Research on critical undrained strength of K-0 consolidated soft clays

K-0 ompression line and critical state line can be simplified as parallel straight lines in e-lg p' space within the framework of critical state soil mechanics. Inclined ellipsoid is the simplest yield surface shape of the model that can take account of anisotropy. Combined with critical state soil mechanics, formulas of undrained strength under K-0 consolidation have been proposed; these formulas can be used in triaxial stress conditions and plane strain conditions. Based on a large number of experimental data, the formulas are proved to be true. If other parameters taken as constant, we can get linear relations between the undrained strength ratio and the effective frictional angle. A simplified formula has been proposed for engineering application.