Geotechnical applications of chemically enhanced drainage

Abstract

SummaryThe paper explores application of the engineered increase in soil permeability, achieved using reaction of guanidinium solutions with smectite soils, to geotechnical problems. The comparison between the finite element analysis of the enhanced permeability model for axisymmetric conditions and a simplified analytical solution demonstrates the importance of accounting for diffusive and dispersive fluxes. In order to illustrate possible practical application of the proposed soil improvement technique, two geotechnical examples have been numerically explored: improving performance of a ground water well and the stabilization of a slope by chemically enhanced drainage. For the well application, it has been demonstrated that for a relatively small degree of treatment, the power consumption can be reduced to a half, compared with the non‐treated soil. For the slope stability application, the water table downstream of the drain can be significantly lowered using moderate pump/collector pressures at the centre of the drain, causing a higher increase in the factor of safety for a larger area subjected to the chemically enhanced drainage. The particularly promising result is that in both applications the largest gain in the well/drain efficiency has been observed for smaller chemically enhanced areas, where a short duration of treatment and small amounts of chemicals decrease the power consumption and increase the safety factor at the highest rate. Copyright © 2017 John Wiley & Sons, Ltd.