Studies On Relationship Between Microseism Time-Space Evolution And Ground Pressure Activities In Deep Mine

With the great demands of resource and energy by national economy rapid development, geological hazard problems induced by rock mass excavation during deep mineral resources exploitation become much more prominent. Because of the mechanical environment during deep mining is very complex, rock mass would be disturbed much strongly by excavation and blasting. It is extremely easy induced ground pressure disasters such as rockburst, which threatened the safety of mine personnel and equipment. At present, microseism (MS) technique has been widely used to forecast the dynamic disasters in mining, but the successfully predictions of pressure disasters are much fewer. The main reason is that most methods of microseism analysis are based on single criterion. It cannot discover the internal evolution laws form the microseism monitoring data that seemingly without rules and disordered. Therefore, it is very necessary to carry out studies on ground pressure disasters forecasting based on multi-parameters of microseism time-space evolution characteristics.In this dissertation, through rock uniaxial compression test, studies on microcracks time-space evolution regularity during rock fracture process and precursory features before rock failure were carried out based on acoustic emission (AE) located technique. Aimed at the serious condition of ground pressure appeared in Hongtoushan copper mine, Kaiser effect was used to measure the original rock stress, and conducted researches on the rockburst tendency in each level. On this basis, microseism system for deep ground pressure monitoring was established. The microseism data was long range transferred from Hongtoushan copper mine to Northeastern University. The analyzed methods of rock mass stability assessment and damage evolution by excavation based on MS and AE technique were completed. After that, studies on forecasting rockburst and large scale rock mass fracture by use multi-parameters were carried out. The main content of dissertation as follows:(1) Applied autoregressive model to estimate the arrival time of AE signals. Based that, an AE source located algorithm was introduced based on least squares algorithm and Geiger algorithm, and verified by using computer simulation, pencil break test and rock acoustic emission experiment. (2) Through rock uniaxial compression experiment, studies on evolution law of microcracks generation, propagation until cut-through based on acoustic AE located technique by using many theories such as fractal theory, b value and critical theory, etc. It specially analyzed the microcracks self-organization evolution process from disorder to centralized, the establishing process of stress field long range correlation and the precursory features before rock failure, which can provide theoretical foundation for rock mass stability monitoring in situ. Meanwhile, AE sources mechanism was discussed by use of moment tensor theory.(3) Carried out survey on deep ground pressure appeared condition and summarized the ground stress distribution law in Hongtoushan copper mine. Based on measured original rock stress by Kaiser effect principle, using many criteria to judge rockburst tendency in each level in Hongtoushan copper mine.(4) Established microseism system for deep ground pressure monitoring and realized microseism data long range transferred and real time analyzed. Through waveform recognition and spectrum analysis methods, a large number of interfering signals were filtered. Then, completely seismic data quantitative analysis method was established and researches on the relationship between MS time-space changed characteristics and mine production activities in Hongtoushan copper mine were carried out. Based on the foundation of rock acoustic emission studies, ground pressure prediction methods was established by using multi-parameters such as cumulative apparent volume, energy index, spatial correlation length, fractal dimension and b value, and so on.(5) Carried out motoring on blasting excavate process in deep stope based on AE and MS techniques by using the combined method of large scale monitoring and focal monitoring. The damage evolution regularity of surrounding rock before and after the excavation was studied. Through the AE and MS activity, stress field dynamic transferred law during excavation process was studied, and the time of surrounding rock return to stable state was specially analyzed. Through the researches of MS time-space evolution law and multi-parameters predicted method, the early warning period and dangerous period of ground pressure disasters are judged, and the studies on prediction of rockburst and large scale rock mass fracture were also carried out, which is used to guide safety production in Hongtoushan copper mine.