Environmental Effects of Static Drill-Rooted Energy Piles in Coastal Soft Soil Areas

The static drill-rooted energy pile is an emerging green technology increasingly applied in coastal soft soil areas. Existing research has mainly focused on its heat transfer and bearing characteristics, while studies on its environmental impacts remain limited. Based on the Green Building Evaluation Standard and the Life Cycle Assessment method and drawing on practical energy pile projects in coastal areas, this study developed an environmental impact assessment system for energy piles. A comprehensive evaluation method was established, incorporating four indicators: muck and slurry discharge, vibration, noise, and carbon reduction benefits. Using a pilot project, field testing and theoretical analysis were conducted to assess the environmental impact of static drill-rooted energy piles. The results revealed that muck and slurry discharge is significantly lower compared to bored energy piles. Vibration levels at a site office located 30 m from the construction point were below the annoyance threshold of 0.05 g in terms of relative vibration acceleration. Noise levels dropped below the emission limit of 85 dB at a distance of 5 m. Carbon emissions during the material production stage were reduced by 22–45% compared to bored energy piles and by 12% during the construction stage. During the operation stage, compared to air-source heat pumps, electricity savings of 0.691–0.836 kWh per hour and CO2 emission reductions of 0.471–0.57 kg per hour were achieved. Based on the comprehensive scoring of all indicators, the static drill-rooted energy pile technology received an overall rating of ‘‘excellent.’’ This study provided an evaluation framework for the environmental assessment of energy piles and contributed positively to promoting the development of green infrastructure.