灌注桩施工对运营盾构隧道影响研究  

Study on the Influence of Cast-in-place Pile Construction on Operation of Shield Tunnel

作　　者：高永 李济民 GAO Yong;LI Jimin(Nanjing Metro Operation Co.,Ltd.,Nanjing 210012,China)

机构地区：[1]南京地铁运营有限责任公司,南京210012

出　　处：《现代交通技术》2022年第1期59-63,74,共6页Modern Transportation Technology

摘　　要：以南京长江漫滩地层某道路暗桥全套管钢护筒灌注桩近接既有盾构隧道施工为工程背景,通过单桩及群桩施工期间既有盾构隧道变形现场的实测结果分析及回归分析表明:单桩施工工况下,全钢护筒施工方案相比半钢护筒施工方案,临近既有盾构隧道变形主要发生在钢护筒穿越密实砂层期间,5~15 m净距工况下,变形总量增加2.6~4.3倍,影响半径扩大30%;群桩施工工况下,通过调整群桩成桩顺序实现遮挡隔离作用,可有效减少后续成桩对运营隧道的影响,隧道变形量平均降幅达35%。由此说明,穿越密实砂层的全钢护筒方案对既有盾构隧道影响较大,近接运营隧道施工方案须慎重论证,不穿越密实砂层的半钢护筒方案可作为既有盾构隧道结构保护的主动预防措施方案。Taking the construction of a full casing cast-in-place pile for a road covered bridge in the floodplain of the Yangtze River in Nanjing as an engineering case,based on the field test results and regression analysis of the deformation of the existing shield tunnel during the construction of single pile and group piles,it is shown that under the construction of single pile,the construction scheme of all steel casing is better than that of half steel casing,the deformation of the existing shield tunnel mainly occurs when the steel shield tube passes through the dense sand layer,and the total deformation increases 2.6~4.3times when the net distance between the steel shield tube and the sand layer is 5~15 m,and the influence radius is enlarged by 30%when the steel shield tube is driven through the dense sand layer.By adjusting the sequence of pile groups to achieve shielding and isolation,the influence of subsequent pile groups on the operation of tunnels can be effectively reduced,and the average deformation of tunnels can be reduced by 35%.Therefore,it can be seen that the all-steel casing scheme passing through the dense sand layer has a great influence on the existing shield tunnel,and close to the operation of the tunnel construction needs careful demonstration,the semi-steel shell without passing through the dense sand layer can be used as an active preventive measure for the protection of existing shield tunnel structures.

关 键 词：全套管灌注桩 钢护筒 盾构隧道 现场实测 回归分析 

分 类 号：U459.3[建筑科学—桥梁与隧道工程]