遗留煤柱回采围岩破坏特征及地表变形规律研究

Surrounding rock failure characteristics and surface deformation law under mining of retaining coal pillar

针对榆神府矿区旺格维利采煤遗留煤柱回采围岩稳定性及地表变形控制难题,提出窄条带式胶结充填、连采机回采旺格维利采煤遗留煤柱方法,开展了胶结充填材料物理力学特性测试,采用FLAC 3D模拟分析及地表沉陷预计,研究了不同遗留煤柱回采尺寸下采场围岩塑性区、采场应力演化规律及地表变形规律。研究表明,遗留煤柱回采尺寸为14 m时,采场煤柱塑性区破坏严重,最大垂直应力达19.60 MPa;遗留煤柱回采尺寸为6 m时,采场煤柱塑性区发育范围减小,应力峰值仅为11.6 MPa;工作面充填开采区域越小、充实率越大,地表变形影响程度及范围逐渐减小,当充实率为95%时,地表最大下沉值仅为46 mm,充填可有效控制岩层移动,实现水源保护区下保水采煤。

Aiming at the problems of stability and the surface deformation control of the surrounding rock under mining of remaining coal pillar by Whangavelli method in Yushenfu mining area,we propose a narrow strip cementation filling method and a continuous mining machine mining the remaining coal pillar by Whangavelli,and test the physical and mechanical properties of cemented filling materials.The plastic zone,stope stress evolution law and surface deformation law of the surrounding rock under different mining sizes of retaining coal pillar are studied by FLAC 3D simulation analysis and surface subsidence prediction.The results show that when the mining size of the remaining coal pillar is 14 m,the plastic zone of the stope coal pillar is seriously damaged,and the maximum vertical stress reaches 19.60 MPa.When the mining size of the remaining coal pillar is 6 m,the development range of the plastic zone of the coal pillar in the stope is decreased,and the stress peak was only 11.6 MPa.The smaller the filling mining area of working face,the larger the filling rate,resulting in the gradual decrease of the surface deformation influential degree and range.When the filling rate is 95%,the maximum subsidence value of the surface is only 46 mm.The filling can effectively control the movement of rock formations and realize water-conserving coal mining under the water source protection zone.