An Analysis of Dynamics of Retaining Wall Supported Embankments: Towards More Sustainable Railway Designs

Abstract

Retaining walls are structures used to retain earth materials on a slope. Typically, they are designed for static loads, but for highway and railway infrastructures, vehicle-induced dynamic responses are also relevant. Therefore, retaining wall structures are often designed with a factor of safety that is higher than necessary, because it can be challenging to quantify the magnitude of expected dynamic stresses during the design stage. This unnecessary increase in material usage reduces the sustainability of the infrastructures. To improve railway retaining wall sustainability, this paper presents the results from a field monitoring campaign on a heavy-haul rail line with a retaining wall, studying the dynamics induced in response to 30-ton axle load trains running at speeds of between 5 km/h and 100 km/h. The site comprises an earth embankment supported by a gravity retaining wall, with accelerometers on the sleepers, roadbed surface, and retaining wall, velocity sensors on the roadbed, and strain gauges on the rail web to record wheel–rail forces. The vibration intensities collected from various locations are processed to explore the peak particle velocities, maximum transient vibration values, and one-third octave band spectrums. Two transfer functions define the vibration transmission characteristics and attenuation of vibration amplitude along the propagation path. The long-term dynamic stability of the track formation is studied using dynamic shear strain derived from the effective velocity. The peaks of observed contact forces and vibrations are statistically analyzed to assess the impact of train speed on the dynamic behavior of the infrastructure system. Next, a 3D numerical model expresses the maximum stress and displacements on the roadbed surface as a function of train speed. The model evaluates the earth pressures at rest and vehicle-induced additional earth pressures and horizontal wall movement. The investigation provides new insights into the behavior of railway track retaining walls under train loading, and the field data are freely available for other researchers to download. The findings could facilitate the design of more sustainable retaining walls in the future.

Long-term supportable development programs for railway systems

“…The railway industry requires strategic investments and Supportable development plans that trigger the subsidy economy of the system and improve commercial competitiveness and technological innovation. (Feng et al, 2023) The scenario of a future railway system shows growth of around 42% with 4% energy consumption in the next three decades. The advantages of the railway industry over all means of transport are to have a confined lane (which is only used by this means of transport), which generates a second advantage: reduction of transfer times, which implies two more advantages, reduction of energy consumption and generation of pollutants.…”

Sustainable Retaining Wall Solution as a Mitigation Strategy on Steep Slopes in Soft Rock Mass

“…The results were presented using a real case of a slope movement where four different types of ERWs were proposed to stabilize the slope. Although several studies on the optimal design of individual earth-retaining walls based on construction costs [7][8][9][10] or life cycle assessments [11][12][13] have already been successfully carried out, none of the research work to date has dealt with the optimal design of several retaining walls that are successively built on top of each other over different periods of time. The provision of such an optimal design leads to the verification of several additional stability failure mechanisms.…”

Dynamic displacement of sheet pile walls adjacent to the railway track

“…A field study was done by Feng et al [9] to investigate the vibration response of the railway track backfill and adjacent retaining wall. The properties of the materials substantially impact the transmission of vibrations to the structures, in contrast to the influence of speed.…”