scholarly journals Study on Damage Constitutive Model of High-Concentration Cemented Backfill in Coal Mine

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Baogui Yang ◽  
Haigang Yang
Keyword(s):  
Constitutive Model ◽  
Coal Mine ◽  
Damage Evolution ◽  
Triaxial Compression ◽  
Failure Process ◽  
Model Parameters ◽  
High Concentration ◽  
Deformation And Failure ◽  
Cemented Backfill ◽  
Damage Constitutive Model

In order to construct the damage constitutive model (DCM) of high-concentration cemented backfill (HCCB) in coal mine, the generalized Hoek-Brown strength criterion was used as the failure criterion. For the difference of theoretical derivation of constitutive relation, a new DCM based on residual strength was proposed. Combined with the conventional triaxial compression test, the correctness and rationality of the DCM were verified. The damage evolution characteristics of HCCB were analyzed, and the physical meaning of model parameters was clarified. The results show that (a) the theoretical curves of stress-strain relation are in good agreement with its experimental curves, which means DCM can simulate the deformation and failure process of HCCB. (b) The damage evolution curve of HCCB is S -shaped. To some extent, the confining pressure can inhibit the development of damage. (c) The parameter F 0 reflects the position of the peak point of the DCM, and parameter n is the slope of the straight line segment in the postpeak strain softening stage, which are, respectively, used to characterize the strength level and brittleness of HCCB. The establishment of DCM of HCCB is helpful to reveal its deformation and failure mechanism and provides theoretical basis for its strength design.

scholarly journals Study of Damage Constitutive Model of Brittle Rocks considering Stress Dropping Characteristics

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Fei Li ◽  
Shuang You ◽  
Hongguang Ji ◽  
Hao Wang
Keyword(s):  
Constitutive Model ◽  
Triaxial Compression ◽  
Strain Curve ◽  
Brittle Rock ◽  
Model Parameters ◽  
Deformation And Failure ◽  
Brittle Rocks ◽  
Whole Process ◽  
Confining Pressures ◽  
Damage Constitutive Model

Deep brittle rock exhibits characteristics of rapid stress dropping rate and large stress dropping degree after peak failure. To simulate the whole process of deformation and failure of the deep brittle rock under load, the Lemaitre strain equivalent theory is modified to make the damaged part of the rock has residual stress. Based on the damage constitutive model considering residual strength characteristics, a correction factor reflecting stress dropping rate is added, the Weibull distribution is used to describe the inhomogeneity of rock materials, and Drucker–Prager criterion is used to quantitatively describe the influence of stress on damage; a damage constitutive model of deep brittle rock considering stress dropping characteristics is established. According to the geometric features of the rock stress-strain curve, the theoretical expressions of model parameters are derived. To verify the rationality of the model, triaxial compression experiments of deep brittle rock under different confining pressures are conducted. And the influence of model parameters on rock mechanical behaviour is analysed. The results show that the model reflects the stress dropping characteristics of deep brittle rock and the theoretical curve is in good agreement with the experimental results, which indicates that the proposed constitutive model is scientific and feasible.

scholarly journals Study on Damage Constitutive Model of Rock under Freeze-Thaw-Confining Pressure-Acid Erosion

2021 ◽  
Vol 11 (20) ◽  
pp. 9431
Author(s):  
Youliang Chen ◽  
Peng Xiao ◽  
Xi Du ◽  
Suran Wang ◽  
Tomas Manuel Fernandez-Steeger ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Model Parameters ◽  
Theoretical Derivation ◽  
Freeze Thaw ◽  
Peak Point ◽  
Damage Constitutive Model

