浅埋煤层采场覆岩破坏及地表移动规律研究

发布时间：2018-10-17 22:01

【摘要】：神府-东胜煤田作为世界第七大煤田,其储量约占全国探明储量的三分之一,它的建设开发将为国家“一带一路”战略奠定良好的能源基础。大量开采实践表明,作为典型的浅埋煤层赋存地区,回采过程中由于矿压显现剧烈,顶板灾害时有发生;同时开采引起岩层和地表移动,造成地表塌陷,加剧了地表水土流失和荒漠化。鉴此,开展浅埋煤层采场覆岩结构破坏机理的研究,建立合理的浅埋煤层矿区地表沉陷模型和预测理论,是目前亟待解决的重要课题。本文以神府-东胜煤田南部矿区回采工作面引起的岩层移动和地表沉陷为主要研究对象,采用现场观测、理论分析、数学建模、实测验证等方法,对浅埋煤层采场覆岩破坏及地表移动规律进行了研究,主要研究内容和结论如下:(1)基于弹性薄板理论,根据采场初次来压和周期来压边界条件,建立了不同边界条件下顶板力学模型;分析了顶板断裂前后采场老顶变形和力学特征,提出了采场老顶初次来压和周期来压步距预测公式,对影响采场顶板初次来压步距的因素进行了参数分析。根据不同工作面矿山压力实测数据,对理论计算值和现场实测值的对比分析,验证了模型的可靠性和适用性;(2)根据工作面回采后期超前支承压力对回撤通道围岩应力分布影响特征,对末采阶段概念进行了定义;基于老顶、直接顶协调变形机理,建立了末采阶段直接顶力学模型,给出了末采阶段采场顶板来压计算公式;分析了末采阶段老顶周期来压步距与直接顶参数之间的函数关系;(3)根据末采阶段采场超前支承压力动态分布特征,分析了回撤通道受工作面超前支承压力的影响过程,确定了回撤通道受动采影响的起始距离,定量给出了末采阶段范围;(4)通过张家峁煤矿15201工作面矿压监测,分析了工作面回采过程中支架初撑力、末阻力的动态变化过程和分布特征,对采场支架支护特性进行了分析评价,得到了浅埋煤层采场矿压显现的基本规律;(5)根据三维弹性薄板地表沉降模型,推导了地下开挖引起的地表移动预测公式;基于Schnute时间函数建立了动态地表沉陷预测模型;分析了不同速度、不同时间下地表下沉的特征和规律。
[Abstract]:As the seventh largest coalfield in the world, Shenfu-Dongsheng coalfield occupies about 1/3 of the proven reserves in China. Its construction and development will lay a good energy base for the country's "Belt and Road" strategy. A large number of mining practices show that, as a typical area where shallow coal seams occur, roof disasters occur from time to time due to severe mine pressure in the process of mining, and at the same time, mining causes rock strata and surface movement, resulting in surface collapse. It exacerbates soil erosion and desertification on the surface of the earth. In view of this, it is an important task to study the failure mechanism of overburden rock structure in shallow coal seam stope and to establish a reasonable subsidence model and prediction theory in shallow coal seam mining area. In this paper, the strata movement and surface subsidence caused by the mining face in the southern mining area of Shenfu-Dongsheng coalfield are taken as the main research objects, and the methods of field observation, theoretical analysis, mathematical modeling and verification are adopted in this paper. The rules of overburden rock failure and surface movement in shallow coal seam are studied. The main contents and conclusions are as follows: (1) based on the elastic thin plate theory, according to the boundary conditions of initial pressure and periodic pressure in the stope, The mechanical model of roof under different boundary conditions is established, the deformation and mechanical characteristics of the main roof before and after roof fracture are analyzed, and the prediction formulas of the first pressure and periodic step distance of the main roof are put forward. The parameter analysis of the factors affecting the first step distance of stope roof is carried out. According to the measured data of mine pressure in different working faces, the theoretical calculation value and the field measured value are compared and analyzed. The reliability and applicability of the model are verified. (2) according to the characteristics of the influence of the leading support pressure on the stress distribution of the surrounding rock of the withdrawal passage in the late mining stage of the working face, the concept of the stage of final mining is defined; based on the mechanism of coordinated deformation of the main roof and the direct roof, The direct roof mechanics model of the end mining stage is established, and the formula for calculating the roof pressure in the end mining stage is given. This paper analyzes the functional relationship between the step distance of the main roof period and the direct roof parameters in the stage of the end mining. (3) according to the dynamic distribution characteristics of the leading supporting pressure of the stope in the stage of the end mining, the influence process of the withdrawal passage by the leading supporting pressure of the working face is analyzed. The starting distance of the withdrawal passage affected by dynamic mining is determined, and the range of final mining stage is quantitatively given. (4) through the monitoring of mine pressure in 15201 face of Zhangjiaomao Coal Mine, the initial supporting force of support in the process of mining is analyzed. Based on the dynamic change process and distribution characteristics of final resistance, the characteristics of support in stope are analyzed and evaluated, and the basic rules of mine pressure in shallow coal seam are obtained. (5) according to the surface subsidence model of three dimensional elastic thin plate, The prediction formula of surface movement caused by underground excavation is derived, the dynamic surface subsidence prediction model is established based on Schnute time function, and the characteristics and laws of surface subsidence under different speeds and times are analyzed.
【学位授予单位】：西安科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD325

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