Shaking table studies on geosynthetic reinforced soil slopes G. Madhavi Latha* and A. M. Nandhi Varman This paper describes shaking table model studies conducted on unreinforced and reinforced soil slopes. A computer controlled hydraulically driven single degree of freedom shake table was used in these tests. Model soil slopes were constructed using clayey sand (SC) in a laminar box. Two different slope angles were used in tests. Two different types of reinforcement, namely, a woven geotextile and a biaxial geogrid were used in the tests. The models were instrumented with ultrasonic displacement transducers and accelerometers at different locations. The slopes were subjected to horizontal base shaking of known acceleration and frequency and the displacement and acceleration were monitored for time increments. Comparison of displacement and acceleration of tests with different slope angles and with reinforcing layers of different stiffness values resulted in some important observations regarding the response of these soil slopes under seismic shaking conditions. Tensile stiffness of the reinforcement plays an important role in controlling the seismic deformations and the beneficial effects of reinforcement are more pronounced in flatter slopes. Acceleration amplifications did not alter with the inclusion of reinforcing layers in the model studies reported in this paper because of the dimensional limitations. Numerical modeling of the geosynthetic reinforced soil slopes subjected to base shaking is also presented and the models are verified with the experimental results. Keywords: Geosynthetics, Soil slope, Model tests, Shaking table, Reinforcement, Finite element analysis This paper is part of a special issue on geosynthetics Introduction Soil reinforcement to improve the performance of slopes by reducing deformations and to build steep slopes in less space has been a potential topic of interest for geotechnical engineers in recent times. Static stability of reinforced soil slopes has been well investigated by several researchers. Soil slopes that are quite stable under static conditions can simply collapse during earthquakes due to several reasons, including ground shaking leading to excessive vibrations and deforma- tions, loss of bearing strength of the foundation soil due to liquefaction, and reduction in the safety factor of the slope due to transient shooting up of the pore water pressures. Understanding the role of reinforcement in stabilizing the soil slopes subjected to seismic shaking is very important in this context to design safe slopes in seismically active zones. A good amount of literature is available on the seismic response of reinforced soil slopes (Perez, 1999; Perez and Holtz, 2004; Lo Grasso et al., 2005; Nova-Roessig and Sitar, 2006; Huang et al., 2008). Model studies on shaking table have provided valuable insight into liquefaction, post- earthquake settlement, foundation response, soil-structure interaction, and lateral earth pressure problems (Kramer, 1996). Wood et al. (2002) discussed a number of issues associated with the use of shaking tables for geotechnical earthquake engineering, concentrating in particular on the application of scaling and modeling laws, the development of containers for testing geotechnical systems, and the control of seismic motions. Shaking table tests are 1-g model tests. Iai (1989) derived a similitude for the shaking table tests on saturated soil–structure–fluid model in 1-g gravitational field. Shaking table tests facilitate testing of relatively larger structures and model response can be physically observed in these tests along with measurements of response parameters. Latha and Krishna (2008) demonstrated the use of shaking table studies for understanding the seismic response of geosynthetic reinforced soil walls. Lin and Wang (2006) performed a series of large-scale shaking table tests to understand the dynamic response and behavior of slopes. Seismic response of small scale nailed soil slopes is studied through shaking table studies by Giri and Sengupta (2009). Large-scale shaking table Department of Civil Engineering, Indian Institute of Science, Bangalore 560012, India *Corresponding author, email madhavi@civil.iisc.ernet.in ß 2014 W. S. Maney & Son Ltd Received 27 September 2013; accepted 10 January 2014 DOI 10.1179/1939787914Y.0000000043 International Journal of Geotechnical Engineering 2014 VOL 8 NO 3 299