bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Viscous Fluids on Properties of Sand
Authors: Zeng X , Wu J , Young BA
Published: February 2009

The time scale for dynamic events differs from that for consolidation events if the same soil and pore fluid as in the prototype are used in a model test. In order to satisfy the scaling relationship for dynamic centrifuge tests, viscous fluids such as silicone oil or glycerin-water mixtures have been used as the pore fluid. The use of a pore fluid with higher viscosity will significantly reduce the permeability of a soil, making it possible to achieve the same time scale. However, the use of viscous fluids may also affect the mechanical properties of soils such as strength and stress-strain relationship. This paper presents results of permeability tests and triaxial tests on two types of sands over a range of void ratios. It is found that using a glycerin-water mixture as the pore fluid has little effect on the strength and stress-strain relationship of Ottawa sand No. 40. For tests with both silicon oil and glycerin-water mixture as permeants, coefficients of permeability are inversely proportional to the viscosity. However, at small hydraulic gradients, it was observed that the highly viscous fluids can cause clogging of flow in sand, especially for silicone oil in dense sand. It is recommended that when a viscous fluid is used in a centrifuge test, it is desirable to conduct a sequence of laboratory tests to make sure there is no unexpected influence on the properties of a soil.
Compaction Curves on Volume Basis
Authors: Prashanth JP , Sivapullaiah PV , Sridharan A
Published: February 2009

The compaction curves of soils are generally expressed in terms of dry density and water content. While this representation serves well to compare the efficiency of compaction of different soils whose specific gravities lie in a narrow range (2.6 to 2.7), it fails for materials of varying specific gravities. It has been shown that for fly ashes with a wide range of specific gravities the degree of compaction of different fly ashes cannot be compared from conventional compaction parameters. Compaction curves expressed on a volume basis, viz., volume of solids per unit volume of compacted sample or porosity or void ratio and volume of water per unit volume of solids, can better serve to explain the compaction. Further, it has been shown that for fly ashes of different specific gravities only compaction parameters expressed on a volume basis can be interrelated.
Ring Shrinkage Test for Expansive Clays: A Suggested Simple Test Method for Determining Vertical, Lateral, and Volumetric Shrinkage Potential
Authors: Hanafy EADE
Published: February 2009

The ring shrinkage test is proposed as a new soil testing method for expansive clays to describe quantitatively the soil shrinkage potential. The test provides direct measurements of the linear shrinkage in the form of vertical and lateral changes. In addition, the test provides an alternative test method for determining the shrinkage limit and volumetric shrinkage. The method requires undisturbed samples, and it utilizes the standard oedometer ring of consolidation testing equipment. Description of the proposed test method is presented including details of specimen preparation and data measurements.
Preparation Techniques for Oil-Sand Testing
Authors: Dusseault MB , Soderberg H , Sterne K
Published: February 2009

Evaluation of technologies for oil-sand mining and enhanced oil recovery in oil sands and other uncemented sandstone reservoirs requires high-quality undisturbed samples and special sampling, preparation, and testing techniques to minimize the effects of sample disturbance by expansion. This paper presents some methods developed for storage, preparation, and laboratory testing of the geomechanical properties of oil sands. These techniques have application to the handling of other earth materials that are difficult to prepare for testing.
Identification of Shales
Authors: Hopkins TC , Deen RC
Published: February 2009

Engineering tests were performed on 40 different types of shales. Both hard and soft shales, as well as shales having histories of embankment failures and shales having little known involvements, were tested. The suitability of ten different slake-durability test procedures was evaluated as a means of broadly characterizing the engineering performance of Kentucky shales. Two procedures devised during the study appeared to better characterize slake-durability properties than procedures previously proposed. Natural water contents and jar slake tests were performed to determine if such tests might provide a fairly rapid means of identifying troublesome shales. The natural water content of a shale was a strong indicator of the slake-durability properties. Swelling properties of ten shale types were examined. A good correlation was obtained between a newly devised slake-durability index and the water content of a shale after swelling was completed. When exposed to water, most of the shales exhibited high swell pressures.
Estimation of the Modulus of Elasticity of Cement Stabilized Materials
Authors: Kolias S , Williams RIT
Published: February 2009

