الفهرس 
Prediction of vibrating behavior of ballast layer.
METHODOLOGY STATEMENTOnly 14 pages are availabe for public view
 |  | from | 187 |  |  |
| | | from | 187 | | |
Abstract
According to decrease the life time span of the railway track elements compared to the designed life time span, it must be to search for reasons that lead to this problem.
One of the important reasons is the settlement that may happened in the soil existed beneath the track (subgrade layer). This settlement is due to many reasons such as; excavation works, failure of the retaining walls of the track, change in the ground water level or settlement in the civil works under the track as pipes, box culverts, tunnels, vault or etc.
The following methodology was applied:
1- Studying the previous researches related to the thesis topics.
2- Determining the effective and affected factors concerning to the settlement happened in subgrade layer.
3- Using finite element software program (ANSYS) to analyze some cases study due to settlement of subgrade soil.
4- Obtaining the conclusions and recommendations.
The railway track is modeled by FEM using software program ANSYS Workbench V.14.0.
The aim of modeling the railway track is to know how much percent of increasing stresses in railway track elements as a settlement happened beneath the subgrade layer in different cases of contact between elements. It has been made three cases of modeling the track. Each case has seven models of the railway track:
The first case studied the ideal state of the track without any defects and another with defect state that has settlement starting from 5mm and increase it gradually to end to 10mm. Bonded contact between sleepers and ballast also between rail and rail pads are investigated.
The second case studied the ideal state of the track without any defects and another with defect state that has settlement starting from 5mm and increases it gradually to end to 10 mm. Frictional contacts between sleepers and ballast also between rail and rail pads are investigated.
The third case studied the ideal state of the track without any defects and another with defect state that has settlement starting from 5mm and increases it gradually to end to 10mm. Frictional contact is between sleepers and ballast moreover bonded contact is between rail and rail pads.
Finally by analyzing the results, it can be derived a public equation refer to the percentage values of increasing stresses in each element of the modeled track for a vertical settlement in subgrade soil with constant parameters. Recommendations and further studies are proposed after getting results.