The principle of the testing method is to use the stress-control type loading from the start of the test until failure is approached and then switch to strain-rate control, as shown in Fig. 2. The times required pore-pressure equalization or sample drainage, depending on test type, be observed during the incremental loading portion of the test. Tim o dependent or creep deformations may be studied during this phase as The observed equalization or drainage times during the stress-cont portion of the test can then be used to establish a sufficiently slow ratéA