水分对煤岩体声波波速影响实验研究

水分对煤岩体声波传播波速有重要的影响,而煤样微观孔裂隙结构及所含胶结物又直接影响煤岩体的含水率。为此,利用SEM扫描电镜对煤样进行扫描,分析其微观孔裂隙结构及所含胶结物和吸水能力,然后通过对煤样在常温常压下吸水,测定不同吸水率条件下的声波波速,探寻煤岩体波速随水分不同的变化规律。研究结果表明:官地煤样有少量的微孔隙,并有微量的胶结物碎屑存在;马兰8#煤样表面特征无明显的孔隙、裂隙结构特征,却可以看到较多胶结物碎屑。马兰8#煤样的吸水率为2.49%,而官地煤样的吸水率仅为1.31%。随着吸水率的增大,煤样内纵横波波速有增大趋势。波速变化的机理主要受煤样含水量和煤样弹性模量变化两种作用的相互影响。

Influence of Water on Acoustic Wave Velocity in Coal and Rock Body

Water content has an important influence on acoustic wave velocity of coal and rock body, and pore structure directly affects water content of coal and rock body. Thus, the pore structure and absorbing capacity of coal and rock body were analyzed by scanning electron microscopy (SEM). Then the acoustic wave velocities of coal samples under different water absorption conditions were measured by absorbing water at normal temperature and pressure, and the variation law of wave velocities of coal and rock body with different water content was explored. The research results show that the pore development of coal and rock body in Guandi Mine is better than that in Malan Mine. The water absorption of coal and rock body in Malan Mine is 2.49%, while that of coal samples in Guandi Mine is only 1.31%. With the increase of water absorption, the velocity of longitudinal and shear waves in coal and rock body tends to increase. The mechanism of wave velocity variation is mainly influenced by the water content and the elastic modulus of coal and rock body.