Effects of different geo-stress on two-phase flow dynamics of coal-gas outbursts in true triaxial stress state
ZHOU Bin
YANG Zhaolong
LI Shugang
XU Jiang
CHENG Liang
LIN Haifei
SHUANG Haiqing
HU Biao
Abstract：To further investigate the mechanism by which in-seam geo-stress influences the disas-ter-causing effects of coal-gas outburst two-phase flow in roadways,physical simulation experi-ments of outbursts under different geo-stress conditions were conducted.The disaster-causing characteristics of the two-phase flow during outbursts were analyzed,including impact dynamics,movement,and pulverized coal accumulation-sorting.The results show that the frequency of im-pact force pulses shows a decreasing trend as the distance from the outburst mouth increases.The peak impact force in the near outburst mouth area is positively correlated with geo-stress.As dis-tance increases,the attenuation of the peak impact force accelerates,with a notably lower decay rate under high geo-stress conditions.The disaster-causing zone of impact dynamics within the roadway exhibits a discontinuous distribution,primarily concentrated in the middle-front sections.The highest risk period occurs between 600 and 2 000 ms after the outburst.The harmfulness of impact dynamic disaster-causing in the roadway shows a trend of first increasing and then decrea-sing with increasing geo-stress,and decreases significantly under high geo-stress.It indicates that when the geo-stress increases to a certain level,a suppression mechanism for disasters caused by two-phase flow impact dynamics will be generated.The speed of outburst shock waves ranges from 330 to 400 m/s,approximately 10 to 15 times faster than the pulverized coal flow.During the outburst process,the pulverized coal concentration in the area near the outburst mouth chan-ges at the fastest rate,and the higher the geo-stress,the greater the pulverized coal concentration.With the increasing geo-stress,both the total mass of pulverized coal after outburst and the pro-portion of small and medium-sized particles increase,which both enhance the outburst intensity and exacerbate pulverized coal fragmentation.The peak value of crushing work migrates backward along the roadway with the increase of geo-stress,and the amplitude tends to increase.The accu-mulation and crushing energy of pulverized coal is mainly concentrated in the middle of the road-way.
Keywords：coal and gas outbursttwo-phase flowgeo-stressimpact forcemovement charac-teristicspulverized coal accumulation
Publication Date：2025-09-30
Online Publishing Date：2025-10-31(First online date of this platform, not the publication date of the document)
Pages：14( 1053-1065,1111 )