市政道路下穿对机场快轨U形槽变形的影响分析

市政道路下穿机场快轨U形槽的施工过程中,对机场U形槽的沉降变形控制要求严,工程实施难度及风险大。基于北京次干一路下穿新机场快轨U形槽的工程背景,采用有限元软件对道路下穿机场快轨U形槽过程进行数值模拟,研究既有新机场U形槽结构的变形。提出市政道路下穿机场快轨U形槽的沉降变形控制标准,即U形槽位移+4^-4 mm、变形速率≤1 mm/d。得出U形槽结构的变形规律及安全性:在基坑及隧道开挖过程中,由于基坑的卸载作用对隧道沉降槽的影响,土层的位移产生类似板的翘曲效应,而U形槽及路基刚好位于中心位置,受到的影响较小,且承载力和裂缝宽度值均满足控制要求。

Analysis of the Influence of Underpassing Municipal Road on the Deformation of U-shaped Groove of Airport Express Rail

During the construction process of the municipal road passing under the U-shaped trough of the airport express rail,the control of the settlement deformation of the U-shaped trough of the airport is strict,and the implementation difficulty and risk of the project are enormous.Based on the engineering background of Beijing Ciganyi Road under the new U-shaped trough of the new airport,the finite element software is used to simulate the U-shaped trough of the road under the airport and study the deformation of the U-shaped trough structure of the new airport.The settlement control standard for the municipal road passing under the U-shaped groove of airport express rail is proposed.That is,the U-shaped groove displacement(+4^-4)mm and the deformation rate≤1 mm/d.The deformation law and safety of the U-shaped groove structure are obtained.During the excavation of the foundation pit and the tunnel,the displacement of the soil layer produces a warping effect similar to the plate due to the influence of the tunnel settlement groove of the unloading action of the foundation pit.The U-shaped groove and the subgrade are located exactly at the center position and less impacted,and their bearing capacity and crack width meet the control requirements.