scholarly journals A Time-Dependent Creep Constitutive Model of Deep Surrounding Rock under Temperature-Stress Coupling

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xiaofeng Li ◽  
Zhixiang Yin
Keyword(s):  
Creep Deformation ◽  
Test System ◽  
Surrounding Rock ◽  
Creep Model ◽  
Spring Element ◽  
Rock Creep ◽  
Accelerated Creep ◽  
Different Temperatures ◽  
Creep Constitutive Model ◽  
Triaxial Creep Test

In order to study the creep behavior of the surrounding rock of Hengda coal mine in Fuxin under different temperatures, the triaxial creep test of sandstone is carried out by the MTS815.02 test system. The relationship between damage variables and temperature is constructed based on the Weibull distribution of the meso-probability voxel intensity. Aiming at the nonlinear characteristics of rock creep, a nonlinear viscous pot element and a nonlinear spring element are proposed. The two linear viscous pot elements and one linear spring element in the Nishihara model can be replaced separately. Thus, an unsteady parameter creep model is established. The comparison between the Nishihara model curve and the model and the experimental curves in this article has been added to the article. Furthermore, the superiority of this model can be proved. The results show that the established variable-time aging creep model not only can describe the rock attenuation creep and stable creep deformation characteristics but also can make up for the shortcomings of the traditional creep model that cannot describe the accelerated creep characteristics. Moreover, it predicts the development law of creep deformation well. The model is in good agreement with the test curve, which shows the correctness and rationality of the model. It has guiding significance for actual engineering support and prediction of long-term deformation of surrounding rock.

scholarly journals A Time-Dependent Creep Constitutive Model of Deep Surrounding Rock Under Temperature-Stress Coupling

2021 ◽  
Author(s):  
Xiaofeng Li ◽  
Zhixiang Yin
Keyword(s):  
Creep Deformation ◽  
Least Squares Method ◽  
Variable Parameter ◽  
Creep Damage ◽  
Strain Ratio ◽  
Test System ◽  
Surrounding Rock ◽  
Creep Model ◽  
Accelerated Creep ◽  
Triaxial Creep Test

Abstract In order to study the creep behavior of surrounding rock of Hengda coal mine in Fuxin under different temperature, the triaxial creep test of sandstone is carried out by MTS815.02 test system. Based on the Nishihara model, the model creep parameters are denormalized by introducing the relationship among damage variables, time and temperature. The improved variable parameter creep aging model is obtained. The creep parameters are identified by least squares method. The correctness of the creep model is verified by comparing the experimental data with the model curves. The results show that the instantaneous strain to the total strain ratio decreases first and then increases due to the compaction deformation of the internal voids under the initial stress level. The decrease of temperature effectively increases the rock bearing capacity and delays the creep damage time. The established variable-time aging creep model can not only describe the rock attenuation creep and stable creep deformation characteristics, but also makes up for the shortcomings of the traditional creep model that can not describe the accelerated creep characteristics. And it predict the development law of creep deformation well. The model is in good agreement with the test curve, which shows the correctness and rationality of the model. It has guiding significance for actual engineering support and prediction of long-term deformation of surrounding rock.

scholarly journals Experimental Study on the Creep Characteristics of Coal Measures Sandstone under Seepage Action

Processes ◽  
2018 ◽  
Vol 6 (8) ◽  
pp. 110 ◽  
Author(s):  
Ziheng Sha ◽  
Hai Pu ◽  
Ming Li ◽  
Lili Cao ◽  
Ding Liu ◽  
...  
Keyword(s):  
Creep Deformation ◽  
Deformation Rate ◽  
Confining Pressure ◽  
Test System ◽  
Stability Control ◽  
Surrounding Rock ◽  
Natural State ◽  
Saturation State ◽  
Creep Characteristics ◽  
Coal Measures

The seepage action of underground water accelerates the deformation of roadway surrounding rock in deep mines. Therefore, the study of creep characteristics of surrounding rock under seepage action is the basis for the stability control of roadway surrounding rock in deep water-rich areas. In this paper, a seepage-creep coupling test system for complete rock samples was established. Combined with a scanning electron microscopy (SEM) test system, the seepage-creep law of coal measures sandstone and the damage mechanism were revealed. The study results showed that the maximum creep deformation of sandstone under natural and saturation state decreased gradually with the increase of confining pressure, and the maximum creep deformation under saturation state was greater than the corresponding value under natural state when the confining pressure was same. When the confining pressure was constant, the creep deformation, the constant creep deformation rate and the accelerated creep deformation rate of sandstone increased rapidly with the increase of infiltration pressure. With the change of time, the change of permeability parameters went through three cycles; each cycle was divided into two stages, slow change stage and rapid change stage, and the rate of variation increased with the increase of the seepage pressure. Based on the macroscopic and microscopic characteristics of sandstone rupture, the connection between macroscopic and microscopic mechanism on sandstone rupture was established. The results in this paper can provide a theoretical basis for stability control of roadway surrounding rock in water-rich areas.

