Experimental Study on Strength and Deformation of Brittle Rock under Different Compression Condition

2011 ◽  
Vol 675-677 ◽  
pp. 511-514
Author(s):  
Jia Wen Zhou ◽  
Xing Guo Yang ◽  
Hong Tao Li
Keyword(s):  
Triaxial Compression ◽  
Experimental Tests ◽  
Peak Strength ◽  
Brittle Rock ◽  
Test Results ◽  
Confining Stress ◽  
Strength And Deformation ◽  
Loading And Unloading ◽  
Mechanics Characteristics ◽  
Compression Condition

This paper studies on the characteristics of strength and deformation of brittle rock under different compression condition by experimental tests. A lot of experimental tests for the Xiangjiaba sandstone are carried out under different compression condition, including uniaxial compression, triaxial compression, uniaxial monocyclic compression and uniaxial loading and unloading. Base on the experimental test results of the Xiangjiaba sandstone, the strength and deformation of brittle rock are analyzed, and some comparative analysis for the mechanics characteristics of brittle rock are carried out. The compute results show that, the peak strength of brittle rock is increased with the confining stress, and close to a linear relationship. Its also show that, the peak strength is not increased under the monocyclic compression, neither for the loading and unloading condition.

Mechanical and Dynamic Characteristics of Laminated Glass Sheets Used for Staircases

2014 ◽  
Vol 601 ◽  
pp. 227-230
Author(s):  
Cristian Lucian Ghindea ◽  
Dan Cretu ◽  
Radu Cruciat ◽  
Ovidiu Bogdan
Keyword(s):  
Mechanical Characteristics ◽  
Experimental Tests ◽  
Laminated Glass ◽  
Deformation Capacity ◽  
Test Results ◽  
Dynamic Tests ◽  
Tempered Glass ◽  
Successful Design ◽  
Strength And Deformation ◽  
Static And Dynamic Tests

In case of laminated glass strips, the mechanical characteristics of the composite element are different from the values that are obtained for the same element from a homogeneous and isotropic material. The experimental tests presented in the paper aims to determine the mechanical characteristics of laminated glass strips used to make a staircase. For the experiment, quasi-static and dynamic tests were conducted on different glass stair steps, made from normal and tempered glass, with different number and thicknesses glass sheets. The paper presents the carrying out conditions for the experiments, the synthesis of data processing and comments on the experimental results. Experimental test results led to the constructive solution of the glass staircase steps. For staircase building up, tempered glass was chosen and the values obtained for the mechanical properties, strength and deformation capacity of the system were used in its design. Whole set of experimental tests led to a successful design and build-up of the glass staircase.

Strength and deformation behavior of red sandstone under multi-stage triaxial compression

2012 ◽  
Vol 49 (6) ◽  
pp. 694-709 ◽  
Author(s):  
Sheng-Qi Yang
Keyword(s):  
Deformation Behavior ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Single Stage ◽  
Peak Strength ◽  
Red Sandstone ◽  
Triaxial Strength ◽  
Multi Stage ◽  
Strength And Deformation ◽  
The Difference

Based on multi-stage triaxial experimental results of red sandstone with circumferential deformation control, the influence of confining pressure on strength and deformation behavior of red sandstone under multi-stage triaxial compression is investigated. The results show that the confining pressure has an obvious effect on the deformation parameters of red sandstone under multi-stage triaxial compression. A multi-stage triaxial compression experiment with only one specimen can be used to confirm the peak strength of rock under different confining pressures. Under single-stage and multi-stage triaxial compression, the peak strength behavior of red sandstone agrees better with the nonlinear Hoek–Brown criterion than the linear Mohr–Coulomb criterion. However, the difference between single-stage and multi-stage triaxial strength changes with different post-peak deformation values, and the reason for the difference, is discussed. To predict single-stage triaxial strength using the obtained multi-stage triaxial strength with only one specimen, a new method is put forward to revise multi-stage triaxial strength of red sandstone, which testifies to being reasonable. The concluding remarks are very useful and significant for deep geotechnical and underground structural engineering.

scholarly journals Elastic-Plastic Threshold and Rational Unloading Level of Rocks

