Automated Triaxial Apparatus for Testing Unsaturated Soils

2006 ◽  
Vol 29 (1) ◽  
pp. 12310 ◽  
Author(s):  
L David Suits ◽  
TC Sheahan ◽  
Z Cabarkapa ◽  
T Cuccovillo
Keyword(s):  
Unsaturated Soils ◽  
Triaxial Apparatus

A new simple system for measuring volume changes in unsaturated soils

2002 ◽  
Vol 39 (3) ◽  
pp. 757-764 ◽  
Author(s):  
C W.W Ng ◽  
L T Zhan ◽  
Y J Cui
Keyword(s):  
Volume Change ◽  
Unsaturated Soils ◽  
Volumetric Strain ◽  
Apparent Volume ◽  
Differential Pressure ◽  
Simple System ◽  
Measuring System ◽  
Volume Changes ◽  
Ambient Temperatures ◽  
Triaxial Apparatus

A new simple system for accurately measuring overall total volume changes in unsaturated soil specimens with a triaxial apparatus is introduced in this paper. The basic principle of the measuring system is to record changes in the differential pressure due to changes in the water level inside an open-ended, bottle-shaped inner cell caused by volume change in the specimen and inside a reference tube using an accurate differential pressure transducer. Several important steps were taken to improve the accuracy and sensitivity of the measuring system. Detailed calibrations were carried out to account for apparent volume changes as a result of changes in cell pressure, fluctuation in the ambient temperatures, creep in the inner cell wall, and relative movement between the loading ram and the inner cell. The calibration results demonstrate that the measuring system is reasonably linear, reversible, and repeatable. The estimated accuracy of the measuring system is in the order of 32 mm3 (or 0.04% volumetric strain for a triaxial specimen 38 mm in diameter and 76 mm in height) once the system is properly calibrated.Key words: unsaturated soils, volume-change measurement, open-ended, bottle-shaped, inner cell, differential pressure, calibration.

A Temperature Controlled Triaxial Apparatus for Testing Unsaturated Soils

2011 ◽  
Vol 34 (5) ◽  
pp. 103586
Author(s):  
L. D. Suits ◽  
T. C. Sheahan ◽  
Anuchit Uchaipichat ◽  
Nasser Khalili ◽  
Saman Zargarbashi
Keyword(s):  
Unsaturated Soils ◽  
Triaxial Apparatus ◽  
Temperature Controlled

Mini suction probe for matric suction measurements

2002 ◽  
Vol 39 (6) ◽  
pp. 1427-1432 ◽  
Author(s):  
Inge Meilani ◽  
Harianto Rahardjo ◽  
Eng-Choon Leong ◽  
Delwyn G Fredlund
Keyword(s):  
Pore Water ◽  
Unsaturated Soils ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Matric Suction ◽  
Lateral Direction ◽  
Triaxial Apparatus ◽  
Specimen Height ◽  
Pressure Changes ◽  
Accurate Reading

A modified triaxial apparatus with mini suction probes was fabricated to study the matric suction along the specimen height during unsaturated triaxial testing. Three mini suction probes were placed at 3/4, 1/2, and 1/4 height of the specimen, each at 120° apart in the lateral direction. This paper presents the development of the mini probe for matric suction measurements. Evaluation of the performance shows that the fabricated mini probe provides a rapid response and accurate reading under negative and positive pore-water pressure changes. Matric suctions as high as 400 kPa were successfully measured on soil specimens over a time span of 15 h. On the other hand, the mini suction probes were also found to be able to measure a matric suction of 200 kPa for a longer period of 155 h.Key words: matric suction, mini suction probe, triaxial, unsaturated soils, mid-height pore-water pressure measurement.

Appareil triaxial pour l'étude du comportement thermique dé sols non saturés

1990 ◽  
Vol 27 (1) ◽  
pp. 119-128 ◽  
Author(s):  
C. Saix ◽  
P. Jouanna
Keyword(s):  
Key Words ◽  
Unsaturated Soils ◽  
Saturated Soils ◽  
Clayey Soils ◽  
Triaxial Apparatus ◽  
State Of Stress ◽  
Thermal Consolidation ◽  
Mechanical Consolidation ◽  
Sols Non Saturés

The thermal consolidation of unsaturated soils in a thermo-hydro-mechanical framework is studied in a thermal triaxial apparatus described in the paper. The results of the first tests performed, under a given state of stress, on both silty and clayey soils, show some similarities between purely thermal consolidation and mechanical consolidation on saturated soils. Key words: unsaturated soils, temperature, triaxial, consolidation. [Journal translation]

Experimental Study on Soil Water Characteristic Curve of Compacted Unsaturated Soil

2010 ◽  
Vol 168-170 ◽  
pp. 1285-1288
Author(s):  
Dong Lin Wang
Keyword(s):  
Soil Water ◽  
Influencing Factors ◽  
Unsaturated Soils ◽  
Stress Condition ◽  
Characteristic Curve ◽  
External Stress ◽  
Method Of Least Squares ◽  
Soil Water Characteristic Curve ◽  
Triaxial Apparatus ◽  
Soil Water Characteristic Curves

Soil water characteristic curve is one of important topics of unsaturated soils. Pressure plate extractor and GDS unsaturated triaxial apparatus are used to study influencing factors including types of soils and net mean stress. Through method of least-squares, Fredlund five-parameter model were employed to fit soil-water characteristic curves. The results show that model provided a satisfactory fit to the experimental data. Through an analysis of influencing factors, we find that not only physical condition of samples but also external stress condition can affect the shape of soil water characteristic curve.

The Experimental Study of Permeability Coefficient of Unsaturated Soil

2011 ◽  
Vol 71-78 ◽  
pp. 1158-1162
Author(s):  
Cui Ran Liu ◽  
Peng Li He ◽  
Huai Feng Tong
Keyword(s):  
Unsaturated Soil ◽  
Permeability Coefficient ◽  
Unsaturated Soils ◽  
Indirect Method ◽  
Direct Method ◽  
Silty Clay ◽  
Test Results ◽  
Triaxial Apparatus ◽  
Technical Requirements ◽  
Direct Measurements

Due to the complexity and variability of unsaturated soil, the permeability property of unsaturated soils is clearly different from that of saturated soil. And because the test equipment is more complex and technical requirements are higher and diachronic cycle is longer, the researches related are slow. Using the triaxial apparatus of unsaturated soil, the direct and indirect experiments to study the permeability coefficient of unsaturated silty clay are done. Test results show that the permeability coefficient of unsaturated soil can be done by the indirect method and direct method. Not only the direct measurements of the permeability coefficient of unsaturated soil are realized through this trial, but also the reliability of indirect method is proved.

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