采用深基坑法对盾构机纠偏综合施工技术

在盾构法隧道施工中,若盾构机偏离设计轴线较大,自身无法拟合至线路轴线,况且亦无法通过调线方式补救时,可以采取开挖深基坑的方法尝试纠偏。一般基坑开挖均在没有或仅有小型障碍物的情况下进行,盾构机存在的环境下深基坑开挖较为少见。结合某工程实例,针对盾构机存在的特殊性,在常规基坑开挖的基础上,大胆采用了盾体支撑技术,先撑后挖,同时辅以桩外土体加固措施,克服了地质条件差、地下水丰富、周边环境复杂、基坑形状不规则、施工难度大等不利因素,顺利完成了基坑封底,成功实现盾构纠偏,使深基坑法对盾构纠偏成为可能。

Integrated Construction Technology of Adopting Deep Excavation Method in Shield Correction

In tunnel construction with the shield method,with a big deviation from the designed axis,the shield can not fit into the axis by itself.In addition,when the axis cant be adjusted for remedy at the time,the method of deep excavation can be adopted for correction.Common foundation excavation is carried out when there is no or a few tiny barriers,and a deep excavation with the existence of shield is rarely seen.Combined with engineering practice,and in light of the specialty of the shield,based on conventional foundation excavation,the technology of shield body support is adopted.As there are support before excavation and the measure of soil consolidation out of piles,many adverse factors are overcome,including the poor geological condition,rich ground water,complicated surrounding environment,irregular foundation pits and difficult construction.Finally,sealing of the foundation pit is accomplished with the correction of shield,which makes shield correction with the deep excavation method possible.