Combined Vertical and Radial Consolidation under Time-Dependent Loading

Abstract

Combined vertical and radial consolidation drainage under linear time-dependent loading is presented with varying loading-dependent coefficients of vertical and radial consolidation determined analytically and experimentally. The convolution integral of viscoelasticity theory with variable time was first used to separately predict the average degree of consolidation under time-dependent loading for individual vertical and radial directions. The predicted average degree of combined vertical and radial consolidation was then determined using Carrillo's approach. Four different loading rates were applied in consolidation tests on three types of remolded clay with various plasticity indices to estimate the effects of loading rate on the consolidation settlement. Furthermore, two different spacing ratios of well drain were investigated. The findings indicated that Carrillo's approach for the present three-dimensional consolidation is valid. Furthermore, the viscoelastic settlement prediction in terms of the average degree of consolidation using loading-dependent coefficients of vertical and radial consolidation was more consistent with the experimental results compared with those assuming a constant coefficient of consolidation in the vertical and radial directions. Moreover, specimens with a lower spacing ratio showed a higher average degree of consolidation compared with those with a higher spacing ratio because of the shorter radial drainage path.