Longitudinal rigidity of shield tunnels based on model tests

In order to explore the performances of longitudinal deformation and the efficienct values of bending rigidity of shield tunnels, straight-jointed, stagger-jointed and uniform longitudinal models are investigated based on model tests and similarity theories. The values of longitudinal deformation of three kinds of longitudinal models under loads are measured by a data acquisition system. The rules of longitudinal deformation and the efficiencies of bending rigidity of the straight-jointed stagger-jointed, and uniform longitudinal models under all loading stages are obtained, by adding the concentrated loads on the models. The comparative analysis of the test results shows the linear relationship between the longitudinal deformation and the loads. The range of the efficienct values of longitudinal bending rigidity is between 0.18 and 0.39 under straight-jointed condition, and in the stagger-jointed model it is between 0.20 and 0.40. What's more, the performances of the longitudinal bending of straight-jointed and stagger-jointed tunnels are similar, and the stagger-jointed effect is not obvious to the longitudinal deformation of shield tunnels. This study may provide some references for the design of shield tunneling in China. ©, 2014, Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering. All right reserved.