Numerical study on dynamic mechanical properties of multi-jointed rock mass under impact loading using continuous-discrete coupling model

• Published in: Environmental earth sciences 2024-05, Vol.83 (10), p.309, Article 309
• Main Authors: Liu, Kangqi, Liu, Hongyan, Zhu, Fengjin, Zheng, Xiuhua
• Format: Article
• Language: English
• Subjects: Biogeosciences; Blasting; Coupling; Cracks; Destabilization; Dynamic mechanical properties; Earth and Environmental Science; Earth Sciences; Energy dissipation; Energy exchange; Environmental Science and Engineering; Geochemistry; Geology; Hydrology/Water Resources; Impact loads; Inclination angle; Jointed rock; Load distribution; Loading rate; Mathematical models; Mechanical properties; Microcracks; Numerical models; Original Article; Rock; Rock masses; Rocks; Split Hopkinson pressure bars; Stiffness; Storage modulus; Stress-strain relationships; Terrestrial Pollution; Underground mining
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-024-11632-z

The multi-jointed rock mass (MJRM) in mining, tunnel and underground engineering is prone to fracture and destabilization under the disturbance of blasting-induced dynamic wave. Study on dynamic mechanical properties of the MJRM under impact loading contributes to improving the stability of rock mass during engineering activities. A continuous-discrete coupling numerical model is developed to reproduce the laboratory Split Hopkinson Pressure Bar (SHPB) tests. The stress–strain relationship, crack types, joint penetration modes and energy dissipation characteristics of the MJRM at different joint inclination angles ( α ) are analyzed. Then the effects of the loading rate, number of joints, joint spacing ( d ) and joint stiffness on the dynamic peak strength and elastic modulus of the MJRM are discussed. It is revealed that the dynamic peak strength and elastic modulus of the MJRM are affected by the joint inclination angles, number of joints, joint spacing and joint stiffness, while the loading rate has little effect on the dynamic elastic modulus of the MJRM. The cracks generated at the joint tip do not appear to have enough time to expand under the impact loading. The main cause of the MJRM failure is the generation of the extensive micro-cracks that penetrate into each other and eventually connect with the joints to form the failure path.