scholarly journals Towards the Understanding of Damage Mechanism of Cemented Tailings Backfill

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Haijun Wang
Keyword(s):  
Damage Evolution ◽  
Quadratic Function ◽  
Peak Stress ◽  
Damage Mechanism ◽  
Curing Temperature ◽  
Underground Mines ◽  
Fine Tailings ◽  
Successful Design ◽  
Damage Constitutive Model ◽  
Curing Age

Recent studies have shown that the damage characteristics of cemented tailings backfill (CTB) are influenced significantly by the variation of cement-tailings ratio, while the effects of other influencing factors remain unanswered. The CTB damage constitutive model, which takes the corrected coefficient of damage variable into consideration, and peak toughness are introduced to investigate the effects of fine tailings contents, curing ages, curing temperatures, and water-to-cement ratios ( w / c ) on the damage evolution laws, damage ( D P ), and specific energy ( G P ) at peak stress point of CTB. The results show that appropriate content of fine tailings could improve the compressive strength of CTB and reduce its damage evolution speed and D P . The damage growth rate of CTB decreases with curing age in early curing period and increases with higher curing temperature and w / c . D P of CTB takes on a descending trend with higher w / c and fine tailings content but shows an increase with curing age. There exists no significant relationship between D P and curing temperature. G P of CTB increases with curing age and higher curing temperature with a quadratic function but is on a decline with increases of fine tailings content and w / c with logarithmic and exponential function, respectively. The results obtained from our study have important application to the successful design of backfill structures in underground mines.

Thermo-mechanical coupling damage constitutive model of rock based on the Hoek–Brown strength criterion

2017 ◽  
Vol 27 (8) ◽  
pp. 1213-1230 ◽  
Author(s):  
Xiaoli Xu ◽  
Feng Gao ◽  
Zhizhen Zhang
Keyword(s):  
Constitutive Model ◽  
Damage Evolution ◽  
Mechanical Response ◽  
Peak Stress ◽  
Strength Criterion ◽  
Confining Pressure ◽  
Stress Strain ◽  
Mechanical Coupling ◽  
Damage Stability ◽  
Damage Constitutive Model

Studying the thermal damage constitutive model of rock using statistical theory can better reflect the damage evolution process and the stress–strain relationship of rock under temperature and loading, which is one of the key problems especially in deep rock mechanics. The thermal-mechanical coupling damage constitutive model of rock is established using the Hoek–Brown strength criterion, based on the Weibull distribution and the continuous damage theory. The rationality of the model is also verified by experiments. The main conclusions are as follows. The stress–strain curves of rock can be divided into four stages according to the damage evolution characteristics, including the non-damage of loading, damage stability expansion, damage intensification expansion, and damage stability expansion to saturation, and the method of determining the demarcation points of each stage is given clearly. The initial damage point of the rock is about 25% of the peak stress, the damage value is about 0.3 when the rock reaches the peak stress and about 0.6 when reaches the residual stress. Both the damage value and the strain energy release rate of the rock corresponding to the peak stress show exponential growth with the increase in confining pressure. The maximum damage evolution rate of the rock shows exponential decay as the confining pressure rises, indicating that the confining pressure can delay the development of cumulative damage. The modified damage constitutive model considering compaction coefficient is in good agreement with the test curves in the stage of compaction, linear elasticity, yield, and pre-peak strength. It is hoped that through the research of this paper, it can provide references for studying the macroscopic mechanical response from the damage propagation characteristics of the rock in the future.

Effects of Cyclic Stress on the Mechanical Properties of Cultured Collagen Fascicles from the Rabbit Patellar Tendon

2003 ◽  
Vol 125 (6) ◽  
pp. 893-901 ◽  
Author(s):  
Ei Yamamoto ◽  
Susumu Tokura ◽  
Kozaburo Hayashi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Patellar Tendon ◽  
Control Level ◽  
Quadratic Function ◽  
Peak Stress ◽  
Cyclic Stress ◽  
Original Strength

