bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geo-Environmental Assessment of a Micaceous Soil for Its Potential Use as an Engineered Clay Barrier
Authors: Mohamed AMO , Yong RN , Tan BK , Farkas A , Curtis LW 
Published: February 2009

Abstract
The ability of the fine fraction of a natural micaceous soil in the Stanleyville area near Perth, Ontario, to retard an acidic waste leachate is examined. Batch and leaching column tests were used to investigate the retention capcity of the natural soil. To investigate the effect of ion competition on adsorption/desorption capacity of the soil, single and multi-components of Pb2+ and Zn2+ were used in batch experiments. The experimental results from column leaching tests were analyzed in terms of adsorption/desorption isotherms, breakthrough curves, and migration profiles of each specific ion in the influent. It was shown that the soil has high adsorption capacity for K+, Pb2+, and Zn2+ as indicated from the concentration profiles of the soil pore fluid with depth during leaching. At the same time, desorption of Na+, Mg2+, and Ca2+ occurred due to ion exchange.
The experimental data were analyzed using a phenomenological approach based on nondimensional analysis, analytical solution via Fourier series, and the root time method. The calculated diffusion parameters are presented and compared with the literature.
Treatment of Oil-Contaminated Soils for Identification and Classification
Authors: Meegoda NJ , Ratnaweera P 
Published: February 2009

Abstract
An experimental investigation was performed to evaluate the effects of oil contamination on soils and to establish a methodology to identify and classify contaminated soils. Identification and classification tests were performed before treatment, cleaning, stabilization, or disposal of contaminated soils.
There are no standards for identification and classification of contaminated soils. Fine-grained, oil-contaminated soils are often identified and classified as granular soils with large particle sizes and may result in selection of improper treatment techniques. In this study, four uncontaminated soils were first identified and classified; then, all four soils were mixed with 3% motor oil. The oil-contaminated soils were first tested for identification and classification and then treated by (1) heating in ovens at various temperatures (low-temperature desorption), (2) adding solvents (solvent extraction), and (3) adding surfactants (treatment with surfactants).
The processed soils were then reidentified and reclassified. Test results showed that treatment with a surfactant produced near-virgin soils for all four soil types. The solvent extraction was adequate only for the silty sand and the silty clay. The low-temperature thermal treatment was inadequate for all four soils. To further confirm the above test results, the low-plastic clay was mixed with 6% motor oil and the above test program repeated. This soil with a higher degree of contamination produced the same results. To provide an explanation for the change in soil behavior due to oil contamination, low-plastic soil was mixed with oil up to 70% by weight and Atterberg limit tests performed. It was concluded that fine-grained soils when contaminated with oil behave as granular soils with particle aggregation. Since soils in this study were artificially contaminated, one should exert caution when applying the results of this study to soils in contact with oil for many years.
Factors Affecting Sand Specimen Preparation by Raining
Authors: Rad NS , Tumay MT 
Published: February 2009

Abstract
Among the available procedures for obtaining reconstituted laboratory sand specimens, pluvial compaction appears to best simulate the natural processes leading to formation of sand deposits. Although widely used for a long period of time, effects of some components of the specimen preparation equipment (sand rainer) on the relative density of the specimen formed have not been comprehensively studied. This paper presents the results of an investigation aimed at studying these effects. The results obtained are used to provide a guide-line for design of a sand rainer.
An Automatic Feedback System for Resonant Column Testing
Authors: Morris DV 
Published: February 2009

Abstract
A test method and electronic circuitry is described that greatly simplifies measurement of resonant frequency in the resonant column test. It utilizes a feedback system to detect resonance automatically without requiring manual adjustment and also eliminates the need for a sine wave audio oscillator or oscilloscope. A constant and controllable strain level in the soil sample is ensured, irrespective of driving frequency or sample condition, by providing a voltage-limiting circuit within the system. The design described will automatically track and display variations in resonant frequency as a result of changes in applied cell pressure and/or strain level, etc.
In addition, double integration allows direct digital output of strain level to be continuously displayed. An alternative (and very rapid) method of measuring damping is also suggested.
Preliminary results are presented for tests performed in this way. An integrated package is shown that replaces the discrete components by a single unit.
Generalized Calibration of a Nuclear Moisture/Density Depth Gauge
Authors: Morris PH , Williams DJ 
Published: February 2009

Abstract
The application of nuclear moisture/density depth gauges to soil deposits has generally relied on calibration by direct correlation with measured values of moisture content and density. In very soft variable deposits such as coal tailings, direct calibration is not possible. A generalized calibration can be developed from first principles based on the elemental composition of the soil being tested and the application of existing theories. Density and moisture content calibrations are considered separately for two different access tubes, and reasonably reliable calibrations are obtained. In applying these calibrations, an iterative procedure is required since the moisture content has a direct bearing on the elemental composition of the moist soil. The paper gives an insight into the operation and important features of a nuclear gauge.
The Preparation of Hollow Cylinder Specimens from Undisturbed Tube Samples of Soft Clay
Authors: Talesnick M , Frydman S 
Published: February 2009

