scholarly journals Deformation and damage dynamic characteristics of coal–rock materials in deep coal mines

2017 ◽  
Vol 28 (1) ◽  
pp. 58-78 ◽  
Author(s):  
Jiankun Xu ◽  
Rui Zhou ◽  
Dazhao Song ◽  
Nan Li ◽  
Kai Zhang ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Axial Strain ◽  
Failure Process ◽  
Surface Damage ◽  
Damage Mechanism ◽  
Critical Values ◽  
Deformation And Failure ◽  
Rock Materials ◽  
Macroscopic Deformation ◽  
Coal Rock

The deformation and damage characteristics of surrounding rock grow gradually with the increase of mining depth, and the mechanical behavior and damage mechanism of coal–rock materials vary greatly. In order to reveal the deformation and damage dynamic characteristics of coal–rock materials in deep mines, the macroscopic deformation characteristics of coal, rock, and concrete samples under uniaxial compression were studied. The macroscopic deformation amount, velocity, and acceleration of different samples were analyzed. The coal and rock samples exhibit regular dynamic characteristics before they lose stability and fail. The axial strain response of the coal samples changes significantly during the compact and elastic deformation stages. Besides, the relationship between the surface damage and the macroscopic deformation of sample was studied by means of visualization and image processing. The macroscopic deformation index of coal–rock materials changes significantly before and after the destabilization and failure. Based on the deformation and failure dynamic characteristics of coal and rock, the evolution rule of deformation critical values was taken as the deformation and destruction stages, which revealed the dynamic characteristics during the deformation and failure process of coal–rock materials in deep mines. The deformation critical values can be used to realize early warning of deformation and fracture of coal and rock materials in deep mines.

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.

Study on Damage Evolution Mechanism of Concrete under Uniaxial Tension

2012 ◽  
Vol 238 ◽  
pp. 46-50
Author(s):  
Wei Feng Bai ◽  
Ying Cui ◽  
Qian Wang ◽  
Jun Feng Guan ◽  
Jian Wei Zhang
Keyword(s):  
Uniaxial Tension ◽  
Damage Mechanics ◽  
Failure Process ◽  
Damage Model ◽  
Damage Mechanism ◽  
Deformation Characteristics ◽  
Deformation And Failure ◽  
Damage And Failure ◽  
Basic Parameters ◽  
Fundamental Research

The damage and failure mechanism of quasi-brittle materials is the most fundamental research topic in Damage Mechanics. In this paper, the mesoscopic damage mechanism of concrete under uniaxial tension was discussed. The rupture and yield damage modes in meso-scale were introduced as the two basic parameters to define the damage accumulated variable. The results show that the proposed statistical damage model can accurately predict the whole deformation and failure process of concrete under uniaxial tension, including the two-stage deformation characteristics and the size effect.

scholarly journals Research on Supporting Method for High Stressed Soft Rock Roadway in Gentle Dipping Strata of Red Shale

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 423
Author(s):  
Chunde Ma ◽  
Jiaqing Xu ◽  
Guanshuang Tan ◽  
Weibin Xie ◽  
Zhihai Lv
Keyword(s):  
Failure Process ◽  
High Stress ◽  
Soft Rock ◽  
In Situ Stress ◽  
Mechanical Parameters ◽  
Deformation And Failure ◽  
Deep Mine ◽  
Plastic Energy ◽  
Roadway Stability ◽  
Phosphate Mine

Red shale is widely distributed among the deep mine areas of Kaiyang Phosphate Mine, which is the biggest underground phosphate mine of China. Because of the effect of various factors, such as high stress, ground water and so on, trackless transport roadways in deep mine areas were difficult to effectively support for a long time by using traditional supporting design methods. To deal with this problem, some innovative works were carried out in this paper. First, mineral composition and microstructure, anisotropic, hydraulic mechanical properties and other mechanical parameters of red shale were tested in a laboratory to reveal its deformation and failure characteristics from the aspect of lithology. Then, some numerical simulation about the failure process of the roadways in layered red shale strata was implemented to investigate the change regulation of stress and strain in the surrounding rock, according to the real rock mechanical parameters and in-situ stress data. Therefore, based on the composite failure law and existing support problems of red shale roadways, some effective methods and techniques were adopted, especially a kind of new wave-type bolt that was used to relieve rock expansion and plastic energy to prevent concentration of stress and excess deformation. The field experiment shows the superiorities in new techniques have been verified and successfully applied to safeguard roadway stability.

