浅部矿体开采覆岩运移及导水裂隙带发育高度分析

Analysis of Overburden Migration and Development Height of Water-Conducting Fracture Zone in Shallow Orebody Mining

为研究浅部矿体开采覆岩运移及导水裂隙带发育特征,以红柳矿I020308工作面为研究对象,采用理论试验、数值模拟、理论研究与现场实测方法,分析采动覆岩运移规律以及导水裂隙带发育高度。结果表明:1)覆岩裂隙呈“采场上方裂隙扩张-采空区上方裂隙闭合”趋势,岩块破断呈“下位岩体垮落-上位岩体咬合-叠层同步下沉”趋势,覆岩下沉量峰值达3.268 m。2)导水裂隙带高度发育过程为极缓慢-逐步扩展-迅速发育-增速递减发育;伴随采动影响,含水层水量间歇性释放,采空区涌水量交替增-减且整体呈下降趋势,直至工作面充分采动后稳定,实测导水裂隙带高度为58 m。3)基于矿物成分及微观结构分析,覆岩内富含亲水性黏土矿物且广泛分布粗颗粒,水-岩反应下将加剧裂隙发育,造成理论与实测导水裂隙高度形成误差。

In order to study the migration of overburden rock and the development characteristics of water-conducting fissure zone in shallow orebody mining,taking Hongliu Mine I020308 working face as the research object,theoretical test,numerical simulation,theoretical research and field measurement methods were adopted to analyze the migration rule of overburden rock and the development height of water-conducting fissure zone.The results show that:1)The overburden fracture presents a trend of"crack expansion above the stope-crack closure above the goaf",and the rock block fracture presents a trend of"caving of the lower rock mass-interlocking of the upper rock mass-synchronous subsidence of the stack",and the peak subsidence of the overburden rock reaches 3.268 m.2)The height development process of the water-conducting fracture zone is very slow-gradual expansion-rapid development-decreasing growth.With the influence of mining,the aquifer water is released intermittently,and the water inflow in the goaf increases or decreases alternately and shows a downward trend on the whole until the working face becomes stable after full mining.The measured height of the water-conducting fissure zone is 58 m.3)Based on the analysis of mineral composition and microstructure,the overlying rocks are rich in hydrophilic clay minerals and widely distributed coarse particles.Under the water-rock reaction,the development of cracks will be intensified,resulting the error between theoretical and measured height of water-conducting cracks.