Experimental Investigation of the Desiccation Cracking Behavior of Soil Layers during Drying

Abstract

Desiccation cracking in drying soil is a common natural phenomenon, and it significantly impacts the soil’s mechanical and hydraulic behavior. In this study, experimental desiccation tests were conducted on an initially saturated soil layer. Several aspects of the behavior of the soil—water evaporation, volume shrinkage, crack initiation, and propagation—were investigated. By applying image processing techniques, the geometric or morphological characteristics of the crack patterns were quantitatively described. The results show that cracking occurred during the constant evaporation rate stage, when the soil was still fully saturated at a water content of 41%. A growing crack obeys certain objective laws, and it finally splits the soil surface into relatively regular patterns: The first crack generally occurs on surface defects at the bottom of “potholes” and at the fringe of aggregates. Cracks intersect with one another at right angles, and the final crack pattern is dominated by square shapes. Most cracks develop before the air entry point (w=14.5%), and surface desiccation cracking tends to terminate after the shrinkage limit (w=9.5%) is reached. In addition, this paper discusses the suction and tensile strength development involved in desiccation cracking initiation, and some explanations for various phenomena are also presented.