地铁近距离下穿运营国铁扩底桩基础站房技术研究

Study on Technology of Metro Undercrossing Belled Piles Foundation National Operating Railway Station in Short Distance

为研究地铁近距离下穿运营国铁扩底桩基础站房加固措施,本文以太原某地铁盾构区间与站房成约90°夹角、竖向近距仅为4.0m、从正中央下穿为工程背景,采用理论分析、三维数值分析相结合的方法,模拟盾构左右线先后下穿站房的施工过程,对盾构隧道下穿既有站房变形趋势及变形量进行预测。针对盾构下穿站房预加固措施实施局限性大、对车站运营组织影响大等特点,给出适宜的加固措施;并对加固措施进行理论分析,结果表明,在不采取站房加固措施的情况下桩基础最大沉降5.5mm,采取加固措施后桩基础的最大沉降降低至3.3mm,计算结果表明了加固措施在抗变形、提高桩基础站房整体性上具有较好的效果。

In order to study the reinforcement measures of metro undercrossing belled piles foundation national operating railway station in short distance,this paper takes a metro shield interval in Taiyuan as an engineering background,which is at an included angle of about 90°to the station house,with a vertical short distance of only 4.0 m,and undercrossing the center,and adopts a combination of theoretical analysis and three-dimensional numerical analysis to simulate the construction process of the shield left and right lines successively undercrossing the station house,and predict the deformation trend and deformation amount of the shield tunnel undercrossing the existing station house.Aiming at the characteristics of the shield tunnel undercrossing the station house,such as large limitations of implementing the pre-reinforcement measures and great impact on the station operation organization,suitable reinforcement measures are given;and theoretical analysis of the reinforcement measures is carried out.The results show that,the maximum settlement of the pile foundation is 5.5 mm in the case of no reinforcement measures for the station house,and after adopting the reinforcement measures,the maximum settlement of the pile foundation is reduced to 3.3 mm.The computation results show that the reinforcement measures have good effects in the deformation resistance and improving the integrity of the pile foundation station house.