巨厚松散层下煤层开采的抗渗透性破坏和煤柱安全性研究——以口孜东矿为例  

RESISTANCE TO PERMEABILITY DAMAGE AND PILLAR SAFETY OF COAL MINING UNDER GIANT THICK LOOSE SEAM--TAKE KOUZIDONG MINE AS AN EXAMPLE

作　　者：丁甲 董东林[1] 胡志强 张陇强 张百伟 DING Jia;DONG Donglin;HU Zhiqiang;ZHANG Longqiang;ZHANG Baiwei(China University of Mining and Technology(Beijing),Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)地球科学与测绘工程学院,北京100083

出　　处：《工程地质学报》2021年第4期1071-1083,共13页Journal of Engineering Geology

基　　金：国家自然科学基金(资助号:4197020829)。

摘　　要：随着深部煤炭资源的枯竭,浅部煤层上巨厚松散层水体成为淮南矿区不可忽视的安全隐患,预留煤柱的安全性评价显得尤为重要。本文以口孜东井田为例,通过全面系统地收集整理口孜东矿近年来井上、下补充探查、矿井水动态长期观测、井下采掘工程揭露的地质和水文地质资料,通过数值模拟和理论分析方法得出以下几点认识。(1)以矿区经典块段的钻孔柱状图为依据,建立基于FLAC3D的力学模型,按步长模拟工作面回采,通过观察分析位移云图、最大主应力图、塑性破坏图来认识开采覆岩破坏规律并分析导水裂隙带高度约为56.6 m,导水裂隙带无法发育至含水层高度;(2)根据口孜东矿的水文地质资料,建立基于GMS(Groundwater Modeling System)的水文地质模型,采动引起的覆岩弯曲变形导致了其垂向渗透系数和水力梯度发生变化,将FLAC3D中采动对模型产生的应力影响作为依据,将应力大小转化为弯曲带的垂向渗透系数作为变量在GMS模型中体现出来,校核模型准确性并观察开采前后的渗流场变化,发现渗流场产生的变化非常微小,也保证了留设煤柱的安全性;(3)分析涌水溃砂的控制因素,结合矿区抽水试验数据,利用计算机建立迭代计算程序,计算四含与红层的临界水力梯度分别为Jcr四含=1.66、Jcr红层=1.62,得出各个点位的临界水头高度取值范围在10~25 m之间,远低于实际水头值,从抗渗透性破坏方面评价了煤柱的安全性。目前在含水层下开采煤层时防水煤柱的留设依据主要是采高、煤层倾角、顶板岩性及其力学性质等因素,而未考虑含水层的水理性质及其在渗流场发生变化后的改变,亦未考虑基岩风化层的上述性质,本文通过对巨厚松散层下开采的覆岩破坏规律、含水层渗流场变化及抗渗透性破坏的联合研究,为评价煤柱的安全性提供了科学的方法和依据。With the shift of coal seam mining from deep to shallow,the water-bearing bodies of huge thick loose layers covering the coal seams have become a safety hazard that cannot be ignored in Huainan mine area.So the safety evaluation of reserved coal pillars is particularly important.This paper takes the Kouzidong mine as an example,presents the comprehensive and systematic collection and collation of geological and hydrogeological data revealed by long-term observation of mine water dynamics and underground mining works in Kouzidong mine in recent years.It uses the numerical simulation and theoretical analysis methods and obtained the following findings.(1)Based on the borehole column diagram of the classic block section in the mine area,a FLAC3D based mechanical model is established to simulate the workface retrieval by step.The displacement cloud diagram,maximum principal stress diagram and plastic damage diagram are observed and analyzed to recognize the mining overburden damage law.The height of the hydraulic fracture zone is about 56.6 m.The hydraulic fracture zone cannot be developed to the height of the aquifer.(2)According to the hydrogeological data of Kouzidong mine,a hydrogeological model based on GMS(Groundwater Modeling System)is established.The bending deformation of the overburden rock caused by mining lead to the changes in its vertical permeability coefficient and hydraulic gradient.The stress effect of mining on the model in FLAC3D is used as the basis.The stress magnitude is transformed into the vertical permeability coefficient of the bending zone as a variable reflected in the GMS model.The accuracy of the model is checked and the changes in the seepage field before and after mining is observed.It is found that the changes in the seepage field are very small,which also ensures the safety of leaving the coal pillars.(3)The control factors of water gushing sand is analyzed.The mine pumping test data is used.The iterative calculation program is developed using computer.The two critical hydraulic gra

关 键 词：导水裂隙带 临界水力梯度 安全煤岩柱 渗透性破坏 

分 类 号：TD82[矿业工程—煤矿开采]