Needle probe application for high-resolution assessment of soil spatial variability in the centrifuge

Zhihua Li, Bruce L. Kutter, Daniel W. Wilson, Kenneth Sprott, Jong-Sub Lee, J. Carlos Santamarina

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

This paper addresses the development of an electrical resistivity needle probe to be deployed during centrifuge model testing to assess with high-resolution the spatial variability of soil electrical resistivity. The probe is able to detect thin layers and accurately resolve interfaces between soil layers. The prototype probes are made from thin, stainless steel needles, with an insulated wire inserted into the needle, and bonded to it with epoxy resin, to form a coaxial probe (Cho et al. 2004). Different tip shapes including single-wedge, double-wedge and cone have been developed to optimize the spatial resolution of porosity, soil interfaces and layering. The calibration and testing of the needle probe has been conducted both at Georgia Tech and UC Davis. This paper presents results of resistance versus depth and porosity versus depth, and compares the porosity based on measurement of mass and volume with the calculated porosity based on the needle probe measurements. Consequently, insertion effects are discussed and theoretical explanations are given. For its deployment in the centrifuge, a special needle probe tool has been developed to be operated by the new NEES robot. Instrumentation, data acquisition and data processing issues associated with the needle probe robot tool are discussed. The basis for selection of materials, probe tip geometry, and the optimum frequency of AC electrical measurements is explained.

Original languageEnglish
Title of host publicationGeotechnical Special Publication
Pages2087-2101
Number of pages15
Edition130-142
Publication statusPublished - 2005
Externally publishedYes
EventGeo-Frontiers 2005 - Austin, TX, United States
Duration: 2005 Jan 242005 Jan 26

Other

OtherGeo-Frontiers 2005
CountryUnited States
CityAustin, TX
Period05/1/2405/1/26

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Keywords

  • Centrifuge
  • Needle probe
  • NEES
  • Porosity
  • Resolution
  • Robot
  • Spatial variability

ASJC Scopus subject areas

  • Building and Construction
  • Architecture
  • Soil Science

Cite this

Li, Z., Kutter, B. L., Wilson, D. W., Sprott, K., Lee, J-S., & Santamarina, J. C. (2005). Needle probe application for high-resolution assessment of soil spatial variability in the centrifuge. In Geotechnical Special Publication (130-142 ed., pp. 2087-2101)