某型土压平衡式盾构机刀盘的力学分析与结构优化

发布时间：2018-06-22 05:12

本文选题：土压平衡式盾构机 + 刀盘　；参考：《兰州交通大学》2017年硕士论文

【摘要】：近年来,作为地下隧道的主要挖掘工具,盾构机正在我国铁道、公路、地铁工程的建设中发挥着难以替代的作用。由于盾构机的掘进效率在很大程度上受到其刀盘结构的影响,因此对各型盾构机的刀盘结构进行力学分析与优化设计就有着非常重要的意义。本文以兰州地铁线路施工所用某型土压平衡式盾构机的刀盘结构为研究对象,通过对其在正常工况、最大推力工况以及静启动脱困工况下静强度、刚度、疲劳强度、固有频率等力学性能参数的分析,提出了针对其结构进行改进优化的建议。本文首先应用ANSYS Workbench软件分析了刀盘结构在正常工况下的力学性能。根据所得出的等效应力、总变形量与名义疲劳寿命云图,判定出该型盾构机刀盘上静强度与疲劳强度最弱的部位位于牛腿靠近面板背面的外角点位置,而其刚度相对较弱的部位则位于两块未开出渣口面板的外边缘。其次,针对现用刀盘存在的不足提出了改进设计方案。通过对改进后的刀盘结构进行分析,发现在刀盘开口率从35%变至37%的情况下,该刀盘强度最弱部位在正常工况下的静强度与名义疲劳寿命可分别提升37%与221%,而面板外边缘处的变形量则可降低约15%。第三,在静力学分析的基础上对改进前后的刀盘进行了动力学分析,得到了刀盘的振型云图、前六阶固有频率、幅值最大处的频率以及最大幅值。计算表明改进前后刀盘的低阶固有频率由原来的35.58 Hz增大至36.89 Hz,Z轴方向上的最大幅值由47.93 mm减小至46.05 mm。最后,采用多目标优化法对刀盘结构的主要尺寸进行了优化设计。通过以改进后刀盘的最大等效应力σi max、总变形量emax和刀盘质量m为目标函数,而以其面板上第二至第五环筋板的壁厚t2、t3、t4、t5和椭圆形牛腿内孔的半径r为设计变量,在利用ANSYS Workbench软件中的Design Explorer模块对刀盘尺寸进行优化设计后,刀盘强度最弱部位在正常工况下的静强度与名义疲劳寿命均可分别得到进一步的提升。上述研究结果为兰州地铁掘进施工所用某型土压平衡式盾构机刀盘结构的优化设计提供了参考依据。
[Abstract]:In recent years, as the main excavation tool of underground tunnel, shield machine is playing an irreplaceable role in the construction of railway, highway and subway engineering in China. Because the tunneling efficiency of shield machine is greatly affected by its cutter head structure, it is of great significance to analyze and optimize the structure of the cutter head of each type of shield machine. In this paper, the cutter head structure of a kind of earth pressure balance shield machine used in the construction of Lanzhou metro line is taken as the research object, and its static strength, stiffness and fatigue strength under normal working condition, maximum thrust condition and static start-up and relief condition are analyzed. Based on the analysis of mechanical properties such as natural frequency, suggestions for improving and optimizing its structure are put forward. In this paper, the mechanical properties of cutter head structure under normal working condition are analyzed by ANSYS Workbench software. According to the equivalent stress, total deformation and nominal fatigue life of the shield machine, it is determined that the weakest part of static strength and fatigue strength on the cutter head of the shield machine is located at the outer corner of the corbel near the back of the panel. The relatively weak stiffness is located on the outer edge of two uncut slags. Secondly, an improved design scheme is put forward in view of the shortcomings of the current cutter head. By analyzing the structure of the improved cutter head, it is found that when the opening rate of the cutter head changes from 35% to 37%, The static strength and nominal fatigue life of the weakest part of the cutter can be increased by 37% and 221% respectively under normal working conditions, while the deformation at the outer edge of the panel can be reduced by about 15%. Thirdly, on the basis of static analysis, the dynamic analysis of the improved cutter head is carried out, and the vibration pattern of the cutter head, the first six natural frequencies, the frequency of the maximum amplitude and the maximum amplitude are obtained. The calculation shows that the low order natural frequency of the improved cutter head increases from 35.58 Hz to 36.89 Hz from 47.93 mm to 46.05 mm. Finally, the multi-objective optimization method is used to optimize the main dimensions of the cutter head structure. Taking the maximum equivalent stress 蟽 I max, total deformation emax and mass m of the cutter head as the objective function, and taking the thickness of the second to fifth ring stiffened plate on its face as the design variable, and the radius r of the inner hole of the oval leg as the design variable, the maximum equivalent stress 蟽 I max, the total deformation amount emax and the mass m of the cutter head are taken as the design variables. After the design Explorer module of ANSYS Workbench software is used to optimize the size of the cutter head, the static strength and nominal fatigue life of the weakest part of the cutter head under normal working conditions can be further improved. The above results provide a reference for the optimum design of the cutter head structure of a kind of earth pressure balance shield machine used in the construction of Lanzhou Metro tunneling.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.39

【参考文献】