Profile image method and back-analysis of ambient stress changes
Date Issued
2008
Date
2008
Author(s)
Hsu, Chih-Hao
Abstract
As a result of the complex geological conditions and frequent plate movement, tunnel excavation and loading result in tunnel deformation in Taiwan. Regular survey is very important to assure the safety of tunnel. However, the traditional methods of tunnel survey take lots of time and money but get few tunnel profile information.herefore, this research develops a more efficient technique called Profile Image Method to get the tunnel profile. In order to generalize the tunnel deformation behavior, several tunnel loading cases are built by finite element analysis software ABAQUS. In short, this research includes the Profile Image Method and the study of the back-analysis of ambient stress changes. In the part of profile image method, the image processing toolbox in MATLAB is used to calibrate the images. Then, based on the laser scanning and selecting technology (Ni and Capart, 2006), the laser points can be picked and the coordinate can be got.n the study of the back-analysis of ambient stress changes, this research not only adopts the displacement separation method built by Ya-Ju Chiu (2007) but also take off the influence of rigid body rotation. By using the finite element analysis software ABAQUS, the far field force, local field force, un-symmetrical force and existing layer cases are designed. Then, by using the displacement separation method, the tunnel deformation can be got. In order to generalize the deformation behavior and its loading type, this research defines a parameter β to express.y the development of the profile image method and back-analysis of ambient stress changes, engineers can enforce the regular survey and judge where the failure would happen and the stress increment from survey data. Because of the critical data, engineers can predict the deformation tendency and reinforce the tunnel lining.
Subjects
tunnel
laser
image processing
Profile Image Method
stress changes
Type
thesis
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