Measurement of sound waves to study cumulative damage effect on surrounding rock under blasting load

Cumulative damage effect of surrounding rock in some gallery in Changba Lead-zinc Mine was studied by in-situ tests on sound waves,using RSM-SY5 intelligent sound wave apparatus,based on the sound wave measuring theory.It was shown that the damage depth of surrounding rock caused by old blasting excavation was 0.8～1.2 m,and researches on cumulative damage effect within 3.5～4.8 m were feasible according to the depth of boring holes.The acoustic wave velocity gradually decreased with the increasing of blasting times,and the damage degree(D) presented a rule of non-linear cumulation.The blasting damage degree decreased with the increasing of distance,and gradually became indistinct.The measured horizontal results were different from those of vertical,which illuminated that damage of rock mass under blasting load was anisotropic.The charge and its position could influence the damage cumulative rules of rock mass.The damage degree of rock mass within the range of charging was most severe.And the more the charge was,the more severe the damage degree of rock mass was.The test results provided references for the researches on mechanical parameters of rock mass and the stability analysis of underground chambers.