Influence of Loading Rate on Uniaxial Compression Test of Rock Specimen with Random Joints

2011 ◽  
Vol 396-398 ◽  
pp. 217-220
Author(s):  
Bing Xie ◽  
Jin Jun Guo ◽  
Xiang Xia

Numerical specimens with ramdom joints is established by particle flow code PFC2D and uniaxial compression tests are conducted under three different loading rate. Studies have shown that strength of uniaxial compression are all increased with the loading rate no matter what specimen is complete or with random joints. The sensitivity of changes of uniaxial compressive strength of specimen with random joints decreases with increasing of the loading rate.

2011 ◽  
Vol 418-420 ◽  
pp. 848-850
Author(s):  
Bing Xie ◽  
Li Guo ◽  
Xiang Xia

Numerical specimens with ramdom holes is established by particle flow code PFC2D and uniaxial compression tests are conducted. Studies have shown that the uniaxial compressive strength of the specimen accelerated decline while the porosity increasing uniformly. With the increasing of the porosity,the plastic of the specimen increases.


2012 ◽  
Vol 446-449 ◽  
pp. 3810-3813
Author(s):  
Bing Xie ◽  
Huai Feng Tong ◽  
Xiang Xia

Numerical specimens with single-hole is established by particle flow code PFC2D and uniaxial compression tests are conducted. Studies have shown that uniaxial compressive strength of specimen with single hole is less than complete specimens. As the holes move to the end of specimen, the uniaxial compressive strength first increases and then tends to decrease.


2012 ◽  
Vol 232 ◽  
pp. 24-27
Author(s):  
Zong Zhan Li ◽  
Jun Lin Tao ◽  
Yi Li

This paper makes the acoustic emission of granite under uniaxial compression and splitting tensile test by electro-hydraulic testing machine and AE .We studied the relationship of uniaxial compressive strength and splitting tensile strength with the loading rate and AE characteristics of granite .The results show that uniaxial compressive strength and peak strain raise with loading rate, the AE energy gradually increases and get maximum in the 30% of the peak stress in the process of uniaxial compression test, and in the splitting tensile AE energy generates in the initial loading and gets maximum when the granite brittle fracture.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhixi Liu ◽  
Guangming Zhao ◽  
Xiangrui Meng ◽  
Ruofei Zhang ◽  
Dong Chunliang ◽  
...  

To investigate the energy evolution characteristics of sandstone under static-quasi-dynamic loading rates (1.0 × 10−3, 5.0 × 10−3, 1.0 × 10−2, 5.0 × 10−2, and 1.0 × 10−1 mm/s), the uniaxial compression tests, the uniaxial cyclic loading-unloading tests, and the uniaxial incrementally cyclic loading-unloading tests were conducted under five different loading rates. Through analysis of the elastic energy of the uniaxial cyclic loading-unloading test and the uniaxial incremental cyclic loading-unloading test, show that the impact of the loading rate and the cycle numbers on the elastic energy is less. Hence, we can deem that when the loads of the uniaxial incremental cyclic loading-unloading test and the uniaxial compression test are equal, the elastic energy of the two also equals. The energy in the uniaxial compression tests analyzed by the uniaxial incrementally cyclic loading-unloading test show that elastic energy increased linearly when the input energy increased under different loading rates. Through the linear energy storage law and the uniaxial incremental cyclic loading and unloading test, it is possible to analyze the energy in the uniaxial compression test at any loading rates. The results show that the greater the loading rate, the greater the peak elastic energy and peak input energy. But when the load is equal, the greater the loading rate, the smaller the input energy and elastic energy. Compared with traditional methods, the new energy analysis method is accurate and simple. Meanwhile, based on energy dissipation, the damage of rock during uniaxial compression tests was studied.


2012 ◽  
Vol 594-597 ◽  
pp. 816-819
Author(s):  
Zhi Hao Liu ◽  
Chuan Xiao Liu ◽  
Dong Chen Huang ◽  
Long Wang

Through the uniaxial compression test, the mechanical properties of different placements of iron wire cement mortar, e.g. compressive strength and elastic modulus, were studied, and the mass ratios of cement, sands and water influencing the mechanical properties were put forward, which provided the experimental results for reference for the wide use of the iron wire cement mortar material. From the study it is gained that: (1) The best placement of the iron wires in cement mortar is horizontal. (2) The best mass ratio of the cement, sands and water is 1:4.70:0.81.