Aiming at the acid-etched freeze-thaw rock for geotechnical engineering in cold regions, chemical damage variables, freeze-thaw damage variables, and force damage variables were introduced to define the degree of degradation of rock materials, the law of damage evolution, the total damage variable of acid-corroded rock under the coupling action of freeze-thaw and confining pressure was deduced. The continuous damage mechanics theory was adopted to derive the damage evolution equation and constitutive model of acid-eroded rock under the coupling action of freeze-thaw and confining pressure. The theoretical derivation method was used to obtain the required model parameter expressions. Finally, the model’s rationality and accuracy were verified by the triaxial compression test data of frozen-thawed rocks. Comparing the test curve’s peak point with the peak point of the model theoretical curve, the results show that the two are in suitable agreement. The damage constitutive model can better reflect the stress-strain peak characteristics of rock during triaxial compression, verifying the rationality and reliability of the model and the method for determining the model parameters. The model extends the damage model of rock under the coupling action of freeze-thaw and confining pressure in the chemical environment and further reveals the damage mechanism and failure law of acid-corroded rock under the coupling action of freeze-thaw and confining pressure.

Constitutive model to simulate full deformation and failure process for rocks considering initial compression and residual strength behaviors

2019 ◽  
Vol 56 (5) ◽  
pp. 649-661 ◽  
Author(s):  
Wengui Cao ◽  
Xin Tan ◽  
Chao Zhang ◽  
Min He
Keyword(s):  
Constitutive Model ◽  
Residual Strength ◽  
Triaxial Compression ◽  
Failure Process ◽  
Deformation Model ◽  
Good Prediction ◽  
Compression Tests ◽  
Deformation And Failure ◽  
Macroscopic Deformation ◽  
Triaxial Compression Tests

A constitutive model with capacity to simulate the full deformation and failure process for rocks considering initial compression and residual strength behaviors is discussed in this paper. The rock was assumed to consist of the initial voids portion and the solid skeleton portion. The full deformation model of rocks can be established by the consideration of the macroscopic deformation of rocks and the microscopic deformations of the two different portions based on the statistical damage theory. Comparisons between the experimental data from triaxial compression tests and calculated results show that the proposed constitutive model provided a good prediction of the full deformation and failure process, including the effects of initial void compression, stiffness degradation, strain hardening–softening, and residual strength.

Statistical damage model with strain softening and hardening for rocks under the influence of voids and volume changes

2010 ◽  
Vol 47 (8) ◽  
pp. 857-871 ◽  
Author(s):  
Wen-Gui Cao ◽  
Heng Zhao ◽  
Xiang Li ◽  
Yong-Jie Zhang
Keyword(s):  
Constitutive Model ◽  
Strain Softening ◽  
Triaxial Compression ◽  
Damage Model ◽  
Damage Threshold ◽  
Model Parameters ◽  
Volume Changes ◽  
Conventional Triaxial Compression ◽  
Damage Constitutive Model ◽  
Statistical Damage

With regards to the composition of natural rocks including voids or pores, deformation behavior is strongly affected by variation in porosity. By using a statistical damage-based approach, the characteristics of strain softening and hardening under the influence of voids and volume changes are investigated in the present paper. Suppose that a rock consists of three parts: voids, a damaged part, and an undamaged part. The effects of voids and volume changes on rock behavior are first analyzed through determination of the porosity and an associated damage model is then developed. Later, a statistical evolution equation describing the influence of the damage threshold on the propagation condition of rock damage is formulated based on measurement of the mesoscopic element strength. A statistical damage constitutive model reflecting strain softening and hardening behavior for rocks loaded in conventional triaxial compression is further developed and a corresponding method for determining the model parameters is also provided. Theoretical results of this proposed model are then compared with those observed experimentally. Finally, several aspects of the present constitutive model, which affect the relevant behavior of rocks, are particularly discussed.

