Geoscience Reference
In-Depth Information
the conventional handwritten methods. The preferences of having a hard copy
and not relying on electronic logging in these situations are another argument
not in its favour in such cases. The use of coded symbols aids in faster input of
the data.
4.4 Field testing
•
The common field testing is shown in the table.
Table 4.4
Type of field testing.
Symbol
Test
Measurement
DCP
Dynamic cone penetrometer
Blows/100 mm
SPT
Standard penetration test
Blows/300 mm
CPT
Cone penetration test
Cone resistance q
c
(MPa); friction ratio (%);
CPTu
Cone penetration test with
Cone resistance q
c
(MPa); friction ratio (%); pore
pore pressure measurement
Pressure (kPa). Time for pore pressure
(Piezocone)
dissipation t (sec)
PT
Pressuremeter test
Lift-off and limit pressures (kPa),Volume
change (cm
3
)
PLT
Plate loading test
Load (kN), deflection (mm)
DMT
Dilatometer test
Lift-off and expansion pressures (kPa)
PP
Pocket penetrometer test
kPa
VST
Vane shear test
Nm, kPa
WPT
Water pressure (Packer) test
Lugeons
- There are many variations of tests in different countries. For examples the
DCP, has differences in weight, drop and rods used. The CPT has mechanical
and electric types with differences in interpretation.
- Vane shear test may have a direct read out for near surface samples, but with
rods with a torque measurement for samples at depth.
4.5 Comparison of in situ tests
•
The appropriateness and variability of each test should be considered. An appro-
priate test for ground profiling may not be appropriate for determining the soil
modulus.
•
Variability in testing is discussed in section 10.
4.6 Standard penetration test in soils
•
In soils, the SPT is usually terminated with 30 blows/100mm in the seating drive
as a refusal level for the Australian Standard AS 1289 - 6.3.1 - 1993.
•
In rock this refusal level is insufficient data. British Standards BS 1377:1990 and
ASTM Standard D1586-84 allows further blows before discontinuing the test.
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