Geomechanics and Engineering

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A novel triaxial testing device for unsaturated soils with measurement of suction and volumetric strains

  • Qian-Feng Gao (School of Traffic & Transportation Engineering, Changsha University of Science & Technology) ;
  • Mohamad Jrad (Laboratoire d'Etude des Microstructures et de Mecanique des Materiaux, Universite de Lorraine - CNRS UMR 7239, Arts et Metiers ParisTech) ;
  • Mahdia Hattab (Laboratoire d'Etude des Microstructures et de Mecanique des Materiaux, Universite de Lorraine - CNRS UMR 7239, Arts et Metiers ParisTech) ;
  • Said Taibi (Laboratoire LOMC, Universite Le Havre Normandie & CNRS) ;
  • Jean M. Fleureau (Laboratoire de Mecanique de Paris-Saclay, Universite Paris-Saclay, CentraleSupelec, ENS Paris-Saclay)
  • Received : 2023.04.13
  • Accepted : 2024.01.13
  • Published : 2024.04.25
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Abstract

Standard triaxial cells are commonly used to measure the mechanical behavior of saturated soils. However, this type of standard system is difficult to use for unsaturated soil specimens since it cannot measure the changes in the pore-air volume and pressure. This paper proposes to extend the measurement possibilities of the standard triaxial testing device in a simple way and to adapt it to partially saturated soils. The system is supplied by two hygrometers installed at each end of the cylindrical unsaturated specimen to measure local relative humidity, which allows the derivation of suction. The volumetric strain of the specimen is calculated by analyzing digital photos captured from the outside of the transparent cell wall. Specimens made of kaolin clay, having different hydraulic properties, were tested to verify the reliability of the measurements, and thus, the relevance of the proposed techniques to study the mechanical behavior of unsaturated soils.

Keywords

References

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