砂岩与类砂岩材料的动态力学及破坏特征对比分析

Comparative Analysis of Dynamic Mechanics and Failure Characteristics ofSandstone and Quasi-sandstone Material

为了深入对比分析砂岩与类砂岩的动态力学及破坏特征,采用分离式霍普金森压杆(SHPB)和RFPA2D数值计算软件对砂岩和类砂岩进行了冲击压缩和冲击劈裂试验。在动态力学方面,对比分析了砂岩和类砂岩的应力-应变曲线演化特征与机理以及峰值应力、动态增长因子(DIF)、极限应变和损伤能的动力行为特征。在破坏特征方面,主要从宏观和细观两个层面对比分析了砂岩和类砂岩的破坏模式与损伤机理。通过结合以损伤能所定义的损伤变量,有效描述了砂岩和类砂岩的动态损伤演化特征。结果表明,尽管试验中所制备的类砂岩在一定程度上能够较好地反映砂岩的动态力学规律和损伤破坏特征,但两者之间在冲击压缩方面也存在着较为明显的差异性。SHPB数值冲击试验下砂岩和类砂岩的破坏模式和损伤演化特征与SHPB物理冲击试验结果基本一致,印证了SHPB物理冲击试验的有效性。

To deeply compare and analyze the dynamic mechanics and failure characteristics of sandstone and quasi-sandstone,the impact compression and impact splitting tests of sandstone and quasi-sandstone were carried out with the help of the split Hopkinson pressure bar(SHPB)and RFPA 2D numerical calculation software.In the aspect of dynamic mechanics,the evolution characteristics and mechanism of stress-strain curves for sandstone and quasi-sandstone,the change characteristics of peak stress,dynamic increase factor(DIF),and ultimate strain with average strain rate,and the change characteristics of damage energy with incident energy were compared and analyzed.In the aspect of failure characteristics,the failure modes and damage mechanisms of sandstone and quasi-sandstone were compared and analyzed from macroscopic and mesoscopic levels.Combined with the damage variables defined by damage energy,the dynamic damage evolution characteristics of sandstone and quasi-sandstone were effectively described.The results show that although the quasi-sandstone prepared in the test can better reflect the dynamic mechanical law and damage-failure characteristics of sandstone to some extent,there were obvious differences in impact compression between them.The failure modes and damage evolution characteristics of sandstone and quasi-sandstone under SHPB numerical impact tests were basically consistent with those of SHPB physical impact tests,which confirmed the effectiveness of SHPB physical impact tests.