吕晓聪, 许金余, 赵德辉, 葛洪海, 王泽东. 冲击荷载循环作用下砂岩动态力学性能的围压效应研究[J]. 工程力学, 2011, 28(1): 138-144.
引用本文: 吕晓聪, 许金余, 赵德辉, 葛洪海, 王泽东. 冲击荷载循环作用下砂岩动态力学性能的围压效应研究[J]. 工程力学, 2011, 28(1): 138-144.
LU Xiao-cong, XU Jin-yu, ZHAO De-hui, GE Hong-hai. RESEARCH ON CONFINING PRESSURE EFFECT OF SANDSTONE DYNAMIC MECHANICAL PERFORMANCE UNDER THE CYCLICAL IMPACT LOADINGS[J]. Engineering Mechanics, 2011, 28(1): 138-144.
Citation: LU Xiao-cong, XU Jin-yu, ZHAO De-hui, GE Hong-hai. RESEARCH ON CONFINING PRESSURE EFFECT OF SANDSTONE DYNAMIC MECHANICAL PERFORMANCE UNDER THE CYCLICAL IMPACT LOADINGS[J]. Engineering Mechanics, 2011, 28(1): 138-144.

冲击荷载循环作用下砂岩动态力学性能的围压效应研究

RESEARCH ON CONFINING PRESSURE EFFECT OF SANDSTONE DYNAMIC MECHANICAL PERFORMANCE UNDER THE CYCLICAL IMPACT LOADINGS

  • 摘要: 利用带围压装置的霍普金森压杆设备对砂岩在不同围压等级、不同应变率下的动态力学性能进行试验研究,分析了砂岩在冲击荷载循环作用下的累积比能量吸收值,损伤度与围压等参量之间的关系。研究结果表明:在围压作用下,砂岩的应力-应变曲线出现较明显的屈服平台,具有明显的脆性-延性转化特征。随着冲击荷载循环作用次数的增加,材料的弹性模量变小,试样的屈服应力降低,屈服应变有所增加。在冲击荷载作用下,砂岩的能量吸收率随着应变率的增加而提高,随围压的增加而减小。此外,岩石循环冲击损伤演化过程存在围压效应,当围压逐渐增大时,砂岩损伤度的增加随累计比能量吸收值增加的趋势变缓,其抗冲击损伤的能力增强,即围压越高,试件达到相同损伤度所需要耗散的能量越多。得到了损伤度随累积比能量吸收值和围压变化的关系式。

     

    Abstract: Dynamic mechanical performance experiments are carried out for sandstone specimens at different confining pressures and different strain rates by using the split Hopkinson pressure bar equipment with confining pressure device. The paper analyzes the relationship among the accumulative total of special energy absorbency, confining pressure, and damage of sandstone under the cyclical impact load. It is demonstrated that sandstone has BDT(brittle-ductile transformation) property, and the yield platform is observed in the stress-strain curve in triaxial state. Along with the increase of cycle numbers of impact load, the elastic modulus and the yield stress of specimen decrease, and the yield strain increases. Energy absorbency ratio increases with the augment of the strain rate, and decreases with the augment of confining pressure. When the confining pressure increases gradually, the increase rate of damage becomes slow along with the accumulative total of special energy absorbency. In summary, the higher confining pressure is, the more energy is needed for sandstone to reach the same damage level. Finally, the formulas are putted forward.

     

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