scholarly journals Experimental Study on the Deformation and Strength Characteristics of Saturated Clay under Cyclic Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jian Zhang ◽  
Yangguang Sun ◽  
Jiuting Cao
Keyword(s):  
Shear Stress ◽  
Vibration Frequency ◽  
Failure Strain ◽  
Dynamic Strength ◽  
Cyclic Stress ◽  
Strength Characteristics ◽  
Dynamic Strain ◽  
Cyclic Stress Ratio ◽  
Saturated Clay ◽  
Deformation And Strength Characteristics

The deformation and strength characteristics of saturated clay are studied through a cyclic triaxial test of clay in the Wenchuan earthquake area. Specifically, the effects of cyclic stress ratio, initial shear stress, and vibration frequency on the dynamic characteristics of saturated clay are analysed. Results show a failure strain in the dynamic strain development of saturated clay. Before the failure strain, the dynamic strain of soil develops slowly. After the failure strain, the soil strain increases sharply and leads to failure. Under the same confining pressure, the failure strain produced by different cyclic stress ratios has a linear relationship with the failure frequency. The dynamic strain development curve of saturated clay can be simplified to failure, transition, and stability types, which are mainly affected by the cyclic stress ratio. Initial shear stress and vibration frequency have significant effects on the deformation and strength characteristics of saturated clay. The larger the initial shear stress or the lower the vibration frequency is, the more sufficient the dynamic strain of soil develops and the fewer the number of cycles required to reach the same dynamic strain. Under the same number of cycles, the larger the initial shear stress or the lower the vibration frequency, the smaller the dynamic stress required to cause soil failure and the lower the dynamic strength of the soil. A turning point exists in the dynamic strength curve of clay. The smaller the initial shear stress or the higher the vibration frequency, the smoother the curve after the turning point and the smaller the tangent slope.

scholarly journals Experimental Study on the Effects of Initial Shear Stress and Vibration Frequency on Dynamic Strength of Saturated Sands

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Jian Zhang ◽  
Jiuting Cao ◽  
Sijie Huang
Keyword(s):  
Shear Stress ◽  
Internal Friction ◽  
Vibration Frequency ◽  
Stress Ratio ◽  
Dynamic Strength ◽  
Friction Angle ◽  
Cyclic Stress ◽  
Internal Friction Angle ◽  
Shear Stresses ◽  
Cyclic Stress Ratio

The cyclic triaxial system is used to investigate the effects of confining pressure, initial shear stress, cyclic stress ratio, and vibration frequency on the dynamic strength characteristics of saturated sand in the Wenchuan area. Results show that when the vibration frequency is constant, the dynamic strength of sand increases with the increase of the consolidation ratio. However, when the consolidation ratio exceeds a certain value, the dynamic strength of sand decreases or increases slowly. The dynamic internal friction angle first increases and then decreases with the increase of consolidation ratio, and the dynamic internal friction angle under different initial shear stresses differs by a maximum of about 12%. When the failure cycles are constant, the dynamic strength and the dynamic internal friction angle of the sand increase with the increase of vibration frequency, and the dynamic internal friction angle at different frequencies differs by a maximum of about 7%. When the cyclic stress ratio is constant, the higher the vibration frequency, the greater the cycles required to achieve the failure. As the cyclic stress ratio decreases, the influence of the vibration frequency on the failure cycles is gradually reduced.

Effects of Vibration Frequency on Dynamic Properties of Undisturbed Structural Marine Soil

2012 ◽  
Vol 193-194 ◽  
pp. 925-930
Author(s):  
Xiao Ling Chen ◽  
Dong Li ◽  
Rui Min Liu
Keyword(s):  
Pore Pressure ◽  
Vibration Frequency ◽  
Stress Ratio ◽  
Dynamic Strength ◽  
Cyclic Stress ◽  
Triaxial Tests ◽  
Silty Clay ◽  
Threshold Values ◽  
Cyclic Stress Ratio ◽  
Common View

Due to influence by many factors like soil classification, viscosity property and vibration frequency, there is no common view yet about the effect of frequency on dynamic pore pressure and characteristics. In order to study the development of pore pressure, strain and dynamic strength of Hangzhou Bay undisturbed structural silty clay under different vibration frequencies, cyclic triaxial tests were performed. The test results indicate that the frequency has little influence on pore pressure and strain when they didn’t reach the threshold values, but once they exceeded the threshold values the frequency will has strong influence. There is critical cyclic stress ratio when the cyclic stress ratio has not reached that value, the frequency has no influence on dynamic strength. For the given cycles, the higher the frequency is, the bigger the dynamic strength is. And with the increment of frequency, the influence on dynamic is decreased eventually.

Strain degradation of saturated clay under cyclic loading

2001 ◽  
Vol 38 (1) ◽  
pp. 208-212 ◽  
Author(s):  
Jian Zhou ◽  
Xiaonan Gong
Keyword(s):  
Mathematical Model ◽  
Cyclic Loading ◽  
Stress Ratio ◽  
Axial Strain ◽  
Influence Factors ◽  
Cyclic Stress ◽  
Point Of View ◽  
Triaxial Tests ◽  
Cyclic Stress Ratio ◽  
Saturated Clay

Soil degradation is studied from the point of view of cyclic axial strain through stress-controlled triaxial tests on Hangzhou normally consolidated clay. Different influence factors on strain, such as cyclic stress ratio, overconsolidation ratio, and frequency, are studied. Degradation index is redefined according to the tests. A mathematical model for strain degradation is presented and verified.Key words: cyclic loading, saturated clay, strain degradation, mathematical model.

