Novel experimental method for rate-independent triaxial tests under partial drainage condition

A novel and yet simple technique for partially drained triaxial tests while preserving the assumptions of an element test is presented. The approach is based on the defined adjustment of the bulk modulus of a fluid system consisting of water and gas. Monotonic triaxial compression tests on Karlsruhe fine sand with different initial densities, sample preparation methods, loading rates and sample dimensions demonstrate the feasibility of the novel method. A drainage factor D_f is introduced, which describes the current state of the drainage possibility. This drainage factor is subjected to changes during the experiment.