scholarly journals Nonlinear Viscoelastic-Plastic Creep Model of Rock Based on Fractional Calculus

2022 ◽  
Vol 2022 ◽  
pp. 1-7
Author(s):  
Erjian Wei ◽  
Bin Hu ◽  
Jing Li ◽  
Kai Cui ◽  
Zhen Zhang ◽  
...  
Keyword(s):  
Fractional Calculus ◽  
Fractional Order ◽  
Engineering Application ◽  
Creep Model ◽  
Nonlinear Viscoelastic ◽  
Rock Creep ◽  
Order Change ◽  
Creep Constitutive Model ◽  
Plastic Creep

A rock creep constitutive model is the core content of rock rheological mechanics theory and is of great significance for studying the long-term stability of engineering. Most of the creep models constructed in previous studies have complex types and many parameters. Based on fractional calculus theory, this paper explores the creep curve characteristics of the creep elements with the fractional order change, constructs a nonlinear viscoelastic-plastic creep model of rock based on fractional calculus, and deduces the creep constitutive equation. By using a user-defined function fitting tool of the Origin software and the Levenberg–Marquardt optimization algorithm, the creep test data are fitted and compared. The fitting curve is in good agreement with the experimental data, which shows the rationality and applicability of the proposed nonlinear viscoelastic-plastic creep model. Through sensitivity analysis of the fractional order β2 and viscoelastic coefficient ξ2, the influence of these creep parameters on rock creep is clarified. The research results show that the nonlinear viscoelastic-plastic creep model of rock based on fractional calculus constructed in this paper can well describe the creep characteristics of rock, and this model has certain theoretical significance and engineering application value for long-term engineering stability research.

A Creep-Damage Constitutive Model for Sandstone

2012 ◽  
Vol 170-173 ◽  
pp. 289-294 ◽  
Author(s):  
Wei Wang ◽  
Jun Lv ◽  
Hai Cheng Wang
Keyword(s):  
Constitutive Model ◽  
Creep Test ◽  
Creep Damage ◽  
Creep Model ◽  
Whole Process ◽  
Proposed Model ◽  
Accelerated Creep ◽  
Damage Constitutive Model ◽  
Triaxial Creep ◽  
Triaxial Creep Test

Based on the results obtained by the triaxial creep test, a creep-damage constitutive model for sandstone is presented by using the damage theory and by introducing the concept of “the whole process of damage” into Burgers creep model. The parameters of the model are determined by fitting the creep test data. The result shows that the proposed model can not only describe efficiently the variation of decay and steady creep under relatively low stress condition, but also give a satisfied representation of damage behavior in accelerated creep stage.

scholarly journals A non-linear creep constitutive model for salt rock based on fractional derivatives

2019 ◽  
Vol 23 (Suppl. 3) ◽  
pp. 773-779 ◽  
Author(s):  
Jie Chen ◽  
Dan Lu ◽  
Fei Wu ◽  
Jinyang Fan ◽  
Wei Liu
Keyword(s):  
Constitutive Model ◽  
Creep Property ◽  
Salt Rock ◽  
Whole Process ◽  
Rock Creep ◽  
Non Linear ◽  
Accelerated Creep ◽  
Deep Underground ◽  
Abel Dashpot ◽  
Creep Constitutive Model

The creep property of the salt rock is an important determinant of deep underground repository of energy storage for long-term operatio. Starting from fractional derivative, this paper proposes a new concept of super Abel dashpot based on Abel dashpot. According to the Nishihara model, the non-linear element of super Abel dashpot is introduced, and a new salt rock creep constitutive model is established. The theoretical analytic solution of this model is then deduced. Fitting analysis of the experimental data indicates that the model can well reflect the whole-process creep curve, especially the non-linear accelerated creep stage.

scholarly journals Viscoelastoplastic Displacement Solution for Deep Buried Circular Tunnel Based on a Fractional Derivative Creep Model

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Yi-Hang Gao ◽  
Zhou Zhou ◽  
Hang Zhang ◽  
Shuang Jin ◽  
Wen Yang ◽  
...  
Keyword(s):  
Analytical Solution ◽  
Creep Deformation ◽  
Soft Rock ◽  
Creep Model ◽  
Circular Tunnel ◽  
Rock Stratum ◽  
Model Combining ◽  
Accelerated Creep ◽  
Abel Dashpot ◽  
Viscous Element

