Permeation potential of colloidal silica for passive stabilization of liquefiable soils

Abstract

Passive stabilization is a new ground improvement technique against liquefaction. It consists of the low pressure injection of colloidal silica in the pores of a liquefiable soil. After well-controlled time, colloidal silica becomes a firm gel and changes the mechanical properties of the soil, making it less vulnerable to strain accumulation and strength degradation related to liquefaction. The effectiveness of the technique relies greatly on the ability to inject (or permeate) the colloidal silica into the soil, well before its gelation. This paper first investigates experimentally the factors affecting the permeation of colloidal silica, via ID permeation tests in granular soil columns. Then, a simple analytical tool is proposed for estimating the (time-variable) flow rate of colloidal silica through the soil, which is based on Darcy's law after adjustments for the differences in viscosity and density of colloidal silica as compared to that of water. The predictions with this tool agree well with the measurements of the ID permeation tests. © The authors and ICE Publishing: All rights reserved, 2015.