煤层顶板砂岩高温下超声传播特征分析

Experimental research on character of ultrasonic wave spreading in sandstone on upper plank of coal bed at high temperature

通过对鹤壁矿务局煤层顶板砂岩试件在高温状态下和高温冷却后的超声波测试,揭示了砂岩在高温状态下和高温冷却后的超声波传播随温度的变化规律,从声速、振幅和主频几个方面研究了在高温状态下和高温冷却后煤层顶板砂岩内损伤裂纹的发展变化过程。试验结果表明,在高温状态下和高温冷却后,振幅对岩石裂纹状态敏感程度大于声速和主频,振幅和声速随温度变化的曲线上存在着一骤降点,但各自反映的温度点有差异。其研究成果对煤炭地下气化炉围岩在高温下的节理裂隙演化过程、组构和力学特性研究具有重要的作用和意义。

This paper reveals the regulation of ultrasonic wave spreading with temperature in sandstone at high temperature and after high temperature, through testing ultrasonic wave in sandstone on upper plank of coal bed in Hebi under high temperature and after high temperature, and studies the developing and varying process of damage crack of sandstone on the upper plank of coal bed under high temperature and after high temperature from three aspects of velocity of sound, amplitude and main frequency. At the same time, the paper discusses the mechanical character of sandstone under heating. The results show that amplitude is more sensitive to crack in sandstone than velocity of wave and main frequency. There is a decreasing point on curve of amplitude and velocity of wave with temperature, but each point of temperature is deferent. The result is important to study joint fissure evolutionary process, structural fabric and mechanical character of surrounding rock at high temperature.