新建轨道线区间隧道下穿既有线路变形影响分析

ANALYSIS ON THE INFLUENCE OF THE DEFORMATION OF THE NEWLY-BUILT TRACK TUNNEL UNDERNEATH THE EXISTING LINE

以武汉新建轨道交通12号线盾构区间下穿既有2号线长~汉盾构区间为工程背景,采用三维数值模拟分析新建线路施工对既有轨道交通变形的影响。研究结果表明:盾构掘进施工对既有结构及线路影响较小,盾构隧道贯通后区间结构最大竖向位移为–4.96 mm,最大水平位移为0.309 mm,2号线盾构区间累计最大沉降量为–2.86 mm,区间结构变形量和沉降量在相关规范控制范围内,满足区间安全运营要求。通过设计上加强管片配筋、增加注浆孔,隧道施工中加强掘进参数控制和及时同步注浆,加强二次注浆,同时对2号线长港路站—汉口火车站区间设置监测点,指导施工,保证地铁安全运营。

In view of the great influence of the new subway track tunnel under the existing line,taking the shield section of the existing Changgang Road Station to Hankou Railway Station as the engineering background,the influence of the settlement and deformation of the existing rail transit structure is evaluated by three-dimensional numerical simulation.The research results show that the shield tunneling construction has little influence on the existing structure and line.After the shield tunnel is completed,the maximum vertical displacement of the interval structure is-4.96 mm,the maximum horizontal displacement is 0.309 mm,and the cumulative maximum settlement of the shield interval of Line 2 is-28.6 mm.The deformation and settlement of the interval structure are within the control range of the relevant codes,which can meet the requirements of safe operation.Through strengthening the reinforcement of segments and increasing grouting holes in design,strengthening the control of tunneling parameters and timely synchronous grouting in tunnel construction,strengthening secondary grouting,and setting up monitoring points in the section from Changgang Road Station to Hankou Railway Station of Line 2 to guide the construction,ensure the safe operation of the subway.