Time-dependent deformation of surrounding rock is a common phenomenon for tunnels situated in soft rock stratum or hard rock stratum with high geo-stress. To describe this phenomenon, a creep model combining the Abel dashpot and a non-Newton viscous element was adopted, and the analytical solution about the viscoelastoplastic deformation for circular tunnel was obtained based on this creep model. Then, the auxiliary tunnel of Jinping II hydropower station was taken as an example to reveal the influence of creep parameters on the creep deformation. The research shows that (1) the creep model can well describe the whole creep stage of rocks, that is, the decay, constant, and accelerated creep stages, (2) the creep deformation has a positive relation with the value of fractional order of Abel dashpot and the order of the non-Newton viscous element, and (3) the creep curves between test results and analytical solutions are well consistent with each other, which demonstrate the validity of the analytical solution.

Viscoplastic Behavior of Hypo-Eutectic Sn3.0Ag0.5Cu Pb-Free Alloy Under Creep Loading Conditions

2007 ◽  
Author(s):  
Gayatri Cuddalorepatta ◽  
Abhijit Dasgupta
Keyword(s):  
Primary Creep ◽  
Test System ◽  
Creep Model ◽  
Secondary Creep ◽  
Sac305 Solder ◽  
Different Temperatures ◽  
Creep Measurements ◽  
Creep Models ◽  
Future Work ◽  
Creep Loading

The time-dependent viscoplastic behavior of hypoeutectic Sn3.0Ag0.5Cu (SAC305) solder is presented. Mechanical shear tests are conducted at room and high temperatures, using a custom-built thermo-mechanical-microscale (TMM) test system. This test system uses a modified Iosipescu shear specimen with a 180 microns wide solder joint. Creep deformation is measured at constant stress levels between 3 MPa to 20 MPa, at different temperatures. The creep results are fit using Garofalo’s secondary creep model and a generalized exponential primary creep model. Secondary creep measurements from the current work are higher than those reported in literature. Discrepancies in the curve fits based on the chosen continuum creep models are discussed. Possible sources of the discrepancies are discussed. In future work the primary and secondary creep constants measured from this work will be used in viscoplastic finite element models to compare with stress relaxation behavior measured earlier on the TMM specimens at various temperatures and strain levels [1].

scholarly journals Study on Time-Dependent Behavior of Granite and the Creep Model Based on Fractional Derivative Approach Considering Temperature

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Zhilei He ◽  
Zhende Zhu ◽  
Nan Wu ◽  
Zhen Wang ◽  
Shi Cheng
Keyword(s):  
Fractional Derivative ◽  
Creep Property ◽  
Experimental Studies ◽  
Sensitivity Study ◽  
Creep Model ◽  
Three Gorges ◽  
Dependent Behavior ◽  
Mineral Components ◽  
Different Temperatures ◽  
Creep Constitutive Model

Based on mineral components and the creep experimental studies of Three Gorges granite and Beishan granite from different regions of China at various temperatures, the strength and creep property of two types of granites are compared and analyzed. Considering the damage evolution process, a new creep constitutive model is proposed to describe the creep property of granite at different temperatures based on fractional derivative. The parameters of the new creep model are determined on the basis of the experimental results of the two granites. In addition, a sensitivity study is carried out, showing effects of stress level, fractional derivative order, and the exponentm. The results indicate that the proposed creep model can describe the three creep stages of granite at different temperatures and contribute to further research on the creep property of granite.

scholarly journals Effect of Rubberized Bitumen Blending Methods on Permanent Deformation of SMA Rubberized Asphalt Mixtures

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Herda Yati Katman ◽  
Mohd Rasdan Ibrahim ◽  
Mohamed Rehan Karim ◽  
Suhana Koting ◽  
Nuha Salim Mashaan
Keyword(s):  
Creep Behaviour ◽  
Permanent Deformation ◽  
Asphalt Mixtures ◽  
Creep Model ◽  
Materials Testing ◽  
Wet Process ◽  
Test Conditions ◽  
Dynamic Creep ◽  
Different Temperatures ◽  
Stone Mastic Asphalt

This study aims at comparing the permanent deformation of Stone Mastic Asphalt (SMA) rubberized asphalt mixtures produced by the wet process. In this study, rubberized binders were prepared using two different blending methods, namely, continuous blend and terminal blend. To study the creep behaviour of control and rubberized asphalt mixtures, the dynamic creep test was performed using Universal Materials Testing Apparatus (UMATTA) at different temperatures and stress levels. Zhou three-stage creep model was utilized to evaluate the deformation characteristics of the mixtures. In all test conditions, the highest resistance to permanent deformation is showed by the rubberized mixtures produced with continuous blend binders. This study also reveals that the permanent deformation of rubberized mixtures cannot be predicted based on the characteristics of the rubberized binders.

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