Influence of Micropiles on the Bearing Capacity of a Layered Soil System—A Numerical Study

Abstract

This paper studies the effect of micropiles embedded below the foundation resting on layered soil. The foundation soil consists of two soil layers: the top layer of dense sand and the bottom layer of soft clay. A 2D finite element software, GeoStudio has been used to generate a model of dimension 1.2 m wide and 0.9 m deep. The numerical model has been reinforced by two rows of micropiles one on either side of the square footing. The thickness of the topsoil layer has been varied as 0.15, 0.2, 0.25 and 0.3 m, and for each case, the influence of the micropiles over the soil bearing capacity has been studied. The results have been extracted in the form of stress versus settlement plots for both reinforced and unreinforced cases. The axial resistance of the micropiles has also been analysed in the study. On the basis of results, it has been concluded that the bearing capacity of the footing has further improved for an increase of micropile length embedded in the dense sand. The maximum improvement in the bearing capacity has been found as 31% for 0.3 m of thickness of dense sand. Axial resistance of the micropiles also increased with increase in the thickness of dense sand. The micropiles have a maximum axial resistance of 20% at the top section of the micropile.