竖井施工对邻近管线水平位移影响的研究

Research on the Influence of Shaft Construction on the Horizontal Displacement of Adjacent Pipelines

为了研究与竖井邻近的地下管线的水平位移量受竖井施工影响的变化规律,以北京地铁12号线蓟门桥车站竖井的施工为工程背景,利用FLAC3D软件建立竖井—土—管线结构的三维有限差分计算模型,结合现场实测数据,选取了与竖井长度和宽度方向上邻近的不同的管线为研究对象。根据计算结果:对于水平矩形截面的竖井,长边的水平位移量大于短边的水平位移量;沿着平行于竖井宽度方向设置型钢支撑能有效地控制竖井的变形;平行于竖井长边的管线受竖井施工的影响较大,并且受影响的管线的范围约为竖井长度的两倍。研究结果表明,对管线下方的土体进行加固并且提高管线邻近处竖井壁的刚度,能有效地减小与竖井邻近处的地下管线的水平位移。

For investigating the effect of shaft construction on the existing underground adjacent pipelines,including the settlement and horizontal displacement of pipelines,a case of Ji Menqiao station of Beijing Metro Line12 is employed.A fully numerical analysis model coupled shaft-soil-structure was established by FLAC3 D software.Combined with field measurement data,numerical analysis date were used to analyze the deformation characteristics of different pipelines adjacent to the length and width of the shaft.The numerical findings show that the horizontal displacement of the long edge is greater than that of the short edge for the shaft with rectangular cross-section.The horizontal displacement of the shaft can be effectively controlled by setting the steel bracing parallel to the width of the shaft.The pipeline parallel to the long side of the shaft is greatly influenced by the shaft construction.Besides,the scope of the affected pipeline is about twice times the length of the shaft.The numerical results indicate that as for the underground pipelines affected by shaft construction,the soil beneath the pipelines should be strengthened and the stiffness of the shaft wall near the pipelines should be improved.