Evaluation of Effective Strength Parameters and Micro Structural Variations of Silty Sands Stabilized with Nano Colloidal Silica

Authors

Faculty of Civil Engineering, University of Tabriz

Abstract

Saturated deposits of sands and silty sands are liquefiable during earthquakes. One of the new methods proposed for non-disruptive mitigation of liquefaction risk at developed sites is passive site stabilization. It involves slow injection of colloidal silica at the edge of a site and delivery of the stabilizer to the target location using natural groundwater flow [1]. Colloidal silica is an aqueous suspension of microscopic silica (SiO2) particles produced from saturated solutions of silicic acid [2]. The particles size can range in size from 2 to 100 nm, although the particle size is fairly constant in a given suspension. During manufacturing, colloidal silica solutions are stabilized against gelation so they can have long induction periods during which the viscosity remains fairly low up to a few months. A few studies have investigated the behavior of sands stabilized with colloidal silica. Persoff et al. measured short term strength of about 430 kPa at concentration of 20 wt% colloidal silica [3]. Gallagher and Mitchell found the baseline unconfined compressive strength ranged from 32 to 222 kPa in period of 7-30 days at sands samples treated with 5-20 wt% colloidal silica. They also did a series of cyclic triaxial tests and found that for passive site remediation, a 5 wt% concentration of colloidal silica is expected to be able to adequately mitigate the liquefaction risk of loose sands [4]. The stabilization of loose silty sand with colloidal silica has not been studied comprehensively so the present study was undertaken to investigate the unconfined compressive strength and microstructure analysis of silty sands stabilized with colloidal silica.

Keywords


[1]      Gallagher, P. M., "Passive Site Remediation for Mitigation of Liquefaction Risk", PhD Thesis, Virginia Polytechnic Institute and State University, Blacksburg, US, 2000.
[2]      Iler, R. K., "The Chemistry of Silica: Solubility, Polymerization Colloid and Surface Properties, and Biochemist Try", Wiley, New York, 1979.
[3]      Whang, J. M., "Chemical Based Barrier Materials", In Assessment of Barrier Containment Technologies for Environmental Remediation Applications, Rumer R. R., Mitchel J. K., Editors, Section 9, Springfield, VA: National Technical Information Service, US, 1995.
[4]   Yonekura, R., Miwa, M., "Fundamental Properties of Sodium Silicate Based Grout", 11th Southeast Asia Geotechnical Conference, Singapore, 4-8 May, 1993, pp 439-444.
[5]    Gallagher, P. M., Koch, A. J., "Model Testing of Passive Site Stabilization: A New Technique", 3rd International Conference on Grouting and Ground Treatment, US, 10-12 February, 2003, pp 1478-1489.
[6]    Gallagher, P. M., Finstere, S., "Physical and Numerical Model of Colloidal Silica Injection for Passive Site Stabilization", Vadose Zone Journal, 2004, 3 (3), 917-925.
[7]    Gallagher, P. M., Lin, Y., "Colloidal Silica Transport through Liquefiable Porous Media", Journal of Geotechnical and Geoenvironmental Engineering, 2009, 135 (11), 1702-1712.
[8]    Hamderi, M., "Pilot Scale Modeling of Colloidal Silica Delivery to Liquefiable Sand", PhD Thesis, Drexel University, US, 2010.
[9]    Gallagher, P. M., Pamuk, A., Abdun, T., "Stabilization of Liquefiable Soils using Colloidal Silica", Journal of Materials in Civil Engineering, 2007, 33 (1), 33-40.
[10]  Pamuk, A., Gallagher, P. M., Zimmie, T. F., "Remediation of Piled Foundations against Lateral Spreading by Passive Site Stabilization Technique", Soil Dynamic and Earthquake Engineering, 2007, 27 (9), 864-874.
[11]    Moridis, G. J., Apps, J., Persoff, P., Myer, L., Muller, S., Yen, P., Pruess, K., "A Field Test of a Waste Containment Technology using a New Generation of Injectable Barrier Liquids", Spectrum 96, Seattle, WA, 1996.
[12]    Noll, M. R., Bartlett, C., Dochat, T. M., "In Situ Permeability Reduction and Chemical Fixation using Colloidal Silica", 6th National Outdoor Action Conference, Las Vegas, NV, US, 1992, pp 443-457.
[13]   Gallagher, P. M., Conlee, C. T., Kyle, M.,"Full Scale Testing of Colloidal Silica Grouting for Mitigation of Liquefaction Risk", Geotechnical and Geoenvironmental Engineering, 2007, 133 (2), 186-196.
[14]   Hamderi, M., Gallagher, P. M., Lin, Y.,   "Numerical Model for Colloidal Silica Injected column Tests", Vadose Zone Journal, 2014, 13 (2), 138-143.
[15]    Hamderi, M., Gallagher, P. M., "An Optimization Study on the Delivery Distance of Colloidal Silica", Scientific Reserch and Essays, 2013, 8 (27), 1314-1323.
[16]   Persoff, P., Apps, J., Moridis, G., Whang, J. M., "Effect of Dilution and Contaminants on Sand Grouted with Colloidal Silica", Journal of Geotechnical and Geoenvironmental Engineering, 1999, 125 (6), 461-469.
[17]   Gallagher, P. M., Mitchell, J. K., "Influence of Colloidal Silica Grout on Liquefaction Potential and Cyclic Undrained Behavior of Loose Sand", Soil Dynamics and Earthquake Engineering, 2002, 22, 1017-1026.
[18]   Towhata, I., Kabashima, Y., "Mitigation of Seismically-Induced Deformation of Loose Sandy Foundation by Uniform Permeation Grouting", 15th International Conference of Soil Mechanics and Geotechnical Engineering, Turkey, 25 August, 2001, pp 313-318.
[19]    Diaz-Rodriguez, J. A., Antonio-Izarras, V. M., Bandini, P., Lopez-Molina, J. A., "Cyclic Strength of Natural Liquefiable Sand Stabilized with Colloidal Silica Grout", Canadian Geotechnical Journal, 2008, 45 (10), 1345-1355.
[20]    Liao, H. J., Huang, C. C., Chao, B. S.,
"Liquefaction Resistance of a Colloidal Silica Grouted Sand", Grouting and Grout and Deep Mixing Third International Conference, New Orleans, US, 2003, pp 1305-1313.
[21]   Rodriguez, J. A., Izarras V. M., "Mitigation of Liquefaction Risk Using Colloidal Silica Stabilizer", 13th World Conference on Earthquake Engineering, Canada, 1-6 August, 2004, pp 509-519.
[22]   Helland, P. E., Huang, P. H., Diffendal, R. F., "SEM Analysis of Quartz Sand Grain Surface Textures Indicates Alluvial/Colluvial Origin of the Quaternary Glacial Boulder Clays at Huangshan (Yellow Mountain), East-Central China", Quaternary Research, 1997, 48 (2), 177-186.