Influence of joint roughness on the shear performance of grouted rock mass: Numerical investigation with an improved traction-separation model

Abstract

In this study, the coupled FEM-DEM method (FDEM) is adopted to investigate the mechanical response of grouted joint. To realistically capture the post-peak mechanical performance of grouted joint, an improved T-S model is developed by transforming the classical bilinear T-S model into an elastic-brittle T-S model. The validation results show that the improved T-S model can accurately describe the mechanical response of grouted joints under various normal loading conditions. Then, several compressive-shear simulations on grouted joint with different Joint Roughness coefficients (JRCs) and normal loads (Fs) were conducted based on the proposed model. Finally, comprehensive analysis was made to study the effects of JRC and F on the deformation characteristics and mechanical behavior of grouted joint. The results indicate that as JRC ranges from 6.57 to 19.1, the cohesion and internal friction angle exponentially increase by 30.8% and 13.4%, respectively. Moreover, JRC has a significant influence on shear displacement corresponding to peak strength, cohesion, and internal friction angle, while F strongly affects with shear displacement corresponding to peak strength and peak shear strength.