bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Fines on Monotonic Undrained Shear Strength of Sandy Soils
Authors: Thevanayagam S , Ravishankar K , Mohan S 
Published: February 2009

Abstract
Shear strength of liquefied sands is an important component in seismic slope stability evaluation. Experimental data on a host sand mixed with different amounts of fines content and a careful analysis of other available steady state strength (Sus) data show that fines content and relative density play important roles affecting Sus. Fines content is found to be the major factor affecting Sus. When the Sus data for sands are grouped into (a) relatively clean sands (&lt;12% fines), (b) silty sands (12 to 32% fines), and (c) silts or sandy silts (&gt;50% fines) at the same relative density, relatively clean sands show the highest Sus. Silts show the lowest Sus. Silty sands show intermediate strengths. Based on this data, lower-bound relationships are proposed for Sus as a function of Dr and fines content.
Grain-Size Distribution of Granular Soils by Computer Vision
Authors: Raschke SA , Hryciw RD 
Published: February 2009

Abstract
A semi-automated technique for obtaining the grain-size distribution (GSD) of granular soils using computer vision is presented. Backlighted digital images of a soil specimen dispersed over a glass specimen plate are acquired at three different magnifications. Images of the specimen are acquired by placing the specimen plate randomly beneath the field of view of a charged-coupled device (CCD) video camera. The size of particles with projected areas from 50 to 2000 pix2 is measured in each image. Multiple images are acquired at each magnification until the measured size distribution of particles counted at that magnification stabilizes. Probabilistic corrections are then used to obtain a statistically unbiased GSD from the image data obtained at all three magnifications. A comparison of GSD data for two uniform and two nonuniform soils using both computer vision and sieving is presented.
Testing of Reinforced Slopes in a Geotechnical Centrifuge
Authors: Zornberg JG , Mitchell JK , Sitar N 
Published: February 2009

Abstract
An evaluation of the use of centrifuge modeling as a tool for analyzing the behavior of reinforced soil slopes is presented in this paper. A review of the state-of-the-art indicates that previous centrifuge studies have focused mainly on the performance of reinforced soil vertical walls and that limit equilibrium approaches (used in the design of reinforced soil slopes) have not been fully validated against the failure of models in a centrifuge. As part of an evaluation of the conditions of similarity governing the behavior of reinforced soil structures at failure, scaling laws are specifically derived by assuming the validity of limit equilibrium. It is demonstrated that an Nthscale reinforced slope model should be built using planar reinforcements having 1/N the strength of the prototype reinforcements in order to satisfy similarity requirements. A description of the experimental testing procedures implemented as part of a recent centrifuge testing program is presented, and an example dataset from this investigation is used to illustrate typical results. These include the g-level at failure, visual observation of failure development, and post-failure analysis of reinforcement breakage. The pattern observed in the geotextile reinforcements retrieved after testing indicates that the boundary effects were negligible.
Measurement of the Contact Angle of Water on Geotextile Fibers
Authors: Henry KS , Patton S 
Published: February 2009

Abstract
The contact angle of water on geotextile fibers significantly influences capillary behavior. Measurements of the dynamic contact angle of tap water on geotextile fibers are reported for two geotextiles, as received from the manufacturer and after they had been treated (cleaned). There is considerable hysteresis between advancing and receding contact angles, as expected. Fibers from one geotextile have significantly lower contact angle cosines than the other, indicating that it is less wettable. The cleaning of geotextiles resulted in significant reduction in the advancing contact angles of fibers from one of the geotextiles but not the other. The heights of water capillary rise in strips of the geotextiles were also measured. Results showed that the contact angle measurements are helpful; but, information on pore sizes is also needed to predict capillary behavior.
Interpretation of Model Pressuremeter Test Using Automated Clay Calibration Chamber Data
Authors: Penumadu D , Chameau J-L 
Published: February 2009

Abstract
The details of an automated flexible wall calibration chamber test system developed to perform strain-controlled model pressuremeter testing in cohesive soil are presented. The procedure involved in obtaining uniform speciments by consolidating a slurry of kaolin in two stages is described. The importance of automated control (electro-pneumatic control for this study) to perform second stage K0 consolidation accurately is shown. Typical test results are presented along with the evaluation of undrained strength, initial shear modulus, stress-strain variation, limit pressure, and horizontal stress using various methods of interpretation. Unload-reload loops were performed, and the shear modulus values were compared with the deduced values from the initial loading curve. Interpreting the pressuremeter test data using the Marquardt-Levenburg algorithm is presented. The improvements to the Simplex method are identified along with the effect of the reference state. A new procedure for incorporating the unloading portion in interpreting the pressuremeter test data is developed along with the detailed comparisons.
Computer Vision-Based Technique to Measure Displacement in Selected Soil Tests
Authors: Obaidat MT , Attom MF 
Published: February 2009

