浅埋隧道爆破施工对地表建筑物安全的试验和数值分析

Experimental and numerical analysis on influence of blasting in shallow tunnel excavation on surface buildings

以沪昆高铁黄鹤堡隧道工程为研究对象,针对地表建筑物受大跨度浅埋隧道爆破开挖震动影响的情况,采用预裂爆破技术保护地表建筑物的安全。结合爆破震动监测,并利用FLAC3D进行隧道爆破开挖数值模拟,对隧道地表沉降及建筑物所处位置的质点振动速度进行分析,通过与现场实测数据进行对比发现：采用预裂爆破技术能够显著降低隧道地表质点最大振速,有效保护地表建筑物安全;隧道围岩等级越高,隧道地表沉降值越小,地表建筑物越安全;数值模拟监测点质点振动速度与现场实测的质点振动速度变化规律基本一致,振动时间少于1s,水平方向最大振速约为1.5 cm/s,垂直方向最大振速为1.6~1.7 cm/s,最大振速也比较接近。

Taking the Huanghepu tunnel engineering in the Shanghai-Kunming high-speed railway as research ob- ject, aiming at the situation that the surface buildings are usually influenced by the vibration of blasting excavation in large span shallow tunnel, the pre-splitting blasting technology was applied to ensure the safety of surface build- ings. Combined with blasting vibration monitoring, and carrying out numerical simulation of blasting excavation in tunnel by FLAC3D, the surface subsidence of tunnel and the particle vibration velocity in the positions of buildings were analyzed. By comparing with the field measured data, it showed that the pre-splitting blasting technology can effectively reduce the maximum particle vibration velocity on the ground surface of tunnel and protect the safety of surface buildings. The higher the surrounding rock grade, the lower the surface subsidence, and the safer the sur- face buildings. The variation laws of particle vibration velocity by numerical simulation and field measurement were almost consistent, the vibration time was less than 1 second, and the maximum vibration velocity was also close.