Evaluation of undrained shear strength of Swedish fine-grained sulphide soils

Abstract

In Swedish practice, there is a long tradition of evaluating undrained shear strength from fall-cone tests and field vane tests. During the last 20 years cone penetration tests have also become widely used. However, the results from all these test methods have to be evaluated using empirical factors. The factors generally used for Swedish clays are related to liquid limit and overconsolidation, but they are not applicable to all types of fine-grained soils and can often be improved by local calibration for the particular type of soil in the area of current interest. For this calibration, the results of direct simple shear tests and/or triaxial tests in the laboratory are normally used. This paper presents an evaluation for Swedish fine-grained sulphide soils, for which a general correction factor of 0.65 for field vane tests and fall-cone tests, a cone factor N kt of 20.2 for cone penetration tests and a relation c u,DSS /(σ′ c OCR −0.2 ) of 0.28 have been found. No correlations were found between these empirical factors and the clay content, liquid limit or organic content, but a relationship was found between the overconsolidation ratio and both the cone penetration test and the field vane test. The sulphide soils in question are found in northern Sweden along the coast of the Gulf of Bothnia. They are mostly classified as organic silt or organic clay, which is normally silty.

Stability for a high embankment founded on sulfide clay

“…Typical ranges for properties of these sulfide soils are total sulfur content of 0 . 1-2%, total iron content of 2-5%, and organic content of 2-7% of dry weight (Westerberg and Andersson, 2009). If the sulfide soil is subjected to oxygen (e.g.…”

Archives of Civil Engineering

“…It is worth to point out that correction factor was initially used only for cohesive soils [1] but afterwards it has been successfully used for organic soils as well i.e. μ = 0,5 for highly organic clays [12] or μ = 0,65 for sulphide organic silts or organic clays in Sweden [14].…”

“…Determination of the Atterberg limits is not limited to mineral soils and such tests can be done in organic soils [5,12]. Values of liquid limit and plastic limit in gyttja are commonly used for classification or for further correlations with physical [5,14] or mechanical [14] Apart from Atterberg limits the use of the parameter of consistency for organic soils is still debatable, what the authors undertake in this chapter. In manual tests, as pointed in ISO 14688-1:2002 [7], the consistency of cohesive soils, shall be identified as very soft, soft, firm, stiff and very stiff.…”

Disclosure of Scandinavian telecom companies’ corruption in Uzbekistan: The role of investigative journalists

“…Uzbekistan was not the only country where Telia was involved: May 2013 brought a new revelation about Telia’s role in the transfer of a major asset from the Azerbaijan state into the hands of companies with links to Azerbaijan President Aliyev’s family. The affair was characterised as the ‘biggest alleged bribe in Swedish history’, and the documentation was based on cooperation between Uppdrag Granskning (SVT), the OCCRP and the Swedish News Agency TT (Westerberg, 2015).…”