列车动荷载影响下深基坑支护结构变形及隔离桩隔振效果研究

随着城市轨道交通迅速发展,深基坑工程在已运营地铁旁施工已较为常见。为研究列车动荷载作用下深基坑支护结构变形规律以及评价隔离桩的隔振效果,以武汉市华中科创产业园超大深基坑工程为背景,采用激振力函数模拟计算列车动荷载,通过FLAC3D有限差分软件模拟分析列车动荷载以及隔离桩对深基坑支护结构变形的影响,并将现场监测数据与数值结果对比分析,验证数值模拟方法的可靠性。研究结果表明：激振力函数模拟列车动荷载输入数值模型得到的基坑支护结构变形规律与现场实测基本一致；列车动荷载对基坑支护结构变形影响较小,列车动荷载作用下地表沉降和围护桩变形各增加了1.3mm、3.6mm；隔离桩对列车动荷载具有较好的隔振作用,使地表沉降和围护桩变形分别减小了28%、6.8%。研究成果具有一定的实际推广价值,能为类似工程提供参考。

Study on deformation of deep foundation pit supporting structure and vibration isolation effect of isolation pile under the influence of train dynamic load

With the rapid development of urban rail transit, the construction of deep foundation pit beside the existing metro is more common. In order to study the deformation law of supporting structure of deep foundation pit under the action of train dynamic load and evaluate the vibration isolation effect of isolation pile, taking the super deep foundation pit project of Wuhan Huazhong Science and Technology Innovation Industrial Park as the background, the dynamic load of train was simulated and calculated by using the excitation force function, and the influence of train dynamic load and isolation pile on the deformation of deep foundation pit supporting structure was simulated by FLAC3D finite difference software The reliability of the numerical simulation method is verified by comparing the monitoring data with the numerical results. The results show that: the deformation law of foundation pit support structure obtained by the numerical model of excitation force function simulating train dynamic load input is basically consistent with the field measurement; the influence of train dynamic load on the deformation of foundation pit supporting structure is small, and the ground settlement and retaining pile deformation under train dynamic load increase by 1.3mm and 3.6mm respectively; isolation pile has good vibration isolation effect on train dynamic load, which makes the ground surface more stable The settlement and deformation of retaining piles are reduced by 28% and 6.8% respectively. The research results have a certain practical promotion value and can provide reference for similar projects.