盾构隧洞复合衬砌的荷载结构共同作用模型

Modeling load-structure interaction in shield tunnel composite lining

盾构隧洞复合衬砌用于承受高内水压力是一种正在被应用的新型结构,计算这种结构的受力目前还缺乏有效的实用方法。文章采用荷载结构法,分别计算围岩、各层衬砌结构单独承担内水压力时径向位移与内水压力关系,然后根据围岩和各层衬砌径向位移变形协调条件确定复合衬砌各自分担的内水压力。各构件分别承担的内水压力之和即为复合衬砌承担的内水压力,再叠加上隧洞外围岩水土压力所能平衡的内水压力,即为总的能承担的内水压力。用这种方法初步分析了已建的工程和与有限元方法的结果进行了比较,结果较为一致。该方法力学概念明确,计算简便,可为分析这种结构提供一种简便实用的计算方法。

Shield tunnel composite lining under high internal water pressure is a new structure coming into use, while effective practical methods for its force calculation are still lacking. In this paper, a loadstructure method is used to calculate the surrounding rock and lining layers separately-for each layer, first obtaining the relationship of its radial displacement versus the internal water pressure, and then determining the load according to the displacement compatibility. The bearing capacity of the composite lining can be defined as the internal water pressure assumed by each component, plus the internal water pressure that can be balanced by the water and soil pressure outside the tunnel. This method is applied to a preliminary analysis of existing tunnels and achieves good agreements with FEM simulations. It is based on the clear concepts of mechanics and easy to apply, thus providing a practical method for analysis of shield tunnel lining.