Investigation of the tensile and mixed mode (tensile and shear) fracture properties of cement-stabilized soils by numerical analysis

Abstract

In this study, crack initiation, crack propagation, and fracture failure of soil specimens stabilized with cement, an elasto-plastic material, are investigated by numerical analyses. There is no international standard recommended in the literature to find the mode I and mixed mode I-II (tensile and shear) failure values of reinforced soil materials. The aim of this study is to investigate the applicability of ASTM C78, an international standard recommended for concrete specimens, for both indirect tensile and tensile-compression strength tests. Stress and crack analyses in beam specimens were performed using FRANC2D software. The indirect tensile fracture toughness (KIC) value of the modelled beam specimens was found to be 0.32 MPa√m. Similarly, the indirect tensile and shear fracture toughness values were found to be 0.38 MPa√m. Both non-cohesive and cohesive crack analyses were performed in numerical modeling. Numerical analysis results showed that the most significant slipping between the cohesive crack surfaces was observed in the specimen under mixed mode I-II loading. Moreover, "wing crack" growth in cement-stabilized soil specimens was obtained in numerical modeling in accordance with the principles of fracture mechanics. It is believed that the results of this study will lead to a new international standard for the determination of mode I and mixed mode I-II fracture toughness of cement-stabilized soil specimens.