Model tests and bearing characteristics of composite lining of tunnel

The mountain tunnels in China often use composite lining support. To explore the bearing characteristics of the composite lining to guide the design of the mining method tunnel is of great significance. A large tunnel structural model test system is designed to carry out large-size model tests on the unsurported, spray-anchor combined support and composite lining support. The whole process of tunnel damage is monitored, and the damage modes of tunnels under different forms of support and the stress characteristics of the support structure are analyzed so as to reveal the bearing characteristics of composite lining. The results show that the composite lining support increases the design bearing capacity by 33.3% compared with the combined spray-anchor support. Under the two forms of support, the surrounding rock can withstand about 60% ~ 75% of the external load, and after its application, the secondary lining can share about 15% ~ 80% of the pressure of the surrounding rock. The combined spray-anchor support can better use the effects of anchors compared to the composite lining.