Numerical Modeling for a Highway Tunnel Construction and Structural Reliability Analysis
|School||Central South University|
|Course||Underground Space Science and Engineering|
|Keywords||Tunnel Construction Process Lining Artificial Neural Network Reliability|
With the rapid development of China’s transport sector, and the process of urbanization continuously pushed forward, underground construction in roads, railways and municipal construction in areas makes an unprecedented development, both in number and scale. Tunnel, as the most pervasive form of underground works, the number of its construction will also be increasing.The current methods of the existing tunnel support structure design is difficult to take into account a reasonable cross-section support structure and the bearing capacity and stability. In this paper, the structural reliability was applied to analyze the stability of tunnel engineering and make the design more rational, scientific, better reflect the essence of the problem.In this paper, take a separated highway tunnels as an example, which is in Gansu sector of Lianyungang-Huoerguosi speedway, the mechanical response in the tunnel construction process and reliability of the tunnel structure was systematically studied. Main contents of this article are as follows:(1) By the means of numerical modeling based on FLAC3D, tunnel construction process is simulated. According to the non-linear characteristics of geotechnical materials, the process of tunnel construction theory and numerical simulation methods are explained. Based on the FLAC3D modeling techniques and determination of the physical and mechanical parameters, initial conditions, boundary conditions, material constitutive, cell type of the grid, the plane geometry model of the tunnel was established. Two kinds of tunnel excavation construction process as synchronous excavation and asynchronous excavation were modeling by numerical simulation method, obtaining the distribution law of stress, strain and displacement under different conditions of construction;(2) Analysis on the stability problems of surrounding rock mass and supporting structure was carried. According to the interaction mechanism between the supporting structure and surrounding rock, the overall stability of the tunnel structure was studied. The reliability problems on structure were presented.(3) Taking the tunnels as the study subject and according to the ultimate limit states tunnel structure, the Monte Carlo method is used to calculate the reliability index; On account of the features of artificial neural network, try to compute the reliability index by programming in artificial neural network. By comparison of two methods, it proved that the structural reliability based on neural network method is indeed feasible.