“应力-渗流-损伤”分析下的煤柱宽度设计

Design of “stress-seepage-damage”analysis width of section coal pillar

大南湖一矿3#煤层上覆岩层属于Ⅳ,Ⅴ类岩层,节理裂隙发育,遇水易软化破碎。1301工作面与1303工作面的区段煤柱为18 m,导致巷道破坏严重。为探究合理的区段煤柱宽度,基于岩石损伤的"应力(stress)-渗流(seepage)-损伤(damage)"理论,采用fish语言编程对Flac3D软件计算过程中的岩石力学参数进行优化,实现软件在计算过程中水对岩石的损伤作用。在此基础上,进行富水条件下区段煤柱宽度优化"应力-渗流-损伤"分析下的数值模拟分析,揭示不同宽度煤柱内部应力演化特征、损伤区域分布以及底板渗流通道。结果表明:区段煤柱宽度在18~22 m时,煤柱内部应力为42~52 MPa,应力集中明显;煤柱下部裂隙贯通,煤柱内部弹性核范围不足高度的2倍;本区段合理煤柱宽度为26 m,下区段合理煤柱宽度为30 m,既保证安全生产又保证经济效益。并通过现场实测验证了下区段30 m煤柱的可靠性,对以后富水条件下的煤矿安全开采具有一定的指导意义。

The overburden of No. 3 coal seam for Da Nanhu mine belongs to Ⅳ,Ⅴ rock,joint fissure development,water softening and broken easily. 1301 working face and the 1303 working face section pillar is 18 m,resulting in destruction of roadway. To explore the reasonable width of coal pillar in the section,based on the rock damage theory of ＂stress-seepage-damage＂,using fish language of Flac3 D,we optimized the calculation of rock mechanics to realize the software in the calculation of water in the process of rock damage,and conducted the optimal numerical simulation of the coal pillar under the condition of rich water section,analysis of evolution characteristics of section return air lane and internal stress of the coal pillar under different width coal pillars,and the regional distribution of internal damage of coal pillar and floor seepage channel. The results show that,the section width of coal pillar is 18 - 22 m,the internal stress of coal pillar 42 - 52 MPa with obvious stress concentration; Crack at the bottom of the coal pillar is cutthrough,internal elastic core range is less than 2 times the height of the coal pillar; the section reasonable coal pillar width should be 26 m,next section＇s reasonable width of coal pillar is 30 m,which is not only safety in production but also guarantee the economic benefit,and verified by field measurement the next section＇s 30 m pillar is reliable. It has certain guiding significance to coal mine safety mining under the condition of rich water.