Soft soils improvement by granular piles reinforced with horizontal geogrid strips

摘要

The present paper investigates the effect of geogrid, as horizontal strips, on the ultimate load intensity and bulging of floating as well as end bearing granular piles. The laboratory model tests and numerical analyses have been carried out on unreinforced and granular piles reinforced with horizontal geogrid strips embedded in very soft clay. The short-term and displacement controlled laboratory model tests were carried out based on unit cell concept. Numerical analysis has been extended to study the influence of shear strength of clay, number and stiffness of geogrid strips on the granular piles. The results of laboratory model tests in the form of load-settlement relationship were compared with those obtained from FEM software, PLAXIS 3D. The ultimate load intensity for unreinforced floating and end bearing granular piles treated ground has been increased by 185 and 238% as compared to untreated ground. The ultimate load intensity for 25, 50 and 70 mm c/c spaced floating granular piles reinforced with horizontal strips-treated ground increased by 442, 396 and 316% as compared to untreated ground. The results indicated significant improvement in the ultimate load intensity and reduction in bulging of granular piles by incorporating geogrid strips.