Abstract
The potential of normal case photography using charge-coupled-device (CCD) cameras to extract deformation (strain) in soil specimens of two soil tests, i.e., the unconfined compression test and the direct shear test, was investigated. A PC-based digital vision system was used to obtain accurately measured linear displacement. Using remolded soil specimens, comparisons between displacement measurements using ASTM conventional methods and the normal case photography method showed that use of the latter method is promising and could be used as a substitute for strain gages. Experimental investigation showed that differences between displacement measurements using conventional ASTM procedures and computer vision technique were consistently within 0.04 ± 0.15 to 0.3 ± 0.23 mm for unconfined compression tests and direct shear tests, respectively. This was compatible with the image scale where one pixel on the image domain was equivalent to about 0.4 mm on object space coordinates. Statistical correlations between strains by the two methods supported this result. Image scale and resolution were found to be the two major factors affecting the accuracy of the measurements. The results of this work are expected to open the door for geotechnical engineers and agencies responsible for soil testing standards to incorporate image-based analysis in soil testing. This will indeed bridge the gap between manual and fully automated soil testing measurements.
Theoretical Evaluation of the Transient Response of Constant Head and Constant Flow-Rate Permeability Tests
Authors: Zhang M , Takahashi M , Morin RH , Esaki T 
Published: February 2009

Abstract
A theoretical analysis is presented that compares the response characteristics of the constant head and the constant flow-rate (flow pump) laboratory techniques for quantifying the hydraulic properties of geologic materials having permeabilities less than 10−10 m/s. Rigorous analytical solutions that describe the transient distributions of hydraulic gradient within a specimen are developed, and equations are derived for each method. Expressions simulating the inflow and outflow rates across the specimen boundaries during a constant-head permeability test are also presented. These solutions illustrate the advantages and disadvantages of each method, including insights into measurement accuracy and the validity of using Darcy's law under certain conditions. The resulting observations offer practical considerations in the selection of an appropriate laboratory test method for the reliable measurement of permeability in low-permeability geologic materials.
Design of Polyvinyl Chloride Tar Mixes for Resistance to Permanent Deformation
Authors: Singh G , Dhliwayo MW 
Published: February 2009

Abstract
The problem of shortages of normally acceptable materials can be alleviated by using low- and marginal-quality materials through selective use of stabilization. In areas where coal is prevalent coke-oven tar, modified with small quantities of polyvinyl chloride (PVC), can be mixed with sand to produce good paving material. Static and dynamic tests performed on PVC tar-sand mixtures show that the addition of PVC produces vast improvements in the Marshall properties and the resistance to permanent deformation, with only marginal influence on the compatibility. Mix design based on repeated loading tests at various temperatures suggests that the addition of PVC reduces the optimum binder content.
Phenomenological Study of Model Piles in Sand
Authors: Yazdanbod A , O'Neill MW , Aurora RP 
Published: February 2009

Abstract
A device is described whereby sand can be confined in a depthwise variable manner to permit simulation of lateral earth pressures to depths simulating driving depths of piles. Instrumented model piles were driven into a quartz sand placed at two different densities in the device, and load transfer patterns were measured for varying depths of penetration for compressive and uplift loading. In most respects the load transfer patterns were similar to those measured in full-scale tests in sand.
Measurement of Lateral Stress Around Multihelix Anchors in Sand
Authors: Clemence SP , Pepe FD 
Published: February 2009

Abstract
The lateral stress regime around a one-quarter scale model triple-helix anchor was measured with diaphragm-type soil stress cells. Laboratory anchor pullout tests were run in a dry, uniformly graded sand at two different depths and relative densities. Lateral stresses were measured before and after installation of the helical anchor, at anchor failure, and continuously during the application of the uplift load. Results indicated that helical anchor installation causes increase in lateral stress around the anchor. Large increases in stress were observed in dense soils. In addition, lateral stresses increased as the anchor was loaded to failure. This behavior was attributed to arching stresses and soil dilatancy developing in the sand as it was sheared by the anchor. The magnitude of these increases was found to depend on the relative density of the sand. Based on the test results, values of the coefficient of lateral stress at failure kF were calculated for several densities and depths. The calculated kF values were found to be 30 to 40% lower than those proposed by Meyerhof and Adams for buried foundations. These lower values are due to the shearing disturbance during anchor installation.
Filter Openings Measured by a Suction Method
Authors: Dennis CW , Davies PA 
Published: February 2009

