| Title |
Analysis of Nonlinear Behaviors of Shotcrete-Steel Support Lining Considering the Axial Force Effects |
| Authors |
유지환(Yu, Jeehwan) ; 김정수(Kim, Jeongsoo) ; 김문겸(Kim, Moon Kyum) |
| DOI |
https://doi.org/10.12652/Ksce.2017.37.2.0357 |
| Keywords |
강지보;숏크리트;합성단면;화이버 단면 요소;지반 강성;극한해석 Steel supports;Shotcrete;Composite cross-section;Fiber section element;Ground stiffness;Ultimate analysis |
| Abstract |
Bending and axial forces simultaneously occur at the cross-section of a shotcrete lining reinforced with steel supports due to the tunnel geometry. The shotcrete has changing flexural stiffness depending on the axial forces and, as a result, severely nonlinear behavior. The mechanical properties of a shotcrete-steel composite also depend on the type of steel support. This study presents a fiber section element model considering the effect of axial force to evaluate the nonlinear behavior of a shotcrete-steel composite. Additionally, the model was used to analyze the effects of different types of steel supports on the load capacity. Furthermore, a modified hyperbolic model for ground reaction, including strain-softening, is proposed to account for the ground-lining interaction. The model was validated by comparing the numerical results with results from previous load test performed on arched shotcrete specimens. The changes in mechanical responses of the lining were also investigated. Results show a lining with doubly reinforcement rebar has similar load capacity as a lining with H-shaped supports. The use of more materials for the steel support enhances the residual resistance. For all types of steel reinforcement, the contribution of steel supports during peak load decreases as the ground becomes stiffer. |