盾构法施工近距离下穿既有隧道变形影响分析
Analysis of Deformation Influence of Shield Tunnels Passing Through Existing Tunnels at Close Range
秦欣 1王江锋1
作者信息
- 1. 华北水利水电大学,河南 郑州 450046
- 折叠
摘要
为了解盾构法施工近距离下穿对既有隧道影响,依托于实际工程,通过midas GTS NX三维有限元软件仿真模拟新建隧道穿越既有隧道的施工过程,分析既有隧道和土层的变形规律、采用"上小下大"的注浆模式研究注浆压力以及管片环宽对地层变形的影响.研究结果表明:当盾构机开挖掌子面不断靠近既有隧道时,施工对既有隧道的影响不断增大,在下穿时影响最大,此区间的隧道沉降值最大,是穿越过程中最危险的地方,在背离后隧道沉降值逐渐减小;地层随注浆压力的增大,施工造成的周围地层变形减少,在地层沉降没有稳定之前,根据地面的沉降情况,可进行二次注浆;环宽设置值的过大或过小都会增大地表沉降值,选取管片环宽时,要综合具体工程条件、施工成本和施工技术等方面考虑.盾构法施工下穿时,上下重叠区间内既有隧道的变形量最大,需提前做出安全施工的预案,确保施工安全.
Abstract
In order to understand the impact of shield penetration on existing on the actual project,the construction process of the new tunnel crossing the existing tunnel is simulated by midas GTS NX 3D finite element software,the deformation law of the existing tunnel and soil layer is analyzed,and the grouting pressure and segment ring width are analyzed on the formation deformation of the formation by using the grouting mode of"small up and down large".The results indicate that when the shield excavation face is constantly approaching the existing tunnel,the impact of con-struction on the existing tunnel is increasing,and the impact is the greatest when it is underpassed,and the tunnel set-tlement value in this section is the largest,which is the most dangerous place in the crossing process,and it is gradual-ly balanced after divergence.The grouting pressure increases,the deformation of the surrounding formation caused by construction is reduced,and before the formation settlement is not stable,secondary grouting can be carried out ac-cording to the settlement of the ground.Too large or too small setting value of the ring will increase the surface settle-ment value,and when selecting the segment ring width,it is necessary to consider the specific engineering conditions,construction costs and construction technology.
关键词
近距离下穿/既有隧道/变形影响分析/数值模拟/加固措施Key words
close-range underwear/existing tunnels/deformation influence analysis/numerical simulation/re-inforcement measures引用本文复制引用
出版年
2024
NETL
NSTL
维普
万方数据