COMPARISON OF INCREMENTAL LOAD AND CONSTANT RATE OF STRAIN CONSOLIDATION TEST RESULTS

The results of incremental loading (IL) consolidation tests and constant rate of strain (CRS) consolidation tests for the soil samples from 5 boreholes in Saga, Japan, have been presented, compared and discussed. Although there are scatters on test data, generally for the strain-rate tested (0.02% similar to 0.1%)/min, consolidation yielding stress (p(c)) increased with strain-rate. Comparing the p(c) values from the IL tests and the CRS tests, it is suggested that the p(c) values of CRS tests with a strain-rate of 0.02% similar to 0.03%/min are comparable with that of IL tests, and practically they can be judged as the similar. For undisturbed Ariake clay, e - ln(p') (e is void ratio and p' is consolidation stress) curve of CRS test is more non-linear than that of IL test. Considering the slope (lambda) of e - ln(p') curve just after yielding stress (p(c)), CRS test resulted in a larger lambda value then IL test even through there was not much difference on p(c) value. It is suggested to use a linear ln(e) - ln(p') relationship in settlement calculation rather than a linear e - ln(p') relationship for Ariake clays. The values of the coefficient of consolidation (C-v) from IL and CRS tests are comparable, but the values of the coefficient of hydraulic conductivity (k) reduced with the increase of strain rate.