Assessment of Ground-Borne Vibration from Underground Trains on a Proposed Residential Development

Underground railway traffic can cause significant vibration and noise levels in buildings or structures at the surface. Good construction practice requires the estimation of vibration levels in proposed buildings of sensitive use. This paper presents the prediction and assessment of ground-borne vibration in a residential development proposed above the Piccadilly Line in London. A prediction software (PiP) developed at Cambridge University was used to determine differentials between vibration at the surface and vibration at the bottom of pile foundations. The software incorporates the effects of boundaries on wave propagation and provides useful comparisons between two locations. The differentials were applied to measurements taken at ground level to estimate the level of vibration that would excite the piles. Appropriate building transfer functions were used to predict the propagation of energy into the piles and up through the building structure. The levels of predicted tactile vibration and structure-borne noise were compared to criteria for the assessment of human response and building damage. The results showed that vibration within residential room spaces will be large enough to cause adverse human response but not large enough to cause building damage. Uncertainty in the accuracy of results has been shown to originate from assumptions made of the soil loss factor, highlighting the need for detailed examination into soil loss factors at sites where new buildings with piled foundations are proposed above, or proximate to, underground railway lines. Mitigation solutions to isolate the upper structure of the building from the piled foundations have been proposed.