الفهرس | Only 14 pages are availabe for public view |
Abstract This study deals with the statical design of syphons and tunnels with circular cross sections, which are executed using tunnelling boring machine (TBM). These structures are widely used in Egypt nowadays such as El-Salam syphon, Cairo underground metro project, and Cairo waste water project. In such cases, the structure is located at different depths from ground surface, and passes through different soil formations, all these parameters have to be considered in the design of cross sections of these structures. The study proposes a simple design method for these cross sections to estimate the maximum bending moment based on the design of fully embedded circular section in an elastic medium without any tensile forces between the section and the surrounding soil. A general solution was reached in the form of a universal chart to give the maximum bending moment in a section of radius ”r”, moment of inertia ”Is”, modulus of elasticity of liner material ”Ec”, and modulus of elasticity of soil ”Es” or coefficient of subgrade reaction, in a general dimensionless parameter ”(Es.r)/(Ec.Is)” . Also the solution is extended to solve the case of segmented liner formed of 8 or 16 segments per ring, with the existence of packer material at joints having modulus of elasticity varied from 1/100 to 1/1000 the modulus of elasticity of concrete. The solution is also plotted in universal charts. The given charts can help the designer to choose the proper thickness, the number of segments per ring and the packer material characteristics. As the given charts reflect the effect of these parameters on the resulting bending moments in the cross section with a relatively very little effort. Also from these studies many conclusions are reached. KeyWords: Tunnels, Syphons, Liner Design, Segmented Liner, Packers |