Permeability Tests in Rigid-Wall Permeameters: Determining the Degree of Saturation, its Evolution, and its Influence of Test Results

2004 ◽  
Vol 27 (3) ◽  
pp. 10905 ◽  
Author(s):  
L David Suits ◽  
TC Sheahan ◽  
RP Chapuis
Keyword(s):  
Rigid Wall ◽  
Degree Of Saturation ◽  
Test Results

Granular soils in rigid-wall permeameters: method for determining the degree of saturation

1989 ◽  
Vol 26 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Robert P. Chapuis ◽  
Karsten Baass ◽  
Luc Davenne
Keyword(s):  
Hydraulic Conductivity ◽  
Test Procedure ◽  
Rigid Wall ◽  
Standard Test ◽  
Test Method ◽  
Degree Of Saturation ◽  
Granular Soils ◽  
Test Results ◽  
Constant Head

The standard test method used to determine the hydraulic conductivity of a clean granular soil (rigid-wall permeameter –constant head difference) requires that the specimen be saturated with an air-vacuum pump. However, no method is provided to verify whether the sample is fully (100%) saturated. This paper proposes such a method and establishes its accuracy. The method allows for quality control of the rigid-wall permeameter itself: it can detect if it is watertight but not airtight, according to the achieved degree of saturation. A detailed example is given on a proposed data sheet. The reasons for partial saturation and the problems related to air bubbles are examined. The result of this examination is a simplified test to check a permeameter, based on the fact that for unsaturated conditions the hydraulic conductivity depends on which of two ways the water seeps in a given direction. A few modifications in the preparation of the specimen and the test procedure are suggested so as to improve the quality of test results. Key words: permeability, laboratory, granular soils, rigid-wall permeameter, saturation.

Towards a more rational approach to chemical compatibility testing of clay

2002 ◽  
Vol 39 (3) ◽  
pp. 597-607 ◽  
Author(s):  
J K Kodikara ◽  
F Rahman ◽  
S L Barbour
Keyword(s):  
Boundary Condition ◽  
Hydraulic Conductivity ◽  
Rigid Wall ◽  
New Technique ◽  
Rational Approach ◽  
Lateral Strain ◽  
Test Results ◽  
Chemical Compatibility ◽  
Test Technique ◽  
Flexible Wall

Chemical compatibility tests using hydraulic conductivity testing with chemical permeants are normally undertaken to assess the integrity of compacted clayey liners used for waste containment. This paper highlights the fact that current routine methods of flexible wall and rigid wall testing techniques fail to represent the zero lateral strain boundary condition that is required to realistically represent the field situation. The test results indicate that flexible wall permeameters underestimate the likely increases in hydraulic conductivity due to chemicals, while the rigid wall permeameters can severely overestimate these effects. A new test technique, which incorporates the zero lateral strain condition in a simple manner, is presented. This technique involves the use of a rigid wall concept in a flexible wall permeameter. A split rigid mould is used to encase the soil specimen that is glued to the internal surfaces of the mould, to apply the zero lateral strain boundary condition. The new technique is shown to be suitable for both chemical compatibility and desiccation testing. The tests were undertaken with varying concentrations of saline water, methanol, and landfill leachate. The test results indicate that the new technique produces results that fall between the results obtained from flexible wall and rigid wall permeameters. It is argued that the new test technique provides a more rational approach for chemical compatibility testing than the current rigid wall and flexible wall techniques.Key words: soil, hydraulic conductivity, chemical compatibility, landfill, permeameter, boundary condition.

scholarly journals In-situ Desaturation Tests by Electrolysis for Liquefaction Mitigation

2021 ◽  
Author(s):  
Runze Chen ◽  
Yumin Chen ◽  
Hanlong Liu ◽  
Kunxian Zhang ◽  
Ying Zhou ◽  
...  
Keyword(s):  
Minimum Degree ◽  
Electricity Consumption ◽  
Potential Method ◽  
Economic Benefits ◽  
Degree Of Saturation ◽  
Test Results ◽  
Liquefaction Resistance ◽  
The Difference ◽  
Maximum And Minimum Degree

