Design, fabrication, and assembly of a large oedometer

A typical Casagrande-type oedometer cell is 76 mm in diameter and 19 mm high. It may perform satisfactorily in the measurements of consolidation parameters of homogeneous fine-grained soil specimens up to a maximum applied vertical stress of approximately 3 MPa. However, when it is required to evaluate the load-deformation characteristics of soil specimens containing relative large-diameter grain particles and/or at a considerably higher stress level, the existing apparatus is evidently inadequate. Therefore, an oedometer of 425 mm in internal diameter was designed, fabricated, and assembled at The University of Hong Kong. The consolidation stress that can be applied is up to 13.5 MPa. Specimen preparation and measurement procedure have to be developed to cope with the new apparatus. The design, fabrication, and assembly of the large oedometer are documented and discussed in this paper. Moreover, experimental procedure developed and measurement data demonstrating the applicability of the new apparatus are presented.