Geoscience Reference
In-Depth Information
1.9 Volume sampled
•
The volume sampled varies with the size of load and the project.
•
Overall the Volume sampled/volume loaded ratio varied from 10
4
to 10
6
.
•
Earthen systems have a greater sampling intensity.
Table 1.9
Relative volume sampled (simplified from graph in Kulhawy, 1993).
Type of development
Typical volume sampled
Typical volume loaded
Relative volume sampled/
Volume loaded
Buildings
0.4 m
3
2
10
4
m
3
1
×
Concrete dam
10 m
3
5
10
5
m
3
1
×
Earth dam
100 m
3
5
10
6
m
3
10
×
1.10 Relative risk ranking of developments
•
The risk is very project and site specific, ie varies from project to project, location
and its size.
•
The investigation should therefore theoretically reflect overall risk.
•
Geotechnical Category (GC) rating as per Table 1.6 can also be assessed by the
development risk.
•
The variability or unknown factors has the highest risk rank (F), while certainty
has the least risk rank (A):
- Projects with significant environmental and water considerations should be
treated as a higher risk development.
- Developments with uncertainty of loading are also considered higher risk,
although higher loading partial factors of safety usually apply.
•
The table is a guide in assessing the likely risk factor for the extent and emphasis
of the geotechnical data requirements.
•
The table has attempted to sub-divide into approximate equal risk categories. It
is therefore relative risk rather than absolute, ie there will always be unknowns
even in the low risk category.
1.11 Sample amount
•
The samples and testing should occur every 1.5m spacing or changes in strata.
•
Obtain undisturbed samples in clays and carry out penetration tests in granular
material.
•
Do not reuse samples e.g. do not carry out another re-compaction of a sample
after completing a compaction test as degradation may have occurred.
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