Drought‐Induced Soil Desiccation Cracking Behavior With Consideration of Basal Friction and Layer Thickness

Abstract

Drought‐induced cracking of soils is of great concern with the advent of global climate change. The cracking process accelerates the evaporation rate of pore water, lowers the water retention capacity, and degrades the hydraulic‐mechanical properties of soils. Basal friction and layer thickness are two important aspects affecting the subsurface cracking. To explore their detailed effects on soils under drying, we conduct a series of desiccation tests on twelve slurry soil bars and select four types of base materials with different roughness levels and three kinds of layer thicknesses. We track the dynamic cracking process in various samples and adopt the noncontact optical technique—digital image correlation—for the motion of soil particles. Experimental results validate that the coupled effects of basal conditions and soil layer thickness play a key role in governing the soil cracking behavior. The presence of rough bottom surface induces the onset and propagation of desiccation cracks at both top and bottom surfaces. Some of the cracks initiated at the bottom do not propagate through the soil profile. Increasing layer thickness weakens the effect of basal friction on the soil top surface shrinkage but increases the frictional force acting on the base and results in more crack initiations at the bottom. The digital image correlation results further reveal that cracks initiated on the bottom surface and propagated upward vertically are dominated by tensile stresses, while those propagated upward obliquely are dominated by the joint action of shear and tensile stresses.

Investigating Soil Desiccation Cracking Using an Infrared Thermal Imaging Technique

“…The modellings revealed that individual crack propagation depends on the stress/strain concentration in local soil bodies (Lin et al., 2021; Pouya et al., 2019; Sánchez et al., 2014). This outcome was further confirmed in soil desiccation experiments at the laboratory scale, where the progression of individual crack branches was traced using precise image analysis techniques such as Digital Image Correlation (DIC) and Particle Image Velocimetry (PIV) (Li et al., 2019; Trabelsi et al., 2018; Wang et al., 2018; Wei et al., 2016; Zeng et al., 2020). It should be pointed out that the hydro‐mechanical coupled process along soil desiccation cracking is complicated, considering the interaction among pore water evaporation and migration, solid particle motion and internal stress evolution (Chertkov & Ravina, 2001, 2002; Costa et al., 2013; Kodikara & Costa, 2013; Li et al., 2011, 2019; Lin et al., 2021; Péron et al., 2009; Pouya et al., 2019; Sánchez et al., 2014; Shin & Santamarina, 2011; Shorlin et al., 2000; Toga & Alaca, 2006).…”

“…Consequently, there are limitations in understanding how internal cracks develop inside the entire soil, using the infrared thermal imaging technique only. For example, Zeng et al (2020) highlighted that the boundary effect between horizontal soil layers along the vertical direction could mobilize many cracks forming at the bottom of the overlying soil under evaporation and progressing toward the surface. To monitor the development of these cracks and understand their governing mechanisms, investigations need to apply other methods such as noninvasive techniques (e.g., X-ray CT) or embedded sensing elements in soils (e.g., distributed optical fiber sensing technique).…”

Modeling of Drying‐Induced Soil Curling Phenomenon

“…The water evaporation process during drying can be divided into three stages (Tang, Shi, et al., 2011; Zeng et al., 2020). In the first stage, the sample stays saturated with a constant evaporation rate and most of the cracks initiate during this stage.…”

Effect of Salt Content on the Evaporation and Cracking of Soil from Heritage Structures

“…With the rapid development of computer imagery, digital image processing technology has been widely used in many fields in science and engineering. In studying the process of fracture development, it is necessary to process digital images quantitatively by calculating various fracture parameters in order to analyze the geometric and morphological characteristics of the fracture network [26][27][28]. In processing digital images, the first step is to convert the original colored image (Figure 3(a)) to grayscale in order to better observe the cracks (Figure 3(b)).…”