Numerical Simulation of Rock Failure Process with a 3D Grain-Based Rock Model

A grain-based rock model was developed and applied to study mechanical characteristics and failure micromechanics in thick-walled cylinder and wellbore stability tests. The rock is represented as an assembly of tetrahedral blocks with bonded contacts. Material heterogeneity is modeled by varying the tensile strength at the block contacts. This grain-based rock model differs from previous disk/sphere particle-based rock models in its ability to represent a zero (or very low) initial porosity condition, as well as highly interlocked irregular block shapes that provide resistance to movement even after contact breakage. As a result, this model can reach higher uniaxial compressive strength to tensile strength ratios and larger friction coefficients than the disk/sphere particle-based rock model. The model captured the rock fragmentation process near the wellbore due to buckling and spalling. Thin fragments of rock similar to onion skins were produced, as observed in laboratory breakout experiments. The results suggest that this approach may be well suited to study the rock disaggregation process and other geomechanical problems in the rock excavation.

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Numerical Simulation of Compressive Experiment for Rock with a Natural Interlayer

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.217-219.1389 ◽

2012 ◽

Vol 217-219 ◽

pp. 1389-1392

Author(s):

Feng Shan Han ◽

Li Song

Keyword(s):

Numerical Simulation ◽

Compressive Strength ◽

Process Analysis ◽

Failure Process ◽

Peak Load ◽

Strain Curve ◽

Confining Pressure ◽

Physical Experiment ◽

Stress Strain Curve ◽

Rock Failure Process

It is difficulty to make physical experiment for compressive experiment of rock with a natural interlayer I Natural interlayer affect greatly on mechanical property of rock. In this paper, Rock Failure Process Analysis Code RFPA is used to simulate influence of natural interlayer to compressive strength of rock by numerical simulation under compression. Through numerical simulation complete stress strain curve and peak load can be obtained for compressive experiment of rock with a natural interlayer. RFPA can be effectively used to investigate anisotropy of compression for rock with natural interlayer under different confining pressure. Numerical simulation show that anisotropy of compressive strength of rock with a natural interlayer varies with inclination of natural interlayer, as the confining pressure increase, the compressive strength, the plasticity and ductility increase for rock with a natural interlayer. That provides new method to analyze and investigate mechanical behavior for multilayer composite material such as rock mass with a natural interlayer，finally Index of Anisotropy for rock with a natural interlayer are put forward

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Amorphous fiber based on the Fe-B-C molten system for bulk reinforcement of concrete

MATEC Web of Conferences ◽

10.1051/matecconf/201824503019 ◽

2018 ◽

Vol 245 ◽

pp. 03019 ◽

Cited By ~ 2

Author(s):

Artemiy Cherkashin ◽

Yasmin Begich ◽

Polina Sherstobitova ◽

Oleg Tolochko

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Mechanical Characteristics ◽

Test Material ◽

Comparative Tests ◽

Physical And Mechanical Characteristics

The article deals with the use of amorphous fiber of the Fe-B-C system, which was obtained by spinning the melt. Comparative tests of the samples made on the basis of the test material on the compressive strength and tensile strength of the traditional destructive method were made. The conductivity of the samples was also tested. Physical and mechanical characteristics of the material are obtained.

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Adherence between steel bars and lightweight concrete with EPS beads

Revista IBRACON de Estruturas e Materiais ◽

10.1590/s1983-41952017000100007 ◽

2017 ◽

Vol 10 (1) ◽

pp. 122-140

Author(s):

A. L. SARTORI ◽

L. M. PINHEIRO ◽

R. M. DA SILVA ◽

S. B. FREITAS ◽

T. G. CESAR

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Mechanical Characteristics ◽

Lightweight Concrete ◽

Monotonic Loading ◽

Adherence Behavior ◽

Ordinary Concrete ◽

Cylinder Test ◽

Pull Out ◽

Steel Bars

Abstract This paper describes the adherence behavior of a structural lightweight concrete with EPS beads (SLCEB) in a monotonic loading, based in a bibliographic review and in pull-out tests. The results of these SLCEB tests were compared with those of an ordinary concrete (OC) and with the values based in indications of the Brazilian code ABNT NBR 6118:2014 - Design of concrete structures. The pull-out tests of two batches of SLCEB and one of OC were analyzed, in a total of 60 tests. Mechanical characteristics were determined too, such as: compressive strength and tensile strength in split cylinder test. The calculated results according to the above mentioned standard were very different from those obtained in the tests, indicating that the theoretical values are more conservative than the experimental ones. It was also verified that it is possible to use SLCEB in structures with respect to the adequate adherence of reinforcement in the concrete.

