الفهرس 
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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