Consolidation analysis of inhomogeneous soil subjected to varied loading under impeded drainage based on the spectral method

Abstract

The consolidation behaviour of soft clays is significantly influenced by loading patterns, soil inhomogeneity, and boundary drainage conditions. Despite their significance, a notable gap exists in the availability of rigorous analytical solutions capable of integrating these factors into the consolidation analysis of inhomogeneous soft clay. This paper presents a comprehensive analysis of the consolidation behaviour of inhomogeneous soft clay subjected to impeded drainage conditions under time-dependent loading. The study employs the spectral method to derive solutions for specific distributions of inhomogeneous soil property distributions and loading patterns. The accuracy of the proposed method is validated through comparisons with previous analytical solutions, finite element method (FEM) solutions, laboratory tests and case studies, demonstrating improved predictive capabilities. A parametric study based on the proposed solution indicates that the dimensionless factors related to drainage capacity (Rt and Rb) adversely impact soil consolidation, with smaller values leading to increased divergence from calculations assuming fully pervious conditions. Notably, solutions assuming fully pervious conditions can maintain considerable accuracy within a 5% error range only when Rt and Rb exceed a certain threshold (e.g., Rt > Rb /(0.049Rb − 0.426) in this study). Otherwise, impeded drainage conditions must be considered for accurate consolidation calculations.