【作者】 张春阳；

【导师】 曹平；

【作者基本信息】 中南大学 ， 采矿工程， 2013， 博士

【摘要】 摘要：随着国民经济发展,国内铝土矿的需求也越来越大。铝土矿多以露天开采为主,随着地表易采铝土矿资源的日益枯竭,复杂地质条件下的铝土矿地下开采也逐渐成为铝土资源开发的重要组成部分。本文以三门峡铝土矿地下开采为例,开展复杂地质条件下的巷道掘进、支护稳定性研究。三门峡铝土矿矿体隐伏于河床之下,虽然对河流进行了改道,但是矿区地质条件特别复杂,包括软弱页岩、断层、灰岩破碎带等严重影响了巷道施工速度。因此,为了解决困扰三门峡铝土矿巷道掘进、支护遇到的难题,提高巷道施工速度,本文结合已有相关研究资料,采用地质调查与探测、室内岩石力学实验、理论分析、数值模拟、现场试验等方法,综合分析了影响矿区巷道稳定性的主要因素。最后针对矿区巷道掘进、支护面临的主要问题,提出了相应的研究方案,本文主要研究内容和成果如下：1、通过现场调查与探测,获取了掌子面前方不良地质体的分布特征,对矿区主要围岩进行了回弹强度测试,评价了矿区围岩Q值范围,采用瞬变电磁仪、TRT6000对矿区不良地质体进行了超前探测和分析；提出了TRT6000结合少量超前钻的联合超前预报方案,为不良地质条件下巷道施工提供保障。调查发现影响雷沟矿区2号回风井、3号罐笼井的主要问题是灰岩破碎区、页岩软弱区及断层破碎带,7号井主要问题是页岩软弱区、溶洞及地下水。2、通过现场取样,在室内加工岩样后,采用分级增量循环加卸载的方式研究矿区主要围岩蠕变性质,理论分析了围岩蠕变损伤机理及微裂纹扩展规律,结合实验数据推出了围岩蠕变经验模型。将围岩蠕变总量细分为瞬时弹性应变εme瞬时塑性应变εmp、黏弹性应变εce和黏塑性应变εcp,根据各蠕变分量特征,提出了改进的伯格斯(Burgers)流变模型。采用最小二乘法分别辨识了经验模型和改进的伯格斯(Burgers)模型蠕变参数,实验数据拟合验证了模型的正确性,为巷道变形数值模拟研究提供了帮助。3、理论分析了巷道开挖应力和位移演化规律,结合流变力学基本原理,同时也分析了巷道粘弹塑性力学特征。针对矿区巷道掘进、支护中存在的主要问题,选取巷道掘进时遇到的典型地质条件为研究对象,通过MIDAS-GTS建立模型,再导入FLAC3D进行巷道开挖稳定性计算。计算结果表明,巷道穿越的不良地质体中部区域围岩变形最大,应力也最为集中,可见该位置属于巷道稳定性最差的薄弱区域；对于稳定性差的薄弱区域,可以考虑适当增加支护体强度,并及时支护。施工时首先采用TRT6000结合部分超前钻,探明不良地质体沿巷道走向的长度,确定巷道最薄弱区域位置,用于指导巷道掘进和支护施工。4、结合数值模拟分析和当前已有支护方式,在确保巷道稳定的前提下,为了加快巷道掘进、支护速度,提出了以钢纤维喷射混凝土为主的联合支护方式,替代施工速度较慢的砌碹支护以及锚喷网支护中的钢网,薄弱区域可以适当考虑安装锚杆。现场工业试验表明,采用钢纤维喷射混凝土支护不仅能够确保围岩稳定,而且也提高了施工速度,具有应用的可行性,可以根据围岩实际情况选择合理的喷射厚度。最后,针对泥化页岩区域的巷道掘进、支护难题,在结合当前施工方案的基础上,提出了新的钢钎棚支护方式,该支护方式不仅具有超前支护效果,而且能够和二次支护一起形成整体式支护结构。更多还原

【Abstract】 Abstract:With the development of national economy, domestic demands of bauxite become more and more large. Bauxite is generally exploited by open-pit mining, with surface and easy mining resources are depleted, underground mining under complicated geological conditions has gradually become an important part of bauxite resource development. In this paper, San Men xia bauxite underground mine is taken for example, roadway excavation and support stability studies are carried out under complicated geological conditions. The ore body is buried under the riverbed, although the river course is changed, but the mine geological conditions is complicated, weak shale, fault, limestone fracture zone etc, have a serious impact on the speed of roadway construction. Therefore, in this paper, in order to solve roadway excavation and support problems, improve roadway construction speed, after consulting relevant research data, the main factors which affect the stability of roadway are comprehensively analyzed by geological survey and exploration, indoor rock mechanics experiments, theoretical analysis, numerical simulation and field tests. Corresponding research program which is aimed to solve the problems of roadway excavation and support has been proposed, the main research contents and results are shown as follows:(1) Distributions of adverse geological body which is ahead of working face are obtained by on-site investigation and detection, surrounding rock rebound strength tests are conducted, rock Q values are evaluated, advanced detection and analysis are carried out by TRT6000and TEM instrument. A new advanced prediction program which is consist of TRT6000and less advance drill is proposed, the new program will provide effective protection for roadway construction under adverse geological conditions. Survey results show that major problems which effect2th and3th shaft are limestone crushing area, shale weak areas and fault fracture zone, and the problems which is7th shaft faced with are shale weak areas, caves and groundwater.(2) After field sampling and samples processing, creep properties of main surrounding rock are studied by graded incremental cycle way, rock creep damage mechanisms and micro-crack propagation law are theoretically analyzed, rock creep empirical model is derivated by the experimental data. Rock total creep strain can be subdivided into instantaneous elastic strain εme, instantaneous plastic strain emp, viscoelastic strain εce and viscoplastic strain εcp, according to each creep component characteristic, an improved Burgers (Burgers) rheological model is proposed. Parameters of empirical model and improved Burgers model are identified by the method of least squares, the correctness of the model is verified by experimental data fitting, and it will help for roadway deformation numerical simulation.(3) Roadway excavation stress and displacement evolutions are analyzed theoretically, then according to the basic principles of rheology, mechanical analysis of viscoelastroplasticity is carried out for roadway stability. Faced with the main problems of roadway excavation and support, typical geological conditions are taken as research object, The model is established by MIDAS-GTS and imported to FLAC3D for calculation. The results show that maximum deformation and stress most concentrated area is located in the middle of adverse geological body which roadway pass through, and the location is also the worst stability area. For these areas, the support body strength increase and timely support measures should be appropriately considered. At first adverse geological body length which is along roadway direction will be detectd by TRT6000and some advanced drilling, so that the weakest area location of roadway will be identified for roadway excavation and support construction.(4) According to numerical simulation analysis and current support method, under the condition of ensuring roadway stability, in order to speed up roadway excavation and support, combination support method which is mainly with steel fiber shotcrete is proposed, the new method is used to replace cast-in-situ concrete support and the steel mesh, bolts will be properly considered in weak areas. Field industrial tests show that the stability of surrounding rock is ensured, construction speed is improved, it can clearly be seen that the new method have important application feasibility, reasonable spraying thickness will be choosen according to the actual situation of surrounding rock. Finally, for clay shale region, based on the current construction program, a new drill rod shed support method is proposed, the support method not only has advance support effect, but can also form a whole supporting structure together with secondary support.更多还原