Research on evaluation and control technology of coal pillar stability based on the fracture digitization method

In order to master the instability mechanism of coal pillar, the method of coal pillar fracture digitization was improved, and the ``basic measurement scale-borehole comprehensive parameter method" which can realize the evaluation of a complex fracture network was proposed. The evaluation results indicate that the coal pillar failure exhibits obvious zonal characteristics and the damaged coal pillar can be divided into the stripping area, the yield area and the load-bearing area. In light of the characteristics of coal pillar failure and the limit equilibrium theory, the model of coal pillar stability evaluation was established. Furthermore, the model was used to evaluate the stability of coal pillar in Baodian Coal Mine. The safety factor is 1.54 which meets the current requirement for safe production. Meanwhile, according to the model of coal pillar stability evaluation, measures for controlling coal pillar stability, namely roof pre-cutting, re-anchoring, and long and short injection, were proposed. (C) 2020 Elsevier Ltd. All rights reserved.