中文摘要：

结合武汉市轨道交通2号线工程背景,采用现场监测和动力有限元数值模拟相结合的研究方法,对超浅埋通道下台阶爆破开挖地表振动传播规律进行研究。同时,为研究上台阶开挖空间对爆破地震波传播特征的影响,对通道全断面爆破开挖的地表振动传播规律进行数值模拟分析。研究结果表明：下台阶爆破开挖工况下,沿通道开挖导洞轴线方向,由于应力波的绕射,掌子面前方5 m处地表质点峰值振速达到最大值;垂直于通道开挖导洞轴线方向,掏槽孔孔底连心线中点正上方地表质点与爆源距离最小,但峰值振速并不是最大,且质点两侧2 m范围内,随着爆心距的增加,峰值振速不断增大。全断面爆破开挖工况下,沿通道开挖导洞轴线方向,掌子面前方2 m处地表质点峰值振速达到最大值;垂直于通道开挖导洞轴线方向,掏槽孔孔底连心线中点正上方地表质点峰值振速最大,且随着爆心距的增加,峰值振速不断减小。对比通道下台阶爆破开挖和全断面爆破开挖2种工况下地表质点振动特征,上台阶开挖空间的存在阻隔了应力波的传播,在一定空间范围内影响爆破地震波的传播特征,能够有效降低地表质点峰值振速。

英文摘要：

Combined with the blasting excavation of an ultra-shallow buried underpass in Wuhan Metro Line 2, field monitoring of blasting vibration and numerical simulation were used to study the propagation law of ground vibration induced by the blasting excavation of the lower bench. In order to investigate the influence of the upper bench to the propagation characteristic of blasting seismic wave, the propagation law of ground vibration induced by the blasting excavation of the full section was also studied by numerical simulation. The results show that in the condition of the blasting excavation of the lower bench, the maximum ground PPV reaches at 5 m ahead of working face along the axis of pilot because of the wave diffraction. In the direction normal to the axis of pilot, the maximum ground PPV does not occur at the point right above the center of cut holes＇ bottom, although it is the closest to explosion source, and within the range of 2 m away from the aforementioned point, the ground PPV increases continuously with an increasing distance to explosion source. Under the condition of the blasting excavation of the full section, the maximum ground PPV reaches at 2 m ahead of working face along the axis of pilot; the maximum ground PPV reaches at the point which is on the ground right above the center of cut holes＇ bottom in the direction normal to the axis of pilot, and the ground PPV decreases continuously with an increasing distance to explosion source. Comparing the ground vibration in the above 2 conditions, the excavation space of the underpass＇ s upper bench hinders the propagation of stress wave, and can lower the ground PPV effectively.