城市浅埋连拱隧道单洞法施工工序的优化

通过对单洞法中的上下台阶法与交叉中隔壁（CRD）法及其施工顺序的数值模拟，分析了大跨度连拱隧道单洞法施工中的位移控制效果与支护承载情况.结果表明，与上下台阶法相比，CRD法施工对隧道顶部围岩的竖向位移、拱腰的水平位移以及地表沉降的控制效果较好.在CRD法施工过程中，后行洞宜先开挖外侧区域，再开挖内侧区域.

Optimal Analysis of Construction Schemes for Urban Shallow Buried Multi-arch Tunnel by Single-Tunnel Method

Building a large-span multi-arch tunnel by single-tunnel method under complex urban shallow-buried conditions is a challenging engineering problem.Without the middle wall supporting,it is very important to choose a suitable construction method and scheme,which is used to control the deformation of the surrounding rock,and reduce the adverse effect of construction process.By finite element method,the excavation effects of two construction methods,the bench method and the center cross diaphragm(CRD) method,were compared based on the displacements of surrounding rock and lining.The result shows that the CRD method has advantages in coupling the surrounding rock.For the CRD method,it is better to excavate the outer than the inner regions.