Study On The Characteristics Of Shock And Instability Of Isolated Panel And Rockburst Prevention By Liquid CO₂ Cracking

Rockburst is one of the most serious disasters in the process of underground coal mine mining.Many mining areas existed different forms of isolated panels in China,more and more rockburst occurred in the isolated panel and coal pillar,and the disastrous damage caused by rockburst became more and more serious.It is an urgent trouble to solve the problem how to mine isolated panel safely and efficiently and improve the coal recovery ratio.Therefore,study the characteristics of shock and instability of isolated panel and make reasonable technical scheme of rockburst prevention have great significance to solve the problem of rockburst.The paper takes isolated panel 8939 of Xinzhouyao mine in Datong mining area for example,applies the comprehensive method of theoretical analysis,numerical simulation,laboratory experiment,field test and underground survey to carry out research work of isolated panel rockburst prevention.The paper put forward to an evaluated method of geological dynamic conditions of coal mine,and analyzed the geological dynamic conditions of rockburst about Xinzhouyao mine.The distribution characteristic of rockbust in the neighboring goaf was statistic and analyzed by microseismic evens,the mechanical parameter and outburst-proneness of coal was test in the laboratory.Based on the elastic plate theory and elastic mechanics,the instability characteristics of coal-rock mass and the energy characteristics of hard roof were analyzed,studied the characteristics of shock and instability of isolated panel.Rockburst comprehensive evaluation model of CW-TOPSIS was used to judge the weight of rockburst factors,and analysis rockburst strength of isolated panel.The paper simulated the mining of isolated panel and adjacent panel by FLAC^3D numerical simulation software,analyzed the energy characteristic before and after mining the isolated panel and the plastic failure force of coal pillar.The paper comprehensive evaluated the measures of rockburst prevention,determined the conventional prevention measures and put forward new measure which is suitable for isolated panel.The paper studied the mechanism of liquid CO₂ cracking,tested the cracking parameters by self-developed equipment,and carried out filed test in Xinzhouyao mine.The distributed optical fiber sensing technology and borehole peeping equipment were used to monitor the effect of liquid CO₂ cracking.According to the different risk areas,making comprehensive prevention scheme to control rockburst of isolated panel,and using microseismic monitoring and on-line monitoring of hydraulic support to predict rockburst and test the effect of rockburst prevention.The research results determined the geological dynamic conditions of rockburst about Xinzhouyao mine,revealed the characteristics of shock and instability of isolated panel,predicted the dangerous area of isolated panel.A new rockburst prevention method of liquid CO₂cracking was put forward,and it had been well applied in the field.The technical scheme of rockburst prevention was worked out in this paper.The results have important theoretical significance for deep understanding the characteristics of shock and instability of isolated panel,provide a new approach for rockburst prevention,improve the effectiveness of prediction and prevention for rockburst,guarantee the safe mining of isolated panel,and provide the practical value for similar coal mines.