Tunnel
Stability Analysis of Tunnel Excavation
Aspillway tunnel for an embankment dam is to be constructed in a poor quality
sandstone. The excavated diameter of the tunnel is about
13m and the cover over the roof is 8m. The tunnel is to have a 1.3 m thick un-reinforced concrete lining
and,after placement of
this lifting, a 28 to high portion of the rockfill dam will he over the constructed tunnel.
The questions to be addressed are:
(1)What support is required in order to excavate the tunnel saf ...