砂卵石地层大直径盾构始发下穿管线群施工技术——以成都轨道交通17号线温明区间盾构工程为例

Construction Technology of Large-Diameter Shield Launching underneath Pipeline Group in Sandy-Cobble Strata:a Case Study of Shield Tunnel of Wenquan Avnue Station-Mingguang Station Section on Chengdu Metro Line 17

为解决砂卵石地层大直径盾构始发下穿高压燃气管线群的沉降控制技术难题,以成都轨道交通17号线一期工程TJ06标温泉大道站—明光站区间盾构隧道工程为依托,采用方案论证及现场实测等手段,对地铁大直径盾构始发下穿管线群加固方案、施工工艺及控制参数等开展研究。结果表明:1)采用双层大管棚、袖阀管注浆及井点降水组合方案可有效控制砂卵石地层盾构始发地表沉降;2)采用条形基础加固+钢丝悬吊固定的保护措施可有效控制砂卵地层管线沉降;3)在相同地质条件及埋深地段盾构掘进试验基础上,提出砂卵石地层始发穿越管线时盾构掘进两阶段控制参数建议值;4)管线沉降监测数据表明,盾构施工过程中管线累计沉降小于控制标准。

The settlement control is of great significance in large-diameter shield launching underneath high-pressure gas pipeline group in sandy-cobble strata.Hence,researches are conducted on reinforcement scheme,construction technology and parameters control of a large-diameter shield launching underneath pipeline group at Wenquan Avnue station-Mingguang station section on Chengdu metro line 17 using program demonstration and on-site measurement methods.The results show the following.(1)The surface settlement induced by the shield launching in sandy-cobble strata can be effectively controlled using combination scheme of double-layer large pipe roof,Soletanche grouting and well point dewatering.(2)The settlement of pipeline in sandy-cobble strata can be effectively controlled by adopting the protection measures of strip foundation reinforcement and steel wire suspension fixation.(3)The recommended two-stage control parameters for shield launching underneath pipeline in sandy-cobble strata are proposed based on the excavation test of shield tunnel in the same geological conditions and buried depth.(4)The pipeline settlement monitoring data show that the cumulative settlement of the pipeline during shield tunneling is within the control standard.