HIGH PRECISION LOCATION OF MICRO-SEISMIC SOURCE IN UNDERGROUND COAL MINE

Abstract

Accurate location of micro-seismic source in underground coal mine is of great significance for monitoring and early warning of dynamic disaster. Micro-seismic source information is generally extracted through inversion of the data acquired by the underground sensors. The installation of the sensors is limited around underground roadway. The unreasonable arrangement of sensors along the roadway will greatly decrease the precision of the seismic location. As for the ill-posed problems caused by the inversion for source location with sensor-received information, high precision location algorithm of micro-seismic source based on the arrangement optimization of monitoring points is presented in this paper. Firstly, the ill-posed problems are judged by calculating the coefficient matrix condition numbers. The ill-posed matrix is then pretreated by centralization and row balance jointly. The regularization parameters of pretreated matrix A and b are calculated by the L-curve method. The seismic source coordinates regularization solution is obtained via Tikhonov regularization algorithm. The research shows that the matrix magnitude is decreased hugely with centralization method, ill-posed condition numbers are reduced with row balance pretreatment. The minimum seismic source coordinate error of Tikhonov regularization solution after the pretreatment is 3.09 m which has been greatly decreased compared to the error by Gaussian elimination solution before the pretreatment. High precision seismic source location is realized in limited space of underground roadway by the above optimization processing.