Damage Theoretical Analysis of 2.5D C/SiC Composites under Tensile and Shear Loading

2010 ◽  
Vol 150-151 ◽  
pp. 330-333
Author(s):  
Yan Jun Chang ◽  
Ke Shi Zhang ◽  
Gui Qiong Jiao ◽  
Jian Yun Chen
Keyword(s):  
Constitutive Model ◽  
Damage Evolution ◽  
Yield Function ◽  
Shear Loading ◽  
Isotropic Hardening ◽  
Shear Tests ◽  
Energy Equivalence ◽  
Damage Constitutive Model ◽  
Sic Composites ◽  
Nonlinear Hardening

An anisotropic damage constitutive model is developed to describe the damage behavior of C/SiC composites. Different kinematic and isotropic hardening functions were employed in damage yield function to describe accurately the damage nonlinear hardening. The damage variable is defined by the principle of energy equivalence. The degradation of stiffness and the unrecoverable deformation induced by micro-crack propagation were considered in this model. The constants of constitutive model are identified and the damage evolution processes under tensile and shear loading. Uniaxial tension and shear tests have been used to valid the constitutive model to C/SiC composites.

A statistical damage constitutive model considering whole joint shear deformation

2020 ◽  
Vol 29 (6) ◽  
pp. 988-1008 ◽  
Author(s):  
Shijie Xie ◽  
Hang Lin ◽  
Yixian Wang ◽  
Yifan Chen ◽  
Wei Xiong ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Damage Evolution ◽  
Shear Stiffness ◽  
Rock Joints ◽  
Residual Phase ◽  
Proposed Model ◽  
Damage Constitutive Model ◽  
Damage Theory ◽  
Joint Shear ◽  
Statistical Damage

The whole shear deformation of rock joints significantly affects the long-term behavior and safety of engineering projects. In this paper, a new damage constitutive model related to the Weibull distribution and statistical damage theory is proposed. This model considers the shear stiffness degradation, post-peak softening, and residual phase of rock joints in the whole shearing process. Main works include the three following aspects: First, the phase of initial damage is determined on the assumption that the joint shear failure is regarded as a result of damage evolution, according to the typical joint shear curve and the three-parameter Weibull distribution. Then, a statistical damage evolution model for the whole joint shearing process is introduced to make this model be capable of describing the residual phase of rock joints. Finally, a statistical constitutive model for the whole joint shearing process is proposed by statistical damage theory, and the calculated results of the models are compared to the experimental results. The results indicate that the proposed model shows a good agreement with the experimental examples, and the proposed model can distinctly reflect the effects of residual stress, peak stress, and shear stiffness. In addition, the model parameters can be mathematically confirmed and have distinct physical meanings.

scholarly journals A Thermal Damage Constitutive Model for Oil Shale Based on Weibull Statistical Theory

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Guijie Zhao ◽  
Chen Chen ◽  
Huan Yan
Keyword(s):  
High Temperature ◽  
Constitutive Model ◽  
Oil Shale ◽  
Thermal Damage ◽  
Triaxial Compression ◽  
Strain Curve ◽  
Practical Significance ◽  
Compression Tests ◽  
Different Temperatures ◽  
Damage Constitutive Model

In this work, we first studied the thermal damage to typical rocks, assuming that the strength of thermally damaged rock microelements obeys a Weibull distribution and considering the influence of temperature on rock mechanical parameters; under the condition that microelement failure conforms to the Drucker–Prager criterion, the statistical thermal damage constitutive model of rocks after high-temperature exposure was established. On this basis, conventional triaxial compression tests were carried out on oil shale specimens heated to different temperatures, and according to the results of these tests, the relationship between the temperature and parameters in the statistical thermal damage constitutive model was determined, and the thermal damage constitutive model for oil shale was established. The results show that the thermal damage in oil shale increases with the increase of temperature; the damage variable is largest at 700°C, reaching 0.636; from room temperature to 700°C, the elastic modulus and Poisson’s ratio decrease by 62.66% and 64.57%, respectively; the theoretical stress-strain curve obtained from the model is in good agreement with the measured curves; the maximum difference between the two curves before peak strength is only 5 × 10−4; the model accurately reflects the deformation characteristics of oil shale at high temperature. The research results are of practical significance to the underground in situ thermal processing of oil shale.

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