Indian Geotechnical Conference IGC2016 15-17 December 2016, IIT Madras, Chennai, India 1 BEARING CAPACITY OF CIRCULAR FOOTING ON GEOGRID- REINFORCED GRANULATED BLAST FURNACE SLAG Dr. Laxmikant Yadu 1 Pankaj 2 1 Assistant Professor, 2 Research Scholar (PhD), Department of Civil Engineering, National Institute of Technology, Raipur, Chhattisgarh – 492001. E-mail address: 1 lkyadu.ce@nitrr.ac.in, lkyadu@gmail.com, 2 pankajbajaj522@gmail.com Dr. R.K.Tripathi Professor, Department of Civil Engineering, National Institute of Technology, Raipur, Chhattisgarh – 492001. E-mail address: rajesh_tripathi64@yahoo.co.in ABSTRACT: Granulated blast Furnace slag (GBS) is a by-product of iron/steel industries. GBS has good potential to be used as granular material in place of conventional granular materials i.e. sand and aggregate. It can be used as structural fill in low laying areas. In such cases, it is required to evaluate the bearing capacity of the fill. Many times, it is required to reinforce the fill with some suitable reinforcing materials to enhance the bearing capacity. In the present study, response of circular footing has been studied by using GBS as fill material and geogrid as reinforcing material. Various geometric parameters affect the bearing capacity of reinforced fill. Geometric parameters i.e. top layer spacing of geogrid from the bottom of the footing have been considered to get the response of circular footing resting of geogrid reinforced GBS fill. Parametric study has been done to find optimum geometric parameter for getting the maximum benefit in terms of increase in bearing capacity out of the geogrid. Further, numerical simulation has been done to compare the experimental results with numerical results. Numerical simulation shows reasonable match with experimental results. Keywords: Fly ash, slope, Stabilized soil. 1 Introduction In recent years the use of various waste products in civil engineering construction has gained considerable attention in view of the shortage and high costs of suitable conventional aggregates, the increasing cost of waste disposal and environment constraints. It is observed from literature that natural sand has been used as a granular fill material (Kumar and Saran 2001; Shin et al. 2002; Shitaram and Sireesh 2005; Dash et al. 2001, 2003, 2004; Patra et al. 2005; Kumar et al. 2007). Scarcity of natural sand leads to use of alternate materials as a granular fill material. Granulated blast furnace slag (GBS) is a non-metallic by-product produced in the process of iron making in a blast furnace and is being used in various civil engineering works. India produces around 11 million tones of slag every year, so it may be beneficial to use GBS as a granular material. Various researchers, Huang and Tatsuoka 1990, Akinmusuru and Akinbolade 1981, Guido et al. 1985, 1986 have conducted experiments to improve bearing capacity of granular fill by using various products i.e. metal bars, rope fibers, geotextiles. In this study GBS has been used as a granular fill material and geogrid is used as reinforcement for improving its bearing capacity. 2 Materials used and Experimental program 2.1 GBS The GBS was procured from Bhilai Steel Plant, Bhilai. Chhatttisgarh, India. The physical properties of GBS used for the experiment are tabulated in Table 1. 2.2 Geogrid A geogrid is a geosynthetic material used to reinforce soils and similar materials. The tensile strength of used geogrid at 2% elongation was 6 kN/m. 2.3 Experimental Program The apparatus for conducting the tests is cylindrical in shape having 31.5 cm height and 38.5 cm diameter and is shown in Figure 1. The GBS is filled in 4 layers up to a height of 20 cm. Thickness of each layer was equal to 5 cm. Each layer was filled by pouring the sample from a height of 62 cm. A plate of 10 cm diameter (D) and 1.2 cm thick was used as a footing. The