Study On The Excavation And Supporting-Lining Mechanical Behavior Of Variable Section Cross Tunel

With the sustainable and rapid development of china economy,the construction of highway tunnel involved in the hydroelectric engineering,etc,goes to upsurge.we design a lot of variable section cross tunnel. Because its excavation and supporting-lining structure have complex stress, and interact each other greatly, so it has special requirements on the determination of excavation method, the reinforcement of rock and soil at cross tunnel, as well as the construction monitoring measurement. As the lack of research results of variable section cross tunnel(especially in variable section cross tunnel) in domestic and abroad, so analyzing the mechanics and deformation behavior of surrounding rock and supporting-lining structure of tunnel, discussing the deformation mechanism of surrounding rock of variable section cross tunnel, have the very vital significance on the improvement of the theoretical system and underground project construction.Main research results of this article is listed below:1、Collecte and analyse research results on cross tunnel stability in domestic and abroad,then analyse the specific application of the3-D elasto-plastic finite element method in stability analysis of cross tunnel, focuses the analysis on the basic principles and implementation steps.2、Take actual project as an example, firstly, discusse the initial stress field of surrounding rock and anchor bolt mechanism, then create3-D finite element model of varible section cross tunnel, use the ANSYS finite element software to calculate this model which is in class III and IV surrounding rock conditions, and two different excavation methods, get distribution characteristics of stress field, displacement field and plastic region of tunnel surrounding rock and supporting-lining structure.3、According to the numerical result, discusses the mechanism of surrounding rock deformation and failure,and influencing factors of instability.This research can provide scientificly and rationally guidance for the design and construction of variable cross section cross tunnel,and provide a reference for the similar project.