连续采煤机块段式开采覆岩关键层破断规律与控制研究

发布时间：2018-03-10 23:52

本文选题：连续采煤机　切入点：块段式开采　出处：《中国矿业大学》2015年硕士论文　论文类型：学位论文

【摘要】：基于色连煤矿1号矿井2-2上煤层边角煤回收的工程背景,综合运用了现场采样测试,理论计算与分析,数值模拟与分析,现场工业试验等研究方法,对连续采煤机块段式开采残留煤柱稳定性、覆岩运移及关键层破断规律、顶板控制技术进行了系统的研究,主要研究成果如下:(1)运用突变理论方法,建立了区段隔离煤柱的力学模型,并推导出其发生突变失稳的力学条件为:煤柱的弹性核区宽度占其总宽度的百分比低于14%时,外界若有轻微扰动,煤柱将发生突变型失稳破坏;反之,煤柱发生的是逐步破坏,积聚的能量缓慢释放。运用数值模拟和现场试验的方法对结果进行了验证,结论与理论计算基本相符,揭示了区段隔离煤柱失稳机理研究的合理性。(2)根据色连一号矿井2-2上煤层开采的地质条件,结合岩层柱状图及关键层判别软件得出了2-2上煤层属于多层关键层顶板结构,据此建立了多层关键层破断的力学模型,运用弹性薄板理论对关键层的初次断裂及周期断裂步距进行了理论计算,并针对特定情况对理论计算值进行了修正,为块段式开采顶板岩层控制提供了理论依据。(3)运用FLAC3D数值模拟软件对2-2上煤层块段式开采过程进行计算建模,通过监测模型开采过程中煤柱及关键层的应力、位移和塑形区变化来分析了保护煤柱稳定性与关键层破断的相关性、上覆岩层的运移及关键层的破断规律。得到煤柱及关键层的变形破坏之间存在一定相关性,二者可视为一个“煤柱—亚关键层—主关键层”的系统;亚关键层随着工作面的推进,发生弯曲下沉,在岩板中部下边缘首先出现拉破坏区,随后岩板周围出现剪切破坏,中部拉破坏区最终贯穿岩板,亚关键层在推进到20m左右发生初次破断,推进到26m左右发生第一次周期破断,此后大约7m左右有一次周期破断;主关键层的破坏主要为剪切破坏,在亚关键层发生第3次周期破断之前,主关键层发生初次破断,引起上覆岩层及保护煤柱发生较大的变形和破坏。(4)分析了留设保护煤柱及注浆充填技术在块段式开采顶板控制中所起的作用,通过数值模拟对注浆充填技术的机理和效果进行了分析研究。得到适合该现场情况的区段隔离煤柱合理宽度为12~15m;注浆充填技术一方面可以对区段隔离煤柱形成保护,降低其屈服区的发育程度,从而可以在开采过程中充分发挥其对上覆岩层的支撑作用;另外一方面,可以有效控制上覆岩层,尤其是主、亚关键层的弯曲下沉,同时也对开采前方待采煤房的偏帮起到一定抑制作用。
[Abstract]:Based on the engineering background of coal recovery from 2-2 upper coal seam in No. 1 coal mine of Xilian Coal Mine, the research methods such as field sampling test, theoretical calculation and analysis, numerical simulation and analysis, field industrial test and so on are used synthetically. The stability of residual coal pillar in block mining of continuous shearer, the law of overburden migration and breaking of key strata, and the roof control technology are systematically studied. The main research results are as follows: 1) catastrophe theory method is used. The mechanical model of section isolation pillar is established, and the mechanical condition of sudden instability is deduced: when the width of elastic core area of coal pillar is less than 14% of its total width, if the outside world has slight disturbance, On the contrary, the coal pillar will be destroyed step by step and the accumulated energy will be released slowly. The results are verified by numerical simulation and field test, and the results are in good agreement with the theoretical calculation. This paper reveals the rationality of the study on the mechanism of instability of coal pillar in section isolation. According to the geological conditions of mining upper coal seam 2-2 in Xilian No. 1 mine, combined with the columnar map of rock layer and the critical layer discrimination software, it is concluded that the upper coal seam of 2-2 belongs to the roof structure of multi-layer key layer. Based on this, the mechanical model of multi-layer critical layer fracture is established, and the theoretical calculation of the initial and periodic fracture step of the critical layer is carried out by using the elastic thin plate theory, and the theoretical calculation value is modified according to the specific situation. This paper provides a theoretical basis for roof strata control in block mining. It uses FLAC3D numerical simulation software to calculate and model the block mining process of 2-2 upper coal seam, and monitors the stress of coal pillar and key strata in the process of model mining. The correlation between the stability of the protection coal pillar and the breakage of the key strata, the migration of the overlying strata and the breaking rule of the critical layer are analyzed by the displacement and the change of the shape area. The correlation between the deformation and failure of the coal pillar and the key layer is obtained. They can be regarded as a system of "coal pillar, sub-critical layer and main critical layer". The sub-critical layer bends and sinks with the advance of the working face, and the tensile failure zone first appears in the bottom edge of the rock slab, and then the shear failure occurs around the rock slab. The central tensile failure zone finally runs through the rock slab, and the subcritical layer breaks for the first time at about 20m, the first periodic fracture occurs at 26m or so, and then there is a periodic fracture about 7m after that, and the main failure of the key layer is mainly shearing failure. Before the third cycle break occurs in the sub-critical layer, the main critical layer breaks for the first time. Causes large deformation and destruction of overlying strata and protection pillars. The paper analyzes the role of retaining and protecting coal pillars and grouting filling technology in the control of block mining roof. Through numerical simulation, the mechanism and effect of grouting filling technology are analyzed and studied. The reasonable width of section isolation pillar is 12 ~ 15m, which is suitable for the field conditions. On the one hand, grouting filling technology can protect the section isolation pillar. In order to reduce the development of the yield zone, it can give full play to its supporting role to the overlying strata during the mining process. On the other hand, it can effectively control the bending and sinking of the overlying strata, especially the main and subcritical strata. At the same time, it also plays a certain role in restraining the side of the coal house in front of mining.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD325

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