Cracking behavior of soil subjected to the recycling of fly ash in semiarid regions

The occurrence of soil cracks can damage the soil structure and lead to soil instability, which can induce landslides and other geological disasters. To investigate the inhibitory effect of fly ash on soil cracking, digital image processing and scanning electron microscopy were employed to quantify the soil cracking process. Parameters such as the fractal dimension, porosity, and crack ratio were used to evaluate the influence of fly ash on soil cracking. The results revealed that with decreasing water content, the fracture rate and fractal dimension of a sample tended to increase and finally stabilized. The addition of fly ash increased the crack time and residual moisture content of the samples. The samples with 4%, 8% and 16% fly ash had 37.34%, 76.08% and 102.3% greater water contents, 6.68%, 12.74% and 22% smaller fractal dimensions, and 9.6%, 17.8% and 28.27% smaller fracture rates, respectively, than did those without fly ash. This study provides a theoretical basis for the application of fly ash in slope protection and other geological disasters.