【作者】 常剑；

【导师】 叶海旺；

【作者基本信息】 武汉理工大学 ， 采矿工程， 2010， 硕士

【摘要】 论文简述了我国铁矿石的需要状况,分析了我国矿山开采的发展趋势,同时针对一类难采矿体—缓倾斜薄矿体,总结了开采该类矿体时所使用的采矿方法,其中,房柱采矿法所占的比例最高。鉴于此,本文以房柱采矿法为例,对采场进行简化后,利用相关力学理论对顶板及矿柱稳定性进行了分析,得到了采场中各物理量的分布规律。然后利用有限差分软件FLAC3D,针对水平矿体的开采,建立了两种采场结构模型：(1)考虑到铲运机能在相邻矿房间来回作业,将矿柱间距固定为4m。(2)矿房跨度与矿柱间距尺寸相等；分别对以上两种结构形式的采场进行了数值模拟,比较了在同样回收率条件下,顶板中最大拉应力值的大小,并选较小拉应力的结构形式进行后续分析。本文选取第二种采场结构模型并进一步对其进行数值模拟,分析了矿岩物理力学性质、地应力、采场结构参数对房柱法采场稳定性的影响,得到如下结论：(1)选取了两种力学性质差别较大矿岩进行了数值模拟,发现采场中各物理量分布的差别不大,但矿岩自身的力学性质的限制影响了开采的安全性。(2)对于地应力对采场安全的影响,通过数值模拟得出：采场周围较大的水平侧向应力对维护顶板中央的稳定性有利,垂直应力(赋存深度)的增大导致了顶板中最大拉应力的增加以及矿柱平均垂直应力的线性增长,加速了顶板和矿柱的破坏。(3)采场结构参数的影响主要表现为：矿房高度对采场顶板的稳定性基本没有影响,同时矿柱平均压应力随高度的增大仅有微弱的增大,但对矿柱稳定性的影响主要体现在矿柱支撑能力的变化上,因为矿柱高度的增加降低了矿柱的支撑能力(尺寸效应)；矿房跨度的增大时,顶板最大拉应力增大,且增加幅度越来越大；在矿房跨度较小时,矿柱宽度的变化顶板最大拉应力基本上没有影响,但在跨度较大时,增大矿柱宽度能降低顶板最大拉应力。最后,针对鄂西缓薄高磷赤铁矿,通过数值模拟,得到了不同深度下的采场最优结构参数,并计算得到了矿石回收率,进而通过线性回归得到回收率随深度变化的函数关系。更多还原

【Abstract】 Demand status of iron ore in our country is briefly stated in this paper, and development tendency of domestic mining is analyzed, meanwhile, mining methods used to mine gentle dip thin ore which can’t be easily mined are summarized, among which the proportion of room-and-pillar mining method is highest. In view of this, taking the mining method for example, related mechanics theory is used to analyze the stability of roof and pillar after the simplification of stope, and the distribution rule of each physical quantity(stress, displacement) is obtained. Then two forms of stope structure of horizontal ore are established with FLAC3D, a finite difference software in the paper:(1) Considering that carry-scraper can make a round work in adjacent stope, the pillar gap is fixed as 4m,(2) Room span is equal to pillar gap.Then numerical simulation of the two forms is conducted respectively, making a comparison of the maximum tension stress in roof in the condition of the same recovery, and the smaller one is chosen for following analysis. The second form are selected for further numerical simulation. Then the influence of physical and mechanical properties of ore and rock, geo-stress, stope structure parameter to the stability of stope is analyzed respectively, and the results are shown as following:(1)Two kinds of ore, the mechanical properties of which are greatly different, are chosen for numerical simulation in the paper, the results of which shows that the physical quantities slightly vary, but the mechanical properties of ore itself influence the safety of mining.(2)For the influence of geo-stress to stope safety, it can be drawn from numerical simulation that high horizontal stress around the stope is favorable to sustain the stability in the center of roof, the increase of vertical stress (depth) leads to the increase of maximum tension stress in roof and the linear increase of pillar average vertical stress, which accelerates the break of roof and pillar.(3)The influence of stope structure parameters mainly can be concluded as:there is little influence of the room height to stope roof, at the same time, along with the increase of depth, there is a little increase in average stress of pillar. But to the influence of pillar stability, it mainly reflected in the variations of pillar supporting capacity, because the increase of pillar height decreased pillar supporting capacity (size effect). The maximum tension stress increases with the room span and the increasing range become larger. When the room span is small, there is little influence of width of pillar to the maximum tension stress, but when the span is big enough, increasing the width can decrease the maximum tension stress of roof.Finally, aiming at gentle inclined thin ore body in Western Hubei, using numerical simulation, optimum structure parameters and ore recovery are obtained, then the functional relationship between recovery and depth is gained.更多还原