An Experimental Study on Improving the Performance of Silty Soil by Encased Granular Column Using Shredded Tire Chips

Abstract

Use of stone/granular columns is considered as one of the influential soil-stabilizing methods that can increase the load bearing capacity of soft soil foundations considerably. Recently, it has been reported that the stone aggregate can be replaced by shredded tire chips partially or fully, which will lead to an economical design solution for a granular column. On the other hand, the tire chips are waste materials, and if used for major geotechnical applications, this will not only solve the environmental problems but also result in considerable savings in terms of natural resources thus making the construction method sustainable. This paper presents the results of an experimental study carried out with shredded waste tire chips as a substitute fornatural aggregates and also their effect on granular column behavior. Typical size ranges of tire chips used in the study were 10 mm × 10 mm × 10 mm. The aggregates used were passing through 12.5 mm and retained on 10 mm sieve. Geogrid encasement, namely combi-grid, was used in experimental investigation. A series of small-scale model tests was performed on ordinary granular column (OGC) as well as granular columns made up of shredded tire chips and aggregates and encased with combi-grid (EGC). All the granular materials were compacted at 90% relative density. The strain rate for all the tests were maintained at 1.2 mm/min. The results of the study indicate that the load-carrying capacity significantly increased even the granular column made of 100% tire chips. It has also been observed that ordinary stone column made of aggregates without encasement can be completely replaced by the encased granular column made of 100% tire chips. However, the load-carrying capacity of encased stone column made of aggregates found to be higher than that of tire chips.