Postcyclic Reconsolidation Strains in Low-Plastic Fraser River Silt due to Dissipation of Excess Pore-Water Pressures

Abstract

The postcyclic reconsolidation response of low-plastic Fraser River silt was examined using laboratory direct simple shear testing. Specimens of undisturbed and reconstituted natural low-plastic Fraser River silt and reconstituted quartz powder, initially subjected to constant-volume cyclic loading under different cyclic stress ratios (CSRs) and then reconsolidated to their initial effective stresses ( σ vo ′ ) , were specifically investigated. The volumetric strains during postcyclic reconsolidation ( ev-ps ) were noted to generally increase with the maximum cyclic excess pore-water pressure ( Δ umax ) and maximum cyclic shear strain experienced by the specimens during cyclic loading. The values of ev-ps and maximum cyclic excess pore-water pressure ratio ( ru-max ) were observed to form a coherent relationship regardless of overconsolidation effects, particle fabric, and initial (precyclic) void ratio of the soil. The specimens with high ru-max suffered significantly higher postcyclic reconsolidation st...