A series of unconsolidated-undrained (UU) triaxial tests are performed in order to examine the effect of strain rate and confining pressure on strength and stress-strain behavior of reconstituted saturated clays. Strain rate is controlled to vary between 0.015 %/min and 3.75 %/min. It is found by comparing the experimental data that strength and stress-strain behavior are mainly affected by strain rate

however

they are almost independent on confining pressure. Undrained shear strength of the saturated clay increases with increase of strain rate; and the increase of 70 % of strength may be attained. An empirical correlation between strength and strain rate is proposed after a given normalization. Furthermore

the hyperbolic constitutive model of nonlinearity is recommended in order to take the effect of strain rate on the stress-strain relation into consideration; and the experimentally-based procedure for defining the parameters in the hyperbolic model is given. The model is verified through test data in the monotonic triaxial and torsional shear tests.