Vibration characteristics and isolation of a high-speed railway bridge under low-frequency ground-borne environmental vibrations

Most research focuses on railway-induced vibrations, leaving the threat of environmental vibrations to railway operational safety largely unexplored. This study addresses severe resonance in a nearby high-speed railway (HSR) bridge caused by low-frequency industrial machinery vibrations. Field measurements and numerical simulations were integrated to analyze the vibration transmission mechanism and the effectiveness of pile row isolation. Field tests revealed that ground motions induced lateral pier bending and girder translation at a 1.5 Hz resonance frequency, resulting in a dangerous lateral amplitude of 1.33 mm. Numerical simulations indicated that while lateral ground vibrations can be blocked by pile rows, bridge vibrations may be counter-intuitively amplified by an improper design (e.g., a single row) under specific operational conditions. Parametric analysis established that geometric parameters govern effectiveness: pile spacing should be reduced and pile length must exceed 0.5 times the vibration wavelength. Material improvements beyond a wave impedance ratio of 10 showed negligible benefits. An optimized design finally reduced the lateral amplitude to 0.298 mm, satisfying the 0.3 mm limit. This work provides vital reference for HSR planning in industrial zones.