Model tests on bearing characteristics of basalt fiber-reinforced concrete tunnel linings

Basalt fiber is a kind of inorganic material, which is effective and environmentally friendly. Basalt fiber concrete has important mechanical advantages to control the deformation of soft rock tunnels because it has functions such as strengthening, toughening, crack resistance and so on. Through the indoor model tests on mechanical behaviors of reinforced concrete and basalt fiber-reinforced concrete, the bearing characteristics of lingings of basalt fiber concrete linings are investigated. The test results show that compared with that of the reinforced concrete lining, the initial crack load of the basalt fiber concrete lining increases by 20 percent. The lining structure gets tougher after it is mixed with basalt fiber, moreover, after occurrence of the initial crack, the linings can also bear larger bending moment and deformation. The bearing characteristic curves of linings of the reinforced concrete and basalt fiber concrete exhibit linear change before the initial crack. After the initial crack, the curve of the reinforced concrete rises slowly before rapid convergence. The curve of the basalt fiber concrete increases to two times the value of the initial crack load and there is no convergence trend. Therefore, the basalt fiber concrete can satisfy both the requirements that the rock surface of the soft wall rock tunnel should be closed as soon as possible and the linings can provide supporting force with a certain deformation ability as soon as possible. The research results are extremely important to the control of large deformation of soft rock.