Microseismic Signal Recognition And The Law Of Ground Pressure Disaster Microseism Precursor Research

Piaotang tungsten ore was a typical tectonic-stress mine,which influenced by regional fault, unbalanced exploitation and the large scale of goaf, the problems of ground pressure of which are relatively prominent. Stope rib spalling, caving and roof and floor deformation and fracture ground pressure events have occurred from time to time, therefore,the mine ground pressure disaster monitoring and forecasting has became the main job in the mining managerment. This dissertation relied on ground pressure microseism monitoring application technique research project in Piaotang tungsten ore, aiming at studying the microseism signal recognition, microseism activity law and ground pressure disaster forecasting which based on multi-parameters. The main research contents and results were as followlling:1. Lots of investigations were conducted into Piaotang tungsten mine, which including the current state of mining, the distribution of goaf and the main ground pressure concentrated area.Taking all these factors into account, this paper has constructed the Piaotang microseism ground pressure monitoring system and realized the monitoring of around-the-clock and real-time to the whole mine. And this paper has embodied the requirement for the positioning accuracy of the system design by conducting the artificial blasting experiment to calibrate the positioning accuracy of the system design.2. This paper has summarized the various Piaotang underground waveform signal characteristics to contribute to the artificial identification of the microseism signal. About the problem of the similarity between large-scale blasting events waveform and the maximum magnitude microseism events waveform, this paper has achieved striking identification effects by using spectrum analysis, wavelet-packet analysis and wavelet signal detection. The results show that : single-stage large-scale blasting signal frequency mainly distributes in the low frequency range between 0-30 Hz and the the maximum magnitude microseism signal frequency mainly distributes in the range between 30-50 Hz. In addition, this paper identifies these two signals by comparing between their characteristics of the mutation point.3. This paper has delineated the ground pressure events aggregation nucleation area and carried out the selective analysis through the active space-time distribution characteristic of the mine microseism.The variation regulation of the microseism event number in the nucleation area, the amount of the microseism energy released, energy index,apparent volume, the Schmidt number, b value and apparent stress seismological parameters, and that of microseism parameters can be used as the prediction of the precursory characteristics of ground pressure disaster. Using the Fourier Transform from thespectrum angle to analyze the precursor and the main shock signal waveform characteristics, combined with the analysis of wavelet packet energy distribution of microseism precursor and the main shock signal in distinct frequency bands, and using the characteristic of spectrum and of energy in the frequency band of microseism foreshock and main shock to forecast ground pressure disaster,which provide a new way to the forecast of ground pressure disasters. And this paper has established a ground pressure disaster forecasting model which is based on multi-parameters according to the precursor characteristics of each parameter.4. The linear weighted sum method was applied for calculation. Analytic hierarchy process method also applied for the weighs of prediction parameters calculation. Then ground pressure disaster forecast system containing various parameters was built. The predication of underground area would be achieved by this model in some activity spots. The result has shown that underground disaster coule predication by forecasting model.