断面非对称小净距黄土地铁隧道施工顺序模拟对比研究

Comparative Simulation of the Construction Sequence of Asymmetric Small Clear Loess Subway Tunnel

西安地铁5号线兴庆路站至青龙寺站区间隧道在兴庆路站站后设置停车线,为同时满足左线停车和双线正常行车的功能需求,拟选用左线(大断面)双侧壁导坑法和右线(小断面)台阶法的施工方案进行施工。针对该地铁隧道不同施工顺序采用二维动态有限元数值模拟,通过分析施工引起的拱顶沉降、拱腰收敛、地表变形、衬砌内力和中间土体应力特征及规律,得出大小断面地铁隧道先后施工相互影响的规律性成果:不同施工顺序对拱顶沉降和地表变形影响相差不大,而先行小断面隧道采用台阶法施工完成后对隧道拱腰收敛、衬砌内力及中间土体应力的影响较先行大断面施工的影响小,采用先施工小断面隧道的施工顺序更为合理。

The sectionfrom Xingqing Rd Station to Qinglongsi Station on Xi′an metro Line 5 designed a parking lane behind the Xingqing Rd Station,in order to meet the functional requirements of parking on the left and normal driving on double lines.The construction scheme selects the double-side-drift method and bench cut method,in which the left tunnel with large inner section is excavated by double-side-drift method,while the righttunnelwith small inner section is constructed by bench cut method.Because of the different construction sequences of the tunnel,a2 D dynamic finite element numerical simulation method is adopted.By analyzing the regulations of vault settlement,haunch convergence,ground surface deformation,internal force of lining and intermediate soil stressand so on,some regular achievements on the mutual effects of the large and the small section on subway tunnel are obtained.The results indicate that different construction schemes have little influence on vault settlement and surface deformation,but the construction of small section with bench cut methodfirstwill have no affect on tunnel haunch convergence,internal force of lining and intermediate soil stress,so it is a more reasonable to arrange the construction of the small section first.