scholarly journals Experimental Study on the Calibration of Microparameters of Dolomite in the Barun Open-Pit Mine on the Basis of the Parallel Bond Model

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhiheng Dang ◽  
Zuoming Yin ◽  
Desheng Wang ◽  
Mingyu Fu ◽  
Qi Yin
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Uniaxial Compression ◽  
Open Pit Mine ◽  
Particle Flow ◽  
Open Pit ◽  
Test Results ◽  
Compression Tests ◽  
Simulation Test ◽  
Bond Model

The microparameter calibration of the particle flow parallel bond model (PBM) is mostly based on a uniaxial compression test. The microparameters calibrated only by uniaxial compression tests cannot be directly used to study the mechanical properties of rocks with surrounding pressure conditions. To analyze the relationship between the macroparameters and microparameters in the model and select appropriate particle flow model parameters, this study conducted a particle flow numerical simulation experiment based on the basic test principles of the uniaxial compression, Brazilian splitting, and triaxial compression tests. An orthogonal experimental design was performed for the calibration of the microparameters of the particle flow PBM, and multifactor analysis of variance was used to screen out the factors that have a considerable influence on the experimental indicators. Regression analysis was performed on the significant influencing factors and test indicators, and the corresponding linear and nonlinear relationships between the macroparameters and microparameters were obtained. Lastly, the microparameters of the model were determined in accordance with the macroparameters of the mechanical test of the Barun open-pit mine dolomite, and a numerical simulation test was conducted. Simulation test results were consistent with the actual test results, thus providing a basis for a subsequent numerical simulation study on the mechanical properties of dolomite.

Mechanical Properties of Hypereutectoid Steel with Microduplex (α+θ) Structure Formed by Hot Deformation of Undercooled Austenite

2010 ◽  
Vol 654-656 ◽  
pp. 246-249
Author(s):  
Long Fei Li ◽  
Wei Chen ◽  
Wang Yue Yang ◽  
Zu Qing Sun
Keyword(s):  
Mechanical Properties ◽  
Hot Deformation ◽  
Ferrite Matrix ◽  
Subsequent Annealing ◽  
Test Machine ◽  
Compression Tests ◽  
Simulation Test ◽  
Hypereutectoid Steel ◽  
Lamellar Pearlite ◽  
Undercooled Austenite

Microstructure evolution and mechanical properties of hypereutectoid steel with the microduplex (α+θ) structures formed by hot deformation of undercooled austenite were investigated by hot uniaxial compression tests in a Gleeble-1500 simulation test machine, and the effects of subsequent annealing and the addition of Al were analyzed. The results indicated that at the beginning of hot deformation of undercooled austenite the formation of proeutectoid cementite was retrained and only lamellar pearlite was produced. With further strain, dynamic spheroidization of pearlite took place, leading to the formation of microduplex (α+θ) structure consisting of ultrafine ferrite matrix and dispersed cementite particles. In comparison with the normal microstructure consisting of lamellar pearlite and proeutectoid cementite, the microduplex (α+θ) structure presented higher strengths with similar ductility. Subsequent annealing could make the microduplex (α+θ) structure more uniform, which demonstrated better balance between strength and ductility. The addition of Al is disadvantageous to the formation of microduplex (α+θ) structure, but can result in the further refinement. With the addition of Al, the strength of microduplex (α+θ) structure was improved and the ductility was not deteriorated markedly.

Stabilization of clayey subgrade with waste pumice for road infrastructure

2015 ◽  
Vol 22 (5) ◽  
Author(s):  
Ömür Çimen ◽  
Mehmet Saltan ◽  
S. Nilay Keskin
Keyword(s):  
Mechanical Properties ◽  
Road Construction ◽  
High Plasticity ◽  
Test Results ◽  
Index Properties ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Swelling Potential ◽  
Project Costs ◽  
High Plasticity Clay

AbstractHigh-plasticity clayey subgrade, which is unsuitable for road construction, may sometimes occur along highway routes. In such cases, engineers need to change the route of a highway project, resulting in an increase in road length and project costs. In this study, waste pumice was examined for stabilization of high-plasticity clayey subgrade, which is inappropriate for road construction. For this purpose, the physical and index properties of clay and pumice were determined. Then, the pumice was mixed with high plasticity clay at different ratios by weight. By performing standard Proctor compaction tests on the mixtures, the effects of adding pumice on compaction were also studied. Unconfined compression tests and California bearing ratio (CBR) tests were performed on all pumice-clay mixtures, and the test results and the CBR ratios were compared for each sample, respectively. The results showed that pumice stabilization improved the mechanical properties and reduced the swelling potential of high plasticity clayey subgrade.

