Sample Disturbance Effects in Silt

Carroll, Roselyn; Long, Michael

doi:10.1061/(asce)gt.1943-5606.0001749

Cited by 17 publications

(9 citation statements)

References 32 publications

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“…Sherbrooke (Lefebvre and Poulin 1979) and Laval samplers (LaRochelle et al 1981) typically provide high quality samples of clays, there is limited experience with these sampling techniques for low plasticity silts. Examples of collection of hand-carved and downhole Sherbrooke block samples in this material include Bradshaw and Baxter (2007), Carroll and Long (2017) and Blaker et al (2019).…”

Section: Silts and Intermediate Low Plasticity Soils Have Traditionalmentioning

confidence: 99%

“…As a result advanced laboratory testing (e.g. direct simple shear or triaxial compression) of these samples can lead to opposite effects of those often observed in naturally occurring structured clays, i.e., higher strength and stiffness properties than in situ values (Carroll and Long 2017;Lukas et al 2019). The dilative nature of many silts and other intermediate soils (silty sand, sandy silt, clayey silt, silty clay, etc.)…”

Section: Introductionmentioning

confidence: 99%

“…also results in strain hardening during undrained shear, and oftentimes, no unique undrained shear strength (peak) is observed (e.g. Fleming and Duncan 1990;Høeg et al 2000;Sandven 2003;Brandon et al 2006;Long 2007;Carroll and Long 2017). Consequently, significant uncertainties are associated with predicting the in situ undrained shear strength of silts using laboratory tests on apparently intact, so-called undisturbed samples.…”

Section: Introductionmentioning

confidence: 99%

“…Silts, however, may be undrained, partially drained, or drained during tube sampling depending on sampling rate, soil composition, type of sampler etc., and any potential volume changes occurring during and after sampling are unknown. The use of clay-based frameworks for silts has recently been shown to be misleading (Long et al 2010;Carroll and Long 2017;DeJong et al 2018;Lukas et al 2019) even though its use has been presented in the literature.…”

Section: Introductionmentioning

confidence: 99%

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Intact, Disturbed, and Reconstituted Undrained Shear Behavior of Low-Plasticity Natural Silt

Blaker

DeGroot

2020

J. Geotech. Geoenviron. Eng.

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This paper presents a laboratory investigation of undrained triaxial shear behavior of a natural low plasticity silt from Halden, Norway in the intact, disturbed and reconstituted states. Sherbrooke block sample and reconstituted specimens were subjected to simulated tube sampling in a triaxial stress path cell system prior to reconsolidation and undrained shear to assess the effects of disturbance on undrained shear behavior, undrained shear strength and effective stress friction angle. Shear stress and pore pressure development were evaluated relative to that measured for the undisturbed reference state taken as that measured on specimens from the intact block sample. Furthermore, specimens trimmed from fixed piston tube samples collected from the field site were also tested for comparative purposes. Collectively, the results demonstrate that neither the volumetric method of evaluating sample quality for clays nor shear wave velocity track sample disturbance well for this low plasticity silt. Relative to the reference intact block sample tests simulated tube sampling results in an increasingly pronounced dilative type behavior during post-disturbance undrained shear and a general increase in undrained shear strength. Specimens from the block sample that were subjected to simulated tube sample disturbance showed similar stress-strain behavior to that from conventional anisotropically consolidated triaxial compression tests conducted on specimens from the tube samples, suggesting that significant alteration of the intact soil state occurred during tube sampling. Practical suggestions for selection of undrained shear strength for intact low plasticity silts that exhibit dilative behavior such as the Halden silt are proposed.

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Section: Silts and Intermediate Low Plasticity Soils Have Traditionalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Intact, Disturbed, and Reconstituted Undrained Shear Behavior of Low-Plasticity Natural Silt

Blaker

DeGroot

2020

J. Geotech. Geoenviron. Eng.

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“…Only a few studies have evaluated the effects of tube sampling in silty soils (e.g., Long 2006;Pineda et al 2012;Arroyo et al 2015;Krage et al 2016;Carroll & Long 2017). Not surprisingly, the mechanisms of sampling disturbance in silty soils are still not well understood.…”

Section: Introductionmentioning

confidence: 99%

Experimental assessment of sampling disturbance in calcareous silt

Lim

Pineda

Boukpeti

et al. 2018

Géotechnique Letters

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A small-scale physical modelling program using particle image velocimetry and digital image correlation (PIV/DIC) techniques was designed to obtain a refined understanding of the disturbance experienced by calcareous silt during tube sampling. The influence of the sampler wall thickness (diameter to thickness ratio, B/t) and the tube penetration rate were evaluated by estimating displacement and strain fields around the tube sampler. The results indicate that sampling with a thin tube leads to a relatively narrow undisturbed zone located at the center of the tube, with a width slightly smaller than the tube radius. Opposite to what is suggested for soft clays, tube sampling tends to densify the calcareous silt. This aspect has an important influence on the assessment of sample quality in calcareous silt for offshore and onshore projects.

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A frozen soil sampling technique for granular soils and thermal modeling

Hani

Evirgen

2023

Bull Eng Geol Environ

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Sample Disturbance Effects in Silt

Cited by 17 publications

References 32 publications

Intact, Disturbed, and Reconstituted Undrained Shear Behavior of Low-Plasticity Natural Silt

Intact, Disturbed, and Reconstituted Undrained Shear Behavior of Low-Plasticity Natural Silt

Experimental assessment of sampling disturbance in calcareous silt

A frozen soil sampling technique for granular soils and thermal modeling

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