Creep behavior of fine-grained frozen soils

1991 ◽  
Vol 28 (4) ◽  
pp. 489-502 ◽  
Author(s):  
H. Wijeweera ◽  
R. C. Joshi
Keyword(s):  
Water Content ◽  
Creep Behavior ◽  
Creep Model ◽  
Secondary Creep ◽  
Total Water Content ◽  
Total Water ◽  
Creep Tests ◽  
Frozen Soils ◽  
Fine Grained ◽  
Creep Stress

Uniaxial compressive creep tests were conducted on saturated samples of six fine-grained frozen soils. The creep behavior of the soils with respect to variation in the creep stress, temperature, and total water content is examined. The test results indicate existence of a unique relationship between the secondary creep rate, [Formula: see text], and the time to the onset of the secondary creep stage, ts, which is dependent only on the soil type. The values [Formula: see text], ts, and the initial strain rate are found to be directly related to the relative creep load (creep stress to peak strength ratio) acting on the soil. Results indicate these relationships to be independent of temperature. A method of analysis is presented whereby the creep behavior of a fine-grained frozen soil at various stresses, temperatures, and total water contents can be predicted, using data from a few creep tests conducted at only one reference temperature and total water content. A secondary creep model is introduced that predicts the creep behavior reasonably well in fine-grained frozen soils. The results obtained from this study are of importance to practicing engineers. Key words: fine grained, frozen soils, creep, load, temperature, water content, compressive strength, creep model.

Compressive strength behavior of fine-grained frozen soils

1990 ◽  
Vol 27 (4) ◽  
pp. 472-483 ◽  
Author(s):  
Harsha Wijeweera ◽  
Ramesh C. Joshi
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Yield Stress ◽  
Constant Strain Rate ◽  
Unit Weight ◽  
Total Water Content ◽  
Total Water ◽  
Frozen Soils ◽  
Fine Grained ◽  
Dry Unit Weight

Constant strain-rate (0.01/s) uniaxial compression-strength tests were conducted on more than 200 saturated samples of six fine-grained frozen soils at temperatures between −5 and −17 °C. Saturated soil samples containing total water contents between 15% and 105% were prepared using a consolidation apparatus specially designed for this purpose. The effect of dry unit weight, total water content, temperature, and soil type on the behavior of peak compressive strength was studied. Test results indicate the peak compressive strength of fine-grained soils is sensitive to changes in the dry unit weight and the total water content. The temperature dependence of the peak compressive strength is represented by a simple power law. An empirical formula has been developed to predict the peak compressive strength of fine-grained frozen soils at a particular temperature using index properties, specific surface area, particle-size distribution, and dry unit weight. A linear relationship exists between the peak compressive stress and the yield stress. Key words: peak compressive strength, yield stress, frozen soils, fine-grained soils, dry unit weight, failure strain, temperature, total water content, slurry consolidation.

scholarly journals Creep Strain Analysis and an Improved Creep Model of Granite Based on the Ratio of Deviatoric Stress-Peak Strength under Different Confining Pressures

2021 ◽  
Author(s):  
Li Qian ◽  
Jianhai Zhang ◽  
Xianliang Wang ◽  
Yonghong Li ◽  
Ru Zhang ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Creep Behavior ◽  
Viscosity Coefficient ◽  
Deviatoric Stress ◽  
Peak Strength ◽  
Creep Model ◽  
Secondary Creep ◽  
Creep Tests ◽  
Underground Powerhouse ◽  
Confining Pressures

