Percussion and Cone Methods of Determining the Liquid Limit of Soils: Controlling Mechanisms

Abstract

The mechanisms controlling the liquid limit of montmorillonitic and kaolinitic soils are different. The observation that the liquid limits obtained by both the conventional percussion method and the cone penetration method differ quite appreciably from each other at low and high plasticity ranges indicates that the mechanisms dominating the two testing procedures are different. The analysis of the results obtained from the present experimental investigation, and the results available in the literature prove that the viscous shear resistance primarily controls the percussion method of testing, and that the frictional shear resistance dominates the cone method of testing. Since the viscous shear resistance is primarily due to the double-layer held water, which is characteristic of montmorillonitic soils, and the liquid limit of montmorillonitic soil is primarily governed by the diffuse double layer thickness, the percussion method is well suited to montmorillonitic soils. Likewise, as the interparticle frictional resistance is due to the mode of particle arrangement in addition to mineral frictional characteristics, and the same primarily controls the liquid limit of kaolinitic soils, the cone method suits kaolinitic soils better.

Estimating Atterberg Limits of Fine‐Grained Soils by Visible–Near‐Infrared Spectroscopy

“…1c). The values obtained by the drop-cone method were marginally larger than the Casagrande method, and our results agree with those available in the literature (Spagnoli, 2012;Sridharan and Prakash, 2000). There were some discrepancies between the methods for the SL and PL, as can be seen in Fig.…”

Comparison of the Casagrande and Fall Cone Methods for Liquid Limit Determinations in Different Clay Soils

“…The LL p value is defined by the water content at which the cone penetrates 20 mm. This study evaluated the experimental data published by: Wasti (1987), Sridharan and Prakash (2000), Grabowska-Olszewska 2003 The experimental results of the LL c determination, that is, by the percussion method, were initially separated according to the base hardness of the Casagrande apparatus in two groups: B-01 (Casagrande apparatus hard base, LL c-hard base ) and B-02 (Casagrande apparatus soft base, LL c-soft base ).…”

“…The results of the data evaluated in B-02 are presented in figure 2. Sridharan and Prakash (2000) present experimental results obtained on pure kaolinite clays, smectites, and mixtures of bentonites and sands. Therefore, the data are presented separately in table 2, considering the mineralogy of the soils tested.…”

“…Figure 4a shows 28 pairs of data collected and grouped in the subgroup of B-02i, consisting of soils that are formed essentially by kaolinites and/or illites and published by Sridharan and Prakash (2000), Grabowska-Olszewska (2003), Özer (2009), Sousa (2011), and Nagaraj et al (2012). Figure 4b shows the 39 pairs of data collected and grouped in the subgroup of data B-02ii consisting of soils that are formed essentially by smectites and published by Sridharan and Prakash (2000), Grabowska-Olszewska (2003), and Nagaraj et al (2012). It can be seen in figure 4 that the transition between the values considered from low LL and high LL is about 60 %.…”

“…Kaolinite and smectite clays have different mechanisms that control the value of the liquid limit of these clays (Sridharan and Prakash, 2000): the LL of a smectite clay is mainly controlled by the presence of the adhesive water layer present in the clay mineral, while the kaolinite LL is mainly controlled by the forces between the particles of the clay mineral (for example, microstructure). Thus, in this article the correlations between LL c (with hard base and soft base devices) and LL p , for clays of different mineralogical compositions and LL values, are presented and discussed.…”