浅埋煤层采场覆岩破坏及地表移动规律研究.pdf

万方数据 Research on the Law of Overburden Failure and Surface Movement in Shallow Seam Dissertation ted to Xi’an University of Science and Technology In Partial Fulfillment of the Requirement For the Degree of Doctor of Engineering By Li Jinhua School of Architecture and Civil Engineering Dissertation Directed by Professor Gu Shuancheng June，，2017 万方数据 万方数据 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； 论文题目 浅埋煤层采场覆岩破坏及地表移动规律研究 学科名称 岩土工程 博 士 生 李金华 （签名） 指导老师 谷拴成 （签名） 万方数据 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。 关 键 词 浅埋煤层；覆岩破坏；地表移动；薄板理论；末采阶段 研究类型 应用研究 万方数据 Subject Research on the law of overburden failure and surface movement in shallow seam Specialty Geotechnical Engineering Name Li Jinhua （Signature） Instructor Gu Shuancheng （Signature） ABSTRACT Shenfu-Dongsheng coal field, as the seventh largest coal field in the world, accounts for about 1/3 of coal reserves in China. It will lay the good foundation for the national energy to the strategy of“the Belt and Road Initiatives”，with the construction and development of it. It shows that roof disaster is very serious, as a typical shallow seam in the area, which due to the severe pressure under the stoping process. Meanwhile, strata and surface movement caused by mining, which leads to surface subsidence so that it exacerbates the surface soil erosion and desertification. Therefore, it is an important subject that urgent needs to be solved, which is about to study on failure mechanism of overlying strata structures in shallow seam, and to establish a reasonable surface subsidence model and prediction theory of shallow seam mining area. In this paper, in order to study on the failure of the overlying strata structures in shallow seam and the laws of surface movement, taking the strata movement and surface subsidence which causes by mining face in Shenfu-Dongsheng coal field as an object, and using the s of field observation, theoretical analysis, mathematical modeling, measurement and verification. The main research contents and conclusions are as follows （1） Based on the theory of elastic thin plate, according to the boundary conditions about the initial pressure and periodic weighting of the stope, the mechanical model of roof under different boundary conditions was established. The deation and mechanical characteristics of the old roof before and after the roof fracture were analyzed. The prediction ula of step distance about the initial pressure and periodic weighting was given, and the influence factors of the initial pressure step distance of the roof was analysed. According to the measured data of different working face mine pressure, the theoretical calculation value and the measured value were compared and analyzed, and the reliability and applicability of the model were verified. 万方数据 2 According to the characteristics about the influence of the abutment pressure in the later stage of the working face on stress distribution of surrounding rock of withdrawal channel, the concept of the final mining stage was defined; Based on the deation mechanism of the old roof and direct roof, the mechanical analysis model of the direct roof in the final mining stage was established, and the ula for calculating the roof pressure in the final mining stage was given; The relationship between the step distance of periodic weighting on the old roof and the direct roof parameter in the final mining stage was analyzed. 3 Based on the monitoring of the mine pressure of the 15201 working face in Zhang Jia Mao coal mine, the dynamic process and distribution characteristics of the initial support force and the final resistance of the working face during mining were analyzed, and the supporting characteristics of the stope support were also analyzed and uated. And the basic law of mine pressure behavior in shallow coal seam was also mastered. 4 According to the surface subsidence model of three-dimensional elastic thin plate, the prediction ula of surface movement caused by underground excavation was deduced; The dynamic surface subsidence prediction model based on Schnute time function was established; The characteristics and laws of surface subsidence at different speeds and times were analyzed. 5 According to the dynamic distribution characteristics of the advance support pressure in the final mining stage, the influence process of the advance support pressure on the withdrawal channel was analyzed. The initial distance of withdrawal channel in the impact of the dynamic mining effect was determined. The influence range of final mining stage was given quantitatively; According to the characteristics of the mining pressure in the final mining stage, the pressure control measures were put forward. Key words Shallow seam；Overburden failure；Surface Movement；Thin plate theory；Final mining stage Thesis Application Research 万方数据 目 录 I 目目 录录 1 绪论 1 1.1 选题背景及研究意义 1 1.2 国内外研究现状 2 1.2.1 矿压假说的国内外研究现状 2 1.2.2 采场顶板来压步距研究现状 5 1.2.3 采场顶板来压步距影响因素研究现状 8 1.2.4 末采阶段来压研究现状 9 1.2.5 地表沉陷预测研究现状 10 1.3 研究思路、研究内容和技术路线 13 1.3.1 研究思路 13 1.3.2 研究内容 13 1.3.3 技术路线 14 2 基于薄板理论的采场顶板断裂模型研究 15 2.1 弹性薄板的基本理论 15 2.2 采场老顶初次来压步距计算分析 19 2.2.1 计算力学模型 19 2.2.2 初次来压挠曲变形方程 20 2.2.3 初次来压阶段应力分析 23 2.2.4 初次来压步距计算 27 2.3 采场老顶周期来压步距计算分析 29 2.3.1 计算力学模型 29 2.3.2 周期来压挠曲变形方程 30 2.3.3 周期来压阶段应力分析 31 2.3.4 周期来压步距计算 33 2.4 采场老顶来压步距影响因素分析 33 2.4.1 工作面倾向长度的影响分析 34 2.4.2 老顶岩层厚度 35 2.4.3 老顶上覆岩层厚度 36 2.4.4 老顶岩层抗拉强度 37 2.5 本章小结 37 万方数据 目 录 II 3 末采阶段矿压规律及回撤通道稳定性研究 39 3.1 末采阶段定义 39 3.2 基于直接顶老顶协调变形的末采阶段来压步距分析 41 3.2.1 采场老顶末采阶段力学模型 41 3.2.2 力学模型分析 41 3.3 直接顶对周期来压步距的影响分析 44 3.3.1 直接顶厚度 44 3.3.2 直接顶弹性模量 45 3.3.3 直接顶内摩擦角 46 3.4 算例分析 47 3.4.1 工程概况 47 3.4.2 监测方案 48 3.4.3 数据分析 49 3.5 末采阶段回撤通道稳定性分析 53 3.6 末采阶段起始距离确定 54 3.6.1 末采阶段工作面超前支承压力分布 54 3.6.2 回撤通道受动采影响起始距离确定 60 3.7 末采阶段顶板合理断裂位置确定 61 3.8 本章小结 62 4 综采工作面矿山压力现场监测 63 4.1 张家峁煤矿 15201 工作面矿压监测 63 4.1.1 工作面基本情况 63 4.1.2 矿压监测方案 64 4.1.3 走向矿压显现规律 64 4.1.4 倾向矿压显现规律 73 4.1.5 工作面支架支护特性分析 76 4.2 实测来压步距与理论对比分析