A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Convergence-confinement analysis for tunnels with combined bolt–cable system considering the effects of intermediate principal stress
The mechanical responses of tunnels reinforced by combined bolt–cable system are investigated in this paper. An analytical model of the convergence-confinement type is proposed that accounts for the sequential installation of finite-length fully grouted bolts and cables, as well as the effects of intermediate principal stress. The rock mass is assumed to be strain-softening material, obeying the unified strength theory or the Drucker–Prager criterion. The analytical model is divided into three stages including before bolt installation, bolt–rock interaction and after cable installation, of which the latter two stages are the focus of this study. According to the distribution and extent of the plastic zone and the relative bolt–cable lengths, six forms during the bolt–rock interaction and ten forms after cable installation are categorized and solved. Using the critical support pressures for the transitions of different forms, the modified whole-process ground reaction curve is obtained and validated by 2D numerical simulations and an existing model. Furthermore, the fictitious pressure is introduced to quantify the three-dimensional space effect of the tunnel face, whose solution is given by combining the proposed ground reaction curve and the longitudinal displacement profile proposed by Hoek. By using the strain compatibility conditions of bolts, cables and rock, the longitudinal tunnel displacement, stresses and plastic radii considering the sequential installation of bolts and cables are obtained. The results of the proposed model agree well with the 3D numerical simulations. Parametric analyses are conducted to investigate the effect of intermediate principal stress on the tunnel responses by different criteria. The proposed model provides a convenient alternative tool for the combined bolt–cable design of tunnels at the preliminary stage.
Convergence-confinement analysis for tunnels with combined bolt–cable system considering the effects of intermediate principal stress
The mechanical responses of tunnels reinforced by combined bolt–cable system are investigated in this paper. An analytical model of the convergence-confinement type is proposed that accounts for the sequential installation of finite-length fully grouted bolts and cables, as well as the effects of intermediate principal stress. The rock mass is assumed to be strain-softening material, obeying the unified strength theory or the Drucker–Prager criterion. The analytical model is divided into three stages including before bolt installation, bolt–rock interaction and after cable installation, of which the latter two stages are the focus of this study. According to the distribution and extent of the plastic zone and the relative bolt–cable lengths, six forms during the bolt–rock interaction and ten forms after cable installation are categorized and solved. Using the critical support pressures for the transitions of different forms, the modified whole-process ground reaction curve is obtained and validated by 2D numerical simulations and an existing model. Furthermore, the fictitious pressure is introduced to quantify the three-dimensional space effect of the tunnel face, whose solution is given by combining the proposed ground reaction curve and the longitudinal displacement profile proposed by Hoek. By using the strain compatibility conditions of bolts, cables and rock, the longitudinal tunnel displacement, stresses and plastic radii considering the sequential installation of bolts and cables are obtained. The results of the proposed model agree well with the 3D numerical simulations. Parametric analyses are conducted to investigate the effect of intermediate principal stress on the tunnel responses by different criteria. The proposed model provides a convenient alternative tool for the combined bolt–cable design of tunnels at the preliminary stage.
Convergence-confinement analysis for tunnels with combined bolt–cable system considering the effects of intermediate principal stress
Acta Geotech.
Sun, Zhenyu (author) / Zhang, Dingli (author) / Fang, Qian (author) / Huangfu, Nanqi (author) / Chu, Zhaofei (author)
Acta Geotechnica ; 18 ; 3323-3348
2023-06-01
26 pages
Article (Journal)
Electronic Resource
English
Analytical model , Combined bolt–cable system , Fictitious pressure , Intermediate principal stress , Ground reaction curve , Longitudinal tunnel displacement Engineering , Geoengineering, Foundations, Hydraulics , Solid Mechanics , Geotechnical Engineering & Applied Earth Sciences , Soil Science & Conservation , Soft and Granular Matter, Complex Fluids and Microfluidics
| British Library Online Contents | 2002
Improved Longitudinal Displacement Profiles for Convergence Confinement Analysis of Deep Tunnels
| Online Contents | 2009
Improved Longitudinal Displacement Profiles for Convergence Confinement Analysis of Deep Tunnels
| Online Contents | 2009