【作者】 王戈；

【导师】 朱川曲；

【作者基本信息】 湖南科技大学 ， 安全技术及工程， 2009， 硕士

【摘要】 在环境与能源问题日益突出的今天,煤炭开采日趋环保化,煤炭绿色开采理念正是在此基础上提出来的。煤矿常规开采方法引起地表沉陷严重;煤矿开采产生的矸石量大,占地污染严重;正在自燃的矸石山,如遇到雨水的渗入,受热后空气急剧膨胀,会引起爆炸,造成更大的危害,必须对煤矸石进行综合治理;把煤矸石、灰渣等废弃物充填到井下,进行充填开采,是解决煤矿常规开采方法引起的地表沉陷,处理和利用煤炭开采产生的各种废弃物行之有效的方法。另外,我国煤矿“三下”压煤量巨大,随着相当一部分矿区的煤炭资源逐渐枯竭,“三下”压煤的开采是很多矿区将要面临的问题,对于压煤现多数矿井采用充填开采。因此,充填开采条件下采空区的瓦斯运移成为了目前面临的一个问题。在国内外,纯粹研究采空区瓦斯运移规律已经有很多成果,但在充填条件下采空区瓦斯运移的研究还很少。在充填开采势在必行的今天,开展充填开采条件下采空区瓦斯运移研究具有很重要的意义。本论文针对充填开采条件下采空区瓦斯运移问题,在查阅国内外大量综采工作面充填开采技术研究文献和采空区瓦斯涌出及运移分布研究文献的基础上,借助岩石力学、流体力学、瓦斯渗流理论、多孔介质渗流理论及相关理论,运用理论分析、物理数学建模分析、计算机仿真技术等手段,研究U型和Y型两种矿井通风系统下充填煤矸石、灰渣和泥沙三种充填物对采空区瓦斯运移的影响,开展了一系列工作:(1)充填开采技术理论分析。充填方法、充填比、充填开采的理论分析。(2)采空区瓦斯运移分布规律理论研究。瓦斯在煤层中流动的基本参数、赋存和运移、瓦斯运移分布规律的理论分析。(3)充填采空区物理及多孔介质渗流力学模型的建立分析。构建了充填采空区三维物理模型,对多孔介质中传质过程分析,得出采空区瓦斯运移的控制方程,并建立了充填采空区瓦斯运移数学模型。(4)利用Gambit建立U型和Y型两种通风系统模型,导入到FLUENT计算流体力学软件对充填煤矸石、灰渣和泥沙三种充填物的采空区瓦斯运移情况进行数值模拟;模拟按孔隙率的分布不同分为两大部分进行,即把整个采空区分为孔隙率均匀分布和孔隙率非均匀分布两种情形,其中在Y型通风系统下模拟了有瓦斯抽放时的采空区瓦斯运移情况。在进行了一系列的理论分析和数值模拟后,得出了以下主要结论:(1)煤矸石、灰渣、泥沙三种充填物对采空区瓦斯运移有一定的影响,不同的充填物对瓦斯运移的影响差别很大。(2)煤矸石粒径大,抗压强度大,受压后空隙率变化小,充填煤矸石有利于减少采空区中深部的瓦斯积聚,而充填灰渣和泥沙时效果不如煤矸石。(3) U型通风系统下,三种充填物的采空区回风巷一侧和上隅角都有不同程度的瓦斯积聚,Y型通风系统较好解决了这些问题。(4) Y型通风系统在有抽放的条件下能很好的解决充填采空区回风巷一侧和上隅角的瓦斯积聚问题。更多还原

【Abstract】 Recently, environment and energy issues become more and more prominent, coal mining tends to be non-pollution, so that, green technique is proposed in coal mining. Conventional mining technique causes to serious subsidence, huge gangue volume and serious pollution. If rainwater permeated into self-igniting gangues, the heated air will rapidly expand,which will result in explosion,and cause greater damage. Thus,coal gangue must be comprehensively controlled. To realize backfill mining,through filling waste material like coal gangue,clinker and etc into coal mine, is the effective way to solve subsidence, and treat varieties of waste material. In addition,the volume of coal under three circumstances(three under)is rather huge, with gradually depleting coal resource,the problem of unexploited coal of three under will be confronted with in lots of mine areas,and backfilling mining is used to solve this.However,at present,gas migration of goaf under filling condition comes.At home and abroad,there are many research findings on gas migration,but fewer researches on gas migration under filling condition.Nowadays,it is of great significances to research gas migration under filling condition in coal goaf.In this thesis,focusing on gas migration regulation under filling condition,by aid of rock mechanics,fluid mechanics,gas seepage theory,porous media seepage theory and corresponding theories,by applying theoretic analysis,physical mathematic modeling analysis,computer simulation and etc,in coal mine,equipped with U shaped and Y shaped ventilation system,influence of backfilled coal gangue,clinker and sediment on gas migration is researched.Research tasks are as follows:(1)Theoretic analysis on backfilling mining technique,backfilling methods, backfilling ratio are carried out.(2)Theoretic researches on distribution regulation of gas migration in goaf.Basic parameters,storage and migration,distribution regulation of gas migration are theoretically researched,when gas flows in coal seams.(3)Establishment of physical model of backfilled goaf and seepage mechanic model of porous medium.3-dimentioned physical model of backfilled goaf is constructed; mass transfer process of porous medium is analyzed,controlling equation of goaf gas migration is obtained,and mathematical model of gas migration is established.(4)Models of U-shaped and Y-shaped ventilation system are constructed with Gambit,which are brought into FLUENT software to numerically simulate the gas migration situation in goaf that filled with coal gangue,clinker and sediment.The simulation is divided into two parts according to distribution of porosity,it means the whole goaf is divided into homogeneous distribution of porosity and heterogeneous distribution of porosity.In Y-shaped system,gas migration situation is simulated under drainage condition.When theoretic analysis and numerical simulation have been finished,the conclusions are as follows:(1)Influence of coal gangue,clinker and sediment on gas migration is obviously different.(2)As to coal gangue,diameter is big,compressive strength is large,porosity changes less,backfilled coal gangue contributes to decrease gas accumulation in deep goaf,its effect is better than filling clinker and sediment.(3)In U-shaped ventilation system,in goaf with three fillings,there is gas accumulation of varying degree in return airway and upper corner;Y-shaped ventilation system can solve the problem better.(4)Under drainage condition,gas accumulation can be worked out with Y-shaped ventilation system.更多还原