Abstract
A laboratory method is presented for determining the distribution of opening sizes within initially water saturated geotextiles under simulated soil loading, the principle being to measure air entry values over a range of applied suctions. Construction and use of the apparatus concerned are outlined while the analysis of data so obtained is given in detail. Results from two geotextiles are presented, and a comparison is made with data obtained by another method.
Evaluation of Schmidt Hammer Rebound Hardness Test Holders
Authors: Gunsallus KL , Kulhawy FH , O'Rourke TD 
Published: February 2009

Abstract
An evaluation is made of three different holders for Schmidt hammer tests on rock core in the laboratory, including steel angle, V-notch, and semicircular groove holders. The differences are small, but it is shown that the V-notch holder gives consistently higher rebound hardness values. It is also easier and more economical to build. These qualities indicate that the V-notch holder would be a better selection for conventional use.
Laboratory Evaluation of Soil Suction Components
Authors: Edil TB , Motan SE 
Published: February 2009

Abstract
A laboratory evaluation of the soil-water potential components (total, matrix, and osmotic suction) is presented using a series of clay specimens statically compacted dry- and wet-of-optimum. In unsaturated soils, moisture movement is controlled either by total or matrix suction depending upon the degree of unsaturation, whereas deformation and strength behavior is controlled primarily by matrix suction. Therefore, it is imperative to evaluate the suction components separately. Significant osmotic suction component was induced as a result of incomplete leaching of the sodium and calcium surface-saturated Grundite (initially prepared by treating the clay slurry with strong sodium chloride and calcium chloride solutions to achieve mass action of cations). Matrix suction was induced by equilibrating the specimens to different pressures on a ceramic-plated extractor. At equilibrium, total suction of the specimens was measured using a Peltier type psychrometer. Test results indicate the use and limitations of the psychrometric method and the interrelationship of suction components. Measured values of the total suction by the psychrometric method indicate more consistent results at moisture contents above the plastic limit. Below the plastic limit, the osmotic component, as deduced by the difference between total and induced matrix suctions, tends to decrease gradually with increasing matrix suction. It is found that the osmotic suction can be measured most suitably on pore-water extracts using psychrometry.
Suggested Method for Estimating the In-Situ Modulus of Deformation of Rock Using the NX-Borehole Jack
Authors: Heuze FE 
Published: February 2009

Abstract
The NX-borehole jack is a widely used tool for estimating the deformability of rock masses in-situ. It applies unidirectional pressure to the walls of a rock borehole by means of two steel platens. In theory, the analysis of test data is straightforward: the modulus estimate requires a record of applied hydraulic pressure versus borehole diameter change, and a knowledge of the rock's Poisson's ratio. In practice, the above procedure, using the original theoretical formula, frequently has resulted in computing a material modulus that was demonstrably too low.
Today, it is finally understood how one or more of the following factors can provide a low modulus estimate: (1) the longitudinal outward bending of the jack plates which gives artificially high readings of the displacement gages and (2) the mismatch between borehole and jack platen radii, which would negate the full platen/rock contact assumed in the original analysis, and (3) tensile cracking of the intact rock or tensile opening of natural joints around the borehole under the jack.
The detailed discussion of the theoretical developments is contained in a separate paper, which should be a complement to this draft. This document outlines a suggested procedure for testing with the NX-jack, and analyzing the test results in a medium which is assumed to be isotropic, linear, clastic, and homogeneous.
A Direct Tensile Loading Apparatus Combined with a Cubical Test Cell for Testing Rocks and Concrete
Authors: Meier RW , Ko H-Y , Sture S 
Published: February 2009

Abstract
A novel tensile loading apparatus is described, which when used in conjunction with an existing fluid-cushion cubical test cell, allows the simultaneous application of a pure principal tensile stress and transverse principal compressive stresses to concrete and rock specimens with a minimum of boundary constraints. A tensile stress is applied along one axis of a cubical specimen through brush platens glued to the specimen surface while compressive stresses are applied along the two remaining axes through fluid cushion systems. In this manner, three totally independent principal stresses can be applied with virtually no tangential surface tractions so that the actual stress state in the specimen is identical to the applied stresses. Stress-strain response curves and strength relations from biaxial tension-compression tests on Indiana limestone and steel-fiber reinforced concrete are presented as examples of the capabilities of the new device.
Axial Pile Loading Test—Part 1: Static Loading
Authors:   ISSMFE Subcommittee on Field and Laboratory Testing
Published: February 2009

Abstract
The International Society of Soil Mechanics and Foundation Engineering established a technical committee to develop manuals for field and laboratory geotechnical tests. As one of these, recommendations on axial pile loading tests are presented to the profession resulting from four years of worldwide discussion among piling experts of 16 countries. The text is supplemented by notes that indicate details on which no unanimous decision could be obtained.
The document recommends requirements on the test device and the test proceeding. Further, the evaluation of the determination of the test limit load is included because it was felt that much uncertainty would remain if the type of engineering judgment on the test results would be kept out.
The Effect of Clay Content on Liquid Limit from a Fall Cone and the British Cup Device
Authors: Budhu M 
Published: February 2009

