Complements our static triaxial setups is our cyclical triaxial setup. In many ways, these tests relate to saturate and consolidate equal to the static tests, only the load phase can be carried out with a recurring pattern of load changes. This can be in the interests for research into dikes that have to do with waves, earthquake research, windmills, objects in the sea, driving of sheet piling and other situations which have to deal with fibrations.
Important in this is to investigate after how many cycles the water pressure in a sample increases so far - and thus the effective grain tension decreases - till you can finally speak of complete softening. This enables us to accurately identify, similarly, we can mention include the damping factor and shear modulus parameters here.
We are able to perform this test - according to ASTM D3999-91 - force controlled, so that you give command to apply sinusodial the same positive force (compression) and negative force (extension) upon the sample. Usually this happens undrained, so there will be no change in volume of the sample. It is also possible to perform the test pressure controlled (same as force controlled, but then let the circuit control take account into change of height and therefore change of average area during the cyclic phase). Finally, it is also an option to perform the test displacement controlled.
In consultation with the client we work with a number of laboratory specifications, including consolidation pressure, amplitude deviatoric stress and how many cycles per second (Hz). We can apply up to 2 Hz, commonly we use 0,1 - 1 Hz.