饱水砂岩SHPB试验研究与耗能分析

Experimental Study and Energy Consumption Analysis of SHPB in Water-Saturated Sandstone

深部工程岩石常处于饱水状态,爆破开采时往往承受各种复杂的冲击力作用。为保障施工安全高效进行,研究不同冲击荷载下饱水砂岩的动态力学性能有着理论指导意义。试验测量饱水处理后砂岩试件的基本物理参数,并采用分离式霍普金森压杆装置(SHPB)对饱水砂岩试件开展6种不同冲击荷载作用下的动态压缩试验。结果表明:饱水砂岩试件动抗压强度随加载速率增大而增大,呈二次多项式关系,正相关性显著;随应变率提高,动抗压强度增长,两者近似指数函数关系;动应变受应变率作用明显,表现为二次增长关系;试件压缩破坏时的破碎程度随冲击速率增大而增大。随冲击气压增加,试件破裂面逐渐增多,吸收能量也越多,破碎程度加剧,碎块尺寸减小。

Deep engineering rocks are often in a saturated state,and often bear various complex impact forces during blasting and mining.In order to ensure the safe and efficient construction,it is of theoretical significance to study the dynamic mechanical properties of saturated sandstone under different impact loads.The basic physical parameters of the sandstone specimens after water saturation treatment were measured,and the dynamic compression tests of the saturated sandstone specimens under six different impact loads were carried out by using the split Hopkinson Compression Bar Device(SHPB).The results show that the dynamic compressive strength of the saturated sandstone specimen increases with the increasing of the loading rate,showing a quadratic polynomial relationship and a significant positive correlation,the dynamic compressive strength increases with the increasing of the strain rate,which is approximately exponential,the dynamic strain is obviously affected by the strain rate,which is a secondary growth relationship,and the degree of fragmentation increases with the increasing of the impact rate.With the increase of impact pressure,the rupture surface of the specimen gradually increases,the more energy absorbed,the degree of crushing intensifies,and the size of the fragments decreases.