Surrounding rock failure characteristics and influencing factors in large-section roadways subject to mining-induced pressure

YAN Dezhong

doi:10.11799/ce202601019

Abstract：To address the challenges of controlling surrounding rock in high roadways subjected to mining-induced pressure,we took the 3924 return air roadway of Zhaiyadi Coal Mine as the research subject.Numerical simulation was used to analyze the influence range of mining pressure on the heading roadway,as well as the distribution characteristics of the plastic zone and maximum shear strain in the surrounding rock during different mining-excavation stages.Based on the shear-block theory of the roadway side coal mass,a mechanical model was constructed,and an expression for calculating the safety factor of the side coal mass was derived.After substituting actual parameters,the influencing factors on roadway stability were systematically analyzed.Combining numerical simulation and theoretical analysis,support parameters for the surrounding rock in the mining-affected section were designed and implemented in a field industrial test.The results show that the influence range of mining stress extends 40～60 m ahead of the heading face,and the distribution of the plastic zone closely aligns with that of the maximum shear strain.The shoulder and floor corners of the roadway sides are the initiation zones for shear failure.Under the superimposed stress from mining and heading,an X-shaped shear-slip zone forms in the pillar side within the mining-affected section,dividing the coal mass into an unstable triangular block.This block slips under the combined action of mining pressure and self-weight,leading to rib spalling,with mining pressure being the direct trigger for activating the shear-slip surface on the pillar side.Roadway height is negatively correlated with side stability,while coal strength and support resistance are positively correlated with side stability.Field monitoring data indicate that after implementing the proposed support scheme,deformation of the surrounding rock in the mining-affected section is limited,and the overall support effect is satisfactory.This study can provide a reference for surrounding rock control in roadways under similar conditions.