Shear stresses around circular cylindrical openings
P.C.J. Hoogenboom1, C. van Weelden1, C.B.M. Blom1, 2
1 Delft University of Technology, the Netherlands
2 Gemeentewerken Rotterdam, the Netherlands
In this paper stress concentrations are studied around circular cylindrical openings or voids in a linear elastic continuum. The loading is such that a uniform shear stress occurs in the continuum, which is disturbed by the opening. The shear stress is in the direction of the centre axis of the opening. The stress distribution has been determined both analytically and numerically. It is shown that a peak shear stress occurs next to the opening. The peak shear stress is twice the shear stress at a large distance of the opening. In addition, a lining has been considered and formulas have been derived to calculate the stresses in the lining.
The results are applied to a reinforced concrete bore tunnel in a soft soil. The soil is deformed in shear at the connection of the tunnel to a ventilation shaft. It is shown that large shear stresses can occur in the concrete due to minor differential settlements.
Key words: Stress concentration, shear, cylindrical void, lining, tunnel, soft soil, reinforced concrete