小净距隧道围岩岩体疲劳损伤声波监测,将爆破振动模拟结果和工程实测岩体疲劳损伤声波监测结果进行比较。分析表明:随着爆破循环开挖的进行,围岩处于稳定状态,在排除爆破加载左洞及右洞先后顺序的影响后,岩体损伤及围岩位移偏移以间柱为对称面呈现一定的对称性。同时,随着爆破掘进进行,隧道围岩监测处距爆破中心距离增大,测点处爆破应力波的强调度降低,围岩岩体疲劳损伤及位移偏移增量减少并最终趋于稳定。

Based on the blasting vibration monitoring data of Dahuanggou highway tunnels from Dandong to Tonghua,the FLAC-3D software was used to analyze the displacement responses of Dahuanggou tunnel surrounding rock with small clearance under blast loads.According to the monitoring data of the blasting vibration particles,the displacement responses of the surrounding rock,of which the left and right tunnels were subjected to circular blasting excavation with six times in all,were simulated by considering the coupling effect of the vertical and horizontal particle vibrations.And the acoustic wave velocities of the surrounding rock were experimentally measured.The simulated results were compared with the measured results.Comparisons show that with the progress of the circular blasting excavation,the surrounding rock is stable,and the damage and displacement offset of the surrounding rock take on certain symmetry by taking the middle column as an axis and getting rid of the effects of the blast load sequence undergone by the left and right tunnels.And with the progress of the blasting excavation,the distances of the monitoring points away from the explosion center increase,the blast-induced stress waves weaken at the monitoring points,the fatigue damage and displacement offset increment of the surrounding rock decrease and it tends to a stable state eventually.