管幕结构法侧穿车站雨棚桩基影响分析

Numerical Analysis Influence of Metro Tunnel Excavation by Perorated Pipe Grouting Method on the Adjacent Pile Supported Canopy Station Structure

太原市迎泽大街下穿火车站通道工程采用管幕结构法施工,具有大跨度、超浅埋、严格控制沉降等特征。采用数值计算对钢管顶进、钢管切割及混凝土浇筑、土方开挖等主要工序下车站雨棚桩基沉降变化规律进行了研究,并制定了雨棚桩基允许沉降控制标准。结果表明:1)管幕结构法施工时,对侧穿的雨棚基础产生了一定的影响,雨棚基础发生了水平和竖向位移;2)雨棚基础的水平位移主要发生在钢管顶进和管幕切割阶段,土方开挖施工对雨棚基础影响较小;3)施工完成后,雨棚基础最大水平位移为1.18 mm,最大竖向位移为4.59 mm,满足沉降控制标准相关要求。

The Yingze Underpass Tunnel in Taiyuan City was excavated by using perforated pipe jacking and grouting method.It had the characteristics of large span,shallow embedment depth and restrictive settlement control.The construction process such as,steel pipe jacking,cutting,concrete pouring and earthwork excavation,were numerically simulated.The settlement of the adjacent pile supported canopy station induced by the tunnel excavation was also evaluated.The allowable settlement value for the canopy structure was recommended.The following conclusions can be obtained:1)during the tunnel excavation using perorated pipe jacking and grouting method,the adjacent pile supported canopy station structure was adversely affected since both vertical and horizontal deflections were observed.2)The horizontal deflections at the canopy structure were mainly occurred during the pipe jacking and cutting stages.The earthwork stage had a relatively small impact on the horizontal deflection of the canopy structure.3)After the construction,the maximum horizontal deflection at the canopy foundation level was 1.18 mm and the maximum vertical settlement was 4.59 mm and both values met the allowable settlement requirements.