Research on rockburst prevention systems based on the attenuation law of coal and rock vibration wave energy.

During the coal and rock mass fracture process, elastic properties are released and vibration waves are radiated outward. The energy attenuation characteristics of these waves can describe the cumulative damage and elastic energy accumulation of the mass. To investigate coal and rock mass failure characteristics and energy attenuation rules during rockburst, numerical simulation and laboratory testing were utilized to study the energy transfer laws under various parameters. Six variables, including elastic modulus, Poisson's ratio, bulk density, cohesion, internal friction angle, and void ratio, were selected to simulate the rockburst energy release process under different parameter combinations by adding surface pressure to the model. The coal and rock mass energy attenuation coefficient was obtained by fitting the node energy straight line using the least squares method. The six variables' influence on vibration wave energy transfer was obtained using analytic hierarchy process program written in MATLAB, and a comprehensive calculation formula was proposed. Using the energy attenuation coefficient, the rock layer energy diffusion distance was calculated and compared with the roof collapse rock layer step distance, resulting in the roof rock layer cutting distance determination. By roof rock strata precutting, rockburst occurrence can be prevented, ensuring safe and efficient coal mine production.

Bursting Liability Criteria of Coal Mass Based on Energy Storage and Release Characteristics.

The bursting liability of coal, referring to the characteristic of coal to accumulate strain energy and produce impact damage, is an important factor influencing the occurrence and extent of rock burst disasters in coal mines. Two indicators-the elastic strain energy storage coefficient and energy release coefficient-are proposed based on the energy evolution characteristics of different stages during rock bursts. Twelve coal specimens from typical mines were selected for uniaxial compressive tests to analyze the damage characteristics of three types of typical coal specimens with different impact damage intensities in different loading stages. The initial kinetic energy of the coal specimens was obtained according to the principle of horizontal projectile motion. The bursting liability rating criteria according to the energy storage coefficient and energy release coefficient were determined based on the damage and motion characteristics of the coal mass, damage acoustic characteristics, and damage initial kinetic energy. The study demonstrated that the discrimination results based on the new criteria of coal mass bursting liability were consistent with the actual bursting liability level of the coal mass, thus providing a new method for determining coal mass bursting liability.

Numerical study on 4-1 coal seam of Xiaoming mine in ascending mining.

Coal seams ascending mining technology is very significant, since it influences the safety production and the liberation of dull coal, speeds up the construction of energy, improves the stability of stope, and reduces or avoids deep hard rock mining induced mine disaster. Combined with the Xiaoming ascending mining mine 4-1, by numerical calculation, the paper analyses ascending mining 4-1 factors, determines the feasibility of ascending mining 4-1 coalbed, and proposes roadway layout program about working face, which has broad economic and social benefits.