scholarly journals Unconfined and Triaxial Compression Tests on Hollowed Cylindrical Sandstones to Explore the Infilling Effects on the Deformation and Mechanical Behaviors

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yong Liu ◽  
Xiao Li ◽  
Lei Weng ◽  
Qiuhong Wu ◽  
Haifan Wang
Keyword(s):  
Mechanical Properties ◽  
Carrying Capacity ◽  
Cement Mortar ◽  
Shear Fracture ◽  
Triaxial Compression ◽  
Peak Stress ◽  
Surrounding Rock ◽  
Compression Tests ◽  
Failure Patterns ◽  
Compression Condition

In practical engineering, the mechanical properties of the surrounding rock often reflect the bearing capacity of the support. To investigate the relations between the surrounding rock and the support, solid specimens, hollowed cylinders, and hollowed cylinders filled with two kinds of cement mortars are tested under unconfined and conventional triaxial compressions. The effects of the infilling on the stress-strain curves, deformation features, mechanical properties, and failure patterns are schematically investigated. The results show that under the triaxial compression condition, each infilled specimen exhibits obvious residual carrying capacity though a slight stress drop occurs after the peak stress. The cement mortar exerts a positive effect on the carrying capacity of the rock, and the infilling having a higher strength and stiffness contributes to a more pronounced enhancement of the overall strength of the specimens. Under the triaxial compression condition, merely a dominated shear fracture can be seen on the surfaces, and with relatively high confining pressure (σ3 = 20 and 30 MPa), both the rock and cement mortar were cut into two parts by the dominated shear fracture. The laboratory tests in this study provide a simple and feasible way of investigating the interaction of the support system with the surrounding rock.

scholarly journals Tests on the Mechanical Properties of Corroded Cement Mortar after High Temperature

2020 ◽  
Vol 6 (3) ◽  
pp. 459-469 ◽  
Author(s):  
Xiong Liang-Xiao ◽  
Chen Cong
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Sodium Sulfate ◽  
Sea Water ◽  
Cement Mortar ◽  
Peak Stress ◽  
Sulfate Solution ◽  
Sodium Sulfate Solution ◽  
Compression Tests

Durability of cement mortar and concrete materials under sea water condition is always an important research topic. The objective of this work is to understand the mechanical properties of corroded cement mortar after high temperature, the cement mortar specimens after high temperature were placed in water and sodium sulfate solution, and then the uniaxial compression tests were carried out on the cement mortar specimens after corroded. Test results show that both the differences of compressive strength and strain at the peak stress after high temperature caused by high temperature, are relatively small when the specimens are eroded in water, and the differences are relatively high when the specimens are eroded in sodium sulfate solution. The compressive strength of the cement mortar specimens under normal temperature eroded in sodium sulfate solution is highest, and that eroded in water is lowest. The compressive strength of specimen after high temperature eroded in water is highest and that eroded in sodium sulfate solution is lowest. The strain at the peak stress of specimen, whether after high temperature or not, is highest when eroded in sodium sulfate solution, and that eroded in water is lowest. At present, there are few research results about the mechanical properties of concrete first after high temperature and then after sea water corrosion. The work in this paper can enrich the results in this area.

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 Sensitivity Analysis in the Estimation of Mechanical Parameters of Engineering Rock Mass Based on the Hoek–Brown Criterion

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhiqiang Li ◽  
Guofeng Liu ◽  
Shuqian Duan ◽  
Shufeng Pei ◽  
Changgen Yan
Keyword(s):  
Rock Mass ◽  
Triaxial Compression ◽  
Damage Zone ◽  
Surrounding Rock ◽  
Geological Strength Index ◽  
Sensitivity Factor ◽  
Mechanical Parameters ◽  
Compression Tests ◽  
Disturbance Factor

