砂岩基于渗流作用下声发射的损伤分形特征研究  

Study on the damage fractal characteristics by acoustic emission based on the seepage in sandstone

作　　者：刘东 田广明 石岩 Liu Dong Tian Guangming Shi Yan(Liaoning Engineering Survey and Design Institute, Jinzhou 121000, China)

机构地区：[1]辽宁工程勘察设计院,辽宁锦州121000

出　　处：《工程勘察》2017年第4期22-26,共5页Geotechnical Investigation & Surveying

摘　　要：岩石在渗流作用下的损伤演化过程是当代岩土工程界最为关注的话题之一,为探究岩石在渗流压—应力耦合下的损伤演化特征,对取自某矿井工程的砂岩进行了三轴压缩渗流声发射试验。研究结果表明:渗透率随着应力的增加呈先减小后增大的整体趋势,在峰值应力附近达到最大值,峰后略有降低,围压越大,渗透率越小;声发射在渗透试验过程中呈阶段性变化,围压越大,声发射现象越滞后;利用weibull分布函数,基于声发射振铃计数计算得出,砂岩在渗流—应力作用下损伤量主要集中于应力加载阶段,渗透损伤仅为整体总损伤的10%~15%,且主要集中于屈服阶段之后,围压越大,渗透损伤量所占比重越小;砂岩的分形维数呈逐渐减小趋势,表明砂岩经历了一个从无序到有序的损伤演化过程,围压越大,对应的分形维数越小。The damage evolution of rock under the action of seepage is one of the most concern topics in contemporary geotechnical engineering. In order to explore the damage evolution characteristics of rock under coupling action of seepage pressure and stress, an acoustic emission test is conducted on a sandstone specimen in the three axial compression seepage condition. The results show that the permeability increases with stress increases, the maximum is near the peak stress, and then decreases slightly. The greater the confining pressure applied, the smaller the permeability is monitored ; the acoustic emission shows periodic changes in permeability test process, and the greater the confining pressure applied, the more obvious the acoustic emission phenomenon is lagged behind; the amount of sandstone damage calculated using the Weibull distribution function under the effect of seepage and stress is mainly in the stress loading stage. The seepage damage is 10% - 15% of the total damage and mainly occurs in the yield stage, and the greater the confining pressure applied, the smaller the seepage damage proportion is found; fraetal dimension decreases gradually, which shows that the damage evolution of sandstone is from disorder to order, and the greater the confining pressure, the smaller the fractal dimension is.

关 键 词：砂岩 渗流压—应力耦合 声发射 损伤 分形 

分 类 号：TU45[建筑科学—岩土工程]