盾构井环框梁等效侧向刚度计算及对基坑的影响分析

为研究在地铁明挖基坑计算中由于忽略盾构井开孔导致的结构侧向刚度削弱问题对基坑受力和变形的影响，以武汉地铁11号线未来三路站标准2层盾构井基坑为例，建立荷载-结构模型，根据k=F/l计算盾构井环框梁结构等效侧向刚度，并将其作为基坑逆工况换撑刚度； 利用Plaxis有限元软件，建立土层-结构模型，对在基坑逆工况回筑过程中采用环框梁等效侧向刚度和整板刚度2种不同换撑的刚度进行对比分析，结果显示： 2种换撑刚度造成围护结构最大位移相差4.8%，最大弯矩相差2.7%，最大剪力相差1.3%，总体差别不大。

Calculation of Equivalent Lateral Stiffness of Shield Shaft Ring Frame Beam and Its Influence on Foundation Pit

The study on the influence of structural lateral stiffness reduction induced by ignorance of shield shaft opening in calculation of open cut metro foundation pit on the stress and deformation of the foundation pit is of great significance. A load structure model for the standard two layer shield shaft foundation pit of Weilaisanlu Station of Wuhan Metro Line 11 is established, and the equivalent lateral stiffness of the shield shaft ring frame beam structure is calculated by the formula of k=F/l, which is used as the foundation pit reverse support condition. And then the soil structure model is established based on finite element software Plaxis, and the comparison is made between the equivalent lateral stiffness of the ring frame beam and the whole plate stiffness in the reverse construction of the foundation pit. The results show that the maximum displacement difference of the retaining structure between the two kinds of stiffness is 4.8%, the maximum bending moment difference is 2.7%, and the maximum shearing force difference is 1.3%, which are small differences.