砂岩动静态拉伸力学性能试验与对比分析

通过对皖北矿区3个煤矿砂岩岩样加工成厚径比为0.5的圆盘试件,利用变截面分离式Hopkinson压杆(SHPB)试验装置,采用不同加载冲击气压驱动撞击杆高速运动,对圆盘试件实施不同加载速率下的动态劈裂拉伸试验,得到了3种砂岩试件的动态拉伸应力和应变率等力学参数,并与静态劈裂拉伸试验结果进行对比,分析了砂岩圆盘试件动静态劈裂破坏形态、动态拉伸应力与加载速率相关性规律;得到了试验冲击气压范围内砂岩动态拉伸应力强度与平均应变率之间近似为乘幂函数关系,比其静态拉伸应力强度提高2～3倍。对砂岩动静态拉伸力学性能研究做了一些有益的探索。

Comparative Analyses on Dynamic and Static Tensile Performances of Sandstone

Variable cross-section split Hopkinson pressure bar (SHPB) apparatus was adopted in the dynamic splitting test of three kinds of sandstone from different mines in Wanbei mine area,Anhui Province. The specimens were processed into disc with thick-diameter ratio 0.5 and various impact pressures were used to drive striker bar to get various loading rates. The dynamic results of 3 kinds of sandstone, such as dynamic tensile stress and strain rate, were compared with static splitting test results to analyze dynamic and static failure modes of specimens. Moreover, correlation rules of tensile stress and loading rates was also investigated. There is a power relationship between dynamic tensile strength and average strain rate in the range of tested impact pressure and the dynamic tensile strength is about 2 to 3 times more than static tensile strength. This paper would provide some beneficial exploration in the dynamic and static tensile properties research of sandstone.