bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Adhesion in Chemically Grouted Geomaterials
Authors: Krizek RJ , Vipulanandan C 
Published: February 2009

Abstract
The mechanical behavior of a grouted geomaterial is influenced by both the cohesive properties of the grout and the bonding between the grout and the solid interface. Not only is the contribution of adhesion to the overall behavior not well understood, but there are no standard test methods to evaluate the adhesive properties at an interface. As one step toward better understanding this adhesive behavior, simple tests were developed to evaluate the adhesive strength under tensile, shear, and mixed mode loading conditions. Quartz rock and a grout mix consisting of sodium silicate, ethyl acetate, formamide, and water were used. Test results show that the bond strength changes with curing time and can be represented by a Mohr-Coulomb failure criterion.
Prediction of the Preconsolidation Pressure and Recompression Index of Soils
Authors: Nagaraj TS , Srinivasa Murthy BR 
Published: February 2009

Abstract
Based on the generalized compressibility equation a procedure is given to estimate the preconsolidation pressure and the recompression index of stress and time dependent overconsolidated soils. This is based on knowledge of (1) the in-situ void ratio, (2) the liquid limit of the soil, (3) the in-situ overburden pressure, and (4) the specific gravity of the soil solids. Estimates of these consolidation parameters, which often are sufficiently accurate, can be obtained without carrying out consolidation tests. The estimated values for specific soils are compared with published data.
Cavity Expansion Tests in a Hollow Cylinder Cell
Authors: Juran I , BenSaid MA 
Published: February 2009

Abstract
This paper presents the use of the hollow cylinder cell in investigating, under laboratory controlled conditions, the response of saturated, consolidated fine grained soils to a cavity expansion. The hollow cylinder cell concept developed originally by Kirkpatrick was adapted to perform cylindrical cavity tests in annular soil specimens with measurement of the excess pore-water pressure generated in the surrounding soil. This modified hollow cylinder cell was also used to study the consolidation of the soil around an expanding cylindrical cavity under a constant cavity pressure and to evaluate available procedures, which can be used to obtain the soil hydraulic conductivity. The equipment, testing procedures, and analysis of both expansion and consolidation test results are discussed.
Triaxial Testing of Brittle Sandstone Using a Multiple Failure State Method
Authors: Cain P , Yuen CMK , Le Bel GR , Crawford AM , Lau DHC 
Published: February 2009

Abstract
The first phase of a recent research program undertaken to investigate sandstone/methane outbursts in coal bearing rocks required the use of a sandstone reference material in the development and trial of the testing procedures to be used. This was because the number of specimens of outburst-prone rocks from the affected mine was limited. Thus another goal of the first phase was to determine a triaxial testing method for characterizing rock properties that minimized the number of specimens required. The International Society for Rock Mechanics (ISRM) multiple failure state method is attractive in this regard because an approximate strength envelope can be determined from a single specimen.
In this test program however the brittle nature of the reference material made control of failure by monitoring axial strain (the ISRM method) impossible; specimens always failed at the first, low or zero confinement, stage. An alternative method of detecting imminent failure in the specimen was developed and applied, yielding results almost identical to those obtained by conventional single state testing.
Differential Flow Patterns Through Compacted Clays
Authors: Peirce JJ , Sallfors G , Ford K 
Published: February 2009

Abstract
The determination of the hydraulic conductivity of compacted clays is vital when the clay is to be used as a liner for contaminant of hazardous waste. Therefore different types of permeameters were used and modified to investigate the homogeneity of a compacted specimens.
Flexible wall and fixed wall permeameters were modified using multiple ring bases to determine the magnitude of differential flow patterns during hydraulic conductivity testing. The hydraulic conductivity was calculated for different portions of the specimen. The outer ring of the specimen was found to have a permeability two to five times larger than that of the core of the specimen, resulting in an overall permeability, which was 50 to 100% higher than that of the core of the specimen. Thorough determination of the variation of the density within a specimen does not explain the variation of the hydraulic conductivity. The clay near the periphery is apparently exposed to a somewhat different type of compaction resulting in a different structure of the clay and thus a higher permeability. Tests with a 19 port base indicated that isolated areas could contain channels where major flow takes place.
Advantages of Midheight Pore Pressure Measurements in Undrained Triaxial Testing
Authors: Fourie AB , Xiaobi D 
Published: February 2009

