摘要
盾构下穿既有隧道会引发既有隧道产生沉降,并进一步影响既有隧道的运营安全.以合肥市轨道交通2号线东延下穿既有2号线为工程背景,通过数值模拟研究新建双线隧道小角度下穿既有双线隧道对既有隧道竖向沉降的影响.研究结果表明:为确保既有隧道运营安全,最佳注浆压力为0.2～0.3 MPa;最不利断面既有线的竖向位移最大值为-1.629 mm,水平位移最大值为0.284 mm,最大主应力的最大值为-0.228 MPa,最小主应力的最大值为-2.002 MPa;既有线穿越区间各位置实测值均远小于模拟值,除了第一次穿越外,全线既有隧道沉降呈现穿越处沉降大、非穿越段沉降小趋势,实测值均小于结构安全控制指标值,确保了施工的安全,同时可为相似工程提供参考.
Abstract
Shield tunnels passing through existing tunnels can cause settlement and impact the operational safety of the existing tunnels.This study investigates the impact of a small-angle underpass of an existing double-line tunnel by a newly built double-line tunnel in the east extension of Line 2 of the rail transit in Hefei City using numerical simulation.The research results show that the optimal grouting pressure to en-sure the safe operation of the existing tunnel is 0.2～0.3 MPa.The maximum vertical displacement and hor-izontal displacement of the most unfavorable cross-section of the existing line are-1.629 mm and 0.284 mm,respectively.The maximum value of the maximum principal stress is-0.228 MPa,and the max-imum value of the minimum principal stress is-2.002 MPa.The measured values at various positions in the crossing section of the existing tunnel are much smaller than the simulated values.The settlement of the existing tunnel along the whole line shows the trend of large settlement at the crossing and small set-tlement in the non-crossing section,and the measured values are all smaller than the safety control index value of the structure,ensuring the safety of the construction and providing reference for the other similar projects.
基金项目
安徽省住房城乡建设科学技术计划(2022-YF024)
安徽省自然科学基金资助项目(2208085ME149)
NETL
NSTL
万方数据