Load-Settlement Response of Geotextile Encased Laterally Reinforced Granular Piles in Expansive Soil Under Compression

Abstract

Expansive soils are prone to volumetric changes when interacted with water, which makes them unfavorable in civil engineers’ perspective. Granular piles are the effective and economic ground improvement techniques available under such criteria. As granular piles attain their support from surrounding soil, these generally fail by bulging under compression in soft clays. This limitation can be answered by provision of tubular geotextile encasement around the column. However, when the compressive loads are high, the bulging in granular pile makes the geotextile reach its tensile strength and does not provide any additional improvement. Further, this problem can be solved by providing lateral reinforcement in the column, as it tends to reduce the stress concentration at the top portion of the pile where bulging occurs, improving their performance. The present study deals with the response of granular piles in the presence of encasement and combination of encasement and lateral reinforcement under strain-restricted compression tests. In both floating and end-bearing granular piles, the load capacity of composite soil is substantially increased. The rate of increase in load-carrying capacity was higher when end-bearing granular pile was reinforced with geotextile encasement and minimal with additional lateral reinforcement. The results show that geotextile encased laterally reinforced granular piles of end-bearing type and floating type showed a substantial increase in load-carrying capacity relative to clay by 2.44 and 2.01 times, respectively.