Stochastic analysis of dynamic stress amplification factors for slab track foundations

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.

KEYWORDS:

• Railway slab track
• track-bed stress
• vehicle–track coupled dynamics
• track irregularity
• Stochastic analysis, dynamic amplification factor

Acknowledgments

The study was supported by the National Natural Science Foundation of China (52078435), the Natural Science Foundation of Sichuan Province (2023NSFSC0391), the Royal Society (IEC\NSFC211306 – International Exchanges 2021 Cost Share), the Key Laboratory of Mechanical Behavior Evolution and Control of Traffic Engineering Structures in Hebei (SZ2022-03), and the 111 Project (B21011).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the 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].