特大型采空区充填体强度设计优化

Design and Optimization of Backfill Strength for Super-large Goaf

为保证某矿特大型采空区的稳定性,最大程度回收采空区内的矿柱,采用工程类比法和理论计算法分别得出设计的充填体强度为2和1.5 MPa,根据设计强度得出灰砂比在(1∶4)^(1∶8),对充填体两侧进行受力分析后,应在采空区受力较大的顶底板处适当提高灰砂比,使设计充填体的抗压强度高于该处的实际受压强度,采用经验公式和杨辛公式进行充填体自立强度计算比较,得出40 m高充填体的设计强度为1.664 MPa。结果表明,3#矿体采空区最下部采用灰砂比1∶4胶结充填,然后逐步下降至灰砂比1∶8进行充填;在中段水平位置采用灰砂比1∶4胶结充填,充填高度不小于6 m;在距离采空区顶部2~3 m采用较高的灰砂比,甚至是水泥砂浆进行充填;可获取最佳的充填效果,保证矿山安全持续生产。

In order to maintain the stability of the super-large goaf and maximize the recovery of the pillar of a mine,by using engineering analogy method and theoretical calculation method,it is concluded that the design strength of 2 MPa and 1.5 MPa.According to the designed strength,the ash-sand ratio is between(1∶4)^(1∶8),after the stress analysis on both sides of the backfill,the ash-sand ratio should be appropriately increased at the roof and floor with large stress,so that the compressive strength of the designed backfill is higher than the actual strength.Empirical formula and Yangxin formula are used to calculate and compare the self-supporting strength of backfill,and the design strength of 40 m high backfill is 1.664 MPa.The study results show that the floor of No.3 ore body goaf is filled by cement with a sand-lime ratio of 1∶4,and then it gradually drops to a sand-lime ratio of 1∶8;in the middle section,the ash-sand ratio is 1:4 and the filling height is not less than 6 m;in the roof 2~3 m,a higher ash-sand ratio or even cement mortar should be used.Therefore,the best filling effects can be obtained,safety and sustainability production of the mine can be guaranteed.