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AN INVESTIGATION ON THE EFFECTS OF MICRO-PARAMETERS ON THE STRENGTH PROPERTIES OF ROCK

Rudarsko-geološko-naftni zbornik ◽

10.17794/rgn.2021.1.9 ◽

2021 ◽

Vol 36 (1) ◽

pp. 111-119

Author(s):

Behzad Jafari Mohammadabadi ◽

Kourosh Shahriar ◽

Hossein Jalalifar ◽

Kaveh Ahangari

Keyword(s):

Mechanical Properties ◽

Numerical Simulation ◽

Tensile Strength ◽

Compressive Strength ◽

Friction Coefficient ◽

Critical Stress ◽

Friction Angle ◽

Strength Properties ◽

Brazilian Tensile Strength ◽

The Relationship

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.

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Influence of Palm Oil Fibers Length Variation on Mechanical Properties of Reinforced Crude Bricks

10.4028/www.scientific.net/cta.1.707 ◽

2022 ◽

Author(s):

Mazhar Hussain ◽

Daniel Levacher ◽

Nathalie Leblanc ◽

Hafida Zmamou ◽

Irini Djeran Maigre ◽

...

Keyword(s):

Thermal Conductivity ◽

Tensile Strength ◽

Compressive Strength ◽

Thermal Properties ◽

Composite Materials ◽

Physical Properties ◽

Palm Oil ◽

Mechanical Characteristics ◽

Natural Fibers ◽

Indirect Tensile

Crude bricks are composite materials manufactured with sediments and natural fibers. Natural fibers are waste materials and used in construction materials for reinforcement. Their reuse in manufacturing reinforced crude bricks is eco-friendly and improves mechanical and thermal characteristics of crude bricks. Factors such as type of fibers, percentage of fibers, length of fibers and distribution of fibers inside the bricks have significant effect on mechanical, physical and thermal properties of biobased composite materials. It can be observed by tests such as indirect tensile strength, compressive strength for mechanical characteristics, density, shrinkage, color for physical properties, thermal conductivity and resistivity for thermal properties, and inundation test for durability of crude bricks. In this study, mechanical and physical characteristics of crude bricks reinforced with palm oil fibers are investigated and effect of change in percentage and length of fibers is observed. Crude bricks of size 4*4*16 cm3 are manufactured with dredged sediments from Usumacinta River, Mexico and reinforced with palm oil fibers at laboratory scale. For this purpose, sediments and palm oil fibers characteristics were studied. Length of fibers used is 2cm and 3cm. Bricks manufacturing steps such as sediments fibers mixing, moulding, compaction and drying are elaborated. Dynamic compaction is opted for compaction of crude bricks due to energy control. Indirect tensile strength and compressive strength tests are conducted to identify the mechanical characteristics of crude bricks. Physical properties of bricks are studied through density and shrinkage. Durability of crude bricks is observed with inundation test. Thermal properties are studied with thermal conductivity and resistivity test. Distribution and orientation of fibers and fibers counting are done to observe the homogeneity of fibers inside the crude bricks. Finally, comparison between the mechanical characteristics of crude bricks manufactured with 2cm and 3cm length with control specimen was made.

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Numerical Simulation on Failure Patterns of Rock Discs and Rings Subject to Diametral Line Loads

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.261-263.1517 ◽

2004 ◽

Vol 261-263 ◽

pp. 1517-1522 ◽

Cited By ~ 3

Author(s):

Wan Cheng Zhu ◽

K.T. Chau ◽

Chun An Tang

Keyword(s):

Tensile Strength ◽

Standardized Test ◽

Process Analysis ◽

Failure Process ◽

Brazilian Test ◽

Rock Failure ◽

Numerical Code ◽

Failure Patterns ◽

Rock Failure Process ◽

Indirect Tensile

Brazilian test is a standardized test for measuring indirect tensile strength of rock and concrete disc (or cylinder). Similar test called indirect tensile test has also been used for other geomaterials. Although splitting of the disc into two halves is the expected failure mode, other rupture modes had also been observed. More importantly, the splitting tensile strength of rock can vary significantly with the specimen geometry and loading condition. In this study, a numerical code called RFPA2D (abbreviated from Rock Failure Process Analysis) is used to simulate the failure process of disc and ring specimens subject to Brazilian test. The failure patterns and splitting tensile strengths of specimens with different size and loading-strip-width are simulated and compared with existing experimental results. In addition, two distinct failure patterns observed in ring tests have been simulated using RFPA2D and thus this verifies the applicability of RFPA2D in simulating rock failure process under static loads.