Behaviors of Xiashu Loess in the Lower Reaches of China’s Yangtze River under Triaxial Compression and the Microscopic Explanations

2016 ◽  
Vol 858 ◽  
pp. 91-97
Author(s):  
Jun Hua Xiao ◽  
Wen Qi Zheng
Keyword(s):  
Mechanical Properties ◽  
Yangtze River ◽  
Shear Failure ◽  
Triaxial Compression ◽  
Processing Technique ◽  
Point Of View ◽  
Image Processing Technique ◽  
Test Results ◽  
Compression Tests ◽  
Triaxial Compression Tests

To investigate the macroscopic mechanical properties of undisturbed structural Xiashu loess in the lower reaches of China’s Yangtze River under triaxial compression, and obtain the intrinsic explanations for the macroscopic mechanical properties from the microscopic point of view, in laboratory, triaxial compression tests were carried out, microstructure images of sheared samples were collected by scanning electron microscope (SEM), and quantitative parameters of microstructure (mainly about particle or pore size, distribution, and alignment) were extracted by digital image processing technique. Based on the test results, the deviator stress-strain relationships of both undisturbed and remoulded Xiashu loess, the structural strength, and the microstructural evolution mechanism about the formation of shear failure zone of Xiashu loess under triaxial compression were analyzed.

scholarly journals Numerical Simulation Analysis of NPR Anchorage Monitoring of Bedding Rock Landslide in Open-Pit Mine

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Kai Zhang ◽  
Xiaojie Yang ◽  
Xuebin Cui ◽  
Yong Wang ◽  
Zhigang Tao
Keyword(s):  
Numerical Simulation ◽  
Early Warning ◽  
Simulation Analysis ◽  
Failure Process ◽  
Open Pit Mine ◽  
Open Pit ◽  
Stress Monitoring ◽  
Anchor Cable ◽  
Whole Process ◽  
Rock Landslide

Nanfen open-pit iron mine is the largest single open-pit mine in Asia. Because of the lag of the extension project, the section has slowly spread in the shape of “V,” and disasters such as landslides occur frequently. In this study, first, the NPR anchor cable monitoring, which shows supernormal mechanical characteristics and can realize the monitoring and early warning target for the whole landslide process and early warning curve of bedding rock “2016-1101 landslide” in the lower wall of Nanfen open-pit mine, was analyzed, revealing the failure process of the bedding rock landslide and the force evolution characteristics of the NPR anchor cable. Then, based on the Fish language in FLAC3D and 3DEC software, the mechanical model of the NPR anchor cable was constructed, and numerical simulation was performed on the whole process of “16-1101 landslide” induced by accumulation of old landslide body. The results of this study indicate that the stress monitoring curves and failure characteristics of the NPR anchor cables in the whole process of landslide by the two numerical simulation methods are basically consistent with the field measurement results, providing a theoretical and practical basis for the mechanistic analysis and numerical simulation of other similar slopes.

scholarly journals Mechanical Characterizations of Oxidizing Steel Slag Soil and Application

2017 ◽  
Author(s):  
Tao Cheng ◽  
Renjie Hu ◽  
Wanhui Xu ◽  
Yi Zhang
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Electric Furnace ◽  
Practical Problem ◽  
Steel Slag ◽  
Problem Analysis ◽  
Compression Tests ◽  
Optimal Moisture Content ◽  
Eaf Slag ◽  
Furnace Slag