Experimental Study on Dynamic Characteristics of Sandy Pebble Soil

2011 ◽  
Vol 250-253 ◽  
pp. 70-74
Author(s):  
Xiao Qiang Chen ◽  
Bin Jia ◽  
Yong Yao ◽  
Dai Guo Chen
Keyword(s):  
Vibration Frequency ◽  
Dynamic Stress ◽  
Dynamic Strength ◽  
Large Degree ◽  
Confining Pressure ◽  
Dynamic Strain ◽  
Soil Evolution ◽  
Evolution Law ◽  
Dynamic Triaxial Test ◽  
Consolidation Pressure

Through the laboratory dynamic triaxial test of sandy pebble soil, evolution law of influence of confining pressure and vibration frequency on dynamic strength is analyzed. Analysis indicates that dynamic stress of sandy pebble soil improves in a large degree with accretion of vibration frequency, dynamic strength of which increases significantly with confining pressure rising, and relation of dynamic stress and dynamic strain can also be symbolized with the R.L.Kondner hyperbola curve. Meanwhile, dynamic elastic modulus of sandy pebble soil decreases with growth of dynamic strain, while increases with growth of consolidation pressure.

scholarly journals Thermal effects on one-way cyclic behaviour of clay-structure interface

2020 ◽  
Vol 205 ◽  
pp. 05001
Author(s):  
Soheib Maghsoodi ◽  
Olivier Cuisinier ◽  
Farimah Masrouri
Keyword(s):  
Shear Stress ◽  
Stress Ratio ◽  
Cyclic Stress ◽  
Cyclic Stress Ratio ◽  
Direct Shear Tests ◽  
Average Shear Stress ◽  
Average Shear ◽  
Stress Ratios ◽  
Number Of Cycles ◽  
Cycles To Failure

In energy geostructures, which exploit the heat in soil using earth contact elements, the interface is subjected to cyclic thermo-mechanical loads. Monotonic and cyclic constant-volume equivalent-undrained (CVEU) direct shear tests were performed on clay-clay and clay-structure interface at different temperatures (22 and 60 °C). Different cyclic and average stress ratios (CSR and ASR) were applied to the kaolin clay-structure interface under 300 kPa of normal stress. The results showed that, the number of cycles to failure for the clay-structure interface test was lower than that for the clay-clay case in the same range of cyclic and average shear stress ratios. In cyclic clay-structure tests, decreasing the cyclic stress ratio, increased the number of cycles to failure; however, decreasing the average shear stress ratio decreased the number of cycles to failure. Increasing the temperature, decreased the rate of strain accumulation and the number of cycles to failure increased by 2-3 times. The rate of degradation (degradation parameter, t) decreased by 16% with heating from 22 to 60 °C for the different cyclic stress ratios tested.

Study of operating properties of aanticorrosion packing papers

2020 ◽  
Vol 76 (10) ◽  
pp. 1021-1027
Author(s):  
A. P. Ponomarev ◽  
L. G. Kolyada ◽  
E. V. Tarasyuk
Keyword(s):  
Steel Strip ◽  
Low Carbon Steel ◽  
Strength Characteristics ◽  
Low Carbon ◽  
Operating Characteristics ◽  
Packing Materials ◽  
Accelerated Corrosion ◽  
Operating Properties ◽  
Deformation And Strength Characteristics ◽  
Anticorrosion Properties

Metal products are subjected to atmospheric corrosion during transportation and storing. An important way to prevent this negative phenomenon is application of special packing materials, in particular materials, containing volatile inhibitors of corrosion, which protect metal against various corrosion agents. To protect metal effectively it is necessary to provide a definite level of operating characteristics of packing materials. The purpose of the work was the study of operating properties of inhibited crepe, inhibited and laminated polyethylene film, inhibited crepe and reinforced by polypropylene web papers, manufactured by OJSC “PP TechnoKhim”, Magnitogorsk, used for packing of metals. Structural and dimensional, sorption, deformation and strength characteristics, of the studied anticorrosion papers are presented, the characteristics being calculated based on the results of measurements. To determine their physical-mechanical and anticorrosion properties, standard methods and methodologies were used. To evaluate impact of moisture and transportation conditions, indices of water adsorption and wear of the studied papers were determined. Inhibitor content in these materials was determined by thermogravimetric analysis method. Their protective ability was studied on samples of low carbon steel strip. For accelerated corrosion tests the strip samples were degreased by alcohol, dried in air and packed in the studied anticorrosion papers, after that they were exposed under increased temperatures and moisture conditions. It was determined, that among the materials under the study, the inhibited crepe paper, reinforced by polypropylene web, hhas the best complex of physical-mechanical and anticorrosion properties. It provides a higher level of prevention corrosion of metal l and surpasses other materials in a number of deformation and strength characteristics. Recommendations were proposed to improve qquality of produced anticorrosion papers.

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