Influence of segmental joints on tunnel lining

A simplified method for evaluating the moment carrying of a segmental tunnel liner was proposed using a result from a FEM analysis in which parameters were obtained by calibration against a true scale model test. Influence of segmental joint, number of segment and soil subgrade modulus on the bending moment carrying characteristics of a segmental tunnel was examined. Joint was represented by a series of springs called angular joint stiffness. Based on a set of model tests, practical range of angular joint stiffness was in range of 1000–3000 kN m/rad. It was found that jointed lining carried smaller value of maximum bending moment than the non-jointed one. The reduction in bending moment, represented by the parameter called moment reduction factor, can be simply expressed as a function of angular joint stiffness and number segment.