大断面跨海盾构隧道结构设计与参数分析

为获得精细、合理化的大断面盾构隧道结构设计方法,文章依托某大断面跨海隧道工程,对其结构选型和结构参数进行了分析。从管片拼装方式与分块、管片连接方式、管片材料等方面,分析了管片结构的选型方法;从计算模型的选取、计算工况与荷载的确定、参数的选取、计算结果等方面,分析讨论了管片横断面和隧道纵向结构的数值模拟计算方法及其适用性。结果表明:采用梁-弹簧模型、均质圆环模型计算管片横断面时所得的内力分布并不相同,在实际设计中应以前者计算结果为主,后者进行复核;在地基变化剧烈处,盾构隧道易出现较大的纵向弯矩和管片环间剪力,可通过采用设置变形缝、硬岩破碎等方式予以处理。

Structure Design and Parameter Analysis of a Large-section Sea-crossing Shield Tunnel

In order to obtain a refined and rational structural design method of large-section shield tunnel,the structure selection and structure parameters are analyzed based on a large-section sea-crossing shield tunnel.The selection method of segment structure is analyzed in terms of segment erection method and segmentation,segment connection method and segment material;the numerical simulation calculation methods of segment cross-section and tunnel longitudinal structure and its applicability are analyzed in terms of selection of calculation model,deter mination of calculation conditions and loads,selection of parameters and calculation results.The results show that the internal force distributions in the calculation of segment cross-section by the beam-spring model or homoge neous ring model are not the same,the design should consider the main calculation result while the latter should be used for recheck in actual design;it is easy to produce large longitudinal bending moment and shear between seg ment rings of the shield tunnel located in the place where the foundation changes violently,and it can be solve by setting deformation joints,crushing hard rock block and so on.