Improved discontinuous deformation analysis method for modeling tensile cracking in quasi-brittle materials

Tensile cracks in quasi-brittle geomaterials can degrade the stability of tunnels, pavements, and other infrastructures; however, effective modeling of the tensile fracture and subsequent collapse of such structures remains a challenging issue. The purpose of this study is to present an improved discontinuous deformation analysis (DDA) algorithm that efficiently and accurately considers the complex fracture responses of geotechnical structures composed of quasi-brittle materials. A piecewise linear cohesive contact model (PLCM) based on the fracture mechanics theory is proposed; it considers the post-peak softening behaviors of quasi-brittle materials. Then, the PLCM is integrated into the source code of the original DDA by adjusting the modeling, contact computation and open-close iteration to overcome the limitation of the original DDA in simulations of quasibrittle fracture problems. Finally, the accuracy and validity of the improved DDA for the analysis of quasibrittle fractures are demonstrated by comparing the predicted results with the experimental results and other results based on exact solutions or other existing numerical methods.