Effect of Cavities on the Behaviour of Model Pile under Axial Loading in Sand

Abstract

Presence of cavities in soils is an important area of interest within the field of geotechnical engineering. A better understanding of the behaviour of such soils, particularly in locations where the presence of gypsum deposits is apparent, will have a large impact on the stability of foundations and allows designers and engineers to have a convincing explanation of this phenomenon on the stability of foundations in general. The research offers an experimental investigation to study the performance of axially loaded piles embedded in sandy soils with cavities. The experimental study comprised a full laboratory testing programme carried out on small scale piles embedded in predetermined cavities within a soil mass. The experimental model has the capability to investigate the effect of different cavity locations on the ultimate pile resistances. Thirteen cavity locations were chosen to study their influence on the ultimate carrying load of single pile. It was concluded that the maximum ultimate carrying load of the pile is reduced by the presence of the cavity within the soil mass. This reduction varies according to the cavity location. The effect of cavity’s presence on the ultimate bearing capacity of pile ranged from 0% to 30.82% for side cavities, while the range of reduction factor for cavities under the pile tip is from 31.58% to 43.4%. The reduction in pile capacity increases when the cavity is closer to the pile. Also, pile settlement value without cavity is less than the settlement of the same pile with cavity.