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Numerical Simulation of Influence of Mudstone Interlayer on Compressive Strength of Salt Rock

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.512-515.1953 ◽

2012 ◽

Vol 512-515 ◽

pp. 1953-1956

Author(s):

Feng Shan Han ◽

Song Li

Keyword(s):

Numerical Simulation ◽

Compressive Strength ◽

Natural Gas ◽

Radioactive Waste ◽

Mechanical Behavior ◽

Uniaxial Compressive Strength ◽

Failure Process ◽

Physical Experiment ◽

Salt Rock ◽

Oil And Natural Gas

Salt rock is think of ideal storage location for oil and natural gas and radioactive waste deposited, interlayer has negative effect on stability of cavern of storage for oil and natural gas and radioactive waste deposited in salt rock, It is difficult to make complete specimen layered salt rock with interlayer. In this paper Based on Rock Failure Process Analysis Code RAFP2D, influence of mudstone interlayer on uniaxial compressive strength of salt rock is investigated by numerical simulation. Numerical simulation shown that when mechanical parameters such as elastic modulus poison’s ratio and uniaxial compressive strength for salt rock and pure mudstone interlayer and content of mudstone interlayer in salt rock are known, compressive strength and mechanical behavior for salt rock with mudstone interlayer can be effectively and accurately analyzed using RFAP2D. The results for numerical simulation are agreement with true physical experiment of salt rock with mudstone interlayer. It should be noticed that the true physical experimental uniaxial compressive strength of rock is in range of 30% mean uniaxial compressive strength of rock element in RFPA2D，in this case the results for numerical simulation can reflect phenomenon and behavior for true physical experiment of salt rock with mudstone interlayer. That provides new method and avenue to analyze and investigate mechanical behavior for multilayer rock mass based on RAFP2D

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Numerical Investigation for Fracture Saturation in Multilayer Sedimentary Rock in Unsymmetrical Case

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.690-693.3050 ◽

2013 ◽

Vol 690-693 ◽

pp. 3050-3053

Author(s):

Feng Shan Han ◽

Li Song

Keyword(s):

Numerical Simulation ◽

Layer Thickness ◽

Sedimentary Rock ◽

Process Analysis ◽

Failure Process ◽

Bottom Layer ◽

Thickness Ratio ◽

Fracture Spacing ◽

Layer Thickness Ratio ◽

Rock Failure Process

Opening mode fractures in multilayer sedimentary rock often are periodically distributed with fracture spacing scaled to the thickness of the fractured layer. In this paper, based on Rock Failure Process Analysis Code RFPA2D, a three layer model with a central layer and with the different thickness top and bottom layer, progressive formation in multilayer sedimentary rock at fracture saturation in unsymmetrical case is simulated. We investigate the change of the critical fracture spacing to layer thickness ratio as a function of the thickness of the top layer where the bottom layers is much thicker (5 times) than the fractured layer called the unsymmetrical case, in this unsymmetrical case, fracture saturation is simulated. By numerical simulation of RFPA2D, the critical spacing to layer thickness ratio decreases and tend to the same constant value as the thickness of the top layer increases. Numerical simulation shown that for the unsymmetrical case, if the adjacent layers are thicker than 1.5 times the thickness of the fractured layer, the multilayer sedimentary rock can be treated approximately as a system with infinitely thick top and bottom layers at fracture saturation.That should be useful in the design of engineering systems and in the prediction of fracture spacing in hydrocarbon reservoirs and groundwater aquifers.

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Experimental Study of the Mechanical Behaviour of Brick Waste Concrete and Analytical Prediction of its Elastic Modulus as a Three-Phase Composite Material

International Journal of Engineering Research in Africa ◽

10.4028/www.scientific.net/jera.57.125 ◽

2021 ◽

Vol 57 ◽

pp. 125-138

Author(s):

Wafa Ben Achour ◽

Saloua El Euch Khay ◽

Karim Miled ◽

Jamel Neji

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Elastic Modulus ◽

Mechanical Behaviour ◽

Mechanical Characteristics ◽

Splitting Tensile Strength ◽

Analytical Prediction ◽

Waste Concrete ◽

Three Phase ◽

Substitution Ratio

This paper focuses on the characterization of the mechanical behaviour of concrete incorporating different percentages of brick waste aggregates (BWA). Compressive strength, splitting tensile strength and elastic modulus of this material were measured based on standard laboratory tests and its microstructure was characterized based on scanning electron microscope (SEM) observations. A decrease in these properties was observed with the increase of BWA substitution ratio. However, this decrease remains moderate up to a substitution percentage of 30% (about 12% for compressive strength and elastic modulus and 8% for splitting-tensile strength). In addition, an increase in the concrete porosity was observed with the increase of BWA substitution ratio, which can explain the decrease observed in the measured mechanical characteristics. SEM views on concrete incorporating 100% of BWA showed that the interfacial transition zone (ITZ) and the cement paste present a higher porosity when compared to those of the reference concrete made with natural aggregates.Finally, a micromechanical analytical homogenization model predicting the elastic modulus of brick waste concrete (BWC) according to its composition is proposed where BWC is modelled as a three-phase composite. A good agreement was found between analytical predictions and experimental results proving that BWC mechanical characteristics are mainly governed by BWA mechanical properties and their volume fraction within concrete.

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