bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laboratory Pull-Out Testing of Grid Reinforcements in Sand
Authors: Ingold TS 
Published: February 2009

Abstract
In many reinforced soil applications the critical mode of failure involves pull-out of the reinforcement from the soil. Although grid reinforcement is known to be very efficient in resisting pull-out failure, very little is published on the mechanisms of soil-grid interaction. To investigate soil-grid behavior, several series of pull-out tests were conducted using both metallic and plastic grids embedded in sand. The results of these tests are presented in this paper together with details of the apparatus and testing techniques used. Results are also given for ancillary testing carried out to assess the effects of grid member orientation with respect to the direction of the applied pull-out load. These tests clearly demonstrate that pull-out resistance is a function of the cumulative embedded area of the grid members normal to the direction of pull-out and not the embedded plan area of the reinforcement. Based on these observations an analytical model is developed for strong inextensible grids. Analytical and test results are compared and found to be in good agreement for both metallic and plastic grids.
Dynamic Shear Modulus and Damping Ratio from Random Loading Tests
Authors: Al-Sanad H , Aggour MS , Yang JCS 
Published: February 2009

Abstract
Dynamic shear modulus and damping ratio determination from random loading tests on dry Monterey and Ottawa sands in a resonant column device, in addition to sinusoidal loading, are presented. In the random excitation test, white noise was used to excite the specimens, and the responses of the specimens were analyzed by the random decrement technique. Using a sine-wave generator, the dynamic soil properties were also determined by the conventional technique. The results obtained indicated a good agreement between the modulus and damping obtained from the application of sinusoidal or random loading. It was concluded that the relationship of shear modulus and damping ratio with shear strain amplitude is independent of random or sinusoidal forcing functions within the range of variables tested.
The Methylene Blue Test for Bentonite Liner Quality Control
Authors: Alther GR 
Published: February 2009

Abstract
An in-situ procedure for evaluating the quality of soil and soil/bentonite admix liners is described. The methylene blue (MB) test is based on the principle that cationic dyes base exchange in proportion to the clay content in soils or clay slurries. The number of exchangeable ions present is determined by replacing these ions with methylene blue.
The MB test is the accepted standard of measurement of clay levels in bentonite bonded molding sands used in the foundry and steel industries. Lab tests have shown that the methylene blue method is useful to test the quality of bentonite liners, bentonite slurries, and soil bentonite backfills for slurry trenches.
Improved Rectangular Hyperbola Method for the Determination of Coefficient of Consolidation
Authors: Sridharan A , Prakash K 
Published: February 2009

Abstract
From the Terzaghi's theory of consolidation, it can be shown that the T/U versus T relation is a rectangular hyperbola over a fairly wide range of degree of consolidation. In the plot of T/U versus T, a straight line is fitted for the range of 60 to 90% degree of consolidation with a high precision. A method of calculating the coefficient of consolidation Cv is presented. The results are compared with the results obtained by the conventional methods, viz, square root of time fitting method and logarithm of time fitting method.
Interpretation of Lateral Statnamic Load Test Results
Authors: El Naggar MH 
Published: February 2009

Abstract
The Statnamic device has been used to test piles in the lateral direction. This paper describes a dynamic analysis approach for the prediction of the static lateral behavior of piles using the results of the Statnamic lateral test. The objectives of this analysis are twofold: to simulate the pile head displacement-time history observed during the test using the measured load time history at the pile head and varying the soil parameters along the pile shaft until a satisfactory match is achieved and to predict the static lateral load-deflection curve of the pile using the soil parameters established through the matching process. The dynamic analysis was used to analyze some Statnamic lateral tests, and satisfactory agreement between the computed and measured displacement-time histories was achieved. The predictions of the proposed approach in the given case studies were in good agreement with the static lateral load test results. The results obtained thus far suggest that the Statnamic lateral test and the described model are successful in the prediction of the lateral load-deflection behavior of piles. Both the Statnamic lateral test and the one-dimensional analysis are simple, fast, and inexpensive, and the approach promises to be very useful in the prediction of the lateral load-deflection behavior of foundations.
Evaluation of Surface-Related Phenomena Using Sedimentation Tests
Authors: Fam M , Dusseault M 
Published: February 2009

