Stochastic analysis of dynamic stress amplification factors for slab track foundations

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Abstract
The relationship between railway track-bed stresses and speed is essential when performing track foundation design. Current approaches to describe this relationship are typically empirical and multiply the static track response by a dynamic amplification factor to account for speed effects. This paper develops an alternative method for dynamic amplification factor generation instead of numerical simulation. A vehicle–track dynamics model is presented, capable of simulating the subgrade dynamics considering random track irregularities. First, samples of irregularity are generated based on a mean vertical track profile power spectral density. A range of train speeds and track-spectrum cumulative probabilities are computed using the numerical model before analyzing the resultant surface stresses. The resulting dynamic amplification factors follow a Gumbel distribution. Data normalization is performed before developing a bespoke dynamic amplification function. Based on speed, track-spectrum cumulative probability, and p-values, the proposed model yields dynamic amplification predictions within 5% of the simulated values.
Funding Information
  • Higher Education Discipline Innovation Project (B21011)
  • National Natural Science Foundation of China (52078435)
  • Natural Science Foundation of Sichuan Province (2023NSFSC0391)
  • Key Laboratory of Mechanical Behavior Evolution and Control of Traffic Engineering Structures in Hebei (SZ2022-03)
  • Royal Society (IEC\NSFC\211306)

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