Effect of Wetting and Drying Cycles on Swell/Collapse Behavior and Cracks of Fine – Grained Soils

Abstract

Many of the soils undergo volumetric changes due to the change in the water content. Swell-shrink and collapse behavior of those soils affects the stress state in soil and the interacted structures. Shrinkage in the soil produce cracks of different patterns, and affects the swelling potential in next wetting cycle.This study covers swelling and collapsing properties of four different soils from Mosul city. The changes in swelling and collapsing properties with respect to number of wetting and drying cycles have been investigated. Also, A shrinkage cracks have been studied with aid of digital image after each drying cycle. Number of segments and area of cracks calculated with aid of AutoCAD package.Results indicated that, the collapse potential is influenced by soil type (soil composition) and applied loads. As the applied loads increase the collapse potential increases. For sandy soil the collapse potential decreased with increasing wetting and drying cycles, and for the clayey soils, swell potential decreased while collapse potential increased with these cycles. It has been shown that the cracks increase with wetting-drying cycles. Larger values of percent crack area to the initial sample area has been observed in the soil that contain more clay content than other types of soils.