Evaluation of the Clay Cutting Test - Assessment of a new method for measuring undrained shear strength in soils through comparative testing
Ladda ner
Publicerad
Författare
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The Clay Cutting Test (CC-Test) is a newly developed laboratory method to assess
the undrained shear strength of soil samples. Unlike other tests that provide a single
value of strength, the CC-Test presents a continuous strength profile by measuring
the resistance as a thin wire cuts through the soil sample. This thesis evaluates the
CC-Test through a combination of archive data comparison and in-depth study of
strength profiles from clay samples of varying depths.
In the archive compilation, representative values of shear strength from the CC-Test
were compared to those obtained with direct simple shear (DSS) and fall cone test.
For strengths below 25 kPa a good agreement between the methods was observed.
At higher strengths, the fall cone becomes less reliable and the DSS data are limited.
A parameter study indicated that density, water content and thread diameter have
an impact on the measured resistance. However, in the range of typical soils, the
deviation of the parameters is within ± 10% of the measured strength.
The in-depth analysis focused on 12 stiffer clay samples from 7-35 m depth. For each
sample, uniaxial compression test (UCT), CC-Test and fall cone test were conducted
on the same specimen, to minimize deviation due to natural variation of the soil. The
CC-Test yielded higher values than the fall cone and generally lower than the UCT.
For samples below 20 m, even the upper quartile of the CC-Test strength profile
could be considered conservative compared to UCT. The correlation between the
CC-Test measurements and the UCT was strongest near the locations corresponding
to the ends of the shear plane. In some tests, oscillating patterns appeared in the
measured strength curves, implying an effect of minor material changes within the
soil. These patterns were also present in reference tests, indicating they are not
caused by prior loading or sample disturbance.
The CC-Test shows potential as a complement to established methods for deter mining undrained shear strength due to its simple setup, fast execution, and ability
to present strength variation within the soil specimen. This makes it particularly
useful in quality control of soil samples. For it to be accepted in the industry, clear
guidelines on how to interpret the data is crucial. Further development, such as
measuring the remoulded shear strength with the CC-Test would further strengthen
its applicability.
Beskrivning
Ämne/nyckelord
CC-Test, wire penetration test, soil characterization, soil testing, undrained shear strength, Clay Cutter, Clay Cutting Test