Offshore Technology Research Center

 

OTRC Project Summary

Project Title:

Model Offshore Soil Deposit: Design, Preparation, and Characterization

Prinicipal Investigators:

Roy Olson and Alan Rauch

Sponsor:

Minerals Management Service and Industry Consortium

Completion Date:

December, 2001

Final Report ID#

B109(Click to view final report abstract)

Note: This study was part of a broader project Suction Caissons: Model Tests (MMS Project #362)

A model offshore soil deposit was prepared to support continuing research into the capacity of suction caisson foundations in clay. There was an immediate requirement for new facilities to support lateral load testing on model suction caissons during the period from 1999 to 2001. In addition, there was an interest in obtaining additional material properties for the soil deposits used during axial loading tests performed on
model suction caissons between 1996 and 1998. Fine-grained soil was allowed to consolidate from a slurry to reflect the normally-consolidated highly-plastic clays found in the deepest waters of the Gulf of Mexico.

Preparation of a normally-consolidated fine-grained soil required simultaneous efforts on three fronts: preparation of slurry in a tank, determination of material properties for slurry, and development of techniques for predicting full-scale behavior on the basis of laboratory testing. The design of a matched slurry and tank required both knowledge of material properties and an analytical technique for using that knowledge. Efforts to date may best be described by proceeding from selection of the model soil through construction of the tank and observation of the slurry during large-scale consolidation. Comparisons may be made between observations made during large-scale consolidation and estimates made using numerical methods to extrapolate the results of laboratory consolidation tests. The design and implementation of equipment for measuring the shearing strength of the deposit logically follow.

Approximately eighty sequentially-numbered tests were performed during the course of this research. The consolidation data reported in this thesis are drawn from Tests 1, 2, 10, 11, 13, and 15 through 17, with each test identified by name where appropriate. The omitted tests were performed during either the evaluation of alternate kaolin suppliers or the refinement of testing equipment and techniques. The shearing
strength tests—Tests 18 through 75—are not specifically identified.

Related Publications: Rauch, A. F., Olson, R.E., Mecham, E. C., Pedersen, R.C. (2001). "A Laboratory Facility for Testing Model Suction Caissons." Proc., OTRC 2001 Intl Conf. on Geotechnical, Geological, Geophysical Properties Deepwater Sediments, Houston, TX, April. pp. 198-216

Pedersen, R. C., R. E. Olson, and A. F. Rauch (2003), “Shear and Interface Strength of Clay at Very Low Effective Stress”, ASTM Geotechnical Testing Journal, Vol. 26, No. 1, paper GTJ200310648-261

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