短壁块段式采煤覆岩导水裂隙发育力学特性分析

短壁块段式采煤技术作为一种绿色开采技术,可以有效地兼顾煤炭安全高效开采和水资源保护,但在开采过程中会造成一定范围的导水裂隙带,对含水层的稳定性造成潜在的影响。因此,短壁块段式采煤覆岩导水裂隙发育力学特性的研究对科学预防、控制和治理煤炭开采所引起的水资源流失问题具有重要意义。为了计算短壁块段式采煤造成的覆岩导水裂隙带发育高度,在分析覆岩移动特征的基础上,确定影响短壁块段式采煤覆岩导水裂隙发育的主控因素。并基于弹性地基梁理论,结合短壁块段式采煤工作面布置特殊性,建立了一种计算短壁块段式采煤覆岩导水裂隙带发育高度的弹性地基叠合梁力学模型,给出岩层产生导水裂隙的判定方法,计算获得岩层破坏层数(导水裂隙带高度)随不同主控影响因素的变化规律,揭示了短壁块段式采煤覆岩导水裂隙发育的力学机理及规律。研究结果表明:随着采高和块段长度增大,岩层破坏高度呈阶梯状上升;随煤柱宽度的增加,岩层破坏高度呈降低趋势。同时,当影响因素参数在一定范围内时,岩层破坏层数不变,因此,在保证水资源不发生流失的前提下,可选择范围内最大采高、块段长度以及最小煤柱宽度作为开采指标来提高回收率。现场短壁块段式采煤实验工作面采用钻孔冲洗液漏失量观测和钻孔电视探测的方法,测试得到采动造成的覆岩导水裂隙带高度约为50.06 m,与理论计算结果(50.3 m)基本吻合。

Analytical solutions of hard roof's bending moment,deflection and energy under the front abutment pressure before periodic weighting

The distribution of front abutment pressure is closely related to the force,deformation and energy distribution of hard roof before periodic weighting. So it is necessary to carry out research on the relationship between them. According to front abutment pressure distribution feature,using the location of peak front abutment pressure as the dividing point,coal seam is divided into two parts along the direction of mining: the yield zone that is the area between the faceline and the point where the maximum front abutment pressure occurs,and the elastic zone that is the part before the point of peak front abutment pressure. The proposed mechanical model of unit width hard roof at the panel center before periodic weighting consists of five parts including the yield zone. All parameters of the deflection equations for each of the five parts that satisfy the continuity conditions and natural boundary conditions are obtained by using the Matlab software. The continuous curves of front abutment pressure,deflection,bending moment and bending strain energy density distribution of hard roof are obtained by iterative approximation method,and the relationship between the yield zone width and the above curves are analyzed in detailed.

Study on first caving fracture mechanism of overlying roof rock in steep thick coal seam

Based on the elastic plate theory, a mechanical model of thin plate for the first caving of overlying roof rock in steep mining face was established. The analytical solution of the deflection and stress distribution of roof rocks was obtained. According to the specific geological conditions of the 5-103 panel in Shanxi,the failure of roof rocks and the influence of seam dip on it during the exploitation were theoretically investigated. Meanwhile, the first caving characteristics of the overlying rock in the steep coal seam were investigated based on its stress contour. The results show that the dip angle has a distinct influence on the caving interval and the first caving interval for the 5-103 panel is 37 m in theory. Finally, a systematic monitoring on the behavior of rock pressures was conducted. The measured results agree well with the theoretical prediction, which provides a good reference for practical steep coal seam mining.

Failure laws of narrow pillar and asymmetric control technique of gob-side entry driving in island coal face

In allusion to the problems of complex stress distribution in the surrounding rock and deformation failure laws, as well as the difficulty in roadway supporting of the gob-side entry driving in the island coal face, 2107 face in Chengjiao Colliery is researched as an engineering case. Through physical mechanical test of rock, theoretical and numerical simulation analyses of rock, the analysis model of the roadway overlying strata structure was established, and its parameters quantified. To reveal the deformation law of the surrounding rock, the stability of the overlying strata structure was studied before, during and after the roadway driving. According to the field conditions, the stress distribution in coal pillar was quantified, and the surrounding rock deformation feature studied with different widths of the pillars in gob-side entry driving. Finally, the pillar width of 4 m was considered as the most reasonable. The research results show that there is great difference in support conditions among roadway roof, entity coal side and narrow pillar side. Besides, the asymmetric control technique for support of the surrounding rock was proposed. The asymmetric control technique was proved to be reasonable by field monitoring, support by bolt-net, steel ladder and steel wire truss used in narrow pillar side.

