Site investigation - Geotechnical Investigation and Design Tables - page 15

•

Overall the % values for buildings seem low and assume some prior knowledge
of the site.

•

A value of 0.2% of capital works should be the minimum budgeted for sufficient
information.

•

The laboratory testing for a site investigation is typically 10% to 20%of the testing
costs, while the field investigation is the remaining 80% to 90%, but this varies
depending on site access. This excludes the professional services of supervision
and reporting. There is an unfortunate trend to reduce the laboratory testing,
with inferred properties from the visual classification and/or field testing only.

1.17 The business of site investigation
•

The geotechnical business can be divided into 3 parts (professional, field and
laboratory).

•

Each business can be combined, ie consultancy with laboratory, or exploratory
with laboratory testing:

- There is an unfortunate current trend to reduce the laboratory testing, and

base the recommended design parameters on typical values based on field
soil classifications. This is a commercial/ competitive bidding decision rather
than the best for project/optimal geotechnical data. It also takes away the
field/laboratory check essential for calibration of the field assessment and for
the development and training of geotechnical engineers.

Table 1.17 The three “businesses'' of site investigation (adapted from Marsh, 1999).

The services Provision of professional services Exploratory holes Laboratory testing

Employ Engineers and Scientists Drillers and fitters Lab technicians

Use Brain power and computers Rigs, plant and equipment Equipment

Live in Offices Plant Yards and workshops Laboratories and stores

QA with CPEng Licensed Driller,ADIA NATA

Invest in CPD and software Plant and equipment Lab equipment

Worry about

<

1600 chargeable hours

<

1600 m drilled a year

<

1600 Plasticity Index

achieving a year per member of staff per drill rig tested per year per

technician

CPENG Chartered Professional Engineer; CPD Continuous Professional Development; NATA National Association
of Testing Authorities;ADIA Australian Drilling Industry Association.