Fracture Analysis of Cohesive Soils Using Bilinear and Trilinear Cohesive Laws

Abstract

Tensile cracking of soil is an important issue that affects the strength and permeability of soil in many geotechnical applications, such as in soil dams and landfill liners. When the size of the fracture process zone is not negligible compared to specimen dimensions, a nonlinear fracture mechanics approach, such as a cohesive crack model, should be used to simulate the experimental results. A critical issue in the simulation of cohesive failure mechanism is the definition of cohesive interactions along fracture surfaces. In this study, bilinear and trilinear cohesive laws are examined based on data sets available in the literature. The inverse method is used for the definition of the cohesive parameters. As a result of this study, some conclusions are established to assess the importance of using a suitable cohesive law shape for a given soil that accurately predicts the cohesive fracture parameters under different material conditions. Finally, based on a tensile strength model of granular soil, a modified model is proposed to interpret the tensile strength of compacted clayey soils.