Abstract
Sedimentation tests are suggested to assess the sensitivity of clay-water systems to environmental changes. A simple framework based on a parallel structure assumption was developed to analyze data from sedimentation tests. The slope of the relationship between the final sediment volume and the ionic concentration, plotted on a log-log scale, is related to the specific surface Sa, the double layer thickness ϑ, and to the specific gravity Gs. A new parameter, λ, the reactivity coefficient, where λ = Sa · ϑ · Gs · ρw, is introduced to help identification of reactive clay-water systems. High values of λ identify systems that are sensitive to changes in pore fluid characteristics. An experimental procedure is suggested to acquire relevant sedimentation parameters. Data collected during sedimentation tests of kaolinite, bentonite, and disaggregated Pierre shale, Mancos shale, and Queenston shale are used to verify the model. Agreement between experimental data and the model suggests that this simple technique can be used to identify reactive shales in the field. Other applications arise in tailing pond modeling, drilling mud management, and clay liner reliability assessment.
Consolidation and Permeability Behavior of High Porosity Baltic Seabed Sediments
Authors: Ag A , Silva AJ 
Published: February 2009

AbstractThe consolidation and permeability (hydraulic conductivity) characteristics of the high-porosity surficial seabed sediments from a test site in the Eckernförde Bay, Baltic Sea, were studied using a constant rate of strain (CRS) consolidation and hydraulic conductivity testing system employing flow pumps. These silty clay sediments are characterized by high void ratios, high organic content, and variable concentration of methane gas. Results from CRS consolidation tests show appreciable apparent overconsolidation of the sediments at the upper 200 cm with a gradual transition to normally consolidated states below 250 cm in depth. The highly compressible nature of the material is reflected in the large values of the compression index. The hydraulic conductivity of the box core samples ranges from 2.5 × 10−7 to 3.0 × 10−6 cm/s for void ratios ranging from 4.5 to 7.0 with a linear relationship between void ratio and log of hydraulic conductivity. The engineering behavior of these sediments is of practical significance in geoacoustic modeling of the seafloor for studies related to mine countermeasure programs.
Model Tests for Uplift Resistance of Piles in Sand
Authors: Al-Mhaidib AI , Edil TB 
Published: February 2009

Abstract
An experimental program using large model piles in sand was conducted to study the shaft resistance behavior of piles subject to uplift loads. Model single pipe piles of different diameters (45 to 178 mm) were subjected to static uplift loading to failure. The piles, which had an embedded length of about 1.7 to 2 m, were installed in a large test pit (3 by 3 by 3 m) by three different methods (driving, jacking, and a reference undisturbed method with negligible lateral displacement) to assess the influence of method of installation on shaft resistance. The tests were performed in two initial densities of a sand (loose and dense). The experimental results were analyzed statistically. The results show that the initial sand density and the method of pile installation are the most significant factors that affect uplift capacity. Installation methods that cause less disturbance give higher uplift capacity. Unit shaft resistance could be reduced as much as by half depending on the method of pile installation relative to the undisturbed method. The displacement at the ultimate uplift load is in the range of 5 to 12.5 mm and independent of soil type and pile diameter, but depends on method of pile installation.
Mechanism Controlling the Shrinkage Limit of Soils
Authors: Sridharan A , Prakash K 
Published: February 2009

