煤岩体声波波速随温度变化规律试验研究

Experiment study on acoustic wave velocity law with temperature variation in coal and rock mass

为了研究温度对煤岩体中波速传播的影响,利用自制的声波参数测试系统试验研究了煤岩体波速随温度变化规律,以期为研究声波在煤岩体中的传播提供理论参考。研究结果表明:随温度升高,煤岩体试样内纵横波波速总体表现为减小,在减小过程中会出现波动现象。试样的波阻抗大小与波速大小之间具有高度正相关特性。温度的升高将使煤岩体内各种矿物成分发生热膨胀,但由于这些矿物种类不同,其热膨胀系数也不同,导致其中的微孔隙或裂隙发生增长和扩大,煤岩体孔隙结构发生变化,煤岩体弹性模量和波速减小;另外,温度的升高会造成煤岩体内矿物质或胶结物的变化,从而导致煤岩体弹性模量和波速的降低。

In order to study the temperature affected to the wave velocity transmission in the coal and rock mass,a self developed acoustic wave parameter test system was applied to the experiment study on the wave velocity law of the coal and rock mass with the temperature variation to provide theoretical references to the study on the acoustic wave transmission in the coal and rock mass.The study reasults showed that with the temperature increased,the wave velocity of the P-wave and S-wave in the coal and rock samples would in a reduction generally and would have an undulatory phenomenon.There was a high positive correlation feature between the wave impedance size and wave velocity size of the coal samples.The temperature rose would cause heat expansion of different mineral contents in the coal and rock mass.Due to the different types of the minerals,the heat expansion coefficient would be different,the micro pores and cracks in the coal and rock mass would be increased and expanded.The porous structure of the coal and rock mass would be varied and the elastic modulus and wave velocity of the coal and rock mass would be reduced,Meanwhile,the temperature rose would cause the variation of the mineral and binding material in the coal and rock mass and thus the elastic modulus and wave velocity of the coal and rock mass would be reduced.