富水砂卵石地层盾构隧道近接下穿运营线路变形特性分析

Analysis of Deformation Characteristics of Undercrossing Line in Operation Adjacent to Shield Tunnel in Water-rich Sandy Cobble Stratum

依托成都地铁19号线双流机场—龙桥路站区间下穿既有运营地铁3号线工程,采用ANSYS数值模拟软件,分析富水砂卵石地层超前管棚支护和洞内深孔注浆联合加固下,盾构穿越施工全过程的地表沉降和既有地铁管片支护结构变形规律,并通过实测数据验证数值模拟的准确性。结果表明:地表竖向沉降符合Peck曲线分布,地表最大沉降2.59 mm,满足下穿施工控制要求;3号线管片保持平稳,竖向位移最大值4.80 mm,左右拱腰虽然在穿越段受开挖扰动,发生较大水平位移,但在穿越后基本恢复;现场实测数据表明联合加固方案可确保盾构施工及运营线路的安全。

Based on the engineering of Shuangliu Airport-Longqiao Road Station section of Chengdu Metro Line 19 undercrossing the existing Metro Line 3,ANSYS numerical simulation software was used to analyze,under the reinforcement combined advance pipe-shed support with deep hole grouting inside the tunnel in water-rich sandy cobble stratum,the settlement feature of ground surface and the deformation feature of segment support structure for existing subway in the whole course of shield undercrossing;and then on the basis of the measured data,the numerical simulation was proved to be correct.The result shows that,the vertical settlement of ground surface conforms to Peck curve distribution,and the maximum subsidence is 2.59 mm and meets the control requirement of underpass construction;the segments of Line 3 keep stable and the maximum vertical displacement is 4.80 mm;the left and right hance are subject to excavation disturbance in the undercrossing section,leading to relatively large horizontal displacement,but it will nearly recover after the underpass construction.The data measured on the site indicate that the combined reinforcement scheme may ensure the safety of shield construction and the line in operation.