Electrolytic desaturation is a potential method for improving the liquefaction resistance of the liquefiable foundation by reducing the soil saturation. In this study, in-situ desaturation tests were performed to investigate the resistivity of soil at different depth and the water level of the foundation under different current. The test results show that at constant currents of 1 A (Ampere, unit of the direct current), 2 A and 3 A, the saturation of the treated foundation reached 87%, 83% and 80%. During the electrolysis process, the generated gas migrates vertically and horizontally under the influence of buoyancy and gas pressure. In the end of electrolysis, the gas inside the sand foundation basically migrates vertically only. The higher current intensity employed for electrolysis will affect the uniformity and stability of the gas. At constant currents of 1 A, 2 A and 3 A, the difference between the maximum and minimum degree of saturation in the treated foundation was 14%, 18% and 19%; and after electrolysis halted for 144 h, the saturation in the treated foundation was 90%, 85% and 87%. The electricity consumption analysis indicates that the desaturation method has excellent economic benefits in the treatment of saturated sand foundations.

scholarly journals Impact of the moisture content in medium sands on CPTU test results

2016 ◽  
Vol 48 (3) ◽  
pp. 221-231 ◽  
Author(s):  
Łukasz Zawadzki ◽  
Marek Bajda
Keyword(s):  
Moisture Content ◽  
Unsaturated Soils ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Degree Of Saturation ◽  
Test Results ◽  
Time Dynamic ◽  
Tip Resistance ◽  
The Impact ◽  
Resistance Value

Abstract Soils occurring in the soil “active zone” are in contact with the surface and are directly influenced by external factors (mainly climatic changes) that cause variation in their parameters over time. Dynamic and uncontrolled changes of soil properties e.g. due to rainfall and evapotranspiration processes may affect field test results leading to the misinterpretation of the obtained data. This paper presents investigations on the influence of moisture content changes in sandy soils on CPTU results. For this purpose, a field ground model has been constructed and five CPTU tests with a different moisture content of soil were carried out. During the investigations, the tip resistance (qc), friction on sleeve (fs), and pore water pressure (u2) were measured. Moreover, a TDR probe was applied to determine the distribution of the moisture content in the studied soil columns. Differences between CPT results obtained in saturated and unsaturated soils have been shown. Furthermore, a simple equation to correct the tip resistance value due to the impact of the degree of saturation has been proposed.

Experimental Study on Test Methods of the Intergranular Suction of Unsaturated Lateritic Soil

2013 ◽  
Vol 353-356 ◽  
pp. 440-445
Author(s):  
Hua Lu ◽  
Yang Wang ◽  
Xiao Yan Wang ◽  
Li Jun Hou ◽  
Xin Zhao Jiang
Keyword(s):  
Southern China ◽  
Quantitative Relationship ◽  
Test Methods ◽  
Degree Of Saturation ◽  
Lateritic Soil ◽  
Test Results ◽  
Empirical Parameter ◽  
Pore Fluid Chemistry ◽  
Unsaturated Condition ◽  
The Relationship

This paper aims at the test methods of the suction between grains of lateritic soil which is widely distributed in southern China, and proposes the test methods and principles according to the variation of the suctions various components. This paper works over the relationship between the suction and the degree of saturation through tests, and also analyzes pore fluid chemistry influence on the suction between grains. The test results show that the test principles and methods are feasible. They also show that the quantitative relationship between the unsaturated soil’s shear strength and saturation (water content), and a new understanding of the physical meaning in unsaturated condition of X, which is a empirical parameter in the principle of Bishop‘s effective stress.

Variation of Initial Soil Suction with Compaction Conditions for Clayey Soils

2012 ◽  
Vol 28 (3) ◽  
pp. 431-437 ◽  
Author(s):  
S.-R. Yang ◽  
H.-D. Lin ◽  
W.-H. Huang
Keyword(s):  
Water Content ◽  
Clay Fraction ◽  
Degree Of Saturation ◽  
Soil Suction ◽  
Clayey Soils ◽  
Test Results ◽  
Wide Range ◽  
Initial Soil ◽  
Compaction Energy ◽  
The Relationship

AbstractIn this study, the initial soil suction of as-compacted clayey soils was evaluated for various compaction conditions, covering a wide range of compaction energy and molding water content. The soil specimens were prepared by impact compaction under three levels of compaction energy. The filter paper method was used to measure the initial soil suction of as-compacted specimens. Test results indicate that the relationship between the soil suction and the molding water content is bilinear under three different compaction energies. However, the effect of compaction energy on soil suction is different for the soils with different amounts of clay fraction and is elucidated by the macro soil properties. The change of soil suction due to different compaction energies can be predicted by the void ratio and the degree of saturation.

