A constitutive model of frozen saline sandy soil based on energy dissipation theory

Salt content has been proven to be an important influencing factor on the mechanical properties of frozen saline soils, whose strength criterion is different from that of unfrozen saline soils or frozen soils without salts. In this paper, a series of conventional triaxial tests are carried out for frozen saline soils with sodium sulfate at a temperature of -6°C. A strength criterion of the frozen saline soils, including the influence of salt content, is established by using the generalized nonlinear strength theory. Based on conventional triaxial test results, a modified hydrostatic pressure expression is proposed according to the critical strength function of the modified Cam clay model in the meridian plane. The influence of salt content on the shear strength of the frozen saline soils is investigated according to their freezing temperature curves as well as the formation of salt and ice crystals. The relationship between salt content and friction angle is analyzed. The proposed strength criterion of frozen saline soil is proved to be reliable by extrusion elongation triaxial tests. This criterion can reasonably reflect the major nonlinear strength characteristics of frozen saline soils, including the influences of change in salt content, pressure melting, and ice crushing.Key words: sodium sulfate, frozen saline soil, strength criterion, freezing temperature, deviatoric plane.Résumé : La teneur en sel est avérée être un facteur d'influence importante sur les propriétés mécaniques des sols salins congelés, dont son critère de résistance est différent de celle des sols salins dégelés ou des sols gelés sans sels. Dans cet article, une série d'essais triaxiaux classiques sont effectués pour les sols salins congelés avec du sulfate de sodium à la température de -6°C. Un critère de résistance de sols salins congelés, y compris l'influence de la teneur en sel, est établi en utilisant la théorie généralisée de la résistance non linéaire. Sur la base de résultats d'essais triaxiaux classiques, une expression de pression modifiée hydrostatique est proposée, conformément à la fonction de la résistance critique du modèle Cam clay modifié dans le plan méridien. L'influence de la teneur en sel sur la résistance au cisaillement des sols salins congelés est étudiée en fonction de leurs courbes de température de congélation, et aussi la formation de cristaux de glace et de sel. La relation entre la teneur en sel et l'angle de frottement est analysée. Le critère de la résistance proposé de sol salin congelé est prouvé fiable par des essais triaxiaux d'allongement par extrusion. Ce critère peut raisonnablement refléter les principales caractéristiques de résistance non linéaire des sols salins congelés, y compris les influences de l'évolution de la teneur en sel, de la fusion et du broyage de glace sous pression. [Traduit par la Rédaction] Mots-clés : sulfate de sodium, sols salins congelés, critère de résistance, température de congélation, plan déviatorique.

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“…According to the experimental results, p t can be assumed as the following expression (Lai et al 2016):…”

Section: Modification For Generalized Effective Hydrostatic Pressurementioning

confidence: 99%

A strength criterion for frozen sodium sulfate saline soil

2016

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“…As is illustrated in Figure 1 from Lai et al [17], it can be found that the stress-strain curves go through the linear stage under relatively small axial strain to the elastoplastic stage. In addition, the curves present strain-softening phenomenon under low confining pressures and strain-hardening phenomenon under relatively high confining pressures.…”

Section: Test Results Analysismentioning

confidence: 92%

“…With respect to frozen soils, the bonding e ect of ice crystals and soil particles possesses tensile strength, which will be weakened due to the pressure melting under relatively high con ning pressures, similar to the cohesive behaviors of cemented clay. In the previous study [13,14,17,18,37], it is indicated that the strength of frozen soils increases rst and then decreases with the increase of con ning pressures. e maximum value q max of the q-p curve corresponds to failure mean stress p cr .…”

Section: A New Strength Criterion For Frozen Sandy Soilmentioning

confidence: 96%

“…Later, Nguyen et al [42] proposed that the CSL of the cemented clay eventually reduced to an asymptote coinciding with the CSL of natural clay. Lai et al [17] and Liao et al [18] employed a modi ed mean e ective stress expression to describe the strength criterion for frozen soils.…”

Section: A New Strength Criterion For Frozen Sandy Soilmentioning

confidence: 99%

“…Lai et al [16] established a parabolic curve for frozen silt soils in the meridian plane and Lade-Duncan model in the deviatoric plane to describe the shape function. Lai et al [17] and Liao et al [18] modified the hydrostatic pressure to simulate the strength in the q-p plane and employed a combination of LD and SMP models to describe the deviatoric plane. Lai et al [19] proposed a relationship between the first principal σ 1 and the third principal stress σ 3 , and then they established a nonlinear strength formula for frozen sandy soils.…”

Section: Introductionmentioning

confidence: 99%

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Investigation on the Nonlinear Strength Properties and Damage Statistical Constitutive Model for Frozen Sandy Soils

Liu

et al. 2018

Advances in Materials Science and Engineering

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ere are many flaws, such as fissures, cavities, and inclusions, in geomaterials, which make their mechanical properties with great randomness and uncertainty. Upon loading, the soil structure gradually losses the bearing capacity due to the transformation from microdefects to macroscopic breakage bands. Based upon the experimental data of frozen sandy soils, a new nonlinear strength equation between the first and third principal stresses was proposed, and then the nonlinear strength properties for frozen sandy soils in σ-τ plane were analyzed. In addition, by assuming that the microstrength of frozen sandy soil obeys the Weibull distribution function, a statistical damage constitutive model was established based upon the framework of continuum damage mechanics (CDM), with few parameters and a high accuracy. Compared with experimental data, the new model can well grasp the nonlinear strength properties and simulate the stress-strain relationships under different confining pressures for frozen sandy soils.

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A framework for constructing elasto‐plastic constitutive models for frozen and unfrozen soils

Guo

2021

Num Anal Meth Geomechanics

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The need for unified constitutive models for frozen and unfrozen soils in simulating frost heave and thaw consolidation has been recognized. However, a reliable and easy‐to‐implement model is not yet available. This paper extends the one‐dimensional elasto‐plastic model proposed by Yu et al. to solve multi‐dimensional problems. In the extended model, total and effective stresses are taken as the stress variables for frozen and unfrozen soils, respectively. A critical‐state‐based mode, Clay And Sand Model (CASM), is employed for soil at unfrozen states. The emphasis is placed on how a basic constitutive model for unfrozen soils is extended to describe the elasto‐plastic behavior for both unfrozen and frozen soils in two steps: (1) extension of the constitutive model from unfrozen to frozen soils by considering ice‐bonding effect, and (2) integration of descriptions for soils at unfrozen and frozen states using the concept of residual stress (by Nixon and Morgenstern). The freeze‐thaw cycling effect is naturally incorporated by the introduction of residual stress line that is used to determine the initial stress state and preconsolidation pressure of thawed soil. After being implemented into FORTRAN subroutines for ABAQUS, the performance of the proposed model is demonstrated by simulating triaxial compression tests on frozen sand at different temperatures under confining pressures, and freeze‐thaw cycling processes of silty clay under loading.

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A constitutive model of frozen saline sandy soil based on energy dissipation theory

Cited by 152 publications

References 49 publications

A strength criterion for frozen sodium sulfate saline soil

A strength criterion for frozen sodium sulfate saline soil

Investigation on the Nonlinear Strength Properties and Damage Statistical Constitutive Model for Frozen Sandy Soils

A framework for constructing elasto‐plastic constitutive models for frozen and unfrozen soils

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