Undrained shear strength of clays as modified by pH variations

Spagnoli, Giovanni; Rubinos, David A.; Stanjek, Helge; Fernández-Steeger, Tomás Manuel; Feinendegen, Martin; Azzam, Rafig

doi:10.1007/s10064-011-0372-9

Cited by 51 publications

(23 citation statements)

References 42 publications

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“…In sand-bentonite mixture, the mobilised shear strength increases a little with an increase in acidity. This trend was also reported in the works of other researchers such as Spagnoli et al (2012). When pH value is decreased to 1, the maximum mobilised shear strength decreases more when compared with the neutral case.…”

Section: Stress-strain Behaviour and Pore Water Pressure Changessupporting

confidence: 82%

“…For instance, under medium acidic conditions, a sandkaolin mixture shows a little increase in resistance against liquefaction, while in sand-illite and sand-bentonite mixtures, the liquefaction resistance is decreased. Spagnoli et al (2012) studied the effects of pore water pH variations on the undrained shear strength of kaolinite and smectite clays and concluded that the shear strength increases with decrease in the pH value up to 3. Gratchev and Towhata (2013) studied the long-term effects of acidic pollutants on the stress-strain behaviour of two soils with different minerals of kaolinite and montmorillonite and concluded that with a decrease in pH from 7.3 to 6, the shear strength of both soils increases, but with another decrease to 4, the undrained shear strength of the soil with kaolinite minerals decreases.…”

Section: Introductionmentioning

confidence: 99%

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Effects of sulphuric acid pollutant on the shear behaviour and strength of sandy soil and sand mixed with bentonite clay

Hassanlourad

Khatami

Ahmadi

2016

International Journal of Geotechnical Engineering

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Mixture of sandy soil and bentonite clay can be used to seal the sanitary landfills and prevent the spread of leachate. Over time, this mixture may be subjected to different landfill contaminants, including acidic pollutants and shear strength variations. The objective of this research was to study the effects of sulphuric acid pollutant with pH values of 7, 3 and 1 on the shear behaviour and strength of clean sand and sand mixed with bentonite clay using common consolidated undrained triaxial tests. The tests results showed that the presence of acid in the soil pore water changes the shear behaviour pattern of the soil. Acid pollutant decreases the clean sand shear strength. In sand-bentonite mixture, the presence of sulphuric acid with a pH of 3 results in an increase in the shear strength, and with a pH of 1, it results in a decrease. Acid pollutant decreases the elastic modulus of the soil and increases the negative pore water pressure generated during shear.

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Section: Stress-strain Behaviour and Pore Water Pressure Changessupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Effects of sulphuric acid pollutant on the shear behaviour and strength of sandy soil and sand mixed with bentonite clay

Hassanlourad

Khatami

Ahmadi

2016

International Journal of Geotechnical Engineering

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“…The dissolution of the silica (S) and the metakaolin M-1000 by KOH leads to a modification of this Si-O-Si bond vibration band. From the literature, it is difficult to find evidence about the aluminum or silicon dissolution because some works are controversial [30,31]. These elements are harmonized to form the Si-O-Al and Si-O-K bonds [32] located in the 1100-950 cm −1 range.…”

Section: Evidence Of Various Geopolymerization Ratesmentioning

confidence: 99%

Role of the silica source on the geopolymerization rate

Autef

Joussein

Gasgnier

et al. 2012

Journal of Non-Crystalline Solids

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“…Spagnoli 2011b; Heuser et al 2012), chemical (e.g. Spagnoli et al 2012) and adhesive behaviour (e.g. Feinendegen et al 2012) of standard and natural clays.…”

Section: Physical and Mineralogical Properties Of The Claysmentioning

confidence: 98%

Mineralogical, Mechanical, and Electrical Properties of Clays and Their Relation to Clogging during Mechanical Tunnel Driving

Spagnoli¹,

Stanjek²,

Feinendegen³

et al. 2014

Geo-Congress 2014 Technical Papers

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One of the problems that can occur while boring through fine-grained soil is the adherence of clay to the EPB cutting wheel, inside the excavation chamber or in the transportation line, which might lead to long delays in the progress. Since the economic success of a tunneling project depends highly on the clogging potential of the encountered clay formations, it is of vital importance to understand this phenomenon and find possible solutions. Currently, there is no effective soil conditioning technique based on scientific data. Aim of this paper is to show how the mineralogical properties of clays play an important role for the mechanical and adhesive response. Mechanical laboratory tests, zeta (ζ) potential measurements, calculations and clogging tests were performed in order to link the adhesive properties with the clay mineralogical composition.

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Undrained shear strength of clays as modified by pH variations

Cited by 51 publications

References 42 publications

Effects of sulphuric acid pollutant on the shear behaviour and strength of sandy soil and sand mixed with bentonite clay

Effects of sulphuric acid pollutant on the shear behaviour and strength of sandy soil and sand mixed with bentonite clay

Role of the silica source on the geopolymerization rate

Mineralogical, Mechanical, and Electrical Properties of Clays and Their Relation to Clogging during Mechanical Tunnel Driving

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