The Experiment to Research the Mudstone Interbeds which Affect the Mechanical Characters of the Layered Rock Salt

2012 ◽  
Vol 226-228 ◽  
pp. 1279-1284
Author(s):  
De Yi Jiang ◽  
Xue Qin Fan ◽  
Tao Ren ◽  
Jie Chen ◽  
Song Ren
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compressive Strength ◽  
Rock Salt ◽  
Triaxial Compression ◽  
Salt Formation ◽  
Layered Rock ◽  
The Stability ◽  
Mechanic Property ◽  
Mechanical Characters

Since mudstone interlayer has a big influence on the mechanic property of layered rock salt, and in order to research its law, the mudstone which strength is lower than pure rock is used as a interlayer to make the regular layer of salt formation, then both the uniaxial and triaxial compression test are carried out on the layer of salt formation. The result indicates: (1) As the thickness of interlayer increases the uniaxial compressive strength and elastic modulus of layer type salt decrease. (2) On the condition that the thickness of interlayer does not change, the more the interlayer number, the stronger the uniaxial compressive strength. (3) If the total thickness of interlayer is stable and the interlayer number is same, then as the distance of interlayer increases the uniaxial compressive strength and elastic modulus of layer type salt decrease. The result provides practical value and theoretic basis on the further research of the mechanic property of layered rock soil and on the analysis of the stability of Karst underground salt cavity reservoir.

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.

scholarly journals Experimental Analysis of the Mechanical Properties and Resistivity of Tectonic Coal Samples with Different Particle Sizes

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2303
Author(s):  
Congyu Zhong ◽  
Liwen Cao ◽  
Jishi Geng ◽  
Zhihao Jiang ◽  
Shuai Zhang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compressive Strength ◽  
Coalbed Methane ◽  
Coal Sample ◽  
Fine Particles ◽  
Particle Sizes ◽  
Tectonic Coal

Because of its weak cementation and abundant pores and cracks, it is difficult to obtain suitable samples of tectonic coal to test its mechanical properties. Therefore, the research and development of coalbed methane drilling and mining technology are restricted. In this study, tectonic coal samples are remodeled with different particle sizes to test the mechanical parameters and loading resistivity. The research results show that the particle size and gradation of tectonic coal significantly impact its uniaxial compressive strength and elastic modulus and affect changes in resistivity. As the converted particle size increases, the uniaxial compressive strength and elastic modulus decrease first and then tend to remain unchanged. The strength of the single-particle gradation coal sample decreases from 0.867 to 0.433 MPa and the elastic modulus decreases from 59.28 to 41.63 MPa with increasing particle size. The change in resistivity of the coal sample increases with increasing particle size, and the degree of resistivity variation decreases during the coal sample failure stage. In composite-particle gradation, the proportion of fine particles in the tectonic coal sample increases from 33% to 80%. Its strength and elastic modulus increase from 0.996 to 1.31 MPa and 83.96 to 125.4 MPa, respectively, and the resistivity change degree decreases. The proportion of medium particles or coarse particles increases, and the sample strength, elastic modulus, and resistivity changes all decrease.

scholarly journals Degradation of Mechanical Behavior of Sandstone under Freeze-Thaw Conditions with Different Low Temperatures

2021 ◽  
Vol 11 (22) ◽  
pp. 10653
Author(s):  
Jingwei Gao ◽  
Chao Xu ◽  
Yan Xi ◽  
Lifeng Fan
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Energy Absorption ◽  
Uniaxial Compressive Strength ◽  
Dynamic Strength ◽  
Freezing Temperature ◽  
P Wave ◽  
Freeze Thaw ◽  
P Wave Velocity

This study investigated the effects of freezing temperature under freeze-thaw cycling conditions on the mechanical behavior of sandstone. First, the sandstone specimens were subjected to 10-time freeze-thaw cycling treatments at different freezing temperatures (−20, −40, −50, and −60 °C). Subsequently, a series of density, ultrasonic wave, and static and dynamic mechanical behavior tests were carried out. Finally, the effects of freezing temperature on the density, P-wave velocity, stress–strain curves, static and dynamic uniaxial compressive strength, static elastic modulus, and dynamic energy absorption of sandstone were discussed. The results show that the density slightly decreases as temperature decreases, approximately by 1.0% at −60 °C compared with that at 20 °C. The P-wave velocity, static and dynamic uniaxial compressive strength, static elastic modulus, and dynamic energy absorption obviously decrease. As freezing temperature decreases from 20 to −60 °C, the static uniaxial compressive strength, static elastic modulus, dynamic strength, and dynamic energy absorption of sandstone decrease by 16.8%, 21.2%, 30.8%, and 30.7%, respectively. The dynamic mechanical behavior is more sensitive to the freezing temperature during freeze-thawing cycling compared with the static mechanical behavior. In addition, a higher strain rate can induce a higher dynamic strength and energy absorption.

