Geotechnical characterization of Estonian oil shale semi-coke deposits with prime emphasis on their shear strength

Sedman, Annette; Talviste, Peeter; Mõtlep, Riho; Jõeleht, Argo; Kirsimäe, Kalle

doi:10.1016/j.enggeo.2012.02.002

Cited by 12 publications

(10 citation statements)

References 26 publications

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“…Moreover, the formation of the secondary Ca-Al-sulfate hydrate phase (ettringite) and Ca-Al-phase (hydrocalumite), a characteristic process in hydrated oil shale ash and semi-coke deposits [4,14,18,21,22], is subdued in the Enefit280 WHB ash. Ettringite formation requires the presence of soluble Ca, Al and sulfate [23].…”

Section: Discussionmentioning

confidence: 99%

Self-Cementing Properties and Alkali Activation of Enefit280 Solid Heat Carrier Retorting Ash

Paaver¹,

Paiste²,

Mõtlep³

et al. 2017

Oil Shale

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The composition and cementitious properties upon hydration and alkali activation of the solid heat carrier (SHC) ash produced in a new Enefit280 retort was studied. The Enefit280 waste heat boiler (WHB) ash is different from other SHC solid residues. It does not contain residual organics, but is characterized by a low content of reactive Ca-phases and the soluble amorphous (aluminium)-silicate phase/glass material. Cementation of Enefit280 ash upon hydration with plain water is limited and its uniaxial compressive strength stays < 4 MPa after 28 days of curing. Ash mixtures activated with sodium silicate based mixtures show higher compressive strength values, reaching > 10 MPa after 28 days of curing. The Enefit280 ash, compared to other ash types forming in the Estonian oil shale processing industry, has significantly poorer self-cementing properties. This needs to be taken into account when designing waste depositories, if other types of ash with better self-cementing properties are not co-deposited with this ash.

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Section: Discussionmentioning

confidence: 99%

Self-Cementing Properties and Alkali Activation of Enefit280 Solid Heat Carrier Retorting Ash

Paaver¹,

Paiste²,

Mõtlep³

et al. 2017

Oil Shale

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“…Through diffusion experiment is a widely used and accepted technique for measuring diffusive properties under steady state conditions (Descostes et al, 2008;Cave et al, 2009;Josh et al, 2012;Sedman et al, 2012).…”

Section: Diffusion Coefficientmentioning

confidence: 99%

“…However, in recent years comprehensive laboratory studies are conducted to characterize shale gas and oil shales in terms of alternative energy resources (Josh et al, 2012;Sedman et al, 2012). Characterization of pore structure, mineralogy, saturation, organic matter abundance, rock physics and geomechanical properties of gas and oil shales are the necessary parameters for exploration and development of these energy resources.…”

Section: Introductionmentioning

confidence: 99%

Chemoporoelastic characterization of Ghom shale

Kivi

Ameri

Ghassemi

2015

Journal of Petroleum Science and Engineering

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“…The mechanical properties of shale have been studied by many scholars. The anisotropy characteristics, compression strength, failure modes and microstructure of shale have been widely studied based on uniaxial and triaxial compression tests (Abousleiman et al, 2010;Sedman et al, 2012;Hou et al, 2015). Many researchers have carried out shear tests with different bedding orientations and found that the bedding planes were significantly weaker than those of the shale matrix (Abousleiman et al, 2010;Sedman et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…The anisotropy characteristics, compression strength, failure modes and microstructure of shale have been widely studied based on uniaxial and triaxial compression tests (Abousleiman et al, 2010;Sedman et al, 2012;Hou et al, 2015). Many researchers have carried out shear tests with different bedding orientations and found that the bedding planes were significantly weaker than those of the shale matrix (Abousleiman et al, 2010;Sedman et al, 2012). Tensile strength is a critical parameter that determines the resistance of shale to deformation and failure (Zhang et al, 2018) and fracturing in shale is produced mainly by tensile failure, so many researchers have performed a large number of Brazilian tests, which is a simple and effective way to measure the tensile strength of shale (Vervoort et al, 2014;Zhang et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

A Strain Rate Dependent Constitutive Model for the Lower Silurian Longmaxi Formation Shale in the Fuling Gas Field of the Sichuan Basin, China

Hou

Li²,

Zhang³

et al. 2019

Acta Geologica Sinica (Eng)

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Shale, as a kind of brittle rock, often exhibits different nonlinear stress-strain behavior, failure and timedependent behavior under different strain rates. To capture these features, this work conducted triaxial compression tests under axial strain rates ranging from 5×10 −6 s −1 to 1×10 −3 s −1 . The results show that both elastic modulus and peak strength have a positive correlation relationship with strain rates. These strain rate-dependent mechanical behaviors of shale are originated from damage growth, which is described by a damage parameter. When axial strain is the same, the damage parameter is positively correlated with strain rate. When strain rate is the same, with an increase of axial strain, the damage parameter decreases firstly from an initial value (about 0.1 to 0.2), soon reaches its minimum (about 0.1), and then increases to an asymptotic value of 0.8. Based on the experimental results, taking yield stress as the cut-off point and considering damage variable evolution, a new measure of micro-mechanical strength is proposed. Based on the Lemaitre's equivalent strain assumption and the new measure of micro-mechanical strength, a statistical strain-rate dependent damage constitutive model for shale that couples physically meaningful model parameters was established. Numerical back-calculations of these triaxial compression tests results demonstrate the ability of the model to reproduce the primary features of the strain rate dependent mechanical behavior of shale.

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Geotechnical characterization of Estonian oil shale semi-coke deposits with prime emphasis on their shear strength

Cited by 12 publications

References 26 publications

Self-Cementing Properties and Alkali Activation of Enefit280 Solid Heat Carrier Retorting Ash

Self-Cementing Properties and Alkali Activation of Enefit280 Solid Heat Carrier Retorting Ash

Chemoporoelastic characterization of Ghom shale

A Strain Rate Dependent Constitutive Model for the Lower Silurian Longmaxi Formation Shale in the Fuling Gas Field of the Sichuan Basin, China

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