Mechanical characteristics of coal pillars in complex-structure coal seams and optimization of roadway surrounding rock stability
Niu Haiping
Pan Ruikai
Yu Weidong
Shen Yuxu
Wu Shaokang
Abstract：Objectives To address the problems of severe roadway surrounding damage and poor stability during mining of complex-structure coal seams,the failure mechanism of coal pillars under roadway stress was investigated,taking the 10103 face of Baozigou Coal Mine as a case study.Methods Field measure-ment,mechanical analysis,numerical simulation,and field tests were employed to investigate the mechani-cal characteristics of coal pillars in complex-structure coal seams and to develop optimization strategies for roadway surrounding rock stability.Results A theoretical calculation formula for coal pillar size in complex-structure coal seams was derived,and the optimum roadway-protective coal pillar width was determined to be 5.66～7.04 m.It was revealed that the plastic zone depth of coal pillars under mining influence is 2.8 times that of conventional coal seams,confirming the regulatory effect of interlayers on the stress redistribu-tion process of surrounding rock.The evolution laws of vertical stress,vertical displacement,horizontal stress,and horizontal displacement were clarified,and a coal pillar width of 7 m was found to effectively enhance roadway surrounding rock stability,verifying the theoretical results.Field application of the opti-mum pillar size showed remarkable improvement in roadway conditions before and after implementation.Conclusions Increasing coal pillar width enhances bearing capacity,but excessive width leads to stress concentration on the goaf side,endangering overall stability.The results provide significant guidance for the rational design and application of coal pillars in complex-structure coal seam mining,offering new theo-retical and practical references for the field.
Keywords：complex-structure coal seamcoal pillar sizemechanical modelstress evolution lawsurrounding rock stability
Publication Date：2025-11-30
Online Publishing Date：2025-10-22(First online date of this platform, not the publication date of the document)
Pages：9( 118-126 )