A Sustainable Vibration Isolation Technique Using Half-Filled Trenches with Sand–Crumb Rubber Mixture: A Finite Element Analysis Study

Ground vibrations induced by traffic and industrial activities can adversely affect human comfort and nearby sensitive equipment. Wave barriers, particularly open trenches (OTs), are recognized as effective vibration isolation solutions; however, their practical implementation may be limited by the difficulties associated with maintaining a fully OT. While trench infilling and sand crumb rubber mixture (SCRM) materials have been investigated separately, a continuous, non-alternating, partially SCRM-filled trench configuration has not yet been systematically evaluated through detailed numerical analysis for single and multiple trench arrangements. PLAXIS 2D was used to compare open, fully SCRM-filled, and partially SCRM-filled trenches at filling ratios of 25%, 50% and 75%, with the lower portion filled and the upper portion, within the near-surface zone of highest Rayleigh wave energy concentration, left open. Although the OT provided the highest isolation efficiency, followed by the 25% filling configuration, the 50% SCRM-filled configuration (SCRMT) emerged as a more practical alternative, achieving a barrier efficiency close to that of the OT (70% versus 75%, under identical conditions) while reducing the required unsupported open-trench depth by half and diverting waste tire material from landfills. The influence of trench depth, width, source-to-trench distance, and multiple-trench arrangement on SCRMT performance was also examined.