POROSITY ASSESSMENT IN ONE-DIMENSIONAL PERMEATION GROUTING USING SUSPENSION-TYPE GROUT SOLUTION

Abstract

Soil liquefaction, triggered by seismic activity, destabilizes loose and saturated ground leading to extensive damage. This research explores the application of permeation grouting as a mitigation technique for liquefaction. Grouting is a ground improvement technique that involves injecting grout solutions at low pressures into soil pores to enhance its properties. To promote sustainability, alternative materials to conventional cement-based grouts were proposed and demonstrated to be viable. Suspension-type grouts densify and solidify the ground, offering higher performance compared to solution-type grouts. However, a limitation of suspension-type grouts is the occurrence of clogging. As permeation progresses, porosity of the soil reduces, along with the performance of grouting. To evaluate the flow behavior and interaction of the grout to the soil, one-dimensional permeation tests using varying grout concentrations were conducted. The relationship between permeation pressure, permeation volume, and porosity of the soil was analyzed. Results demonstrated that densification happens as permeation volume and pressure increases. While beneficial for increasing liquefaction resistance, immediate densification impedes further grout permeation, reducing the improvement radius. Therefore, porosity assessment is critical in balancing densification and permeation volume. Numerical estimation using Kozeny-Carman equation was employed to model the porosity changes during permeation, and mean particle size was found to be a crucial parameter in the accuracy of the porosity estimation.