平行四边形采场结构上行分段充填法的数值模拟

Numerical Simulation of Back Sublevel Fill Stoping with Parallelogramic Stope Structure

在分析分段充填法的应用现状及存在问题的基础上,以鲁中冶金矿业集团公司莱新铁矿为背景,综合考虑采场矿岩冒落特征,尽可能提高回采效率和爆破效果,避免采准巷道布置在充填体内等因素,提出了平行四边形采场结构的上行分段充填采矿方法,应用2D-σ有限元程序对其进行了数值模拟研究.研究结果表明:该方法在回采过程中不出现拉应力和较大应力集中,围岩应力周边分布均匀;回采后除下部充填体出现局部塑性区外,两边围岩及顶板不出现塑性区,说明莱新铁矿在破碎的厚大矿体中采用该方案是可行的.对比分析不同分段高度下围岩应力和塑性区分布,并考虑工艺要求,确定分段高度为10 m;考虑对相邻矿房回采的影响,提出充填体强度应在1 MPa以上的建议.

The current applications and problems of sublevel filling stoping in Laixin Iron Mine of Luzhong Metallurgic Group were discussed involving such factors as the natural roof caving characteristics of rock/ore at stopes, possible recovery ratio and blasting effect and avoidance of drift driving within fillers. A method of back sublevel filling stoping with parallelogramic stope structure is thus proposed, which is investigated numerical simulation using the 2D-σ software for finite element analysis. The results show that the tensile stress concentration and/or other high stress concentration in rock/ore will not occur in stoping process if applying the method proposed to mining, and the stress in surrounding rock is distributed uniformly along its periphery. And the plastic zone is not found in either wall on both sides of surrounding rock and roof except the filler bottom after stoping. The method is thus proved feasible to fragmentarily bulk ore body in Laixin Iron Mine. Analyzing comparatively the distributions of surrounding rock stress and plastic zones at different heights of sublevel with technological requirements taken into account, the sublevel height is determined to be 10m. In view of the stoping effect on neighboring rooms, it is suggested that the strength of filler should be over 1 MPa.