Solution To Seismic Source Mechanism Of Surrounding Rock And Seismicity Response To The Mining In Dongguashan Copper Mine

Recently, many mines of China have gradually embarked on the deep mining. Impact ground pressure, rock burst, deformation and fracture of the roof and floor, pillar instability and mine accidents occur frequently, besides, the associated seismicity have become more and more serious. Therefore the research of seismicity has very important practical value and scientific theoretical significance. Seismicity signal recognition, seismicity source mechanism inversion and source type, and mining induced seismicity response to mining were researched based on the research projects of Dongguashan Copper Mine. Main research contents and results are as follows:(1) The source signal recognition which is the key technology of the underground mine was researched. For non-interference seismic signal, a detailed instruction on the type of signal source and the classification of all kinds of the characteristics of the signals are given by using the artificial recognition method; The theory of wavelet was used in the analysis of strong interferenced seismic signals, which proved that the wavelet analysis is a very good tool to unsteady signal; Matlab wavelet toolbox was used for the signal wavelet transform and noise reduction processing of the strong interferenced seismic signal monitored by Dongguashan Copper Mine seismic monitoring system. The results show that the wavelet analysis has a good recognition effect and signal denoising ability.(2) Seismic source mechanism solution of the deep rock failure is inverted through the seismic wave form and system monitoring data. According to the seismic wave information, the initial p-wave dynamic displacement field radiation pattern can analysed with the use of JMTS calculation software, then, the seismicity source mechanism solution of surrounding rock failure were obtained; The moment tensor expression was decomposed into isotropic and anisotropic part. Therefor the equivalent point source model was obtained according to the decomposition form. The expression of focal mechanism solutions were discussed according to the magnitude of the intrinsic values. Three surrounding rock damage source models were summarized combined with the seismicity source mechanism solutions of deep rock failure and the surrounding environment of Dongguashan Copper Mine.(3)The different period seismicity and the response characteristics of the mining were compared through the cumulative seismic apparent volume (ΣVA) and energy index (EI). The cumulative excavated volume and cumulative seismic apparent volume time history curve were established to study the mining rate and seismic strain rate relationship; With a view to energy storage and release, the ratio of the cumulative apparent volume (ΣVA) to the cumulative volume of production (ΣVm) was defined as coefficient of seismic response to mining(CSR) to present the relationship between energy storage and energy release in rock mass. The variation of CSR indicates the tendency of stability of rock mass system, which can be easily used in analysis of mine seismicity monitoring and as a good guide parameter to control mining rate.