煤矿采动空间CO_(2)地质封存、运移与固化理论和技术框架

“碳达峰、碳中和”是煤矿行业转型的重大机遇与严峻挑战。我国因煤炭资源开发产生了规模巨大的地下空间资源,结合煤矿行业绿色开发的切实需求,聚焦煤矿采动空间的资源化利用,基于我国煤系沉积岩地质盖层概况与CO_(2)理论封存能力,提出煤矿采动空间CO_(2)地质封存、运移与固化理论和技术框架。该理论的核心科学问题是CO_(2)-水-煤系沉积岩相互作用机理与CO_(2)采动空间的运移规律;亟待解决的关键技术包括:煤系沉积岩地质盖层保护性开发与盖层人工修复技术,基于多功能测井的CO_(2)高效示踪技术,采动空间CO_(2)矿化辅料研发,矿井水污染监测、识别与处理技术。研究煤系沉积岩地质盖层封存能力影响因素,揭示CO_(2)采动空间运移规律,分析CO_(2)采动空间多场多相耦合作用机理,掌握CO_(2)封存工况条件下的矿井水水质演变特征,形成时空尺度上的采动空间CO_(2)地质封存、运移与固化规划理论和体系,提高其技术经济合理性。实现煤矿采动空间CO_(2)地质封存、运移与固化,助力煤矿企业对煤系资源充分开发,增加我国碳封存潜力与封存路径,经济社会效果显著。

短壁块段式充填采煤矸石充填材料重金属离子“下行”迁移规律及控制技术

现阶段煤炭开采产生的废弃矸石广泛利用于矿山充填领域,然而矸石内部重金属离子对矿区水资源产生的潜在污染风险愈发突出。结合短壁块段式充填采煤技术,综合分析重金属离子析出与迁移的敏感性因素,建立矸石充填材料重金属离子“下行”迁移模型,揭示矸石充填材料重金属离子“下行”迁移规律,提出重金属离子“下行”迁移控制技术。研究表明:矸石粒径、煤层埋深、底板岩性以及重金属离子析出浓度是关键性影响因素,且重金属离子迁移距离随底板岩层的渗透率及重金属离子析出浓度的增大而增大,随矸石粒径及煤层埋深的增大而减小,确定底板岩层的渗透率及重金属离子析出浓度为核心影响因素。提出了重金属离子“下行”迁移控制技术,包括顶板注浆封堵技术、底板铺设防渗层技术、pH值调控技术以及矸石粒径控制技术。

基于机器视觉的煤尘环境下掘进空间煤岩界面感知与精准识别

巷道掘进过程中煤岩识别技术是掘进机截割头自动调整的核心,同样是制约矿山智能化建设的关键难题之一。针对当前采掘失衡,掘进工作面缺乏成熟有效的煤岩识别方案,现有基于图像的煤岩识别模型存在分割精度差、无法灵活部署等问题,提出一种应用在掘进工作面下基于图像分割的煤岩截割界面感知与精准识别方法。该方法结合掘进工作面实际截割情况,采用Mobile-NetV2特征提取网络作为DeepLabV3+的主干网络,使模型更好地兼顾分割精度和模型复杂度;将空洞空间卷积池化金字塔模块输出的高级特征进行通道注意力(SE)操作,分配通道权重以强化对重点特征信息的训练;在主干网络输出的浅层特征引入通道空间注意力(CA)机制,使浅层特征图中的低级表征信息加权,从而设计出融合双注意力机制于DeepLabV3+的煤岩截割界面识别模型。同时搭建煤尘环境下煤岩识别实验平台模拟掘进机截割后形成的煤岩截割面,研发巷道掘进过程中煤岩截割界面采集方法,并以实际矿井的掘进工作面为工程背景,验证该煤岩识别模型的分割精度以及实际应用性。研究结果表明:SE-CA-DeepLabV3+模型的平均交并比和平均像素精度分别为97.15%和98.51%,相较于其他模型具有更优的分割性能。将所建立模型对来自陕北试验矿井掘进工作面的原始煤岩图像进行验证,平均误差为0.7%,每秒传输帧数为43 fps,满足井下现场应用部署条件。

短壁块段式充填采煤覆岩导水裂隙发育机理及控制研究

针对矿区开采遗留的"三下"压煤、边角煤柱、工广煤柱以及不规则块段等煤炭资源的回收问题,同时为解决矸石堆积危害和煤炭开采造成的水资源流失,提出采用短壁块段式充填采煤技术回收该资源。为了准确地计算短壁块段式充填开采造成的导水裂隙带发育高度,在分析块段式充填开采工艺特点和上覆岩层移动特征的基础上,采用弹性地基梁理论,建立了一种计算块段式充填采场覆岩导水裂隙带高度的力学分析模型。以现场实验区域为例,研究得到实验工作面导水裂隙带高度不发育至含水层的最小煤宽度柱和采空区充实率分别为5 m和65%;鉴于此,现场设计保护煤柱宽度为5 m,充实率为80%。