Abstract
Most soil mechanics laboratories still prefer the use of rough end platens during triaxial testing despite an awareness that nonuniform stress conditions occur within the soil specimen. This practice may to some extent be due to a lack of awareness of the magnitude of inaccuracies which may result. This paper describes results from unconsolidated undrained triaxial compression and extension tests in which pore pressures were monitored at the specimen base and at midheight using a circumferentially mounted miniature transducer. The rate of imposed displacement was varied by two orders of magnitude. The significance of displacement rate and specimen end condition is illustrated by presentation of resulting stress ratios and stress paths. Base measured pore pressures were found to be up to 50% higher than the midheight values, depending on the testing rate used. The results indicated that currently accepted criteria for the determination of acceptable displacement rates are adequate.
Measuring Inherent Load-Extension Properties of Geotextiles for Design of Reinforced Structures
Authors: Wu JTH 
Published: February 2009

Abstract
Existing test methods for measuring the load-extension properties, including the stiffness and the ultimate strength, of geotextiles as they are subjected to confining pressures are reviewed and critically evaluated. In addition, a new test method which surmounts the drawbacks of the existing methods is presented. The new method has three distinct characteristics: (1) it is an “element” test, thus the load-extension properties determined from the test are the inherent properties of the geotextile; (2) the test measures the confined stiffness and strength of geotextiles without inducing soil-geotextile interface adhesion, thereby simulating the predominant operational condition in typical geotextile-reinforced soil structures; and (3) the stiffness and strength obtained from the test are conservative values if soil-geotextile interface slippage does occur in a reinforced structure. The new test method offers a unified and more rational method for determining the load-extension properties of geotextiles in the design and specification of geotextile-reinforced soil structures.
Swelling/Shrinkage Characteristic Curve of Desiccated Expansive Clays
Authors: Hanafy EADE 
Published: February 2009

Abstract
The change in void ratio with change in water content of expansive clayey soils due to soil desiccation and water absorption has been identified as the integral/combined curve referred to as S-curve, which describes both swelling and shrinkage paths in the form of the void ratio versus moisture content relationship.
General characteristics of the S-curve and its determination procedure are described in detail in this paper, including presentation of the theoretical considerations, phase diagrams for both swelling and shrinkage conditions, and the primary paths of the S-curve.
The swelling/shrinkage characteristic curve in the form of the volume change versus moisture content relationship is also presented as a swelling potential chart that can be used to evaluate the swelling potential of desiccated expansive clays.
A New Technique for Measuring the Roughness Profile of Rock Joints
Authors: Lee D-H , Juang CH 
Published: February 2009

Abstract
This technical note describes a new technique for measuring the roughness profile of rock joints or discontinuities. This new technique involves use of a laser displacement meter (LDM) and a linear variable differential transformer (LVDT). The technique improves precision and speed of the measurement. A comparison of this technique with existing methods for measuring the roughness profile is presented.
Soil Column Drainage Modelling Using a Geotechnical Centrifuge
Authors: Cooke AB , Mitchell RJ 
Published: February 2009

Abstract
Equipment has been developed to facilitate supplying a soil column with water or draining a soil column under conditions of constant head while the soil column is under centrifugal forces in a geotechnical centrifuge. Accurate monitoring of the water mass transfer is also facilitated by the equipment. At the completion of a modelling sequence, the soil column may be partitioned for moisture content and chemical analysis with minimal disruption of the moisture content profile. Some preliminary modelling results are included in the paper.
Design Basis for Cells Measuring Shear Stresses in an Interface
Authors: Askegaard V 
Published: February 2009

