Application of Quarter Car Model for Assessment of Attenuation Characteristics of Soil at Low Strain
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Application of Quarter Car Model for Assessment of Attenuation Characteristics of Soil at Low Strain P. S. Rao 1 & A. K. Desai 1 & C. H. Solanki 1 Accepted: 6 September 2020/ # Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Due to increase in population, industrialisation and a lack of space in the urban areas of Surat city in Gujarat (India), numerous buildings are being constructed in the vicinity of the railway tracks. The perspective is further aggravated by the proposal for a high-speed corridor (≥ 200 kmph) connecting two key Indian cities, Mumbai and Ahmedabad. These structures need to be evaluated for their susceptibility to the dynamic stresses induced by such high-speed locomotives. However, before the assessment of such dynamic stresses, geometrical and material damping properties of the in situ soil must be determined as the stresses induced in the structure also depend on the attenuation characteristics of the subsoil. With the objective to determine attenuation characteristics of the soil due to high-speed trains, the current study uses modelling capabilities of SAP2000 to prepare a vehicle-tracksoil interaction model for dynamic analysis of the site in Surat city (India). A quarter car model (lumped mass model) prepared in SAP2000 environment is used to replicate CHR3type high-speed train. The passage of train over the track structure is represented as a sinusoidal harmonic load. The study establishes that the statistical analysis of the attenuation of the waves is exponentially related to the distance from the source and follows the Bornitz equation. The frequency-independent damping ratio is computed considering near-field and far-field effect of induced vibration in the soil. Finally, the damping ratio and transmissibility are used to derive the critical velocity for the given track near the proposed site. Keywords Dynamic amplification . Geometrical damping properties . Material damping
properties . Harmonic loading . Quarter car model . Attenuation . Critical velocity * P. S. Rao [email protected] A. K. Desai [email protected] C. H. Solanki [email protected]
1
Civil Engineering Department, Sardar Vallabhbhai Patel National Institute of Technology, Surat, Gujarat, India
Transportation Infrastructure Geotechnology
1 Introduction With an advent of high-speed corridors, the environmental vibration induced by running trains has been given more attention. The vibration propagates from the track into the subsoil causing the ground vibration. This further arouse secondary vibration and noise of nearby structures and buildings, which seriously influences the living and working environment of the people. The level of train-induced ground vibrations depends on various factors including the wave propagation at a site based on type of soil. Studies have shown that very strong vibrations are induced when the train is at a speed close to the velocity of Rayleigh wave in soil. Krylov (1995) predicted that, if the velocity of train exceeds Rayleigh wave velocity in t
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