A method of rapid estimation of the modulus of elasticity of cement stabilized materials from data that are usually available, without the need to resort to laboratory modulus determinations, is desirable especially for use in pavement analysis. This paper describes the derivation of a method for continuously graded materials, which is based on a single number grading index, that is, the gradation modulus, which can readily be calculated from the grading curve of the material to be stabilized. Another method derived empirically and based on the bulk density and optimum moisture content of the stabilized material is also presented. Predicting accuracy of the methods is compared with data available from the literature and is judged satisfactory for pavement analysis purposes.
Effects of Dust Suppressants on Tailing Sand Permeability
Authors: Scott JC
Published: February 2009

Permeability test results using tailing sand and six dust suppressants are presented. Dust suppressant dilution and application rates used were those recommended by the chemical manufacturers for tailing deposits. Each specimen was placed at a dry density of 15.6 kN/m3 (99.2 pcf) and a moisture content of 8% in standard U.S. Bureau of Reclamation (USBR) percolation cylinders. These initial conditions represented average values measured in tailing dam sand beaches.
The Theory of One-Dimensional Consolidation of Saturated Clays: III. Existing Testing Procedures and Analyses
Authors: Znidarcic D , Croce P , Pane V , Ko H-Y , Olsen HW , Schiffman RL
Published: February 2009

The successful calculation of the progress of consolidation requires that both the theory used to model the field problem and the material properties used by the theory must be appropriate and suitable. Thus the testing procedure must provide reliable and consistent information on the material behavior. Further, the test procedure must be accompanied by methods of analysis that will produce values of the material properties that are appropriate to the theory.

This paper presents a summary of the existing laboratory methods that are used to determine the consolidation properties of soils. Emphasis is placed on the analysis of the test data. It is shown that all the methods that are currently used contain inherent simplifying assumptions. These methods are restricted in their applicability to problems where linear or constant material properties or both are good approximations to real behavior.
The Centrifuge as a Research Tool
Authors: Cheney JA , Fragaszy RJ
Published: February 2009

The principal uses of the centrifuge in geotechnical research are discussed following a short historical review. The principle of centrifuge modeling is based upon the requirement of similarity by model and prototype. This requirement can be determined either by analysis of governing differential equations or by dimensional analysis and the theory of models. Verification of similarity may be established by direct comparison with full-scale objects (usually prohibitively expensive) or by comparison with model tests at other scales (modeling of models). Centrifuge tests can also provide data for verification of numerical models and for theorizing on the fundamental behavior of soil structures.
Drum Centrifuge for Geotechnical Research
Authors: Cheney JA , Fragaszy RJ , Schofield AN
Published: February 2009

The use of a drum centrifuge for geotechnical research is described. This type of centrifuge is distinguished by its ability to carry a payload around the entire circumference of a rotating drum. This allows the formation of “endless” slopes and gives the centrifuge a large capacity at very low cost. The design and construction of the centrifuge is described in detail. Also, the test procedures used to conduct slope stability experiments, including consolidation of a clay slurry, in-flight cutting of the slope, and both short- and long-term stability tests are discussed. Deviations from true similarity, between model and prototype are listed, including fluctuation in acceleration, variation in water content, and stress paths. Possible future uses of the drum centrifuge are presented.
Platform Orientation and Start-up Time During Centrifuge Testing
Authors: Bloomquist DG , Davidson JL , Townsend FC
Published: February 2009

Two techniques are introduced that improve the reliability of centrifuge testing of settling slurries. In the first, mechanical equipment modifications are described that allow a correct platform orientation to be achieved during flight. In the second, a simple mathematical equation is derived to account for the start-up period, during which the acceleration has not yet reached the final test level.
The Revised ASTM Standard on the Unified Classification System
Authors: Howard AK
Published: February 2009

ASTM Test Method for Classification of Soils for Engineering Purposes (D 2487) was significantly revised in 1983. The revisions require that soil is to be classified by using both a symbol and a name, and the group names were standardized. Organic silts and clays were redefined to recognize that organic soils occur that plot above the “A” line on the plasticity chart. More precise guidelines were established, particularly with regard to plasticity, so that only one particular classification will result. If boarderline classifications are used, the classification symbols are separated with a slash with the classification symbol indicated using the standard appearing first. Appendixes give example written descriptions, preparation of soil for testing, and guidelines for using the system for materials such as shale, mudstone, crushed rock, and slag
Development and Evaluation of Ultrasonic Piezoelectric Transducers for the Determination of Dynamic Young's Modulus of Triaxially Loaded Rock Cores
Authors: Howarth DF
Published: February 2009

