Abstract The study of minimum thickness of waterproof slab in long and deep tunnels is very significant in the process of engineering design and construction. A three-dimensional model test system for simulation of water inrush geohazards was developed. The test system has a three-dimensional model test device,a sample molding device and a device simulating tunnel excavation and unloading,so that the initial in-situ stress,water environment and process of tunnel excavation and unloading can be simulated. The test system is convenient and easy to operate and has the characteristics of short testing period and good loading stability. The system can carry out tests of large number of samples for statistical analysis and accurately simulate the process of excavation of the tunnel. Model tests were performed to simulate the water inrush geohazards at Longmen mountain tunnel of Chengdu to Lanzhou railway line. The confining and axial pressures of the test were both set as 0.6 MPa and the water pressure was 0.2 MPa. In this case,the minimum thickness of waterproof slab was 47 mm. The test results were used to guide the design and construction of the projects.
|
|
|
|
|