Abstract
Based on the results from an extensive experimental program involving a number of natural soils as well as pure clays with extreme clay mineral types, namely kaolinite and montmorillonite, as the principal clay minerals, a hypothesis explaining the mechanisms controlling the shrinkage limit has been proposed. The shrinkage limit of a natural soil has been shown to be primarily a result of the packing phenomenon, which in turn is governed by the grain-size distribution of the soil; the shrinkage limit of pure clays appears to be affected by the fabric also. Even though clay-sized particles play an important role in the shrinkage phenomenon, there is an optimum clay content at which the shrinkage limit of a soil can become minimum. It has been further illustrated that the shrinkage limit is not at all related to the plasticity characteristics of the soil. As the factors governing the shrinkage limit are entirely different from those controlling the swelling of soils, the shrinkage limit cannot indicate the swelling behavior of the soil.
The In-Plane Permeability of Geotextiles
Authors: Gerry BS , Raymond GP 
Published: February 2009

Abstract
Since about 1965, synthetic fabrics commonly known as geotextiles have contributed to the solution of many civil engineering drainage, separation, and reinforcement problems. In recent years an effort has been made to develop general guidelines for the selection of geotextiles for various specific uses. One of these uses of geotextiles is in railroad track rehabilitation. A primary function of a geotextile for use in track rehabilitation is to facilitate the lateral drainage of excess water from the track load-bearing area to the drainage ditches. As the ballast above the geotextile becomes fouled, the importance of the in-plane drainage capability of the geotextile becomes more and more important. Accordingly, the work presented herein addresses the measurement of the in-plane permeability of geotextiles. Laboratory tests conducted over normal loads likely to be incurred in the track suggest that only thick nonwoven geotextiles are likely to possess coefficients of inplane permeability sufficient to maintain a satisfactory long-term performance. Geotextile specimens removed from beneath ballast substantiate this finding. Furthermore, tests performed on the geotextiles removed from in-track strongly suggest that better performance is obtained from those thick nonwoven geotextiles with low equivalent opening sizes (EOS). From the data it is recommended that in order to meet the in-plane permeability requirement, geotextiles for track rehabilitation be thick nonwoven geotextiles with an EOS preferably less than 40-µm (No. 400) sieve.
Infiltration Testing for Hydraulic Conductivity of Soil Liners
Authors: Stewart JP , Nolan TW 
Published: February 2009

Abstract
This paper describes the use of single ring infiltrometers for evaluating the hydraulic conductivity of compacted soil liners. Procedures are presented for installation and monitoring of infiltrometers in the field. Results of hydraulic conductivity estimated from infiltrometer tests on six laboratory model liners are presented and compared with the results of conventional laboratory tests. In addition, the distribution of soil saturation after prolonged infiltration testing showed that the permeant tended to follow preferred paths and did not generally advance as a uniform front as commonly assumed.
Modified Free Swell Index for Clays
Authors: Sivapullaiah PV , Sitharam TG , Subba Rao KS 
Published: February 2009

Abstract
Free swell tests are commonly used for identifying expansive clays and to predict the swelling potential. The method as proposed by Holtz and Gibbs suffers from inaccuracies in volume measurement of dry powder in air. In this paper, a nondimensional modified free swell index is proposed, which removes the uncertainties present in the Holtz and Gibbs method. The modified free swell index is shown to bear unique correlations with liquid limit (volume basis) and percent swell of oedometer specimens compacted to proctor optimum conditions.
Heat and Moisture Transfer Characteristics of Compacted Mackenzie Silt
Authors: Evgin E , Svec OJ 
Published: February 2009

Abstract
The heat and moisture transfer characteristics of a silt from the Mackenzie River Valley have been determined in a laboratory investigation. A dual gamma-ray scanner was used to measure the changes in density and volumetric moisture content along the soil samples. The coefficients of soil-water diffusivity under isothermal conditions and under temperature gradients have been obtained. The development of a calibration curve for the analysis of gamma-ray readings has been described. The shortcomings of the procedures used for the measurement of transport coefficients have been discussed.
Assessing Frost Damage in Compacted Clay Liners
Authors: Benson CH , Chamberlain EJ , Erickson AE , Wang X 
Published: February 2009