2019 ◽  
Vol 9 (15) ◽  
pp. 3164 ◽  
Author(s):  
Ming Ji ◽  
Hongjun Guo
Keyword(s):  
Stress Level ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Confining Stress ◽  
Elastic Plastic ◽  
Conventional Triaxial Compression ◽  
Confining Pressures ◽  
Pressure Increment ◽  
Loading And Unloading ◽  
Plastic Transformation

During loading and unloading test, various rocks manifest different stress values of elastic-plastic transformation. This study proposes to include axial pressure increment ratio in the conventional triaxial compression test to evaluate different variables (nominal elastic modulus, nominal Poisson’s ratio, strain, and energy). The relationships among various factors including variables, the stress level of initial confining stress and axial pressures, were analyzed by analyzing the stress–strain plot record obtained from testing various rocks. The extreme value point of the deformation parameter, also known as the elastic-plastic threshold, was analyzed. In addition, the elastic-plastic thresholds were later used as unloading points during the unloading tests. Under the same confining condition, different rocks demonstrated different unloading levels. Furthermore, a linear correlation was observed between unloading levels and changing confining pressures, and the gradient is mainly related to the types of rocks. During the unloading tests of rocks, the rational unloading level is recommended to be no higher than the stress level at the elastic-plastic threshold under the corresponding confining pressure.

On axial compressive behavior of steel fiber reinforced concrete confined by FRP

2021 ◽  
pp. 136943322098165
Author(s):  
Hossein Saberi ◽  
Farzad Hatami ◽  
Alireza Rahai
Keyword(s):  
Reinforced Concrete ◽  
Experimental Test ◽  
Steel Fiber ◽  
Experimental Tests ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Test Results ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Frp Confinement

In this study, the co-effects of steel fibers and FRP confinement on the concrete behavior under the axial compression load are investigated. Thus, the experimental tests were conducted on 18 steel fiber-reinforced concrete (SFRC) specimens confined by FRP. Moreover, 24 existing experimental test results of FRP-confined specimens tested under axial compression are gathered to compile a reliable database for developing a mathematical model. In the conducted experimental tests, the concrete strength was varied as 26 MPa and 32.5 MPa and the steel fiber content was varied as 0.0%, 1.5%, and 3%. The specimens were confined with one and two layers of glass fiber reinforced polymer (GFRP) sheet. The experimental test results show that simultaneously using the steel fibers and FRP confinement in concrete not only significantly increases the peak strength and ultimate strain of concrete but also solves the issue of sudden failure in the FRP-confined concrete. The simulations confirm that the results of the proposed model are in good agreement with those of experimental tests.

scholarly journals Methodology for Selecting the Operating Conditions of a Vibration Generator Used in the Hot-Dip Galvanizing Process

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2042
Author(s):  
Wojciech Kacalak ◽  
Igor Maciejewski ◽  
Dariusz Lipiński ◽  
Błażej Bałasz
Keyword(s):  
Simulation Model ◽  
Asynchronous Motor ◽  
Experimental Tests ◽  
Suspension System ◽  
Operating Conditions ◽  
Test Results ◽  
Forced Simulation

A simulation model and the results of experimental tests of a vibration generator in applications for the hot-dip galvanizing process are presented. The parameters of the work of the asynchronous motor forcing the system vibrations were determined, as well as the degree of unbalance enabling the vibrations of galvanized elements weighing up to 500 kg to be forced. Simulation and experimental tests of the designed and then constructed vibration generator were carried out at different intensities of the unbalanced rotating mass of the motor. Based on the obtained test results, the generator operating conditions were determined at which the highest values of the amplitude of vibrations transmitted through the suspension system to the galvanized elements were obtained.

