Analysis of an Axially and Laterally Loaded Tapered Pile in Sand

Abstract

In the soil surrounding a laterally loaded pile, there are two zones; the top plastic zone where the soil yields once the ultimate resistance is reached and the bottom elastic zone where the soil reaction is proportional to pile deflection. In this paper, an analysis is presented for an axially and laterally loaded, uniformly tapering circular pile embedded in sand, taking into account the plastic behaviour of the soil near the ground surface. The differential equations governing the pile deflection at the top plastic zone and the bottom elastic zone are transformed to non-dimensional form and solutions are obtained. Free-free and fixed-free end conditions are considered. Top deflection coefficients and maximum moment coefficients are plotted against lateral load factor for different axial load factors and taper. For given axial and lateral loads, the top deflection and the maximum moment are found to increase with taper. The fixity at the top considerably reduces the deflection at the top. A numerical problem is worked out to illustrate the use of the plots to obtain the top deflection and the maximum moment.