Abstract
Methods used to assess frost damage (here defined as a large increase in hydraulic conductivity) in compacted clay liners are reviewed and evaluated using data collected from two test pads that were instrumented and then exposed to winter weather. The methods include comparisons of measurements of either water content and dry unit weight or hydraulic conductivity made before and after winter exposure. Field and laboratory methods of assessing hydraulic conductivity are considered.
The comparison shows that assessments based on water content and dry unit weight can be misleading. Assessments based on hydraulic conductivity are recommended. Field hydraulic conductivity tests can be useful provided the soil is not disturbed or smeared and the test method permits evaluation of liners partially penetrated by frost. In this study, however, the field tests yielded only qualitative results. Laboratory tests can also be used provided undisturbed specimens of sufficient size are collected. Specimens 70 mm in diameter were of adequate size in this study. Suitable specimens can be collected as blocks from thawed soil or with a core barrel while the soil is frozen. Collecting specimens in thin-wall sampling tubes (i.e., “Shelby” tubes) causes significant disturbance of thawed soil and thus is not recommended. Data are also presented to illustrate that laboratory tests should be conducted at effective stresses similar to those existing in the field.
Use of Stereophotogrammetry to Analyze the Development of Shear Bands in Sand
Authors: Harris WW , Viggiani G , Mooney MA , Finno RJ 
Published: February 2009

Abstract
Experimental results are presented from plane-strain compression of a fine-grained, water-saturated loose sand. Together with local measurements of boundary stresses and deformations, systematic analysis of photographs of the deforming specimen allowed for measuring deformations and computing strain fields inside and outside the shear band. The principles, details, and accuracy of the procedure are described. The capabilities of stereophotogrammetry are illustrated through typical results obtained from undrained and drained tests. A gradual transition from homogeneous deformation to temporary modes of localized strain to a highly localized strain field is systematically observed. Prior to strain localization in the region where the final shear band eventually forms, the soil contracts more than the rest of the specimen. As soon as the final band is fully formed, the soil inside the band either remains at constant volume or dilates. The nonuniformity of volumetric response throughout the specimen in globally undrained conditions implies there is water flow within the specimen.
Size Effects for Multi-Axial Tension Testing of HDPE and PVC Geomembranes
Authors: Merry SM , Bray JD 
Published: February 2009

Abstract
Geosynthetics may be subjected to multi-axial stress states from plane strain loading, such as dragdown along lined slopes and from out-of-plane loading conditions imposed by localized subsidence beneath waste containment cover and liner systems. The multiaxial tension test is useful in evaluating the performance of geosynthetics subjected to multi-axial stress states. However, widespread acceptance and use of this test has been slow due to the perceived requirement of a large-diameter test apparatus with its corresponding high cost. The development of a fully automated axisymmetric tension test apparatus and the results from laboratory testing of two geomembranes (HDPE and PVC) are presented in this paper. With this test apparatus, any one of four clamping rings of different diameters may be used to restrain the geomembrane during a particular test. Critical aspects of the test equipment and test procedures are described. The laboratory results indicate that use of a clamping ring with a significantly smaller diameter than currently required will provide comparable results provided that guidelines concerning the ratio of the clamping ring diameter to the material thickness are adopted and that stress-strain-time compatibility is maintained. This finding is supported by relevant membrane theory.
A New Boundary Stress Transducer for Small Soil Models in the Centrifuge
Authors: Pang PLR 
Published: February 2009

Abstract
The need to obtain reliable boundary stress measurements in centrifugal models of reinforced earth retaining walls has led to the development of a new form of boundary stress transducer. A rectangular sensitive face 100 mm long by 10 mm wide has been chosen to capture sufficient soil grains to give a representative soil pressure. Calibrations of the transducers under a layer of sand in the centrifuge were in good agreement with the deadweight calibrations. When used in a series of centrifuge model tests, the new transducers performed reliably in an environment that was anticipated to have a relatively large stress gradient.
A New Technique to Evaluate Erosivity of Cohesive Material
Authors: Rohan K , Lefebvre G , Douville S , Milette J-P 
Published: February 2009

