三轴SHPB加载下砂岩力学特性和破坏模式的试验研究

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振动与冲击 ›› 2012, Vol. 31 ›› Issue (8) : 29-32.

论文

三轴SHPB加载下砂岩力学特性和破坏模式的试验研究

宫凤强1,2，李夕兵1,2，刘希灵1,2

作者信息 +

Experimental study of sandstone mechnical properties and failure model under triaxial SHPB loading

GONG Feng-qiang1,2, LI Xi-bing1,2, LIU Xi-ling1,2

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摘要

利用改造的三轴SHPB动静组合加载实验装置，对均质砂岩进行了不同围压和不同应变率下的三轴冲击压缩试验，作为对比利用RMT-150C试验机也进行了部分准静态下的三轴压缩实验。根据实验结果，分析了围压对砂岩动态冲击性能的影响，并重点讨论了冲击过程中岩石的破坏模式。研究结果表明，在围压一定的情况下，岩石的动态压缩强度随应变率的提高而提高；在应变率相同的情况下，岩石的动态压缩强度和弹性模量会随着围压的增大而增大。岩石发生破坏的临界入射能，随着围压的增大而增大。岩石单位体积吸收能与应变率之间呈线性递增关系，而且递增的程度随着围压的增加而增加。三轴冲击加载下，应变率较低时岩石内部形成压剪破裂面但整体不失稳，应变率很大时岩石破碎形成锥形块体形式。

Abstract

The dynamic triaxial compression tests of sandstone were conducted with a modified triaxial split Hopkinson pressure bar (SHPB) coupled static and dynamic loads. For the comparison, the quasi-static triaxial compression tests were also conducted with RMT-150C device. The influence of confining pressure to dynamic characteristics of sandstone and the failure model of sandstone in impact tests were focused on in this paper were analyzed based the experimental data.The results show that the dynamic compression strength will increase with the increase of strain rate when the confining pressure is a constant. When the strain rate is a constant, the dynamic compression strength and elastic modulus will increase with the increase of confining pressure. The critical incident energy for rock failure will increase when the confining pressure increases. There is a linear increasing relationship between the energy absorption per unit volume of rock and strain rate. Under the triaxial dynamic impact, there are some compression-shear surfaces inside the rock and the rock will remain steady when the strain rate is low, when the strain rate is high, rock will failure and generate some vertebral-shaped blocks.

导出引用

宫凤强;李夕兵;刘希灵;. 三轴SHPB加载下砂岩力学特性和破坏模式的试验研究[J]. 振动与冲击, 2012, 31(8): 29-32

GONG Feng-qiang;LI Xi-bing;LIU Xi-ling;. Experimental study of sandstone mechnical properties and failure model under triaxial SHPB loading[J]. Journal of Vibration and Shock, 2012, 31(8): 29-32