Spatio-temporal evolution characteristics of overburden stress and fracture in fully mechanized caving face of extra-thick coal seam
QIAN Sifa
YANG Juan
LUO Junbo
LIU Yongliang
SUN Chunhui
Abstract：The high-intensity disturbance of fully mechanized top coal caving mining in extra-thick coal seam is easy to cause dramatic changes in overburden stress and fracture development,resulting in disaster risks such as roof water disaster and rock burst.Aiming at the problem of overburden stress and fracture development in 2302 fully mechanized caving face of Zhaoxian Coal Mine,this study uses field investigation,numerical simula-tion and other methods to analyze the stope stress,overburden deformation and failure of extra-thick fully mechanized caving face,and systematically discusses the overburden deformation and stress evolution law under the influence of working face length during the mining of extra-thick coal seam fully mechanized caving face.The results show that:After the mining of the 2302 working face,the internal stress of the solid coal and rock mass in front of the working face is concentrated,and the goaf is in the form of'arch',accompanied by the stress reduction area;In the early stage of mining,the face length has no obvious effect on the roof deforma-tion.After the first weighting,the roof deformation of the stope begins to show an increasing trend.When the face is longer than 250 m,the growth rate of the roof deformation of the stope increases rapidly.When the working face length is less than 250 m,the development height of the plastic zone does not affect the water-bearing thick medium conglomerate layer.When it is greater than 250 m,it begins to affect the water-bearing thick medium conglomerate layer until the plastic zone develops to the surface.When the length of the working face is longer than 250 m,the influence range of the abutment stress influence zone and the separation zone of the coal wall increases rapidly.The study reveals the critical influence law of working face length on the stabili-ty of overburden rock in extra-thick fully-mechanized caving face,which has important guiding significance for controlling the development height of water-conducting fracture zone,preventing roof water inrush and rock burst disaster,and optimizing the safe mining parameters of fully-mechanized caving face in extra-thick coal seam.
Keywords：extra-thick coal seamnumerical simulationstope stressoverburden rock deformation and failureevolution of the three horizontal zones
Publication Date：2025-08-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 11-20 )