Abstract:

Rock burst is a dynamic disaster that occurs during coal mining, characterized by the sudden and violent release of elastic deformation energy accumulated in coal and rock. The majority of rock bursts, approximately 90%, happens in roadways. Roadway impact failure is not only influenced by impact energy, but also by the distance from the impact source. To address this, the concept of energy distance ratio is introduced, which represents the ratio of energy released by the impact source to the distance to the roadway. By considering the static load superposition mechanism of rock bursts and the balance theory of impulse energy absorption, various factors are taken into account, including the characteristics of the impact source energy distance ratio, roadway failure degree, energy absorption of supporting components, and energy absorption of weak structures. Based on these considerations, a corresponding relationship between the energy level of rock bursts and roadway support strength is established. The roadway support technology based on “four high anchor mesh +” is determined, which includes the use of high-strength anchor mesh combined with other support elements. The safety and reliability of roadway support technology under rock bursts are classified into P1-P4 levels according to the energy distance ratio of the impact source. Each level corresponds to the “four high anchor mesh +” combined support technology with different support strength. The research findings suggest that “four high” anchor mesh support is suitable for non-impact roadways with energy distance ratios in the magnitude of 10² rock bursts. “Four high anchor mesh +1” combined support, which includes O-shaped steel sheds, energy absorption and anti-impact unit frames, and weak surrounding rock structures, can prevent 10³ magnitude rock bursts. “Four high anchor mesh +2” combined support is effective against 10⁴ magnitude rock bursts, while “four high anchor mesh +3” combined support can prevent 10⁵ magnitude rock bursts. Rock bursts with magnitudes of 10⁶ and above require remote treatment and removal from production. Engineering examples are provided to demonstrate the anti-impact support scheme and parameter design of roadways. These examples help verify the feasibility and practicality of the theoretical research results. The research outcomes have valuable implications for the theoretical research and engineering practice of rock burst roadway support in coal mines in China.

Key words: rock burst, roadway surrounding rock control, impact absorption energy balance, ratio of energy to distance, graded support