A fractional elasto-viscoplastic model for describing creep behavior of soft soil

Zhou, Fengxi; Wang, Li-ye; Liu, Hongbo

doi:10.1007/s11440-020-01008-5

Cited by 30 publications

(10 citation statements)

References 31 publications

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“…Secondary compression in soils is usually represented via rheological models [43][44][45][46][47][48][49][50] or phenomenological relations between strain, stress, and time [51][52][53][54] . Among them, Bjerrum 51 proposed a phenomenological model via a set of parallel straight lines on the void ratio-logarithm of effective vertical stress plane, where each line represents a certain duration of sustained loading.…”

Section: Introductionmentioning

confidence: 99%

Time scales in the primary and secondary compression of soils

Liu

Borja

2022

Num Anal Meth Geomechanics

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The last several decades have seen a surge of papers dealing with analytical and semi‐analytical solutions to the problem of one‐dimensional consolidation of soils. But rarely has any of these contributions focused on the time scales arising from combined primary and secondary compression. Primary compression has always been attributed to the dissipation of excess pore pressure as fluid is expelled from the soil skeleton to the drainage boundaries. However, there have been several schools of thought when it comes to the process governing the secondary compression. In this paper, we attribute the secondary compression to any of the following processes occurring either individually or in combination: (a) rate‐dependent (viscoplastic) constitutive response of the soil skeleton; (b) existence of a secondary pore scale system that expels fluid from the smaller‐scale pores to the larger‐scale pores; and (c) delayed compression due to creep following Bjerrum's concept of secondary consolidation. Contributions of the present work include closed‐form analytical solutions to the problem of combined primary and secondary compression of soils in one dimension, as well as a quantitative analysis of the time scales involved in such coupled hydromechanical processes.

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Section: Introductionmentioning

confidence: 99%

Time scales in the primary and secondary compression of soils

Liu

Borja

2022

Num Anal Meth Geomechanics

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“…In mathematical analysis, a fractional derivative is a derivative of any arbitrary order, real or complex, which first appeared in the 1690s 49 . For the reason of simple mathematical form, 50,51 the definition of fractional derivative from Caputo 52 and Caputo and Mainardi 53 was presented in this study. At the interval

t\epsilon [ {a,b} ]

, the left and right Caputo fractional derivatives of a function of order

\alpha (\alpha &gt; 0)

, denoted by

{}_a^CD_t^\alpha f( t )

and

{}_t^CD_b^\alpha f( t )

, respectively, are

\begin{equation} a^CD_t^\alpha f\left( t \right) = \left\{ \def\eqcellsep{&}\begin{array}{@{}*{1}{c}@{}} \displaystyle{\frac{1}{{{{\Gamma}}\left( {n - \alpha } \right)}}\mathop \int_a^t \displaystyle\frac{{{f^{\left( n \right)}}\left( \tau \right)}}{{{{\left( {t - \tau } \right)}^{\alpha + 1 - n}}}}d\tau , n - 1 &lt; \alpha &lt; n}\\[18pt] \displaystyle{\frac{{{d^n}}}{{d{t^n}}}f\left( t \right), \alpha = n} \end{array} \right.

…”

Section: Review Of Pd Theory and Fractional Derivativementioning

confidence: 99%

The peridynamic Drucker‐Prager plastic model with fractional order derivative for the numerical simulation of tunnel excavation

Zhang

Zhou

2022

Num Anal Meth Geomechanics

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In this study, the peridynamic Drucker-Prager plastic model with fractional order derivative is proposed to investigate the plastic behavior of surrounding rocks around tunnels, in which the Caputo fractional derivative is employed due to its mathematical simplicity. Instead of utilizing just one parameter for the typical nonassociated flow rule, such as dilation angle, multiple parameters, such as fractional order and interval of fractional derivative, are used to specify the direction of plastic deformation, and the fractional derivative based-typical flow rule is proposed. As a result, compared with the traditional peridynamic Drucker-Prager plastic model, the proposed method is a more generalized model including the typical nonassociated flow rule. Besides, based on the PD force density, the strategy of exertion of initial stress is proposed to simulate in-situ stress in rocks. Taking a block subjected to compression as an example, the impacts of various factors, such as fractional order and interval of fractional derivative, are investigated. A numerical simulation of tunnel excavation in rocks is carried out and the numerical results obtained by the proposed method are verified by comparing with FEM results.

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“…In terms of the creep test, the research object covers a wide range, such as coarse-grained (Hou et al, 2018), marine sediment (Huang et al, 2020), and frozen (Li et al, 2017) soils. Given its high water content and compressibility, soft soil has an obvious creep characteristic (Zhou et al, 2021). Many studies have been conducted on the creep characteristics of soft soil.…”

Section: Introductionmentioning

confidence: 99%

Soil-Water Characteristics and Creep Deformation of Unsaturated Expansive Subgrade Soil: Experimental Test and Simulation

Yao

Xiao

et al. 2021

Front. Earth Sci.

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The creep deformation of expansive soil has been considered as a vital threat to the safety in engineering construction because it may cause serious slope diseases in geological engineering. Meanwhile, since expansive soil usually remains in unsaturated state, its mechanical property is significantly affected by the seasonal environment. Therefore, the nonlinear deformation of expansive soil has received increasing attention, especially the humidity-dependent creep properties. This study focused on the stability of the unsaturated expansive soil subgrade considering rainfall and the creep behavior. Pressure plate extractor and direct shear tests were performed to investigate the hydro-mechanical and creep characteristics of the unsaturated expansive soil. Both the Van-Genuchten and Burgers models were applied to analyze the test results and inserted into the numerical model of the slope under rainfall infiltration. Results show that the compaction degree and the stress state was closely related to the water holding capacity of the expansive soil. The nonlinearity of the creep behavior became increasingly obvious with the increase of time and the stress level. The safety factor of the slope decreased as the rainfall time increased, and the most dangerous slide of the slope moved toward the foot of the slope. Considering the long-term creep process, there was a period of rapid growth in horizontal displacement that is detrimental to the stability of the slope. Besides, the rainfall infiltration could accelerate the slope failure before and after this creep process.

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A fractional elasto-viscoplastic model for describing creep behavior of soft soil

Cited by 30 publications

References 31 publications

Time scales in the primary and secondary compression of soils

Time scales in the primary and secondary compression of soils

The peridynamic Drucker‐Prager plastic model with fractional order derivative for the numerical simulation of tunnel excavation

Soil-Water Characteristics and Creep Deformation of Unsaturated Expansive Subgrade Soil: Experimental Test and Simulation

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