Geological strength index GSI, disturbance factor (D), material constant mi, and uniaxial compressive strength σci of the intact rock are essential input parameters IPs of the Hoek–Brown H−B criterion. Mechanical parameters MPs of the engineering rock mass, including elastic modulus E, cohesion c, and internal friction angle φ estimated by the H–B criterion, and the predicted excavation response of surrounding rock, including the displacement and excavation damage zone EDZ based on the MPs, are of high relevance with the four IPs of the H–B criterion. In this paper, the deep and huge underground cavern excavated in basalt from a hydropower station under construction in the southwest of China is used to analyse the sensitivity of the IPs on the MPs, the displacement, and EDZ of the surrounding rock mass. Firstly, the H–B criterion is applied to estimate the MPs, among which the IPs are obtained from a series of in situ and laboratory tests, including borehole camera observation, wave velocity test, uniaxial and triaxial compression tests, and so on. Secondly, the sensitivity relationships between IPs, MPs, and prediction results of displacement and EDZ are established and described quantitatively by the sensitivity factor (si). Results show that the MPs of the rock mass are more sensitive to GSI and D⋅GSI and σci are high-sensitivity parameters affecting the displacement and EDZ. Finally, the variations in the estimated MPs and associated prediction results concerning excavation response, which are caused by the uncertainties in the determination of the IPs, are further quantified. This study provides a straightforward assessment for the variability of the rock mass parameters estimated by the H–B criterion. It also gives a valuable reference to similar geotechnical engineering for the determination of rock mass parameters in the preliminary design.

Numerical Simulation of Mechanical Properties of Reinforced Red-Sandstone Granular Soil Based on 3D Discrete Element Method

2013 ◽  
Vol 353-356 ◽  
pp. 802-805
Author(s):  
Jian Qing Jiang
Keyword(s):  
Mechanical Properties ◽  
Discrete Element Method ◽  
Triaxial Compression ◽  
Discrete Element ◽  
Reinforced Soil ◽  
Triaxial Tests ◽  
Granular Soil ◽  
Compression Tests ◽  
Red Sandstone ◽  
Element Method

Red-sandstone granular soil reinforced with gabion-mesh is a new concept of composite reinforced soil. In order to reveal the mechanical properties of this composite reinforced soil, a series of laboratory triaxial compression tests on specimens reinforced with gabion-mesh were carried out, and 3D discrete element method was introduced to simulate the triaxial tests. The macro stress-strain relation of red-sandstone specimens reinforced with gabion-mesh was reproduced by the 3D discrete element model. The results show that 3D discrete element method is an ideal technique to study the meso-mechanical nature characteristics of gabion-mesh reinforced red-sandstone granular soil.

scholarly journals Microcracking and the failure of polycrystalline ice under triaxial compression

1992 ◽  
Vol 38 (128) ◽  
pp. 65-76 ◽  
Author(s):  
P. Kalifa ◽  
G. Ouillon ◽  
P. Duval
Keyword(s):  
Triaxial Compression ◽  
Peak Stress ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Strain History ◽  
Compression Tests ◽  
Brittle Transition ◽  
Polycrystalline Ice ◽  
Strain Components

AbstractTriaxial and uniaxial compression tests have been carried out at –10°C on granular ice in order to study the role of microcracking on failure in the ductile-brittle transition zone. In the triaxial tests, the effect of confining pressure and strain rate on the crack population, as well as on strength and strain at the peak stress, was investigated. In the uniaxial tests, we measured the evolution of elastic and non-elastic components of deformation with the stress-strain history. The concept of effective stress, with a single scalar damage variable, was used to calculate the effect of microcracking on the strain components.

Numerical Simulation of the Effect of Temperature on the Failure Strength of Rock

2013 ◽  
Vol 690-693 ◽  
pp. 1737-1740
Author(s):  
Lin Bu ◽  
Tao Xu ◽  
Yun Jie Zhang
Keyword(s):  
Mechanical Properties ◽  
Rock Fracture ◽  
Strain Curve ◽  
Peak Stress ◽  
Effect Of Temperature ◽  
Peak Strain ◽  
Failure Strength ◽  
Stress Strain Curve ◽  
Physical Tests ◽  
Compression Condition

The mechanical properties of granite experiencing high temperatures under uniaxial compression condition were simulated in this paper. Numerically simulated stress-strain curve, peak stress, peak strain and the tangent elastic modulus were compared with the corresponding physical tests. Simulated results agree well with physical tests results, it is shown that Abaqus is suitable for the analysis of the temperature effect on rock fracture.

