拱效应对狭窄型充填采场内应力分布状态的影响

摘要

The vertical stress reduction ratio by arching effect in narrow backfilled stopes was calculated by FLAC software,and the conversion rate between arching effect and horizontal stress of backfill under different internal friction were compared,and influence of filling times on stress state in backfill was also discussed.The results show that,backfill vertical stress tends to be stable with depth increase due to arching effect,and vertical stress at the bottom of backfilled stope represents just 42.26％ of gravity of the overlying backfill.The backfill with internal friction of 15°,30°,and 45° correspond to a level of horizontal stress conversion rates of 51.55％,57.74％,and 69.07％ respectively.And filling times plays an insensitive role in arching effect and stress distribution state in backfill.The strength design of backfill in narrow stope should take the conversion of vertical stress by arching effect into consideration,for reducing the related technical and economic index.%利用FLAC研究了拱效应对狭窄型采场内充填体垂直应力的降低比率,对比了不同内摩擦角下充填体内的拱效应及水平应力的转化率,讨论了回填次数对充填体应力分布状态的影响.结果表明:拱效应的存在使充填体内的垂直应力随着深度的增加而逐渐趋于稳定,采场底板处的垂直应力仅为其上覆充填体自重的42.26％;充填体内摩擦角分别为15°、30°和45°时,对应的水平应力转化率分别为51.55％、57.74％和69.07％;回填次数对充填体内的拱效应及应力分布状态影响甚微.狭窄型采场内的充填体强度设计应考虑拱效应对垂直应力的转化作用,从而降低相关技术经济指标.