【作者】 邓孔书；

【导师】 王立平；

【作者基本信息】 清华大学 ， 机械工程， 2010， 博士

【摘要】 推进系统承担着整个盾构的顶进任务,需完成盾构掘进机的转弯、曲线行进、姿态控制以及纠偏。因此,对盾构推进系统的性能分析和设计是实现整个盾构系统正常工作的关键。本文针对土压平衡盾构推进系统关键特性理论,重点在力传递特性、基于变刚度的变形特性和固有频率特性等方面进行了系统的研究,并应用研究理论对工程中使用的盾构推进系统进行了布局优化设计。最后完成了一套缩尺直径628mm盾构切削推进实验平台的尺寸综合与设计。研究了盾构推进系统力传递特性。以推进液压缸作用在管片上的顶推力均匀为原则,构建出推进系统力学模型,得到基于拉格朗日函数的力传递方程。通过对拉格朗日函数求解分析,分别构建了均匀系统、四分区系统以及非均匀系统力传递椭圆模型。以力传递椭圆偏心率做为系统力传递性能指标,分别分析了各类推进系统的力传递特性,寻求出适应不同地质条件的推进系统液压缸布局类型。在分析盾构推进系统刚度特性的基础上,研究了推进系统的变形特性。基于超静定变形理论,应用变形协调方程,构建了推进系统的变形椭圆模型。以推进系统变形椭圆模型为基础,将系统液压缸中最大变形量和变形差作为系统变形指标,分析了均匀布局推进系统和非均匀布局推进系统的变形特性。给出了多套推进系统在掘进过程中,变形对系统姿态控制精度的影响情况。提出采用推进系统固有频率线的方法研究系统振动性能。首先构建了推进系统振动模型,并以该模型为基础,推导出系统固有频率方程,利用固有频率特征方程解的特性,导出推进系统的固有频率线。最后将频率线,应用到实际的盾构推进系统中,分析了均匀系统与多套非均匀系统固有频率特性,获得各套系统防止共振现象的固有频率段,为在盾构设计中避开共振频率提供了理论基础。根据力传递及变形特性等方面的研究基础,进行了直径6.34m盾构推进系统二十二台液压缸的布局优化设计。该设计以力传递最优为基本原则,兼顾考虑推进系统变形最小和避开系统共振现象。最后以相似理论为基础,按照四液压缸推进系统的优化布局结果,设计和搭建了对应的四液压缸缩尺盾构切削推进实验平台。更多还原

【Abstract】 The shield thrust system in machines, driven by hydraulic systems providing large forces, is a key part of the shield machine. It does not only perform the task of driving shield ahead in the process of tunneling, but also control the attitude of the machine to ensure that the machine can advance along the expected path consequently for constructing the planned tunnel line. Therefore the rational analysis and design for thrust system plays an important role in the whole machine which can work well. In this paper, the key characteristics theories for driving system in Earth Pressure Balance (EPB) shield machines emphasizing on the characteristics of force transmission, deformation and natural frequency under variable stiffness were investigated. According to the characteristics above, the layout for thrust system applying in engineering was optimized. Finally, the dimensional design for reduced-scale model with diameterΦ628mm was given.The characteristics for force transmission were researched. Based on the mechanical model for driving system, the optimization function was introduced for the uniform force on segments which will be cracked by large thrust. Through analysis of the Lagrange function, the even, the four-group and the uneven systems force spatial ellipses were constructed. After eccentricity for force spatial ellipse being regarded as force performance index, the force transmission characteristics for three kinds of systems were intensively studied to seek the kind of thrust system which is suitable for the given geological condition.On the ground of the analysis for properties on stiffness for thrust system, the characteristics for deformation were studied. Base on hyperstatic compatibility, the spatial deforming ellipse for the driving system has been discovered. Applying the model to the thrust systems, the characteristics for the deforming ellipse of even and non-uniform arrangement systems have been analyzed in detail under variable stiffness caused by the compressibility of oil in hydraulic cylinders. The deformation for several kinds of thrust systems which has the effect on the control precision was given.The mothed of adopting frequency line to study the vibrational characteristics in driving systems was proposed in paper. In the light of changing rate in thrust system with the extension of hydraulic cylinders, the model of vibration was built. Through the model, the frequency line for thrust system was discovered in the progress of solving eigenvalues for feature matrix. Applying the frequency line to the thrust system in engineering application, the natural frequencies in three directions for the even system and uneven system were analyzed. The ranges of natural frequency in thrust systems have been obtained to provide the theoretical foundation for avoiding the resonanceOn the basis of the characteristics above, the optimization layout for the thrust sytem with diameter 6.34m was given. Consdering the minimum deformation and avoiding the resonance, the basic principle for the design is good force transmission performce. Finally, in line with the similarity theories, the reduced-scale shield cutting and thrust system in which the layout for jacks was optimized were designed and put up. Keywords: EPB Shield Machines; Thrust System; Spatial Force Ellipse; Variable Stiffness; Natural Frequency更多还原