Abstract
The use of torsional-hollow cylinder testing apparatus for research into soil stress-strain behavior has grown over the past decade. Most studies have focused on sands or on cohesive materials reconstituted in the laboratory. Studies involving undisturbed soft clay have been neglected, in part due to the difficulties involved in specimen preparation.
The present paper describes a procedure for the preparation of hollow cylinder specimens of very soft undisturbed clay and their mounting in the triaxial chamber. The procedure involves the use of electrosmosis in order to allow “frictionless” cutting of soft saturated cohesive materials. The specimen is supported laterally, axially, radially, and tangentially throughout the entire procedure.
The procedure could easily be adapted for the preparation of specimens of soft clays for any geotechnical laboratory test.
Measurement of B-Values Less Than Unity for Thinly Interbedded Varved Clay
Authors: Eigenbrod KD , Burak JP 
Published: February 2009

Abstract
During testing of thinly interbedded varved clay from Thunder Bay, Northwest Ontario, in CIŪ-triaxial tests it was found that B-tests carried out following completion of the consolidation stages and prior to shearing never resulted in B-values close to unity. However, B-values close to 1 were obtained when B-tests were performed after failure. It was further detected from additional B-tests that B-values decreased with increasing stress levels. The test results will be presented and discussed with respect to the structure of the varved clay, which is characterized by thinly interbedded soft clay seams and stiff sandy silt seams.
Complex Stress Paths and Validation of Constitutive Models
Authors: Bianchini G , Saada A , Puccini P , Lanier J , Zitouni Z 
Published: February 2009

Abstract
The solution of complicated soil engineering and soil structure interaction problems requires the use of realistic constitutive equations and failure criteria. A recent international workshop held at Case Western Reserve University was aimed at assessing the predictive capability of presently available models for granular noncohesive soils. The results of tests conducted on hollow cylinders at Case and on cubes at the University of Grenoble were used to test the various models. This paper highlights some of the realities of soil testing when the equipment used induces different boundary conditions to the soil samples. It evaluates the predictions submitted to the workshop and examines the adequacy of the various classes of models in predicting simple and complicated stress paths using results obtained from standard tests.
Modified Testing Device to Evaluate MR Properties on Fly Ash Treated Subgrade Soil
Authors: Chang DT-T , Chiang C-E , Chang C-Y 
Published: February 2009

Abstract
The need to obtain reliable resilient modulus (MR) for fly ash treated subgrade soil in pavement thickness design in Taiwan prompted the modification of the existing standard testing device. In the modified device, a load cell and two linear variable differential transformers (LVDTs), conforming to TAI and AASHTO methods, were used to measure the axial load and deformation of specimen. To control the testing and data acquisition process, a computer program for MR of fly ash treated subgrade soil, “MRSS,” was developed using a 14-bit A/D convertor for data processing. The software is capable of simulating various testing conditions, such as load duration, varying repeated loads, and cycle duration. For monitoring purposes, the software is written to plot the stress-time and deformation-time curves, which were found to resemble the shape of a haversine curve. Through the calibration procedure, the performance of this modified testing device was found to be reliable and accurate.
An Automated Electropneumatic Control System for Direct Simple Shear Testing
Authors: DeGroot DJ , Germaine JT , Gedney R 
Published: February 2009

Abstract
This paper describes the design and implementation of an automated electropneumatic control system for direct simple shear testing of cohesive soils. The hardware and software used to perform automated application of consolidation increments and for subsequent constant volume shear of soil specimens is described in detail. Two servo-control algorithms are used to conduct a test, one for application of consolidation increments and another for maintaining constant volume during undrained shear. It is shown that a servocontrol system using a proportional controller can successfully control stress during consolidation increments but cannot control displacement by varying stress as required during undrained shear of cohesive soils. Results are presented which show that while the proportional controller can successfully perform displacement control for mechanical and hydraulic systems it cannot do so for more compliant pneumatic systems. This is primarily due to the fact that pneumatic systems are significantly less rigid due to the high compressibility of air as compared to the compressibility of mechanical systems and hydraulic fluids. While attempting to maintain constant height of the specimen, as is necessary to maintain constant volume during undrained shear, the pneumatic-based system falls into an irrecoverable oscillation of the vertical stress. It is shown that the undrained shear portion of a test required the implementation of the more sophisticated proportional plus integral plus derivative (PID) controller. Unlike the proportional controller, the PID controller easily maintains constant height of the specimen during undrained shear without instability in the vertical stress. Results are given comparing the performance of both the proportional controller and the PID controller during undrained shear of a cohesive soil specimen.
Stress Nonuniformities in Hollow Cylinder Torsional Specimens
Authors: Wijewickreme D , Vaid YP 
Published: February 2009

