Research on Effect of Roof Breaking and Pressure Relief Based on Blasting Energy Analysis

In order to verify the blasting roof breaking and pressure relief effect, taking the deep hole blasting roof breaking technology adopted by Jining No.3 Coal Mine to solve the stress concentration in low-level key layers as the background, based on the dynamic-static load action, through the early fracturing of key layers, the deformation energy is released to reduce the intensity of stress concentration, and the blasting roof breaking effect research is carried out according to the blasting induced energy. Taking the average value of unit energy of 8 times of blasting in the undisturbed area (424 J) as the basic energy (E₀), combined with data from two working faces, the methods of regional division and main influencing factors are adopted to analyze and obtain the multiple relationship between the blasting induced energy (E) and the basic energy E₀ under a single key factor (such as the coal pillar area E being 3 times that of E₀), and summarize the multiple reference values. In view of the limitations of traditional stress monitoring and single point analysis of fissure observation method, a multi-factor coupled energy multiple evaluation system is established, by comparing the ratio judgement effects of the actual E multiple and the reference values, a difference of ≤ 20% is considered good, while a difference of ≥ 50% is considered poor. This system realizes the regionalization and multi-factor comprehensive evaluation of the blasting roof breaking effect.