抄録
Hydro collapsible soils are of kinds of problematic soils which show high shear strength at low degrees of saturation but due to wetting, their Meta stable structure collapses and will be subjected to large deformation. In this study by applying isotropic triaxial loadings to undisturbed samples, mechanical behavior of a highly collapsible loessial soil has been assessed. During tests, matric suction of the samples was controlled as well as the mean net stress, and the variation of the degree of saturation was monitored continuously. Two types of stress paths were conducted on the samples namely “Isotropic induced collapse” under applying constant matric suctions and “wetting induced collapse” by decreasing matric suction while applying constant mean net stress. Results show increasing yielding stress of the samples by increasing the mean stress under constant matric suctions. By considering effective stress approach, a hardening model is introduced in this paper to interpret the behavior of the tested soil. Agreement obtained between the predicted and measured values of the yielding stresses during tests is promising and shows the efficiency of the presented model.
