Numerical study on the mechanical and failure characteristics of rock-concrete combination under uniaxial compression

DONG Zhuo; WANG Yongxia; YUAN Ruifu

doi:10.16186/j.cnki.1673-9787.2023070015

Abstract：Objectives This study aims to investigate the effects of aggregate content,strength grade,propor-tion,and interface angle of concrete components on the mechanical properties and failure characteristics of rock-concrete composites under uniaxial compression conditions.Methods A numerical model of the com-posite body was constructed using a convex polygon random aggregate generation deployment program and the RFPA2D analysis system.Numerical simulations were conducted to analyze four types of composite specimens.Results The results show that the failure types of the composite can be classified into two catego-ries:two-body type Ⅰ and Ⅱ failures,caused by the failure of the concrete component extending to the granite component or the simultaneous failure of both components and the interface,and single-body typeⅠ and Ⅱ failures,caused by the failure of the concrete component alone or the simultaneous failure of the concrete component and the interface.The stress state analysis at the interface provided a theoretical expla-nation for the formation of macro-cracks along the interface.The compressive strength of the composite was close to the uniaxial compressive strength of concrete.Its value was positively correlated with the strength grade of the concrete component and negatively correlated with the proportion.The numerical simulation re-sults of the elastic modulus of the composite were in good agreement with the theoretical values.They showed a positive correlation with the aggregate content and strength grade and a negative correlation with the proportion and interface inclination angle.The Poisson's ratio of the composite was negatively corre-lated with the aggregate content and proportion,while the influence of the strength grade on it was rela-tively small.Additionally,both the compressive strength and Poisson's ratio of the composite exhibited a decreasing-then-increasing trend with increasing interface inclination angle.Conclusions A numerical model of concrete-rock composite specimens containing aggregates was constructed,and numerical simula-tions were conducted on four types of composite specimens using the RFPA2D analysis system.The me-chanical properties of the composite specimens can be enhanced by increasing the strength of concrete com-ponents,reducing the proportion of concrete,and decreasing the interface angle between materials.The re-sults provide a basis for the stability analysis of underground or dam engineering.