Experimental study on cracking and shrinkage characteristics of granitic weathered soil during drying process

Abstract: To reveal the evolution mechanism of cracking and shrinkage characteristics of granite weathered soil under dry climate conditions, the 3D pore distribution and shrinkage curves of granite weathered soil were obtained by micron computer chromatography identification (μ-CT) scanning and shrinkage tests at different dehumidification times. Furthermore, the relationship between rules of crack evolution and characteristics of shrinkage was discussed. The test results show that the internal components of granite weathered soil can be divided into clay, quartz particles, iron cements and pores according to the 3D reconstruction model from μ-CT scanning. The total porosity and content of connected cracks increased significantly with the elapse of dehumidification time. Under the drying effects, the pores with different equivalent aperture (Re) increased to a certain extent, and the number of cracks with equivalent aperture larger than 100 μm increased most obviously. The shrinkage curve of granite weathered soil can be divided into normal shrinkage, residual shrinkage and zero shrinkage stages. Besides, the ratio of surface cracks (Rsc) can be used to predict the shrinkage characteristics of soils, but the index of three-dimensional cracks obtained by μ-CT scanning may have better correlation with the real shrinkage of soils.