Geology Reference
In-Depth Information
Main geotechnical considerations when conducting site investigation
Issues
Equation 1
Equation 2
Equation 3
Geology
Environment Construction
Material
Mass
Arch dam
stability and
construction
Strength, deformability and
durability of foundation materials,
including highly stressed abutments
Geological pro
le, depth to bedrock
Presence of discontinuities, allowing
failure in abutments or sliding
failure below dam
Fault reactivation
Seismicity
Water pressure
in foundations
and abutments
Check history
of mining
Adequate
source of non-
reactive
aggregate
Waste disposal
locations (
ll
embankments)
Leakage
below dam
and from
reservoir
Permeability (need for grouting/cut
offs)
Potential for piping
Leakage on main fault and other
faults/weathered zones
Limestone might be karstic
Groundwater
profile in
surrounding
terrain
Existing
throughow
paths
Options for
grouting and/or
cut-off
structures
Landslides
into reservoir
Material strength
Adverse discontinuities, aquitards
causing perched water pressure to
develop
Landslide history
Response of
groundwater
to storms and
to lowering of
water in
reservoir
Seismic
loading
Need for
stabilisation
such as
drainage or
option to
remove
hazardous
ground
Powerhouse
and high-
pressure
tunnels
Rock strength Abrasivity for tunnel
equipment
Fracturing (rock mass classi
cation
allows judgement of stabilisation
required) Weathered zones
In situ stress
state (potential
squeezing or
leakage and
need for steel
liners)
Groundwater
pressure and
permeability
(inflows or
water loss for
operating
tunnels)
Method of
excavation
Ground
movement due
to excavation
Blasting
vibration
Groundwater
changes
4.4.1 General
At many sites, geologists can get a great deal from examining the
landscape, mapping and interpolating information from exposures,
and this is one of the most important aspects of geological education
and training. This, together with desk study information, should allow
preliminary ground models to be developed, which can then be used to
