Stress tests of ODP Site 131-808 sediments

Fuente: PANGAEA
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Autori principali: Feeser, Volker, Moran, Kate, Brückmann, Warner
Natura: Dataset Open Access
Lingua:en
Pubblicazione: PANGAEA 1993
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author Feeser, Volker
Moran, Kate
Brückmann, Warner
author_facet Feeser, Volker
Moran, Kate
Brückmann, Warner
collection Datos científicos de ciencias marinas y ambientales
contents Sediments undergoing accretion in trench-forearc systems are subjected to conditions of large lateral thrusting. This stress regime controls the mechanism of faulting as well as the yield and strength properties of the sediment. Understanding them is therefore crucial for the construction of quantitative models of sediment dynamics in convergent margin settings. For this purpose triaxial and oedometer tests were performed on six whole-round core samples recovered from Site 808 from depths between 173 and 705 mbsf. Samples from five depth intervals were subjected to a triaxial test program that was primarily designed to define yield and strength behavior. Test specimens were cut parallel and normal to the core axis. Additional five oedometer tests with similarly prepared specimens were performed on samples from four depth intervals to evaluate the directional state and degree of sediment compaction. Test results show that the degree of sediment compaction is higher than expected from overburden. This overcompaction increases with depth. A well-developed mechanical anisotropy is evident in all samples tested, regardless of their depth and lithology. Values of yield limit, stiffness, and shear strength are up to 40% higher in the horizontal direction compared to the vertical direction. In addition the test data demonstrate that the axis of the volumetric yield loci have rotated into extensional stress field. This verifies that the mechanical state of sediment in the accretionary wedge is controlled by in-situ stress conditions of extensional nature. The coefficients of lateral stress inferred suggest that the extensional stress regime becomes increasingly effective with depth.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_785258
institution PANGAEA
language en
publishDate 1993
publisher PANGAEA
record_format pangaea
spellingShingle Stress tests of ODP Site 131-808 sediments
Feeser, Volker
Moran, Kate
Brückmann, Warner
131-808; 131-808B; 131-808C; 131-808G; COMPCORE; Composite Core; DRILL; Drilling/drill rig; Joides Resolution; Leg131; Ocean Drilling Program; ODP; Philippine Sea
Sediments undergoing accretion in trench-forearc systems are subjected to conditions of large lateral thrusting. This stress regime controls the mechanism of faulting as well as the yield and strength properties of the sediment. Understanding them is therefore crucial for the construction of quantitative models of sediment dynamics in convergent margin settings. For this purpose triaxial and oedometer tests were performed on six whole-round core samples recovered from Site 808 from depths between 173 and 705 mbsf. Samples from five depth intervals were subjected to a triaxial test program that was primarily designed to define yield and strength behavior. Test specimens were cut parallel and normal to the core axis. Additional five oedometer tests with similarly prepared specimens were performed on samples from four depth intervals to evaluate the directional state and degree of sediment compaction. Test results show that the degree of sediment compaction is higher than expected from overburden. This overcompaction increases with depth. A well-developed mechanical anisotropy is evident in all samples tested, regardless of their depth and lithology. Values of yield limit, stiffness, and shear strength are up to 40% higher in the horizontal direction compared to the vertical direction. In addition the test data demonstrate that the axis of the volumetric yield loci have rotated into extensional stress field. This verifies that the mechanical state of sediment in the accretionary wedge is controlled by in-situ stress conditions of extensional nature. The coefficients of lateral stress inferred suggest that the extensional stress regime becomes increasingly effective with depth.
title Stress tests of ODP Site 131-808 sediments
topic 131-808; 131-808B; 131-808C; 131-808G; COMPCORE; Composite Core; DRILL; Drilling/drill rig; Joides Resolution; Leg131; Ocean Drilling Program; ODP; Philippine Sea
url https://doi.org/10.1594/PANGAEA.785258