Study on the manifestation law of mine pressure in double-channel working face of multi-positioned thick roof plate

The complex geological structure of coal mine has an important influence on the appearance law of mine pressure in working face mining, which seriously restricts the safe and efficient mining of coal resources. In order to study the causes of roadway bottom drumming in Buertai Coal Mine, and reveal the law and mechanism of mine pressure manifestation in double-channel working face of multi-positioned thick roof, this paper constructs physical and numerical models of double-channel working face mining of multi-positioned thick roof, studies the dynamic change process of overburden displacement and breakage in the process of double-channel working face mining, and reveals the law of surrounding vertical stress distribution, the law of vertical stress evolution of coal pillar, and the law of energy evolution of surrounding rock in the process of mining in working face, and analyses the law of energy evolution of 12-upper 302 auxiliary transportation roadway. It reveals the distribution law of vertical stress in the surrounding rock, the evolution law of vertical stress in the coal pillar and the evolution law of energy in the surrounding rock during the working face mining process, and analyses the cause of the bottom drum of the roadway in the auxiliary transport tunnel of 12-upper 302. The results of the study show that: the initial pressure step of 12-upper 301 working face is 55 m, the cycle pressure step is about 8.2 m, and the average rock fall angle is 53.4°. The subsidence movement of overburden rock is controlled by the roof plate of multi-positioned thick layers. When advancing within 60-240 m, the subsidence process of each rock layer before the roof plate of the median thick layer breaks down is shown as the stage of emergence of off-layers and increase of off-layers, and the overburden rock sinks rapidly as a whole after the roof plate of the median thick layer breaks down. During the advancing process of 12-upper 301 working face, the vertical stress peaks in front of the working face and in the vicinity of the adjacent coal pillar increase significantly, which is closely related to the breakage of the overlying multi-positioned thick roof plate, and the maximum stress concentration coefficient is 3.6, and the vertical stress of the adjacent coal pillar reaches the maximum value of about 21.09 MPa at about 250 m behind the working face, and the energy accumulation is easy to be formed in the area of the front of the working face and the adjacent coal pillar, and the peak energy density is up to 55.0 MPa, and the peak energy density is up to 55.0 MPa. The peak energy density reaches up to 55.3 MJ/m³. The roadway of the 12-upper 302 auxiliary transport tunnels is directly affected by the deformation and breakage of the thick roof plate, which generates stress concentration and energy accumulation in the adjacent coal pillar, and eventually leads to the occurrence of the bottom drumming phenomenon in the roadway. This study can provide theoretical basis for mine pressure management in mines with similar conditions.