复杂隧道线形条件下盾构掘进姿态控制模型研究

Along with the development of the Chinese metro construction and adoption of DC motor driving system, shield tunneling projects at large slope and sharply curved tunnel sections are increasing. Control of shield posture is increasingly prominent for following the complex designed tunnel alignment. Although there are some automatic posture control systems in large shield machines, control of shield posture still rely on experience of shield operators. Since the proficiency level, psychology, and emotional situation of shield operators are different, it is sometimes difficult to control the shield in a complex tunnel alignment. Therefore, it is proposed to develop the operation model of overcut, articulation, and the load model acting on shield during excavation. The operation model is used to calculate copy cutter length and range, and articulated angle based on vector analysis, which is applicable on general compound alignments with three-dimensional curvature. The load model is composed of five forces: force due to the self weight of machine, forces on the shield tail, force due to the jack thrust, force acting at the excavation face, and force acting on the shield skin plate. In the load model, a decoupled model of the cutter head load is established, in which the interaction between the cutter head and the soil on the excavation interface is considered. The coupled system between the cutter head and the soil is considered as two correlative subsystems. Equilibrium differential equations and boundary conditions are established for decoupled analysis. Finally, Kinematics and dynamics equations are established respectively. In order to achieve the control of shield posture purposes, sliding mode controller with exponential approach law and fuzzy adaptive rules is proposed.

随着我国城市轨道交通建设的飞速发展及直线电机驱动地铁系统的采用，大坡度、小半径曲线等复杂线形的地铁盾构隧道工程不断增多，满足复杂隧道设计轴线的盾构掘进姿态控制问题日益突出。目前，尽管在某些大型盾构上装备有自动控制器，盾构姿态控制的现状仍然依靠现场施工人员的经验以人工操作的方式来实现。由于盾构操作人员的熟练程度不等，操作时的心理、情绪状态各异，使姿态控制精度难以维持一致的标准。为此，本项目针对盾构掘进姿态控制这一涉及盾构掘进与土体相互作用数学模型建立与控制算法实现的关键科学问题，通过理论分析与模型试验的方法，提出盾构超挖及铰接角算法、盾构掘进动态荷载模型的研究内容，建立反映地层条件、盾构操作参数和盾构运行状态耦合作用的盾构运动学和动力学模型，并且在盾构运动学和动力学模型的基础上，设计基于指数趋近律及模糊自适应规则，具有良好适应性和稳定性的盾构掘进姿态滑模变结构控制器。

在小曲率半径急曲线段，由于盾构本身为直线形刚体，不能与隧道曲线完全拟合，曲线半径越小，盾构机身越长，则拟合难度越大。此时，盾构主要通过超挖刀（仿形刀）和铰接装置的配合使用及对行进千斤顶偏心推力的控制实现曲线掘进。超挖刀和铰接装置的使用将直接影响超挖量和超挖范围，超挖量和超挖范围过大将严重扰动周围地层，过小将不能充分发挥铰接装置的作用，导致盾构过分挤压周围地层及过大千斤顶偏心推力引起管片破损情况的出现。.对大坡度隧道施工而言，当盾构迎坡向上掘进时，由于盾构自身质量巨大，而外壳表面较为光滑，使得盾构容易发生滑落。当盾构发生滑落时，掘进中的刀盘会与开挖面土体发生脱离，造成开挖面土体的松动变形，从而导致地表沉降的增大。当盾构顺坡向下掘进时，盾构在自身重力沿掘进轴线的分力作用下，容易导致盾构过分挤压开挖面土体，造成地表隆起变形。.由以上分析可见，大坡度小半径曲线等复杂隧道线形条件下盾构掘进是一个非常复杂的土-盾构动态相互作用过程。从影响因素角度看，土-盾构相互作用同地质条件、盾构操作参数及盾构运行状态等诸多因素直接相关，且这些因素之间存在复杂的相互耦合作用。.为实现复杂隧道线形条件下盾构掘进姿态的精细化控制，本项目研究基于空间向量运算及盾构掘进动态荷载模型，开发了一般三维曲线条件下超挖量，中折角，千斤顶推力及偏心力矩模拟研究。本项目依托具有27个曲线段的某盾构隧道工程，选取5个典型曲线段进行数值模拟，给出了急曲线条件下盾构施工参数及掘进参数的预测值，为该项目盾构急曲线连续掘进可行性分析提供了理论依据。.研究结果表明，本项目所提出的一般三维曲线条件下盾构超挖量，中折角，千斤顶推力及偏心力矩算法能满足实际现场需要，能分析复杂线形条件下盾构掘进的可行性。本项目研究成果可作为类似盾构姿态精细模拟及控制的参考。