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A vacuum-refilled tensiometer for deep monitoring of in-situ pore water pressure

Sadeghi, H ; Sharif University of Technology | 2021

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  1. Type of Document: Article
  2. DOI: 10.24200/sci.2018.5052.106
  3. Publisher: Sharif University of Technology , 2021
  4. Abstract:
  5. Real-time measurement of soil water pressure has been recognized as an essential part of investigating water ow in unsaturated soils. Tensiometry, amongst different measuring techniques, is a common method for direct evaluation of water pressure. However, the lower limit of measurable water pressure by a conventional tensiometer becomes even more limited by increasing its length in the vertical installation. This paper describes the development of a Vacuum-Refilled Tensiometer (VRT) for monitoring soil water pressure independent of installation depth. This is achieved by fixing the distance between pressure sensor and ceramic cup together with incorporating an ancillary vacuumre filling assembly into its design. The assembly allows for more efficient replacement of diffused air into the ceramic cup and reservoir with water. The new tensiometer is designed to withstand both negative and positive water pressure of up to almost one bar. In addition, the response time of the tensiometer to a change in negative water pressure for its working range (≥ -80 kPa) is very quick, in the order of seconds and one minute at most. The long-term performance of the new tensiometer is evaluated through a five-month monitoring program in the laboratory, simulating cyclic wetting and drying in the field. © 2020 Sharif University of Technology
  6. Keywords:
  7. Product design ; Soil moisture ; Stream flow ; Cyclic wetting and drying ; Direct evaluations ; Long term performance ; Measuring technique ; Monitoring programs ; Pore-water pressures ; Real time measurements ; Soil-water pressure ; Reservoirs (water) ; Design method ; Equipment component ; Monitoring system ; Pore pressure ; Porewater ; Tensiometer
  8. Source: Scientia Iranica ; Volume 27, Issue 2A , 2021 , Pages 596-606 ; 10263098 (ISSN)
  9. URL: http://scientiairanica.sharif.edu/article_20428.html