ABSTRACT
Kastner’s solution is often used in elastic-plastic analysis for surrounding rock of circular tunnel. There are obvious limitations in Kastner’s formula, which is based on ideal elastic-plastic constitutive model. This leads to the Kastner’s solution is far away to coresponding actual values in surounding rock of tunnel. Following along the path of pioneered by Kastner, researchers such as Ma (1995, 1996), Jiang and Zheng (1996, 1997), Ma (1998, 1999),Yu (2002), Fan (2004), Ren and Zhang (2001) and Pan and Wang (2004) published different solutions for surrounding rocks of circular tunnel. However, these solutions are resticted to very simple material models, such as simple linear relationship between stress-strain. They are of limited practical value. This study successfully gets the stress distribution laws of surrounding rock plastic and broken zone of tunnel according to the total strain theory. The relationship between equivalent stress and equivalent strain is deduced from practical rock. The relational expressions are related with triaxial stress (σθ , σz , and σr) and triaxial strain (εθ , εz , and εr) of surrounding rock.
