Geology Reference
In-Depth Information
Colluvium
100
Failed mass
Volcanic
rock
90
Original
ground
level
80
700 mm thick and
laterally very
extensive zone of
caly-bound breccia
Seepage
above
fault after
failure
Failure
surface
70
Cut slope
at time of
failure
Volcanic
rock
60
mPD
Figure B1-2.3 Cross section through slope showing original and cut slope pro
le at the time of failure.
Geology is interpreted frommapping of the failure scar, but the main fault could be identi
ed in boreholes
put down before the failure occurred.
trimmed-back slope above the apartment blocks.
measures could be designed (Clover, 1986). It was fortunate that the failure occurred before construction
of the apartment blocks at the toe. The site as in 2010 is shown in
Figure B1-2.4.
The slope required
extensive stabilisation with cutting back and installation of many ground anchors through concrete
beams across the upper part of the slope and through the fault zones. These anchors will need to be
monitored and maintained continuously for the lifetime of the apartments.
