Desiccation cracking behaviour of a vegetated soil incorporating planting density

Abstract

Vegetation has been widely used in geotechnical engineering. However, desiccation cracking in vegetated soils is very common and often neglected. This study aims to investigate desiccation cracking behaviour of a vegetated soil considering different planting densities. The evolution of water content and surface crack pattern during drying is monitored. Experimental results show that during the early stage of drying, the evapotranspiration rate of the vegetated sample with a smaller planting density is slightly less than the evaporation rate of the bare soil sample, and the evapotranspiration rate increases with increasing planting density. In the vegetated samples, cracks initiate almost simultaneously. The larger the planting density, the more the crack initiation points and the smaller the cracking water content. In terms of the final crack pattern, both the surface crack ratio and the average crack width of vegetated samples are smaller than those of the bare sample. As the planting density increases, there are more fine and thin cracks. However, increasing planting density does not lead to a continuous decrease in cracking degree. It is necessary to select an appropriate planting density (about 24 g/m2 in this study) to maximize the inhibitory effect of vegetation on soil desiccation cracking.