【作者】 刘德乾；

【导师】 姜振泉；

【作者基本信息】 中国矿业大学 ， 地质工程， 2009， 博士

【摘要】 矿井冲击地压引发的动力灾害是矿井最严重的自然灾害之一,其形成受厚层坚硬顶板条件、坚硬而脆性的煤层条件、高自重应力或构造应力和因煤层采动造成的应力集中带的影响,在深井开采条件下尤为突出。论文以岩体工程地质力学和矿山压力理论为指导,结合菏泽煤田赵楼矿井实际地质条件,系统进行了煤岩力学性质及冲击倾向性试验研究和构造条件分析,建立了首采区工作面不同顶板条件的工程地质模型和力学模型,在此基础上重点就煤层开采顶板及煤柱受力、变形特征问题进行了离心模型试验、力学解析和数值模拟分析,以为后期安全生产提供科学依据。论文主要取得以下研究成果:根据区域构造资料,结合赵楼井田物探资料,分析赵楼井田构造作用特点,了解井田构造演化规律,系统研究井田构造分布、组合规律,分析不同级别、不同序次、不同性质构造的相互制约和分布特征,把握井田主要构造及其构成的网络。经过赵楼矿井煤岩体取样、煤岩体力学性质测试,反映出3煤直接顶板中细砂岩强度高,其弹性变形和脆性破坏特征非常明显;经过对煤样的冲击能量指数、弹性能量指数和动态破坏时间指标的测试,3煤具有强冲击倾向性,经过对3煤顶板砂岩弯曲能量指数的计算,顶板具有弱冲击倾向性,具备了矿井冲击地压的必要条件。进行了离心模型试验,利用三组模型分别研究完整连续顶板情况、工作面推进方向与结构面倾向一致和相反的情况下,由于煤岩层的采动对开切眼处煤柱、工作面前方煤体、直接顶和老顶岩层应力变化和变形情况。顶板被断层切割情况下,顶板岩层的完整性受到破坏,应力在构造部位重新分布,形成构造应力的集中,是引发冲击地压的危险部位,但采掘工艺也会导致顶板和煤柱受力与变形的差异。建立了首采区工作面揭露断层前后的力学模型,进行了解析:工作面揭露断层前后,顶板岩层最大剪应力和最大弯矩发生在固定端发生在固定端,但其大小均发生了变化,临近断层时,工作面直到断层处的煤层,随工作面向断层推进,煤层的支承压力升高,为煤的抗压强度控制,易发生片帮。利用FLAC2D软件,进行了数值模拟分析,获得了不同顶板结构条件模型采动过程中煤柱、直接顶板和老顶的应力分布及变形特征的综合对比结果,模拟反映出了采动过程煤柱及顶板聚压情况及断层结构对其产生的影响特点。无论是逆断层倾向开采,还是顺断层倾向开采,由于断层结构面的存在,使顶板稳定性较差,逆断层倾向开采条件下,临近断层处虽易形成结构,但易因顶板动态变化,开采及支护条件而破坏,顺断层倾向开采,由于结构面的弱化,易沿结构面发生岩层移动,引发断层“活化”,使矿压显现和岩层冒落严重。更多还原

【Abstract】 As one of the most dangerous mining the geologic hazards,the rock burst, occurs with high frequency.The problems of rock mechanics caused by the deep mining engineering are the focuses in the fields of mining engineering and rock mechanics.The rock burst is influenced by many factors, mainly is the condition of thick and stiff Peak, the condition of stiffness and brittleness of coal, the condition of high ground stress and the stress concentrate areas because of Excavation. In order to make the design and layout of the coalmine reasonable, the paper, based on the concretely geological condition of deep buried coal in Zhaolou coalmine, combined the structure and geophysical information, a test of mechanics character of rock and coal is carried, centrifugal model experiment is carried, geological and mechanical model is set up and is analyzed, a numerical simulation analysis is completed. The main conclusion of the paper is follow:Based on the region structure and geophysical information of Zhaolou coalmine, the structure characteristic is analyzed, the law of structure evolvement is explained, the law of distributing and combination of the structure is systemic studied, the main structure and it’s constitutive net is obtained.This paper started with the experiment of coal burst tendency that was conducted in main mining coal seam.Through the experiment and analysis of the impact energy index,elastic energy index,dynamic destruction time of coal sample,and the Bending energy index of rock sample,the rock burst tendency of the coal is high and the tendency of rock is weakA centrifugal model simulation is processed in order to study the law of deformation and stress distributing because of different roof conditions. As a result of coal mining, coal pillar at the places of first cut, coal in front of workface, direct roof strata and basic roof strata, the rock stress and deformation is different. Three sets of models are built ,they are the conditions of the integrity of the roof , the excavation direction athwart the tendency of the structure ,just as the condition of normal fault and the excavation direction toward the tendency of the structure ,just as the condition of reverse fault .Because of the damage of the integrity of rock roof, the stress redistribution in the structural parts to form a concentration of tectonic stress, it is triggered shocks to the risk of pressure parts, but the extraction process can also lead to structural differences in the impact.According to the geology model when workface encounters fault, two mechanics model are built, one is the workface uncovers fault, another is workface just crosses fault, they are different, because of restriction condition, the coal roof mechanics behaviors are different when workface before and after the fault. The most shear strength and moment are happened at different place, when workface is nearer to fault, coal bed between the workface and fault just like coal pole, the bearing pressure rises with the workface advances, coal side is easy to crush, it is controlled by the coal intensity of pressure.FLAC2D software is used to carry out a numerical simulation analysis, to obtain a different model of the structure of the roof conditions in the process of mining, coal pillars, direct roof and basic roof the stress distribution and deformation characteristics of a comprehensive comparison of the results of simulation reflects the process of mining coal pillars and Poly roof pressure and fault structure of the impact of their characteristics. Mining the course of a complete roof structure and deformation of the basic state symmetry, and the fault cutting roof stress distribution and deformation of migration occurred in the fault surface structure of discontinuous parts of the deformation and stress distribution of concentration is very obvious.更多还原