Study on the failure behavior of three di erent stabilized problematic soils

In this study laboratory testing of e ectiveness of cement treatment has been made on geotechnical parameters of problematic soils encountered in southern coast line of Caspian Sea, Iran. Gorgan loess, Rasht clay, and Anzali sand were selected in this research. Addition of cement was found to improve workability and increased uncon ned compressive strength, and elastic modulus of soils signi cantly. Triaxial test results indicated that cement treatment not only improved shear strength remarkably, but also it changed the type of failure greatly from ductile to brittle behavior. The large scale direct shear test results showed signi cant improvement in shear strength and shear modulus. Besides, the brittle behavior of cement treated samples was observed. Eventually, it was found that the trend of failure envelope of cement treated samples was non-linear, and some failure criteria such as modi ed Grith theory, Hoek-Brown theory, and the Johnston criterion can describe the soil cement behavior satisfactorily.