Analytical solution to consolidation of accreting soil considering step load and horizontal drainage layers

Accreting soil system with horizontal drainage layers (HDLs) widely exists in engineering practices. With the existence of HDLs, each soil layer undergoes two stages: layer formation stage and surcharge loading stage. The methods proposed by Gibson and Zheng et al. are adopted to derive the analytical solution for the layer formation stage, while the separation of variables method and Duhamel's principle are combined to develop that for the surcharge loading stage. The solution is verified against two existing analytical solutions and a numerical model. Parametric studies are then conducted to investigate the consolidation characteristics. Given a certain design height of accreting soil system, an upper limit of the maximum excess pore-water pressure (ULMP) is observed with HDLs if consolidation coefficient is large enough or accreting rate is small enough. When ignoring the interlayer formation interval, ULMP is inversely proportional to the consolidation coefficient and proportional to the accreting rate and the square of layer thickness. A prediction method for the time when ULMP appears is provided considering the influence of accreting rate, layer thickness, and consolidation coefficient. A design chart for reference value of the maximum layer thickness is also proposed.

Automated summary

This study investigates the accreting soil system with horizontal drainage layers in engineering practices, deriving analytical solutions for different stages and conducting parametric studies to investigate consolidation characteristics. A prediction method for the appearance of maximum excess pore-water pressure is provided, along with a design chart for reference value of the maximum layer thickness.