Effects of Isotropic Consolidation Time on Deformation Modulus of Soils in Small Strain Range

Hirofumi TOYOTA

Although the deformation modulus of small strain range can be measured using a triaxial apparatus with local strain measurement, a consolidation time is uncertain in the case of cohesive soils. The deformation moduli of a sand and cohesive soils were measured in different consolidation time, and the applicability of the 3t method, which have widely spread as the consolidation time, was examined in this study.
There was no effect of the consolidation time on the deformation modulus of Toyoura sand. Therefore consolidation can be terminated with the end of drainage. In the case of cohesive soils, the deformation moduli increased with the consolidation time in spite of drainage conditions and confining stresses. Their increasing gradually converged with the time.
In those kinds of experiments, the use of the 3t method as the consolidation time is impertinent because the deformation moduli determined using the 3t method are underestimated. Finally, the relationship between the consolidation time and the plasticity index was demonstrated. The result can be used for a rough index to decide a proper consolidation time.