scholarly journals Geotechnical Properties of Soft Marine Soil at Chan May Port, Vietnam

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Thi Nu NGUYEN ◽  
Thanh Duong NGUYEN ◽  
Truong Son BUI
Keyword(s):  
Shear Strength ◽  
Water Content ◽  
Void Ratio ◽  
Soft Soil ◽  
Field Investigation ◽  
Liquid Limit ◽  
Geotechnical Properties ◽  
Unit Weight ◽  
Dry Unit Weight ◽  
Marine Soil

Soft marine soil deposit is distributed under the sea with many special properties. This type ofsoil is rarely researched in Vietnam because of the difficult geotechnical investigation under the sea level.In this paper, the experimental laboratories were performed to investigate the geotechnical properties ofsoft marine soil at Chan May port, Vietnam. The field investigation results indicate that the thickness ofsoft soil varies from a few meters to more than ten meters. Soft soil has a high value of water content,void ratio, and compressibility and a low value of shear strength. The compression index has a goodrelationship with water content, liquid limit, and dry unit weight. The unit weight, shear strength, and preconsolidationpressure increase with the increase of depth. These results show that the soil in the studyarea is unfavorable for construction activities.

scholarly journals Evaluations of the effects of soil properties and electrical conductivity on the water content reflectometer calibration for landfill cover soils

2017 ◽  
Vol 12 (No. 1) ◽  
pp. 10-17 ◽  
Author(s):  
K. Kim ◽  
J. Sim ◽  
T.-H. Kim
Keyword(s):  
Electrical Conductivity ◽  
Soil Properties ◽  
Water Content ◽  
Clay Content ◽  
Liquid Limit ◽  
Time Domain Reflectometry ◽  
Volumetric Water Content ◽  
Unit Weight ◽  
Landfill Cover ◽  
Dry Unit Weight

This study presents soil-moisture calibrations using low-frequency (15–40 MHz) time domain reflectometry (TDR) probe, referred to as water content reflectometer (WCR), for measuring the volumetric water content of landfill cover soils, developing calibrations for 28 different soils, and evaluating how WCR calibrations are affected by soil properties and electrical conductivity. A 150-mm-diameter PVC cell was used for the initial WCR calibration. Linear and polynomial calibrations were developed for each soil. Although the correlation coefficients (R<sup>2</sup>) for the polynomial calibration are slightly higher, the linear calibrations are accurate and pragmatic to use. The effects of soil electrical conductivity and index properties were investigated using the slopes of linear WCR calibrations. Soils with higher electrical conductivity had lower calibration slopes due to greater attenuation of the signal during transmission in the soil. Soils with higher electrical conductivity tended to have higher clay content, organic matter, liquid limit, and plasticity index. The effects of temperature and dry unit weight on WCR calibrations were assessed in clayey and silty soils. The sensor period was found to increase with the temperature and density increase, with greater sensitivity in fine-textured plastic soils. For typical variations in temperature, errors in volumetric water content on the order of 0.04 can be expected for wet soils and 0.01 for drier soils if temperature corrections are not applied. Errors on the order of 0.03 (clays) and 0.01 (silts) can be expected for typical variations in dry unit weight (± 2 kN/m<sup>3</sup>).

Use of Stiffness for Evaluating Compactness of Cohesive Pavement Geomaterials

2003 ◽  
Vol 1849 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Phillip S. K. Ooi ◽  
Jianping Pu
Keyword(s):  
Shear Strength ◽  
Water Content ◽  
Volume Change ◽  
Degree Of Saturation ◽  
Unit Weight ◽  
Soil Stiffness ◽  
Soil Plasticity ◽  
Dry Unit Weight ◽  
Swell Potential

There has been a recent push toward adoption of in-place soil stiffness as a means of assessing compactness of pavement geomaterials. From a series of low strain GeoGauge stiffness measurements made under controlled laboratory conditions on compacted silts, the variation of stiffness with water content, dry unit weight, degree of saturation, volume change upon wetting, shear strength, and soil plasticity is discussed. In general, the GeoGauge stiffness is not directly related to dry unit weight, and it peaks dry of optimum and decreases upon wetting. Soil specimens with a large stiffness also tend to be stronger, but they also tend to swell more upon wetting, implying that the shrink–swell potential is not optimized if stiffness is. These results help advance the understanding of the role of stiffness in assessing compactness of cohesive geomaterials.

