A Cohesive Model-Based Nonlinear Discontinuous Deformation Analysis for Tensile Fracture in Geotechnical Materials.

Tensile cracks significantly influence stability of mining, tunneling, and other geotechnical engineering scenarios. Discontinuous deformation analysis (DDA) is widely employed to analyze, predict, and prevent the deformation and progressive failure of such geomaterials. However, an accurate and efficient simulation of the cracking process remains a challenge, requiring appropriate fracture models. This study presents an improved DDA algorithm featuring a nonlinear cohesive zone model (CZM) designed for the intricate deformation and fragmentation analysis of geotechnical structures composed of quasi-brittle materials. Building upon fracture mechanics theory, an exponential-type CZM that accounts for both post-peak softening behaviors and nonlinear relations inherent in quasi-brittle materials is introduced. This exponential-type CZM is integrated into the original DDA method, addressing the co-edge blocks connected with cohesive springs. The ensuing unbalanced force in normal contact arising from the nonlinear cohesive spring is mitigated using a nonlinear iterative algorithm. The formulation, the implementation, and the iteration of the exponential-type CZM within the DDA framework are elucidated. Finally, the feasibility and the accuracy of the improved DDA for analyzing quasi-brittle crack propagation are demonstrated and validated by comparing several examples with experimental and numerical results. Highlights: An improved DDA, incorporating an exponential-type CZM, is presented to simulate the nonlinear fracture behaviors in geomaterials. A nonlinear iterative algorithm is proposed to address the solution of nonlinear equilibrium equations in the improved DDA. The effectiveness and the accuracy of the improved DDA are validated and verified through typical examples. [ABSTRACT FROM AUTHOR]