Bonding degradation and stress–dilatancy response of weakly cemented sands

Porcino, D.; Marcianò, Vincenzo

doi:10.1080/17486025.2017.1347287

Cited by 26 publications

(9 citation statements)

References 34 publications

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“…The analysis of the results within the scope of Rowe's stress‐dilatancy theory (Rowe, ) and using equation (Porcino & Marcianò, ; Yu et al, ) to calculate reference lines for different values of c ′/ p ′( c ′: structuration strength, p′: mean effective stress) clearly indicates contributions of friction and dilation to reference sediment strength. The stress ratio η is defined according to equation ( q : deviatoric stress, M = 1.342: frictional constant defining the critical slope line).…”

Section: Resultsmentioning

confidence: 99%

Strain Rate‐Dependent Hardening‐Softening Characteristics of Gas Hydrate‐Bearing Sediments

Deusner

Gupta

Xie

et al. 2019

Geochem Geophys Geosyst

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The presence of gas hydrates (GHs) increases the stiffness and strength of marine sediments. In elasto‐plastic constitutive models, it is common to consider GH saturation (Sh) as key internal variable for defining the contribution of GHs to composite soil mechanical behavior. However, the stress‐strain behavior of GH‐bearing sediments (GHBS) also depends on the microscale distribution of GH and on GH‐sediment fabrics. A thorough analysis of GHBS is difficult, because there is no unique relation between Sh and GH morphology. To improve the understanding of stress‐strain behavior of GHBS in terms of established soil models, this study summarizes results from triaxial compression tests with different Sh, pore fluids, effective confining stresses, and strain histories. Our data indicate that the mechanical behavior of GHBS strongly depends on Sh and GH morphology, and also on the strain‐induced alteration of GH‐sediment fabrics. Hardening‐softening characteristics of GHBS are strain rate‐dependent, which suggests that GH‐sediment fabrics dynamically rearrange during plastic yielding events. We hypothesize that rearrangement of GH‐sediment fabrics, through viscous deformation or transient dissociation and reformation of GHs, results in kinematic hardening, suppressed softening, and secondary strength recovery, which could potentially mitigate or counteract large‐strain failure events. For constitutive modeling approaches, we suggest that strain rate‐dependent micromechanical effects from alterations of the GH‐sediment fabrics can be lumped into a nonconstant residual friction parameter. We propose simple empirical evolution functions for the mechanical properties and calibrate the model parameters against the experimental data.

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Section: Resultsmentioning

confidence: 99%

Strain Rate‐Dependent Hardening‐Softening Characteristics of Gas Hydrate‐Bearing Sediments

Deusner

Gupta

Xie

et al. 2019

Geochem Geophys Geosyst

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“…The drained stress‐strain response of the baseline sand (without hydrate) shows typical behavior for dense unbonded sand, where peak deviatoric stress is correlated with dilatancy of the sand (lateral expansion of the specimen), which can be suppressed by increases in applied confining stresses (Bolton, 1986; Coop, 1990; Rowe, 1962). In contrast, the formation of hydrate, using the excess gas method, leads to a bonded sand behavior, which includes significant increases in peak stress occurring at smaller axial strains, with a large degree of post peak strain softening, relative to the unbonded sand (Porcino & Marciano, 2017; Wang & Leung, 2008). For these specimens, peak stress is associated with cohesive bonding (hydrate at particle contacts) with minimal dilation having occurred at this stress.…”

Section: Discussionmentioning

confidence: 99%

The Change in Geomechanical Properties of Gas Saturated Methane Hydrate‐Bearing Sand Resulting From Water Saturation

2021

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Laboratory tests were carried out on gas‐saturated hydrate‐bearing sand (HBS) specimens that were subsequently water saturated to determine the influence of water saturation on their small‐strain (stiffness) and large‐strain (strength) behavior. Hydrate formed using the “excess gas” method led to significant increases in stiffness and strength of the sand. The magnitude increase in stiffness was largest for the lowest hydrate saturation tests and was sensitive to the distribution of hydrate within the sand. In contrast, increases in strength were directly related to increases in hydrate saturation, and to a lesser extent, on the applied confining stresses. Subsequent water saturation of these gas‐saturated HBS (achieved by flushing up to three times the pore volume of water through the HBS specimen) led to ∼90% and ∼70% reduction in stiffness and strength, respectively, along with a 37% reduction in hydrate volume (initial hydrate pore saturation ∼21.5%). Specimens with higher initial hydrate saturations (∼48%) saw slightly smaller reductions in stiffness and strength associated with ∼17% reduction in hydrate saturation. Changes in behavior appear to be related to the reduction of “cementing” hydrate at particle contacts through dissociation/dissolution of the hydrate, with remaining hydrate being more “pore filling.” Processes that may induce fluid flow in a natural gas‐saturated HBS, such as during the depressurization of the HBS reservoir during hydrate production, may lead to changes in hydrate morphology and affect the geomechanical properties of the HBS even when the HBS are still under hydrate stability conditions.

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“…Despite numerous studies conducted, limited attention has been paid to the constitutive behaviour of MICP-treated soils. Several constitutive models can be found in the literature that have been developed for cemented soils [46,[125][126][127][128][129][130][131][132][133][134]. However, only in a very limited number of cases have the models been either developed or validated specifically for MICP-treated soils.…”

Section: Constitutive Modellingmentioning

confidence: 99%

State-of-the-Art Review of Microbial-Induced Calcite Precipitation and Its Sustainability in Engineering Applications

et al. 2020

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Microbial-induced calcite precipitation (MICP) is a promising new technology in the area of Civil Engineering with potential to become a cost-effective, environmentally friendly and sustainable solution to many problems such as ground improvement, liquefaction remediation, enhancing properties of concrete and so forth. This paper reviews the research and developments over the past 25 years since the first reported application of MICP in 1995. Historical developments in the area, the biological processes involved, the behaviour of improved soils, developments in modelling the behaviour of treated soil and the challenges associated are discussed with a focus on the geotechnical aspects of the problem. The paper also presents an assessment of cost and environmental benefits tied with three application scenarios in pavement construction. It is understood for some applications that at this stage, MICP may not be a cost-effective or even environmentally friendly solution; however, following the latest developments, MICP has the potential to become one.

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Bonding degradation and stress–dilatancy response of weakly cemented sands

Cited by 26 publications

References 34 publications

Strain Rate‐Dependent Hardening‐Softening Characteristics of Gas Hydrate‐Bearing Sediments

Strain Rate‐Dependent Hardening‐Softening Characteristics of Gas Hydrate‐Bearing Sediments

The Change in Geomechanical Properties of Gas Saturated Methane Hydrate‐Bearing Sand Resulting From Water Saturation

State-of-the-Art Review of Microbial-Induced Calcite Precipitation and Its Sustainability in Engineering Applications

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