热损伤砂岩力学与超声时频特性研究

发布时间：2018-06-15 20:30

本文选题：岩石力学 + 砂岩　；参考：《岩石力学与工程学报》2014年09期

【摘要】：岩石经历高温作用后会产生不同程度的热损伤。通过单轴压缩试验,对经历25℃,100℃,200℃,400℃,600℃,800℃,1 000℃高温作用后的砂岩试样力学特性进行分析;通过超声纵波试验,基于小波变换方法,在时域和频域对其超声特性进行研究。提出频谱峰度(KFS)的概念,用以描述超声信号频率分布的杂乱/集中程度。研究发现:随着作用温度的升高,砂岩试样表面色调变暖,纵波波速显著降低,波形趋于紊乱,峰值应变增大,峰值应力、弹性模量变化呈现出非线性特征。在频域对超声信号进行分析发现,砂岩试样接收谱形心频率和频谱峰度随温度的变化呈非单调性,其与峰值应力、弹性模量的变化规律有较强的一致性。砂岩是一种典型的矿物胶结岩,矿物颗粒和胶结物在高温作用下产生不同变化,并对砂岩的各项特性产生不同影响。以宏观的声学力学特征变化探究不同等级高温作用后砂岩的热损伤,研究结果对高温环境岩石工程具有一定的指导意义。
[Abstract]:Through the uniaxial compression test, the mechanical properties of the sandstone specimens after 25, 100, 200, 400, 600, 800, 1000 C are analyzed by uniaxial compression test, and the ultrasonic characteristics are studied in time and frequency domain by the ultrasonic longitudinal wave test. The concept of spectral kurtosis (KFS) is proposed to describe the disorder / concentration degree of the frequency distribution of ultrasonic signals. It is found that as the temperature increases, the surface tone of the sandstone specimen is warmer, the wave velocity of the longitudinal wave decreases significantly, the waveform tends to be disorganized, the peak strain increases, the peak stress and the modulus of elasticity show nonlinear characteristics. The analysis of acoustic signal shows that the frequency and kurtosis of the spectrum centroid of sandstone specimen are non monotonicity with the change of temperature, which is consistent with the variation of peak stress and modulus of elasticity. Sandstone is a typical mineral cementation rock, mineral particles and cements have different changes under the action of high temperature, and the sandstone is different. The characteristics of the term have different effects. The thermal damage of sandstone after different grades of high temperature is explored by the change of macroscopic acoustic mechanics characteristics. The results are of certain guiding significance to the rock engineering of high temperature environment.
【作者单位】：空军工程大学机场建筑工程系;西北工业大学力学与土木建筑学院;
【基金】：国家自然科学基金资助项目(51378497)
【分类号】：TU452

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