Repository logo
 

Discussion of “Determining Soil Plasticity Utilizing Manafi Method and Apparatus” by Masoud S. G. Manafi, An Deng, Abbas Taheri, Mark B. Jaksa, and Nagaraj HB, Published in Geotechnical Testing Journal 45, no. 4 (2022): 797–818

Accepted version
Peer-reviewed

No Thumbnail Available

Type

Article

Change log

Authors

o'Kelly, Brendan 
Vardanega, Paul 

Abstract

The liquid limit (LL) of a fine-grained soil is widely understood as relating to the water content (w) at which the soil has a small remolded undrained shear strength (cu) (e.g. Wroth & Wood 1978). When the fall-cone apparatus is used to measure LL (i.e., 〖LL〗_FC), this can be shown to be true based on plasticity theory (Koumoto & Houlsby, 2001). Whilst when measured using the Casagrande-cup apparatus (i.e., 〖LL〗_cup) there is a small variation in cu at the LL (i.e., cu LL(cup)) of soils having different levels of plasticity owing to dissimilar soil bulk density (ρ) at their LL states, as demonstrated by Haigh (2012). For a given Casagrande-cup apparatus type, the 〖LL〗_cup actually relates to a constant specific strength (i.e., cu LL(cup)/ρ) magnitude (Haigh, 2012). However, the strength value at LL is not explicitly stated and thus, whilst it is demonstrable that the strength magnitude at LL is approximately constant, the LL w itself (i.e., 〖LL〗_FC and 〖LL〗_cup) is defined by the method prescribed by a testing standard used for obtaining it (e.g., ASTM D4318-17e1, 2018; BS EN ISO 17892-12:2018+A1:2021 2021), in addition to the specifics of the equipment design which may vary between countries (Haigh, 2016).

Description

Keywords

Journal Title

Geotechnical Testing Journal

Conference Name

Journal ISSN

0149-6115

Volume Title

Publisher

ASTM International

Rights

Publisher's own licence