Research on the Methods of Preventing Pressure Bump of Xinxing Coal Mine
Author:Shu Yan Min
Supervisor:ma nian jie
Coal rock burst is due to underground mining coal,and it make the redistribution of the situation of underground roadway surrounding pressure,reduced stress focus.When it reached a certain critical ratio,the system of mechanic balance is unstable,so,rock body is increasingly brittle damage,produce the power situation of abruptly,intensely damage.With the increasing of mining coal depth,the engineer index,like mining environment and the property of rock,...,will change greatly,mainly,higher underground pressure caused a series of deep force hazard,and the nonlinear phenomena,like the large deformations of surrounding rocks...Under the people disturbance,by the effect of coal mining,Concentrated stress by The Secondary Stress and Coal pillar,gob,geological structure...,made mining Environment worse off.the Physical and Mechanical Properties of coal is also the factor of contributing to Evoke Coal rock burst,secondly,outburst proneness of coal rock body is own property.Xingxin miner rock burst is different with the feature we saw,like Medium-Thickness Seam,medium hard coal and structure,which include the property of thin-hard seam,large inclined angle,the types of rock burst mainly include extension type rock burst by Hard Roof,partly,tectonic stress and fault.The paper discuss with practical subject conditions and the property of rock burst about xinxing miner,statistical rock burst on xinxing miner.The Analysis of cause,type,property and main Influencing Factors;developing the Prediction of the area of rock burst 、working face 、the design on xinxing miner;ensure preventive measures and mining design plans about rock burst;on the basis of the above,to predict and prevent rock burst,and The implementation in site,as to control the hazard of serious rock burst and decreased the effect of rock burst in site.By researching,we get:1.the analysis of Rock Burst Tendency of Coal-Rock and the Parameters of physic and mechanicTested by Rock Burst Tendency of Coal-Rock and the Parameters of physic and mechanic,Destruction of dynamic damage,according to the coal sample time,the elastic energy index and impact energy index,are comprehensive evaluation of six inclination of the impact of coal mining area 58 and 60 categories for three classes,which is namely as the strong impact tendency;According to the bending energy index of the rock;Judge 58,60 six mining area coal seam roof and floor rock impact bias categories are 2 class,is the weak impact bias.Through the bibulous rate of coal samples and the contact Angle test evaluation,identification of the coal seam water,injected to soften the rationality of reducing the impact of coal is dangerous.rock mineral water absorption and the contact Angle test results on xinxing miner show that the coal mine are 58 and 60 layer saturated water absorption rate and the contact Angle in the medium level,58 coal water absorption layer and the contact Angle test show that the suction effect is good at 60 layer,so you can consider in 58 layer water injection measures.2.The results analysis of ground stress field testDetermination the concentrated stress area within the well field region and the stress distribution is the premise of prediction and prevention for mining dynamic phenomenon.By the stress measurements and theoretical calculations,determined the concentrated stress area and the stress distribution within the area of Xinxing mine field,the measured value to the maximum level stress is the theoretical results above 5 times in Xinxing mine,Determine the level direction of the measured stress is more than twice the vertical direction,showing that the mine tectonic stress field behavior is very clear and the tectonic stress is major factor caused rock burst.So the design layout of mine development and mining in future,should fully consider the impact of tectonic stress and take reasonable design layout of mine development and mining,Advancing to decrease the potential possibility of impact.3.The mechanism analysis of rock burst in Xinxing mineStatistic the characteristics of rock burst in the Xinxing mining over the years,through analyzing on various aspects of the burst tendency of coal seam、mining depth、tectonic stress、gas pressure、hard poof and coal pillar etc,determined the main factors of rock burst in Xinxing mine,including the geological conditions and mining technology.The main factors affecting the Xinxing mining impact pressure are the strong impact tendency of 58 layer coal、60 layer coal in 6 mining area,medium impact tendency of the proof strata and floor strata,while the Xinxing mine’s mining depth has reached 500 m,reached the critical depth that rock burst occur.Due to the adjacent goaf,working face mining upper roadway always bear the pressure of same layer upper curtate adjacent goaf cantilever roof,upper roadway dip side coal is stress increasing area,the side of adjacent goaf is stress decreasing area,the stress concentration degree in coal near the upper and lower roadway is very difference.The upper adjacent goaf caused upper roadway dip side coal the stress concentration is a important cause of impact occursed.Leaving coal wall in the mining process lead the face upper end of adjacent goaf roof can not collapse in time,sandstone roof accumulate much elasitic energy,from the simulation results know that the abutment pressure on a wide range are in a high state of stress within the coal wall,Therefore,the upper end of the head near the working face is a high risk area and rock burst occur easily.Through statistical analysis,numerical simulation,theoretical analysis and field testing,Determine the impact of the Xinxing mining conditions and mechanism of the rock burst,the type of rock burst