TBM盘形滚刀破岩机理的试验与模拟研究

发布时间：2018-09-07 08:41

【摘要】：刀破岩效果的好坏直接关系到TBM施工的掘进效率、工程进展以及经济效益。研究盘形滚刀破岩机理,分析滚刀与围岩的相互作用形式,对于改进刀具设计、提高破岩掘进效率都具有十分重要的理论和现实意义。基于上述背景,本文对盘形滚刀与岩石相互作用形式进行了深入研究,以期进一步揭示滚刀破岩机理及裂纹扩展规律。本文的主要内容和研究成果有： (1)基于岩石切削扩展模型,运用断裂力学理论研究了滚刀作用下裂纹扩展问题,得到了围压的增长抑制了中间裂纹扩展并使得侧向裂纹断裂角增大的结论,从理论角度揭示了围压与滚刀作用下裂纹扩展的关系。 (2)自主设计改装了TBM冲击破岩试验平台,采用花岗岩与水泥砂浆材料制备了完整试件与多种类型的节理试件,运用试验平台开展了多围压水平下的滚刀破岩试验。分析了滚刀作用下岩体破碎特征,发现拉应力在滚刀破岩过程中起主导作用。研究了岩体破碎模式以及破岩载荷、岩石破碎面积与围压的关系,探讨了岩石节理特征对滚刀破岩的影响。 (3)运用颗粒流数值模拟软件PFC构建了盘形滚刀破岩模型,从细观角度分析了滚刀作用下岩石的破碎过程以及裂纹扩展规律,对不同工况下滚刀载荷、裂纹分布形式、裂纹扩展路径以及裂纹数量等进行了深入研究,模拟结果表明,围压较低时,岩石呈现以张拉破坏为主的拉剪综合失效模式,围压的增长使得岩石破坏模式逐渐过渡为以剪切破坏为主的拉剪综合失效模式。分析了不同围压及刀间距下的破岩比能耗,得到了最优刀间距随围压的变化趋势。
[Abstract]:The effect of cutting rock is directly related to the tunneling efficiency, engineering progress and economic benefit of TBM construction. It is of great theoretical and practical significance to study the rock breaking mechanism of disc hob and analyze the interaction between hob and surrounding rock, which is very important for improving the tool design and improving the driving efficiency of rock breaking. Based on the above background, the interaction between disc hob and rock is studied in this paper in order to reveal the mechanism of rock breaking and the law of crack propagation. The main contents and results of this paper are as follows: (1) based on the rock cutting growth model, the crack propagation problem under the action of hob is studied by using fracture mechanics theory. It is concluded that the increase of confining pressure inhibits the growth of intermediate crack and increases the fracture angle of lateral crack. The relationship between confining pressure and crack propagation under the action of hob is revealed theoretically. (2) TBM impact rock breaking test platform has been designed and modified independently, and complete specimens and various types of joint specimens have been prepared by using granite and cement mortar materials. The rock piercing test of hob at multi confining pressure level was carried out on the test platform. The fracture characteristics of rock mass under the action of hob are analyzed, and it is found that tensile stress plays a leading role in the rock breaking process of hob. The fracture model of rock mass and the relationship between rock breaking load, rock fracture area and confining pressure are studied, and the influence of rock joint characteristics on rock breaking with hob is discussed. (3) using the numerical simulation software PFC of particle flow, a rock breaking model with disc hob is constructed. In this paper, the fracture process and crack propagation law of rock under the action of hob are analyzed from a mesoscopic point of view. The load of hob, the distribution of crack, the path of crack propagation and the number of cracks under different working conditions are studied in depth. The simulation results show that, When the confining pressure is low, the comprehensive failure mode of tension and shear is the main failure mode of rock, and the increase of confining pressure makes the failure mode of rock gradually transition to the comprehensive failure mode of tension and shear which is dominated by shear failure. The energy consumption of rock breaking under different confining pressure and tool spacing is analyzed, and the variation trend of optimal tool spacing with confining pressure is obtained.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.3

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