Effects of cyclic stress on the mechanical properties of collagen fascicles were studied by in vitro tissue culture experiments. Collagen fascicles (approximately 300 μm in diameter) obtained from the rabbit patellar tendon were applied cyclic load at 4 Hz for one hour per day during culture period for one or two weeks, and then their mechanical properties were determined using a micro-tensile tester. There was a statistically significant correlation between tensile strength and applied peak stress in the range of 0 to 5 MPa, and the relation was expressed by a quadratic function. The maximum strength (19.4 MPa) was obtained at the applied peak stress of 1.8 MPa. The tensile strength of fascicles were within a range of control values, if they were cultured under peak stresses between 1.1 and 2.6 MPa. Similar results were also observed in the tangent modulus, which was maintained at control level under applied peak stresses between 0.9 and 2.8 MPa. The stress of 0.9 to 1.1 MPa is equivalent to approximately 40% of the in vivo peak stress which is developed in the intact rabbit patellar tendon by running, whereas that of 2.6 to 2.8 MPa corresponds to approximately 120% of the in vivo peak stress. Therefore, the fascicles cultured under applied peak stresses of lower than 40% and higher than 120% of the in vivo peak stress do not keep the original strength and modulus. These results indicate that the mechanical properties of cultured collagen fascicles strongly depend upon the magnitude of the stress applied during culture, which are similar to our previous results observed in stress-shielded and overstressed patellar tendons in vivo.

Damage Mechanism Research of Yushu Airport Road Landslide No.3 Base on Elastoplastic Damage Constitutive Model

2015 ◽  
Vol 744-746 ◽  
pp. 464-469
Author(s):  
Hong Gang Wu ◽  
Tao Yang ◽  
Xiao Yun Chen ◽  
Hui Min Ma ◽  
Hong Li Zhang ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Damage Mechanism ◽  
Earthquake Triggering ◽  
Triggering Mechanism ◽  
Finite Element Program ◽  
Plastic Damage ◽  
Mechanism Research ◽  
Element Program ◽  
Damage Constitutive Model ◽  
Stability Of Slope

Due to the earthquake of Yushu in April 14, 2010, Airport Road landslide No.3 deformed cracking, resulting in lower stability of slope, triggering landslides and other diseases. Selecting the section 2-2 (mileage K823 + 809) of Airport Road landslide No.3 as the calculation section, we use the ABAQUS finite element program to establish landslide numerical mode. The slip mass of landslide was simulated by the elastic-plastic damage constitutive model, and the bedrock was analyzed as Mohr - Coulomb constitutive model. Landslide No3 is analyzed for example, and showed that earthquake triggering mechanism elastplastic damage constitutive model can describe the landslide very well.

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 Mechanical Characteristics of Cement-Based Grouting Material in High-Geothermal Tunnel

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1572 ◽  
Author(s):  
Mingnian Wang ◽  
Yunpeng Hu ◽  
Cheng Jiang ◽  
Yicheng Wang ◽  
Dagang Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Relative Humidity ◽  
Mechanical Characteristics ◽  
Coupling Effect ◽  
Peak Stress ◽  
Curing Temperature ◽  
Peak Strain ◽  
Humidity Effect ◽  
Grouting Material ◽  
Study Results

The cement-based grouting materials used for practical purposes in high-geothermal tunnels are inevitably affected by humidity and high temperature, leading to the deterioration of mechanical properties. Based on the characteristics of changing high temperatures and two typical conditions of hot-humid and hot-dry environments in high-geothermal tunnels, many mechanical strength tests were carried out on the grouting material cured under different environmental conditions. The study results indicated that high temperature and low relative humidity were unfavorable to the development of mechanical characteristics of grouting material, but the coupling effect of two factors could improve the strength at early ages and reduce the degradation of long-term strength. As the curing temperature exceeded 56.3 °C, the humidity effect on strength played a more important role in recovering the strength of grouting material damaged by high temperature. Temperature had more significant impact on the relative peak stress while the relative humidity had greater influence on the relative peak strain. A calculation compressive constitutive model was prospered, which considering both temperature and relative humidity. The study results may provide much valuable experimental data and theoretical supporting for the design of compression constitutive of cement-based grouting material in high-geothermal tunnel.

scholarly journals Evaluation of Waste Cooking Oil as Sustainable Binder for Building Blocks

2018 ◽  
Vol 65 ◽  
pp. 05003
Author(s):  
Johnson Olufemi Adebayo ◽  
Madzlan Napiah ◽  
Kamaruddin Ibrahim ◽  
Mohamad Raduan Kabit
Keyword(s):  
Building Blocks ◽  
Waste Cooking Oil ◽  
Curing Temperature ◽  
Environmentally Sustainable ◽  
Material Resources ◽  
Cooking Oil ◽  
Mechanical And Physical Properties ◽  
Rate Of Absorption ◽  
Temperature Ranges ◽  
Curing Age

