Research On The Durability Of The Fo-ling Tunnel's Lining Structure

ABSTRACT:At present, China is in the golden age of infrastructure. A large number of subway tunnels, high-speed railways and roads, subsea tunnels are being constructured. It is like a raging fire to meet the requirement of transport infrastructure to be improved day by day. At the same time, the durability of these structures has attracted more and more attention of academic and engineering circles. These facilities are almost impossible to be used effectively if the quality couldn't be assured. But now, the research on tunnel lining structure's durability is not perfect enough for engineering application. Therefore, it is very essential and meaningful to carry on researching some key technologies of durability of tunnel lining structure.Based on these problems above-mentioned, this thesis does some durability research on the Fo-ling tunnel's lining structure. The main works are as follows:(1) Firstly, in order to get some necessary concrete and rock parameters, for example, elastic modulus, cohesion, internal friction angle, I did some compressive and creep tests in shool's laboratory. And creep tests could also fit the generalized Kelvin model parameters.(2) The time interaction between supporting structure and surrounding rock in the circular tunnel is deduced through viscoelastic analytic method. Then, the Fo-ling tunnel is equivalent to round, the above result is applied to observe Fo-ling tunnel's deformation and force changes with time effect.(3) By ABAQUS simulation, the law between the axial and cohesion, internal friction angle, elastic modulus, lining thickness is known. And the mathematical prediction of the lining's axial stress is given by regression analysis. At last, I evaluate the reliability and failure probability in the different lining thickness.(4) Two main durability factors, including concrete carbonation and steel corrosion, are described simply. Then, based on crack limit and bearing capacity limit criterion, Fo-ling tunnel lining service life is forecasted.(5) The full research on the tunnel lining structure durability design theory has been carried on. The tunnel lining structure durability design method based on approximate probability has been established and the Fo-ling tunnel durability design limit state equation is obtained. Some special engineering measures are proposed to improve the lining durability from lining composition, raw materials and construction quality.