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Title: Monotonic, Cyclic, and Post-Cyclic Response of Willamette River Silt at the Van Buren Bridge
This study presents a laboratory investigation of the monotonic, cyclic, and post-cyclic responses of a lightly overconsolidated, low plasticity silt deposit conducted to support the geotechnical design of a proposed bridge replacement crossing the Willamette River in Corvallis, OR. The design seismic hazard corresponded to the 975-year return period with the Cascadia Subduction Zone contributing the greatest portion of the hazard. The response of the intact, natural specimens was compared to that of specimens reconstituted from the same material for comparison of the effect of soil fabric. Constant-volume cyclic stress controlled direct simple shear tests (CDSS) conducted on the low plasticity silt deposit showed cyclic mobility type behavior and increases in cyclic resistance with OCR. The exponent of the power relationship between cyclic resistance ratio (CRR) and the number of cycles, N, was shown to be smaller than that commonly assumed within the simplified method for cyclic softening of fine-grained plastic soil. Despite higher density, the reconstituted specimens exhibited approximately 16% lower cyclic resistance than their undisturbed counterparts, indicating the importance of soil fabric on the cyclic resistance of natural silt soils. The post-cyclic volumetric strain of the silt deposit was found to be independent of OCR and increased with more » the maximum excess pore pressure ratio generated during the cyclic tests. « less
Authors:
; ; ; ; ;
Editors:
Lemnitzer, A.; Stuedlein, A.W.
Award ID(s):
1663654
Publication Date:
NSF-PAR ID:
10349589
Journal Name:
Geo-Congress 2022
Page Range or eLocation-ID:
431 to 443
Sponsoring Org:
National Science Foundation
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