Gas extraction roadways layout based on evolution of overburden fracture field induced by mining

XIE Jun

doi:10.11799/ce202509019

Abstract：In view of the large amount of gas emission from adjacent strata and the gas overrun in the upper corner of Sijiazhuang Coal Mine,the goaf was divided into four zones based on the key stratum theory.Utilizing 3DEC numerical simulation,the collapse process of the overburden was analyzed from the perspective of the velocity field,thus to identify the key strata,divide the"four zones"for pressure-relief gas extraction,monitor the displacements at various levels within the goaf,examine the porosity distribution characteristics,and reveal the extent of fracture development areas in the goaf.Employing digital image processing technology,the characteristics of fracture distribution within the goaf were quantitatively analyzed.It was determined that the dominant rich accumulation areas for gas extraction in the fault zone extend from 25 m to 77 m within the boundary of the working face,at the height range of 44～63 m.The collapse zone was identified as the area from 3 m to 44 m inside the working face boundary,with heights ranging from 5.5 m to 25 m.Considering the geological features of the gas,the movement patterns of the overburden,and the requirements for gas extraction,optimal positioning for the layouts of high and low extraction roadways was proposed.After field application,effective gas management results were achieved through these high and low extraction techniques,with concentrations of gas in the upper corner maintained below 0.8%.