A triaxial creep model for coal containing gas and its stability analysis

2009 ◽  
Vol 15 (3) ◽  
pp. 248-251 ◽  
Author(s):  
Guang-zhi Yin ◽  
Deng-ke Wang ◽  
Gun Huang ◽  
Dong-ming Zhang ◽  
Wei-zhong Wang
Keyword(s):  
Stability Analysis ◽  
Creep Model ◽  
Triaxial Creep

Study on Non-Linear Viscous Elastic-Plastic Creep Model of Mica-Quartzose Schist

2012 ◽  
Vol 157-158 ◽  
pp. 622-627 ◽  
Author(s):  
Wen Ling Chen ◽  
Fa Suo Zhao
Keyword(s):  
Viscoelastic Model ◽  
Creep Model ◽  
Model Parameters ◽  
Elastic Plastic ◽  
Creep Curves ◽  
Non Linear ◽  
Triaxial Creep ◽  
Consistency Of The Test ◽  
The Right ◽  
Plastic Creep

Firstly, the creep curves of mica-quartzose schist are obtained through the triaxial creep test, the triaxial creep characteristics are found out by analyzing the creep curves. Secondly, a linear viscoelastic model is established by using model theory, a viscoplastic model is established by using empirical formula, added the above two model, a non–linear viscous elastic-plastic creep model of mica-quartzose schist is obtained. Lastly, the creep model parameters are got by data fitting, the good consistency of the test curves and the theoretical curves show the right and reasonable of the creep model. The non–linear viscous elastic-plastic creep model established can well describe the accelerated creep of mica-quartzose schist.

Stability Analysis of Storage Caverns in Bedded Salt Rock Formation

2013 ◽  
Vol 353-356 ◽  
pp. 1345-1352
Author(s):  
Ming Zhang ◽  
Qiang Yang
Keyword(s):  
Stability Analysis ◽  
Internal Pressure ◽  
Influencing Factor ◽  
Creep Model ◽  
Salt Rock ◽  
Rock Formation ◽  
Long Term Stability ◽  
The Stability ◽  
Salt Caverns

Salt cavern storage is usually in bedded salt rock formation except salt dome, in particular in China. The rocks composing a bedded salt rock formation, e.g., mudstone, rock salt, interlayer, etc., often present viscoelastic-plastic behaviors, which is an important influencing factor of the long-term stability of salt caverns in it. Modelling the rheological behavior with the Druck-Prager creep model, an example of stability analysis of four salt caverns at Jintan Salt Mine of China with the finite element method is elaborated in this paper. The results show that besides the inevitable loss of effective storage room with time due to creep deformation, which decreases evidently with internal pressure but decreases slowly at a certain pressure value, the variation of operating internal pressure in each cavern can cause the change of volumes of other nearby caverns and then affect the stability of all the caverns. The internal pressure difference should be as small as possible during the operation of salt caverns.

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.

Study on triaxial creep behavior and the damage constitutive model of red sandstone containing a single ice-filled flaw

2020 ◽  
pp. 105678952096143
Author(s):  
Yao Bai ◽  
Renliang Shan ◽  
Tianyu Han ◽  
Haoyu Dou ◽  
Zhe Liu
Keyword(s):  
Constitutive Model ◽  
Creep Behavior ◽  
Creep Property ◽  
Creep Model ◽  
Creep Process ◽  
Red Sandstone ◽  
Creep Curves ◽  
Triaxial Creep ◽  
Dip Angle ◽  
Frozen Red Sandstone

The freezing method is widely used in the construction of vertical shafts in water-rich strata. The formed frozen rock wall is often involved in the creep process, and in particular, the creep behavior of frozen fissured rock mass poses a great threat to construction safety. To better understand the creep instability law of ice-filled, fractured red sandstone under freezing and triaxial stress conditions, a series of triaxial creep tests on frozen red sandstone specimens containing a single, pre-existing flaw at −10°C and under a confining pressure of 4 MPa were carried out with a self-developed DRTS-500 subzero rock triaxial testing system. The multistage loading creep curves were obtained, and the evolution laws of deformation and damage for the frozen specimens in the primary (instantaneous), secondary (steady-state) and tertiary (accelerating) phases were analyzed. The nonlinear visco-elastoplastic constitutive model of red sandstone with a single ice-filled flaw was established according to the fractional calculus theory and the Kachanov damage theory. The results show that the initial creep property, unstable creep property and creep failure mode of frozen single-flaw red sandstone are significantly affected by the flaw dip angle. The proposed creep damage model can accurately describe the complete creep curves of frozen red sandstone with a single ice-filled flaw, especially in the unstable creep stage. The influences of the stress level and flaw dip angle on the creep parameters were analyzed, and sensitivity analyses of the characteristic creep parameters were carried out to verify the reliability and rationality of our creep model. This research can be applied to the assessment of collapse, cracking and other long-term failures and hence can be used as a theoretical basis of design in the freezing engineering of coal mine shafts.

