Volume 20, Issue 2 (June 1997)
Performance Evaluation of LDTs for Use in Triaxial Tests
The performance of local deformation transducers (LDTs) is described in the light of obtaining reliable data on the stiffness of geomaterial in a small-strain range. The components of LDTs and their functions are described, including recent modifications aimed at improving performance. Resolution, working range, and performance were critically examined with special reference to the evaluation of small strain elastic behavior of soil. LDTs in a lateral direction (or simply lateral LDTs) that are able to measure lateral strains precisely are also described. LDTs can underestimate the maximum elastic modulus measured during a small unload/reload cycle of a given geomaterial for no more than 2%, while they can measure strains less than 0.0005% without amplification. LDTs also function satisfactorily under submerged conditions in pressurized water for a long duration (at least 41 days).