Joint Bearing Mechanism of Coal Pillar and Backfilling Body in Roadway Backfilling Mining Technology

In the traditional mining technology, the coal resources trapped beneath surface buildings, railways, and water bodies cannot be mined massively, thereby causing the lower coal recovery and dynamic disasters. In order to solve the aforementioned problems, the roadway backfilling mining technology is developed and the joint bearing mechanism of coal pillar and backfilling body is presented in this paper. The mechanical model of bearing system of coal pillar and backfilling body is established, by analyzing the basic characteristics of overlying strata deformation in roadway backfilling mining technology. According to the Ritz method in energy variation principle, the elastic solution expression of coal pillar deformation is deduced in roadway backfilling mining technology. Based on elastic-viscoelastic correspondence principle, combining with the burgers rheological constitutive model and Laplace transform theory, the viscoelastic solution expression of coal pillar deformation is obtained in roadway backfilling mining technology. By analyzing the compressive mechanical property of backfilling body, the time formula required for coal pillar and backfilling body to play the joint bearing function in roadway backfilling mining technology is obtained. The example analysis indicates that the time is 140 days. The results can be treated as an important basis for theoretical research and process design in roadway backfilling mining technology.