Increasing depletion of material resources and concern for the environment has led to the great quest for degradable and environmentally sustainable material in various industries in recent years. Application of Waste Vegetable oils as a renewable and biodegradable binder material was explored in this work. Block samples were prepared with 10% liquid binder of vegetable oil, compacted with 75 impact blows and thermally cured in a conventional oven at temperature ranges of 160-200°C. This study explores the effectiveness of waste cooking oil as a novel binder in the production of building block, called WasteVege block. Important parameters such as optimum binder content, optimum curing temperature, and optimum curing age were established. The mechanical and physical properties of the product were examined, the result shows that compressive strength in ranges of 5 - 34 MPa was achieved, initial rate of absorption (IRA), water absorption, efflorescence, and wet/dry durability of the product exhibit acceptable values within the threshold of required standards.

Statistical Damage Constitutive Model for Concrete under Biaxial Tension

2013 ◽  
Vol 438-439 ◽  
pp. 183-186
Author(s):  
Wei Feng Bai ◽  
Jun Hong Zhang ◽  
Jun Feng Guan ◽  
Ying Cui
Keyword(s):  
Constitutive Model ◽  
Biaxial Tension ◽  
Damage Model ◽  
Damage Mechanism ◽  
Deformation Properties ◽  
Damage Constitutive Model ◽  
Strength And Deformation ◽  
Statistical Damage Constitutive Model ◽  
Damage Theory ◽  
Statistical Damage

Based on the statistical damage theory and the experimental phenomena, the statistical damage constitutive model for concrete under biaxial tension is proposed. The two meso-scale damage modes, rupture and yield are considered, and the whole damage evolution process is driven by the principal tensile damage strain. The results show that the proposed statistical damage model can accurately predict the constitutive behavior in the uniform damage phase for concrete under biaxial tension. The damage mechanism is discussed in the view point of biaxial strength and deformation properties.

scholarly journals A Multiparameter Damage Constitutive Model for Rock Based on Separation of Tension and Shear

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
YanHui Yuan ◽  
Ming Xiao
Keyword(s):  
Constitutive Model ◽  
Damage Model ◽  
Damage Mechanism ◽  
Internal Variable ◽  
Damage Variable ◽  
Tensor Form ◽  
Shear Damage ◽  
Damage Constitutive Model ◽  
Microscopic Damage ◽  
Elastoplastic Damage

By analysis of the microscopic damage mechanism of rock, a multiparameter elastoplastic damage constitutive model which considers damage mechanism of tension and shear is established. A revised general form of elastoplastic damage model containing damage internal variable of tensor form is derived by considering the hypothesis that damage strain is induced by the degeneration of elastic modulus. With decomposition of plastic strain introduced, the forms of tension damage variable and shear damage variable are derived, based on which effects of tension and shear damage on material’s stiffness and strength are considered simultaneously. Through the utilizing of Zienkiewicz-Pande criterion with tension limit, the specific form of the multiparameter damage model is derived. Numerical experiments show that the established model can simulate damage behavior of rock effectively.

STOCHASTIC VISCOUS-DAMAGE CONSTITUTIVE MODEL FOR CONCRETE

2013 ◽  
Vol 07 (03) ◽  
pp. 1350027
Author(s):  
JIE LI ◽  
QIAOPING HUANG
Keyword(s):  
Damage Model ◽  
Damage Mechanism ◽  
Failure Behavior ◽  
Strain Rates ◽  
Rate Dependency ◽  
Rate Dependent ◽  
Proposed Model ◽  
Model Predictions ◽  
Damage Constitutive Model ◽  
Stochastic Damage

A new rate-dependent stochastic damage model for the dynamic modeling of concrete is presented in the paper. This model is formulated on the basis of the stochastic damage model, from which, the static stochastic evolution of damage is strictly derived. Then, rate dependency of concrete is included by means of viscous-damage mechanism. The model predictions are tested against experimental results on concrete specimens that cover different strain rates. The results demonstrate the proposed model may predict dynamic failure behavior of concrete quite well.

Sign in / Sign up

Export Citation Format

Share Document