A noncontacting transducer for measurement of lateral strains

In order to study the anisotropic deformation behavior of soils in the triaxial test, three principal strains have to be measured accurately while the soil sample is subjected to three independent principal stresses. However, it appears that the technique of measuring small deformations of anisotropic soils has received relatively little attention. The authors have developed a new technique to measure the lateral strains, which does not require any contact of the transducer element with the soil surface. The details of the apparatus are presented in this technical note.