Study On Calculation Models And Mechanical Characters Of Shield Tunnel With Double Lining

The using attribute of shield tunnel has already extended from road, municipal engineering to railway, hydraulic engineering. Double lining is a kind of the important shield tunnel structure forms which must be used. Based on the background of Shanghai-Nantong railway Huangpu River underwater shield tunnel project, this paper takes the design and calculation models and mechanical characters of shield tunnel with double lining as research object. Using research materials investigation, theoretic analysis and numerical simulation, it makes some useful researches. The main contents can be listed as follows.(1) Investigating the issues exposed in previous practice of single layered segment lining for shield tunnel and service condition and structure forms of double layered linings at home and abroad, it expounds research purpose and significance of double layered linings of shield tunnel.(2) With the existing calculation theory and research results, it establishes shell-spring calculation model under load-structure mode by introducing Reissner-Mindlin plate and shell theory..(3) This paper computes the internal forces of double layered linings with shell-spring model for difference typical sections along Huangpu River. Studying on the effects of key parameters of lining structure on internal forces, it gives some suggestions to take proper values of these key parameters.(4) With the current national standard, this paper simply discusses on measures of waterproof and drainage. And also it checks the bearing capacity of internal lining.From the contents above, this paper puts forward that double lining of shield tunnel can be divided into iterative structure and compound structure because the difference of interface. Iterative structure can share the loads according to the stiffness ratio between segment lining and internal lining; compound structure can establish displacement compatibility equation to solve the internal forces with variational principle in elasticity according to the shear strength of contact surface. According to the calculated results of internal forces, compound structure performance better on global stress; the shear strength and the thickness of secondary lining have obvious influence on the values and distribution of internal forces.