露天开采下伏采空区顶板控制研究

1.金属矿山安全技术国家重点实验室,湖南 长沙 410012; 2.长沙矿山研究院有限责任公司,湖南 长沙 410012

露天开采; 采空区; 顶板控制; 数理分析; FLAC3D

Research on goaf roof control under open pit mining
LI Zhen1,2,CHU Hong-tao1,2,WANG Yu1,2

(1.State Key Laboratory of Safety Technology of Metal Mines,Changsha 410012,China; 2.Changsha Institute of Mining Research Limited Liability Company,Changsha 410012,China)

open pit mining; goaf; roof control; mathematical analysis; FLAC3D

DOI: 10.13800/j.cnki.xakjdxxb.2015.0307

备注

以柿竹园多金属矿490矿区为工程背景,采用数理分析方法,推导出露天开采下伏采空区稳定的顶板极限厚度公式,并用FLAC3D软件及现场数据对公式结果进行验证。结果 表明:采空区顶板竖直方向主要受剪切应力影响,水平方向主要受侧向围岩拉、压应力影响; 随着露天采剥作业的进行,采空区主要竖向应变方向由散体沉降导致的向下位移发展成为由散体内部向临空面方向; 当开挖超过顶板极限厚度,顶板自身强度无法继续抗衡两侧围岩产生的应力,应力应变变化速率迅速增大,顶板失稳; 通过与现场数据进行比较,证明数理分析得出的顶板极限厚度公式是合理的。

With the background of 490 ore district in Shizhuyuan multi metal mine,using the methods of mathematical analysis,infer the formula of limit thickness of goaf roof,then verifies the results of formulas using software FLAC3D and monitoring data.The results show that:Goaf roof is mainly affected by the effect of shearing stress in vertical direction,and mainly affected by the surrounding rock stress effect in horizontal direction; With the open pit stripping operations,goaf main vertical strain direction changes from downward displacement caused by settlement into free surface; When excavating over the limit thickness of roof,the roof self strength cannot continue to compete on both sides of surrounding rock stress,the change rate of stress and strain increases rapidly,then goaf roof changes into instability.The results prove that the formula of limit thickness of goaf roof through mathematical analysis is reasonable with important reference value to isolation roof thickness optimization and site construction of similar mines.