风化花岗岩地层中地铁盾构隧道施工关键技术

Key Technologies of Subway Shield Tunnel Construction in Weathered Granite Stratum

新加坡地铁汤东线T217标段从不同风化程度花岗岩中穿过,且地面上是新加坡外交部和多个国家驻新加坡大使馆,地理环境敏感,对施工要求高。本文从盾构机刀盘和驱动系统、泥水舱压力平衡系统、泥浆输出监控系统、泥水分离系统和辅助设备五个方面介绍了盾构机系统的选型设计。针对不同工况,施工前确定了五组泥浆关键性能指标,用以指导泥浆制备与调整。在全~中等风化花岗岩混合层中掘进时,推进力保持在24~26 MN,刀盘转速在2.6~2.8 r/min;地面最大沉降7 mm,出现在P170环(外交部和舍伍德路公寓之间);地层损失率约1.01%,满足设计要求,对地面建筑物和地下设施基本无影响。

The T127 bid section of Singapore Metro Thomson-East Coast Line passes through granite with different weathering degrees. On the ground are the Ministry of Foreign Affairs of Singapore(MFAS)and Embassies of many countries in Singapore. The geographical environment is sensitive and the construction requirements are high. This paper introduced the selection and design of shield tunneling machine system from five aspects:shield tunneling machine cutterhead and driving system,mud tank pressure balance system,mud output monitoring system,mud water separation system and auxiliary equipment. According to different working conditions,five groups of key performance indexes of mud were determined before construction to guide mud preparation and adjustment. When driving in the fully and moderately weathered granite mixed layer,the propulsive force is maintained at 24 ~ 26 MN and the rotating speed of the cutterhead is 2.6 ~ 2.8 r/min;the maximum ground settlement is 7 mm,which occurs in P170 Ring(between MFAS and Sherwood Road Apartment). The formation loss rate is about 1.01%,which meets the design requirements and has basically no impact on ground buildings and underground facilities.