Experimental study and numerical analysis for vibration isolation performance on H-shaped steel interlocking pile

The propagation of vibration waves through the ground can pose a threat to the stability of adjacent structures and the well-being of the populace. It is evident that periodic structures, utilizing band-gap properties, demonstrate considerable promise in the field of vibration attenuation. The present study proposes a novel periodic vibration isolation structure using H-shaped steel interlocking piles. The model and materials were designed in accordance with similarity criteria, with vibration isolation performance initially verified through model tests and subsequently analyzed and validated via numerical simulations. The isolation mechanism was revealed from an energy distribution perspective. The findings demonstrate that H-shaped steel interlocking piles effectively attenuate vibrations in the following frequency ranges: 50-79 Hz, 97-361 Hz, and 373-400 Hz (prototype: 4-7 Hz, 8-29 Hz, 30-32 Hz). In comparison to side-by-side pile arrangements, the relative bandwidth is enhanced by approximately 16%, and the lower cutoff frequency reduction is increased by around 30%. Within a certain range, isolation improves with longer piles. The spacing of piles has been shown to have a non-monotonic effect, with optimal spacing achieving a balance between diffraction and structural stiffness to maximise performance. Energy analysis indicates that the structure guides vibration energy downward for spatial redistribution, with the mechanism rooted in synergistic multiple-reflection energy dissipation and local-resonance energy absorption. H-shaped steel interlocking piles have been shown to offer superior low-frequency attenuation and broadband characteristics, thus presenting an effective solution for low-frequency vibration control in engineering applications.