应力速率对岩石声发射特征影响的试验研究

Test Research for the Influence of Stress Rate on Granite Acoustic Emission Characteristics

在刚性试验机上对花岗岩岩样进行单轴加载试验,在应力速率分别为20,30,40kN/min条件下对花岗岩受力变形过程中的力学特性和声发射特性进行了测试和分析。随应力速率的增大,花岗岩的抗压强度依次提高,应力速率越大,岩石的破坏越趋于剧烈;声发射活动伴随花岗岩单轴压缩破坏全过程,在压密阶段及弹性变形阶段,声发射活动不显著,声发射信号较少,而在应力水平达到岩样抗压强度的95%左右时,声发射参数出现剧增;应力速率为30kN/min时,声发射活动最剧烈,且破坏时的累积声发射数也最多。试验结果表明,应力速率对花岗岩的力学特性和声发射信号特性具有显著的影响。

Uniaxial loading tests of granite were conducted by rigid testing machine.Under the stress rate of 20,30,40kN/min, mechanics characteristic and acoustic emission characteristic of granite during loading and deformation were tested and analyzed.The compressive strength of granite gradually enhanced with the increase of stress rate.And the higher loading rate,the severer damage of granite samples.Acoustic emission activities accompanied the uniaxial failure process of granite.In consolidation process and elastic deformation stage,acoustic emission activities were not obvious and signals were less.While the stress reached the rock compressive strength of 95%,the acoustic emission parameters would leap.When the stress rate was 30kN/min,acoustic emission activities were the severest,and the cumulative acoustic emissions in failure were the most.The results showed that the stress rate had significant influence on mechanics characteristic and acoustic emission characteristic of granite.