Energy evolution and damage characteristics of sandstone with different bedding spacing based on NSCB impact test
In this study,the split Hopkinson pressure bar test system(SHPB)is used to carry out dy-namic impact tests on straight-cut semicircular sandstone specimens(NSCB)with bedding spacings of 6 mm,8 mm and 10 mm,and a high-speed camera is used to record the failure pattern and analyze the sandstone.The stress and strain response characteristics,energy evolution characteristics and the energy evolution duration of each stage are analyzed under different bedding spacing conditions,and the damage characteristics are analyzed.The discrete lattice spring model(DLSM)was used to simulate the dynamic fracture process of sandstone specimens under different bedding spacing conditions,and the stress,strain,energy evolution and damage characteristics of the rock matrix between the beddings are ana-lyzed,and the total kinetic energy is explored according to the kinetic energy evolution curve and loss of kinetic energy dissipation.The results show that the dynamic fracture morphology and stress and strain characteristics of sandstone are significantly affected by the change of the bedding spacing.The secondary cracks decrease with the increase of bedding spacing;the stress and strain peaks increase with the crack propagation speeding up.The duration of each stage of energy evolution decreases with the in-crease of crack propagation speed;the peak value of releasable elastic strain energy decreases with the increase of bedding spacing,and the peak value of total absorbed energy and dissipation energy increases continuously.When the interlayer spacing increases,the growth rate of the damage curve is higher in the initial stage,while the attenuation decreases in the later stages.The peak values of stress,strain and en-ergy evolution curves of the rock matrix between beddings decrease with the increase of the bedding spacing,and their correlations weaken as the rock matrix moves away from the centerline of the kerf.
万方数据
维普
