摘要
为研究脆性红砂岩在干湿循环条件下,孔隙率变化情况、变形破坏特征以及声发射特征,进行了10次干湿循环试验。结果表明,最初的孔隙变化主要是小开孔隙过渡为大开孔隙,随循环进程小开孔隙呈小幅度波动,但大开孔隙呈对数增长;干燥、饱和的单轴抗压强度均呈对数降低趋势;而结合声发射特征曲线可以更合理地把脆性红砂岩单轴压缩过程划分为3个显著阶段:裂隙压密阶段、弹性变形阶段、宏观破坏阶段。随干湿循环次数的增多,因孔隙的逐渐扩大、增多,压密阶段的声发射事件有逐渐增多的趋势;累计计数的突变可以作为弹性变形阶段后岩石内部关键断裂初始扩展、贯通的依据;宏观破坏阶段声发射累计计数占比随循环次数有降低趋势,脆性红砂岩低次干湿循环的变形破坏高度集中在宏观破坏阶段,随着循环次数的增加,孔隙的增大、增多,变形破坏有提前发生的趋势,大量声发射活动逐渐提前,且破坏形式有脆性破坏向延性破坏的过渡趋势。
In order to study the porosity change,deformation and acoustic emission characteristics of brittle red sandstone under the condition of dry-wet cycle,10 dry-wet cycle tests were carried out. The results show that the initial porosity change was mainly the transition from the small pores to the larger ones,and the small pores fluctuated slightly with the circulation process,while the large pores increased logarithmically. The dry and saturated uniaxial compressive strength decreased logarithmically. The uniaxial compression process of brittle red sandstone could be divided into three significant stages through the acoustic emission characteristic curve: fracture compaction stage,elastic deformation stage and macro failure stage. With the increase of the dry and wet cycles,the acoustic emission events in the compaction stage tended to increase due to the gradual expansion and increase of the pores. The sudden change of the cumulative count could be used basically for the initial expansion and breakthrough of the key fractures in the rock after the elastic deformation stage;the cumulative count proportion of acoustic emission in the macro failure stage tended to decrease with the number of cycles,and the brittle red sandstone had a low dry and wet cycle. With the increase of the cycles and the porosity,the deformation failure tended to occur in advance,as well as a large number of acoustic emission activities,and the failure mode trended to transit from brittle failure to ductile failure.
作者
李达朗
杨根兰
鲁鲲鹏
龙登武
LI Dalang;YANG Genlan;LU Kunpeng;LONG Dengwu(College of Resources and Environmental Engineering,Guizhou University,Guiyang 550025,China)
出处
《贵州大学学报（自然科学版）》
2020年第2期79-85,共7页
Journal of Guizhou University:Natural Sciences
基金
贵州省科学技术项目资助(黔科合J字2244)
贵州省科技平台及人才团队计划项目资助(黔科合平台人才[2017]5402号)
关键词
干湿循环
红砂岩
孔隙率
声发射
dry-wet cycle
red sandstone
porosity
acoustic emission
