AM Coatsworth, MSc, ACGI, DIC, MICE and NB Hobbs, MA, DIC, MICE, FGS. This paper was first published in GE’s October 1984 edition.
A distinction should be drawn between testing in which data capture and recording are carried out automatically (data logging) and that in which test control as well as data logging proceed without manual intervention.
Soil Mechanics Ltd. (SML) decided in 1982 that an automatically controlled triaxial apparatus was required to:
(1) Allow techniques such as stress path testing, anisotropic consolidation (e.g. with no lateral strain), and extension testing, which are labour intensive and hitherto seldom used in engineering practice, to be carried out automatically and hence to be much more readily available.
(2) Carry out conventional triaxial tests when not employed on non-standard tests.
(3) Stimulate thought on data logging and computer control of conventional oedometer and triaxial equipment.
Consideration was given to developing such automated triaxial apparatus in-house, but although this may ultimately be done, it was decided to reduce the lead time and learn from the developments of others. Custom-built computer-controlled triaxial equipment was seen in operation in soils laboratories at three universities, but the only equipment readily available was that manufactured by GDS Instruments Ltd. (GDS). This appeared to satisfy the above objectives, and was also sufficiently portable to be taken to site.