矿山法扩挖盾构隧道断面的关键技术

因周边环境复杂,郑州市轨道交通1,2号线联络线与正线分岔区隧道施工难度很大。本文首先提出矿山法扩挖盾构隧道形成大断面隧道的施工方案,阐述了其关键技术,然后对扩挖过程进行了数值模拟分析。结果表明:在洞内径向注浆、超前管棚支护、管井降水等辅助措施下采用矿山法开挖可将成型盾构隧道扩挖成大断面隧道;扩挖中采用型钢连接措施进行新旧结构受力体系转换,可防止土体失稳,有效控制地表沉降,加快工期。本文介绍的方法为地铁分岔区隧道的建设提供了一种新思路。

Key Technology of Enlarging Shield Tunnel Cross-section by Mining Method

Due to the complex surrounding environment,it is very diff icult to construct the bifurcation area tunnel between the connecting line and the main line of Zhengzhou rail transit line 1 and line 2. Firstly,this paper put forw ard the construction scheme of shield tunnel enlarging excavation by mining method to form large cross-section tunnel,discussed its key technology,and then carried out numerical simulation analysis of the enlarging excavation process.The results show that under the auxiliary measures of radial grouting in the tunnel,advanced pipe roof support and pipe well dew atering,the shaping shield tunnel can be expanded into a large cross-section tunnel by mining method,the stress system transformation between new and old structures by means of section steel connection measures can prevent soil instability,effectively control surface settlement and accelerate construction period in the course of enlarging excavation. The method introduced in this paper provides a new idea for the construction of bifurcation area tunnel in the metro.