Study on long-term stability of downhill protective coal pillars in deep mines based on Burgers model
DUAN Zhichao
HUANG Gang
YUAN Lei
YU Zhoulei
Abstract：The protective coal pillars in the downhill sections of deep mines are long-term in a complex environment of"three highs and one disturbance"(high stress,high water pressure,high ground temperature and excavation disturbance),and their cumulative creep damage effect significantly affects their long-term stability.Traditional design methods based on static assumptions are diffi-cult to meet engineering requirements.Taking the north No.3 mining area of Yangcheng Coal Mine as the engineering background,aiming at the long-term stability problem of downhill protective coal pillars,a numerical analysis method based on the Burgers creep model is proposed.Five groups of comparative tests were conducted to calibrate the parameters of the Burgers model,revealing the calibration laws of each parameter of the Burgers model on the instantaneous creep deformation,initial creep rate,and stable strain,and verifying the consistency between the numerical simulation results of coal samples and the laboratory creep test results(the max-imum error<3.5%).based on the FLAC3D numerical simulation software to construct a geomechanical model,this study integrates theoretical calculation,static simulation and creep analysis to compare the widths of downhill protective coal pillars in the mining area when the time effect is not considered,including the"three unders"mining(mining under buildings,railways and water bod-ies)specification method(56.3 m),the limit equilibrium theory(53.7 m)and the Mohr-Coulomb elastoplastic model(58.8 m),fur-thermore,the Burgers model is introduced to analyze the creep characteristics of coal pillars.The simulation results show that within the 10-year service period of the protective coal pillar,creep of the coal pillar causes the in-situ stress boundary to migrate toward the roadway.The distance between the final mining line of the working face and the stress boundary increases from 58.8 m to 72.3 m,the horizontal displacement remains basically stable after 3 years,and accumulated displacement during the creep period is approx-imately 70 mm.Considering the influence of advance abutment pressure and the cumulative effect of creep damage comprehens-ively,the reasonable width of the downhill protective coal pillar in the north No.3 mining area is finally determined to be 75 m.
Keywords：protective coal pillarlong-term stabilityBurgers modelcreep characteristicnumerical simulation
Publication Date：2026-02-20
Online Publishing Date：2026-03-19(First online date of this platform, not the publication date of the document)
Pages：12( 177-188 )