Abstract
An expression is derived for the measuring error that must be expected when measuring shear stresses in an interface, that is, on foundations, buried pipes, silos, and so forth, by means of a plate-type shear cell fixed along the edge. A prototype cell of this type has been produced and calibration tests carried out using two types of calibration equipment; in the first a uniformly distributed shear load is transmitted to the shear cell while in the second, the shear stress is transmitted through a particulate medium to the wall in which the shear cell is mounted. The accordance between the theoretically predicted measuring error, using the expression derived, and the experimentally determined measuring error is good.
Testing Using a Large-Scale Cyclic Simple Shear Device
Authors: Amer MI , Aggour MS , Kovacs WD 
Published: February 2009

Abstract
Cyclic simple shear testing is considered to be one of the most appropriate ways of reproducing in the laboratory the stresses that would be experienced by an element of soil in level ground subjected to earthquake loading. In the last few years cyclic simple shear testing has been analyzed experimentally and theoretically, and the advantages and limitations of the test presented. The main drawback concerns the lack of complementary shear stresses on the specimen vertical boundary and thereby a selection of the proper specimen size, that is, proper diameter versus height ratio must be carefully considered. The nonuniformity of the strain and stresses in the specimen most likely increases as the specimen diameter versus height ratio decreases. To investigate the specimen size effect on the primary dynamic (cyclic) soil properties, namely, the shear modulus and damping, a large-scale simple shear apparatus was constructed. In it, specimens having diameters from 7.6 to 30.5 cm (3 to 12 in.) and heights from 0.64 to 10.2 cm (¼ to 4 in.) could be tested. Thus a wide range of diameter to height ratios could be obtained. The new testing device, its control system, and the method of preparation and installation of the soil specimens for such a large-scale device are presented and discussed. In addition, a cyclic testing program was conducted on sand and some examples of the data obtained are presented as well.
Significance of Specimen Preparation Upon Soil Plasticity
Authors: Armstrong JC , Petry TM 
Published: February 2009

Abstract
The limits of soil behavior defined by Atterberg and refined by others and the indices resulting from their determination have become vastly important to the design process in geotechnical engineering. The methods utilized to determine these properties are under scrutiny because of the widely varying results that are found. One of the primary sources of this variance was thought to be the modes of specimen preparation.
The research reported on in this paper was conducted to determine the extent of the property variance caused by this part of the testing and to find a specimen preparation that could lead to the most uniform and acceptable result. Thirteen different specimen preparation procedures were studied, and the resulting limits and indices analyzed. The procedure found to be most successful was that affecting the double water layer situation the least. The variance noted was great enough to cause some samples to move from a CH to a CL classification. In all cases the variance noted was significant. The conclusions include recommended procedures and recommendations for further study.
Dynamically Loaded Pile in Overconsolidated Clay
Authors: Muster GL , O'Neill MW 
Published: February 2009

Abstract
A series of dynamic axial loading tests were conducted on a 273-mm-diameter steel pipe pile driven 13.4 m into a layered deposit of overconsolidated clay. A linear inertial mass vibrator was used to provide frequency sweep loadings from frequencies above to frequencies below the fundamental frequency of the pile-soil-cap system at three magnitudes of dynamic load. Superposition of a dynamic component of load of about 5% of the static capacity of the pile on a static biased compressive load resulted in slight nonlinear behavior and induced some residual increase in flexibility of the system. Two existing analytical models were studied in light of the measured performance of the pile and were found to yield appropriate solutions provided the soil parameters were selected properly.
A New Apparatus for Investigating the Stress-Strain Characteristics of Sands
Authors: Alarcon A , Chameau JL , Leonards GA 
Published: February 2009

