膨胀性充填体物理力学特性演化规律研究

Study on the Evolution of Physical and Mechanics Characteristics of Expansive Cemented Paste Backfill

充填采矿方法中充填采场的接顶效果是矿山进行安全高效开采的重要保证,充填体充填后存在一定沉缩现象,导致接顶效果不好,成为矿山安全开采的严重隐患,膨胀剂的添加为解决充填体的接顶问题提供了新的思路。为了解决江西某钨矿充填体主动接顶问题,本研究选取发泡剂、静态破碎剂和混凝土膨胀剂为膨胀剂,综合考虑质量浓度、灰砂比和膨胀剂掺量的影响,分析不同类型膨胀剂情况下充填体的膨胀率和单轴抗压强度演化规律。结果表明,充填体的膨胀率均随膨胀剂掺量的增加呈现出增加的趋势,但充填体的单轴抗压强度却随膨胀剂掺量的增加呈现出减小的趋势。不同类型膨胀剂膨胀效果排序为:发泡剂>静态破碎剂>混凝土膨胀剂,强度下降显著性排序为:发泡剂>静态破碎剂>混凝土膨胀剂。静态破碎剂既能保持良好的膨胀性,充填体的强度下降幅度也相对较小,选择静态破碎剂作为该矿山充填体膨胀剂。研究结果也可为同类矿山安全开采提供借鉴。

In filling mining method,the effect of roof-contact technology is an important guarantee for the safety and efficient mining.The mining of two-step stope is significantly affected by the roof-contact technology of filling body for the one-step stope,which becomes an important hidden danger for safety mining.In this study,the expansion rate and evolution patterns of uniaxial compressive strength of backfill under different types of expansion agents were analyzed by selecting foaming agent,static crushing agent and concrete expansion agent as expansion additives,and the influence of mass concentration,cement to tailings ratio and expansion agent content were considered.The results show that the expansion rate of the backfill increases with the increasing dosage of the expansion agent,whereas the uniaxial compressive strength of the backfill exhibits a decreasing trend.The expansion effect of different types of expansion agents is as follows:Foaming agent>static crushing agent>concrete expansion agent,and the order of strength decline is as follows:foaming agent>static crushing agent>concrete expansion agent.Therefore,static crushing agent was able to maintain good expansibility while causing a relatively small decrease in the strength of the filling body.The research results can provide technical support for selecting reasonable expansion agent in Xianglu tungsten mine,and it can also provide certain reference for similar mines.