Evaluation of Critical Dynamic Stress and Accumulative Plastic Strain of an Unbound Granular Material Based on Cyclic Triaxial Tests

Zhang, Qishu; Leng, Wei; Bin, Zhai; Xu, Fang; Dong, Junli; Qi, Yang

doi:10.3390/ma14195722

Cited by 8 publications

(6 citation statements)

References 63 publications

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“…The accumulative plastic strain-time curves of geotechnical materials term alternating load can be categorized into three types [40]: (1) steady curv curve; (3) failure curve, as shown in Figure 4a. The dynamic stress that make lative strain-time curve evolve into a critical curve is called critical dynam and accumulative strain-time curves evolve into steady or failure curves, d whether the dynamic stress is lower or higher than 𝜎 .…”

Section: Deformation Characteristics Of Clay Under Alternating Loadmentioning

confidence: 99%

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A Variable-Order Dynamic Constitutive Model for Clay Based on the Fractional Calculus

Zhang

Chen

et al. 2022

Applied Sciences

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To accurately describe the deformation characteristics of clay under long-term cyclic load, based on fractional calculus theory, elastoplastic theory and the basic element model, a variable-order fractional dynamic model designed to predict accumulative strain of clay was exhibited. Firstly, the cyclic load was separated into static and alternating load in accordance with cyclic load characteristics, and the strain of clay under static and alternating load was analyzed. Then, on the basis of the variable-order Abel dashpot model, rheological theory and elastoplastic theory, the expressions of the rheological constitutive model and strain response were both obtained. Finally, in combination with the undrained dynamic triaxial testing of Zhan Jiang clay and Tian Jin soft clay, a series of analyses was carried out on the effectiveness and parameter sensitivity of the model when subjected to long-term cyclic loading. By comparing the dynamic constitutive model with pre-existing models, the superiority of the dynamic constitutive model is revealed. The results show that the dynamic constitutive model can characterize properly the deformation characteristics of clay under the action of long-term cyclic loading, especially in its accelerating stage. The parameter sensitivity of the model exhibits a growing trend with the increment of loading duration.

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Section: Deformation Characteristics Of Clay Under Alternating Loadmentioning

confidence: 99%

“…The accumulative plastic strain-time curves of geotechnical materials under long-term alternating load can be categorized into three types [40]: (1) steady curve; (2) critical curve;…”

Section: Deformation Characteristics Of Clay Under Alternating Loadmentioning

confidence: 99%

A Variable-Order Dynamic Constitutive Model for Clay Based on the Fractional Calculus

Zhang

Chen

et al. 2022

Applied Sciences

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“…While much documentation exists regarding the need to consider the viscoelastic behavior of asphalt concrete (AC) mixtures more representatively [7][8][9], the actual behavior of the unbound granular materials located in the base and sub-base layers is usually overlooked. Multiple studies over the years have recognized the significance of the behavior of unbound granular materials [10][11][12], which is normally nonlinear elastic. Other studies have additionally focused on the base material Designs 2023, 7, 142 2 of 14 cross-anisotropy [13][14][15], as well as on the joint modeling of the unbound materials' nonlinear and anisotropic behavior [16][17][18][19][20].…”

Section: Introduction 1overviewmentioning

confidence: 99%

“…Consistent research interests are observed that investigate correlations between inputs during the design of the unbound materials and pavement performance. To this end, the use of finite element method (FEM) tools is an efficient approach to investigate pavement responses' sensitivity with respect to variations in several geometric or material parameters that affect pavement design [10,22,23]. Considering that during a pavement's construction process, deviations between the design and the as-built values of either the pavement's geometric or material properties frequently occur, leading to additional short-term or long-term costs for the road agencies, it always remains challenging to access efficient tools to accurately predict the impact that such deviations may potentially have on future pavement responses.…”

Section: Introduction 1overviewmentioning

confidence: 99%

Pavement Analysis with the Consideration of Unbound Granular Material Nonlinearity

