Tunnel and shaft solutions brochure - Humes

Joint and connection details
Circle joints
A self-locking plastic connector provides a robust joint
fixing for tunnel linings.
The connector is manufactured from a high strength
durable plastic. It combines the advantages of a bolted
connection with the speed, economy and alignment
characteristics of a dowel.
The system has been developed in conjunction with
major tunnelling contractors and is suitable for use in
traditional open face shields or with the latest full face
tunnel boring machines.
The self-locking connector offers many benefits:
• The dowels allow a very fast ring erection sequence.
• They are designed to reduce lipping between segments.
Figure 1 – Circle joint detail
4 Tunnel and shaft solutions
High strength dowel
giving self alignment and
good shear connection
• The system is tolerant of a dirty environment and
allows for the initial misalignment of segments to
compensate for tapered joints and gaskets.
• Highly durable connection with no corrodible parts.
• The rigid dowel action of the coupler re-aligns the
segment and minimises the stepping of joints.
• Self-locking and self-aligning.
• No circle joint pockets to fill, thus reducing
finishing time.
• Suitable for use with all types of sealing systems,
including Ethylene Propylene Diene Monomer (EPDM)
compression gaskets and hydrophilic seals.
• Does not induce bursting forces in the concrete.
• Fully compatible with elastic compression gasket. The
elastic performance of the connection compliments
the behaviour of the gasket, which means that it can
be used with a stiff gasket and copes with varying
joint gap.
Movable plastic
anchors allow segment
to be located when
imperfectly aligned
Threaded screw
connection which
allows a push fit
Shield ram thrust