Equipment has been developed that enables the rapid determination of dynamic Young's modulus of triaxially loaded rock cores. Measurement of dynamic modulus is based on a pulse propogation technique using piezoelectric transducers. A detailed description is given of the development of the equipment suitable for laboratory investigations. Details of a laboratory study investigating the variation between static and dynamic moduli of triaxially loaded rock cores are given.
A Scanning Device to Quantify Joint Surface Roughness
Authors: Lam TSK , Johnston IW
Published: February 2009

The shear strength characteristics of rock joints are highly dependent on the roughness of the joint surfaces. However, roughness is a relative term and current methods of describing roughness in quantitative terms are generally not suited to detailed analytical scrutiny. In connection with an investigation into the development of side shear resistance in rough rock socketed piles, a scanning device, which was automatic and free from operator subjectivity, was developed to provide detailed measurements of surface roughness of joint samples obtained in situ. The data collected were suitable for statistical analysis so that surface roughness could be uniquely quantified. The design and operation of the device is described, and an example of scanning is presented.
Resonant-Column Apparatus for Coarse-Grained Materials
Authors: Heiniger C , Studer JA
Published: February 2009

To investigate the low-strain dynamic properties of soils with grain size up to 25 mm (1 in.), a resonant column apparatus for specimens of 150 mm (6 in.) diameter and 450 mm (18 in.) height has been developed. Fine-grained materials can be tested using smaller specimens of at least 50 mm (2 in.) diameter. Compressive and torsional wave propagation at strains of the order of 10−4% and into the nonlinear range (up to approximately 5 × 10−2%) can be investigated at ambient air pressure up to 600 kPa (87 psi). Keeping the amplitude of excitation constant by means of an electronic feedback system, the specimen's resonant frequency and amplification can be found directly from the response curve by recording the amplitude ratio of accelerations at both ends of the specimen as a function of frequency. The equipment can be adapted to special research requirements or used to carry out routine measurements for scientific consulting.
Repeated Load Triaxial Testing of Frozen and Thawed Soils
Authors: Cole DM , Durell G , Chamberlain E
Published: February 2009

This paper describes the equipment and methodology used to determine the resilient properties of granular soils that exhibit thaw-weakening behavior. Such soils suffer a significant loss in stiffness as the result of freezing and thawing and subsequently experience an increase in stiffness during a recovery phase. The recovery phase results from gradual desaturation of the thawed soil and is characterized by an increase in the soil moisture tension level. We have developed a means to simulate this freeze-thaw-recovery process in the laboratory that calls for testing specimens several times at soil moisture tension levels corresponding to field observations.

We have designed test cells with removable bases to facilitate this sequential testing procedure. A given specimen remains on one cell base throughout the course of testing, thus avoiding excessive handling and allowing the material to remain in contact with a porous element built into the base. The porous element is part of a tensiometer system that continuously monitors the moisture tension level of the soil.

The cells are equipped with axial and radial displacement transducers and a load transducer, which, along with the other cell components, are assembled about each mounted specimen to be tested. All transducers are interchangeable between our larger and smaller triaxial cells. The cells receive 152.4-mm-diameter, 381-mm-long specimens and 50.8-mm-diameter, 127-mm-long specimens, respectively.
ASTM Geotextile Committee Testing Update
Authors: Suits LD , Carroll RG , Christopher BR
Published: February 2009

The use of geotextiles is a relatively new accepted concept in the field of geotechnical engineering. As a result there is a lack of standard procedures or test methods for evaluating the engineering properties or characteristics of geotextiles. ASTM Committee D-35 on Geotextiles and Related Products has evolved from two former subcommittees working jointly under two different Main Committees. This took place in the interest of accelerating the development of much needed test standards. The paper reviews the activities of Committee D-35 in the development of these standards. It also presents the authors' recommendations as to procedures to be followed until such time as these methods become accepted through ASTM. The basic procedures for the three standards that have been accepted and published as of the summer of 1985 are also presented.
Parameter Sensitivity of Hydraulic Conductivity Testing Procedure
Authors: Peirce JJ , Sallfors G , Peterson E
Published: February 2009

