上盘预留矿柱回采过程中应力场演化规律研究

Research of Stress Field Evolution in the Exploitation Process of the Reserved Hanging Pillars

针对某金矿具有的缓倾斜、破碎、中厚矿体的特点,提出采用分段矿房法回采矿产资源;试验采场围岩总体稳定性较好,但矿体上盘边界是破碎蚀变带,岩石较破碎,而且矿区内地表水体较发育,上盘围岩中有含水层等特点。上盘围岩的冒落,对矿石贫化及安全采矿产生了很大影响,提出了预留上盘矿柱以减缓围岩冒落的方案。采用FLAC3D进行了回采过程中采场应力迁移、位移变化及单元破坏规律的数值计算研究。结果表明:预留2 m的矿柱有利于维持上盘的稳定性,防止塑性区域的扩大,从而达到降低矿石贫化及安全采矿的目的。

For the characteristics of slowly-inclined,broken, medium thickness ore-body,the sublevel room-pillar mining method is put forwards to exploit the mineral resources. In the test stope, the surrounding rock has a better stability, but the hanging wall boundary of the ore body lies in broken alteration zone with broken rocks. The surface water in the mine is devel- oped well, and there is s aquifer layer at hanging wall of the surrounding rock. The caving of the surrounding rock produces a great impact on the ore dilution and the safety mining. The hanging pillars are reserved to slow down the surrounding rock ca- ving. The FLAC3D is used to make numerical analysis on the stope stress migration, displacement and the destruction rule per u- nit. The results showed that the reserved 2 m pillars are beneficial to maintain the stability of the hanging wall, control the ex- tending of plastic zone, so as to lower the ore dilution and achieve the safe mining.