超大直径盾构下穿棚户区沉降控制技术研究

Research on Settlement Control Technology of Oversized Shield Tunneling Through Sheds Area

超大直径盾构下穿老旧棚户区微扰动施工控制是地下工程实践中面临的重要难题。本文以武汉地铁8号线黄浦路站—徐家棚站区间盾构下穿棚户区项目为工程背景,首先对提出全断面粉细砂层注浆加固工艺并进行浆液配比实验给出最佳浆液配比,并对盾构施工过程进行实时监测监控,根据工程具体情况对盾构机下穿掘进参数进行分析,最后提出超大直径泥水盾构穿越棚户区施工的控制措施。研究结果表明:袖阀管注浆加固工艺对超大直径盾构下穿的老旧棚户区具有较好的保护作用,现场试验确定最佳水灰配比为0.8∶1;盾构穿越过程中地表沉降纵向变化呈近似U型分布,横向变形出现明显沉降槽,加固棚户区老旧结构基础最大隆起值为15 mm,建筑结构整体先隆起后减弱,且沉降值控制在15 mm以内;盾构机总推力和刀盘扭矩、盾构机总推力和土舱压力、出土率和土舱压力具有变化规律一致性。研究结果为揭示超大直径盾构下穿老旧棚户区施工过程对地层和地面建筑结构的影响规律提供参考和依据。

The construction of control of micro-disturbance by using ultra-large diameter shields under old shanty towns is a difficult problem in underground geotechnical engineering practice.This article takes the project of shield tunnelling through the shantytown area of the Huangpu Road Station to Xujiachang Station on Line 8 of the Wuhan Metro as the engineering background.First,it proposes the best method for grouting reinforcement of the full-surface fine sand layer and conducts slurry proportioning experiments.Slurry ratio,and monitoring and monitoring of the shield construction process in real time,according to the specific conditions of the tunnel machine under the shield tunneling parameters analysis,and finally proposed a large diameter slurry shield through the shantytown construction control measures.The results of this study show that the sleeve grouting technique has good protection for the old shanty towns worn by oversize shields,and the field test determines that the optimum ratio of water to cement is 0.8∶1;during the process of shield tunneling The vertical settlement of the ground settlement showed an approximate U-shaped distribution.There was a clear settlement trough in the lateral deformation,and the maximum uplift value of the old structure foundation in the reinforced squatter settlement was 15 mm.The entire building structure first ascended and then weakened,and the settlement value was controlled within 15 mm;the total shield machine The thrust and the torque of the cutterhead,the total thrust of the shield machine,the pressure of the chamber,the rate of excavation and the pressure of the chamber are consistent with each other.The research results provide reference and basis for revealing the influence of the construction process of oversized shields on the stratum and ground construction structure under the old shantytown construction process.