Part C - Minimum Requirements on geotechnical investigations 
27 
Table 8: Suitable laboratory tests for assessing cohesive soils. 
Test type 
Standard 
Quality class of sam 
ple 
(DIN EN ISO 22475-1) 
Soil mechanical 
parameter 
Classification and status description 
Particle size distribution 
DIN 18123 
Min. 4 
degree of non-uniform 
ity, coefficient of grada 
tion 
Water content 
DIN 18121-1 
DIN 18121-2 
Min. 3 
Water content of 
soil 
Water permeability 
DIN 18130-1 
minimum of grade 2 if 
sample has been ad 
justed to the required 
density using Proctor 
compacting equipment 
coefficient of water per 
meability 
Density 
DIN 18125-1 
Min. 2 
density, buoyant den 
sity 
Consistency limits 
DIN 18122-1 
DIN 18122-2 
Min. 4 
Liquid limit, plastic limit, 
shrinkage limit, plastic 
ity index, consistency 
index 
Deformation behaviour 
Compression test 
(oedometer test) 
DIN 18135 
1 3 
Stiffness modulus, Pre 
stressing of soil, coeffi 
cients of consolidation, 
secondary compres 
sion, water permeability 
Triaxial test 
DIN 18137-2 
1 3 
Shear stress-strain 
curves; volume change 
and axial deformation 
Shear strength 
Laboratory vane test 
Laboratory tests not 
currently standardised 
1 3 
Undrained shear 
strength cu 
Direct shear test 
DIN 18137-3 
1 3 
effective friction angle 
cp’, effective cohesion c’ 
Triaxial test 
DIN 18137-2 
1 3 
Shear parameters de 
pending on type of test: 
UU test: c u , cp u 
CU test: c’, cp’ 
CCV test: c’, cp’ 
3.2 Tests to analyze soil behaviour under cyclical loading 
Pressure changes in the soil can be either directly or indirectly induced by load transfer through 
the structure caused by waves, currents and wind; these can exert a crucial influence on the 
load-bearing behaviour of the soil and therefore also the foundation. Cyclical load actions 
must therefore be taken into account in an appropriate manner when measuring the founda 
tions (see e. g. DIN 1054). 
With regard to the grades which can be achieved, see Part C, Section 2.2.3.