Volume 6 – Geotechnical Manual, Site Investigation and Engineering ...

Chapter 6 SLOPE STABILITY
For surface drainages, cast in-situ drains
(both berm
drains and cut off drains) are strongly
recommended to avoid possible water infiltration through the poorly constructed gaps between
precast
drain sections. V-shape
drain should be used due to the effect of “self cleaning” even with
little water in the drain.
Figure 6.10 Good Drainage System Critical to Stability of Slope
6.7.3
Buttressing or Counter Berm
Buttressing is a technique used to offset or counter the driving forces of a slope by externally
applied
force system
that increases the resisting forces. Buttressess may consist of soil or rock fills,
and counterweight
berms.
Counter berm
Figure 6.11 Butresses or Counter Berm for Slope
Stabilsation
6.7.4
Soil Nailing
Soil nailing is a method of in-situ reinforcement utilizing passive inclusions thatt will be mobilized if
movement occurs. It can be used to retain excavations and stabilize slopes by creating
in-situ,
reinforced, soil retaining structures.
6-14
March 2009