钢质套筒被动围压下混凝土材料的冲击动态力学性能

Dynamic mechanical properties of concrete materials subjected to passive confining pressure produced by a steel sleeve

为了研究混凝土材料在钢质套筒侧限约束下的动态力学性能参数和破坏规律,采用分离式大直径(75mm)SHPB实验技术,测试了钢质套筒侧限约束下不同混凝土试件在不同载荷作用下轴向或径向的应力、应变峰值,平均应变率,计算了混凝土材料的损伤值,描述了加载破坏现象,对实验结果进行了分析。结果表明:混凝土材料在被动围压下,延性、抗破坏能力得到加强,具有明显的增强效应。被动围压下SHPB实验中混凝土材料的破坏应变为典型SHPB实验中破坏应变的1.8～2.8倍;破坏应力达到150MPa以上,为静力学无围压条件下的2～5倍。

The 75-mm-diameter split Hopkinson pressure bar （SHPB） technique was applied to experimentally obtain axial or radial stress and strain peaks,average strain rates of different concrete specimens laterally confined by steel sleeves under different impact loads.The damage values of concrete materials were calculated,the damage situations of concrete materials under impact load were described,and the experimental results were analyzed.It is indicated that ductibility and damage resistance of concrete materials increase under passive confining pressure.The failure strains of concrete materials under passive confining pressure is 1.8～2.8 times as large as that in the conventional SHPB experiments.Failure stress is above 150 MPa,which is 2～5 times as large as the static failure stress without passive confining pressure.The result is helpful for the investigation on security protection and failure law of concrete under the lateral confining conditions.