铁路隧道爆破对地表振动响应研究

Study on Blasting Vibration response of underpass railway tunnel

在爆破开挖过程中,为确保新建隧道的安全施工,隧道上方地表振动问题亟需认真对待。依托某下穿铁路隧道爆破工程,对现场监测的振动数据进行回归拟合,建立爆破振动速度衰减方程,研究爆破作用下振动速度的传播规律;通过傅里叶变换进行爆破振动频谱特征分析,最后运用公式反算出隧道爆破所允许的单段最大装药量。使用ANSYS/LS-DYNA软件进行仿真模拟,通过实测结果检验数值模型建立的合理性。结果表明:模拟结果与监测结果吻合良好,可以开展后续的分析。运用数值模拟方法,研究掘进过程中隧道掌子面位置改变时,隧道爆破对地面振动响应影响的变化规律,确定隧道爆破振动的影响范围。结果发现:隧道掌子面位于质点后地面振动速度小于掌子面位于质点前振动速度;得出隧道掌子面前后控制爆破施工的安全距离。

In the process of blasting excavation,it is urgent to ensure the safe construction of the new tunnel and the ground vibration above the tunnel.In this paper,based on the blasting project of an underpass railway tunnel,the vibration data of the field monitoring are regression fitted,the attenuation equation of blasting vibration velocity is established,and the propagation law of vibration velocity under blasting is studied.Fourier transform is used to analyze the blasting vibration spectrum characteristics.Finally,the maximum charge of a single section allowed by tunnel blasting is calculated by inverse formula.ANSYS/LS-DYNA software was used for simulation,and the rationality of the numerical model was tested by the measured results.The results show that the simulation results are in good agreement with the monitoring results,and the follow-up analysis can be carried out.The numerical simulation method is used to study the change rule of the influence of tunnel blasting on ground vibration response when the position of the tunnel face changes during tunneling and determine the influence range of tunnel blasting vibration.The simulation results show that the ground vibration velocity of the tunnel with the face behind the particle is less than that of the tunnel with the face in front of the particle.According to the specification,the radius of the influence area before and after the tunnel face is 15.2 m and 18.2 m respectively.