Detecting Emerging Sinkholes with FWD Testing

A local settlement on a runway was raising some concern at the Visby Airport on the Baltic island Gotland. The unevenness was local but the extent, the depth, and the reasons for the distress were unknown. The objective was to use falling weight deflectometer (FWD) data including time histories to detect areas prone to settlements. The testing was laid out as to cover settlement area. The spacing between tests was set up in 5 m intervals and some additional tests were done with larger in-between spacing to get a statistical base line for the field parameters. The following analysis consisted of a backcalculation of pavement layer moduli and an assessment of the layer dynamic properties by time histories. The time history evaluation can be plotted as a load-deflection graph. These have been calibrated to hysteresis. For the 70 kN load level the area outside the settlement displayed a dissipation of about 4 Nm, whereas the settlement showed a dissipation of over 20 Nm. Practically, this means that the settlement has not stopped and is continuing. A recommendation was made not to allow traffic near this area until further examinations. A thorough FWD testing of the airfield using this method was also recommended. As such the method seems promising in detecting emerging sinkholes at an early stage to avoid lengthy runway closures.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; Photos; References;
  • Pagination: 12p
  • Monograph Title: 2014 FAA Worldwide Airport Technology Transfer Conference Proceedings: Innovations in Airport Safety and Pavement Technology

Subject/Index Terms

Filing Info

  • Accession Number: 01538186
  • Record Type: Publication
  • Report/Paper Numbers: P10070
  • Files: TRIS, ATRI, USDOT
  • Created Date: Sep 9 2014 6:58AM