Abstract
The many shortcomings of the Casagrande cup device, used almost univerally to determine the liquid limit of soils, led to the investigation of fall cones as alternatives. In two of the four types of fall cones in use, investigators have shown that the differences between fall cone liquid limit values and cup liquid limit values were not large. Evidence is produced to show that the fall cones of the same cone angle would give identical results if the appropriate depth of penetration is specified. Tests conducted using a British/French fall cone and a British cup device reveal that the difference in liquid limit values between these two devices is related to the amount of clay in the soil. A one point fall cone method is shown to be sufficiently accurate to deduce the liquid limit of soils. The fall cone method is a rational alternative to the cup device, and since engineers are interested in strength, the liquid limit could perhaps be defined as the water content at which a soil would have a specific undrained shear strength (say 1kN/m2).
An Underwater Instrument for Determining Bearing Capacity of Shallow Marine Sediments
Authors: Circé RC 
Published: February 2009

Abstract
A small, portable, underwater instrument for measuring carbonate substrate bearing capacity in situ is described. The device was used in various shallow water (&lt; 9 m) carbonate reef environments. Criteria for design and operation were based on ability to deliver controlled levels of stress to bearing plates of various sizes, operability underwater by scuba divers, transportability, and cost.
Determinations and Uses of Strain Distributions in Sand Samples
Authors: Wong RKS , Arthur JRF 
Published: February 2009

Abstract
The determination of strain distributions in dense sand samples is described in this paper. An estimate of all the possible errors during the measurement of strains is also made. It is shown that the much cheaper photographic method can replace radiography under plane strain conditions as a means of recording strains. Detailed strain distributions allow the evaluation of shear apparatus performance, and the strain distributions obtained in the directional shear cell are found to be as uniform as samples tested in the triaxial cell with “frictionless” ends. Using these strain distribution data, the inhomogeneous deformation response to uniform stresses of the most uniform sand samples is revealed and discussed.
Liquid Limit of Soil Mixtures
Authors: Sivapullaiah PV , Sridharan A 
Published: February 2009

Abstract
The liquid limit test is one of the most widely used tests in the soil engineering practice. Several properties, including mechanical properties (for example, compressive index), have correlations with the liquid limit. In this paper detailed investigations of the liquid limit of soil mixturs have been carried out using bentonite, kaolinite, sand (coarse grained, fine grained, rounded and angular shaped), and silts. Based on the results obtained, it has been shown that the liquid limits of soil mixtures are not governed by the linear law of mixtures. While the shape of the sand was not found to influence the liquid limit, the size of the sand particles had a definite influence. Liquid limit obtained by the cone method is lesser than the limit obtained by using the Casagrande apparatus. A good relationship exists between the results of these two methods. A procedure for obtaining the liquid limit of low plastic soil has been suggested.
Pore-Pressure Response of the Piezocone Penetrometer
Authors: Rad NS , Tumay MT 
Published: February 2009

Abstract
Cone penetrometers have been increasingly used in geotechnical investigations during the past several decades. The cone penetration test is recognized as a reliable, simple, fast, and economical in-situ testing technique. Implementation of pore-pressure transducers inside cone penetrometers to monitor the penetration pore pressure during a sounding has strongly increased their applicability and versatility. However, the accuracy of the recorded pore pressures and especially the effect of the degree of saturation of the pore pressure measuring system on the monitored values are debatable. This study is an attempt to provide a deeper insight into this matter.
Theoretical and experimental investigations were conducted. The theoretical work led to the derivation of an equation that may be used to estimate the period of time necessary to achieve an equilibrium inside the pore-pressure measuring system of a partially saturated piezocone. The experimental results revealed that (1) a fully saturated piezocone is capable of responding promptly and accurately to the generated pore pressures during a sounding and (2) the accuracy of the pore-pressure response of a partially saturated piezocone is affected by its degree of saturation as well as the hydraulic conductivity and the geometry of the piezometric element.
Sand Density Measurements for Laboratory Studies
Authors: Trautmann CH , Kulhawy FH , O'Rourke TD 
Published: February 2009

Abstract
A review of laboratory density measurement techniques suggests that the density pan and the density scoop constitute a useful and complementary pair of methods. Both are described in detail and analyzed with respect to bias and random error. Of the two techniques, the density pan is most useful in loose sand and has a coefficient of variation of about 1% for dry, medium-grained sand. The density scoop is most useful in medium to dense sands and also has a coefficient of variation of about 1%. Using these two techniques and a simplified statistical procedure described in this paper, an experimenter can design a program of measurements to measure the density of a given deposit with any desired level of confidence.