Research On Rock Burst Prevention And Control Technology Of Deep High Stress Face In Yuanzigou Coal Mine

At present,with the increasing mining depth of coal resources,the danger of rock burst is getting higher,which has become one of the major disasters in Shaanxi and Mongolia coal producing areas.The establishment of the first anti-impact system of working face in Yuanzigou Coal mine is of great significance to ensure the safe mining of working face and the establishment of rock burst system.Based on the 1012001 deep high stress working face in Yuanzigou Coal mine,this thesis studies the risk factors,potential mechanism and type of rock burst in 1012001 working face through theoretical analysis,engineering analogy,statistical analysis and engineering practice,and establishes the monitoring,warning and prevention technology system of 1012001 working face.Based on the actual data on site,effectiveness analysis and index optimization of monitoring,early warning and prevention measures were carried out,and the following conclusions were drawn:(1)Through theoretical analysis,the risk factors of 1012001 working face are determined as follows: mining depth,physical and mechanical properties of coal and rock,roof strata characteristics,folding structure,bottom coal thickness and coal pillar in sections;Based on the difference of correlation between each risk factor and microseismic distribution,the influence degree of each risk factor was determined.Finally,the 1012001 working face was divided into four regions by coupling superposition of different risk factors,and the main controlling factors of each region were analyzed and determined.(2)Based on the analysis of stress concentration of geological structure,roof and floor characteristics and other factors,it is determined that the whole working face is in static load environment,and the stress concentration degree of coal pillar,hole cutting,stop-mining line and other areas is more obvious.It is determined that there are 6 key layers in the roof of1012001 working face based on the theory of key layer and key layer of impact inducement.When the roof of working face is hard and complete,the high medium-grained sandstone layer(main key layer)is the key layer of impact inducement.When the roof integrity of working face is poor,the low fine-grained sandstone layer(subkey layer 1)is the key layer of impact inducement.Based on the theory of static and dynamic load superposition,the potential rock burst generation type of 1012001 working face is determined to be "high static load-low dynamic load" type.(3)Based on the actual engineering conditions,a multi-element early warning system of cuttings,stress and microshock was constructed.Based on the actual monitoring data and the field pressure situation,the effectiveness of the early warning value was analyzed.It was found that the index values of cuttings,stress monitoring and microshock early warning were all high and the warning index item and warning level were single.Statistical analysis method was used to optimize the warning index,and the monitoring and warning system of drilling cuttings subsection warning,stress online classification warning and microearthquake multi-item classification warning was established.(4)Based on the mechanism analysis results and the actual conditions of the mine,a prevention and control technology system based on large-diameter drilling and supplemented by roof hydraulic fracturing was designed.The effect of the pressure relief measures was analyzed through the field monitoring data and the optimized early warning index.It was found that the pressure relief measures could effectively reduce the regional stress concentration and the overall pressure relief effect was good.For the area with poor pressure relief effect and to prevent the high stress area that may appear in the mining process of working face,the measures of large-diameter borehole reinforcement and pressure relief,coal body blasting,floor deep-hole blasting and roof deep-hole blasting are designed to form a pressure relief control system of 1012001 working face,which is based on large-diameter borehole pressure relief,supplemented by roof hydraulic fracturing and coal rock blasting.This thesis has 70 figures,30 tables and 101 references.