Environmental Engineering Reference
In-Depth Information
Table 5.11.
Deficiencies in data presentation and interpretation.
Problem
Consequences
Remedy
Too much detail on irrelevant
Important features lost in
Proper planning and briefing
features, e.g. lengthy
the mass of irrelevant data.
of personnel by experienced
description of trench logs,
Misinterpretation of geological
geotechnical practitioners
or mineralogy of rock types
conditions, potential for
Clear distinction and
in borelogs. Confusion of
contractual claims
definition of terms
“facts” and interpretation
Straight line interpolation
Misinterpretation of
Draw interpretive sections with
between boreholes without
geological conditions,
due allowance for geology
regard for lack of data or
overconfidence in interpolation,
e.g. core stones in granite,
geological conditions
potential for contractual claim
buried land surfaces
Use of exaggerated scales in
Misinterpretation of geological
Use natural scale or provide
preparing sections
conditions, overconfidence in
both natural and
interpolation, potential for
exaggerated scale
contractual claim
Consideration of data on a hole
Misinterpretation of geological
Determine a proper
to hole basis
conditions, incorrect
geotechnical model of the
assessment of design parameters
site based on all data
and the range of values
Failure to recognise that it is the
Contractual claims
Recognise the importance
exception which sometimes
and include in reports and
causes the problems e.g. a thick
interpretive sections
bed of rock or a thin bed of high
strength rock causes problems
with rippability and size of
ripped material
Incorrect projection of
Incorrect interrelation of
Project along contour and/or
information from boreholes,
conditions
with consideration of
in particular altering levels
geological controls
Table 5.12.
Deficiencies in earthfill borrow area investigations.
Problem
Consequences
Remedy
Use of boreholes to
Failure to recognise variability
Use backhoe or excavator pits
investigate earthfill and
of soils, water contents incorrectly
where possible (
6m)
sand/gravel deposits determined, contractual claims
Lack of water content profiles, Lack of knowledge of moisture
Take profiles in period
or profiles taken in periods
condition requirements,
representative of construction
not typical of contract
contractual claims
Lack of information on
Deficiency of material when
Do density in place tests and
“bulking” factors in
“shrinkage” occurs leading to
laboratory compactions in
earthworks
contractual claims
borrow area investigations
Variability of alluvial and
Difficulty in selecting materials during
Dig plenty of test pits
non alluvial soil deposits
construction, contractual claims
investigation practice. In many cases these inadequacies only become apparent during
construction and lead to costly redesign and/or contractual disputes.
Tables 5.8
to Table
5.12 list some specific problems that occur in geotechnical investigations, the conse-
quences, and measures which can be taken to avoid the problems.