In this paper, the mechanical properties and engineering applicationof electric furnace (EAF) slag mixed soil are investigated.The samples of steel slag are taken from a steel manufacturingcompany in Huangshi, a city of China. The mixed soilwas firstly prepared by mixing the steel slag and clay mixturein different proportions. The optimal moisture content for mixingthe soil is investigated from the experiment through directshear test. Based on three axial compression tests, the optimumsteel slag ratio is determined. Finally, the mechanical propertiesof steel slag mixed soil are tested in a practical engineeringproblem through a numerical simulation. The steel slag mixedsoil is used to replace the original soil of the embankment andcompared with that of the original one. The comparison studyshows that the method proposed in this paper is simple andeffective. Moreover, from the practical problem analysis, theoptimal utilization of electric furnace slag can be achieved.

scholarly journals The numerical simulation of Influence of Drying-wetting Cycles on the Deterioration Characteristics of Gypsum Rocks under Particle Flow Code

2020 ◽  
Vol 24 (1) ◽  
pp. 55-59
Author(s):  
Guopeng Wu ◽  
Wenwu Chen ◽  
Kai Cui
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Water Absorption ◽  
Absorption Rate ◽  
Early Stage ◽  
Particle Flow ◽  
Wetting And Drying ◽  
Water Absorption Rate ◽  
Gypsum Rock ◽  
Deterioration Characteristics

In order to study the influence of dry-wet cycling on the deterioration characteristics of gypsum rocks and solve the problems encountered in engineering construction, in this study, gypsum rocks are taken as the research object. With the combination of laboratory test and theoretical analysis, the numerical simulation of particle flow is carried out, and the deterioration characteristics of physical and mechanical properties of gypsum rock under dry-wet cycling are studied. The results show that gypsum, quartz, zeolite and dolomite are the main components of gypsum rocks. Gypsum occupies the most components in gypsum rocks, so the various characteristics of gypsum greatly affect the characteristics of gypsum rocks. The process of water absorption and loss of gypsum is similar, which shows that the rate of water absorption or loss of gypsum is faster in the early stage, and tends to be stable in the later stage. The curve of the whole process of water absorption and loss is fitted by negative exponential function, and the effect is better. The larger the porosity of gypsum rock is, the better its water absorption performance is. Intergranular pore, dissolution pore and dissolution pore are the main pore types of gypsum rock. Intergranular pore is the main water absorption channel of gypsum rock. The cumulative water absorption increases with the increase of wetting and drying cycles. The change of water absorption curve is mainly manifested in water absorption rate and time. The more the number of wet-dry cycles is, the higher the water absorption rate in the early stage of water absorption is, the closer the characteristic curve to the coordinate axis of water absorption is, and the shorter the water absorption time is. In contrast, the shape difference of water loss curve is very small. It can be seen from this that in the process of wetting and drying cycle, the hydrophysical and hydrochemical processes promote each other, which changes the crystal structure and pore structure of gypsum rocks, reduces the crystal strength and increases the porosity, thus leading to the deterioration of the mechanical properties of gypsum rocks.

scholarly journals GEOMETRY AND MECHANICAL PROPERTIES OF A 3D-PRINTED TITANIUM MICROSTRUCTURE

2018 ◽  
Vol 15 ◽  
pp. 104-108
Author(s):  
Luboš Řehounek ◽  
Petra Hájková ◽  
Petr Vakrčka ◽  
Aleš Jíra
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Uniaxial Compression ◽  
Elastic Moduli ◽  
Weight Ratio ◽  
Porous Structures ◽  
Compression Tests ◽  
Local Material ◽  
3D Printed ◽  
Titanium Microstructure

Construction applications sometimes require use of a material other than construction steel or concrete – mainly in cases, where strength to weight ratio needs to be considered. A suitable solution to this problem are structures manufactured using the 3D printing process, as they have a very good strength to weight ratio (i.e.: Ti-6Al-4V – σ<sub>ult</sub> = 900 MPa and ρ = 4500 kg/m<sup>3</sup>). Trabecular structures are porous structures with local material characteristics identical to their commonly manufactured counterparts, but due to their geometry, they have different global mechanical properties and are suited for special applications. We designed and manufactured six variants of these structures and subjected them to uniaxial compression tests, nanoindentation tests and subsequently evaluated their differences and elastic moduli. The values of global moduli E are in the range of 2.55 GPa – 3.55 GPa for all specimens.

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