A coal seam roof stability evaluation method based on DAS microseism

Abstract

This invention relates to the field of coal mine microseismic monitoring technology, and provides a method for evaluating the stability of coal seam roof based on DAS microseismic monitoring. The method includes: S1: fiber optic cable deployment and data acquisition; S2: dividing the raw strain rate data into two parts: one part is used to extract low-frequency strain data (LF-DAS) through low-pass filtering; the other part is used to generate velocity data through velocity conversion; S3: microseismic event detection and candidate event screening; S4: first arrival picking and event quality control; S5: microseismic event location based on arrival time difference; S6: microseismic event attribute extraction; S7: borehole-fiber optic cable coupling quality evaluation; S8: roof stability feature construction; S9: roof stability risk index construction and classification evaluation; S10: roof risk deterioration trend determination and early warning output. This invention uses the strain rate data output by the DAS demodulator as a basis, constructs a dual-branch processing flow, and combines coupling quality correction and multi-index fusion evaluation to achieve quantitative evaluation and classification of the risk of roof failure in coal mining face roadways.

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