Journal of Earth Science & Climatic Change
Open Access

Abstract

The formation of cracks on soil surface is a common natural phenomenon as the soil is subjected to drought climate. The presence of cracks can significantly affect soil performance in various geological, geotechnical, and environmental engineering applications, and decrease the stability of earth structures. With increasing frequency of severe drought climate, better understanding of soil response and cracking failure process is becoming an increasing significant issue. In this investigation, a series of desiccation tests were performed on soils by simulating long term drought climate. The soil water evaporation, volumetric shrinkage and surface cracking processes were monitored and their coupled mechanisms were thoroughly analysed. Moreover, the evolution of mechanical parameters that controlling soil cracking development was measured during drying. It is found that the evaporation process of soil is composited of three stages: Constant, falling and residual rate zones. The soil is saturated during constant rate period. The shrinkage process of soil is also composited of three stages: Normal, residual and zero shrinkage. The initiation and propagation of desiccation cracks show evident dynamic characteristics and significantly depend on soil water evaporation rate, stress state and shrinkage properties of soil. The cracks initiate as the tensile stress induced by suction exceeds soil tensile strength, and the corresponding evaporation rate lies in constant stage where the soil is still saturated. Most of the cracks develop during constant evaporation rate period and normal shrinkage stage. Intrinsically, the crack opening is the result of pore volume shrinkage, and the cracking curve presents the same physical significance with the shrinkage curve. Based on the obtained results, a tensile failure criterion is proposed for predicting soil cracking behaviour as the soil is subjected to drought climate.

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