American Society of Civil Engineers


Stabilization of Liquefiable Soils Using Colloidal Silica Grout


by Patricia M. Gallagher, (corresponding author), A.M.ASCE, (Asst. Prof., Dept. of Civ., Architectural, and Envir. Engrg., Drexel Univ., 3141 Chestnut St., Philadelphia, PA 19104 E-mail: pmg24@drexel.edu), Ahmet Pamuk, (Postdoctoral Res. Fellow, Dept. of Civ. Engrg. and Engrg. Mech., Columbia Univ., 610 Mudd, 500 West 120th St., New York, NY 10027), and Tarek Abdoun, A.M.ASCE, (Asst. Prof. and Mgr., RPI Geotech. Centrifuge Res. Ctr., Dept. of Civ. Engrg., Rensselaer Polytechnic Inst., JEC 4049, Troy, NY 12180-3590)

Journal of Materials in Civil Engineering, Vol. 19, No. 1, January 2007, pp. 33-40, (doi:  http://dx.doi.org/10.1061/(ASCE)0899-1561(2007)19:1(33))

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Document type: Journal Paper
Abstract: Passive site stabilization is a new technology proposed for nondisruptive mitigation of liquefaction risk at developed sites susceptible to liquefaction. It is based on the concept of slowly injecting colloidal silica at the edge of a site with subsequent delivery to the target location using natural or augmented groundwater flow. Colloidal silica is an aqueous dispersion of silica nanoparticles that can be made to gel by adjusting the pH or salt concentration of the dispersion. It stabilizes liquefiable soils by cementing individual grains together in addition to reducing the hydraulic conductivity of the formation. Centrifuge modeling was used to investigate the effect of colloidal silica treatment on the liquefaction and deformation resistance of loose, liquefiable sands during centrifuge in-flight shaking. Loose sand was successfully saturated with colloidal silica grout and subsequently subjected to two shaking events to evaluate the response of the treated sand layer. The treated soil did not liquefy during either shaking event. In addition, a box model was used to investigate the ability to uniformly deliver colloidal silica to loose sands using low-head injection wells. Five injection and two extraction wells were used to deliver stabilizer in a fairly uniform pattern to the loose sand formation. The results of the box model testing will be used to design future centrifuge model tests modeling other delivery methods of the grout.


ASCE Subject Headings:
Colloids
Grouting
Soil liquefaction
Soil stabilization