Henan Provincial Key Lab of Gas Geology and Control-Cultivation Base of Provincial and Ministry Joint State KeyLab Henan Provincial Collaborative Innovation Center of Coal Safety and Production MOE Engineering and Research Center of Mine Disaster Prevention and Rescue

为研究煤体注氮增透对液氮溶浸下饱水煤裂隙的扩展规律,从王营子矿取立方体原煤煤样,真空饱和后开展液氮溶浸试验,测试了液氮溶浸前后煤样的声速、代表性裂隙面积变化率和煤样表面微观结构的变化,推导了液氮作用下饱水裂隙内水相变为冰的冻胀压力,建立了液氮溶浸下饱水煤裂隙煤扩展的力学判据。结果表明:1液氮溶浸下煤内裂隙水相变为冰,体积膨胀,引起煤内裂隙扩展,代表性裂隙面积增长,超声波速降低,裂隙密度增加。煤的微观结构也发生了很大变化。2建立的力学判据准确预测了煤样的裂隙扩展。3随着裂隙长短轴长度比值的减小,冻胀压力增加,随着水流出系数增加,冻胀力线性减小。

in order to reveal the difusion features of the gassy coal in the negative pressure environment the tifusion and desoption processes of the gassy coalwere sinulated underthe regative pressure environnent of 0,10.20,30 and 40 k Pa in the lab and a comparison anal sis was conducted on the gas descorption volum.desorption rat .dfifision rale and difuision ceicient unde a fferent negative prssure environment. The resuits showed that the gas desopton volume would be steadly increased with the environment pressure increased,the accumulated desorpton volume within 360 minutes would be increased by 37.45% in max and the negativeprssure would have a role to pronoe the gas desorption of the cal. Belore the frst 15 minutes.the negative pressure would have obvious infuences to the gas desorption rate especall ould have a max infuence to the gas desorption rate within the frst three minutes,the attenuation was about 60% and arer the frst15 minuesthe negative pressure would have less infuences to the desorption rate.Under the samecondtin of desopton balanced rssure.the gas di.fison coe Fice nt and th dtffusion c.eficient would all be increased with the negative pressure increased. The negative pressure increased would cause the dfision c eicient inreased and would be the main factor to promote the gas desorption.

国家自然科学基金资助项目(51274079；51574139；51304108；51274110)；