Abstract
The paper presents a laboratory technique to evaluate the erosivity of cohesive soils, which permits, in addition to determining the critical shear stress, the observation of the rate and the mode of erosion throughout the test. The technique is similar to the pinhole test except that the hydraulic conditions are monitored at the entrance and exit of the specimen and that the eroded soil is recovered for the different stages of the test. The Moody diagram can be used to assess the evolution of the friction factor of the eroded surface during the test. Typical results are presented for tests on intact and sensitive structured clays of Eastern Canada. Erosion of intact clays has not been observed at the clay particle level but rather at the level of coarser grains or clay chunks associated with heterogeneities or fissures.
Centrifuge Testing of Vertically Loaded Battered Pile Groups in Sand
Authors: Zhang L , McVay MC , Lai P 
Published: February 2009

Abstract
Vertical load tests were carried out on 3 by 3 and 4 by 4 fixed head battered pile groups on a centrifuge. These tests simulated 0.43-m-wide by 13.7-m-long square piles founded in loose (Dr = 36%) and medium dense (Dr = 55%) sands at three-diameter spacing. The axial load and shear in each pile were measured during the tests. Numerical analysis was also carried out to predict the battered pile behavior using a coupled bridge foundation-superstructure finite element code (FLPIER). It was found that the vertical capacity of a battered pile group was slightly larger than that of a corresponding plumb pile group. The shear forces and bending moments in battered piles induced by design vertical loads were approximately one third of the ultimate lateral capacity.
The Application of Computer-Assisted Tomography in the Analysis of Fracture Geometry
Authors: Walters DA , Wong RCK , Kantzas A 
Published: February 2009

Abstract
An experimental study was conducted to investigate the surface characteristics of an oil sand fracture. The oil sand fracture was induced in core samples along the axis of the sample using the Brazilian tension test. A computer-assisted tomography scanning analysis was performed to determine the fracture geometry. The fracture was shown to be a variable aperture system that would have significant effects of the permeability of the fracture. The aperture distributions of the fractures were found to follow a log-normal distribution, similar to that of previously studied rock fractures.
Shear Strength Characteristics of Madinah Clay with Sand Compaction Piles
Authors: Gutub MZA , Khan AM 
Published: February 2009

Abstract
Shear strength characteristics of soft Madinah clay have been investigated from a series of consolidated undrained (CU) direct shear tests on specimens without and with circular sand drains of variable diameters. The investigation is conducted to study the shear strength behavior of soft Madinah clay in the presence of sand drains provided for the purpose of accelerating drainage and enhancing its response towards stabilization by preloading. The experimental shear strength test results have been compared with the theoretical values based on shear strength of clay-sand composite material derived from the shear properties of the individual materials. The shear strength parameters obtained from this study are expected to be of benefit and practical use for carrying out stability analysis of structures like embankments and foundations supported by clay and stabilized with vertical sand drains. Useful data were obtained showing a positive influence of the sand drain system on the enhancement of shear strength characteristics of soft Madinah clay.
Experience with the Use of Methylcellulose as a Viscous Pore Fluid in Centrifuge Models
Authors: Stewart DP , Chen Y-R , Kutter BL 
Published: February 2009

Abstract
In geotechnical modeling, the use of a pore fluid having viscosity greater than that of water is a well-established method of satisfying the scaling laws relating to movement of pore fluid through the soil during dynamic loading events. This has often been achieved with either silicone oil or mixtures of water and glycerol. However, there are a number of inherent drawbacks and difficulties in using silicone oil in particular, and this paper describes an alternative solution of hydroxypropyl methylcellulose (HPMC) in water that has been used recently with success. This paper presents test data documenting the variation in solution viscosity with concentration and temperature and the variation in specific gravity with concentration. The relative performance of the fluid is illustrated with data from two centrifuge model tests, one with pure water as the pore fluid and one with an HPMC solution having viscosity ten times that of water.