Study on the microstructural evolution of gangue cemented backfill under uniaxial compression

In cemented paste backfill (CPB), the connection mode and spatial position arrangement of particles determine the deformation, structural strength and stability of the backfill. Based on the scanning electron microscope images of CPB, the representative elementary area (REA) of the pore structure of CPB is obtained. The actual microstructure of CPB in PFC^2D according to REA was modeled, and the microscopic parameters of the model based on the results of indoor uniaxial compression tests were calibrated. Finally, by studying the microstructure, mechanical properties, force chain, normal contact force, tangential contact force and coordination number of CPB with different curing time (3 days, 7 days, 28 days), the internal relationship between mesoscopic parameters and macroscopic mechanical properties during CPB development was analyzed. Exploring the changes of mesostructure during the development of CPB is of great significance to the study of heterogeneous structure and multi-scale mechanical theory system.