粉砂地层中列车载荷对曲线隧道沉降的影响

Effect of train load in silt formation on the settlement of curved tunnel

为揭示粉砂土层中列车移动载荷作用下曲线隧道沉降规律,采用MIDAS数值模拟软件,对地铁列车载荷进行动态模拟,以郑州地铁一号线一期工程为背景,对隧道结构进行现场实测,将作用在轨道上的载荷分解成列车轴重引起的竖向力、横向力以及轨道超高引起的离心力,研究列车移动载荷对不同曲线半径和车速条件下隧道周围土层动力响应和沉降的影响.研究结果表明:粉砂土层中列车振动载荷对曲线隧道周围土层的影响主要在隧道底部0~15m内;隧道下方土层动力响应和长期累积沉降随着隧道转弯半径的增加而减小;列车运行速度的提升导致隧道下方土体动力响应增加71.4%,与之对应的长期累积沉降值降低6.4%.研究结论总结了列车载荷对隧道的沉降影响规律,为盾构隧道工程施工提供参考与建议.

In order to reveal the settlement law of the curved tunnel under the moving load of the train in the silty soil layer,MIDAS numerical simulation software was used to dynamically simulate the subway train load.Taking the first phase of the Zhengzhou Metro Line 1 as the background,the tunnel structure was measured on site to decompose the load acting on the track into the vertical caused by the axle load of the train directional force,lateral force and centrifugal force caused by super high track for studying the effect of train moving load on the dynamic response and settlement of the soil layer around the tunnel under different curve radius and speed conditions.The results show that the impact of the train vibration load on the soil layer around the curved tunnel in the silty soil layer is mainly in the range of 0~15 m at the bottom of the tunnel;the dynamic response of the soil layer under the tunnel and the long-term cumulative settlement decrease with the increase of the turning radius of the tunnel;The increase in train speed resulted in a 71.4%increase in the dynamic response of the soil below the tunnel,but the corresponding long-term cumulative settlement value decreased by 6.4%.The research conclusion summarizes the influence of train load on the settlement of the tunnel,and provides reference and suggestions for the construction of shield tunnel engineering.