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Abstract

The problem of disposal of high-level radioactive waste has led to consideration of using the sediments of the deep-ocean floor as repositories and to the initiation of research to establish an understanding of the fundamental behaviour of deep-ocean sediments.

Previous work to establish the mechanical behaviour of these anisotropically (Ko), normally consolidated sediments has consisted generally of conventional testing (eg. strained controlled triaxial tests) on mainly isotropically consolidated specimens of various qualities of samples.

The work described in this thesis consisted of a series of triaxial stress path tests using microcomputer controlled hydraulic triaxial cells (Atkinson et al. 1985), to investigate the strength and stress-strain behaviour for mainly Ko consolidated "undisturbed" (tubed) and reconstituted specimens of deep-ocean sediments taken from two study areas in the North Atlantic Ocean.

The test results have been analysed within the framework of critical state soil mechanics to investigate sediment characteristics such as the state boundary surface, drained and undrained strength and stress-strain behaviour. While marked anisotropic behaviour is found in a number of respects, the results indicate that analysis in a critical state framework is as valid as for terrestrial sediments. Differences in behaviour between tubed and reconstituted specimens have been observed and the effect of the presence of carbonate has been investigated.

An attempt has been made to develop an elasto-plastic constitutive Ko model based on critical state concepts. This model has been found to agree reasonably well with experimental data for kaolin and deep-ocean sediments.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology > Department of Engineering School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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