Consolidation Properties of Ho Chi Minh City Soil, Vietnam

2020 ◽  
Vol 54 (1A) ◽  
pp. 1-10
Author(s):  
Vo Nhat Luan
Keyword(s):  
Void Ratio ◽  
Soft Soil ◽  
Liquid Limit ◽  
Ho Chi Minh City ◽  
Compression Index ◽  
Underground Structures ◽  
Compression Pressure ◽  
Coefficient Of Consolidation ◽  
Two Samples ◽  
Index Changes

This paper presents the experimental results of consolidation properties of soft soil in Ho Chi Minh City of Vietnam. Forty-two samples were collected from different locations and were determined in the laboratory by Oedometer test. The results showed that the coefficient of consolidation of soft soil varies from 0.052.10-3 to 3.3.10-3cm2/s, otherwise the compression index changes from 0.156 to 1.703, soil is in a normally consolidated or over the consolidated state. These properties also change differently with depth. It also indicated that the compressive index of soft soil has a fine linear relationship with the liquid limit، water content, and void ratio. The coefficient of consolidation of soft soil decreases with the increase of compression pressure. These parameters are basic for calculating the settlement of underground structures in Ho Chi Minh City.

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 Study on the consolidation properties of soft soil distributed in the North Center coastal area of Vietnam

2020 ◽  
Vol 61 (HTCS6) ◽  
pp. 116-122
Author(s):  
Son Truong Bui ◽  
Nu Thi Nguyen ◽  
Tho Duc Pham ◽  
Duong Thanh Nguyen ◽  
Keyword(s):  
Normal Stress ◽  
Treatment Time ◽  
Soft Soil ◽  
Applied Pressure ◽  
Liquid Limit ◽  
Unit Weight ◽  
Consolidation Pressure ◽  
The North ◽  
Consolidation Coefficient ◽  
Consolidation Parameters

Consolidation parameters of soft soil play an important role in calculating settlement and soft soil improvement by vertical drainage method (distance, quantity, treatment time). In this study, using oedometer tests, consolidation parameters of some soft soils in the North Central coastal region, Vietnam are clarified. The research results show that the compression index Cc has a strong relationship with the natural water content, liquid limit, dry unit weight, and void ratio of the soil. The consolidation coefficient significantly depends on the applied pressure level, at the over-consolidation stage (normal stress is less than pre-consolidation pressure), the consolidation coefficient is high. By contrast, at the normal consolidation stage (normal stress is greater than pre-consolidation pressure), the coefficient of consolidation is small. The pre-consolidation pressure of soil changes with the distribution depth.

scholarly journals STUDI SIFAT MEKANIS TANAH MERAH DENGAN PENGUJIAN TRIAKSIAL

2018 ◽  
Vol 7 (1) ◽  
pp. 29-34
Author(s):  
Redaksi Tim Jurnal
Keyword(s):  
Shear Strength ◽  
Soil Type ◽  
Clay Soil ◽  
Soft Soil ◽  
Soft Clay ◽  
Liquid Limit ◽  
Red Soil ◽  
Triaxial Tests ◽  
Limit Value ◽  
Triaxial Apparatus

Characteristics soft soil can cause instability and long-term degradation problems. This is because the soil has a low shear strength value and high compressibility. One type of soil belonging to the soft soil type is soft clay soil. Red soil belongs to the soft clay soil type. Therefore, the purpose of this research to determines the parameters of the shear strength of red soil in the area of Pakjo City Palembang, South Sumatra Province. The equipment had been used to obtain parameters of mechanical properties of red soil was using Triaxial apparatus. The results of the red soil properties index include: water content value (□ 27.70%, specific gravity value (Gs) 2.67, liquid limit value (LL) 66.00%, value of plastic limit of 25.13% and index value (IP) of 40.87% Classification of soil CH (USCS) and A-7-6 (AASHTO). The result of the Triaxial tests was the value of cohesion (c): 16.25-18, 15 kPa, and internal friction (□): 13.50-14.75⁰. The result of shear strength (□) : 17.68-24.02 kPa. The shear strength value of red soil indicates soil which includes soft soil (12.5-25 kPa).

Effect of Heating Borehole Spacing on Plasticity of Expansive Soil

2020 ◽  
Vol 38 (7A) ◽  
pp. 1062-1068
Author(s):  
Falah H. Rahil ◽  
Husam H. Baqir ◽  
Nabeel J. Tumma
Keyword(s):  
Water Content ◽  
Representative Sample ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Heating System ◽  
Unit Weight ◽  
Initial Water Content ◽  
Initial Water ◽  
Dry Unit Weight ◽  
Laboratory Models

This paper presents the effect of spacing between boreholes heating on plasticity of expansive soils. The expansive soils used were prepared artificially by mixing Kut clay with different percentages of bentonite. Nine laboratory models of expansive soils having dry unit weight of 17.8 kN/m3 with 6% initial water content were prepared inside a steel box of (300 mm × 300 mm × 400 mm height).  A special heating system generates 400 Co for six hours was designed and manufactured for this purpose using 12 mm diameter electric heaters inserted through boreholes. Square pattern boreholes of 170 mm length with spacing (4.16d, 6.25d and 8.33d) were used. A representative sample were taken after heating from the center of the square pattern for measuring the plasticity of the soils. The results showed that the plasticity index remarkedly decreases compared with that before heating and increases with increasing bentonite and the spacing. It is also indicated that an expansive soil could be changed from high to low plasticity

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