Design and construction of the large-scale tri-axial testing apparatus
In the early 1980's in South Africa, the work of J.H. Maree pioneered the modelling and design of pavements with granular bases especially high quality base layers. Since then very little has been done to create more realistic and sophisticated models to enable more accurate designs to be carried out. South African models include only rudimentary stress-dependent functions e.g. M r = K 1θ K2 model. Although these models take account of stress dependences, they are not considered accurate enough for highly realistic pavement modelling. A motivation for the design and development of a large-scale tri-axial apparatus is to move towards more accurate and reliable functional specifications and design models for road bases and sub-bases in South Africa, where granular materials comprise more than 98% of total pavement layers. This paper reports on the design and construction of the large-scale apparatus, and on the materials to be tested. The challenges encountered and the manner in which they have been addressed, are also discussed. © 2007 Taylor & Francis Group, London.