摘要
为研究不同饱和度砂岩在不同应力路径下电阻率及声发射信号演化规律,尤其是声发射平静期内电阻率的响应特征,采用干燥、半饱和及饱和红砂岩试件分别开展单轴压缩、等幅循环加卸载和增幅循环加卸载试验。试验结果表明:电阻率变化均与应力具有较好的一致性,能够反映岩石在荷载作用下内部孔隙变化和微裂隙压密闭合、裂纹萌生及扩展;随饱和度的增加,声发射平静期明显增加,电阻率的变化能够有效反映声发射平静期内亚临界裂纹的扩展和岩石内部损伤的累积;不同加载路径下,干燥试件导电机制为骨架导电,电阻率总体呈上升趋势;饱和试件导电机制主要为水导电,电阻率整体表现为下降趋势;当增幅循环加卸载应力超过峰值强度50%后,不同饱和度红砂岩Kaiser效应消失,Felicity效应出现,Felicity比随应力水平提升逐渐减小。
To investigate the evolutionary patterns of resistivity and acoustic emission in sandstone with varying saturation levels under different loading paths,particularly focusing on the resistivity characteristics during the quiescent phase of acoustic emission,we conducted uniaxial,constant amplitude cyclic loading,and increased amplitude cyclic loading tests on dry,semi-saturated,and saturated red sandstone specimens,respectively.The test results reveal a close correlation between resistivity changes and stress levels,offering insights into internal pore alterations and the compaction,initiation,and development of micro-cracks within the rock under loading conditions.As saturation increases,the quiescent period of acoustic emission before failure exhibits a significant extension.The variation in resistivity effectively mirrors the propagation of sub-critical cracks and the accumulation of internal damage within the rock during the quiescent phase of acoustic emission.Under distinct loading paths,the conduction mechanism in dry specimens is primarily skeleton conduction,demonstrating an overall upward trend.In contrast,saturated specimens predominantly exhibit water conductivity,leading to a downward trend in resistivity.During cyclic loading,when stress levels exceed 50%of the peak strength,the Kaiser effect in red sandstone with different saturations diminishes,giving way to the Felicity effect,accompanied by a declining Felicity ratio.
作者
贾蓬
王茵
王琦伟
卢佳亮
JIA Peng;WANG Yin;WANG Qiwei;LU Jialiang(School of Resources and Civil Engineering,Northeastern University,Shenyang,Liaoning 110819,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2024年第S01期3333-3341,共9页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(52174071)