Study on Constitutive Mode of Three Typical Rocks Based on Triaxial Compression Test

2012 ◽  
Vol 170-173 ◽  
pp. 322-326
Author(s):  
Kui Chen ◽  
Ren Hua Yang ◽  
Tao Xu ◽  
Ya Jing Qi
Keyword(s):  
Residual Strength ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Digital Design ◽  
Peak Strength ◽  
Design Parameters ◽  
Stress Strain ◽  
Red Sandstone ◽  
Constitutive Mode ◽  
Shield Machine

In order to study the relationship between the design parameters of the shield machine and the strength of rock, the behaviours of rocks under the conventional triaxial compression, the complete stress-strain curves under different confining pressures of three typical rocks, i.e. granite, limestone and red sandstone, were taken out for analysis. From the curves, the values of elastic modulus E and Poisson's ratio μ were gained and the relationships between the following parameters were figured out, which are peak strength versus confining pressure, residual strength versus confining pressure, strain at peak strength versus confining pressure, and strain at residual strength versus confining pressure. According to the values and relationships, the complete stress-strain curves were divided into three parts. For each part, a constitutive equation was established by using the strain softening trilinear elastic-brittle-plastic constitutive model, and all the related parameters in the constitutive equations were also presented, which provide a theoretical foundation for the digital design of the cutter head and cutters of Shield machine.

Shear connection between precast concrete bridge segments built with thin-walled elements

2021 ◽  
Author(s):  
Tobias Huber ◽  
Stephan Fasching ◽  
Johann Kollegger
Keyword(s):  
Precast Concrete ◽  
Deformation Behaviour ◽  
Lateral Force ◽  
Test Results ◽  
Construction Time ◽  
Shear Connection ◽  
Force Transfer ◽  
Strength And Deformation ◽  
Thin Walled ◽  
Segmental Bridge

<p>Segmental bridge construction combines the advantages of prefabrication, for example the reduction of construction time and very high product quality, with those of common bridge erecting methods. Short precast segments are assembled and prestressed to form the complete superstructure. New methods divide these segments into prefabricated elements to create new lighter versions of the segments. For this to work, new joint types must be developed which can ensure the force transfer between the segments. In this paper, several methods, including a new concept for joining thin-walled pre-fabricated elements, are described. Push-off tests with a constant lateral force were carried out to assess the shear strength and deformation behaviour. The main parameters were the joint type (wet joints: plain, grooved, keyed; dry joints), the mortar type, and the level of lateral force. In this paper, the test results are presented and recalculations with a design code are shown.</p>

Strength and deformation of frozen saturated sand at −30 °C

1982 ◽  
Vol 19 (1) ◽  
pp. 104-107 ◽  
Author(s):  
V. R. Parameswaran ◽  
M. Roy
Keyword(s):  
Strain Rate ◽  
Power Law ◽  
Quartz Sand ◽  
Peak Strength ◽  
Strain Rates ◽  
Saturated Sand ◽  
Ideal Plastic ◽  
Strength And Deformation ◽  
Power Law Equation

Frozen saturated quartz sand containing 20% moisture by weight, when deformed at −30 °C at various strain rates, showed various modes of behaviour such as visco-plastic, almost ideal plastic, and brittle with little plasticity with increasing order of strain rate. The values of peak strength observed for strain rates between 5 × 10−7 and 6 × 10−3 s−1 were in the range 15–42 MPa, stress being related to strain rate by a power-law equation.

Research on Hydraulic Conductivity of Coarse Sandstone under Triaxial Compression

2011 ◽  
Vol 94-96 ◽  
pp. 1146-1151 ◽  
Author(s):  
Guan Rong ◽  
Xiao Jiang Wang
Keyword(s):  
Hydraulic Conductivity ◽  
Circumferential Strain ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Test Results ◽  
Stress Strain ◽  
Deformation And Failure ◽  
Maximum Value ◽  
Strain Process ◽  
Peak Value

Permeability test for complete stress-strain process of coarse sandstone were carried out in triaxial test instrument. On the basis of test results, the influence of confining pressure and strain on the hydraulic conductivity was discussed. It is shown that in the complete stress-strain process, hydraulic conductivity changes in the law that presents the same character with the curve of stress-strain. The hydraulic conductivity reduces slightly with the increase of deviatoric stress in the stage of micro fracture compressing and elastic; In the elastoplastic stage, along with the expansion of new fractures, the hydraulic conductivity increases slowly at first and then reaches sharply to the maximum value after peak point; In the post-peak stage, the fracture which controls the hydraulic conductivity of coarse sandstone is compressed because of the confining pressure and the hydraulic conductivity decreases. During the process of deformation and failure, the hydraulic conductivity is more sensitive to the change of circumferential strain. With the increase of confining pressure, the increased value from initial to peak value and the decreased value from peak to residual value decreases.

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