Determination of the characteristics of local instabilities, taking intoaccount their causes and loads

子项目EPIB 1.1的目的是确定现有常规道碴轨道上现场不稳定性的原因，该子项目标题为确定局部不稳定性的特征，同时考虑其原因和荷载。局部不稳定性的特征将通过评估在选定的轨道部分上测量的数据来确定;主要是由于轨道在垂直方向上受到交通荷载的相对位移而产生的振幅和波长。所产生的知识将用于分析计算交通负荷（准静态和动态力），这是由局部不稳定性引起的，会影响现有轨道。主要目标是通过评估轴承加速度来早期检测局部不稳定性。通过现场测量（EPIB 2）的平衡状态下的道床和出现的局部不稳定性，首先一个典型的模式，局部不稳定性将开发基于轮轨力。车轴轴承加速度也将由相同的轮轨力决定。最后，将发展一种基于局部不稳定性特征的算法。该算法可以通过轴承加速度系统地、早期地检测出局部失稳。考虑到子项目EPIB 1.1中获得的知识，合作项目的目标包括确定局部不稳定性的原因，以及考虑现有运营计划确定轨道质量恶化的进一步过程的粗略预测。子项目EPIB 1.1是主项目的一部分，该主项目被称为通过下部结构/底土中的细粒土对传统有碴轨道的现有道床的局部不稳定性进行早期检测。从分项目EPIB 1.1中获得的结果作为制定另外两个分项目EPIB 1.2和2 EPIB的基础。此外，EPIB 1.1通过实现主要目标，即利用轴承加速度对局部不稳定性进行早期无损检测，为联合项目的总体目标做出了贡献。

The purpose of subproject EPIB 1.1, entitled Determination of the characteristics of local instabilities, taking into account their causes and loads, is to determine the causes of locale instabilities on existing conventional ballast tracks. The characteristics of local instabilities will be determined by evaluating the data measured on selected track-sections; primarily the amplitude and wavelength resulting from the relative displacement of the track subjected to traffic loads in the vertical direction. The knowledge generated will be used for the analytical calculation of the traffic load, (quasi static and dynamic forces), which results from a local instability and that affects the existing track. The main goal is the early detection of local instabilities by evaluating the axle bearing acceleration. Through in-situ measurements (EPIB 2) on a track bed in equilibrium and for arising local instabilities, first a typical pattern for local instabilities will be developed based on wheel-rail forces. The axle bearing acceleration will also be determined by the same wheel-rail forces. Finally, an algorithm based on the characteristic of local instabilities will be developed. With this algorithm local instabilities can be detected systematically and at an early stage by axle bearing acceleration. Taking into consideration the knowledge acquired in subproject EPIB 1.1, the goal of the collaborative project includes the determination of the causes of local instabilities as well as the determination of a rough prognosis of the further process of track quality deterioration in consideration of an existing operating program. Subproject EPIB 1.1 is part of the main project known as Early detection of local instabilities on existing track beds for conventional ballast tracks by fine-grained soils in substructure/subsoil. The results obtained from subproject EPIB 1.1 serve as the basis for the development of two more sub-projects EPIB 1.2 and 2 EPIB. Moreover, EPIB 1.1 contributes to the overall objective of the joint project by achieving the main objective, which is the early non-destructive detection of local instabilities using axle bearing acceleration.