Soil Tests (site classification) for residential
dwellings, industrial, commercial and institutional buildings
are required to assess the subsurface conditions and therefore
enable design of appropriate foundations.
STA Consulting Engineers regularly undertake these types of
investigations in accordance with the Australian Standards:
AS2870-1996: "Residential
Slabs and Footings - Construction" and
AS1726-1993: “Geotechnical
site investigations”
Your site is classified based upon the expected movement of
the foundation soils - generally related to the capacity of
the soil to shrink and swell.
The following classifications may be typically given:
CLASS 'A' - Little
or no ground movement
CLASS 'S' - Slightly
reactive sites
CLASS 'M' - Moderately
reactive sites
CLASS 'H' - Highly
reactive sites
CLASS 'E' - Extremely
reactive sites
CLASS 'P' - Problem
site
The site classification is presented by STA Consulting Engineers
in a formal report which generally forms part of a building
application.
A skilled geotechnical consultant can usually gain all the information
for the soil test by digging into the soil profile and carrying
out some field tests and carrying out laboratory test for selected
samples by using specific instruments.
The ability to correctly identify the soil comes with training,
experience and knowledge of local area. Often soil samples are
collected and tested in laboratories in order to determine soils
types and their respective behaviour predictions.
The soil samples can be collected in a variety of ways, including
by hand auger, drill rig or backhoe.
Other equipment or tests you may see referred to include: VANE
SHEAR APPARATUS – used to measure the cohesion of clay
soil, hence calculate its strength and bearing capacity. PENETROMETER
TEST or DCP (dynamic cone penetrometer) - used to measure the
field density of soils so that the strength and bearing capacity
can be determined.CBR TEST, LINEAR SHRINKAGE, CORE SHRINKAGE,
and LIQUID LIMIT TESTS - these are all tests to measure the
properties of soil in the laboratory and help to predict its
behaviour on a site.
