巷道围岩离层下锚杆荷载传递机理及支护设计研究

发布时间：2018-04-09 00:08

本文选题：巷道　切入点：层状岩体　出处：《西安科技大学》2016年博士论文

【摘要】：随着煤矿生产规模的不断扩大以及大型机械设备的广泛使用,为满足生产运输要求,煤矿巷道断面尺寸随之不断增大。由于煤矿巷道顶板多为层状沉积岩,巷道尺寸增大会使围岩产生较大变形,在顶板处易产生离层,由此引发的巷道支护问题亟待解决。传统的支护设计方法均将围岩视为连续均质介质,未考虑离层的不利影响,本文在分析和总结现有锚固支护理论、锚固界面力学机理研究现状及存在问题的基础上,考虑锚固支护岩体的复杂性,特别是层状岩体中巷道开挖引发的离层对锚杆荷载传递规律的影响,利用理论分析、现场试验及数值模拟等方法,开展了以下几方面的研究。基于离层的产生机理对离层进行分类,分析巷道离层型顶板的特征,给出离层位置和离层值的理论估算方法及试验确定方法。根据柠条塔N1205工作面地质条件,对离层位置及离层值大小进行综合判断,为考虑离层条件下的锚杆支护设计打下基础。分析离层作用下的锚杆荷载传递机理,基于剪切滑移模型,分别建立单离层条件下垂直锚杆和倾斜锚杆,以及多离层条件下锚杆荷载传递的弹塑性力学模型,得出离层作用下锚杆应力分布的表达式,总结出离层发展过程中锚杆荷载的变化规律,并对不同离层值、离层位置、锚杆与离层夹角等参数影响下的锚杆受力特性做系统分析。设计室内模型试验,研究离层对锚杆的荷载作用,得出岩体裂缝扩展过程中锚杆的应力分布规律及裂缝张开量值与杆体荷载的关系,将试验结果与理论计算值进行对比分析,验证理论模型的正确性及适用性。运用二维离散元软件对非均质岩体中锚杆的受力状态进行数值模拟,并对影响参数进行规律性分析。分别建立考虑离层影响的全长粘结型锚杆以及局部锚固锚杆的力学模型,对系统锚杆进行受力分析,综合理论计算和数值模拟结果,分析获得离层岩体中锚杆的荷载分布规律。通过系统锚杆荷载求解,对已有的锚杆支护设计进行安全性评价,并为含有离层情况的锚杆支护设计提供理论依据。将研究成果应用于陕北柠条塔煤矿N1205工作面胶运顺槽支护设计中,对比传统的支护设计方法,发现考虑离层影响后的锚杆荷载超过承载力设计值,原有的支护参数不能满足安全要求,需对参数进行调整,通过系统锚杆荷载求解,对锚杆直径、间排距及锚固长度进行重新设计,并对预紧力的合理取值进行讨论。现场监测结果表明考虑离层情况的锚杆支护设计方法更安全合理。
[Abstract]:With the continuous expansion of the scale of coal production and the extensive use of large-scale machinery and equipment, in order to meet the requirements of production and transportation, the section size of coal mine roadway is increasing.Because the roof of coal mine roadway is mostly stratified sedimentary rock, the increase of roadway size will result in large deformation of surrounding rock and easy to be separated at the roof, so the roadway support problem should be solved urgently.The traditional support design method regards the surrounding rock as the continuous homogeneous medium without considering the adverse effect of the separation layer. This paper analyzes and summarizes the existing bolting support theory, the research status and the existing problems of the mechanical mechanism of the anchor interface.Considering the complexity of bolting rock mass, especially the influence of roadway excavation in layered rock mass on the load transfer law of anchor rod, the following aspects are studied by means of theoretical analysis, field test and numerical simulation.Based on the formation mechanism of the separation layer, this paper classifies the separated layer, analyzes the characteristics of the roof of the roadway separation layer, and gives the theoretical estimation method and experimental determination method of the location and value of the separation layer.According to the geological conditions of Caragana Tower N1205 working face, the location and value of the separated layer are comprehensively judged, which lays a foundation for the design of bolt support under the condition of considering the separated layer.Based on the shear slip model, the elastic-plastic mechanical models of the load transfer of the anchors under the condition of single and inclined anchors are established, respectively, and the load transfer models of the anchors under the condition of multi-layer separation are analyzed, and the elastic-plastic mechanical models of the load transfer of the anchors under the condition of multi-layer separation are established, respectively.The expression of the stress distribution of anchor rod under the action of separation layer is obtained, and the variation law of bolt load during the development of separation layer is summarized, and the mechanical characteristics of anchor rod under the influence of different values, location and angle between anchor rod and layer are analyzed systematically.The model test in the design room is carried out to study the load action of the free layer on the anchor rod. The stress distribution law of the anchor rod and the relationship between the crack opening value and the load of the bolt body are obtained during the crack propagation of rock mass, and the test results are compared with the theoretical calculation value.Verify the correctness and applicability of the theoretical model.The stress state of anchor rod in heterogeneous rock mass is numerically simulated by using two-dimensional discrete element software, and the regularity of influencing parameters is analyzed.The mechanical models of the full-length bonded anchor rod and the local anchoring bolt considering the influence of the separation layer are established respectively. The load distribution law of the anchor rod in the separated rock mass is obtained by combining the theoretical calculation and the numerical simulation results.The safety evaluation of the existing bolt support design is carried out through the solution of the system bolt load, and the theoretical basis is provided for the bolt support design with the condition of separation.The research results are applied to the support design of the rubber transport channel in the N1205 face of Caragana Tower Coal Mine in North Shaanxi. Compared with the traditional support design method, it is found that the load of the bolt considering the influence of the separation layer exceeds the design value of the bearing capacity.The original support parameters can not meet the safety requirements, and the parameters need to be adjusted. The diameter, spacing and length of anchors are redesigned through the solution of the system anchor load, and the reasonable value of pre-tension force is discussed.Field monitoring results show that the design method of bolt support is more safe and reasonable.
【学位授予单位】：西安科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TD353.6

【参考文献】