Vibrationer fra togtrafik: Femern Bælt-forbindelse
Translated title
Vibrations from railway traffic: The Femern Belt Link
Author
Kiel, Nikolaj
Term
4. term
Education
Publication year
2011
Submitted on
2011-06-09
Pages
96
Abstract
Denne afhandling undersøger vibrationer fra tog på den planlagte jernbane på den danske side af Femern Bælt-forbindelsen. Fokus er på, hvordan vibrationer bevæger sig gennem jorden og ind i en referencebygning 25 m fra sporet. Bølgeamplituder vurderes for to jordprofiler og for to bygningskonfigurationer med forskellige randbetingelser. Analysen tager højde for afstanden til kilden og frekvensen af togbelastningen, med særlig vægt på transmissionen af jordbårne bølger ind i bygningen. Responsen beregnes med både en ukoblet model—hvor jord og struktur analyseres hver for sig—baseret på randelementmetoden (Boundary Element Method, BEM) og finit element-metoden (Finite Element Method, FEM), samt en koblet model, der kombinerer BEM og FEM og inddrager jord-struktur-interaktion. Resultaterne viser, at tæt på bygningens naturlige frekvenser (dens foretrukne svingningsrater) påvirker bygningens dynamik jordens respons markant. Ved strukturens egensfrekvens kan reaktionskræfter fra bygningen i den koblede model opveje jordens bevægelse og føre til reduktioner i jordresponsen på op til 80 %.
This thesis examines vibrations from trains on the planned railway on the Danish side of the Femern Belt Link. It focuses on how vibrations travel through the ground and into a reference building located 25 m from the track. Wave amplitudes are evaluated for two soil profiles and for two structural configurations with different boundary conditions. The analysis accounts for distance from the source and the frequency of the train loading, with particular attention to the transmission of ground-borne waves into the building. Responses are computed using both an uncoupled model—where soil and structure are analyzed separately—based on the Boundary Element Method (BEM) and the Finite Element Method (FEM), and a coupled model that combines BEM and FEM to include soil–structure interaction. The results show that near the building’s natural frequencies (its preferred vibration rates), the building’s dynamics strongly influence the soil response. At the structure’s eigenfrequency, reaction forces from the building in the coupled model can balance the soil motion, leading to reductions in soil response of up to 80%.
[This abstract was generated with the help of AI]
Keywords
vibrations ; finite ; element ; boundary ; femern ; belt ; elastodynamic ; wave ; transmission ; soil ; structure ; interaction