Abstract
Experimental studies show that local earth pressure acts on existing shield tunnel, when open cutting or shield tunnelling is performed nearby.
The aim of this paper is to present a numerical method of a psudo-three dimensional analysis of segment rings under patch loading.
The present method is based on the following assumptions:
1) Behavior of shield tunnel in the longitudinal direction is analogous to that a simple beam on elastic foundation.
2) Cross-sectional deformation of segment rings under patch loading can be approximately estimated by the cylindrical shell theory.
In view of these assumptions, the longitudinal rigidity of shield tunnel can be replaced by the equivalent spring constant related to the longitudinal deflection.
As a result, bending moment of segment rings with staggered joints is obtained through analyzing circular beams of two ring model supported elastically by the spring.
