Laser Measurement of Radial Displacements in Triaxial Tests: ENSG

The measurement of strain in triaxial shear tests and the subsequent determination of the key soil parameters (shear modulus, elastic modulus, etc.) is critical to understanding the mechanical behaviour of soils.

Most currently available systems need to set the measuring system directly on the soil sample to be tested, which can disrupt the soil and therefore the results (Cole 1978, Clayton et al. 1989). Thus, some authors have implemented contactless systems, including devices based on the use of a  laser spot (eg Romero 1999; Dasari 2002; Messerklinger & Springmann 2007). These devices have the advantage of not requiring contact with the specimen and so do not disrupt the mechanical behaviour of soil.

The Solution

ENSG & GDS Instruments developed a device to monitor the radial profile of the specimen whilst under test using highly accurate laser precision. The  system is based on the use of two laser profilers supplied by Keyence (The LJ-G80 lasers). The lasers monitored a 32mm length on the sample from a distance of 80 mm. The sensors were installed on to a modified conventional triaxial cell. Download the PDF below file for the complete case study.

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