Development characteristics of the rock fracture field in strata overlying a mined coal seam group

Abstract

The fracture development of the overlying strata after coal mining is an important guarantee of efficient gas drainage. In order to explore the fracture evolution characteristics close to a mined coal seam group, the F15.16−24130 working face in the Pingdingshan No. 10 coal mine was taken as the research background. The FLAC3D numerical simulation software was used to study the migration and failure characteristics of the overlying strata during mining of a coal seam group, and the fracture evolution process of the stope was investigated. The results show that as the advancing distance increased, the fracture density and fracture height increased continuously due to deformation and failure of the overlying rock. The displacement of the overlying rock initially increased and then decreased, and the displacement of the floor rock initially decreased and then increased. When working face F15.16 of the coal seam advanced to 75 m, a saddle-shaped plastic zone gradually formed in the upper part of the goaf and the floor of the goaf was formed. The pressure relief depth was proportional to the advancement distance. As the advancement distance of the working face increased, the pressure relief depth gradually extended to the F17 coal seam, which was conducive to the development and penetration of the fractures in the coal floor and rock mass and was convenient for pressure relief gas drainage from the F17 coal seam.

Study on prevention and control mechanism of runoff water hazard in thick coal seam mining in valley terrain

“…To solve the problem of roadway water inrush and water conservation mining caused by the development of fracture zones (Zhang and López, 2019;Xie et al, 2021;Chen et al, 2022), Xie obtained five development stages of the waterconducting fracture zones. Besides, previous studies have shown that different mining methods (Du and Gao, 2017;Zhou and Yu, 2022), mining parameters (Wang et al, 2020;Qi et al, 2022) and repeated mining of coal seams (Tian et al, 2019;Cheng et al, 2020) also affect the development height of water-conducting fracture zones. Based on a large number of engineering practices, different numerical analysis models (Zhang et al, 2017;Zeng et al, 2022), mechanical theoretical models (Ning et al, 2020;Zhu et al, 2020;Yang et al, 2021;Tan et al, 2022) and monitoring methods (Wang et al, 2016;Mondal et al, 2020) have been successively introduced into the prediction and exploration of the height of water-conducting fracture zones.…”

Research on the coupled support technology of a composite rock beam-retained roadway roof under close coal seams

“…When plastic deformation continues to develop into plastic damage, the floor deformation peaks, and a continuous slip surface is formed within the floor (Cheng et al, 2021b). According to the theoretical analysis of the floor slip field (Zhang et al, 2012;Sun et al, 2021;Zhang et al, 2021;Qi et al, 2022), the maximum depth of impact on the floor after mining of the upper coal seam can be calculated by the following equation:…”