Integrated Testing and Properties of a Gulf of Mexico Clay

In testing undisturbed soil samples taken in a hostile environment one is often faced with the problem of having to obtain many properties from a limited number of specimens. This difficulty can be partly overcome by designing compatible equipment, so that a sample can be tested in a nondestructive way at very small strains in one type of machine, then transferred to another one and subjected to larger static and dynamic stresses and strains. In this investigation, the specimens were first placed under fast cyclic loading axially and torsionally in the resonant column cell. Then they were transferred with their caps in place to another cell where they were subjected to slower cyclic loading under increasingly larger stress amplitudes. The results of the tests that were conducted on a Gulf of Mexico clay are given and analyzed. Shear moduli, damping ratios, and frequency responses obtained in a resonant column at very small strains are examined together with ratios obtained at large strains to give a complete picture of the dynamic behavior of this clay.

Data discussed in the light of the Ramberg-Osgood-Masing criterion show that such a criterion overestimates the damping and that it is impossible to describe the behavior of this clay over the whole spectrum of strain with just one set of parameters. It is recommended that parameters in the zone of interest always be obtained.