为进一步明确多级脉冲超声波对含水煤体瓦斯解吸特征的影响，利用含瓦斯煤体超声波激励试验系统，分析了超声波持续激励不同饱水度煤体以及多级脉冲激励饱水煤体条件下，煤的孔隙结构及瓦斯解吸的变化规律，揭示出多级脉冲超声波激励含水煤体促解增流机制。结果表明：随超声波功率和煤体饱水度的增加，煤的平均孔径、比表面积和总孔容均增大；超声波功率为1 000 W时，与干燥煤体相比，煤的比表面积和总孔容增幅由煤体25%饱水度的4.369%、3.504%分别增加到100%饱水度的7.699%、8.992%；煤的瓦斯解吸量与时间呈Langmuir型关系，煤的瓦斯解吸量、解吸率均与超声波功率、煤体饱水度呈正相关性；与干燥煤体相比，煤的瓦斯解吸量增幅、解吸率增幅均随煤体饱水度增加呈线性增大趋势，超声波激励对饱水煤体的孔隙改造及瓦斯解吸影响效果最好。随超声波多级脉冲次数增加，饱水煤体的比表面积、总孔容以及瓦斯解吸量、解吸率均增大；与1 000 W超声波激励相比，煤的比表面积及总孔容增幅与多级脉冲次数呈正幂函数关系，煤的瓦斯解吸量及解吸率增幅由多级脉冲1次的2.745%、4.598%分别增加到3次的27.222%、11.106%，与多级脉冲次数呈正线性关系。多级脉冲超声波激励含水煤体产生的振动和空化复合效应，使煤基质发生疲劳损伤，强化了煤的孔隙改造效果，并加剧瓦斯分子动能，进而促进煤体瓦斯解吸，现场可通过研发多级脉冲超声波发射器结合水力化技术增透煤层抽采瓦斯。

In order to further clarify the influence of multistage pulse ultrasound on the characteristics of gas desorption in water-bearing coal, the ultrasonic stimulation test system of gas-containing coal is used to analyze the pore structure and gas desorption of coal under the condition of continuous ultrasonic stimulation of coal with different moisture contents and multistage pulse stimulation of water-saturated coal, and the mechanism of multistage pulse stimulation of water-bearing coal is revealed. The results show that the average pore diameter, specific surface area and total pore volume of coal increase with the increase of ultrasonic power and water saturation degree. When ultrasonic power is 1000 W, compared with dry coal, the increase of specific surface area and total pore volume of coal increases from 4.369% and 3.504% of 25% moisture content to 7.699% and 8.992% of 100% moisture content, respectively. There is a Langmuir-type relationship between coal gas desorption and time, and coal gas desorption amount and desorption rate are positively correlated with ultrasonic power and water saturation degree of coal. Compared with dry coal, the gas desorption capacity and desorption rate increase linearly with the increase of water saturation degree of coal, and ultrasonic stimulation has the best effect on the pore reconstruction and gas desorption of water saturated coal. With the increase of ultrasonic multistage pulse times, the specific surface area, total pore volume, gas desorption capacity and desorption rate of water-saturated coal increase. Compared with the 1000 W ultrasonic excitation, the increase of specific surface area and total pore volume of coal is a positive power function of the number of multistage pulses. The increase of gas desorption amount and desorption rate of coal increases from 2.745% and 4.598% of the first multistage pulse to 27.222% and 11.106% of the third multistage pulse, respectively, which is in a positive linear relationship with the number of multistage pulses. The combined effect of vibration and cavitation generated by multi-stage pulse ultrasonic stimulation of water-bearing coal causes fatigue damage to the coal matrix, strengthens the pore transformation of coal, and increases the molecular kinetic energy of gas, thus promoting gas desorption in coal. On site, the gas extraction in coal seam can be enhanced through the development of multi-stage pulse ultrasonic emitter combined with hydraulic technology.