Dynamic Properties of Intact Rock Samples Subjected to Cyclic Loading under Confining Pressure Conditions

2011 ◽  
Vol 44 (5) ◽  
pp. 629-634 ◽  
Author(s):  
EnLong Liu ◽  
Siming He ◽  
Xinhua Xue ◽  
Jin Xu
Keyword(s):  
Cyclic Loading ◽  
Dynamic Properties ◽  
Confining Pressure ◽  
Intact Rock ◽  
Rock Samples

scholarly journals Variation in Micro-Pores During Dynamic Consolidation and Compression of Soft Marine Soil

2021 ◽  
Vol 9 (7) ◽  
pp. 750
Author(s):  
Chen-Xiang Dai ◽  
Qiong-Fang Zhang ◽  
Shao-Heng He ◽  
An Zhang ◽  
Hua-Feng Shan ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Pore Structure ◽  
Dynamic Properties ◽  
Confining Pressure ◽  
Cyclic Stress ◽  
Test Results ◽  
Dynamic Consolidation ◽  
Confining Pressures ◽  
Stress Ratios ◽  
Marine Soil

In this study, to explore the microstructure deformation mechanism of marine soft marine soil under cyclic loading, we analyzed the dynamic properties of soft marine soil under cyclic loading via dynamic consolidation compression testing. Then, using Image-Pro Plus (IPP) 6.0 image analysis software, and according to the dynamic consolidation compression test results and the images from a scanning electron microscope (SEM), we determined the weakening effect of soft soils under different consolidation confining pressures, different cyclic stress ratios, and different over-consolidation ratios. After dynamic consolidation and compression, the pore structure of undisturbed soft marine soil tends to compact, the degree of soil particle fragmentation intensifies, small pores increase, large pores decrease, the pores become more regular, and the distribution of pores is directional. Subsequently, for undisturbed soft marine soil, the higher the consolidated confining pressure, cyclic dynamic stress ratio, and over-consolidation ratio, the greater the damage to the pore structure, and the more obvious the structural weakening effect exhibited under cyclic loading.

Study on the Dynamic Performance of Asphalt Concrete under Passive Confined Pressure

2012 ◽  
Vol 226-228 ◽  
pp. 1755-1759
Author(s):  
Hua Zhang ◽  
Fei Li ◽  
Yu Wei Gao
Keyword(s):  
Elastic Modulus ◽  
Asphalt Concrete ◽  
Poisson Ratio ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Dynamic Strength ◽  
Confining Pressure ◽  
Mechanical Behaviors ◽  
One Dimensional ◽  
Stress States

An improved passive confining pressure SHPB method was used to study the dynamic mechanical behaviors of asphalt concrete under quasi-one dimensional strain state. The effect of confining jacket material and its geometrical sizes on the confining pressure were discussed. The dynamic strength, dynamic modulus of elasticity and dynamic Poisson ratio of asphalt concrete were obtained. The influential rules of confining pressure on the dynamic properties were studied by comparing the stress-strain curves of asphalt concrete under different stress states. The study found that passive confining greater impact on the strength of asphalt concrete than elastic modulus and Poisson ratio, but the elastic modulus improved with the increase of confining pressure.

A Study on Dynamic Properties of Cement-Stabilized Soils

2011 ◽  
Vol 243-249 ◽  
pp. 2050-2054 ◽  
Author(s):  
Pei Hsun Tsai ◽  
Sheng Huoo Ni
Keyword(s):  
Shear Modulus ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Test Results ◽  
Resonant Column Test ◽  
Stabilized Soil ◽  
Shearing Strain ◽  
Relationship Of ◽  
The Relationship

In this paper the dynamic property (shear modulus and damping ratio) of cement-stabilized soil is studied with using the resonant column test. The amount of cement admixed, the magnitude of confining pressure, and shearing strain amplitude are the parameters considered. Test results show that the maximum shear modulus of cement-stabilized soil increases with increasing confining pressure, the minimum damping ratio decreases with increasing confining pressure. The shear modulus of cement-stabilized soil decreases with increasing shearing strain while the damping ratio increases with increasing shearing strain. In the paper the relationship of shear modulus versus shearing strain is fitted into the Ramberg-Osgood equations using regression analysis.

