Experimental study on mechanical behavior of single-layer lining of steel fiber reinforced concrete tunnel considering interlayer effect
Zhou Ping1 Wang Zhijie1 Lei Feiya1 Du Yanliang2 Hou Weiming1 Xu Haiyan1 Wang Li1
1. Key Laboratory of Transportation Tunnel Engineering of the Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China;
2. Structural Health Monitoring and Control Key Laboratory of Hebei Province, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
Abstract： In order to investigate the influence of interlayer contact on the internal force distribution of single-layer lining of steel fiber reinforced concrete tunnel, a single-layer lining model is designed, a horizontal loading test bench with the vertical oil pressure of 5MPa and the lateral pressure of 1.5MPa is developed, and the mechanical characteristic model test of single-layer lining of steel fiber reinforced concrete tunnel under different loads is carried out. The results show that both the single-layer linings with and without considering the contact characteristics between the two sides of the arch and the corner have the lowest safety factors, and the sudden changes in bending moment and the axial force are most likely to occur; For the case of the single-layer lining with the contact characteristics of interlayer considered, the maximum bending moment and axial force occur at the arch foot, obvious adhesion exists at the contact surface of interlayer, the axial force increases and bending moment of structure decreases, the internal force becomes balanced, and the overall safety of structure is higher than that without considering the contact surface; compared to the case without considering the interlayer effect, the safety factors at the most dangerous left and right arch feet were increased by 143.7% and 149.4%, respectively; When the vertical oil pressure reaches 3MPa and the lateral oil pressure reaches 0.9MPa, the interlayer contact pressure for the inverted arch increases significantly faster, and the concrete of the inverted arch changes from linear elastic state to plastic state; when the vertical oil pressure reaches 4MPa and the lateral oil pressure reaches 1.2MPa, the contact stress of inverted arch, arch foot and vault tends to be smaller or to increase reversely, so that the interfaces at the inverted arch and wall corner fail; steel fiber in single-layer lining with crack propagation between 30%~70% has the best crack resistant effect.
