基于SHPB的复合岩样动态压缩破坏能量耗散分析

Energy Dissipation of Dynamic Failure of Mixed Rock Specimens Subject to SHPB Compression

应用直径50mm的分离式霍普金森压杆(SHPB)试验装置在不同应变率下对不同倾角(0°、30°、60°、90°)的复合岩样(50mm×50mm的圆柱试样)进行动态压缩试验.通过超动态应变仪监测入射杆、透射杆的应变信号,分析应变率、岩层倾角对复合岩样动态破坏过程中能量耗散的影响.研究结果表明:复合岩样的入射能、吸收能均随应变率的增大而增大;岩层倾角为0°、30°、90°时试样的能量吸收率随应变率的增大呈现出先增大后减小的趋势,倾角60°时能量吸收率则随应变率的增大呈现单调递减趋势;当应变率相近时,随着岩层倾角的增大,试样的能量吸收率呈现出先减小后增大的变化趋势,且在倾角60°时能量吸收率最小;试样在倾角60°时破碎程度远小于其他角度.

Dynamic compressive tests have been carried out for mixed rock cylindrical specimens of a dimension of 50 mm×50 mm,and of different dip angles(i.e.0°,30°,60°,90°)at different strain rates by aΦ50 mm split Hopkinson pressure bar(SHPB).Energy dissipation of the rock failure due to different strain rates and dip angles are investigated by monitoring the dynamic strain signals in the incident bar and the transmitted bar.It is found that both incident and absorption energies increase with the increasing strain rate.Regarding the rate of energy,the energy absorption rate of the rock specimens increases with the increasing strain rate and then drops as the strain rate continues to increase,for the rock specimens of dip angles of 0°,30° and 90°.While for the dip angle of 60°,the energy absorption rate decreases monotonously with the increase of the strain rate.Furthermore,under close strain rates,the energy absorption rate decreases first and then increases with the increasing dip angle,and with the minimum absorption rate occurring for the dip angle of 60°;consequently,the rock specimens of the dip angle of 60° undergo much less severe fracturing than other dip angled specimens.