U100 SAMPLER
U100 Sampler system for Geotechnical Site Investigation and Soil
Sampling
Geotechnical Site Investigation and Soil Sampling
In recent times Compact Lightweight Drilling and Sampling Machines
have become very popular.
Several companies manufacture excellent compact soil sampling
machines including:
U100 Sampler Equipment for this method of ground penetration and
sampling can be rapidly deployed on a trailer behind a 4×4 vehicle
or inside of a panel van.
The generally rubber tracked machines can move quickly around a
site causing minimal surface damage while obtaining good quality
representative samples of strata beneath the site usually to depths
of around 10mtr although in favourable conditions this depth can be
substantially increased.
Geotechnical Exploration Services carries out this work using
machines fitted with a drop hammer that can rapidly be replaced
with a rotary drillhead enabling penetration into bedrock including
coring to 50mtr.
A range of cutting and sampling tools has been designed for use
with this type of shallow ground investigation.
Concrete Coring Barrels
On many sites it is necessary to cut through concrete or tarmac and
other man made materials in order to gain access to the ground that
is to be investigated. A concrete cutting/coring barrel is used for
this and consists of a tube with a diamond impregnated shoe easily
capable of cutting the hardest of materials including reinforced
concrete. The top of the tube is fitted with a water swivel for
injection of water to cool the bit and clear drill cuttings.
Window & Windowless Sampling Tubes
Window sampling tubes are usually 1mtr – 2mtr long. They have a
cutting shoe on the leading edge and slots or windows up the side
which give direct access to the sample. They are driven into the
ground by a drop weight or hydraulic hammer. Casing is advanced
during sampling when needed to stabilise collapsing strata.
Other similar types of sampling tubes have no windows (windowless)
but have removable clear plastic liners which can be sealed to
maintain integrity and then cut open along their length in the
laboratory where they are logged, analysed and samples are tested
giving excellent representative information on the site being
investigated.
Other geotechnical information can be gathered during this type of
ground investigation.
Standard Penetration Tests (SPT) to BS1377B
A test to estimate the degree of compactness of soil in place by
counting the number of blows required to drive a standard sampling
spoon 1′ (0.3 meter) using a 140 pound (64 kilogram) weight falling
30″ (0.8 meter).
Dynamic Probing (BS 1377 Part 9)
This test is done to determine the penetration resistance of soil
and consists of dropping a hammer onto an anvil over a distance of
300mm and at a rate of between 20 and 60 blows per minute. The
anvil is directly connected via rigid rods to the probe which is
resting on the strata at the base of a hole. Blows are counted and
recorded for every 100mm of penetration.
U100 Sampling
This is a sampling method whereby a sampling tube is driven into
the ground (usually clay type material). Samples are retained in
the tube by fingers at the base which grip when the tube is lifted
from the base of the hole. There are several systems od U100
samplers – U100 Standard System, U100 Plastic Liner System & U100
Thin Wall System.
