Mechanics of Lateral Spreading Observed in a Full-Scale Shake Test R. Dobry, M.ASCE 1 ; S. Thevanayagam, M.ASCE 2 ; C. Medina, A.M.ASCE 3 ; R. Bethapudi 4 ; A. Elgamal, M.ASCE 5 ; V. Bennett, S.M.ASCE 6 ; T. Abdoun, M.ASCE 7 ; M. Zeghal, A.M.ASCE 8 ; U. El Shamy, P.E., M.ASCE 9 ; and V. M. Mercado 10 Abstract: This paper examines in detail the mechanics of lateral spreading observed in a full-scale test of a sloping saturated fine sand deposit, representative of liquefiable, young alluvial and hydraulic fill sands in the field. The test was conducted using a 6-m tall inclined laminar box shaken at the base. At the end of shaking, nearly the whole deposit was liquefied, and the ground surface displacement had reached 32 cm. The presented analysis of lateral spreading mechanics utilizes a unique set of lateral displacement results, D H , from three independent techniques. One of these techniques—motion tracking analysis of the experiment video recording—is especially useful as it produced D H time histories for all laminar box rings and a complete picture of the lateral spreading initiation with an unprecedented degree of resolution in time and space. A systematic study of the data identifies the progressive stages of initiation and accumulation of lateral spreading, lateral spread contribution of various depth ranges and sliding zones, their relation to the simultaneous pore pressure buildup, and the soil shear strength response during sliding. DOI: 10.1061/ASCEGT.1943-5606.0000409 CE Database subject headings: Soil liquefaction; Residual strength; Hydraulic fill; Full-scale tests; Lateral displacement. Author keywords: Liquefaction; Residual strength; Hydraulic fill; Full-scale tests; Lateral displacement. Introduction Lateral spreading due to liquefaction of saturated cohesionless soils is a significant cause of damage in earthquakes, especially to foundations and buried pipes. It generally happens near water- fronts or in mildly sloping areas, with permanent lateral displace- ments of the ground surface ranging from a few centimeters to 10 m. Sometimes there is a surficial nonliquefiable layer that rides on top of the liquefiable soil as the lateral spreading develops, while in other situations—often in rivers and hence of great interest to bridge foundations—the liquefiable layer extends all the way to the ground surface. Case histories as well as experiments indicate that the effect of this ground spreading on constructed facilities is closely related to the value of permanent lateral ground surface deformation in the free field. Spatial variation in the free field also plays a role, with the ground deformation profile being of particular relevance to deep foundations. Better prediction of free field permanent defor- mation and better understanding of its mechanics are important first steps toward improved evaluation of response and perfor- mance of constructed facilities. Extensive research on this has been conducted in the last 20–30 years using a variety of research tools: compilation and study of case histories; shaking table tests at 1g and in the centrifuge; small-specimen laboratory tests; and analytical models and numerical simulations Youd and Perkins 1987; Sasaki et al. 1991; Hamada and O’Rourke 1992; O’Rourke and Hamada 1992; Dobry and Baziar 1992; Ishihara 1993; Fiegel and Kutter 1994; Dobry et al. 1995; Taboada et al. 1996; Elgamal et al. 1996, 1998; Dobry and Abdoun 1998; Okamura et al. 2001; Sharp and Dobry 2002; Abdoun et al. 2003; El Shamy and Zeghal 2006. Despite these efforts, the mechanics of lateral spreading in the free field remains poorly understood and the most reliable engineering methods for predicting lateral ground deformation remain empirical correlations or simplified analyzes calibrated with case histories e.g., Youd et al. 2002; Olson and Johnson 2008. This paper discusses results of a large-scale shake test simu- lating lateral spreading in the free field, conducted at the Univer- sity at Buffalo UB using the laminar box of Fig. 1a. Two sand 1 Institute Professor, Dept. of Civil and Environmental Engineering, Rensselaer Polytechnic Institute, 110 8th St., JEC 4049, Troy, NY 12180 corresponding author. E-mail: dobryr@rpi.edu 2 Professor, Dept. of Civil and Environmental Engineering, Univ. at Buffalo, 212 Ketter Hall, Buffalo, NY 14260. 3 Geotechnical Engineer, BGC Engineering Inc., Suite 500-1045 Howe St., Vancouver, BC, Canada, V6Z 2A9. 4 Staff Geotechnical Engineer, CH2M Hill Inc., Suite 800, 6 Hutton Center Dr., Santa Ana, CA 92707. 5 Professor, Dept. of Structural Engineering, Univ. of California, San Diego, MC-0085, La Jolla, CA 92093. 6 Research Engineer, Dept. of Civil and Environmental Engineering, Rensselaer Polytechnic Institute, 110 8th St., JEC 4049, Troy, NY 12180. 7 Iovino Chair Professor, Dept. of Civil and Environmental Engineer- ing, Rensselaer Polytechnic Institute, 110 8th St., JEC 4049, Troy, NY 12180. 8 Associate Professor, Dept. of Civil and Environmental Engineering, Rensselaer Polytechnic Institute, 110 8th St., JEC 4049, Troy, NY 12180. 9 Assistant Professor, Dept. of Environmental and Civil Engineering, Southern Methodist Univ., P.O. Box 750340 Dallas, TX 75275-0340. 10 Graduate Research Assistant, Dept. of Civil and Environmental En- gineering, Rensselaer Polytechnic Institute, 110 8th St., JEC 4049, Troy, NY 12180. Note. This manuscript was submitted on October 14, 2008; approved on June 17, 2010; published online on July 1, 2010. Discussion period open until July 1, 2011; separate discussions must be submitted for indi- vidual papers. This paper is part of the Journal of Geotechnical and Geoenvironmental Engineering, Vol. 137, No. 2, February 1, 2011. ©ASCE, ISSN 1090-0241/2011/2-115–129/$25.00. JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING © ASCE / FEBRUARY 2011 / 115 Downloaded 08 Feb 2011 to 118.97.186.66. Redistribution subject to ASCE license or copyright. Visit http://www.ascelibrary.org