四线叠交隧道盾构施工地基变形及控制研究

随着轨道交通的不断发展,越来越多的城市地铁线路互相重叠穿越,如何预测并控制隧道所在地层的变形显得尤为重要。本文依托南宁地铁1、2号线在朝阳广场站形成的四线叠交隧道工程,旨在探讨四线叠交这种复杂空间关系下隧道盾构施工的变形规律,进而提出有效措施控制地基变形。基于对水文地质情况及隧道情况的研究,借鉴成都、武汉等地工程情况,提出采用上下洞夹层土体洞内加固、结构加强、螺栓加强以及下洞临时支撑相结合的加固措施来控制地基变形,通过数值模拟验算加固效果,并与现场监测数据作对比,结果表明,加固后地层沉降显著减小,地表沉降满足变形控制要求,隧道变形大大减小。本文的研究成果保证了该重叠段隧道施工的安全,也能为今后类似工程的施工和设计提供借鉴与指导作用。

Study on the Deformation and Control of Foundation in Shield Construction of Four-line Overlapped Tunnel

With the continuous development of rail transit, more and more subway lines go across each other. It is particularly important to predict and control the ground deformation in complex working conditions. This paper relies on the four-line overlapping tunnel project in Chaoyang square station which is formed by Nanning subway line 1 and line 2 to discuss the deformation law of tunnel shield construction under the complex spatial relation of four-line overlapping and intersection, and then puts forward effective measures to control the foundation deformation. Based on the research of engineering hydrogeology and tunnel conditions of the project, drawing lessons from other similar projects in Chengdu, Wuhan and so on, the paper put forward the measures to control the deformation of foundation by strengthening soil between upper and lower hole, strengthening structure, strengthening bolts and setting temporary support of the lower hole. Then the paper verifies the reinforcement effect by numerical simulation, compared with on-site data monitoring at the same time. The results show that the ground settlement decreases significantly after the reinforcement, the surface settlement meets the requirement of deformation control. And the deformation of tunnel also decreases greatly. The research results guarantee the safety of the tunnel construction of the overlapped tunnel and provide guidance for the construction and design of similar projects in the future.