A Diffused Air Volume Indicator for Unsaturated Soils

1975 ◽  
Vol 12 (4) ◽  
pp. 533-539 ◽  
Author(s):  
D. G. Fredlund
Keyword(s):  
Correction Factor ◽  
Volume Change ◽  
Unsaturated Soils ◽  
Effective Means ◽  
Computational Procedure ◽  
Technical Note ◽  
Water Volume ◽  
Volume Weight ◽  
Air Volume ◽  
Change Characteristics

The diffusion of air through saturated high air entry discs presents a serious problem in the testing of unsaturated soils. When determining either the strength (drained) or volume change characteristics of unsaturated soils, a technique must be available to measure the amount of diffused air in order for the appropriate corrections to be applied to the volume–weight relationships.The described diffused air volume indicator is a simple but effective means of measuring the quantity of diffused air. This technical note explains its construction and procedure of operation. Also outlined is the computational procedure for the correction factor that must be applied to the water volume change measurements. Numerous tests on the indicator show a reliability in the order of ±0.2 cc over a period of 2.5 weeks.

Constitutive relations for volume change in unsaturated soils

1976 ◽  
Vol 13 (3) ◽  
pp. 261-276 ◽  
Author(s):  
D. G. Fredlund ◽  
N. R. Morgenstern
Keyword(s):  
Volume Change ◽  
Unsaturated Soils ◽  
Soil Structure ◽  
Constitutive Relations ◽  
Water Volume ◽  
Engineering Practice ◽  
State Variables ◽  
Volume Changes ◽  
Stress Changes ◽  
Measured Volume

Volume change constitutive relations for unsaturated soils are proposed from a semi-empirical standpoint. One equation describes the deformation of the soil structure and a second equation defines the volume of water present in the element. Each equation can be viewed as a three-dimensional surface with two independent stress state variables forming the abscissas.Uniqueness is tested by measuring volume changes resulting from stress changes in two orthogonal directions and comparing predicted and measured volume changes resulting from a stress change in a third direction. Samples of undisturbed Regina Clay and compacted kaolin showed good agreement between the predicted and measured volume changes for monotonic deformation of the soil structure. The agreement was not as close for the water phase. The variation was attributed to difficulties in measuring water volume changes over a long period of time. The laboratory results indicate that the proposed constitutive equations are of the appropriate form for use in engineering practice.

Pore-water pressure and water volume change of an unsaturated soil under infiltration conditions

2005 ◽  
Vol 42 (6) ◽  
pp. 1509-1531 ◽  
Author(s):  
Inge Meilani ◽  
Harianto Rahardjo ◽  
Eng-Choon Leong
Keyword(s):  
Pore Water ◽  
Volume Change ◽  
Unsaturated Soils ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Volumetric Strain ◽  
Confining Pressure ◽  
Matric Suction ◽  
Water Volume ◽  
Infiltration Tests

Triaxial shearing–infiltration tests were conducted to study the pore-water pressure and volume change of unsaturated soils subjected to infiltration conditions. A modified triaxial apparatus with three Nanyang Technological University (NTU) mini suction probes along the specimen height was used for the experimental program. Elastic moduli were obtained for the soil structure with respect to changes in net confining pressure (E) and matric suction (H). Water volumetric moduli associated with changes in net confining pressure (Ew) and matric suction (Hw) were also obtained from the shearing–infiltration tests. Water volumetric strain and pore-water pressure during the shearing–infiltration tests were computed based on volume change theory. This paper presents the significance of obtaining the parameter Hw from an appropriate scanning curve of a soil-water characteristic curve (SWCC) for the computation of water volumetric strain and pore-water pressure changes during a shearing–infiltration test. The appropriate scanning curve should be obtained from the wetting curve of the SWCC at the matric suction where the infiltration test commences.Key words: infiltration, matric suction, triaxial, unsaturated soils, pore-water pressure, water volume change.

Stress-Strain and Volume Change Characteristics of an Assemblage of Polymer Pellets

1998 ◽  
Vol 13 (4) ◽  
pp. 347-357 ◽  
Author(s):  
D. Penumadu ◽  
J. A. Yamamuro ◽  
A. E. Abrantes ◽  
G. A. Campbell
Keyword(s):  
Volume Change ◽  
Stress Strain ◽  
Change Characteristics

scholarly journals The Analysis for Energy Consumption of Marine Air Conditioning System Based on VAV and VWV

2018 ◽  
Vol 38 ◽  
pp. 04012
Author(s):  
Sai Feng Xu ◽  
Xing Lin Yang ◽  
Zou Ying Le
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Air Conditioning ◽  
Water Volume ◽  
Pump System ◽  
Air Conditioning System ◽  
Variable Air Volume ◽  
Air Volume ◽  
Marine Air ◽  
Variable Water

For ocean-going vessels sailing in different areas on the sea, the change of external environment factors will cause frequent changes in load, traditional ship air-conditioning system is usually designed with a fixed cooling capacity, this design method causes serious waste of resources. A new type of sea-based air conditioning system is proposed in this paper, which uses the sea-based source heat pump system, combined with variable air volume, variable water technology. The multifunctional cabins’ dynamic loads for a ship navigating in a typical Eurasian route were calculated based on Simulink. The model can predict changes in full voyage load. Based on the simulation model, the effects of variable air volume and variable water volume on the energy consumption of the air-conditioning system are analyzed. The results show that: When the VAV is coupled with the VWV, the energy saving rate is 23.2%. Therefore, the application of variable air volume and variable water technology to marine air conditioning systems can achieve economical and energy saving advantages.

A novel non-contacting laser displacement transducer technique for volume change measurements of unsaturated soils

2010 ◽  
pp. 751-756 ◽  
Author(s):  
X Zhang ◽  
M Mavroulidou ◽  
M Gunn ◽  
Z Cabarkapa ◽  
J Sutton
Keyword(s):  
Volume Change ◽  
Unsaturated Soils ◽  
Displacement Transducer
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