Analysis of support resistance distribution and rapid increase resistance effect in deep buried thin bedrock panel with large mining height

The Panel 14030 of Zhaogu No.2 coal mine is a typical deep buried thin bedrock panel with large mining height. As the roof weighting occurs, the support resistance increases rapidly, and the dy⁃ namic load impact occurs at times. In order to improve the control effect of deep buried thin bedrock roof, theoretical analysis, field measurement and numerical calculation are used to analyze the support resistance distribution and rapid increase resistance effect of large mining height working face. It is found that the average working resistance of the support in the middle of the panel is significantly larger than that of the upper and lower supports, and the middle roof exists a risk of dynamic load impact. The roof at both ends of the panel is seriously broken, and the support resistance is low, but it is easy to cause the problems such as forward inclination and collapse of the support. The rapid advance leads to a significant increase in the working resistance of the support during the pressure period, an increase in the number of dynamic load shocks, and a relaxation of pressure during the non⁃pressure period. In the slow advance stage, the load transfer of the slow advancing roof is sufficient, the stress time of the support is long, and the roof damage is serious, which leads to the short pressure step and the weakening of the dynamic load impact effect of the roof. The resistance⁃increasing cycle curve of the support is divided into three stages. The middle support of the panel has obvious resistance⁃increasing characteristics in the first stage and the third stage, indicating that the initial support force of the middle support of the panel is insuffi⁃ cient, and the roof pressure is large, and the pressure is fast, and the dynamic load impact phenomenon is prone to occur. The instability process of the composite bearing structure of the caving arch and the high rock beam at the arch foot is the main reason for the rapid increase of the resistance of the support in the middle of the panel. Through numerical simulation analysis, it is proposed that when the support stiffness is maintained at 50 MN / m, the dynamic load impact of the roof can be alleviated, so that the support can yield pressure in time, and the displacement of the support can be controlled to the greatest extent to ensure the stability of the coal wall in the stope. © 2023 China University of Mining and Technology. All rights reserved.