A methodology is presented that allows researchers to identify which parameters have the largest effect on key parameter(s), and thereby a priori direct investigations to concentrate on the most important area(s) of concern. Laboratory testing is often used in research to establish the effect of one or more parameters on one or more other parameters of concern. Because laboratory testing often is costly as well as time consuming, the number of tests in the laboratory necessarily must be limited. Therefore the effect of only a few parameters, sometimes only one, can be investigated. The choice of parameters to be studied is often made somewhat arbitrarily, and risks exist that the effect of an important parameter is overlooked.

The features of a ruggedness test are explained and its use is illustrated. A series of hydraulic conductivity tests are documented. Seven different parameters are varied in a total of eight tests to study their effects on the hydraulic conductivity. From the results it was possible to identify a select subset of parameters which have the greatest effect on the hydraulic conductivity: water content, lift thickness, and backpressure. Interaction between any two of these parameters, however, may produce confounding effects on the third. The method proved to be very effective and is suggested for application in other areas of investigation.
The Revised ASTM Standard on the Description and Identification of Soils (Visual-Manual Procedure)
Authors: Howard AK
Published: February 2009

ASTM Practice for Description and Identification of Soils (Visual-Manual Procedure) (D 2488) was significantly revised in 1984. Revisions were made to parallel the recent changes in ASTM Classification of Soils for Engineering Purposes (D 2487) and to reflect more of current practices used for visual-manual description and identification. Where possible, the number of terms for descriptive information (dry strength, moisture condition, and so forth) was reduced, and the criteria for deciding which term to use were made less subjective. Criteria for describing particle shape and for describing cementation of coarse-grained soils were added. Appendixes give example written descriptions, procedures for estimating particle size distribution, and guidelines for using the system for materials such as shale, mudstone, crushed rock, and slag.
Impact-Echo Response of Concrete Shafts
Authors: Lin Y , Sansalone M , Carino NJ
Published: February 2009

Numerical and experimental studies of the transient response of concrete shafts subjected to elastic impact were carried out using the finite element method and the impact-echo testing technique. Two- and three-dimensional finite element studies of concrete shafts were performed for: (a) solid shafts; (b) shafts containing cracks, voids, layers of low-quality concrete, and changes in cross section, such as bulges and necks; and (c) shafts in soil. These studies were carried out to gain an improved understanding of the impact response of concrete shafts containing flaws, problems for which there are currently no analytical solutions. It was also the intent of the numerical studies to determine whether information in addition to that obtained with existing nondestructive testing techniques could be obtained during impact testing of concrete shafts. Laboratory studies of solid concrete shafts were carried out to verify the finite element models. Subsequently, experimental studies were carried out on concrete shafts embedded in soil. These shafts contained flaws at known locations. The results of these studies show that additional information about the integrity of drilled shafts and piles can be obtained using impact techniques. The numerical studies also show that the finite element method is a powerful tool for studying the impact response of concrete foundation elements.
Hydrodynamic Aspects in the Rotating Clyinder Erosivity Test
Authors: Rohan K , Lefebvre G
Published: February 2009

A comparison of different experimental installations used to study clay erosivity is presented. Flow in a rotating cylinder used in geotechnical laboratories is studied in detail. Analysis of the shear stress is presented, and conclusions are drawn as to the limitations of the quantitative evaluations of the critical shear stress in the rotating cylinder test.
Simple Shear of an Undisturbed Soft Marine Clay in NGI and Torsional Shear Equipment
Authors: Talesnick M , Frydman S
Published: February 2009

