Analysis of heave behaviour of expansive soil provided with granular pile anchors using plaxis

Abstract

The majority of the lightly loaded structures built on expansive soils exhibits swelling behaviour with varying moisture content. To nullify this effect, numerous remedial techniques are evolved. Granular Pile Anchor Foundation (GPAF) is one among the innovative short tensile pile technique that can be promisingly suggested as a foundation method in expansive soil. GPAF traces its origin from the discrete granular pile, which is widely used in soft clays and loose sand. Problems for the foundation in expansive soil are uplift. Hence, the granular piles are provided with anchor rod centrally, which anchors the footing to the anchor plate placed at the bottom. In the year 2006, a research was carried out to study the heave control behaviour of granular pile anchor for footing resting on expansive soil. Outcomes of the research proved the efficacy of GPA over concrete piles. In present work, numerical simulation of the previous field study was made to analyse the heave control phenomena of granular pile anchor using Plaxis 2D, an analysis software based on the finite element method. Performance of Granular Pile Anchor in numerical analysis agrees with that of field test outcomes. Heave control phenomena of Granular Pile Anchor is better than that of concrete piles. This is mainly due to the thorough interlocking of rough-surfaced granular pile material at the interface which is absent in case of concrete pile. Heave of footings is decreasing with increase in length and diameter of the piles used to anchor the footings. The heave values obtained using Plaxis are greater than that from field experiments. This may be due to the empirical assumption of material properties used in the input.