STATE OF THE PRACTICE IN FLORIDA ON DEEP FOUNDATION INSTALLATION-INDUCED GROUND DEFORMATIONS AND VIBRATIONS-Paper

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The study examines Florida geotechnical engineers’ experience with ground deformation and vibration caused by driven deep foundations. A web-based survey of 44 consultants explored reported effects, vulnerable soil conditions, contributing factors, and monitoring and design practices.<br /><br />Most respondents had encountered pile-driving-related ground deformation and damage to nearby structures. Reported effects generally occurred within 50 ft (15 m) of the pile, with settlement typically under 1 in (25.4 mm), although severity varied by site. Loose-to-medium-density sands were considered most susceptible, including sandy profiles with intermittent clay layers over limestone. Heave was also reported where Miami Limestone was shallow.<br /><br />Practitioners identified pile-driving impact characteristics—including transmitted energy, force, and frequency—as important factors in deformation. Soil consolidation associated with dissipation of excess pore-water pressure was another commonly cited cause. Prestressed concrete and pipe piles, both displacement piles, were frequently associated with larger deformations.<br /><br />Monitoring was widely viewed as important: 91% of respondents supported measuring vibration at multiple locations, and most favored monitoring during pile driving and for some time afterward. About half said the farthest sensor should be more than 40 ft (12.2 m) from the pile. Respondents also emphasized planning monitoring during foundation design and tailoring programs to site conditions and nearby sensitive structures.<br /><br />The findings reflect practitioner experience rather than direct measurement of a single project. They nevertheless highlight the need to account for soil conditions, pile and hammer characteristics, and nearby infrastructure when planning driven-pile installations, and to use appropriate vibration and deformation monitoring.

Keywords

geotechnical engineering

pile driving

ground deformation

vibration monitoring

driven deep foundations

Florida soils

settlement

soil consolidation

prestressed concrete piles

foundation design