Mechanical Properties of Bentonite-Sand Mixtures Under Triaxial Stress Condition

1994 ◽  
Vol 353 ◽  
Author(s):  
M. Umedera ◽  
A. Fujiwara ◽  
N. Yasufuku ◽  
M. Hyodo ◽  
H. Murata
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Water Content ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Strength Properties ◽  
Compression Tests ◽  
Optimum Water Content ◽  
Triaxial Compression Tests ◽  
Optimum Water

AbstractA series of triaxial compression tests is being conducted under the drained condition on bentonite and sand mixtures, known as buffer, in saturated and optimum water content states to clarify the mechanical properties of the buffer.It was found that the mechanical properties of bentonite and sand mixtures are strongly influenced by water and bentonite contents: shear strength in a saturated state is less than that in an optimum water content state; shear strength decreases rapidly with increasing bentonite content. Strength properties are much dependent on confining pressure.

Experimental Study on Mechanical Properties of Jurassic Soft Rock in Shajihai Mining Area of Xinjiang

2013 ◽  
Vol 353-356 ◽  
pp. 20-23
Author(s):  
Xiao Lei Wang ◽  
Shun Xi Yan ◽  
Guang Can Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Compression Test ◽  
Mechanical Test ◽  
Triaxial Compression ◽  
Soft Rock ◽  
Mining Area ◽  
Surrounding Rock ◽  
Test Results ◽  
Support Design

According to the problemsof serious deformation of soft rock roadways and lack of system andcomprehensive study on surrounding rock characteristics and failure mechanismin Shajihai mining area, this paper carried out a series of mechanicalexperiments on the characteristics of surrounding rock in this area includinguniaxial compression test, triaxial compression test and water absorption propertiestest. Mechanical test results show that the compressive strength of surroundingrock of roadway is generally low, and mudstone compressive strength is thelargest which is 19.23 MPa, and compressive strength of the minimum is coalwhich is 11.32 MPa under natural condition. However sandstone and mudstone’sability of water absorbing is strong, and coal saturation strength issignificantly greater than that of mudstone and sandstone. Therefore, we shouldmake full use of the strength of coal in roadway layout and support design.

scholarly journals Experimental Study on the Influence of Moisture Content on the Mechanical Properties of Coal

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Mingxing Gao ◽  
Yongli Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Moisture Content ◽  
Uniaxial Compressive Strength ◽  
Poisson’S Ratio ◽  
Triaxial Compression ◽  
Test System ◽  
Poisson's Ratio ◽  
Compression Tests

Water injection in coal seams will lead to the increase of moisture content in coal, which plays an essential role in the physical and mechanical properties of coal. In order to study the influence of moisture content on the mechanical properties of soft media, the forming pressure (20 MPa) and particle size ratio (0-1 mm (50%), 1-2 mm (25%), and 2-3 mm (25%)) during briquette preparation were firstly determined in this paper. Briquettes with different moisture contents (3%, 6%, 9%, 12%, and 15%) were prepared by using self-developed briquettes. Uniaxial and triaxial compression tests were carried out using the RMT-150C rock mechanics test system. The results show that the uniaxial compressive strength and elastic modulus of briquette samples increase first and then decrease with the increase of briquette water, while Poisson’s ratio decreases first and then increases with the increase of briquette water. When the moisture content is around 9%, the maximum uniaxial compressive strength is 0.866 MPa, the maximum elastic modulus is 1.385 GPa, and Poisson’s ratio is at the minimum of 0.259. The compressive strength of briquettes increases with the increase of confining pressure. With the increase of moisture content, the cohesion and internal friction angle of briquettes first increased and then decreased.

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