Abstract
A new hybrid resonant column/torsional shear apparatus has been developed, which permits the determination of dynamic soil properties on a single solid or hollow cylinder specimen over the entire range of shear strain amplitudes of engineering interest, that is, from 10−4 to 10%. The main characteristics of both the resonant column and torsional shear tests are presented with emphasis on those factors that influenced the design of the new apparatus. The new apparatus is described in detail, and representative test results to demonstrate its capabilities are presented.
On the Importance of Rate of Strain in the Consolidation Test
Authors: Crawford CB 
Published: February 2009

Abstract
In many consolidation tests the imposed rate of strain is several orders of magnitude faster than field rates even though it is well known that some of the parameters derived from laboratory tests are strain rate dependent. For this reason it is essential that the standard test procedure provides adequate guidance on the acceptable rate of strain for various classes of natural soils. This paper reviews the problem, describes the approach taken by several authors, and suggests further research that will lead to improvements in consolidation technology.
Methylene Blue Adsorption as a Rapid and Economical Method of Detecting Smectite
Authors: Higgs NB 
Published: February 2009

Abstract
Methylene blue adsorption (MBA) is found to be an effective method of indicating when smectite (group name for the mont-morillonite minerals) is present in major amounts in mudrocks or along discontinuities. The basic relationship is that MBA values greater than 15 indicate that smectite is present as 15 is the maximum value found for illite, the next most adsorptive mineral as compared with smectite. For example, the Pierre shale, which typically contains 30 to 40% smectite along with 25 to 45% mixed-layered smectite-illite has a MBA value of 48.5; whereas, the Palastine shale, which has illite rather than smectite as its chief component has a MBA value of only 7.0. The abundant smectite constituted samples are of materials involved either in slope stability or slaking in foundations, or both. MBA requires only a 2-g specimen, and thus clays along discontinuities and clays along thin slip zones of slides can also be analyzed as to type of clay. The method is less expensive than X-ray diffraction analyzes but also can supplement X-ray diffraction investigations.
Determination of Consolidation Properties for Very Soft Clay
Authors: Tan S-A , Tan T-S , Ting LC , Yong K-Y , Karunaratne G-P , Lee S-L 
Published: February 2009

Abstract
A finite strain consolidation test with a constant surcharge to determine the compressibility (e − σ′) and permeability (e − k) relationships of very soft clay is proposed. The method uses Gammarays and pore pressure transducers to measure density and pore pressure profiles, respectively, at various times of the test without hindering the consolidation process. The constant surcharge applied accentuates the changes in density and pore pressure profiles enabling them to be measured reliably. These profiles are then used to determine the compressibility and permeability of the soft clay. A test is carried out to extract these properties, which are used in a finite strain consolidation theory to predict the settlement, void ratio, and pore-pressure distributions of other tests done under different initial and boundary conditions. The predictions are found to agree well with the experimental data, thus suggesting that the properties determined are accurate.
Laboratory Investigation of Earth Walls Simultaneously Reinforced by Strips and Random Reinforcement
Authors: Arenicz RM , Chowdhury RN 
Published: February 2009

Abstract
The performance of reinforced earth structures depends, among other factors, on the shear strength of the backfill material used in construction. The shear strength can be enhanced by the use of random reinforcement. This paper presents the result of laboratory investigations concerning the effects of several types of random reinforcement on soil strength and, in particular, on the performance of reinforced earth model walls.
Six series of experiments were conducted, in which a medium sand randomly reinforced by various metal particles was used as a backfill material for construction of 32 model walls. In construction of the walls standard reinforcement (horizontal metal strips attached to facing units) was used as well. The results obtained from shear box tests and from observation of model wall failures indicate that the presence of random reinforcement could lead to a significant increase in the critical height of model walls. An increase of up to 13% was observed as a result of adding only 0.5% of random reinforcement to the sand used for the construction of model walls. It was also found that fiber-like shapes of random reinforcement particles give a more significant increase in the soil strength and critical height of walls than other shapes tested. It might be reasonably expected that a small quantity of similar random reinforcement used in full-scale constructions could lead to a significant increase of their design height or, alternatively, to a decrease in volume of standard reinforcement needed.
A Device for Evaluating One-Dimensional Compressive Loading Rate Effects
Authors: Farr JV , Woods RD 
Published: February 2009

