【作者】 周陶勇；

【导师】 胡斌；

【作者基本信息】 昆明理工大学 ， 机械设计及理论， 2017， 博士

【摘要】 捣固作业是有砟铁路养护维修的重要组成部分,对提高道床的密实度、增加轨道的稳定性、保证列车的运行安全等都有着重要的作用。随着铁路运输向高速方向发展,在高速动荷载作用下,铁路轨道承受的振动和冲击更加明显,对铁路轨道的要求更加严格,对捣固作业的要求更加精准。由于有砟道床是由级配碎石组成的散粒体结构,在捣固作业过程中具有非线性响应和自组织行为等复杂力学特性,给捣固作业力学机理的研究带来了一定的困难,捣固参数的选取通常还要依靠实践经验和现场试验,缺乏相应的理论依据。因此,深入系统地研究捣固作业过程中道床的力学行为及其变化规律以及捣固参数对捣固效果的影响,不仅对捣固作业力学机理的研究有着重要的理论意义,而且对精准选取捣固参数、有效提高捣固效果有着重要的实用价值。为了研究捣固作业力学机理,精准选取捣固参数,有效提高捣固效果,本文首先从理论上分析捣固作业的密实机理和捣固参数对捣固效果的影响;接着分别运用物理试验和数值模拟的方法,对捣固作业过程中道床的力学行为及其变化规律进行测试和分析,从细观尺度上对捣固作业的力学特性进行研究;然后运用响应面方法构建捣固作业的响应面模型,进行捣固参数的优化分析,并运用组合预测方法创建捣固参数的预测模型,为精准地选取捣固参数奠定基础;最后通过引入参数自适应机制,提出一种变值捣固参数,从而更好地提高捣固效果,为捣固参数的选取和优化提供一种新的研究思路。具体的研究内容如下:1.基于振动密实理论,在分析有砟铁路捣固作业工作原理的基础上,提出了捣固作业的力学模型,从理论上研究捣固作业的密实机理和捣固参数对捣固效果的影响,并推导了捣固参数与道床状态参数之间的函数关系,为捣固参数的精准选择提供理论依据。2.基于灌水法和传感器测试技术,对捣固作业前后的道床密实度和道床支承刚度以及捣固作业过程中道砟加速度和轨枕底部压力等道床的力学行为及其变化规律进行了测试和分析。根据捣固作业物理试验研究的需要,构建了 1:1全尺寸捣固试验装置;在小道砟箱中对捣固作业前后的道床支承刚度和道床密实度进行了测试,分析了捣固参数对捣固作业后道床支承刚度和道床密实度的影响,探讨了道床支承刚度与道床密实度之间的关系;在大道咋箱中对捣固作业过程中道砟加速度和轨枕底部压力进行了测试,分析了捣固作业过程中道砟加速度和轨枕底部压力的变化规律,提出了道砟加速度和轨枕底部压力产生变化的主要因素。3.基于颗粒物质力学理论和离散元分析方法,对捣固作业过程中道床的力学行为及其变化规律从细观尺度上进行了模拟和分析。运用离散元分析方法,创建了捣固作业的离散元仿真分析模型,其中该模型的细观力学参数是在物理试验的基础上通过反演法进行标定;运用该模型进行捣固作业仿真分析,分别提取轨枕下方的道床密实度、道砟加速度和轨枕受力状况,并与物理试验的测试结果进行比较,通过对比发现仿真结果与物理试验结果基本吻合,说明捣固作业的离散元分析模型是有效的;再分别提取捣固区域内道砟配位数和道砟颗粒之间接触力链的演变历程,进一步从细观尺度上描述捣固作业过程中道床的力学行为及其变化规律。4.基于响应面理论、组合预测方法和参数自适应机制,对捣固参数的优化和预测进行了研究。运用响应面理论,构建了体现捣固参数与捣固效果之间关系的响应面模型,并对捣固参数进行多因素多目标的优化分析;通过对不同初始状态的有砟铁路进行捣固参数的优化分析,提出一种基于相关程度的组合预测方法,创建了捣固参数的预测模型;通过引入参数自适应机制,提出一种变值捣固参数,并分别进行仿真试验研究和物理试验研究。研究表明,在捣固作业过程中,变值捣固参数的捣固效果比定值捣固参数的捣固效果要好,说明变值捣固参数比定值捣固参数更加合理。本文结合振动密实理论、试验测试技术、离散元分析方法和参数优化理论,对有砟铁路捣固作业过程中道床的力学行为及其变化规律和捣固参数对捣固效果的影响进行了系统地分析,为高速有砟铁路的精准捣固提供参考。更多还原

