Wyniki wyszukiwania - BazTech

1

A laboratory study of pressure distribution and residual settlements in wide grading double layer railway ballast under long-term cyclic loading

Sysyn M., Gerber U., Nabochenko O., Dehne S.

Archives of Civil Engineering

|

2020

|

Vol. 66, nr 4

561--578

EN

Ballast layer has weighty share in the lifecycle costs of railway track. The strict standards and maintenance rules of ballast grading significantly contribute to the ballast costs. One ways to the costs reduction is differential demands to ballast grading for the secondary and low loaded railway lines. Additional one is the different ballast grading over the ballast height. This study presents a full scale laboratory investigation of technical efficiency of such railway ballast under the long-term cyclic loading in comparison with the standard ballast layer. The double layer is presented with standard grading ballast upper layer and bottom sub ballast layer consists of ballast mixture. Pressure distribution under the ballast layer and permanent settlements of the layers are measured during the loading cycles. The reference measurements with standard grading ballast material are carried out. The study shows that initial settlement accumulation of the double layer railway ballast are lower to that of the standard ballast layer. However, the settlements accumulation intensity of the ballast is higher. The analysis of the pressure distribution measurements under the ballast layer and the settlements inside the ballast layer explain the causes of the different settlement accumulation.

2

The complex phenomenological model for prediction of inhomogeneous deformations of railway ballast layer after tamping works

Sysyn M., Gerber U., Kovalchuk V., Nabochenko O.

Archives of Transport

|

2018

|

Vol. 47, iss. 3

91--107

EN

The given article considers the method of calculating the track geometry deformation with respect to uneven accumulation of residual deformations along the track. The technique proposes two significant changes in existing approaches to calculating the efficiency of the ballast layer. The transition from the approach of allowable stresses design in the ballast layer to the deformative approach of accumulations of track geometry deformations allows us to draw conclusions regarding the intervals of track tamping and the duration of ballast layer life cycle. The transition from the determinative to probabilistic approaches makes it possible to draw conclusions not only from the average unevenness, but also with regard to all possible facts of unevenness. The method is based on the mechanism of sudden and gradual deformations occurrence, which depends on a number of key factors: dynamic stresses on the ballast, non-uniformity of track elasticity, performance of current maintenance work. Based on the experimental studies results, the dependencies of sudden deformations and the intensity of gradual deformations on the level of stress on the ballast layer were established. The experimental results of the influence of the subballast base elasticity on the intensity of accumulation of residual deformations are shown. On the basis of the developed method, the prediction of track geometry deterioration for a given structure of the track, the rolling stock and the permissible level of geometric deviations for track maintenance is presented.

3

Vehicle-based assessment of frog wear. Modern measuring systems allow new inspection concepts

Gerber U., Zoll A., Fengler W.

Przegląd Komunikacyjny

|

2015

|

Nr 7

26--27

EN

In the paper a model of vehicle wheel contact with wing rail and frog has been described. Influence of speed on dynamic forces has been noticed. It has been stated that modern measuring systems may facilitate inspection and maintenance strategies.

XX

W artykule opisano model współpracy koła kolejowego z szyną skrzydłową i dziobem krzyżownicy. Opisano wpływ prędkości na oddziaływania dynamiczne. Podkreślono korzyści płynące z nowych możliwości pomiarowych na strategię prowadzenia prac utrzymaniowych.