Effects of fiber content and layer thickness on the final crack morphology of fine-grained coral soil by desiccation cracking tests

Purpose: Fine-grained coral soil as a special kind of marine soil, its potential application value has become increasingly prominent with the strategic goal of 'building a maritime power' proposed. It is necessary to study the modification of fine-grained coral soil to improve its crack resistance, so as to be better applied to practical engineering. Materials and methods The effects of PVA fiber (polyvinyl alcohol fiber) content and layer thickness on the final crack morphology of fine-grained coral soil were studied. Through the desiccation crack test, the final crack parameters, clod parameters, fractal dimension and crack morphology distribution of fine-grained coral soil were obtained by using image processing technology, and the quantitative analysis was carried out. Finally, the final crack morphology of fine-grained coral soil under the coupling effect of fiber content and layer thickness was obtained. Results and discussion The increase of layer thickness can reduce the number of nodes and number of crack segments, the total crack length and the fractal dimension of crack length. However, it can lead to the increase of average crack width, average crack length, total crack area, surface crack rate and surface crack ratio. The relative frequency distribution ranges of crack length and crack width are also gradually expanding. Moreover, the frequency distribution of crack length and crack width of fine-grained coral soil conforms to the Lognormal function. When the fiber content is low or no fiber is added, the frequency distribution of clod area also conforms to the Lognormal function. Conclusions Our study suggested that the crack resistance of fine-grained coral soil is improved with the increase of fiber content, which effectively inhibits the extension of cracks along the length direction and the expansion of width direction. In addition, The layer thickness also has a significant effect on the soil desiccation cracks. Revealing its law is of great significance for the potential application of fine-grained coral soil.