Application of acoustic logging in elastic mechanics analysis of coal and rock

The elastic mechanical properties of coal and rock are important parameters for the stability analysis of coal seam roof and floor, which is the base for coal mine safety and green mining. As the degree of coal mining and the depth of coal seams increase, it is prone to accidents over the top and bottom plates, thus affecting the safe production of in mines. In the past, the method of obtaining rock mechanics parameters through core test had the disadvantages of data dispersion, high cost and long period, which couldn't meet the needs of production. Based on the analysis of borehole logging and core mechanics test data, the relationship between sonic logging and rock mechanics parameters is explored, and the mathematical model for calculating the parameters of elastic mechanics is established. The relative error verified by verifying boreholes was only 0.9%, indicating that the calculation of mechanical parameters by sonic logging is credible, and the rock mechanics profile can be established quickly and continuously. According to the results of rock mechanics calculation, the mechanical properties of the top and bottom rock of the main coal seam of coal mines are studied. The stability evaluation criteria of the floor were evaluated for the stability of the coal seam roof. The results show that the top and bottom of the main coal seams in the mining area are mainly siltstone, fine sandstone and sandy mudstone. Most of the coal seam roof is unstable type Ia. The coal seam floor is mostly soft IIIb, and the stability of coal seam roof and floor is not good; the hardness of the top and bottom of the main coal seams is quite different, most of the Platts coefficient is less than 6, and the excavation is good, which is suitable for large-scale and mechanized mining.