Hydraulic fracture in earth and rock-fill dams

1990 ◽  
Vol 27 (4) ◽  
pp. 496-506 ◽  
Author(s):  
K. Y. Lo ◽  
Kiny Kaniaru
Keyword(s):  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Laboratory Tests ◽  
Field Performance ◽  
Degree Of Saturation ◽  
Theoretical Expression ◽  
Test Results ◽  
Rock Fill ◽  
Fracture Pressure ◽  
Theoretical Predictions

Unsatisfactory performance of earth and rock-fill dams involving excessive seepage, piping or failure has been attributed to hydrofracture of the core. Although the phenomenon has been reported for some time, important factors influencing hydraulic fracturing pressure, such as saturation and consolidation, have received relatively little attention; nor have results of laboratory tests or theoretical study been directly related to field performance. In this paper, laboratory hydrofracturing tests under well-defined conditions were performed. A simple theoretical expression for fracture pressure is developed involving only conventional soil strength parameters. Case histories involving hydraulic fracturing of the earthcore are reviewed, and "field" hydraulic fracture pressure and crack closure pressure are defined. The results of the laboratory tests show that hydraulic fracture pressure is not a unique soil property; its value depends on the degree of saturation and consolidation. A comparison of the data deduced from case records with test results and theoretical predictions indicates general consistency. The field hydraulic fracturing pressures are bounded in the upper limit by results from saturated-consolidated tests and in the lower limit by results of saturated–unconsolidated hydraulic fracturing tests. It is suggested that the methodology presented may be useful in the assessment of risk of hydraulic fracturing of dams. Key words: earth and rock-fill dams, hydraulic fracture, tensile strength, seepage, Teton Dam.

scholarly journals Evaluation by different methodologies of collapse potential of some residual soils in Aburrá and San Nicolás Valleys

2015 ◽  
pp. 60-64
Author(s):  
Yamile Valencia González ◽  
Jorge Andrés Yepes-García ◽  
Oscar Echeverri-Ramírez
Keyword(s):  
Material Properties ◽  
Reliability Evaluation ◽  
Degree Of Saturation ◽  
Test Results ◽  
Residual Soils ◽  
Collapse Potential ◽  
Oedometer Test ◽  
Traditional Test ◽  
Soil Volume

The process of precipitated variation of a soil volume when subjected to increase in stresses which withstand and/or the degree of saturation, it's also known as collapse. Collapse Potential of soils can be determined from correlations derivative of the material properties index. That's why in this work, it was evaluated using different methods the Collapse Potential of soils for ten specimens of tropical residual soils coming from five different points in Aburrá and San Nicolás Valleys, and the results were compared with the index collapse obtained using the duple-oedometer test. It was achieved to establish which of the procedures is closer to the traditional test results, and thereby obtain an approximation to the potential collapse using easy implementation methodologies with significant costs savings and rehearsal times, without loss of reliability evaluation.

Water content - void ratio swell-shrink paths of compacted expansive soils

2002 ◽  
Vol 39 (4) ◽  
pp. 938-959 ◽  
Author(s):  
S Tripathy ◽  
KS Subba Rao ◽  
D G Fredlund
Keyword(s):  
Water Content ◽  
Void Ratio ◽  
Expansive Soils ◽  
Degree Of Saturation ◽  
Test Results ◽  
Volumetric Change ◽  
Linear Portion ◽  
Ratio Change ◽  
Oedometer Tests ◽  
Vertical Deformations

This paper addresses the behaviour of compacted expansive soils under swell–shrink cycles. Laboratory cyclic swell–shrink tests were conducted on compacted specimens of two expansive soils at surcharge pressures of 6.25, 50.00, and 100.00 kPa. The void ratio and water content of the specimens at several intermediate stages during swelling until the end of swelling and during shrinkage until the end of shrinkage were determined to trace the water content versus void ratio paths with an increasing number of swell–shrink cycles. The test results showed that the swell–shrink path was reversible once the soil reached an equilibrium stage where the vertical deformations during swelling and shrinkage were the same. This usually occurred after about four swell–shrink cycles. The swelling and shrinkage path of each specimen subjected to full swelling – full shrinkage cycles showed an S-shaped curve (two curvilinear portions and a linear portion). However, the swelling and shrinkage path occurred as a part of the S-shaped curve, when the specimen was subjected to full swelling – partial shrinkage cycles. More than 80% of the total volumetric change and more than 50% of the total vertical deformation occurred in the central linear portion of the S-shaped curve. The volumetric change was essentially parallel to the saturation line within a degree of saturation range of 50–80% for the equilibrium cycle. The primary value of the swell–shrink path is to provide information regarding the void ratio change that would occur for a given change in water content for any possible swell–shrink pattern. It is suggested that these swell–shrink paths can be established with a limited number of tests in the laboratory.Key words: expansive soils, oedometer tests, swell–shrink behaviour, shrinkage tests.

Sign in / Sign up

Export Citation Format

Share Document