Studied for Mechanism of that Abrasive Water Jet Cutting Metal Materials

2014 ◽  
Vol 513-517 ◽  
pp. 218-222
Author(s):  
Zheng Long Zou ◽  
Xiong Duan ◽  
Chu Wen Guo
Keyword(s):  
Cutting Parameters ◽  
Damage Mechanism ◽  
Water Jet ◽  
Abrasive Water Jet ◽  
Deformation And Failure ◽  
Water Jet Cutting ◽  
Abrasive Water Jet Cutting ◽  
Electron Microscope Analysis ◽  
Metal Materials ◽  
Selection Of

Combining with the electron microscope analysis of the morphology of incision, the mechanism of abrasive water jet cutting metal materials was carried out to explore, for the rational selection of abrasive jet cutting parameters, to extend its application to provide the basis. Study shows that the abrasive water jet cutting metal materials, the material damage mechanism is mainly to yield deformation and failure and shear of grinding damage, grooving formation is mainly caused by falling impact deformation and furrows grinding.

scholarly journals Energy Evolution Law of Marble Failure Process Under Different Confining Pressures Based on Particle Discrete Element Method

2021 ◽  
Vol 8 ◽  
Author(s):  
Yan-Shuang Yang ◽  
Wei Cheng ◽  
Zhan-Rong Zhang ◽  
Hao-Yuan Tian ◽  
Kai-Yue Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Energy Dissipation ◽  
Axial Strain ◽  
Triaxial Compression ◽  
Failure Process ◽  
Rock Failure ◽  
Biaxial Compression ◽  
Energy Evolution ◽  
Confining Pressures ◽  
Energy Dissipated

The energy dissipation usually occurs during rock failure, which can demonstrate the meso failure process of rock in a relatively accurate way. Based on the results of conventional triaxial compression experiments on the Jinping marble, a numerical biaxial compression model was established by PFC2D to observe the development of the micro-cracks and energy evolution during the test, and then the laws of crack propagation, energy dissipation and damage evolution were analyzed. The numerical simulation results indicate that both the crack number and the total energy dissipated during the loading process increase with confining pressures, which is basically consistent with the experiment results. Two damage variables were presented in terms of the density from other researchers’ results and energy dissipation from numerical simulation, respectively. The energy-based damage variable varies with axial strain in the shape of “S,” and approaches one more closely than that based on density at the final failure period. The research in the rock failure from the perspective of energy may further understand the mechanical behavior of rocks.

scholarly journals Experimental study on deformation and failure characteristics of discontinuous prefabricated fractured tuff

2019 ◽  
Vol 16 (5) ◽  
pp. 862-874
Author(s):  
Yang Song ◽  
Heping Wang ◽  
Meng Ren
Keyword(s):  
Shear Failure ◽  
Failure Process ◽  
Dissipated Energy ◽  
Uniaxial Compression Test ◽  
Tensile Shear ◽  
Joint Spacing ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Peak Intensity ◽  
Dip Angle

Abstract To study more fully the characteristic law of deformation and failure of tuff jointed rock mass of prefabricated parallel discontinuous joint test specimens, the uniaxial compression test was used. The stress–strain curve, peak intensity, deformation parameters, energy characteristics, etc., of the rock test specimens were systematically studied under different combinations of joint dip angle and joint spacing. The research found that: (1) during the failure process of tuff, the peak intensity and elastic modulus followed a U-shaped change pattern and the minimum value was reached when α = 60°; (2) the fracture modes of test specimens with different joint dip angles were different. When α = 30° and 45°, failure characteristics were mixed modes of tensile or tensile shear failure. When α = 60°, failure characteristics were shear. At α = 75°, the failure characteristic was tensile shear failure. (3) The absorbed and dissipated energy of the rock increased nonlinearly at each stage of deformation. (4) We quantified rock energy damage through a correlation between dissipated energy and absorbed energy of the rock in the process of energy evolution, and obtained an evolution of the relationship between the dissipated energy ratio, crack dip angle and crack spacing. Based on different fracture distribution methods and according to the strain equivalence principle, the constitutive equation of the pre-peak rock damage was obtained.

Study on the surface damage mechanism of monocrystalline silicon in micro ball-end milling

2019 ◽  
Vol 56 ◽  
pp. 223-234 ◽  
Author(s):  
Minghui Yang ◽  
Fangyu Peng ◽  
Rong Yan ◽  
Ben Deng ◽  
Lin Zhou ◽  
...  
Keyword(s):  
End Milling ◽  
Surface Damage ◽  
Damage Mechanism ◽  
Monocrystalline Silicon ◽  
Ball End Milling
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