摘要
采用改进的φ75mm杆径SHPB试验装置,对长径比为0.5的开阳磷矿砂岩进行自然风干和饱水状态下的冲击压缩试验,对比INSTRON材料试验机的静载试验结果表明:冲击载荷作用下饱水砂岩的应力–应变关系不同于其静态应力–应变关系,中应变率加载条件下饱水砂岩动态强度与风干砂岩的动态强度相近,这与静载条件下饱水砂岩强度降低的结果相反;风干砂岩动态屈服应力与其静态相近,饱水砂岩动态屈服应力比其静态下的结果提高近2倍,表现出比自然风干砂岩更强的应变率敏感性;水对砂岩动态破坏效果有影响,自然风干砂岩比饱水砂岩受冲击破坏更为严重;冲击载荷作用下,饱水砂岩动态强度应考虑其自由水黏度及Stefan效应的影响。
Impact compressive experiments on air-dried and water-saturated sandstone samples taken from Kaiyang Phosphate Mine with a constant length-diameter ratio of 0.5 are conducted with the modified φ 75 mm split Hopkinson pressure bar（SHPB） apparatus. Compared with the static mechanical results tested by INSTRON material testing machine,the SHBP test results show that stress-strain relation of water-saturated sandstone under impact loads with intermediate strain rate is different from that under static loads;and its dynamic strength is close to that of air-dried sandstone,which is opposite to the decreased strength under static load condition. For air-dried sandstone,its dynamic yield stress under impact loads with intermediate strain rate is similar to its static yield stress. However,for water-saturated sandstone,the dynamic yield stress increases by two times compared with its static yield stress,which indicates that the sensitivity of water-saturated sandstone dynamic strength dependent on strain rate is more notable than that of air-dried sandstone. Water can influence the dynamic damage patterns of sandstone,thus the impact damage of air-dried sandstone becomes more serious than that of water-saturated sandstone. So the water-free viscosity and Stefan effect of water-saturated sandstone should be considered under impact loads with intermediate strain rate.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2010年第5期1003-1009,共7页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(10872218
50934006
50674107)
关键词
岩石力学
岩石冲击动力学
SHPB试验
饱水砂岩
岩石动态强度
rock mechanics
rock impact dynamics
split Hopkinson pressure bar（SHPB） experiment
water-saturated sandstone
rock dynamic strength