Abstract Creep refers to the deformation of rock with time under long-term applied stress, which occur in most underground engineering. The creep behavior of granite in Shuang jiangkou underground powerhouse in Western Sichuan Province, China, was studied by creep tests. Based on test results, a new parameter DPR, the ratio of deviatoric stress to peak strength, is proposed. DPR is found to be a key parameter to describe creep parameters such as instantaneous elastic modulus, creep elastic modulus, and viscosity coefficient of rock under different confining pressures. Creep tests show that instantaneous elastic modulus increases with the increase of DPR. Creep elastic modulus increases when DPR changes from 0.54 to 0.7004, but decreases when DPR is from 0.7004 to 0.88, indicating fractures in rock closes firstly and then new fractures are generated. The viscosity coefficient of the rock increases first and then decreases with the increase of DPR, and when DPR = 0.7171, viscosity coefficient is maximum, indicating the time for rock to reach stability is the longest in creep tests. By introducing DPR and confining pressure into creep model, which interconnect creep parameters in a unified expression, an improved generalized Kelvin creep model is proposed which can accurately describe the primary and the secondary creep behavior of granite under given deviatoric stresses and confining pressures.

An Experimental Study on the Effect of Prior Plastic Straining on Creep Behavior of 304 Stainless Steel

1993 ◽  
Vol 115 (2) ◽  
pp. 200-203 ◽  
Author(s):  
Z. Xia ◽  
F. Ellyin
Keyword(s):  
Stainless Steel ◽  
Plastic Strain ◽  
Strain Rate ◽  
Creep Behavior ◽  
Test Procedure ◽  
Constant Strain Rate ◽  
304 Stainless Steel ◽  
Creep Model ◽  
Plastic Strain Rate ◽  
Creep Tests

Constant strain-rate plastic straining followed by creep tests were conducted to investigate the effect of prior plastic straining on the subsequent creep behavior of 304 stainless steel at room temperature. The effects of plastic strain and plastic strain-rate were delineated by a specially designed test procedure, and it is found that both factors have a strong influence on the subsequent creep deformation. A creep model combining the two factors is then developed. The predictions of the model are in good agreement with the test results.

scholarly journals Indicators of the water regime of some varieties of chrysanthemums in the conditions of the South Ural

2021 ◽  
Vol 10 (1) ◽  
pp. 57-64
Author(s):  
Svetlana Galimullovna Denisova ◽  
Antonina Anatolyevna Reut
Keyword(s):  
Water Content ◽  
Water Deficit ◽  
Water Regime ◽  
Water Holding Capacity ◽  
Research Centre ◽  
Total Water Content ◽  
Total Water ◽  
The South ◽  
Irreversible Damage ◽  
Water Holding

In introduction studies, it is of great importance to determine how favorable the water balance of the studied species is under given environmental conditions. The aim of the research was to study the water regime of some varieties of chrysanthemums in the conditions of the Southern Ural. The study was conducted in 20182020 on the basis of the South-Ural Botanical Garden-Institute of the Ufa Federal Research Centre of Russian Academy of Sciences. The objects of the study were 23 varieties of Chrysanthemum hortorum Bailey. In the course of the research, the total water content, water-holding capacity, the content of mobile moisture, water deficit, and sublethal water deficit were determined. The analysis of water regime indicators is based on the method of artificial wilting (V.N. Tarenkov, L.N. Ivanova) and the method of saturation of plant samples (V.P. Moiseev, N.P. Reshetsky). Sublethal water deficit was determined by the method of T.K. Goryshina, L.I. Samsonova, modified by N.I. Bobrovskaya. The calculations were carried out by standard methods using statistical packages of the Microsoft Excel 2003 and the Agros 2.13 program. The studies made it possible to determine the value of the sublethal water deficit (28,4%) for the varieties of chrysanthemums in the conditions of the Bashkir Ural. It was found that the studied varieties during the growing season did not experience such a moisture deficit in the tissues that could lead to irreversible damage to the assimilating organs. Our experiments showed that chrysanthemum varieties in the Bashkir Cis-Ural under the same soil-climatic and agrotechnical conditions had the following range of indicators of total water content 70,090,4% and water-holding capacity 19,0064,6%. The analysis of variance revealed significant differences between water-holding capacity and the content of mobile moisture by varieties, the share of influence was 27,8531,71%. As a result of the correlation-regression analysis, the authors revealed a direct dependence of the indicators of mobile moisture content on the total water content, and an inverse one on the indicators of the content of mobile moisture and water-holding capacity.

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