Tunnel construction projects are subject to a very high level of complexity. Variations in soil conditions, different rock types, and high-water pressure are factors that place high demands on the construction. To meet these demands, Datwyler is continuously advancing the development of their products. An example is Datwyler’s Performance Corner, which was first used in 2015. Customer requirements for the corner design in machine-operated tunnel construction have increased enormously in recent years. The Performance Corner is Datwyler’s answer to these evolving needs.
The special properties of the Performance Corner are designed to ensure that the tunnel is leak-tight throughout various geologies and water pressure. It is essential that the right adjustments are made for the corner to guarantee the perfect fit of the gasket in the segment. The custom fit results from the combination of the correct cutting angle at the end of the segment and the right adjustments to the opening and torsion angles, which are taken from the ring design for the segments. The accurate torsion angle prevents both the corner from tilting and the formation of an additional offset to the adjacent gaskets. Datwyler closely reviews the specifications of all projects regarding the required tightness of the seal, its spalling behavior, and the resulting corner geometry. This includes the exact evaluation of the position of the gasket groove. Thus, a decision is made regarding the chamfer angle at the end of the profile section, the respective injected volumes, and to what extent the opening angle and torsion angle need to be adjusted. The profile length can be cut at 30°, 50°, or 90° in order to control the injected volumes.
The Performance Corner is manufactured with the injection molding process, which allows variable corner length, varying degrees of hardness and therefore higher retaining forces in the corner area. To prevent the Performance Corner from tearing or moving during the installation process, these retaining forces are a necessary counterpart for the high compression force, which occurs between the concrete segments when they are installed. The individually adjusted corners provide the required seal in the tunnel later. The Performance Corner consists of EPDM, which is also the basic material of the profile itself. EPDM allows a good connection to the profile, which guarantees the required high tear resistance for the frame corner during the assembly of the gasket frames and the installation of the segments. With regard to the long-term relaxation, EPDM ensures that the structure is leak-tight throughout its entire service life and that it has very good ozone, aging, and weather resistance. For special requirements, for example hydrocarbons-contaminated soil, the Performance Corner can also be made of chloroprene rubber (CR). Materials with an antibacterial effect could be used as well in the construction of tunnels for drinking