Effect of pile connections on the performance of the nailed slab system on the expansive soil

Abstract

Expansive soils are clay that swells and shrinks with changing moisture content. The pavement that constructed on these soils is subjected to large uplifting forces caused by swelling. Hence, there is an imperative need to counteract the problem posed by these soils by devising innovative pavement technique. An attempt to develop a simple, easy to install and cost-effective alternative pavement system, nailed slab system was developed, wherein slab pavement will be connected to a reinforced concrete mini piles.This research examines the emerging role of mini piles in the context of reducing soil uplift movement and the nailed slab system (pile supporting slab pavement) a system for minimizing slab movement due to swelling in expansive soil by conducting small-scale experimental modeling in laboratories. The heave prediction also doing by using the correlation between change in moisture content and vertical strain from oedometer test data. The results of this study indicate that reinforcing the soil by using the mini piles can reduce heave of soil, and the nailed slab system experiencing smaller upward movement than an unsupported slab. The connection between the pile and the slab has a significant effect on the system's ability to withstand the upward movement of expansive soil. When pile and the slab were monolithically connected, the system shows the better performance than those the slabs with the free head pile. Thereafter a heave prediction analysis provided the amount of heave that slightly overestimates, but still good enough for a rough estimation.