【作者】 聂明军；

【导师】 杨为民； 吴文金；

【作者基本信息】 安徽理工大学 ， 地质工程， 2008， 硕士

【摘要】 煤层顶板稳定性是影响煤矿安全生产、顶板支护管理的重要因素之一。木城涧矿随着煤层开采深度的不断增加,煤层顶板稳定性问题日趋突出,已严重影响回采生产工作,该矿过去对煤层顶板稳定性问题尚未开展系统研究。因而,开展主采煤层顶板工程地质特性和稳定性研究对指导该矿安全高效生产有重要意义。本文以木城涧矿侏罗系主采煤层二煤、十煤为研究对象,运用构造地质、岩石力学和工程地质等学科理论和方法,从顶板的沉积相、岩性、岩性组合和构造等方面入手系统研究了主采煤层的工程地质特性,分析了影响煤层顶板稳定性的因素,提出二煤、十煤顶板的工程地质分类,并对其稳定性进行综合评价和分区,在此基础上采用FLAC^2D软件模拟探讨了不同煤层顶板岩体结构模型的采动效应。取得以下主要认识:（1）该矿侏罗系煤系地层系三角洲相沉积,二煤、十煤顶板伪顶岩性为砂质泥岩,直接顶岩性为粉砂岩、细砂岩,老顶岩性为中细砂岩;岩性组合以粉砂—细砂岩组合为主。（2）该矿主体构造为庙安岭—髫髻山向斜的南东翼,受多期构造活动的影响,矿区构造以褶皱为主、断裂为辅,小褶皱表现为一系列次级背向斜,小褶皱的形态在南部及北部比较开阔舒缓,中部比较紧闭,致使煤层顶板产状变化大,顶板破碎,完整性较差。在构造发育地区,煤层顶板稳定性差。（3）顶板岩石力学测试结果表明:岩块单轴抗压强度大,粉砂岩达141.6MPa,砂质泥岩达165.4MPa,细砂岩达213.5MPa,均属硬质岩石,顶板稳定性好;但受构造影响,顶板岩体裂隙较发育,顶板破碎,稳定性变差。（4）二煤、十煤顶板工程地质分类结果表明:二煤、十煤顶板以二类周期来压和三类周期来压强烈顶板为主。周期来压平均步距在18.5～22.3m,周期来压对煤层顶板稳定性和支架稳定性有重要影响。（5）依据顶板岩体岩性—结构分类,二煤、十煤顶板稳定性可分为极不稳定顶板、不稳定顶板、稳定顶板和非常稳定顶板四种类型。以稳定和非常稳定顶板为主,二煤极不稳定和不稳定顶板主要分布在研究区东部,约占整个面积的35%;十煤极不稳定和不稳定顶板主要分布在研究区中部,约占整个面积的20%。整体二煤顶板稳定性比十煤顶板稳定性较差。（6）根据煤层顶板沉积和构造特征,建立煤层顶板岩性的完整层状模型（上软下硬、上硬下软、全硬和全软）、断层构造模型和褶曲构造模型,应用FLAC^2D软件模拟了在采动影响下不同顶板岩体破坏的基本特征。模拟结果表明:①在采动影响下,煤层顶板的破坏特征与顶板的岩性、厚度、组合、工作面的斜长和煤层倾角等因素有关。②断层模型中,在断层附近应力集中明显,当工作面推过断层带时,顶板冒裂带发育增大,顶板稳定性差。③褶曲模型中,向斜煤层顶板冒裂高度比背斜大,顶板稳定性相对较差。④实际工作面模拟结果表明:顶板冒裂高度分别为16.8m、33.5m,工作面前方10.8～20.75m范围内为采动影响区,最大垂直应力集中系数达到4.2。模拟结果与实际情况较吻合。影响煤层顶板稳定性的因素很多,有待结合地质和工程因素（支架类型、回采速度等）综合评价顶板—支护—底板系统稳定性。更多还原

【Abstract】 Seam top’s stability is one of the most important factors that influence coal mine’s production and propping of top.With the increasing of coal seam’s depth in Muchengjian coal mine,seam top’s stability problem is more and more prominent so that it influences stope seriously.The coal mine has not studied seam top’s stability in the past.so the study of seam top’s engineering geological condition and its stability were carried out,its significance in the coal mine’s production is very important.The paper’s object is No.2 and No.10 seam of Jurassic system in Muchengjian coal mine,Some discipline’s theory such as structural geology and rock mechanics and engineering geology were used.The study of seam top’s engineering geological condition and factors influence seam top’s stability were systemly carried out in seam top’s sedimentary facies and lithology and lithology’s combination and structure,the engineering geological styles were obtained,the seam top’s stability and stability’s distribution were also obtained,besed on all the analysis above,we discuss the mining effect of different rockmass’s structure by FLAC^2D software.the main conclusions are as follows:（1） Jurassic coal measures strata is delta facies,the false roof’s lithology is sandy mudstone,the ditect roof’s lithology is siltstone and sandstone;the old roof’s lithology is fine sandstone,Lithology’s assioation mainly is siltstone-fine sandstone,seam roof’s stability is well.（2） The main tectonic is miaoanling-zhaojishan syncline,as the result of multicycle structure,the main structure is fold and the secondary structure is faults,for these reasons,seam’s occurrence is seriously transformed,seam top is very crushing and it is not intact.The seam top’s stability is very bad in the situ where structure is well-developed.（3） Test result of rock’s mechanics shows:the single pressure stronginess of the rock is large,siltstone’s stronginess is 141.6MPa,sandy mudstone’s stronginess is 165.4MPa,fine sandstone’s stronginess is 213.5MPa,all these rock are hard and stable;but as the result of structures,seam top is very crushing,so its stability is become bad. （4） The result of seam top’s engineering geological styles shows:the seam top’s has the periodic weighting.The step distance of the periodic weighting is 15.5～22.3 meters,the periodic weighting has important influence on the stability of seam top and support.（5） Based on roof’s rockmass lithological character-textural classification,the roof’s stability styles can divide into four kind of types that is extremely unstable roof, unstable roof,stable roof and extremely stable roof.Stable and extremely stable roof is primarily,No.2 coal’s extremely unstable and unstable roof mainly distributes east of the research area,composed 35%of entire area;No.10 coal’s extremely unstable and unstable roof mainly distributes middle of the research area,composed 20%of entire area.No.2 coal’s roof is less stable compared to No.10 coal’s roof.（6） According to the characteristics of seam top’s deposition and structure,seam top’s lithological integrity layered model and fault model and fold model were establishment,and simulated the basic destroyed characteristics of different roof’s rockmass which under mining effect by using the FLAC^2D software.The simulated results shows:①Under mining effect,the basic destroyed characteristic of roof’s rockmass is related to roof’s lithology and thickness and lithological assioation and working face’s length and seam’s inclination angle.②In the fault model,the stress concentration is obvious nearby the fault,When the working face has pushed the fault zone,the roof caving and crack’s growth altitude to be increase,the roof’s stability is bad.③In the fold model,the roof caving and crack’s altitude of syncline is bigger than anticline’s,and its stability is badder.④The simulated results of actual working face shows:the roof caving and crack’s altitude respectively is 16.8m,33.5m,front the working surface in the 10.8～20.75m is mining effected scope,the most greatly vertical stress’s concentration coefficient achieves 4.2.The simulated result is consistent with the actual situation.The factors influence seam top’s stability are very many,it is necessiary to unify both the geologic and the engineering factors to evaluate roof-support-floor system’s stability.更多还原