Abstract
Stress nonuniformities across the wall of hollow cylindrical torsional shear (HCT) specimens under generalized stress conditions are assessed taking into account the nonlinearity in soil behavior. The domain of stress space that results in acceptable levels of nonuniformities is thus delineated for a given specimen geometry. It is shown that previous analyses assuming linear elastic soil grossly overestimate stress nonuniformities in HCT specimens. The HCT device is thus suitable for investigating soil behavior under generalized stresses over a much larger domain of stress space than that thought earlier.
Microscopic Measurement of Sand Fabric from Cyclic Tests Causing Liquefaction
Authors: Ibrahim AA , Kagawa T 
Published: February 2009

Abstract
An experimental study was made to clarify and confirm: (1) the effects of a specimen preparation method on the fabric of sand; and (2) the change of sand fabric due to cyclic loading leading to liquefaction. Microscopic observations were made on the thin sections produced from sand specimens prepared by dry pluviation, dry vibration, and wet tamping methods. This study showed that dry pluviation tends to produce more “random” particle orientations and larger deviation of local void ratios than wet tamping. On the other hand, the dry vibration method produced intermediate results. This difference in fabric has the key impact on the liquefaction resistance of specimens prepared by different methods. Application of cyclic shear tends to alter the initial fabric of sand. For a “randomly” arranged sand mass, cyclic shear tends to line up the orientations of sand particles, resulting in less random arrangement of sand particles. For a “regularly” arranged sand mass, cyclic shear tends to diverge the orientations of sand particles. These findings help explain various static and cyclic behavior of sand.
Prediction of Embankment Settlements by In-Situ Tests
Authors: Bergado DT , Daria PM , Sampaco CL , Alfaro MC 
Published: February 2009

Abstract
The compressibility of soft Bangkok clay preloaded with an instrumented test embankment was studied using the results of a series of in-situ and laboratory tests. In the field, eight screw plate and eight pressuremeter tests were performed at four test levels in the subsoil. In the laboratory, twelve Rowe cell consolidation tests were carried out. The method of Asaoka (1978) was used in determining the coefficient of consolidation from the screw plate test. It was found that Cv values obtained from the Rowe cell consolidation tests were twelve times smaller compared to those derived from the screw plate tests. The soil parameters obtained from the two types of in-situ tests conducted in this study were then used to predict the settlement behavior of the two test embankments, one improved by prefabricated vertical drains (PVD), and the other, on unimproved ground. The difficulty associated with the proper choice of the drained modulus values are highlighted, and it was found that the predicted settlement magnitudes using elastic theory can vary considerably for the ratio of drained and undrained soil moduli, E′/Eu, ranging between 0.25 to 0.50. The undrained modulus from the screw plate test corresponding to the fitted data was found to be 1.38 times the undrained modulus from the pressuremeter test. General agreement with the observed settlement was found using the graphical procedure of Asaoka (1978) and adopting the coefficient of consolidation from the screw plate test.
Development of a Combination Inclinometer-Deflectometer and ADAAS
Authors: Kumbhojkar AS , Israel TD , Arnstan D , Lee SM 
Published: February 2009

Abstract
A newly developed transverse deformation gage, called the combination inclinometer-deflectometer, and special features of its automated data acquisition and analysis system (ADAAS) are described. The hybrid, two-in-one instrument and the ADAAS contribute to the enhancement of accuracy, reliability, and precision of ground movement measurements.
Bromhead Ring Shear Test Procedure
Authors: Stark TD , Vettel JJ 
Published: February 2009

Abstract
Existing test procedures and a proposed modification for the Bromhead ring shear apparatus were found to yield drained residual strengths higher than values back-calculated from field case histories. A new test procedure is presented that yields drained residual strengths that are in excellent agreement with field case histories. The new test procedure utilizes the unmodified Bromhead ring shear apparatus and limits the settlement of the top porous stone, due to consolidation and/or soil extrusion during drained shear, to 0.75 mm. Since the specimen is confined radially by the specimen container, limiting the settlement of the top porous stone minimizes the wall friction that develops along the inner and outer circumferences of the specimen. The reduced wall friction results in the lowest measured residual strength and the best agreement with field case histories.
A New Method for the Determination of Coefficient of Consolidation
Authors: Pandian NS , Sridharan A , Kumar KS 
Published: February 2009

