Numerical and Physical Modeling of Cone Penetration in Unsaturated Soils and Numerical Simulation of Fracture Propagation in Shale Rock during Brazilian Tes

Partially water saturated condition in soils may change the cone penetration resistance comparing with that of dry or saturated conditions. This effect was investigated in this study using numerical finite element modeling and experimental centrifuge testing. The results showed suction in unsaturated soil significantly influenced the soil resistance to cone penetration. Two approaches were implemented to numerically consider the partially saturated soil condition; i.e. modifying simple constitutive models using an apparent cohesion strategy and implementing Barcelona Basic Model for unsaturated soils. Both successfully captured the cone resistance profiles inside a calibration chamber and also in free field. In addition, details of developing a miniature cone setup capable of for cone penetration inside geotechnical centrifuge was explained. Further, the use of Linear Softening Cohesive Model (LCFM) to predict the fracture growth in shale rocks during Brazilian Test was examined. The application and importance of considering two different compressive and tensile elastic modulus and soil anisotropy during the fracture modeling of shales were demonstrated.