How I developed a true triaxial rock testing machine

2012 ◽  
pp. 155-174
Keyword(s):  
Testing Machine ◽  
True Triaxial ◽  
Rock Testing

scholarly journals Unloading Mechanics and Energy Characteristics of Sandstone under Different Intermediate Principal Stress Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yingjie Zhang ◽  
Jiangteng Li ◽  
Gang Ma ◽  
Shuangfei Liu
Keyword(s):  
Testing Machine ◽  
Strength Criterion ◽  
Intermediate Principal Stress ◽  
Loading Test ◽  
Energy Characteristics ◽  
True Triaxial ◽  
Triaxial Strength ◽  
Rock Testing ◽  
Cubic Polynomial ◽  
Loading And Unloading

The TRW-3000 true triaxial rock testing machine was used to conduct loading and unloading tests of sandstone under different σ 2 , and the true triaxial lateral unloading mechanics and energy characteristics of sandstone under different σ 2 were studied. The experimental results show the following: (1) compared with the results of the loading test, the peak strength of the sandstone under the unloading σ 3 path is reduced, the unloading direction has obvious expansion and deformation, and the amount of expansion increases significantly with the increase of σ 2 ; sudden brittle failure occurs at the end of unloading. E gradually decreases with the increase of H, and it performs well to use the cubic polynomial to fit the curve of E-H. (2) The Mogi–Coulomb strength criterion can accurately describe the true triaxial strength characteristics of sandstone under loading and unloading conditions. Compared with the results of the loading test, the values of c and φ obtained based on this criterion under the unloading σ 3 path are reduced. (3) Under the condition of unloading σ 3 , U, U e , and U d , when the specimen is broken, are all linearly positively correlated with σ 2 . U d increases nonlinearly with the increase of H, and as σ 2 increases, the slope of the U d -H curve becomes larger, and the specimen consumes more energy under the same unloading amount. Most of the energy absorbed by the specimen under the unloading σ 3 path is converted into U e , but as σ 2 increases, U d   / U increases, and the energy consumed when the specimen is broken is greater.

scholarly journals New method for true-triaxial rock testing

1997 ◽  
Vol 34 (3-4) ◽  
pp. 330.e1-330.e14 ◽  
Author(s):  
W.R. Wawersik ◽  
L.W. Carlson ◽  
D.J. Holcomb ◽  
R.J. Williams
Keyword(s):  
New Method ◽  
True Triaxial ◽  
Rock Testing

The Test of Dynamic Characteristics of Concrete under Biaxial Compression State

2013 ◽  
Vol 859 ◽  
pp. 177-181
Author(s):  
Jin Sheng Lei ◽  
Fei Liu ◽  
Gang Peng ◽  
Min Lei
Keyword(s):  
Stress State ◽  
Dynamic Characteristics ◽  
Dynamic Compression ◽  
Testing Machine ◽  
Peak Stress ◽  
Biaxial Stress ◽  
Biaxial Compression ◽  
Peak Strain ◽  
Compression Tests ◽  
True Triaxial

Concrete structure in reality mostly in complicated stress state, dynamic characteristics and static characteristics under earthquakes and other dynamic loads are very different. For a further understanding of the dynamic characteristics of the concrete, true triaxial testing machine system was used to the C30 concrete at different strain rates and different side of the cube concrete specimens stress biaxial dynamic compression tests. Biaxial stress state concrete elasticity modulus, peak stress, peak strain, was obtained by the experimental study, and carries on the comparative analysis. Results show that: the dynamic characteristics of concrete under biaxial compression state of concrete and uniaxial condition are very different.

scholarly journals Strength behavior of plain cement concrete subjected to true triaxial compression

2018 ◽  
Vol 45 (3) ◽  
pp. 179-196 ◽  
Author(s):  
Saurav Rukhaiyar ◽  
Gaurav Sajwan ◽  
Narendra Kumar Samadhiya
Keyword(s):  
Compression Test ◽  
Triaxial Compression ◽  
Testing Machine ◽  
Failure Criteria ◽  
Triaxial Compression Test ◽  
Cement Concrete ◽  
Principal Stresses ◽  
True Triaxial ◽  
Strength Concrete ◽  
True Triaxial Compression

