Behavior of the Unsaturated Granite Residual Soil and Its Effects on Embankment Project

Unsaturated soil mechanics has rapidly become a part of geotechnical engineering practice during recent decades. Hence a considerable number of studies focusing on determination of unsaturated soil property functions have been conducted on unsaturated soils. This paper presents the study of the unsaturated behavior of a granite residual soil from China by performing a series of tests. Experimental results show that the degree of saturation and shear strength are all related to the applied suctions at unsaturated states. The extended Mohr-Coulomb failure criterion can be adopted for unsaturated soil strength to consider variations in strength due to the presence of matric suction. To illustrate the effects of unsaturated behavior on geotechnical engineering practice, numerical analysis was used to investigate the seepage of the embankment taking into account the unsaturated seepage. Obtained results are valuable to correlative practical engineering when considering unsaturated problem.