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高温作用后石灰岩受压破裂过程的声发射试验研究
Acoustic Emission Characteristics of Limestone during Compression and Fracture after High Temperature
【摘要】 利用声发射测试和单轴压缩试验相结合的方法,研究了河南焦作矿区的石灰岩在100~800°C高温压缩破坏条件下的声发射过程,结合不同温度下石灰岩的力学性质,分析不同声发射参数条件下石灰岩在不同受力阶段的声发射特点.结果表明:在高温作用下石灰岩出现了明显的声发射现象;石灰岩峰值应力随着作用温度的升高而不断降低,800°C以后,峰值应力较600°C时降幅达50%,但是峰值应变随着作用温度的升高而变化不明显;在400°C以前,声发射振铃累计数均值随着温度的升高而增加,400°C后随着温度的升高而不断降低;在600~800°C时,试样呈现出明显的塑性破坏特征,高温致使石灰岩劣化,声发射试验中,振铃累计数大幅度降低,应力与应变和声发射特征参数变化规律较吻合.
【Abstract】 The mechanical properties and acoustic emission evolution process of limestone under the action of high temperature load were investigated by combining the methods of acoustic emission technique and uniaxial compression test.The temperature varies in the range of 100,200,400,600 and 800 °C.Acoustic emission characteristic parameters and the mechanical parameter under different temperatures were analyzed.The results show that the temperature affects the acoustic emission phenomenon of limestone obviously,the peak stress decreases as the temperature increases and drops by 50 percent from 600 °C to 800 °C,but the peak strain changes not obviously;the average accumulative ring-down count increases as the temperature increases before 400 °C but reduces unceasingly as the temperature increases after 400 °C;the specimens present obvious plastic failure characteristic after 600 °C,the accumulative ring-down counts decrease obviously and conform to the stress-strain curve.
【Key words】 high temperature; limestone; compression fracturing; acoustic emission; accumulative ring-down count;
- 【文献出处】 上海交通大学学报 ,Journal of Shanghai Jiaotong University , 编辑部邮箱 ,2011年05期
- 【分类号】TU452
- 【被引频次】7
- 【下载频次】203