单轴受压高温损伤砂岩的电学响应特征

doi:10.12068/j.issn.1005-3026.2023.04.014

摘要/Abstract

摘要： 为研究高温损伤后砂岩的电学响应特征，对常温和经过200，400，500，600，800℃加热水冷却后的绿砂岩岩样开展了单轴压缩试验，并实时监测了岩样在压缩过程中的电阻率变化规律.结果表明:对应于岩石在单轴压缩过程中的压密阶段、裂纹稳定扩展阶段、裂纹快速扩展阶段和破坏阶段，高温水冷却岩石电阻率的变化表现为电阻率小幅增加、电阻率平稳增加、电阻率增幅加大、电阻率急剧下降四个阶段.当加热温度低于400℃时，在初始压密段，电阻率变化率低于10%，当加热温度高于400℃后，在初始压密段电阻率变化率变化幅度增大，加热温度为800℃时，在初始压密段的电阻率变化幅度达50%左右，表明初始压密段电阻率的变化率可以反映岩石的初始损伤程度；当压力达到岩石峰值强度的80%~90%时，电阻率变化率达到峰值，随后出现骤降，说明电阻率变化率曲线的突降可以作为岩石发生破坏的电学前兆；电阻率变化的各向异性特征能够在一定程度上反映受压岩石最终贯通裂纹出现的位置，在潜在贯通裂纹附近的电阻率变化最为显著.

关键词: 单轴压缩；电阻率；高温；损伤；前兆

Abstract: In order to study the electrical response characteristics of sandstones after high temperature， uniaxial compression tests were carried out on green sandstone samples at room temperature and heated at 200， 400， 500， 600 and 800℃， and the change law of resistivity during compression was monitored in real time. The results showed that corresponding to the compaction stage， stable crack growth stage， rapid crack growth stage and failure stage of rocks under uniaxial compression， the resistivity change of water-cooled high temperature sandstones shows four stages:small increase， steady increase， significant increase and sharp decrease of resistivity. When the heating temperature is lower than 400℃， the resistivity changing rate in the initial compaction state is under 10%， while when the heating temperature is over 400℃， the changing rate of resistivity increases and can be up to 50% when the heating temperature is 800℃. This indicates that the changing rate of resistivity can reflect the incipient damage degree in rocks. When the compressive pressure reaches 80%~90% of the peak strength， the changing rate of resistivity reaches its peak value， and then decreases sharply， which can be used as a precursor of rock failure. The anisotropic characteristics of resistivity change can indicate the location of the penetrated crack in such a way that the most significant change of resistivity can be observed near the upcoming penetrated crack.

Key words: uniaxial compression; electrical resistivity; high temperature; damage; precursor

中图分类号:

TU45

贾蓬，李博，祝鹏程，王琦伟. 单轴受压高温损伤砂岩的电学响应特征[J]. 东北大学学报（自然科学版）, 2023, 44(4): 558-564.

JIA Peng， LI Bo， ZHU Peng-cheng， WANG Qi-wei. Electrical Response Characteristics of High Temperature Damaged Sandstones Under Uniaxial Compression[J]. Journal of Northeastern University(Natural Science), 2023, 44(4): 558-564.

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