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| Calculation method of stress and deformation of loess tunnel based on quadratic parabolic strength criterion of loess |
| CAO Zhouyang1, GUAN Xiaodi2, MA Di3, DOU Guotao1, ZHU Yongfeng4
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1.School of Civil Engineering and Architecture, Zhengzhou University of Aeronautics, Zhengzhou 450046, Henan, China;
2.School of Civil Engineering and Architecture, Xi'an University of Technology, Xi'an 710048, Shaanxi, China;
3.School of Civil Engineering, Xi'an Traffic Engineering Institute, Xi'an 710300, Shaanxi, China;
4.School of Geological Engineering and Geomatics, Chang'an University, Xi'an 710061, Shaanxi, China |
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Abstract The problem that the stress and displacement of surrounding rock in loess tunnels may cause large errors based on the Mohr-Coulomb strength criterion. A new solution for calculating the stress and displacement of the surrounding rock of the loess tunnel was derived based on the quadratic parabolic strength criterion, which could comprehensively consider the tensile and shear strength characteristics of the loess. The analysis showed that the peak value of tangential stress of tunnel surrounding rock appeared at the elastic-plastic interface. The peak value of tangential stress based on quadratic parabolic strength criterion was 6.1% lower than that based on Mohr-Coulomb strength criterion, and the stress in plastic zone of the former was smaller than that of the latter. The plastic zone radius of loess tunnel surrounding rock increased with the decrease of supporting force. When the supporting force was small, the plastic zone radius of the former was larger than that of the latter, and the smaller the supporting force, the greater the difference between the two. The peripheral displacement of loess tunnel increased with the decrease of supporting force, the former was larger than the latter, and the difference between the two increased gradually with the decrease of supporting force. By comparing the surrounding rock stress of the loess tunnel under different strength criteria with the model test results, it was found that the surrounding rock stress of the loess tunnel based on the quadratic parabolic strength criterion was in good agreement with the model test results. It showed that the surrounding rock stress, plastic zone radius and tunnel surrounding displacement of loess tunnel based on the quadratic parabolic strength criterion were closer to engineering practice.
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Received: 30 April 2022
Published: 20 December 2022
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