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Project Overview
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The stability of submerged slopes on the continental shelf is gaining larger attention worldwide as the economic
interest in offshore drilling and the number of related pipelines increase. Additionally, submarine slope failures
can trigger tsunami waves, with localized but potentially devastating effects.
These slides are characterized by gentle slopes (often less than 5°) and very large areas -up to several kilometers
across and hundreds of meters in thickness -in soft cohesive soil deposits. Seismic activity has been recognized
as one of the leading triggering mechanisms for submarine slope instabilities.
This project examines basic soil behavior observed through direct simple shear tests in order to develop analytical
methods for the prediction of deformations of submerged gentle slopes in soft clays during an earthquake.
A series of monotonic and cyclic simple shear tests was carried out on San Francisco Bay mud to characterize the
material. In particular, the testing program focused on the effect of the presence and direction of a shear stress
imposed during consolidation on the subsequent undrained shearing of the specimens. The test results, together
with additional data available in the literature, were used to develop a constitutive model (SIMPLE DSS) for the
specific stress conditions encountered in the simple shear test. The model is implemented in a finite element code
(AMPLE 2000) for seismic site response analysis, to get prediction of deformations and excess pore pressure development
during earthquake shaking. |
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