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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

INCLINOMETER - TIME DOMAIN REFLECTOMETRY COMPARATIVE STUDY

Four pairs of inclinometers and time domain reflectometry (TDR) cables were set up to make a side-by-side comparison of the performance of these systems in detecting slippage of soils in the shoulders of State Route 124 and State Route 338 in Meigs County, Ohio, within 50 ft (15 m) of the Ohio River. The soil consisted of sandy silt, silt, and clay on top of sedimentary rock. Borings were located 3-6 ft (1-2 m) from the edge of the pavement on the shoulder of the road at two locations on each road, with a TDR and an inclinometer located 3-5 ft (1-1.7 m) apart. Borings extended 10 ft (3.3 m) into the bedrock. Sixteen monthly readings were taken. At all four locations, the inclinometers detected shearing at depths ranging from 16 ft (4.9 m) to 40 ft (12.2 m). All of the detected shears were also identified by the TDR cables to within 1 ft (0.3 m). Water leakage occurred at shear locations on two TDR cables, preventing further monitoring below that depth on each; one inclinometer was also deformed beyond use at the same depth as the corresponding TDR cable water leakage. The cost for materials and casing for a single inclinometer installation is $484, versus $316 for a TDR, a reduction of 34.71%. The data acquisition and analysis equipment costs are $11,245 and $5,110, respectively, for a reduction of 54.56%. The total savings for a TDR system is 53.74%. For an additional $3105, remote monitoring of TDR installations can be added, eliminating the need for site visits until the cable becomes damaged; the TDR system savings even with the remote monitoring are still 27.27% over the inclinometer. Labor time costs for initial installation are comparable at 8-12 hrs, while the reading time is reduced from 10-30 min for an inclinometer to 1 min for a TDR system. TDR cables also have the advantage that they can be extended to a safer or more accessible point for reading.

  • Record URL:
  • Corporate Authors:

    Ohio University, Athens

    Ohio Research Institute for Transportation and the Environment
    141 Stocker Engineering and Technology Center
    Athens, OH  United States  45701-2979

    Ohio Department of Transportation

    Office of Research and Development
    1980 West Broad Street
    Columbus, OH  United States  43223

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Sargand, S M
    • Sargent, L
    • Farrington, S P
  • Publication Date: 2004-12

Language

  • English

Media Info

  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 115 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00987669
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/OH-2004/010,, Final Report
  • Contract Numbers: State Job No. 14798(0)
  • Files: TRIS, ATRI, USDOT, STATEDOT
  • Created Date: Mar 10 2005 12:00AM