【作者】 徐光辉；

【导师】 蔡英；

【作者基本信息】 西南交通大学 ， 道路与铁道工程， 2005， 博士

【摘要】 路基是一种三维带状结构物,是道路和铁道的基础设施,具有非常重要的作用。路基结构的性能及其优劣是在修筑的全过程(成型过程)中形成的,取决于路基的结构形式、填料和压实质量。本文以系统科学思想为指导、以弹塑性动力学理论和现代动态测试技术为基础,对路基结构在形成过程中的连续动态监控问题做了系统的研究,初步形成了一套以振动压路机为激励源的实时的、连续的动态监控技术,并已在工程上进行了较为成功的应用,特别是在粗粒土路基的压实控制方面。 常规的压实质量控制方法以非连续测试为主,且大部分不适合粗粒土压实问题。在对现有的路基压实质量控制方法进行的总结和分析的基础上,重点剖析了国外的压实计方法。这是一种基于振动压路机的连续压实控制方法,从1978年起,经过不断完善,已经在欧美地区得到了广泛的应用。可以对压实区域实现快速、全面的压实质量控制,这是常规方法无法做到的。该方法通过谐波比的评价指标来评价压实质量,但是理论研究和实际验证都表明,该指标具有一定的局限性,很难适合粗粒土的压实评价。因此建立适用范围更广的连续控制方法便成为本文的核心问题。 首先,按照系统科学理论建立了路基结构系统的基本概念。路基系统的性能受组成要素——颗粒以及颗粒之间的关联方式的制约。而粗粒土路基系统的状态可由其密度、模量和抗剪强度指标来表征,系统状态的变化在宏观上可以用其结构抗力的变化来表达。根据弹塑性力学和系统理论,分析了路基系统在形成过程中的演化规律,探讨了路基结构的塑性变形与其抗力之间的定性关系,为正确判别压实过程中路基系统的压实状态打下了基础。 其次,分析和讨论了压实机具与被压材料之间的相互作用问题。给出了路基在周期荷载作用下表面垂向的位移理论解答,并着重对振动压路机的响应进行了数值仿真分析,指出了压实作用力与激振力的区别与联系。在此基础上建立了压实机具在压实过程中的动力学模型,按照线性与非线性两种情况对方程进行求解和分析。指出系统抗力与其加速度之间为线性关系,因此定义了抗力指标——加速度,其目的在于方便实时量测和快速监控。在理论研究的基础上,研究了压实过程的测试技术,介绍了自行研制的压实过程监控系统的组成、特点和信号处理方法。根据控制理论,给出了压实质量控制的原理、内容和实施的方法,为实际的工程应用奠定了基础。更多还原

【Abstract】 The subgrade is a kind of three-dimensional belt-shaped structure, it is the infrastructure of road and railway, and has very important function. The performance of subgrade structure is formed in the course of its shaping process, it is determined by selecting the fine filling and plenty compaction. This article takes the thoughts of system science as the instruction, and the elastic-plastic dynamic theory and modern dynamic testing technology as basis, made a research on the problem of continuous dynamic monitoring in the forming process of subgrade structure, and initially formed a set of real-time, continual dynamic monitoring technology, which take the vibration roller as its driving source, and carried on a quite successful application, especially in compacting controlling about coarse grain.The method of conventional compaction quality control primarily bases on the non-continual testing, and most part of which doesn’t fit for the problem of coarse grain compaction. On the basis of the generalization and analyze on existing controlling method of subgrade compaction quality, it emphasis on analyzing the overseas compactor method, which is a kind of continue compaction control method based on vibration roller, it has got the extensive application in the Euro-American region, after pass by continuously perfect since 1978. It can realizes quantity control completely and rapid, and this is impossible that the normal method do it. The method appraises the compacting quality through the evaluating index of harmonic ratio. However, both the theoretical and practical researches show that this method has certain limitations, and it’s difficult for compacting appraisal of coarse grain. So establishing the continue control method that is suitable for a more broad range is to become the core of this article.Firstly, according to the system science theory, established a general concept of subgrade structure system. The performance of subgrade system is restricted by its consisting factors—grain and the connecting way of them. But the state of coarse grain subgrade system is expressed by the indexes of its density, module and shearing strength. The change of system state can be represented by its change of structure resistance on macroscopic view. According to elastic-plastic meachnics and system theory, analyzed the evolvement principles of which the subgrade system on its forming process, and discussed the qualitative relations between the plasticdeformation and the resistance of the subgrade structure, laid a foundation for accurately estimating the subgrade system’s compacting state in its compacting process.Secondly, analyzed and discussed the interacting problems between the compaction machine and compacted materials. It gives a vertical displacement solution on theory under the periodic load, and emphatically conducted the value simulated analysis to the vibration roller’s response, indicated the distinction and relation between the compacting force and exciting force. On the basis of which established the dynamic model of compacting machine in the compacting process, under the linear and non-linear conditions, made the solution and analysis to the equation. Pointed out the relation between system resistance and its acceleration is linear, therefore defined the resistance index—acceleration, its goal is for the convenience of real-time measuring and fast monitoring. On the basis of theoretical research, studied the testing technology of the compacting process, introduced the composition, characteristics and the signal processing method of compaction process monitoring system which independently developed. According to control theory, produced the principle, content and implementing method of compaction quality control, and laid foundations for practical project application.Finally, made researches on the monitoring technology’s applied problem in the stone ballast subgrade compacting process. To guarantee vibration roller conducting its compacting tasks on rated parameters is the precondition to use it as driving force to conduct compacting quality testing and controlling. Therefore, made the real-time supervision on the key parameters—excited frequency which can affect the compacting craft, the control method is throttling. Through changing the size of throttling, to realize the working frequency is near the rated value. On the basis of which analyzed the quality monitoring problem of the degree of stone ballast subgrade compaction and its uniformity. To the degree of compaction, should comprehensively apply standardization and relative method to implement the quality supervision, that is to distinguish the change and stability of subgrade plastic deformation by the dynamic responsive signal changes of vibrating wheel in the course of neighboring two times compaction, according to this determined whether finished compacting work on this kind of craft;Through the standardization distinguished whether achieved existing request, whether need to change the craft tocontinue the compaction. The applied example showed the change of compacting craft and the improvement of padding attribute is extremely effective for increaseing the compacting degree and the stability. The compacting uniformity is an extremely complex question, what kind of variation level by controlling involves to the influencing question of the subgrade structure’s long-term service performance.This article used mathematical statistic principle for controlling, separately carried on the discussion from the point of view of the distribution of the whole variability and the partial non-uniformity, analyzed the padding changeability is the primary factor which affect the subgrade uniformity. Changing padding attribute and the compacting craft really can reduce the changeability. By conducting the contrast analysis between the dynamic measuring compacting data and the result of correspondingly conventional experiment such as deflection and the module, confirmed that the relation between them is one kind of direct-way relations, ulteriorly explained the feasibility of using the dynamic method.The monitoring technology established by the dynamic concept and the method in this article is feasible which proved by practice, it is helpful for the improvement of the whole roadbed construction level, and has the good application prospect and the high extension value.更多还原