地铁隧道TBM施工围岩振动效应的数值分析

为分析TBM施工地铁隧道引起的围岩振动效应及其影响,通过数值模拟并结合频谱分析方法,获得地表以及围岩振动的振速峰值和主振频率参数,分析不同掘进速度下TBM施工振动在地表和围岩中的分布,参考爆破安全规程给出的安全允许质点振动速度限值,评估振动影响范围。结果表明:在隧道轴线两侧6D(D为隧道直径)范围内TBM施工振动影响明显,超过6D范围后振动幅值较小,为振动微影响区;随着刀盘掘进速度降低,振速峰值减小,但二者不是线性关系;地表质点振动的主振频率一般在10～25　Hz范围,受掘进速度的影响不明显。

Numerical Analysis on Vibration Effect of Surrounding Rock Induced by TBM Excavation in Subway Tunnel

In order to analyze the vibration effect induced by subway tunnel construction by tunnel boring machine (short for TBM), the peak vibration velocity and the dominating vibration frequency of ground surface and surrounding rock were obtained by means of numerical simulation and spectrum analysis. The vibration effect under different TBM advance rates was analyzed, and an evaluation of the vibration influence range was given based on the Safety Specifications of Blasting Operation. It is concluded that the vibration effect is obvious within 6D(D is the tunnel diameter) away from the tunnel axis, and the vibration attenuates beyond the 6D range; as the TBM advance rate decreases, the peak vibration velocity also gradually reduces, however the peak vibration velocity is not simply in a linear relationship with the TBM advance rate; the dominating vibration frequency on the ground surface is generally between 10Hz to 25Hz, and it is unobviously affected by TBM advance rate.