Volume 7, no. 13 - Colbond Geosynthetics

Once the drainage layer and liner are in place and tested
for leakage, the concrete inner wall of the tunnel is applied
directly over the liner. For this purpose, a special shuttering
machine is used.
For open-cut tunnels, obviously, a very different technique is
applied. Here the separate, pre-fabricated segments of the
tunnel are put in place and sealed against leakage with
bitumen strips. Enkadrain TP, for example, is then applied to
protect the seals and provide drainage. A major advantage
of Enkadrain TP in this respect is that it works when
installed either vertically or horizontally, and can therefore
protect open-cut tunnel roofs as well.
Both Enkamat and Enkadrain provide excellent permeability
and transmissivity, and can protect the waterproof liner
against puncturing. A good reason for many of the world’s
most demanding tunnel-builders to specify these
geo-spacers.
Colbond Geosynthetics News 13 - 2002
19