Abstract
It has long been suggested that the one-dimensional or uniaxial strain response of most soils subjected to high-intensity transient loads differs from the response measured under static conditions. As the time to peak pressure decreases, most soils exhibit a stiffening of the loading stress-strain response. That stiffening is usually referred to as a time or loading rate effect. Some researchers have suggested that, as the time to peak pressure approaches the submillisecond range, a drastic increase (up to tenfold) in the loading constrained modulus occurs for partially saturated granular soils under unconsolidated-undrained conditions. The existence of this effect has been the subject of debate.
A test device was developed at the U.S. Army Engineer Waterways Experiment Station using explosives to obtain submillisecond loading times to peak pressures of approximately 138 MPa (20 000 psi). By using state-of-the-art measurement and acquisition systems, an accurate measurement of the uniaxial stress-strain response to submillisecond loadings was obtained. This paper presents the details of that device and the associated electronic measurement and acquisition systems, testing techniques, data interpretation, and typical test results used in assessing loading rate effects of a partially saturated carbonate sand. Results showed that a drastic stiffening did not occur for this material as the time to peak pressure approached the submillisecond range. Instead, a gradual stiffening occurred and the basic shape of the stress-strain curve was maintained.
Strain-Rate Influence on the Interpretation of Plate Bearing Tests
Authors: Georgiadis M 
Published: February 2009

Abstract
The effect of the rate of load application (or settlement application) during a plate bearing test, on the load-settlement relationships is examined. A series of plate bearing tests on clay demonstrated that when the loading rate increases the bearing capacity and the stiffness also increase. To quantify this increase, an exponential foundation model was proposed, which considers the clay as a viscous material. This model proved very satisfactory in determining the load-settlement response of a bearing plate at any loading rate, provided that the response of the same plate at a different loading rate and the basic geotechnical properties of the clay are known. The importance of the loading rate depends on the viscosity of the clay, which is affected by the plasticity, the water content, and the undrained shear strength.
Automatic Back-Pressure Saturation Device for Triaxial Testing
Authors: Brandon TL , Duncan JD , Cadden AW 
Published: February 2009

Abstract
If back pressures are applied to unsaturated triaxial specimens too rapidly, the specimens may be overconsolidated by the temporary application of effective stresses that are higher than intended. This is dangerous because the strengths of the specimens will be higher than they would be without this inadvertent overconsolidation. An automated device has been developed to ensure that the specimen will not be overconsolidated during saturation. This device continuously monitors the maximum effective stress in the specimen and optimizes the rate at which the cell pressure and back pressure can be increased without exceeding an allowable effective stress at any point in the specimen. Tests were performed on three soils with different grain sizes and degrees of saturation to investigate the effectiveness of the device under varying test conditions. The tests show that the device is capable of applying back pressures with a minimum of operator attention, and that it eliminates the possibility of inadvertently overconsolidating specimens during back-pressure application.
Transition from Maximum Tension Line to Actual Failure Surface in Reinforced Soil Model Walls
Authors: Arenicz RM 
Published: February 2009

Abstract
This paper presents the results of laboratory tests conducted on reinforced soil model walls. The effect of model height on distribution of tensile stress in an instrumented reinforcement strip was investigated. It was found that, with increasing height of wall, a continuous redistribution of tensile stress had occurred with the point of maximum tension moving towards the actual failure surface of the model. On that basis, a correlation between the position of maximum tension in reinforcement and the overall safety factor of model walls was investigated. General and specific equations of maximum tension line in terms of wall height and safety factor were suggested.