True triaxial compression test was conducted on 100 mm × 100 mm × 100 mm cubical sample of plain cement concrete using the true triaxial testing machine. A total of 30 tests were conducted on two concrete mixes having characteristic strengths of 24.39 MPa and 34.67 MPa. The minor and intermediate principal stresses were varied from 2.5 MPa to 10 MPa and 2.5 MPa to 30 MPa respectively. The samples were loaded until failure under the stress rate of 1 MPa/min. The failure mode and direction of fracture planes were observed carefully. It was observed that the ratio of intermediate and minor principal stress had an incremental effect on the strength of the concrete. The results obtained from our experimental study as well as the true triaxial compression test data published in literature has been used to conduct a quantitative evaluation of three commonly used failure criteria presented for the concrete. The three failure criteria considered are Drucker-Prager (DP) criterion, Bresler-Pester (BP) criterion, and Hsieh-Ting-Chen (HTC) criterion. It was observed that for the normal strength concrete, the HTC criterion predicts the strength with least error while for the high strength concrete, the DP criterion gives better predictions. Overall the DP and BP criteria underestimate the strength while the HTC criterion overestimates.

scholarly journals The Static Breaking Technique for Sustainable and Eco-Environmental Coal Mining

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Hao Bing-yuan ◽  
Huang Hui ◽  
Feng Zi-jun ◽  
Wang Kai
Keyword(s):  
Growth Rate ◽  
Acoustic Emission ◽  
Testing Machine ◽  
Vertical Direction ◽  
Rock Breaking ◽  
Extended Model ◽  
True Triaxial ◽  
Hard Roof ◽  
Expansion Time ◽  
Applied Forces

The initiating explosive devices are prohibited in rock breaking near the goaf of the highly gassy mine. It is effective and applicable to cracking the hard roof with static cracking agent. By testing the static cracking of cubic limestone (size:200×200×200 mm) with true triaxial rock mechanics testing machine under the effect of bidirectional stress and by monitoring the evolution process of the cracks generated during the acoustic emission experiment of static cracking, we conclude the following: the experiment results of the acoustic emission show that the cracks start from the lower part of the hole wall until they spread all over the sample. The crack growth rate follows a trend of “from rapidness to slowness.” The expansion time is different for the two bunches of cracks. The growth rates can be divided into the rapid increasing period and the rapid declining period, of which the growth rate in declining period is less than that in the increasing period. Also, the growth rate along the vertical direction is greater than that of the horizontal direction. Then the extended model for the static cracking is built according to the theories of elastic mechanics and fracture mechanics. Thus the relation formula between the applied forces of cracks and crack expansion radius is obtained. By comparison with the test results, the model proves to be applicable. In accordance with the actual geological situation of Yangquan No. 3 Mine, the basic parameters of manpower manipulated caving breaking with static crushing are settled, which reaps bumper industrial effects.

Theoretical, Numerical and Experimental Study of Deformation and Failure Process of Rock

2004 ◽  
Vol 261-263 ◽  
pp. 1529-1534 ◽  
Author(s):  
Chun An Tang ◽  
Chien Hsin Yang ◽  
Tao Xu ◽  
Tian Hong Yang
Keyword(s):  
Numerical Simulation ◽  
Experimental Study ◽  
Theoretical Analysis ◽  
Failure Process ◽  
Testing Machine ◽  
Experimental Tests ◽  
Deformation And Failure ◽  
Rock Testing ◽  
Numerical Tool ◽  
Rock Specimens

In this paper, theoretical constitutive model, numerical tool, viz., RFPA code and servo-type testing machine, viz., RMT-150B rock testing systems were briefly described, respectively. Then, based on theoretical analysis, numerical simulation and experimental tests for rock specimens in uniaxial compression, the relations and differences between theoretical, numerical and experimental results, especially the complete stress-strain curves, were contrastively analyzed and investigated. The reason for these relations and differences among results was also proposed in this paper.

Testing Machine at Watertown Arsenal, Mass

1886 ◽  
Vol 22 (548supp) ◽  
pp. 8753-8754
Author(s):  
J. E. Howard
Keyword(s):  
Testing Machine
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