盾构在富水粉细砂层中长距离平行下穿有压敏感管线施工控制技术

Construction Control Technologies for Shield Tunnel Boring in Water-rich Fine Silty Sand Strata and Parallel Crossing Underneath Pressured Water-supply Pipeline

郑州地铁2号线国基路站—北环路站区间隧道在富水粉细砂地层中长距离下穿3条有压给水管线,给水管为混凝土管材,稳定性较差。为满足设计单位和产权单位对施工沉降的要求,分析盾构隧道下穿施工过程中,不均匀沉降导致地层土体变形的施工风险,地层沉降主要受刀盘结构形式、刀盘支撑形式(影响渣土改良效果)、渣土改良剂在刀盘上的注入位置3方面影响。从设备选择及改造、施工工艺措施方面予以优化:1)盾构刀盘结构形式及相应配置要适应富水粉细砂层掘进和保压;2)合理的施工参数及工艺措施对地表沉降控制的必要性。监测结果表明,管线最大沉降满足风险源控制目标。

The Guojilu Station-North Huanchenglu Station shield bored tunnel on Zhengzhou Metro Line No. 2 is located in water-rich fine silty sand strata and crosses underneath 3 existing pressured water-supply concrete pipelines. In order to meet the settlement control requirements,the construction risk of soil deformation induced by heterogeneous settlement is analyzed. The cutterhead structure type,cutterhead support type and injection points of ground conditioning agent on cutterhead are the main factors for ground settlement. Some suggestions are propased as follows： 1） The shield cutterhead structure type and related devices are very important. 2） Rational construction parameters and technologies are necessary. The monitoring results show that the maximum pipeline settlement can meet the risk control requirement.