Discussion: Constant rate of displacement test on ultra-soft soil

Abstract

H. P. Fitzpatrick and B. C. O’Kelly, Trinity College, Dublin, Ireland The authors have elucidated the underlying importance of using an appropriate strain rate (R) in order to obtain the true e–log 9 v response and the non-linear steady-state Cv and k values (Equations 8 and 9) from the constant rate of displacement (CRD) consolidation test, and their proposed method, based on estimated compression index values, for selecting a suitable strain rate for large-strain CRD testing of slurry sediments is welcomed. In carrying out a series of CRD tests for R between 0.01%/min and 0.1%/min on highplasticity clay (CH) slurry specimens, the authors rightly point out that the high measured pseudo-preconsolidation pressures, which clearly do not exist in reconstituted ultra-soft soil, are due to viscous effects during the test procedure.