Propagation of P-SV waves radiated by explosive columns in jointed rock masses

When an explosive column initiates, it will radiate P-SV waves. The propagation of P-SV waves, which carry the majority of the explosion energy, is extremely complex in jointed rock masses. Therefore, studying the propagation of blasting stress waves in jointed rock masses is of great significance for optimizing the parameters of the blastholes and improving the economy and safety of geotechnical engineering construction. In this study, an analytical model of the propagation of P-SV waves radiated by explosive columns in jointed rock masses is derived. Using this analytical model, the maximum displacement distribution in jointed rock masses with the free surface is analyzed, and the results show: (1) when the stress waves propagate to the free surface, the reflected waves will be generated, which will produce the remarkable superposition effect with the direct waves, while the superposition effect will affect the maximum displacements at the measuring points significantly; (2) the amplitude of transmitted waves generated from the stress waves that propagate through the rock joints is smaller than that of direct waves, thus the maximum displacements at the measuring points are affected by the rock joints within a certain range; (3) the velocity of detonation (VOD) and the length of the explosive column can affect the superposition effect of stress waves, ultimately impacting the maximum displacement distribution in jointed rock masses. Therefore, optimizing the parameters of the blastholes reasonably to achieve the optimal superposition of stress waves is of great significance for improving the construction efficiency of geotechnical engineering.