Comparisons of overstress theory with an empirical model in creep prediction for cohesive soils

Kim, Dae Kyu

doi:10.1007/bf02831485

Cited by 3 publications

(4 citation statements)

References 1 publication

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“…Research methods for the rheological model are mainly divided into empirical equation and component combination [8,9]. Logarithmic, exponential, and power functions are adopted in the empirical equation to describe the strain-time relation with few fitting parameters and strong pertinence based on the creep test results.…”

Section: Introductionmentioning

confidence: 99%

“…ε is the creep acceleration. Equations (8) and (9) show that strain ε is the function of time t during the coal creep process. Only when E 3 < 0 can the creep rate and creep acceleration be above zero, because the acceleration index n, yield stress σ s , and nonlinear viscosity coefficient η(t) are the constants that are greater than zero, indicating that the strain of the nonlinear viscoelastic-plastic body will increase over time.…”

Section: Introduction Of Negative Elastic Modulus E 3 (Shear Modulus mentioning

confidence: 99%

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Nonlinear Viscoelastic–Plastic Creep Model Based on Coal Multistage Creep Tests and Experimental Validation

Zhang

Cong-hui

2019

Energies

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The development of fractures, which determine the complexity of coal creep characteristics, is the main physical property of coal relative to other rocks. This study conducted a series of multistage creep tests to investigate the creep behavior of coal under different stress levels. A negative elastic modulus and a non-Newtonian component were introduced into the classical Nishihara model based on the theoretical analysis of the experimental results to propose a nonlinear viscoelastic–plastic creep model for describing the non-decay creep behavior of coal. The validity of the model was verified by experimental data. The results show that this improved model can preferably exhibit decelerating, steady state, and accelerating creep behavior during the non-decay creep process. The fitting accuracy of the improved model was significantly higher than that of the classical Nishihara model. Given that acceleration creep is a critical stage in predicting the instability and failure of coal, its successful description using this improved model is crucial for the prevention and control of coal dynamic disasters.

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Section: Introductionmentioning

confidence: 99%

Section: Introduction Of Negative Elastic Modulus E 3 (Shear Modulus mentioning

confidence: 99%

Nonlinear Viscoelastic–Plastic Creep Model Based on Coal Multistage Creep Tests and Experimental Validation

Zhang

Cong-hui

2019

Energies

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“…Based on experimental investigations, various viscoelasticplastic models [11,12] taking into account soil and rock microstructure and damage have been proposed. ese models can be classified into three categories: empirical models, rheological models, general stress-strain-time models [7,13], and damage-involved models [14,15]. e empirical models are mainly obtained by fitting the experimental results from creep tests; due to its relatively simple mathematical formulation and few parameters, the empirical models [16][17][18] are widely used to simulate the creep behavior of various soils.…”

Section: Introductionmentioning

confidence: 99%

“…e empirical models are mainly obtained by fitting the experimental results from creep tests; due to its relatively simple mathematical formulation and few parameters, the empirical models [16][17][18] are widely used to simulate the creep behavior of various soils. Rheological models usually use differential representation, visualizing the material by the elementary mechanical models composed of elastic springs, plastic sliders, and viscous dashpots [13,19,20]. e general stress-strain-time models are often in the incremental form and usually implemented in numerical software [21], such as the overstress model proposed by Karstunen and Yin [22] and the further extended overstress model by Yin et al [23].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Theoretical Studies on the Creep Behavior of Bayer Red Mud

Zhao

Huang

Shu

et al. 2018

Advances in Civil Engineering

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Long-term stability and safety of the Bayer red mud (BRM) disposal field is very important for the local residents’ life, which necessitates the knowledge of its creep behavior. In order to investigate the creep behavior of BRM, a series of triaxial drained creep tests were conducted by using an improved triaxial creep apparatus. The results indicate that the creep behavior of BRM is significant with confining and deviatoric stresses being critical factors. The creep strain is in a nonlinear relationship with stress and time, and a larger deviator stress will lead to a larger creep strain. The main failure mechanism of BRM is plastic shear, accompanied by a significant compression and ductile dilatancy. Based on the test results, two well-established creep models, the Burgers creep model and Singh–Mitchell creep model, were used to comparatively analyze the creep behavior of the Bayer red mud under a certain stress level. Then, an improved Burgers creep damage constitutive model with the addition of a damage variable was proposed, whose parameters were also analyzed in detail. The comparison of the calculated values of the creep model and the experimental values shows that the proposed creep damage model can better describe the instant elastic deformation, attenuation creep, steady-state creep, and accelerated creep stages of the Bayer red mud.

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An isochronous stress ratio logarithmic strain curve based clay creep model considering the effects of hardening and damage

Wang,

Tang,

Ren

et al. 2024

Sci Rep

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Creep is one of the typical mechanical properties of clay, and studying the creep mechanical properties of clay is of great significance to construction projects in clay sites. This study conducted creep tests on Chengdu clay and found that the soil mass underwent elastic deformation, decay creep deformation, steady-state creep deformation, and accelerated creep deformation. The isochronous stress ratio-logarithmic strain curves and their mathematical models were proposed to thoroughly analyze clay creep mechanical properties. Creep automatic feature points, such as linear elastic extreme point, initial yield point, long-term strength point, and plastic point, were identified on the curve. Considering the hardening and damage effects during creep loading, linear elastic and viscoelastic elements considering the time-dependent damage, a viscoplastic element considering the load hardening effect, and viscoplastic and plastic elements considering the load damage effect were established based on the element model and the Riemann–Liouville fractional derivative. Based on the mechanical properties of the whole clay creep process, the creep mechanical feature points, and the established element model, a clay creep model was proposed considering the hardening and damage effects. The rationality and regularity of the creep model were verified using the creep test data. This research accurately revealed the creep mechanical properties of clay and facilitated soil deformation prediction, thus providing technical guidance and references for construction projects in clay sites.

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Comparisons of overstress theory with an empirical model in creep prediction for cohesive soils

Cited by 3 publications

References 1 publication

Nonlinear Viscoelastic–Plastic Creep Model Based on Coal Multistage Creep Tests and Experimental Validation

Nonlinear Viscoelastic–Plastic Creep Model Based on Coal Multistage Creep Tests and Experimental Validation

Experimental and Theoretical Studies on the Creep Behavior of Bayer Red Mud

An isochronous stress ratio logarithmic strain curve based clay creep model considering the effects of hardening and damage

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