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.

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.

Improvement of Barrier Soil Properties with Fly Ash to Minimize Desiccation Shrinkage

2012 ◽  
Vol 7 ◽  
pp. 1-11 ◽  
Author(s):  
Agapitus A. Amadi
Keyword(s):  
Fly Ash ◽  
Hydraulic Conductivity ◽  
Water Content ◽  
Dry Weight ◽  
Shrinkage Strain ◽  
Volumetric Shrinkage ◽  
Unit Weight ◽  
British Standard ◽  
Fine Grained ◽  
Dry Unit Weight

Barrier Systems Built with Fine Grained Soils Frequently Loose their Hydraulic Integrity due to Desiccation Cracking either during Construction or Shortly Thereafter. Moreover, Typical Specifications for the Construction of Compacted Soil Liners and Covers Require that the Soil Be Compacted Wet of Optimum Water Contents to Achieve the Lowest Possible Hydraulic Conductivity, a Condition that Results in High Desiccation Shrinkage Values. however, such Soils Can Be Treated with Fly Ash to Maintain Low and Tolerable Desiccation Shrinkage Strains. in this Study, Volumetric Shrinkage Strains of Representative Fine Grained Soil Containing 0 – 20% Fly Ash by Dry Weight of Soil Compacted with the British Standard Light (BSL), West African Standard (WAS) and British Standard Heavy, (BSH) Compaction Efforts at Moisture Contents Ranging from 10 – 20% Were Evaluated. Measurements Indicate that Volumetric Shrinkage Strain Decreased with Higher Fly Ash Content and that Fly Ash Effectively Reduced the Shrinkage of Untreated Soil Prepared Wet of Optimum from 4.4 – 7.7% to Values Well below the 4% Threshold. the Measured Shrinkage Strains Were Related to Water Content and Dry Unit Weight on the Dry Unit Weight – Moulding Water Content Curve in what Is Referred to as Acceptable Zone. Data Points within the Acceptable Zone Represent Test Results with Shrinkage Strain ≤ 4% which Ensures Compaction Efficiency. this Study Therefore Established that Fly Ash Application and Appropriate Regulation of the Moulding Water Content Are Feasible Means of Reducing the Risk of Barrier Soil Damage by Shrinkage Cracks while still Realizing Very Low Hydraulic Conductivity and Adequate Strength.

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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