Abstract
Past studies on deep-lying tunnels under the assumption of plane strain have generally neglected the influence of intermediate principal stress even though this affects the surrounding rocks in the plastic zone. This study proposes a finite difference method to compute the stress strain plastic region and displacement of a tunnel based on the Drucker–Prager (D–P) yield criterion and non-associated flow rule and considering the influences of intermediate principal stress and the strain-softening behavior of surrounding rock. The computed results were compared with those of other well-known solutions and the accuracy and validity of the method were confirmed through some examples. Parameter analysis was conducted to investigate the effects of intermediate principal stress on stress-strain, the plastic region, the ground response curve, and the dilatability of surrounding rock. The results showed that the plastic radius Rp, the residual radius Rd, and radial displacement of surrounding rock first decreased and then increased with increasing intermediate principal stress coefficient b from 0 to 1, with the minimums occurring at b = 0.75. On the contrary, the peak and rate of variation of the dilatancy coefficient first increased and then decreased with increasing b and the dilatancy coefficient Kψ gradually transitioned from nonlinear to linear variation. Meanwhile, the inhibition of the plastic radius and radial displacement gradually weakened with increasing support pressure, whereas the dilatancy coefficient of the tunnel opening gradually increased.
Highlights
Underground tunnels dominate constructed underground structures in rock engineering and include highway and railway tunnels, underground workshops, mines, and hydraulic tunnels
The tunnel excavation surface is to the initial hydrostatic stress field of σ0, the plastic region with radius R p is formed by uniform distribution of with support pressure pi,surface and σis subject and σ the excavation of the tunnel radiusstructure r0
The present study proposed a numerical solution for determining the distribution of certain threshold, it promoted deformation of the surrounding rock
Summary
Underground tunnels dominate constructed underground structures in rock engineering and include highway and railway tunnels, underground workshops, mines, and hydraulic tunnels. Mohr–Coulomb (M–C) yield criterion or Hoek–Brown (H–B) yield criterion [4,5,6,7,8,9,10,11,12,13] These studies are of practical and theoretical value, they do not consider the effect of intermediate principal stress on the deformation and failure resulting from tunnel excavation. Zhang Qiang et al [20] applied the UST to study the effect of intermediate principal stress on the range of the fracture zone and deformation of the surrounding rock of a deeply buried tunnel They did not provide a method for calculating intermediate principal stress. Provide a significant theoretical foundation for the assessment of stability an design of a deeply buried tunnel
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
