Evaluation on air-permeability of unsaturated soils subjected to freeze-thaw action

2014 ◽  
pp. 1189-1195
Author(s):  
T Ishikawa ◽  
T Tokoro ◽  
D Nakamura ◽  
S Yamashita
Keyword(s):  
Unsaturated Soils ◽  
Air Permeability ◽  
Freeze Thaw

A flexible wall permeameter for measurements of water and air coefficients of permeability of residual soils

2003 ◽  
Vol 40 (3) ◽  
pp. 559-574 ◽  
Author(s):  
Agus Setianto Samingan ◽  
Eng-Choon Leong ◽  
Harianto Rahardjo
Keyword(s):  
Flow Rate ◽  
Unsaturated Soils ◽  
Temperature Fluctuations ◽  
Air Permeability ◽  
Matric Suction ◽  
Residual Soils ◽  
Volume Changes ◽  
Flexible Wall ◽  
Drying And Wetting Cycles ◽  
Suction Flow

This paper describes the development of a flexible wall permeameter apparatus for measuring the water and air coefficients of permeability of residual soils. Water and air coefficients of permeability were obtained for both the drying and wetting cycles for residual soils using the flexible wall permeameter. Volume changes of the soil specimens during unsaturated consolidation and during the water and air permeability measurements were also monitored. Factors that influence the measurements, such as hydraulic and pneumatic gradients and temperature fluctuations are described and discussed in this paper. The developed flexible wall permeameter was found to be capable of measuring water and air coefficients of permeability as low as 10–12 m/s.Key words: flexible wall permeameter, permeability, residual soils, unsaturated soils, matric suction, flow rate.

scholarly journals Evaluation of frost heave in clay soils

2021 ◽  
Vol 135 (2) ◽  
pp. 14-26
Author(s):  
А. Sarsembayeva ◽  
◽  
A. Zhusshupbekov ◽  
Ph.E.F. Collins ◽  
◽  
...  
Keyword(s):  
Mass Transfer ◽  
Unsaturated Soils ◽  
Soil Samples ◽  
Engineering Properties ◽  
Frost Heave ◽  
Dry Density ◽  
Slight Reduction ◽  
Freeze Thaw ◽  
Coefficient Of Permeability ◽  
Laboratory Test Results

Frost heaving in clayey soils with a low coefficient of permeability raises a lot of questions regarding the cryosuction, surface tension forces, and accompanying phase transfer of water. The freeze-thaw laboratory test results were considered in this work in terms of temperature and volumetric parameters change, dry density, and water mass transfer. The article presents a model for calculating the mass transfer of water (vapour) in the gas state under the influence of cryogenic forces. Findings include the improved understanding of the heat and mass transfer phenomenon during the unidirectional freezing of soils in an open system. Most of the tests for engineering properties registered a slight reduction in relation to strength, cohesion, and angle of internal friction. However, there was a significant increase in the coefficient of permeability after the freeze-thaw cycles with initially dense compacted soil samples, which was due to loosening and moistening of the soil samples during the heave at sub-zero temperatures. The conceptual model for frost heave in soils was developed based on the vapour mass transfer. There was presented algorithm of vapour flow calculation in unsaturated soils using fundamental thermodynamic equations.

Upper subsoil pore characteristics and functions as affected by field traffic and freeze–thaw and dry–wet treatments

Soil Research ◽  
2017 ◽  
Vol 55 (3) ◽  
pp. 234 ◽  
Author(s):  
Per Schjønning ◽  
Mathieu Lamandé ◽  
Valentin Crétin ◽  
Janne Aalborg Nielsen
Keyword(s):  
Soil Layer ◽  
Air Permeability ◽  
Critical Conditions ◽  
Soil Cores ◽  
Soil Functions ◽  
Wheel Load ◽  
Pore Characteristics ◽  
Undisturbed Soil ◽  
Freeze Thaw ◽  
Single Pass

Cultivated soils are subject to very high stresses from machinery. This may affect the soil pore system and its processes, soil functions and soil ecosystem services. Compaction experiments were performed on loamy Luvisols at three sites in Denmark: Aarslev, Flakkebjerg and Taastrup. Non-trafficked control soil was compared with soil subjected to four annual traffic events with approximately 3-, 6- or 8-Mg wheel loads from tractor–trailer combinations. A self-propelled machine with a single pass of approximately 12-Mg wheel load was tested at Aarslev. Undisturbed soil cores were sampled at 0.3m depth when the experimental plots had received either 2 years (Flakkebjerg) or 3 years (Aarslev and Taastrup) of repeated compaction treatment. The volume of air-filled pores and air permeability were quantified for soil drained to –100hPa matric potential. Freeze–thaw and dry–wet treatments were applied to soil cores in the laboratory for Aarslev and Taastrup samples. The multipass machinery significantly affected >30µm soil pores and air permeability at wheel loads of ~6 Mg or higher, whereas no or only minor effects could be detected for ~3-Mg wheel loads. Indices combining air permeabilities with air-filled porosities indicated that pore morphological features had also been affected. Estimates of hydraulic conductivity indicated critical conditions for the percolation of excess rainwater for severely compacted soil at Aarslev. Generally, the single-pass machine with a high wheel load did not affect the pores and their function. A dry–wet event was a more effective remediation of compaction than a freeze–thaw treatment. In conclusion, present-day field traffic risks creating a bottleneck soil layer for important soil functions just below the tilled topsoil.

Soil Response during Globally Drained and Undrained Freeze–Thaw Cycles under Deviatoric Loading

2021 ◽  
Vol 147 (2) ◽  
pp. 06020030
Author(s):  
Sang Yeob Kim ◽  
Junghee Park ◽  
Wonjun Cha ◽  
Jong-Sub Lee ◽  
J. Carlos Santamarina
Keyword(s):  
Soil Response ◽  
Freeze Thaw
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