【作者】 陈晓辉；

【导师】 慕青松；

【作者基本信息】 兰州大学 ， 固体力学， 2007， 硕士

【摘要】 金川镍矿矿床规模巨大，矿石储量丰富，在国民经济建设中处于战略地位，国家对金川矿山的重视程度在全国独一无二。金川矿区岩体破碎、地应力大、矿体形状变化大，对矿山基建巷道开挖带来严峻挑战。近年来，随着开采深度的逐年增加，巷道的稳定性问题越来越严重，特别是在回采1178分段时，巷道变形量大、变形快，以至不能给二次支护留出足够的时间，严重影响了施工质量与开采进度。本文针对矿区出现的上述生产难题，结合《金川二矿区1150中段水平矿柱回采前后应力场分布规律及安全评估》课题，将岩石力学及地下工程理论与工程实践相结合，以金川二矿18行线剖面为研究对象，运用现场调查、理论分析、计算机模拟等多种研究方法，对复杂地质水文条件、高地应力环境、特殊采矿方法等共同作用下沿脉巷道的破坏机理，以及1178标高巷道的破坏比其他标高巷道更为严重的现象，进行了研究并获得以下重要认识：二矿区在应用大面积不留矿柱回填采矿工艺时，开拓出不同标高的两个采矿平面，其间为水平矿柱，矿体上盘围岩中从上到下依次分布着各标高沿脉巷道。有限元模拟研究表明，水平矿柱的“抵顶”作用是造成1178标高巷道破坏比其他标高更为严重的主要原因。在水平矿柱的屈服破坏来临之前，逐渐变薄的水平矿柱的应力集中程度将越来越高，导致“抵顶”作用越来越强烈，相应地1178巷道的破坏也趋于恶化，但当水平矿柱破坏之后，“抵顶”作用会逐渐弱化，巷道破坏也会相应减轻。受抵顶作用的巷道破坏形式可概括为：先从钢筋混凝土支护的拱顶、拱肩、底角获得突破，随着这些特殊部位的破裂，钢筋混凝土支护内所储藏的能量及地应力使得破裂继续扩展，最终导致整个钢筋混凝土支护的失效，引起巷道周围局部应力场重分布，结果锚杆支护上的有效应力显著增加并超越了其承载强度，于是锚杆在该应力状态下迅速走向破坏并最终失效。随着钢筋混凝土支护和锚杆支护的次第破坏，巷道的联合支护体系彻底崩溃，失去支护维持的巷道围岩将发生剧烈的变形和破碎，出现有害的松动和塌落，并很快充塞巷道的整个有效截面。所以需要加强联合支护体系中各种支护类型破坏次序的研究，为支护体系的优化设计与施工提供新思路。该论述在作者查阅的有关金川矿山的文献中尚无类似报道，对矿区采准工程的设计与施工具有参考价值和指导意义。更多还原

【Abstract】 Jinchuan nickel mine with enormous mineral deposit and riched rare metals is strategic importance for the national economy, so the central government has paid great attention to its development. However, there are some serious problems in Jinchuan nickel mine, such as broken rock, high geo-stress and shape-distorted ore-bodies, etc., which bring about grave challenges to mineral drift excavation. In the No.2 mining area, by the drifts distributed at different altitudes among hanging-wall rock, the backfilled mining in large hypogeal area without micro-jambs has been carried out at two different altitude mining planes for many years, which results in the appearance of the macro-horizontal jamb between the two mining planes. Recently, with the increasing depth of mineral drift excavation, the drift stability has gradually become an eye-attracted focal problem, especially the more remarkable deformation in excavating the 1178m drift resulted in no enough time for repeated shoring, which greatly affects the progress of mine construction.In the implementation of the project "Effects of Macro-Horizontal Jamb Mining on the Redistribution of Stress Field and the Evaluation of Drift Stability in No.2 Mining Area of Jinchuan Nickel Mine", based on considering the interaction of complicated geohydrologic condition, high geo-stress and special mining method, and using various research methods, especially the finite element simulation, and also including spot investigation, theoretical analysis, we have studied the destroy mechanism of the following-vein direction drifts, and obtain some results as followings:The counteractive effect is the main reason of the 1178m drift breakage. Before the approach of the Macro-horizontal jamb failure, the increasing stress concentration with ceaseless mining in mechanized panels of the macro-horizontal jamb makes the counteractive effect become much stronger, which continually deteriorate the breakage of 1178m drift. After the Macro-horizontal jamb destroyed, the counteractive effect will gradually weaken, consequently, breakage of drift also will weaken. The damage forms of drifts are summarized as follows: The damage starts at the vault, spandrels and bottom which are supported by the reinforced concrete. With the breakdown of these special parts, the stored energy and geo-stress within the reinforced concrete support make the break continue expansion, and finally leads to a whole failure of the reinforced concrete support, so causes the redistribution of the localized stress around drift, as a result, the effective stress on the bolts increase significantly and exceed their bearing stress, which make bolts rapid destroy and total failure. The joint support system of drift completely collapse with the destruction of reinforced concrete and bolts, and then the wall rock with destroyed support will appear dramatic deformation, leading to harmful relaxation and slippage of rocks, which quickly fills up the entire drift effective cross-section. Therefore, it is essential to focus on the study of the different damage times in the various support types, which can provides new ideas for the optimized design of the joint support system. These findings and thoughts should be of great reference value for Jinchuan No.2 mining area by reason of. no similar reports in now literatures.更多还原