本文以霍州煤电集团有限责任公司李雅庄煤矿为研究对象，针对其 2 号煤层 存在的高瓦斯、高应力条件，采用理论分析、现场测定、实验室测试和数值模拟 等方法，开展了下保护层开采卸压保护范围及可行性研究工作。保护层开采就是 通过对保护层的开采使被保护层卸压，释放煤层的弹性潜能，增大煤层的透气性， 从而有利于被保护层瓦斯流动、解吸和含量减少，达到降低煤层瓦斯内能的目的。 为了分析下保护层开采的卸压保护范围，并确定其可行性，研究了下保护层开采 过程中被保护层应力和变形分布规律，被保护煤层的应力分布沿走向方向从开切 眼到停采线依次经历应力集中区、应力卸压区和应力集中区等三个阶段，沿倾斜 方向从上巷到下巷也依次经历上述三个阶段，但较前者分布不够均匀；被保护煤 层变形沿走向和倾向均呈现压缩、膨胀、压缩的变化规律，最大膨胀变形出现在 采空区中上部；确定了下保护层开采后被保护层走向、倾向保护范围；研究了 6 号煤层作为下保护层开采时底板承压水的运移规律，在防水煤柱留设宽度分别为 20m、40m、60m、80m、100m、120m、140m、160m 时，均有可能在工作面切眼、 停采线处煤壁以及底板岩层等部位发生突水；利用有效隔水层突水系数法对 6 号 煤层作为下保护层开采时的底板突水危险性进行了评价，6 号煤层底板标高小于 289.28m 的区域为 K 2 太灰水突水危险区，6 号煤层底板标高大于 289.28m 的区域 为 K 2 太灰水突水威胁区，6 号煤层可采范围内为奥灰水突水威胁区；从防治水的 角度确定了下保护层开采的可行性，李雅庄煤矿 6 号煤层作为下保护层开采不可 行，但为了保证能源的充分利用，可以利用底板注浆加固进行带压开采。 关键词，下保护层；应力；变形；保护范围；突水；数值模拟III Abstract Taking Liyazhuang coal mine of Huozhou coal electricity group Co.,LTD as the research object,according to its high gas and stress conditions in No.2 coal seam,using theoretical analysis,field measurement,laboratory test and numerical simulation method, this thesis carries out the study on pressure-relief protective area and the feasibility of lower protective coal seam mining.The theory of protective seam exploitation is that it can release the gas pressure and elastic potential energy of protected coal seam,and increase the protected seam’s permeability.Gas flow in the protected seam becomes easier.With gas desorption increasing and gas content decreasing,gas internal energy in seam is dropped.In order to analyze pressure-relief protective area and to determine the feasibility with the exploitation of lower protective seam,this thesis researches on the distribution regulation of strain and stress in the overlaying protected coal seam during the lower protective seam exploitation.Three stress distribution areas from open-off cut to stop line along strike are:concentrated area,released area and concentrated area.Along dip,the distribution also obeys this regulation from upper roadway to lower roadway,but the latter isn’t more uniform.The strain distribution regulation is compression,expansion and compression along both strike and dip.The max expansion occurs at the upper district of the goaf roof. This thesis identifies that the protective area along both strike and dip. It also researches on the moving regulation of pressurized water in No.6 coal seam during the exploitation of lower protective seam, and finds that water inrush occurs at open-off cut,stop line, rocky bottom when the width of waterproof coal pillar is respectively set at 20m、40m、60m、80m、100m、120m、140m、160m. Then it evaluates water inrush hazard in coal floor by water inrush coefficient method of effective water-resisting strata.The area under the level of 289.28 m in No.6 seam is water inrush risky zone of K 2 limestone water in Taiyuan group, and the area above it is threatened zone. The whole exploitable area of the coal mine is water inrush threatened zone of Ordovician limestone water.Finally, it identifies that the exploitation of lower protective coal seam is infeasibility from the aspect of preventing and curing water disaster.But in order to ensure the sufficient use of energy, the coal seam can be exploited under pressure by floor grouting-strengthening.IV Keywords: Lower protective seam；Stress；Deformation；Protective area；Water inrush；Numerical simulationV 目 录 摘要 I 目 录 V 1 绪论 1 1.1 研究背景与研究意义................................................................................................ 1 1.2 国内外研究现状及存在问题.................................................................................... 2 1.2.1 保护层开采研究现状 ................................................................................................................ 2 1.2.2 底板突水机理研究现状 ............................................................................................................ 3 1.2.3 存在的问题 ................................................................................................................................ 5 1.3 研究内容与研究方法................................................................................................ 5 1.3.1 研究内容 .................................................................................................................................... 5 1.3.2 研究方法 .................................................................................................................................... 6 1.4 研究特色及研究技术路线........................................................................................ 6 1.4.1 研究特色 .................................................................................................................................... 6 1.4.2 研究技术路线 ............................................................................................................................ 7 2 工程概况 9 2.1 矿井概况.................................................................................................................... 9 2.1.1 基本情况 .................................................................................................................................... 9 2.1.2 地质构造 .................................................................................................................................... 9 2.1.3 水文地质条件 .......................................................................................................................... 10 2.2 下保护层开采条件.................................................................................................. 11 2.2.1 保护层和被保护层主要特征 .................................................................................................. 11 2.2.2 保护层和被保护层瓦斯参数情况 .......................................................................................... 12 2.2.3 下保护层开采最小层间距 ...................................................................................................... 12 2.3 本章小结.................................................................................................................. 15 3 岩石力学参数测试 17 3.1 岩石力学参数测定概述.......................................................................................... 17 3.2 采样地点.................................................................................................................. 17 3.3 试验设备和检测仪器.............................................................................................. 17 3.4 岩石试样的规格、加工精度、数量及含水状态.................................................. 19VI 3.4.1 试样规格.................................................................................................................................. 19 3.4.2 试样加工精度.......................................................................................................................... 19 3.4.3 试样数量及含水状态.............................................................................................................. 19 3.5 岩石物理力学参数测定方法和测定结果 ..............................................................19 3.5.1 岩石视密度测定...................................................................................................................... 19 3.5.2 岩石抗拉强度测定.....................................