循环爆破对在建桥梁的振动影响研究

Vibration impact of cyclic blasting on a bridge under construction

为了研究隧道循环爆破对邻近在建桥梁的振动影响,以贵州晴隆战马田的泄洪隧道工程为背景,对比了不同爆破方案下测点的峰值振速。通过FLAC3D软件建立三维模型,模拟了循环爆破对在建桥梁桥面、桥桩产生的振动影响。结果表明:4掏槽孔,0.42 kg/t装药密度及50 ms延时的爆破方案测点峰值振速最低,且循环进尺较高;桥面和桥桩底部的峰值振速实测值分别为0.235、0.081 cm/s,模拟值分别为0.250、0.095 cm/s,模拟值与实测值误差在±11%内,说明利用动荷载模拟循环爆破效果的模型有效;爆破施工对桥梁产生的峰值振速处于0.05~0.25 cm/s,对在建桥梁材料强度的影响处于安全范围内,表明每日8次的循环爆破对43 m外的在建桥梁不会产生安全影响。

In order to study the vibration impact of tunnel cyclic blasting on the adjacent bridge under construction,taking the flood discharge tunnel project in Zhanmatian,Qinglong,Guizhou Province as the background,the paper compares the peak vibration velocities of measuring points of different blasting schemes.It applies the three-dimensional model established by FLAC3D software to simulate the vibration impact of cyclic blasting on the deck and piles of the bridge.The results show that the blasting plan with 4 cutting holes,0.42 kg/t charge density and delay time of 50 ms has the lowest peak vibration velocities and higher cyclic footage.The measured values of the peak vibration velocities of the bridge deck and the bottom of the bridge piles are 0.235 and 0.081 cm/s,respectively,and the simulated values are 0.250 and 0.095 cm/s,respectively.The error between the simulated values and the measured values is within±11%,indicating that the model using dynamic load to simulate the impact of cyclic blasting is effective.The peak vibration velocity of the bridge caused by blasting is between 0.05 and 0.25 cm/s,and the impact on the material strength of the bridge under construction is within a safe range,indicating that 8 times of blasting a day will not have a safety impact on the bridge under construction at a distance of 43 m.