2018 ◽  
Vol 22 (1) ◽  
pp. 5-13
Author(s):  
Dariusz Błażejczak ◽  
Kinga Śnieg ◽  
Małgorzata Słowik

AbstractThe objective of this paper was to compare the results of soil material compaction carried out with the use of the Proctor and uniaxial compression tests in order to find relations between these methods. Soil material in the form of loose mass was collected from the layer deposited at the depth from 35 to 60 cm in order to determine its typical properties (textural group, density of solid particles, humus content, reaction, plastic and liquid limits) and in order to compact it in the Proctor apparatus and in the uniaxial compression test. Results of both tests were used for construction of regression models reflecting the course of the unit stress (Pρdp), necessary to generate compaction equal to the dry density of solid particles obtained in the Proctor apparatus (ρdp) in relation to the sample moisture (ws). It was stated that the stress value Pρdp on the soil sample in the uniaxial compression test depends significantly on ws. It was proved that for the purpose of comparing the results of both tests, the uniaxial stress of samples must be performed in conditions of their lateral expansion. It was also proved that the use of the uniaxial test with possible lateral expansion of soil with a model sample, a diameter of which is 100 and the height is 30 mm, one may determine the obtained compaction with the use of the plate movement value.


2011 ◽  
Vol 261-263 ◽  
pp. 1393-1400
Author(s):  
Ji Liang Zhang ◽  
Chang Hong Li

Based on uniaxial compression test, the mechanical properties and acoustic emission characteristics of rock had been obtained, including the relationship between AE and time, AE and stress level, and so on, in the whole process of rock failure. Research shows AE rate of rock has the subparagraph features obviously. There are three obvious AE sections for the higher strength elastic-brittle rock: First section is compaction stage, corresponding stress is 10% of compressive strength of rock; Second section is crack-development stage, corresponding stress is 80% of compressive strength; Third section is rupture stage, corresponding stress is the compressive strength. Furthermore, AE signals for the rupture stage is strongest. The law is still correct in cycle loading conditions. However, the subparagraph phenomenon isn’t clear for elastic-plastic rock, and the AE peak is lagging behind the ultimate strength of rock, the AE signal in the decline stage of strength is the most intensive and strong. The lagging phenomenon is due to X-shear rupture model of soft rock. The significant stress concentration in cone tip between the two relative extrusion cones leads to local rock broken seriously. Then, many acoustic signals have been observed.


2011 ◽  
Vol 137 ◽  
pp. 140-143
Author(s):  
Bing Xie ◽  
Yun Ling Ma ◽  
Xiang Xia

Numerical specimens with two pre-existing flaws is established by using particle flow code PFC2D and by changing the relative position of the pre-existing flaws different rock bridge angle is obtained. Though the uniaxial compression test of specimens with different rock bridge angle , it can be found that rock bridge angle have a great impact on the mode of crack propagation of specimen. The different relative position between the two pre-existing flaws led to different levels of stress shielding effect under the axial force, and it is most likely to damage when the two pre-existing flaws are about overlap.


Author(s):  
Isaac Iglesias ◽  
Mayra Jiménez ◽  
Andrea M. Gallardo ◽  
Edward E. Ávila ◽  
Vivian Morera ◽  
...  

In this work, we report the mechanical properties of an alternative material based on a mixture of natural clay and ferruginous sand in pellet form for CO2 capture. These raw materials were collected from Ecuador, and they contain iron and titanium oxides from volcanic origin. To evaluate the effect of the sand content on the mechanical properties of pellets, the samples were manually prepared with 0 (control sample), 15, and 25 wt.% sand contents and analyzed using free-fall drop impact and uniaxial compression tests. The uniaxial compression test was carried out under three conditions: using sieved sand, using sand without sieving, and under wet conditions. The sand contents caused the drop number to decrease in the free-fall drop impact test. From the uniaxial compression test, the compressive strength, elastic modulus, and toughness were calculated. The elastic modulus showed a better performance for samples with lower porosity. The compressive strength demonstrated higher values for samples with 15 wt.% sand contents than for samples with the other sand contents. The toughness values did not significantly change. It was evidenced that the porosity, mineral composition, and humidity exerted an influence during the mechanical tests. The mineral phases were analyzed by X-ray diffraction, and quantitative analysis based on whole-powder-pattern fitting revealed that the iron and titanium oxide contents increased as the concentration of sand in the pellets increased.


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