软土地层盾构近距离下穿隧道无沉降施工技术

Construction Technology of Soft Soil Layer Shield Underpass Tunneling Without Settlement in Short Distance

在盾构近距离下穿既有地铁线工程中,既有地铁隧道和道床会产生即时沉降和滞后沉降,最终造成沉降超标。本文在充分研究工程地质与水文条件的基础上,通过理论计算即时沉降值,通过试验段分析滞后沉降值,设计科学合理的全面控制隆沉施工方案。在穿越过程中通过信息化监测数据及时调整盾构掘进参数,按计算沉降值预留隆起量,通过一系列的注浆措施维持隆起量来抵消滞后固结沉降,最终达到"无沉降"的目标,无须后期补偿注浆。

In the existing subway line project,the existing subway tunnel and track bed will produce immediate settlement and lag settlement and it will eventually cause the settlement to exceed the standard.On the basis of fully studying the engineering geological and hydrological conditions,the real-time settlement value is calculated theoretically,and the delayed settlement value is analyzed through the test section,and a scientific and reasonable construction scheme for controlling the uplift is designed.In the process of crossing,the shield tunneling parameters are adjusted in time by information monitoring data.The uplift amount is reserved according to the calculated settlement value,and the uplift amount is maintained by a series of grouting measures to offset the delayed consolidation settlement,and finally achieve the goal of"no settlement"without the need of later compensation grouting.