Abstract
The time factor, T, and the degree of consolidation, U, from Terzaghi's theory of consolidation can be shown to have a bilinear behavior when plotted as log (U/T) versus log T. Using this property, a method is proposed for the evaluation of the coefficient of consolidation, Cv. The results obtained using the proposed method are compared with those using other methods in use. A fairly good agreement is obtained, which lends support to the validity of the approach suggested. This approach can be used in all cases including those in which popular methods like square root of time fitting method and logarithm of time fitting method fail.
Measurements of Matric Suction and Volume Changes During Inundation of Collapsible Soil
Authors: Tadepalli R , Rahardjo H , Fredlund DG 
Published: February 2009

Abstract
Reduction in soil volume due to inundation under a constant total stress is a phenomenon referred to as collapse. Collapse is exhibited by soils during a change of state from an unsaturated to a saturated condition. Several researchers have postulated various theories to explain collapse behavior. Recent published research has attempted to explain the collapse phenomenon using theories of unsaturated soil mechanics. However, the theoretical explanations require further verification by experimental data.
A simple experimental procedure is suggested in this paper to measure changes in matric suction and soil volume during inundation. The suggested measurements provide experimental data that can be used to verify the applicability of the unsaturated soil mechanics theories to collapsible soil behavior. Typical test results from this experimental program indicate that collapsible soil behavior can be explained using unsaturated soil mechanics theories.
An Injection-Correction System to Mitigate Membrane Compliance
Authors: Nicholson PG , Anwar HA , Seed RB 
Published: February 2009

Abstract
A computer-controlled injection correction system has been developed to continuously mitigate the adverse effects of membrane compliance for undrained testing of granular soils. The system was developed with the explicit idea that it could be quickly and easily adapted to almost any up-to-date triaxial testing apparatus. Methodology of the system is based on the direct and repeatable relationship between effective confining stress and volumetric compliance. A closed loop computer-controlled system continuously monitors changes in specimen effective confining stresses such that precalculated volumetric compliance errors may be continuously offset by injecting or removing volumes of water equal to those errors throughout the duration of each test. Implementation of the injection-correction system was demonstrated for a uniformly graded medium sand, exemplifying the potential usefulness of such a system.
Computer Automation of Conventional Triaxial Equipment
Authors: Sheahan TC , Germaine JT 
Published: February 2009

AbstractThis paper provides objective guidance on the conversion of existing manual triaxial testing equipment to computer control. An approach called adaptable automation is introduced to facilitate the conversion process. This approach consists of modifying the four basic building blocks of the triaxial system for integration into a computer-automated system and adding components needed for automation which were not part of the manual system. Recommendations are made on necessary changes to the triaxial building blocks, and examples are given from the actual conversion of a largely manual triaxial apparatus. New components required for the automated system are an analog-to-digital conversion device, digital-to-mechanical hardware, and a personal computer with test control software. Performance guidelines for selecting equipment are reviewed as are considerations when developing the software. Methods are described for evaluating the converted system's performance, and typical evaluation results are shown. The paper concludes that, while development of a prototype converted system can be costly and require considerable knowledge of system components, cost savings will be realized as additional prototype-based systems are brought online and system capabilities expanded. More importantly, the converted system allows existing customized testing procedures and hardware to remain in place.
Settlement of Compacted Clay in a Cyclic Direct Simple Shear Device
Authors: Chu H-H , Vucetic M 
Published: February 2009

Abstract
The results of 36 cyclic strain-controlled direct simple shear tests on a low-plasticity compacted clay are presented and analyzed. The tests were conducted in a Marshall Silver-type device, which utilizes the Norwegian Geotechnical Institute (NGI) type of short cylinder specimen confined in a wire-reinforced rubber membrane. Three degrees of compaction achieved by the modified compaction test are encompassed: (1) below the optimum moisture content, (2) at the optimum, and (3) above the optimum. All specimens were sheared under the same vertical consolidation stress. In each test the cyclic shear strain amplitude, γc, was controlled, i.e., the cyclic tests were strain controlled. The range of γc was between 0.008 and 4.6%. The test results show a very consistent behavior of the clay at all three moisture contents. At small cyclic shear strains below γc ≅ 0.1%, the stress-strain behavior is slightly nonlinear, i.e., close to linearly elastic, and the vertical settlement is negligible. In some tests such nondestructive behavior was recorded up to γc ≅ 0.2%, showing that for the clay tested, the volumetric threshold shear strain, γtv, ranges between 0.1 and 0.2%. At γc larger than γtv the cyclic stress-strain behavior becomes nonlinear and a continuous settlement with the number of cycles, N, occurs. The results do not show a clear relation between the rate of settlement with N and the degree of the compaction and moisture content. For different moisture contents, similar settlements were obtained for given γc and N. The study also shows how to arrange the specimen setup and measuring system to eliminate the effect of the simple shear apparatus compliance. In such an arrangement very small shear strains can be applied and successfully measured.