Gkyrtis

2023

Designs

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Accurate pavement design and evaluation requires the execution of response analysis. Pavement materials’ behavior does not necessarily conform to the assumptions of the multi-linear elastic theory usually adopted during pavement analysis. In particular, the unbound granular materials located in the base and sub-base layers behave in a nonlinear elastic manner, which can be captured through advanced constitutive modeling of their resilient modulus. The finite element method enables us to code constitutive models and quantify potential variations in pavement responses because of different mechanistic assumptions. In this study, variations in response are investigated for a typical structure of a flexible pavement considering the nonlinear anisotropic behavior of the unbound materials together with their initial stress–strain state. To demonstrate the impact of their behavior on the outcome of pavement analysis, variable asphalt concrete layer thicknesses and moduli are assumed, such that they cover a large spectrum of roadways. It was found that pavement responses can be calculated up to 3.5 times higher than those retrieved from the conventional linear analysis. This comparison means that the alterative mechanistic modeling of the unbound granular materials can be proved to be more conservative (i.e., leading to higher strains) in terms of pavement design and analysis. From a practical perspective, this study alerts pavement scientists and engineers engaged in pavement design to a more reliable performance prediction, which is needed to bridge the gap between advanced modeling and routine analysis.

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“…However, increasing train speeds and axle loads can inevitably lead to an increase in the load frequencies and magnitudes acting on the railway subgrade and accelerate the micro-structural damage of the subgrade. Consequently, a series of possible railroad subgrade diseases, such as unacceptable settlement, subgrade slope instability, cracking in the shoulder section, and ballast pockets would develop and seriously hamper the operational safety and efficiency of existing railways [ 1 , 2 ]. These diseases are closely related to a poor stress state of the subgrade soil and a lack of lateral deformation constraint of the subgrade slope.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Response Characteristics of Railway Subgrade Using a Newly-Developed Prestressed Reinforcement Structure: Case Study of a Model Test

et al. 2022

Self Cite

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Poor subgrade conditions usually induce various subgrade diseases in railways, leading to some adverse influences. An innovative technology that involves installing a prestressed reinforcement structure (PRS) that consists of steel bars and lateral pressure plates (LPP) for subgrade was introduced to improve its stress field and provide compulsive lateral deformation constraints for slope. In this study, an investigation into the dynamic acceleration responses of railway subgrade strengthened according to different PRS schemes was presented using a 1:5 scale model test, aiming to explore the effects of the axle load, the reinforcement pressure, and the loading cycles on the acceleration characteristics of the subgrade. The experimental results showed that (1) after pretension of the steel bar, prestress loss occurred due to the soil creep behavior and group anchor effect, so a moderate amount of over-tension in practices would be necessary; (2) a distinctive periodical behavior of subgrade subjected to the cyclic loads was observed, the horizontal accelerations were generally less than the vertical accelerations at the same measurement heights, and the vibration energy attenuated gradually from the shoulder to the toe along the slope; (3) in the short-term tests, the peak accelerations at all measurement points had a linear correlation with the axle load, and oppositely, it showed an approximately linear decrease with the increasing reinforcement pressure; And (4) in the long-term tests, to simulate the heavy haul wagon with a 35 t axle load, the variation in the effective acceleration with loading cycles under reinforcement pressure 100 kPa initially exhibited a decrease and subsequently tended to be stable, which is apparently less than that without reinforcement pressure. Consequently, it was demonstrated that the PRS itself and increasing reinforcement pressure can effectively mitigate the subgrade vibration, and provide an appropriate alternative to improve the dynamic performance of railway subgrade under the moving train loads.

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Evaluation of Critical Dynamic Stress and Accumulative Plastic Strain of an Unbound Granular Material Based on Cyclic Triaxial Tests

Cited by 8 publications

References 63 publications

A Variable-Order Dynamic Constitutive Model for Clay Based on the Fractional Calculus

A Variable-Order Dynamic Constitutive Model for Clay Based on the Fractional Calculus

Pavement Analysis with the Consideration of Unbound Granular Material Nonlinearity

Dynamic Response Characteristics of Railway Subgrade Using a Newly-Developed Prestressed Reinforcement Structure: Case Study of a Model Test

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