A series of undrained, simple shear tests were performed on undisturbed, soft, marine clay from the continental slope of Israel in a direct simple shear device (NGI) and in a new torsional shear apparatus. The new apparatus is described, and the problematics of simple shear testing in both devices are discussed. Most previous torsional shear testing on clays reported in the literature has been performed on remolded specimens. In order to prepare specimens from undisturbed samples of the soft, marine clay, whose natural moisture content is close to the liquid limit, a special preparation technique was developed. A comparison of the stress-strain curves obtained in the two devices indicates higher stiffness and strength of the specimens tested in the torsional equipment; a similar observation has been reported in the literature from tests on sands and remolded clays. It is the authors' view that the main cause for the discrepancy is flexibility of the confining membrane in the NGI equipment. In view of the relevance of simple shear conditions to actual field problems, it appears important to further clarify this difference and to establish an accepted method for simple shear testing in the laboratory.
Uniformity Tests in Calibration Chamber Samples by the Thermal Probe Method
Authors: Bellotti R , Ghionna VN , Morabito P
Published: February 2009

The calibration of geotechnical instruments for in-situ tests, performed on sand samples reconstituted in huge calibration chambers (CC), requires the reproduction of large specimens at given relative densities with good repeatability and satisfactory homogeneity. A test method has been developed with the purpose of evaluating the relative density, DR, in different locations of the CC samples without removing sand.

The method is based on experimental correlations between the density and the thermal conductivity of dry sand. The thermal conductivity is determined by small thermal probes, 1 mm in diameter and 70 mm in length, placed in different locations inside the calibration chamber before the pluvial deposition of the specimen. The homogeneity of the specimen is assessed by the local values of DR. A calibration procedure of the thermal probe is proposed that takes into account the effects of stresses on the thermal conductivity of the sand. Examples of uniformity tests performed in ENEL-CRIS and ISMES calibration chambers are presented.
Influence of Voids on Density Measurements of Granular Materials Using Gamma Radiation Techniques
Authors: Tan S-A , Fwa T-F
Published: February 2009

The use of gamma radiation equipment for the nondestructive measurement of soil density originated nearly four decades ago. The typical procedure involves a careful calibration of the gamma radiation counts on specimens of known density of the same materials as those whose density are to be measured. This paper presents the results of laboratory gamma-ray density measurements on 100-mm-diameter specimens with an adapted twin-probe transmission-type density gage originally developed for field use. Primary factors affecting density calibration for soils include soil composition and soil porosity. To appreciate the soil composition factor, 100-mm-diameter specimens of solid materials similar to the soil minerals were tested, and from the data a linear ln (COUNT) versus DENSITY calibration line for solid materials was obtained. Next, aluminium cylindrical specimens with concentric holes of various diameters representing various porosities from 0 to 90% were tested. When compared to the solid material calibration line, it is clear that the bulk density calculated based on the gamma-ray path geometry gives the same calibration as the solid specimens. Subsequently, cylindrical specimens of dry sands and gravels were also made and tested. Results indicate that specimens of uniform densities and uniform void distributions must be used for calibration. Subsequently, using the calibration line obtained for solid homogeneous specimens, densities of porous soils measured by the gamma-ray device would be the bulk density of the materials confined in the path geometry of the gamma rays. Thus the gamma-ray apparatus can be a very useful tool for identifying nonuniformities due to void variation within the same specimen.
Resonant Column Tests on Partially Saturated Sands
Authors: Qian X , Gray DH , Woods RD
Published: February 2009

This paper describes the measurement of the influence of capillary effects on the dynamic shear modulus of partially saturated sands. A Hall-type resonant column apparatus was used to perform the experiments. The materials tested included natural angular and subrounded sands, angular and subrounded sands with specified artificial gradations, and uniform angular and subrounded sands with various minus No. 400 sieve size fractions.

Capillary stresses can significantly increase the shear modulus of unsaturated sands. Void ratio, confining pressure, degree of saturation, grain shape, and grain-size distribution are the primary factors affecting the shear modulus of partially saturated sands.
Laboratory Properties of a Soft Marine Clay Reinforced with Woven and Nonwoven Geotextiles
Authors: Indraratna B , Satkunaseelan KS , Rasul MG
Published: February 2009

