Model Test Study On Stress Distribution And Attenuation Characteristics Of Rock Explosion Under Confining Pressure

Deep rock blasting project,due to the effects of self-weight stress and tectonic stress,the rock mass is in a state of high ground stress.Under the joint action of high ground stress and blast impact load,the stress distribution in the rock,rock fracture and damage are all in common with general engineering Blasting is different.In order to better study the damage characteristics of rocks during deep rock blasting in order to improve the blasting efect,a method of combining theoretical analysis and model tests was conducted to study the propagation law of explosion stress waves under different confining pressures,and a cube with a length of 375 mm was designed Concrete test blocks,pre-embedded strain bricks,and the ultra-dynamic strain test system are used to measure the radial and tangential stresses at different distances from the explosion source.The specific research work and results achieved are as follows:First,the model test of rock explosion process and stress wave propagation law under no confining pressure is carried out.Secondly,the blasting model test under unidirectional vertical pressure is carried out in the loading frame,and then the bidirectional confining pressure loading blasting model test is carried out.Through the analysis of the measured data:Under confining pressure,one-way vertical pressure and two-way confining pressure,the stress wave attenuates as an exponential function,and decreases with the increase of the proportional distance of the blast hole.During the propagation of the stress wave of the explosion under the loading of one-way vertical pressure The attenuation rate is higher,and the amplitude of attenuation will increase with the increase of the loading pressure.When the bidirectional confining pressure is loaded,the propagation efficiency of the stress wave increases first and then decreases as the pressure increases.The peak value of stress wave under unidirectional vertical pressure loading is higher than that under bidirectional confining pressure loading,and the closer to the explosion source,the greater the difference in value.The peak value of the stress wave is highest under the coupling condition at the same proportional distance measurement point,and its value gradually decreases as the uncoupling coefficient increases,and the rate of decrease is also smaller and smaller,and the attenuation curves are all exponentially decayed.Figure[39]table[12]reference[67]...