地铁隧道钻爆施工地表振动速度特征研究

为了研究地铁隧道爆破振动规律并有效地控制爆破振动危害,对贵阳地铁二号线一期工程隧道爆破开挖进行实时监测,然后对监测数据进行回归分析,计算出爆破地震波衰减系数α和k值,并利用大型有限元软件LS-DYNA对爆破施工进行数值模拟,结果表明:用萨道夫斯基公式对地铁隧道掘进的地表振动速度进行拟合时,隧道掘进前方比掘进后方的相关性较好,数值模拟计算所获得的地表振动速度规律与现场监测结果基本一致,地铁隧道掌子面后方已开挖区的地表振动速度存在放大现象。因此,在进行爆破施工方案设计时,必须考虑已开挖区的地表振动速度放大的影响,保障掌子面后方地表建筑物的安全。

Study on vibration velocity effects of ground induced by metro tunnel drilling and blasting construction

To study the law of blasting vibration of metro tunnel construction and effectively reduce the harm,real-time monitoring is conduct on the blasting excavation for the first-stage project of line 2 of Guiyang metro.The next procedure is to conduct regression analysis on the monitoring data,from which the coefficient for blasting wave attenuation could be figured out.Then the finite element software LS-DYNA is used to carry out numerical simulation on the blasting construction.Results have showed when the Sadaovsk formula is used to fit vibration velocity of ground surface during tunnel construction,the correlation works better in the front tunneling than the back one.The law for vibration velocity of ground surface in numerical simulation is basically the same from the on-site monitoring results.Amplification effect exists in the rear tunneling area of the tunnel face.For this reason,during the construction design,the amplification effect of vibration velocity at the ground surface should be taken into account to ensure the safety of the buildings above the surface of the tunnel face.