上行重复采动底板采空区突水及开采稳定性理论分析

下煤层积水采空区上采用“上垮-下柱”方式复采上煤层带来严重的安全稳定性与底板采空区突水问题。将下煤层煤柱群与承压性空区积水联合支撑的蹬空覆岩简化为半无限平面体,建立合理的力学模型,通过弹性力学求解,得到蹬空覆岩的应力场分布。引入Mohr-Coulomb准则,极值求解得到顶板覆岩最大破坏高度,再结合上煤层开采底板破坏深度,分析重复采动层间岩层稳定性状态,并提出了相应的判别指标。考虑层间隔水控制层与水头损耗,提出不同层间岩层稳定性状态下的突水判据,并揭示水平构造应力对重复开采稳定性的作用。兼顾重复采动稳定性、底板采空区突水、煤柱承载稳定性,给出不同工况条件下的评价方法与防治措施,包括合理的疏水降压措施与煤柱“柱旁充填”指标。研究结果表明:顶板应力场与采深、水平地应力、煤柱宽度、单个空区跨度、空区水压有关,采空区顶板破坏形态大致为“波浪形”;当安全系数T≥1,重复开采稳定性较差,未采取措施不易在上煤层采用长壁式垮落法开采;水压越大,可减轻煤柱承载,并使煤柱处于高围压条件下,煤柱稳定性较高,但高水压又易发生底板采空区突水;煤柱宽度越大,承担的平均支撑力越小,σ_(y)应力峰值越低,层向分布波动越小,σ_(x)应力同样越小,顶板与煤柱越不易发生破坏;侧压力系数大于1且越大,可有效提高上行重复开采的可行性;疏水降压后的水压值p_(1)需同时满足可规避突水与煤柱失稳的条件,即p_(m)<p_(1)<max(p_(f),h_(d)/100+p_(max)),否则需对积水完全疏放,后按照“柱旁充填”尺寸指标W_(m0)对空区进行柱旁充填。研究可为积水采空区上采用“上垮-下柱”安全复采上煤层、防止底板采空区突水、提高资源采出率及减少资源浪费提供有益指导。

某铜矿尾矿库运行和深部开采条件下的稳定性分析

某铜矿的尾矿库所处地质条件复杂,库内水体向下渗透会影响下部开采活动,为了考察尾矿库库区地下水对采矿的影响,采用PLAXIS软件进行地下水数值模拟,建立地表水入渗与地下水渗流场耦合作用模型,研究地下水流场的变化趋势以及对北矿带矿坑充水的影响。结果表明,尾矿堆载仅对库底30m范围内地层的变形有一定的影响,对东阻水体和巷道变形无影响。

矿区开采区稳定性评价及改善措施

针对贵州省某矿区实际开采情况,在简要分析该矿区采空区地表变形特点与成因的基础上,围绕稳定性评价结果与分区特点,提出有效的改善措施,为避让和防治开采区地表变形引发的地质灾害提供参考。

新疆哈密市圪塔山口铜镍矿区工程地质特征

圪塔山口铜镍矿地貌为中—低山区,位于哈密市东南部,区内沟谷交错分布,构造极其发育,本次从矿体、围岩工程地质特征和主要地质出现问题层位等方面,结合岩体力学试验和测试,对矿区工程地质勘查复杂程度综合分析,综上所述认为该矿区工程地质勘查为复杂程度属二类—三类中等型。

Rock mass movements around development workings in various density of standing-and-roof-bolting support

Presented measurement results of roof rocks and wall rock movements of un- derground development workings after their drifting.The research was carried out in the coal mine workings with standing-and-roof bolting support.There were various density of the support,so the aim of the special monitoring programme was to determine movement intensity of rock mass in the premises of the heading area.There were four types of re- search did by the authors.They measured convergence,roof layers separation using tell- tales and sonic probes and load bearing of the headings' roofs by hydraulic dynamometers Evaluation of fracture zone around the heading and investigation the load zone caused by failed roof rocks may become a basement for the determination of support parameters of the workings.The combined system of standing support and roof bolting seems to be an essential for underground headings protection.