Strength and Failure Behavior of Coal Specimens with Different Diameters Under Conventional Triaxial Compression

2022 ◽  
pp. 473-501
Author(s):  
Sheng-Qi Yang
Keyword(s):  
Triaxial Compression ◽  
Failure Behavior ◽  
Conventional Triaxial Compression ◽  
Different Diameters

Mechanical and cracking behavior of granite containing two coplanar flaws under conventional triaxial compression

2018 ◽  
Vol 28 (4) ◽  
pp. 590-610 ◽  
Author(s):  
Yan-Hua Huang ◽  
Sheng-Qi Yang
Keyword(s):  
Triaxial Compression ◽  
Three Dimensional ◽  
Damage Threshold ◽  
Confining Pressure ◽  
Crack Coalescence ◽  
Failure Behavior ◽  
Shear Cracks ◽  
Cracking Behavior ◽  
Conventional Triaxial Compression ◽  
Triaxial Compressive Strength

Flaws widely exist in rock mass, which significantly influences the strength and failure behavior of rock. The study of the flaw effect on the mechanical and cracking behavior is important to predict the unstable failure of fractured rock engineering. However, three-dimensional crack propagation behavior of real rock containing preexisting flaws under triaxial compression has been rarely studied. To increase the understanding of crack coalescence behavior, a series of laboratory conventional triaxial compression experiments were carried out on granite specimens containing two coplanar three-dimensional flaws. On the basis of experimental results, the effects of flaw angle and confining pressure on the strength properties of granite specimens were analyzed. As the flaw angle increased from 30° to 60° and the confining pressure increased from 0 to 30 MPa, the triaxial compressive strength and crack damage threshold of granite specimen increased. The cohesion and internal friction angle of preflawed granite specimen increased with increasing flaw angle. And then, X-ray micro-CT scanning technique was used to investigate the internal fracture characteristic of granite specimen. Four typical crack coalescence modes were identified in this experiment, i.e. no coalescence, two types of indirect coalescence, and shear coalescence. Under uniaxial compression, cracks from the tips of the flaws led to the specimen failure under tension, while under higher confining pressure, shear cracks and antiwing cracks were dominant.

A new nonlinear empirical strength criterion for rocks under conventional triaxial compression

2021 ◽  
Vol 28 (5) ◽  
pp. 1448-1458
Author(s):  
Shi-jie Xie ◽  
Hang Lin ◽  
Yi-fan Chen ◽  
Yi-xian Wang
Keyword(s):  
Triaxial Compression ◽  
Strength Criterion ◽  
Conventional Triaxial Compression

scholarly journals Researches on the Constitutive Models of Artificial Frozen Silt in Underground Engineering

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yugui Yang ◽  
Feng Gao ◽  
Hongmei Cheng ◽  
Yuanming Lai ◽  
Xiangxiang Zhang
Keyword(s):  
Mechanical Characteristic ◽  
Stress Level ◽  
Strain Softening ◽  
Triaxial Compression ◽  
High Stress ◽  
Constitutive Models ◽  
Confining Pressure ◽  
Frozen Soil ◽  
Conventional Triaxial Compression ◽  
Shear Process

The researches on the mechanical characteristic and constitutive models of frozen soil have important meanings in structural design of deep frozen soil wall. In the present study, the triaxial compression and creep tests have been carried out, and the mechanical characteristic of frozen silt is obtained. The experiment results show that the deformation characteristic of frozen silt is related to confining pressure under conventional triaxial compression condition. The frozen silt presents strain softening in shear process; with increase of confining pressure, the strain softening characteristic gradually decreases. The creep curves of frozen silt present the decaying and the stable creep stages under low stress level; however, under high stress level, once the strain increases to a critical value, the creep strain velocity gradually increases and the specimen quickly happens to destroy. To reproduce the deformation behavior, the disturbed state elastoplastic and new creep constitutive models of frozen silt are developed. The comparisons between experimental results and calculated results from constitutive models show that the proposed constitutive models could describe the conventional triaxial compression and creep deformation behaviors of frozen silt.

A Simple and Practicable Approach on Implementing for the Reduced Triaxial Extension by the Conventional Triaxial Apparatus

2011 ◽  
Vol 250-253 ◽  
pp. 2089-2092
Author(s):  
Rong Jian Li ◽  
Xi An Li ◽  
Gao Feng Che ◽  
Wen Zheng ◽  
Wen Jun Chen
Keyword(s):  
Triaxial Compression ◽  
Stress Path ◽  
Test Results ◽  
Triaxial Apparatus ◽  
Eolian Sand ◽  
Conventional Triaxial Compression ◽  
The Difference ◽  
Shear Behaviors ◽  
The Impact ◽  
Triaxial Extension

Stress path is one of the very important factors of soil strength. It is significant to study the strength and reveal the importance of the impact of sand in different stress path conditions. Firstly, an ameliorating approach on implementing for the reduced triaxial extension by the conventional triaxial apparatus was discussed. Then, In order to study shear behaviors of the eolian sand under different stress path, two monotonic shearing tests with the conventional triaxial compression and the reduced triaxial extension stress path were performed and analyzed. The test results not only indicate that the amelioration on conventional triaxial apparatus is simple, practicable and inexpensive, but also reveal the difference of strength’s parameter between the reduced triaxial extension and conventional triaxial compression stress path. In sum, the stress path has important effect on the strength of the eolian sand.

Experimental Study on the Influence of Temperature on Shale Mechanical Properties under Conventional Triaxial Compression

2011 ◽  
Vol 250-253 ◽  
pp. 1452-1455 ◽  
Author(s):  
Lu Bo Meng ◽  
Tian Bin Li ◽  
Liang Wen Jiang ◽  
Hong Min Ma
Keyword(s):  
Mechanical Properties ◽  
Thermal Stress ◽  
Elastic Modulus ◽  
High Temperature ◽  
Poisson’S Ratio ◽  
Triaxial Compression ◽  
Poisson's Ratio ◽  
Influence Of Temperature ◽  
Conventional Triaxial Compression ◽  
Influence Of Temperature On

High temperature conventional triaxial compression test of shale are carried out by the MTS815 servo-controlled testing machine, based on the experimental results, the relationships between temperature and shale peak strength, elastic modulus, Poisson's ratio, cohesion, internal friction angle are investigated. Although the experimental results are discrete comparatively, the general law is obvious. When the confining pressure imposed on shale is constant and the temperature changes form 25°C to 120°C, with the increasing of the temperature, the triaxial compression strength, shear strength gradually increase, while average elastic modulus, Poisson's ratio has a slightly decrease. The thermal stress generated by the high temperature plays a role to accommodate the deformation and the function of preventing crack propagation, thus the bearing capacity of shale samples are strengthened. But the influence of temperature on shale mechanical properties mutates when the temperature is at 80°C. Shale peak strength dramatically decreased, average elastic modulus decreased slightly, and Poisson's ratio also increased slightly, which indicated that at 80°C, different thermal expansivity of mineral particles of shale may cause cross-grain boundary thermal expansion incongruous, creating additional thermal stress, thus the sample’s bearing capacity decreased.

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