Study of the Damage Evolution Process and Micromechanics Constitutive Model of Microcrystalline Limestone under Periodic Blasting Load

Abstract

The cumulative damage to rock and soil mass caused by blasting in tunnel, highway, hydropower, and other projects is very complex, but the process of damage evolution is still unclear. This study took Zhujiapo mining area limestone as the research object and analyzed the change in its strength and mechanical parameters with periodic blasting loads. Combined with damage mechanics theory and microcrack propagation zone theory, a micromechanics constitutive model considering cumulative damage evolution was developed. The results show that (1) periodic blasting loads have a continuous cumulative effect on microcrystalline limestone, the peak strength and elastic modulus of which decrease exponentially with increasing blasting cycles; (2) periodic blasting loads cause crystal fractures, microcrack initiation, and propagation; and (3) the micromechanics damage constitutive model considering confining pressure and periodic blasting loads well describes the micromechanics behavior of microcrystalline limestone in the Zhujiapo mining area. The research results provide a theoretical reference to the study of rock damage mechanical properties under periodic blasting loads.