1. School of Energy Engineering,Xi’an University of Science and Technology;Xi’an　 710054,China;2. School of Environmental Protection and Safety Engi-neering,University of South China,Hengyang　 421001,China

为研究低频机械振动作用对含瓦斯煤孔隙率的影响,建立煤体孔隙瓦斯压力、吸附膨胀力、振动衰减挤压应力作用下振动动态孔隙率方程。采用前人得出的煤体孔隙率与单轴抗压强度变化规律,以及不同频率、不同时间振动型煤试件后的煤体单轴抗压强度变化试验对方程进行检验,结果显示:低频振动作用下,振动频率相同,振动时间越长,煤体单轴抗压强度越小,孔隙率越大;振动时间相同,振动频率越小,煤体单轴抗压强度越大,孔隙率越小,且30 Hz与20 Hz单轴抗压强度、孔隙率差值要小于20 Hz与10 Hz之差。表明振动使煤体孔隙率增大,从而减小了煤体单轴抗压强度,且振动频率从10,20,30 Hz逐渐增加,孔隙率逐渐变大,单轴抗压强度相应变小,计算孔隙率能正确反映振动后煤体单轴抗压强度变化规律。对比计算孔隙率和试验单轴抗压强度关系进一步得到前人得出的单轴抗压强度随孔隙率变化曲线呈现类指数变化规律,因此方程计算值能正确反映低频机械振动作用下不同振动频率、振动时间影响煤体孔隙率变化规律。

To study the influence of low-frequency disturbance load on gas porosity,the authors developed a porosity formula under coal porosity pressure, absorption strength and decreasing vibration stress. The authors adopted the change law of porosity and uniaxial compressive strength,and tested the uniaxial compressive strength changes of a sample under different frequencies and different vibrating time models. The test reveals that uniaxial compressive strength decreases and porosity increases when vibrating time extends under the low frequency and same frequency. When frequency decreases,uniaxial compressive strength increases and porosity declines. At the frequencies of 30 Hz and 20 Hz,the D-value of uniaxial compressive strength porosity is smaller than that at the frequencies of 20 Hz and 10 Hz. The test also demonstrates that vibration increases porosity and then decreases uniaxial compressive strength. Moreover,at the increasing frequencies of 10 Hz,20 Hz and 30 Hz,porosity gradually increases and uniaxial compres- sive strength decreases respectively. The calculated porosity reflects the variation of uniaxial compressive strength un- der vibration. The authors compared the relationship between calculation porosity and uniaxial compressive strength, and then obtained the class exponential change law of the former. The formula best reveals the different frequencies and time ranges imposed on the porosity changes under low frequency.

国家自然科学基金资助项目(51174157)；国家自然科学基金科学仪器基础研究专款资助项目(51327007)；

Li Shugang,Zhao Yong,Xu Mangui. Gas porosity formula under low frequency vibration and its testing analysis[J]. Journal of China Coal Society,2016,41(10):2612-2619.