砂卵石地层盾构侧穿高架桥桩基的施工控制技术

为探究盾构近接侧穿既有高架桥桩基时各相关施工控制技术的适应性,以成都地铁5号线科园站—高升桥站区间盾构侧穿二环路高架桥为工程背景,提出钢管隔离桩、袖阀管注浆加固、洞内注浆加固、综合加固4种施工控制技术。通过数值模拟,结合现场监测分析,得到结论如下:盾构侧穿高架桩基时双洞间的桩基础位置为施工的高风险区域,局部的施工保护措施可有效阻隔隧道-围岩-桩基-地表的变形传递,出现左右线高低双驼峰现象;由于隧道-围岩-桩基之间的变形传递和互相协调,靠近隧道的桩身均出现局部位移偏移,综合加固技术对控制桩基侧向位移具有良好效果;局部的保护措施对盾构衬砌局部的变形具有显著的改善作用。

Construction Control Technology of Shield Side Crossing Viaduct Pile Foundation in Sandy Cobble Stratum

In order to explore the adaptability of relevant construction control technologies when the shield machine passes on the side through the existing viaduct pile foundation,by taking the section of Keyuan Station—Gaoshengqiao Station on Chengdu Metro Line 5 as the engineering background,where the shield crosses the 2nd Ring Viaduct,four construction control technologies are proposed,including steel pipe isolation pile,sleeve valve pipe grouting reinforcement,grouting reinforcement in tunnel and comprehensive reinforcement scheme.Through numerical simulation,and combined with field monitoring and analysis,it is concluded that the pile foundation position between two holes where the shield crosses the viaduct pile foundation is a high-risk area,and the local construction protection measures can effectively block the tunnel—surrounding rock—pile foundation—surface deformation transfer,resulting in double hump phenomenon of the left and the right lines.Due to the tunnel—surrounding rock—pile foundation deformation transfer and mutual coordination,local displacements will occur on the pile bodies near the tunnel,but the comprehensive reinforcement technology can control effectively the lateral displacement of pile foundation,and local protection measures can significantly improve the local deformation of shield lining.