scholarly journals Characterization of the Dynamic Properties of Clay–Gravel Mixtures at Low Strain Level

2020 ◽  
Vol 12 (4) ◽  
pp. 1616 ◽  
Author(s):  
Xianwen Huang ◽  
Aizhao Zhou ◽  
Wei Wang ◽  
Pengming Jiang
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Mechanical Performance ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Strain Level ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Gravel Content

In order to support the dynamic design of subgrade filling engineering, an experiment on the dynamic shear modulus (G) and damping ratio (D) of clay–gravel mixtures (CGMs) was carried out. Forty-two groups of resonant column tests were conducted to explore the effects of gravel content (0%, 10%, 20%, 30%, 40%, 50%, and 60%, which was the mass ratio of gravel to clay), gravel shape (round and angular gravels), and confining pressure (100, 200, and 300 kPa) on the dynamic shear modulus, and damping ratio of CGMs under the same compacting power. The test results showed that, with the increase of gravel content, the maximum dynamic shear modulus of CGMs increases, the referent shear strain increases linearly, and the minimum and maximum damping ratios decrease gradually. In CGMs with round gravels, the maximum dynamic shear modulus and the maximum damping ratio are greater, and the referent shear strain and the minimum damping ratio are smaller, compared to those with angular gravels. With the increase of confining pressure, the maximum dynamic shear modulus and the referent shear strain increase nonlinearly, while the minimum and maximum damping ratios decrease nonlinearly. The predicting equation for the dynamic shear modulus and the damping ratio of CGMs when considering confining pressure, gravel content, and shape was established. The results of this research may put forward a solid foundation for engineering design considering low-strain-level mechanical performance.

scholarly journals Acoustic Emission Simulation on Coal Specimen Subjected to Cyclic Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Huiqiang Duan ◽  
Depeng Ma
Keyword(s):  
Numerical Simulation ◽  
Acoustic Emission ◽  
Cyclic Loading ◽  
Confining Pressure ◽  
Rock Masses ◽  
Coal Specimen ◽  
Cycle Number ◽  
Confining Pressures ◽  
Unloading Rate ◽  
Ae Counts

The damage and failure state of the loaded coal and rock masses is indirectly reflected by its acoustic emission (AE) characteristics. Therefore, it is of great significance to study the AE evolution of loaded coal and rock masses for the evaluation of damage degree and prediction of collapse. The paper mainly represents a numerical simulation investigation of the AE characteristics of coal specimen subjected to cyclic loading under three confining pressures, loading-unloading rates, and valley stresses. From the numerical simulation tests, the following conclusions can be drawn: (1) The final cycle number of coal specimen subjected to cyclic loading is significantly influenced by the confining pressure, followed the valley stress. With the increase in confining pressure or valley stress, the cycle number tends to increase. However, the loading-unloading rate has a little influence on it. (2) The AE counts of coal specimen subjected to cyclic loading are greatly influenced by the confining pressure and the valley stress. With the increase in the confining pressure, the cumulative AE counts at the 1st cycle tend to increase but decrease at a cycle before failure; with the decrease in the valley stress, the cumulative AE counts per cycle increase in the relatively quiet phase. However, the loading-unloading rate has a little influence on it. (3) The failure mode of coal specimen subjected to cyclic loading is significantly influenced by the confining pressure. Under the uniaxial stress state, there is an inclined main fractured plane in the coal specimen, under the confining pressures of 5 and 10 MPa, the coal specimen represents dispersion failure. The loading-unloading rate and valley stress have little influence on it. (4) The AE ratio is proposed, and its evolution can better reflect the different stages of coal specimen failure under cyclic loading. (5) The influence of confining pressure on the broken degree of coal specimen subjected to cyclic loading is analyzed, and the higher the confining pressure, the more broken the failed coal specimen.

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