Use of fall cones to determine Atterberg limits: a review

O’Kelly, Brendan C.; Vardanega, Paul J.; Haigh, Stuart; Barnes, G. E.

doi:10.1680/jgeot.19.d.003

Cited by 8 publications

(2 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Note, the strength gain factor deduced for a given fine-grained soil is also dependent on the spread and accuracy of available strength data over the plastic range and whether the semi-logarithmic [74], bi-logarithmic [74] or multilinear [75] model approaches are used in the fitting. As hypothecated by O'Kelly et al [76] and then confirmed experimentally in Barnes [75]; for a given fine-grained soil, compared to the semi-or bi-logarithmic regression analysis with extrapolation along the single line to the PL HR water content value, the multilinear fitting, being more representative of the experimental s u − w relationship/curve, predicts (possibly by a substantial amount) a higher value of s u(PL) and hence also of the experimentally derived strength gain factor, R.…”

Section: Strength Range At the Pl Hr And Non-uniqueness With Pl 100mentioning

confidence: 90%

Review of Recent Developments and Understanding of Atterberg Limits Determinations

O’Kelly

2021

Geotechnics

Self Cite

View full text Add to dashboard Cite

Among the most commonly specified tests in the geotechnical engineering industry, the liquid limit and plastic limit tests are principally used for (i) deducing useful design parameter values from existing correlations with these consistency limits and (ii) for classifying fine-grained soils, typically employing the Casagrande-style plasticity chart. This updated state-of-the-art review paper gives a comprehensive presentation of salient latest research and understanding of soil consistency limits determinations/measurement, elaborating concisely on the many standardized and proposed experimental testing approaches, their various fundamental aspects and possibly pitfalls, as well as some very recent alternative proposals for consistency limits determinations. Specific attention is given to fall cone testing methods advocated (but totally unsuitable) for plastic limit determination; that is, the water content at the plastic–brittle transition point, as defined using the hand rolling of threads method. A framework (utilizing strength-based fall cone-derived parameters) appropriate for correlating shear strength variation with water content over the conventional plastic range is presented. This paper then describes two new fine-grained soil classification system advancements (charts) that do not rely on the thread-rolling plastic limit test, known to have high operator variability, and concludes by discussing alternative and emerging proposals for consistency limits determinations and fine-grained soil classification.

show abstract

Section: Strength Range At the Pl Hr And Non-uniqueness With Pl 100mentioning

confidence: 90%

Review of Recent Developments and Understanding of Atterberg Limits Determinations

O’Kelly

2021

Geotechnics

Self Cite

View full text Add to dashboard Cite

show abstract

“…Most suggestions in this context are essentially strengthbased methods, executed using FC or reverse-extrusion devices, which mainly work on the premise of associating the PL RT with a set value of undrained shear strength (a more detailed review of these methods is given in O'Kelly et al [34], Vardanega and Haigh [45] and O'Kelly [46,47]). However, several studies have demonstrated that when considering a range of different fine-grained soils, the PL RT (onset of brittleness) does not correspond to a fixed value of undrained shear strength [22,34,36,37,[48][49][50]. In other words, while strength-based "PL" determination methods arguably benefit from higher degrees of repeatability and reproducibility, they cannot replicate the standard PL RT testing condition, which assesses soil plasticity (toughness) behavior/properties.…”

Section: Introductionmentioning

confidence: 99%

Reappraisal of the ASTM/AASHTO Standard Rolling Device Method for Plastic Limit Determination of Fine-Grained Soils

Soltani

O’Kelly

2021

Geosciences

Self Cite

View full text Add to dashboard Cite

Given its apparent limitations, various attempts have been made to develop alternative testing approaches to the standardized rolling-thread plastic limit (PLRT) method (for fine-grained soils), targeting higher degrees of repeatability and reproducibility. Among these, device-rolling techniques, including the method described in ASTM D4318/AASHTO T90 standards, based on original work by Bobrowski and Griekspoor (BG) and which follows the same basic principles as the standard thread-rolling (by hand) test, have been highly underrated by some researchers. To better understand the true potentials and/or limitations of the BG method for soil plasticity determination (i.e., PLBG), this paper presents a critical reappraisal of the PLRT–PLBG relationship using a comprehensive statistical analysis performed on a large and diverse database of 60 PLRT–PLBG test pairs. It is demonstrated that for a given fine-grained soil, the BG and RT methods produce essentially similar PL values. The 95% lower and upper (water content) statistical agreement limits between PLBG and PLRT were, respectively, obtained as −5.03% and +4.51%, and both deemed “statistically insignificant” when compared to the inductively-defined reference limit of ±8% (i.e., the highest possible difference in PLRT based on its repeatability, as reported in the literature). Furthermore, the likelihoods of PLBG underestimating and overestimating PLRT were 50% and 40%, respectively; debunking the notion presented by some researchers that the BG method generally tends to greatly underestimate PLRT. It is also shown that the degree of underestimation/overestimation does not systematically change with changes in basic soil properties; suggesting that the differences between PLBG and PLRT are most likely random in nature. Compared to PLRT, the likelihood of achieving consistent soil classifications employing PLBG (along with the liquid limit) was shown to be 98%, with the identified discrepancies being cases that plot relatively close to the A-Line. As such, PLBG can be used with confidence for soil classification purposes.

show abstract

Discussion of “Mohajerani method: Tool for determining the liquid limit of soils using fall cone test results with strong correlation with the Casagrande test” by E. Hrubesova, B. Lunackova and M. Mohyla [Engineering Geology 278 (2020) 105852]

O’Kelly

Vardanega

Haigh

2022

Engineering Geology

Self Cite

View full text Add to dashboard Cite

Use of fall cones to determine Atterberg limits: a review

Cited by 8 publications

References 33 publications

Review of Recent Developments and Understanding of Atterberg Limits Determinations

Review of Recent Developments and Understanding of Atterberg Limits Determinations

Reappraisal of the ASTM/AASHTO Standard Rolling Device Method for Plastic Limit Determination of Fine-Grained Soils

Discussion of “Mohajerani method: Tool for determining the liquid limit of soils using fall cone test results with strong correlation with the Casagrande test” by E. Hrubesova, B. Lunackova and M. Mohyla [Engineering Geology 278 (2020) 105852]

Contact Info

Product

Resources

About