Semianalytical Solution for Consolidation of Reclaimed Land with Horizontal Drains

Abstract

In land reclamation projects, the scheme of dredged clays with a multiplicity of horizontal drains is often adopted to shorten the vertical drainage path for seepage flow of pore water, but studies of consolidation theory on layered clay–sand reclamation are relatively inadequate. In this investigation, a novel semianalytical solution is obtained, applying the boundary transform technique based on the plane-strain consolidation theory. The correctness of the presented solution is investigated by comparing against results obtained from finite-element analyses and field tests. Subsequently, a detailed parametric analysis is conducted to explain how the consolidation efficiency is affected by geometric and physical parameters of soft soils and horizontal drains. It is revealed that the rate of consolidation increases with the horizontal permeability of dredged clay but decreases with the width of reclaimed land. For the effect of horizontal drains, the consolidation efficiency increases with the thickness, horizontal permeability coefficient, and layout number. Moreover, the optimal design method of layered horizontal drains is described in detail, and a figure considering the optimal thickness, layout number, and position of horizontal drains is provided as theoretical guidance for use in design.