Abstract: Mine earthquake is a local regional rock layer vibration caused by underground mining work, which has the characteristics of being localized and highly harmful. It not only affects the economic benefits of increasing production in mines, but also easily causes varying degrees of damage to nearby aboveground structures. As the mining progress continues to increase, the displacement trend caused by it on the overlying rock layer gradually shows a certain regularity. Studying and mastering the laws of mining earthquake events and the impact of mining earthquakes on surface subsidence under various factors is of great significance for the study of mining earthquake activities.

This paper mainly uses theoretical analysis and statistical analysis of measured data to comprehensively study the impact of mining earthquake events on surface subsidence based on long-term leveling observation data. Combined with the relevant mining earthquake event data statistics of Dongtan Coal Mine 6306 working face from 2020 to 2022, it analyzes the movement law of overlying rock caused by mining earthquakes, the spatiotemporal distribution characteristics of mining earthquake positions and maximum subsidence points, the energy level of mining earthquakes, the law of surface subsidence at the depth of the earthquake source, as well as the statistical analysis results of the changes in surface subsidence rate within a period of one to half a month before and after the occurrence of mining earthquake events from both qualitative and quantitative perspectives, are studied to investigate the correlation between subsidence rate and mining earthquake. This provides a predictable decision-making method for the occurrence of mining earthquake events and helps to establish a prevention mechanism for mining earthquake.

The rules and conclusions obtained in this article using the above analysis methods and technical means are as follows:

(1) The movement pattern of the overlying strata in the goaf: As the mining process progresses, the continuous expansion of the goaf area causes displacement of the overlying strata on the working face. At the same time, due to the impact of mining earthquake events, surface settlement also increases. In 2020, the range of surface settlement was X=400-1600m, with a maximum settlement value of 2.3m; In 2021, the range of surface subsidence moved forward, at X=600-1600m. Considering the situation where multiple mining earthquakes caused the overlying rock structure to stabilize, the maximum subsidence value was 1.2m; In 2022, the range of surface subsidence is X=1200-1600m, with a maximum subsidence value of 1.3m.

(2) The spatial relationship between surface subsidence and mining earthquakes: When a mining earthquake occurs, it will cause significant changes in surface subsidence near its location, resulting in sudden changes in subsidence values, with a maximum subsidence value of approximately 1m. Most cases occur in subsidence basin areas.

(3) The mutation of surface subsidence rate and the occurrence law of mining earthquakes: The occurrence of mining earthquakes will cause sudden changes in nearby surface subsidence values and subsidence rates; According to the statistical analysis of multiple measured data, in general, there is no significant change in surface subsidence. The subsidence value is within 20mm, the subsidence rate is less than 5mm/d, and the increment of subsidence value is basically maintained at -2-4mm/d; Before and after the mining earthquake, both the settlement value and settlement rate underwent a sudden change, with a maximum settlement value exceeding 1m and a settlement rate greater than 5mm/d, reaching a maximum settlement rate of 17mm/d.

Keywords: mining earthquake, overlying rock movement pattern, surface subsidence amount, subsidence rate