Determination of Flow Properties & Microstructure of Cemented & Fibre Amended Toyoura Sand

Colin Schmidt, Tim Newson

In the proceedings of: GeoRegina 2014: 67th Canadian Geotechnical Conference

Session: Engineering Geology and Rock Mechanics

ABSTRACT: This study reports on a joint research initiative between Western University and the University of Fukuoka on cement solidification of sand and silt soil found in the Tokyo Bay region of Japan. This material an environmentally friendly option for reducing the impact of earthquakes and producing very stable construction soils. The technique also includes the addition of short, recycled PVA fibres to reduce shear deformations of geotechnical structures. Toyoura sand and silica flour were used as soil samples, with Ordinary Portland Cement as the solidifying material. This paper focuses primarily on the 1D consolidation and flow properties of these soil mixes, and links their behavior to the microstructure observed in CT and SEM scans. RÉSUMÉ Cette étude rend compte d'une initiative de recherche conjointe entre l'Université Western et l'Université de Fukuoka sur le ciment solidification du sable et de terre de limon trouvé dans la région de la baie de Tokyo au Japon. Ce matériau une option écologique pour réduire l'impact des tremblements de terre et la production de sols de construction très stables. La technique comprend aussi l'ajout de fibres courtes de PVA recyclés afin de réduire les déformations de cisaillement des structures géotechniques. Toyoura sable et farine de silice ont été utilisés comme échantillons de sol, avec du ciment Portland ordinaire comme le matériau de solidification. Ce document se concentre principalement sur la consolidation et les propriétés d'écoulement 1D de ces mélanges de terre, et relie leur comportement à la microstructure observée en CT et SEM scans. 1 INTRODUCTION After the magnitude 9.0 Great East Japan Earthquake of March 2011, 30-50% of buildings in the eastern coastal cities of Japan were damaged due to soil liquefaction in the form of slope failures, sand boils and excessive settlements (Yasuda, Harada, Ishikawa, & Kanemaru, 2012). Urayasu City, off the coast of Tokyo Bay, was one of the hardest hit regions of the country and saw nearly 85% of the coastal soil liquefy as shown in Figure 1. Nearly 25 million tons of debris has been cleared away since 2011, much of which has been recycled or reused in engineering works including stabilization of liquefiable soils. This included a significant amount of gypsum plasterboard and bamboo fibres from local buildings. This project, a long term collaboration between Western University and Fukuoka University, focuses on the addition of ordinary Portland cement (OPC) and PVA fibres as stabilizers in silty sands around the Tokyo Bay region. Though stabilization of an entire coastline against earthquake loading is an ambitious project, smaller projects that experience dynamic loads, such as high traffic roadways and train tracks, also allow this concept to be more economically feasible and provide opportunities to use significant amounts of waste material. To initiate such civil works, the engineering properties of the reinforced silty sands must be acquired through laboratory and in-situ testing techniques. The purpose of this paper is to evaluate the microstructure, consolidation parameters, and flow properties of silty and clean Toyoura sand stabilized with commonly found waste materials. Soil has been examined through microscopic imagery and CT scans to determine how the addition of fibres and cement alter the skeletal structure and affect the drainage properties. Quantitatively, the pore volume, initial void ratio and compressibility of a sample has been determined to estimate permeability. A link between the qualitative and quantitative has been created when this data was combined. 2 BACKGROUND The effects of static and dynamic loading on sand with and without non-plastic silts has been reasonably well documented over the past several decades (Chiaro, Koseki, & Sato, 2012; Jafarzadeh & Sadeghi, 2012; Askari, Dabiri, Shafiee, & Jafari, 2011; Yang, Savidis, & Roemer, 2004; Xenaki & Athanasopolous, 2003; Salgado, Bandini, & Karim, 2000; Hyodo, Tanimizu, & Yasufuku, 1994). Further works have been published on stabilization materials such as OPC, fly ash, PVA fibres, coir fibres, fibreglass, natural reed, palmyra, Buna-N rubber fibres and carpet waste fibres for various sands and sandy soils (Nakamichi & Sato, 2010; Consoli, Bassani, & Festugato, 2010; Rao & Rao, 2007; Chen, 2006; Dano, Hicher, & Tailliez, 2004; Kaniraj & Havanagi, 2001; Gray, 1988; Gray & Maher, 1989; Carrier, 2003). What has yet to be studied in depth is the correlation between the microstructure of OPC and PVA fibre amended silty sand mixtures and their permeability and flow properties.

RÉSUMÉ: mination of Flow Properties & Microstructure

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Cite this article:
Colin Schmidt; Tim Newson (2014) Determination of Flow Properties & Microstructure of Cemented & Fibre Amended Toyoura Sand in GEO2014. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GeoRegina14Paper478,author = Colin Schmidt; Tim Newson,title = Determination of Flow Properties & Microstructure of Cemented & Fibre Amended Toyoura Sand,year = 2014}