Improved geotechnical properties in salt-treated highly sensitive landslide-prone clays

Abstract

Retrogressive or progressive landslides in slopes with highly sensitive quick clays may extend several hundred metres from where the slide was initiated. Reintroducing high salt contents to the pore water of leached low-saline quick clays may inhibit the development of such large landslides. Wells filled with potassium chloride (KCl) were installed in a quick-clay deposit at Dragvoll, Trondheim, Norway, to investigate the impact of changed pore-water chemistry on the geotechnical properties. The clay ceased to be quick due to favourable changed ion composition in the pore water, even at low salt contents, thus inhibiting retrogressive development. The apparent pre-consolidation stress (p′c) increased with increasing salt contents and the immediate collapse in structure typically seen in quick clays was avoided at loads just beyond p′c by changing the pore-water chemistry. Quick clay treated with KCl may therefore work as a barrier against retrogressive development and reduce the risk of initiation of progressive landslides.

Characterization of a gold tailings with hypersaline pore fluid

“…Rather, many tailings slurries contain appreciable quantities of dissolved solids at deposition (Poulos et al 1985;Fujiyasu and Fahey 2000;Al-Tarhouni et al 2011;Mundle et al 2012;Gorakhki and Bareither 2016), with salts most commonly making up a large proportion of the dissolved solids. This may be of importance for laboratory testing of tailings, as there is significant evidence as to the effects of salinity on geotechnical properties, including Atterberg Limits (Bjerrum 1954;Gorakhki and Bareither 2016), compressibility (Yukselen-Aksoy et al 2008), brittleness and sensitivity (Mitchell and Soga 2005;Helle et al 2018), and CSL elevation (Wang and Siu 2006). While tailings are often of low plasticity, being derived primarily from the crushing of rock, it is not currently clear below what threshold of plasticity (or other measure) the salt content of the pore fluid would not affect mechanical behaviour.…”

High‐resolution P‐ and S‐wavefield seismic investigations of a quick‐clay site in southwest of Sweden

“…Their strength was, thus, reduced to extremely low values. As a consequence, these deposits become vulnerable to collapse (Helle et al., 2018) and may liquefy when exposed to relatively low stress fields (e.g. strong rainfall, erosion, human activities such as excavations or waste dumping).…”

The Effects of Salt-Lake Salt Solution on the Strength of Expansive Soil

“…MgCl 2 solution, with the optimum concentration of 7%, is recommended as a viable soil improvement additive for both low-and high-swelling clays [20,21]. KCl changes pore-water chemistry to improve its geotechnical properties [22]. Salt content can affect freezing temperature (FT) and unconfined compressive strength (UCS) of lime-treated subgrade clay [23].…”