in Xinxing coal is stretch-type shock caused by ground-based hard roof,part of the dislocation type affected by tectonic stress and the impact of faults.4.Outburst area division in Xinxing mining faceBy analyzing work face mining conditions and mining factors,based on the pressure behavior law of gob-side entry retaining,the surrounding rock stress distribution characteristics of inclined coal seam mining face and roadway,determined the risk zone and high-risk zone in 41051 working face and 41062 working face,providing the theoretical basis for the 41051 and 41062 in the working face of normal production,and to strengthen support and monitoring in risk areas.5.Rock burst monitoring,prediction and analysis of electromagnetic radiation in the Xin xing mine working face.By monitoring the coal and rock under the action of external load of the deformation and failure process of electromagnetic signal strength,frequency,and the relation to the comprehensive analysis of tested area stress changes,and analyzing the possibility of rock bursts occurred.Through the use of KBD-5 and KBD-7 electromagnetic radiation monitor for monitoring mining working face,analyze the intensity of electromagnetic radiation in the high pressure concentration and the signal regularity of electromagnetic radiation during the first weighting and periodic weighting before and after.At the same time,the fuzzy pattern recognition method is used to determine the impact rock burst prediction critical value of electromagnetic radiation,evaluating the impact of working face dangers,the shock accidents are discussed in accurate predictions.Monitoring Area in Xin xing mine including:428 up-roadway,156 up-roadway,the field monitoring process,ensure long-term guidance and equipment maintenance,through monitoring for some time,mastering the regularity of electromagnetic response impact precursors and high-risk areas.6.The prevention and control measures in Xin xing mine high impact the danger zoneDrawing the following conclusions from simulating the 65 coal mining conditions in Xin xing mine: 63 coal,which is Liberated Seam,the floor of unloading damage depth is about 15 m,unloading depth in more than 30 m,after mining.65 coal and 63 coal spacing around 40 m,so,63 coal mining playing a role of stress liberation to 65 coal,but inadequate.In the process of mining in 65 coal,Away from the up roadway on the 10 ~ 30 m in working face in front of the 2 m range,there is a high stress concentration,mainly to Caused by superposition the trend abutment pressure and side abutment pressure.Moreover,remaining coal stack above the working face,making the upper roof hanging phenomenon is relatively serious.when hanging area is oversize,Very likely rock bursting.Mining the upon liberation,Coal mining for coal 67 will liberate to 65 coal.Due to the 65 coal floor damage depth after mining maximum 24 m,Unloading depth up to about 65 m,Roof and floor of 67 coal unloading effect;Mining the down liberation,67 coal mining damage height is much bigger than the floor damage depth,the pressure relief height is about 70 m,playing a very good role of liberation to 65 coal.For the specific circumstances of different measures are put forward,after the measures for risk prediction,to test the rationality and effectiveness of the measures.Xin xing mine mining face main measures of prevention and control of rock bursts are as follows: large diameter parallel drilling relief;coal unloading blasting,in the upper gate roadway on the end working face 20 m range,along the direction of dip Angle of coal seam cross drilling,coal unloading blast,gate roadway deep hole blasting,considering stress released totally,in the roof changes obviously before and after blasting,the blasting height can be determined according to 20 m.7.Mining design optimization scheme and treatment effect analysisFormulate the rock burst early warning,demolition and docimastic process of Xinxing Coal Mine.Since research work has been conducted,Xinxing Coal Mine actively takes the roof deep hole loose pre-blasting,coal seam pressure relief measures,at the same time in the part of the high risk area strengthening roadway support;by taking reasonable the various monitoring warning of the implementing scheme and rock burst demolition of danger and the control measures,greatly reduces the impact genetic times and the destructive range;along with the implementation of various control measures,the intensity of electromagnetic radiation value shows a decreasing trend,this shows that the risk of the occurrence of shock is also due to the implementation of measures to weaken.According to the basic characteristics of the Xinxing Coal Mine design and production conditions and rock burst occurrence,a preliminary study was carried out,from the mechanism of rock burst occurrence,monitoring and prediction and control technology etc,and some useful conclusions are obtained.But because of the complexity of the mechanism of rock burst in itself,and because of the limit of time and other factors,the paper still exist deficiencies,to study and improve the paper,in the future from the following several aspects to carry out the work:(1)This paper presents the mechanism of rockburst occurrence mainly from statistical analysis,theoretical research is discussed,in the future to test the correctness of the theory in practice,and to improve and supplement.(2)In this study,using the electromagnetic radiation method for monitoring mining work face,analysis of stress concentration region of electromagnetic radiation response,evaluation of the face of danger,but the method is evaluatedbased on the field monitoring,a certain lack of theoretical basis,and it only uses an evaluation method,adding other evaluation methods by comparative analysis,comprehensive will make the results more credible.