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Geomechanics and Engineering
  Volume 22, Number 4, August25 2020, pages 277-290
DOI: http://dx.doi.org/10.12989/gae.2020.22.4.277
 


Solution for surrounding rock of strain-softening considering confining pressure-dependent Young\'s modulus and nonlinear dilatancy
Peng Liang, Yongtao Gao, Yu Zhou, Chun Zhu and Yanhua Sun

 
Abstract
    This paper presents an elastic-plastic solution for the circular tunnel of elastic-strain softening behavior considering the pressure-dependent Young\'s modulus and the nonlinear dilatancy. The proposed solution is verified by the results of the field measuring and numerical simulation from a practical project, and a published closed-form analysis solution. The influence of each factor is discussed in detail, and the ability of Young\'s modulus and dilatancy characterizing the mechanical response of surrounding rock is investigated. It is found that, in low levels of support pressure, adopting the constant Young\'s modulus model will seriously misestimate the surrounding rock deformation. Using the constant dilatancy model will underestimate the surrounding rock deformation. When adopting the constant dilatancy model, as the dilation angle increases, the range of the plastic region increases, and the surrounding rock deformation weakens. When adopting the nonlinear dilatancy, the plastic region range and the surrounding rock deformation are the largest. The surrounding rock deformation using pressure-dependent Young\'s modulus model is between those resulted from two constant Young\'s modulus models. The constant a of pressure-dependent Young\'s modulus model is the main factor affecting the tunnel displacement. The influence of α using a constant dilatancy model is much more apparent than that using a nonlinear dilatancy model.
 
Key Words
    circular tunnel; strain-softening behavior; Young\'s modulus; nonlinear dilatancy; generalized Hoek-Brown yield criterion
 
Address
Peng Liang, Yongtao Gao and Yu Zhou: Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mines, University of Science and Technology Beijing, Beijing 100083, China

Chun Zhu: 1.) School of Earth Science and Engineering, Hohai University, Nanjing, 210098, China
2.) State Key Laboratory for Geomechanics and Deep Underground Engineering, Beijing 100083, China

Yanhua Sun: School of Civil Engineering, Guizhou University of Engineering Science, Bijie, 551700, China
 

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