A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Interpretation of Railway Track Alignment Measurements in a Geodynamic Perspective
The development in society means that infrastructure like ballasted railway systems are facing challenges due to request for increased number of high-speed trains and heavier freight trains. This implies that ballasted railways get an increased impact from larger dynamic loads. The question is how the ballasted railways are today affected by dynamic loading and how will an increase in train speed and weight change the soil behaviour within the railway embankment. A method of investigating dynamic soil behaviour is via geophysical measurements. Accelerometers are commonly used for vibration measurements and by installing them on trains are measurements possible to perform for complete railway sections. The knowledge of expected natural frequencies for various track components and soil layers are essential when considering frequency based analysis of vibration measurements. Thus, a frequency based analysis of accelerometer measurements from track recording coaches enables a possible method for analysing the impact of dynamic loads on underlying soil materials with means of a knowledge of expected natural frequencies for various track components and soil layers. Importance to study frequency content of ground motions became more relevant after the Mexico City earthquake 1985 i.e. studies on this specific earthquake revealed amplification of ground motions due to a long duration of shaking and resonance of soil deposits and furthermore causing damage to buildings whose natural period was the same as the period of ground motion. Thus, if we consider a railway with long train sets running along the railway line. Long durations of shaking of the ground can occur as well as a possible resonance of various soil layers leading to changes in material properties. An interesting finding regarding vibration measurements conducted on a track recording coach show that after Fast Fourier Transformation of the measured vibration data, a frequency spectrum analysis indicate possibilities to detect resonance of the ballast layer in ...
Interpretation of Railway Track Alignment Measurements in a Geodynamic Perspective
The development in society means that infrastructure like ballasted railway systems are facing challenges due to request for increased number of high-speed trains and heavier freight trains. This implies that ballasted railways get an increased impact from larger dynamic loads. The question is how the ballasted railways are today affected by dynamic loading and how will an increase in train speed and weight change the soil behaviour within the railway embankment. A method of investigating dynamic soil behaviour is via geophysical measurements. Accelerometers are commonly used for vibration measurements and by installing them on trains are measurements possible to perform for complete railway sections. The knowledge of expected natural frequencies for various track components and soil layers are essential when considering frequency based analysis of vibration measurements. Thus, a frequency based analysis of accelerometer measurements from track recording coaches enables a possible method for analysing the impact of dynamic loads on underlying soil materials with means of a knowledge of expected natural frequencies for various track components and soil layers. Importance to study frequency content of ground motions became more relevant after the Mexico City earthquake 1985 i.e. studies on this specific earthquake revealed amplification of ground motions due to a long duration of shaking and resonance of soil deposits and furthermore causing damage to buildings whose natural period was the same as the period of ground motion. Thus, if we consider a railway with long train sets running along the railway line. Long durations of shaking of the ground can occur as well as a possible resonance of various soil layers leading to changes in material properties. An interesting finding regarding vibration measurements conducted on a track recording coach show that after Fast Fourier Transformation of the measured vibration data, a frequency spectrum analysis indicate possibilities to detect resonance of the ballast layer in ...
Interpretation of Railway Track Alignment Measurements in a Geodynamic Perspective
Majala, Jonas (author)
2021-01-01
Licentiate thesis / Luleå University of Technology, 1402-1757
Theses
Electronic Resource
English
Geodynamic Challenges in High Speed Railway Projects
| ASCE | 2004
Geodynamic Challenges in High Speed Railway Projects
| British Library Conference Proceedings | 2004