Comparative experimental study on physical and mechanical properties of quartz sandstone after water-cooling and natural-cooling under high temperature

2021 ◽  
pp. qjegh2020-181
Author(s):  
Haopeng Jiang ◽  
Annan Jiang ◽  
Fengrui Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compressive Strength ◽  
Heating Temperature ◽  
Physical And Mechanical Properties ◽  
P Wave ◽  
Water Cooling ◽  
Average Value ◽  
Cooling Methods

Experimental tests were conducted to study the influence of natural cooling and water cooling on the physical and mechanical properties of quartz sandstone. This study aims to understand the effect of different cooling methods on the physical and mechanical properties of quartz sandstone (such as mass, volume, density, P-wave velocity, elastic modulus, uniaxial compressive strength, etc.). The results show that the uniaxial compressive strength (UCS) and elastic modulus(E) of the specimens cooled by natural-cooling and water-cooling decrease with heating temperature. At 800℃, after natural cooling and water cooling, the average value of UCS decreased by 34.65% and 57.90%, and the average value of E decreased by 87.66% and 89.05%, respectively. Meanwhile, scanning electron microscope (SEM) images were used to capture the development of microcracks and pores within the specimens after natural-cooling and water-cooling, and it was found that at the same temperature, water cooling treatment was more likely to cause microcracks and pores, which can cause more serious damage to the quartz sandstone. These results confirm that different cooling methods have different effects on the physical and mechanical properties of quartz sandstone, and provide a basis for the stability prediction of rock mass engineering such as tunnel suffering from fire.

Numerical investigation of micro-cracking behavior of brittle rock containing a pore-like flaw under uniaxial compression

2020 ◽  
Vol 29 (10) ◽  
pp. 1543-1568 ◽  
Author(s):  
Louis Ngai Yuen Wong ◽  
Jun Peng
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Numerical Model ◽  
Crack Initiation ◽  
Uniaxial Compression ◽  
Uniaxial Compressive Strength ◽  
Early Stage ◽  
Brittle Rock ◽  
Cracking Behavior ◽  
Cracking Process

Pore-like flaws, which are commonly encountered in brittle rock, play an important role in the engineering performance of structures constructed in or on rock. Experimental and numerical investigations of micro-cracking mechanism of rock containing a pore-like flaw can enhance our knowledge of rock damage/failure from a microscopic view. In this study, the influences of a two-dimensional circular pore-like flaw with respect to its diameter and position on the strength and micro-cracking behavior of brittle rock under uniaxial compression are numerically investigated. The results reveal that the strength and elastic modulus are significantly affected by the diameter and position in the pore. The uniaxial compressive strength and elastic modulus of the numerical model with a pore diameter of 15.44 mm located in the center of the model are found to decrease by 58.6% and 56.4% respectively when compared with those of the intact model without a pore. As the pore position varies while the porosity remains unchanged, the simulated uniaxial compressive strength and elastic modulus are also found to be generally smaller than those of the intact model without a pore. When a pore-containing numerical model is loaded, the micro-cracks are found to mostly initiate at the top and bottom of the pore, due to the local tensile stress increase. The simulation results of the early-stage micro-cracking process and stress distribution are in a generally good agreement with the analytical solution obtained from the Kirsch equations. The grain-based model used in this study can not only study the crack initiation on the boundary of the pore but also provide a convenient means to analyze and visualize the temporal and spatial micro-cracking process after the crack initiation, which accounts for the variations in the simulated strength and modulus satisfactorily from a micro-cracking view.

Effect of Sintering Temperature on Porous Structures and Mechanical Properties of Ti-39Nb-6Zr Alloys

2016 ◽  
Vol 848 ◽  
pp. 532-537 ◽  
Author(s):  
Ye Shao ◽  
Xiao Yun Song ◽  
Wen Jun Ye ◽  
Song Xiao Hui ◽  
Yang Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Sintering Temperature ◽  
Porous Structures ◽  
Powder Metallurgy Technique ◽  
Porous Ti ◽  
The Stability ◽  
Surrounding Bone ◽  
Compressive Tests

Titanium and its alloys have been widely used as implants replacing hard human tissues in biomedical fields. To improve the stability of implants in the surrounding bone tissues, the materials with porous structures were fabricated. In this paper powder metallurgy technique was employed to fabricate porous Ti-39Zr-6Nb (wt.%) alloys. The porous structures and mechanical properties of the porous alloys were examined by scanning electron microscopy (SEM) and compressive tests. The results showed that with increasing the sintering temperature the porosity of the alloys decreased and the compressive strength and the elastic modulus increased. The porosity of the alloys was in the range from 20.8% to 23.2%, and the pore sizes mostly centered in 10~30μm. The compressive strength and the elastic modulus were in the range from 110.4 to 292.4MPa and 4.7 to 12.4GPa respectively, which was close to human bone.

Sign in / Sign up

Export Citation Format

Share Document