Study On Precursor And Information Fusion Early Warning Of Gassy Coal-rock Burst Failure

Along with the increase of mining depth and mining intensity, high stress and highdensity of gas have made the rock burst disaster more and more critical and complex.In allusion to gas-containing out-bursting coal seam, considering the actionmechanism of gas to coal mass rock burst, multiple forewarning information gas,stress, AE, EMR, microseism etc. are fused together for effective rock burst earlywarning, which has great theoretical and practical significance for the study of rockburst mechanism of gas-containing coal seam, and for the improvement of rock burstprevention technology of coal mining. Therefore, a triaxial gas-containing coal androck loading and breaking forewarning information experiment system is built in thispaper, and by using the experiment system, real-time synchronization testing ofparameters like EMR、 AE、 gas during the loaded and fractured process ofgas-containing coal mass is realized. Both gas emission laws and the features offorewarning information like EMR、microseism(AE)、gas、stress in the process ofgas-containing coal seam bursting are studied and analyzed. Based on the D-Sevidence theory, a multi-forewarning information fusion system and method ofgas-containing coal seam bursting is built and tested and verified with fieldexperiments. The main research results in this paper are as follows:(1) The triaxial gas-containing coal and rock loading and breaking forewarninginformation experiment system is researched and built, which could synchronouslytest parameters like EMR、AE、gas、stress、strain and so on while coal samples beenloaded and broken under conditions of different confining pressure and gas pressure.In the experiment, mechanical characteristics and change laws of parameters likeacoustic-electronic signals、gas pressure of coal and rock breaking under the conditionof different confining pressure and gas pressure are studied. The results show that: thefracture load value of coal sample keeps decreasing with gas pressure increasing, andincreasing with confining pressure increasing. The acoustic-electronic signals increasein both amount and intensity with the loading pressure rising, and gas pressure andemission load increase suddenly at the loading peak value.(2) Based on acoustic-electronic characteristic parameters, coal and rock damageevolution model which considering residual strength is built, and used to study thecorresponding relation between acoustic-electronic signals and coal and rock deformation and breakage.(3) A coal and rock mass permeability-damage coupling evolution model whichconsidering the gas adsorption and expansion is built, and it reveals the internalmechanism of abnormal gas emission of the instability while gas-containing coalseam bursting, which proposing that the gas could act as a forewarning indicator ofgas-containing coal seam bursting and instability. Combining monitoring data ofEMR、microseism(AE)、gas emission and mining stress which tested before thebursting, the forewarning information change laws of gas-containing coal seambursting and instability are revealed.(4) According to the multi-forewarning information, the forewarning indicatorsystem of gas-containing coal seam bursting is built, and the determination methodsof critical values of different indicators are ascertained. Based on the indicator systemand the D-S evidence theory, a kind of information fusion forewarning model andmethod is proposed and tested and applied in field experiments. The results show that,with rock burst event coming closer, the rock burst criticality changes from risk-freeto medium risk to high risk, i.e. the risk rate increasing gradually; the accuracy rate ofrock burst risk early warning is high and there is no missing report.