【摘要】 以紧邻既有隧道上方开挖爆破工程为例,通过现场爆破试验和数值模拟,分析爆破振动作用下既有隧道结构动力响应特性。由爆破试验结果可知:质点垂向峰值振速对爆破振动控制起主要作用;采用回归分析得到的质点垂向峰值振速经验公式,对不同最大单段药量时的质点垂向峰值振速预测的平均误差率为11.86%。数值模拟结果表明:隧道直墙底脚位置单元的垂向峰值振速为4.36cm.s-1,水平向峰值振速为3.72cm.s-1,隧道拱顶处的垂向峰值振速为4.13cm.s-1,均在安全振速控制值范围之内;相邻位置的隧道围岩与衬砌结构的受力及质点峰值振速均不一致,且振速衰减趋势也存在差异性。现场试验结果验证了数值模拟结果的正确性,而且数值模拟的爆破振动作用下隧道动力响应具有更高的精度。更多还原

【Abstract】 Based on the excavation blasting project adjacent to the top of the existing railway tunnel,the dynamic response characteristics of the existing tunnel structure subjected to blasting vibration were analyzed by field blasting tests and numerical simulation.The blasting test results indicate that the particle vertical peak vibration velocity plays a main role in blasting vibration control.When the particle vertical peak vibration velocity is predicted by the empirical formula which is based on regression analysis,the average error rate of prediction is 11.86% for different maximum charge of single segment.The numerical simulation results indicate that the particle vertical peak vibration velocity on the foot of tunnel vertical wall is 4.36 cm·s-1,and the particle horizontal peak vibration velocity is 3.72 cm·s-1.The particle vertical peak vibration velocity on the tunnel vault is 4.13 cm·s-1.They are all within the control values of safety vibration velocity.There is the inconsistence of the particle peak vibration velocity and peak effective tensile stress in the lining and surrounding rock at the junction of arch and wall,and the attenuation trends of vibration velocity are different.The correctness of numerical simulation has been proved by field test results,and the simulation results of existing tunnel structure dynamic response subjected to vibration velocity are more accurate.更多还原