【Abstract】 The tamping operation is an important component of ballast railway maintenance,which plays an important role in improving ballast compactness,increasing track stability and ensuring safety operation of train.With the development of high speed railway,under the action of high speed dynamic load,the vibration and impact of railway track is more obvious,the requirement of railway track is more stringent,and the requirement of tamping operation is more accurate.Because the ballast is a particle structure which is composed of graded crushed stone,with non-linear response and self-organized behavior and other complex mechanical properties during tamping process,which has brought some difficulties to research the mechanics mechanism of tamping operation,the selection of tamping parameters usually depends on practical experience and field test,and lacks corresponding theoretical basis.Therefore,the mechanical behavior of ballast and its changing law and the influence of tamping parameters on tamping effect during tamping process were studied in depth,which has great theoretical significance to study the mechanics mechanism of tamping,and great practical value to accurately select tamping parameters and effectively improve tamping effect.In order to study the mechanics mechanism of tamping,accurately select tamping parameters and effectively improve tamping effect,firstly,the compact mechanism of tamping operation and the influence of tamping parameters on tamping effect were analyzed theoretically.Then,the mechanical behavior of ballast and its changing law during tamping process were tested and analyzed by physical test and numerical simulation respectively,and the mechanical properties of tamping operation were studied from the mesoscopic scale.Then,the response surface method was used to construct the response surface of tamping operation,the model was used to optimize tamping parameters,and the prediction model of tamping parameters was established by using the combination prediction method,which laid the foundation for accurately selecting tamping parameters.Finally,by introducing the parameter adaptive mechanism,a variable tamping parameter was proposed to improve the effect of tamping operation,which provides a new research idea for the selection and optimization of tamping parameters.The specific research contents are as follows:1.Based on vibration compaction theory,the working principle of tamping operation on ballast railway was analyzed,and the mechanical model of tamping operation was proposed.The compact mechanism of tamping operation and the influence of tamping parameters on tamping effect were analyzed theoretically.The function relation between tamping parameters and ballast state parameters was deduced,which provides the theoretical basis for the precise selection of tamping parameters.2.Based on irrigation method and sensor test technology,ballast compactness and ballast support stiffness before and after tamping operation and mechanical behavior of ballast and its change law during tamping process,such as ballast acceleration and bottom pressure of sleeper,were tested and analyzed.According to the needs of physical test of tamping operation,the 1:1 full-size tamping test device was created.Ballast support stiffness and ballast compactness before and after tamping operation were tested in the small ballast box.The influence of tamping parameters on ballast support stiffness and ballast compactness after tamping operation is analyzed.The relationship between ballast support stiffness and ballast compactness was discussed.In the big ballast box,ballast acceleration and bottom pressure of sleeper during tamping process were tested.The change law of ballast acceleration and bottom pressure of sleeper during tamping process were analyzed,and the main factors that make the change of ballast acceleration and bottom pressure of sleeper during tamping process were presented.3.Based on granular material mechanics theory and discrete element method,the mechanical behavior of ballast and its changing law during tamping process were simulated and analyzed from the mesoscopic scale.Using the discrete element analysis method,the discrete element analysis model of ballast under tamping operation was established,and the meso-mechanical parameters of the model were calibrated by the inversion method on the basis of physical test.Using the model to simulate tamping operation,ballast compactness,ballast acceleration and sleeper force condition were extracted respectively during tamping process.By comparing the simulation results with the physical test results,it is found that they are basically consistent,which shows that the discrete element analysis model of ballast under tamping operation is effective.The evolution of ballast coordination number and contact force chain during ballast was extracted respectively.The mechanical behavior of ballast and its changing law during tamping process were further described from the mesoscopic scale.4.Based on response surface theory,combination prediction method and parameter adaptive mechanism,the optimization and prediction of tamping parameters were studied.Using response surface model,the response surface model which reflects the relationship between tamping parameters and tamping effects was created.The multi-factor and multi-objective optimization analysis of tamping parameters was carried out.The optimization analysis of tamping parameters of ballast railway with different initial states was carried out.A combination prediction method based on correlation degree was proposed to create a prediction model of tamping parameters.By introducing parameter adaptive mechanism,a variable tamping parameter was proposed,and the corresponding simulation experiment and physical experiment were carried out.The research shows that the effect of tamping operation with variable tamping parameters is better than that with constant tamping parameters,which indicates that variable tamping parameters is more reasonable than constant tamping parameters.Based on vibration compaction theory,test technology,discrete element analysis method and parameter optimization theory,the mechanical behavior of ballast and its changing law during tamping process and the effect of tamping parameters on tamping effect were analyzed systematically,which provides reference for precision tamping of high speed ballast railway.更多还原