近距离垂直交叠地铁盾构隧道的动力响应分析

Dynamic response analysis of short-distance vertical overlapping subway shield tunnels

以郑州地区某地铁隧道段为工程背景,采用三维精细化管片和正交各向异性圆环衬砌模型模拟隧道结构,将地铁列车运行荷载简化为人工激励函数,构建地铁列车运行对相邻近距离垂直交叠隧道动力响应的数值模型,对不同列车位置、隧道结构、列车速度、隧道净距等工况下近距离垂直交叠相邻隧道的竖向振动响应、影响范围和动应力进行分析。研究结果表明:上隧道运行列车对下部近距离隧道的拱顶的振动影响较大,其他区域影响较小;下隧道运行列车对上部近距离隧道的振动影响整体较小;采用错缝拼装有利于降低近距离垂直交叠隧道在交叠段的振动影响;上隧道列车在启动加速阶段和达到最高速度行驶两个阶段对下隧道拱顶的加速度影响较大;随着隧道净距的减小,上隧道列车引起近距离交叠垂直隧道的下隧道的拱顶竖向加速度显著增加,交叠区域的整体振动最强烈,当远离交叠段1倍洞径后,净距对加速度值的影响可忽略不计。

In this study,considering one subway tunnel section in the Zhengzhou area as the research object,the tunnel structure was simulated with the three-dimensional fine segment,and orthotropic circular lining models were employed for the simulation of the tunnel structure,and the operation load of the metro train was simplified as the artificial excitation function.Afterward,the dynamic response of short-distance vertical overlapping tunnels during metro train operation was analyzed by the generated numerical model.The vertical vibration response,influence range,and dynamic stress of adjacent overlapping tunnels in terms of different factors(train position,tunnel structure,train speed,and tunnel clearance distance)were examined.The results revealed the remarkable impact of the running train in the upper tunnel on the vibration of the arch of the lower tunnel,the small impact of the running train in the lower tunnel on the vibration of the upper close tunnel,but a relatively small impact on other areas.The use of staggered assembly can reduce the vibration impact of short-distance vertical overlapping tunnels in the overlapping section.The train running in the upper tunnel has a large impact on the acceleration of the arch of the lower tunnel during the two stages of starting acceleration and reaching the maximum speed.With the decreasing net distance of the tunnel,there is a substantial increase in the vertical acceleration of the arch of the lower tunnel caused by the train on the upper tunnel,as well as the strongest overall vibration in the overlapping area.When the distance from the overlapping section is one time of the tunnel diameter,the influence of the net distance on the acceleration value can be neglected.