Establishment of Heterogeneous Equivalent Beam Model of Shield Tunnel and Analysis

At present mechanics models in designing shield tunnel segments include the homogeneous ring model,multi-hinge ring model,beam-spring model and so on.In this paper on the basis of analysis on the above models,from the angle of the mechanical properties of segment joint sections,a new mechanical analysis method of shield tunnels was put forward.The inhomogeneous equivalent beam model was built in which both joint elements and non-joint elements were simulated with beam elements of different equivalent parameters.The analytic equivalent parameters formulas of joint beam section properties,such as the height,width,elastic modulus and so on were deduced theoretically.According to field test data,the orthogonal test was applied to make back analysis on section properties equivalent parameters,verify the effectiveness of the above theoretical formulas,and get a group of section properties equivalent parameters under certain conditions.Comparing the results of internal forces of the new model with the results of the field tests and beam-spring model,it is seen that the internal forces of the control sections of the new model are safer than the field test data and the safety factor of the new model lies between the field test data and beam-spring model results.This model makes mechanical properties of segment joint clearer,and it can be popularly applied in engineering.