Development of a calibration chamber system for preparing large cohesive soil specimens

This paper describes an automated calibration chamber system used for preparing large size cohesive soil specimens and studying on in-situ testing devices. The procedure of preparing cohesive soil specimens, a two-stage consolidation technique, the first consolidation in consolidometer, then subsequent consolidation in calibration chamber, is briefly described. The system improves previous calibration chambers in that the two-stage consolidation is performed without moving the specimen, in that large size cohesive specimens, 1.2 m in diameter and I in high, can be prepared, and in that the latest computer program is used for various and accurate testing. Details on the data acquisition, control, monitoring systems, and instrumentations are summarized with the design of the calibration chamber system. The spatial pore water pressure distribution, dissipation, settlement, and water content during and after the two-stage consolidation are measured and investigated relevantly to specimen quality and consolidation characteristics.