Analysis and numerical calculation of a coupled creep and strain-softening model for soft rock tunnels

Jianjun, Zhang; Yao, Baicong; Ao, Yunhe; Jin, Chunzhe; Sun, Chao

doi:10.1371/journal.pone.0256243

Cited by 8 publications

(4 citation statements)

References 35 publications

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“…Zhou et al [ 21 ] proposed a creep damage constitutive model based on time-fractional derivatives by replacing Newtonian dampers in the classical Nishihara model. Zhang et al [ 22 ] proposed a Nonlinear Burgers Strain Softening (NBSS) model and a numerical calculation method to describe the plastic zone and deformation law for the surrounding rock. Di et al [ 23 ] put forward a fractional viscous-elastic-plastic model, showing that both creep and recovery curves follow a power-law model.…”

Section: Introductionmentioning

confidence: 99%

A new shear creep damage model for rock masses after considering initial damage

Wang

et al. 2023

PLoS ONE

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For a long time, one of the important safety problems in open-pit mines is the stability of a large number of high slopes with gently inclined soft interlayer. Rock masses formed after long geological processes generally have some initial damage. Mining works also cause varying degrees of disturbance and damage to rock masses in the mining area during the mining process. This phenomenon means that accurate characterization of the time-dependent creep damage for rock masses under shear load is necessary. The damage variable D is defined based on the spatial and temporal evolution laws of shear modulus and initial level of damage for the rock mass. In addition, a coupling damage equation between the initial damage of the rock mass and shear creep damage is established based on Lemaitre’s strain equivalence assumption. Kachanov’s damage theory is also incorporated to describe the entire process of time-dependent creep damage evolution for rock masses. A creep damage constitutive model that can reasonably reflect the actual mechanical properties of rock masses under multi-stage shear creep loading conditions is established. This takes into account multi-stage shear creep loading conditions, instantaneous creep damage during the shear load phase, staged creep damage and factors influencing the initial damage of rock masses. The reasonableness, reliability and applicability of this model are verified by comparing the results of the multi-stage shear creep test with calculated values from the proposed model. As opposed to the traditional creep damage model, the shear creep model established in this present study takes into account the initial damage of rock masses and can describe the multi-stage shear creep damage characteristics of rock masses more convincingly.

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Section: Introductionmentioning

confidence: 99%

A new shear creep damage model for rock masses after considering initial damage

Wang

et al. 2023

PLoS ONE

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“…Zhu et al [27] proposed a new nonlinear creep constitutive model by introducing a damage variable into the viscoplastic element to accurately describe the whole creep process for frozen sand with different dry densities and grain size distributions under different shear stress levels and temperatures. Analogously, to capture the deformation behavior of various geotechnical materials under different mechanical states, authors [28][29][30][31][32][33] constructed a series of significant constitutive models suitable for describing the accumulative deformation of geotechnical materials under static loading. However, element models used to depict the deformation characteristics of geotechnical materials under dynamic loads are comparatively few, though there are some research results in the literature.…”

Section: Introductionmentioning

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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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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“…Under the long-term action of in-situ stress, the rock will undergo creep deformation, and water can deteriorate the mechanical properties of rock and increase the creep deformation of the rock [1][2][3][4]. The classical Nishihara model can describe the first two stages of rock creep deformation well [5,6], but cannot reflect the accelerated creep characteristics of rock and the influence of other factors on rock creep characteristics.…”

Section: Introductionmentioning

confidence: 99%

Improved Nishihara model considering the effect of moisture content on the whole shear creep process of shale

Wei

et al. 2022

Preprint

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The moisture content is closely related to the shear creep deformation behavior of soft rock, and the linear creep deformation behavior of soft rock can be described by the classical Nishihara model. However, the classical Nishihara model cannot describe the deformation characteristics of the whole process of shear creep including nonlinear deformation of rocks under the influence of moisture content. In this study, we presented an improved Nishihara model that connected a strain-triggered nonlinear dashpot in series on the classical Nishihara model to describe the whole process of rock creep, and a damage factor was proposed to reflect the effect of moisture content on the rock creep characteristics. The damage factors and related model parameters were determined from results of the shear creep tests, which were performed under four moisture conditions (0%, 0.46%, 0.87%, and 1.24%). The comparisons between model predictions and experimental results show that the improved creep constitutive model proposed here can not only describe the whole creep process well, but also reveal the influences of the moisture content on the creep behavior of rock, which demonstrate its accuracy and usefulness.

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Analysis and numerical calculation of a coupled creep and strain-softening model for soft rock tunnels

Cited by 8 publications

References 35 publications

A new shear creep damage model for rock masses after considering initial damage

A new shear creep damage model for rock masses after considering initial damage

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

Improved Nishihara model considering the effect of moisture content on the whole shear creep process of shale

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