【摘要】 盾构切削“上土下岩”复合地层时，刀盘-土岩作用面上会发生强烈振动，这种振动在土层中向四周传播，对周边地上地下建(构)筑物造成不利影响。本文通过三维动力有限元与无限元边界的耦合模拟及现场振动测试，对盾构掘进过程中刀盘切削振动在地层空间上的分布与传播规律进行理论与实测研究，得到如下主要结论：(1)数值模拟结果表明，盾构切削振动引起的周边地层振动响应沿开挖面侧向急速衰减，衰减曲线呈指数函数形式；沿隧道轴线则先增强后衰减，在距离开挖面0.5倍盾构直径处，振动响应达到最大，约为开挖面处的2.28倍；(2)盾构切削振动在不同地层中的衰减速率表现为：粉质黏土>强风化闪长岩>中风化闪长岩，这与振动在不同地层中传播时在节理面及间隙处的反射/透射能量的大小密切相关；(3)现场实测结果表明，理论模拟与实测分析规律较吻合，验证了本文数值模型及上述分析结论的合理性。本文所得结论可为盾构隧道在复合地层中的合理选线及切削振动控制提供参考。更多还原

【Abstract】 During shield tunneling through composite strata of overlying soil and underlying rock,intense vibrations occur at the cutterhead-soil/rock interface.These vibrations propagate through the upper soil layer and may adversely affect surrounding underground and surface structures.Three-dimensional dynamic finite element simulations and field vibration tests were conducted to investigate the spatial distribution and propagation patterns of vibration responses caused by cutter head vibrations were analyzed.The main conclusions are as follows:(1) Numerical simulation results indicate that the vibration response in the surrounding strata rapidly attenuates laterally from the excavation face,following an exponential decay curve.Along the tunnel axis,the vibration response initially increases and then decreases,reaching a peak at a distance of 0.5 times the shield diameter from the excavation face,approximately 2.28 times that at the excavation face.(2) The attenuation rates of shield-cutting vibrations vary across different strata,with silty clay exhibiting the highest rate,followed by highly weathered diorite and moderately weathered diorite.This variation is closely related to the energy reflection/transmission at joints and voids within the strata.(3) Field measurement results agree with theoretical simulations,validating the numerical model and the above conclusions.The findings of this study provide a practical reference for controlling the impact of shield tunneling vibrations in composite strata.更多还原