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Title: In-situ and Laboratory Cyclic Response of an Alluvial Plastic Silt Deposit
Current best practices for the assessment of the cyclic response of plastic silts are centered on the careful sampling and cyclic testing of natural, intact specimens. Side-by-side evaluation of in-situ and laboratory element test responses are severely limited, despite the need to establish similarities and differences in their characteristics. In this paper, a coordinated laboratory and field-testing campaign that was undertaken to compare the strain-controlled cyclic response of a plastic silt deposit at the Port of Longview, Longview, WA is described. Following a discussion of the subsurface conditions at one of several test panels, the responses of laboratory test specimens to resonant column and cyclic torsional shear testing, and constant-volume, strain-controlled cyclic direct simple shear testing are described in terms of shear modulus nonlinearity and degradation, and excess pore pressure generation with shear strain. Several months earlier, the in-situ cyclic response of the same deposit was investigated by applying a range of shear strain amplitudes using a large mobile shaker. The in-situ response is presented and compared to the laboratory test results, highlighting similarities and differences arising from differences in mechanical (e.g., constant-volume shearing; strain rate-effects) and hydraulic (e.g., local drainage) boundary conditions and the spatial variability of natural soil more » deposits. « less
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Proceedings of the 20th International Conference on Soil Mechanics and Geotechnical Engineering, Sydney 2021
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National Science Foundation
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