Experimental Studies of Creep Characters of Tunnel Lining Concrete

2014 ◽  
Vol 875-877 ◽  
pp. 657-663
Author(s):  
Jian Ren Gao ◽  
Gang Zhang ◽  
An Li Wang ◽  
Sheng Zhang ◽  
Xiao Guang Jin
Keyword(s):  
Stress Level ◽  
Creep Curve ◽  
Experimental Studies ◽  
Creep Model ◽  
Test Results ◽  
Kelvin Model ◽  
Hydraulic Servo ◽  
Creep Characteristic ◽  
Triaxial Creep ◽  
Generalized Kelvin Model

Adopting MTS815 hydraulic servo system, through triaxial compressive deformation and triaxial creep experiment result of tunnel supports, research the stress-strain and creep properties of tunnel supports. Test results show that deformation process of support concrete displays obvious strain softening, instantaneous elastic strain increments with stress level and strain of creep curve appears increased trend with time. Creep curve of concrete drive to a fixed value when stress level is lower and strain rate of concrete more and more small. The generalized Kelvin model of three element and LUBBY2 model are feasible as creep model of concrete support. Based on the relation of creep characteristic curves for rock salt, the creep parameters of generalized Kelvin model and LUBBY2 model are advanced.

scholarly journals The 3D Nonstationary Creep Constitutive Model of Sandstone Based on Fractional Order

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Shuguang Zhang ◽  
Wenbo Liu
Keyword(s):  
Fractional Order ◽  
Creep Test ◽  
Creep Model ◽  
Good Prediction ◽  
Test Machine ◽  
Nonlinear Creep ◽  
Creep Characteristics ◽  
Marquardt Algorithm ◽  
Rock Creep ◽  
Triaxial Creep

Based on nonlinear creep characteristics of rock, triaxial creep tests were conducted on sandstone by using an MTS812.02 test machine. The creep properties of rocks under different conditions were analyzed. Establishing a creep model that describes parameter degradation is necessary to address the deterioration of rock creep parameters over time. A nonstationary Abel pot was constructed on the basis of laws of damage accumulation and deterioration. Then, the nonstationary creep model was established according to fractional order theory. The parameters of the triaxial creep test curve under different confining pressures were identified on the basis of Levenberg–Marquardt algorithm in Hengda coal mine in Fuxin, China. By comparing the model curve with the experimental curve, we found that the nonlinear model not only accurately reflected the creep characteristics of the decay and steady creep stages but also overcame the limitation of traditional creep model, that is, difficulty in describing the accelerated creep. Finally, the influence of fractional order and nonstationary parameters on rock creep was obtained by parameter sensitivity analysis. Overall, the model had high fitting degree as well as good prediction and analysis for 3D creep test data.

Study on Viscoelastic Plastic Damage Model for Mica-Quartzose Schist

2013 ◽  
Vol 300-301 ◽  
pp. 1186-1192 ◽  
Author(s):  
Wen Ling Chen ◽  
Fa Suo Zhao
Keyword(s):  
Damage Model ◽  
Creep Damage ◽  
Damage Variable ◽  
Creep Model ◽  
Creep Process ◽  
Plastic Damage ◽  
Accelerated Creep ◽  
Linear Viscoelastic ◽  
Triaxial Creep ◽  
Plastic Creep

A linear viscoelastic plastic creep model of mica-quartzose schist is established by using the method of establishing combined-linear-component model based on triaxial creep test. The micro-structural changes of mica-quartzose schist during triaxial creep process are observed by using the scanning electron microscope test, based on that, the relation of macro-stress and macro-strain with porosity and damage variable are established through statistical damage theory and simplified mechanical model respectively, the creep damage variable is obtained by further derivation on the basis of above study. The creep damage variable is simplified according to the whole creep process curve, substitutes the simplified creep damage to the estabilished linear viscoelastic plastic creep model of mica-quartzose schist, considering the change of modulus and viscosity during creep process, a viscoelastic plastic damage model of mica-quartzose schist is established. The model parameters are got by segment fitting, the good consistency of the test curves and the fitted curves shows the right and reasonable of the creep model, it also shows that the model can well describe the nonlinear accelerated creep stage. Sensitivity analysis shows that parameter m has greater influence on the accelerated creep deformation than parameter a.

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