大跨度隧道分部开挖超近距离下穿电力铁塔变形控制技术研究  

Research on Deformation Control Technology of Long Span Tinnel Undercrossing Power Tower with Ultra-Short Distance and Partial Excavation Methods

作　　者：王远 WANG Yuan(China Railway 18th Bureau Group No.1 Engineering Co.,Ltd.,Baoding 072750,China)

机构地区：[1]中铁十八局集团第一工程有限公司,河北保定072750

出　　处：《国防交通工程与技术》2023年第5期45-50,共6页Traffic Engineering and Technology for National Defence

基　　金：中铁十八局集团有限公司科技项目(G20-04)。

摘　　要：大跨度隧道以超近距离分部开挖下穿电力铁塔时不可避免的对铁塔桩基产生扰动影响,依托黑白面将军山隧道工程开展了双侧壁导坑法分部开挖下穿电力铁塔数值模拟研究,分析了不同注浆加固方案下地层变形和铁塔桩基稳定性的演化规律。研究结果表明:当不采取注浆加固措施时,中导洞上断面的开挖后围岩最大累计竖向变形为5.3 mm左右,约占最终累计变形的76.8%,是地层变形发展和桩基扰动的关键阶段,电力铁塔随着断面开挖具有向隧道开挖侧偏转的趋势;当采取径向6 m范围注浆加固时,隧道最大拱顶沉降减小了约54%,铁塔桩身倾斜率由0.14‰降低至0.06‰,桩基左右两侧的差异沉降减小,采取注浆加固措施可以实现围岩及铁塔桩基的稳定性控制。It is inevitable that the excavation of the long-span tunnel in ultra-short distance will inevitably disturb the pile foundation of the power tower.based on the Jiangjunshan Tunnel project,this paper conducted a numerical simulation on the partial excavation of tunnel undercrossing the power tower with the two side-wall pilot tunnel method and analyzed the evolution laws of ground deformation and tower pile foundation stability under different grouting reinforcement schemes.The results indicate that without any grouting reinforcement measures,the maximum cumulative vertical deformation of surrounding rock reaches approximately 5.3 mm,accounting for about 76.8%of the final cumulative deformation,which is a critical stage ground deformation development and pile foundation disturbance.The power tower tends to deflect towards the tunnel excavation side.Through adopting grouting within a radial range of 6 m,the maximum settlement is reduced by about 54%,the inclination rate of the iron tower pile body is reduced from 0.14‰to 0.06‰,as well as mitigate the differential settlement of the left and right sides of the pile foundation.Grouting reinforcement measures control the stability of surrounding rock and iron tower pile foundation effectively.

关 键 词：山岭隧道 下穿构筑物 双侧壁导坑法 变形防控 沉降 横向位移 

分 类 号：U455.41[建筑科学—桥梁与隧道工程]