This paper is concerned with the laboratory properties of a geotextile-reinforced compacted soft marine deposit with respect to its compaction, compressive strength, and time-dependent settlement characteristics. Two different geotextiles, namely, Polyfelt TS-500 (nonwoven) and Cardon SG PP 150 (woven) have been investigated. It was observed from the experimental study that a nonwoven geotextile contributes very differently as compared to a woven geotextile when placed within soft clay soils. This is because of the fact that the nonwoven Polyfelt fabric allows better drainage (dissipation of pore pressures) in comparison with the woven Cardon geotextile, particularly at high moisture contents. The compactibility of the reinforced sample is affected by the moisture content, number of fabric layers, and the type of geotextile. With the presence of geotextiles, the compressive strength of the soil is dictated not only by the internal mode of failure induced in the samples, but also by the spacing and the drainage capacity of the geotextile layers.
Computer-Aided Pressuremeter Tests
Authors: Law KT
Published: February 2009

A completely portable computer-controlled servo-mechanism designed for use with the Cambridge self-boring pressuremeter consists of a computer, a data acquisition system (DAS), and an electric-to-pneumatic (E/P) transducer. The computer obtains information on the current state of a test through the DAS and determines the next step in accordance with prescribed test conditions. An appropriate voltage is then sent to the E/P transducer, which regulates in proportion to the voltage received the pressure for expanding the pressuremeter. At present, four test conditions are programmed: a controlled stress increment test, a controlled strain rate test, a controlled strain test, and a cyclic test. Experience with different soils shows that the mechanism operates to design specifications.
Permeability Testing in the Triaxial Cell
Authors: Carpenter GW , Stephenson RW
Published: February 2009

It has been suggested that a triaxial shear test chamber can be used to measure the permeability of low permeability soils. To verify this, the influence of a number of test parameters on the measured coefficient of permeability was investigated. Results indicate such permeability tests should be performed on samples having a minimum diameter of 71.1 mm (2.8 in.) and a length to diameter ratio of 0.5 to 1.0. It was found that a permeant consisting of 1 g of magnesium sulfate heptahydrate (epsom salt) dissolved in 1 L of deaired, distilled water is adequate for general permeability testing. The triaxial, falling head permeability test should be conducted at a gradient that results in an applied effective stress at the outflow end of the sample less than the preconsolidation stress of the material. It was found that with very careful trimming, the influence of the smear zones created at the ends of the samples during the trimming process can be minimized.
Experimental Study of Rheological Properties of a Sand Using a Special Triaxial Apparatus
Authors: Bouvard D , Stutz P
Published: February 2009

A special triaxial apparatus allowing for a gammametric measurement of local density is used to study the influence of experimental conditions in triaxial tests. Compression tests performed along different stress paths and classical extension tests provide reliable results on the rheological behavior of sand up to large strains and permit characterization of the limit state of perfect plasticity.
Swelling Pressure of Clays
Authors: Sridharan A , Rao AS , Sivapullaiah PV
Published: February 2009

Experiments by three methods to determine the swelling pressure of clays showed that the conventional consolidation test gives an upper bound value, the method of equilibrium void ratios for various consolidation pressures gives the least value, and tests by the constant volume method give intermediate values. However there is no definite relationship between the three methods. The paper also shows that time effects involved in conducting the tests and the effect of stress path are both significant. Time versus swelling, and to a greater extent, time versus pressure relations can be represented by a rectangular hyperbola, which can be used to predict the ultimate swelling and the swelling pressure, respectively.

Tests with varying initial conditions of molding moisture content and density have exhibited a unique relationship between swelling pressure and the initial dry density for black cotton soil. This result is in line with the osmotic pressure theory. The molding water content has marginal effect on the swelling pressure.
The Application of Multivariate Statistics and Saturation Extract Data to Identify Dispersive Clay Soils
Authors: Craft D
Published: February 2009

Soils from a geotechnical project in Oklahoma may be classified as dispersive or nondispersive with a high degree of confidence by substituting selected pore-water data (weight percent H2O at saturation, saturation extract pH, log base 10 of the pore-water conductivity, and log base 10 of the pore-water sodium concentration) into derived discriminant classification functions. The discriminant functions were derived using discriminant analysis, a multivariate statistical classification technique, performed on a 28-sample data set. This statistical procedure was utilized after problems were noted with the currently accepted porewater chemical test for dispersion, suggested by Sherard et al. Suggestions for using the derived discriminant function as the basis of a simple chemical field test and precautions regarding data interpretation are presented.
Estimating Liquefaction Potential of Sands Using the Flat Plate Dilatometer
Authors: Robertson PK , Campanella RG
Published: February 2009

A new flat plate dilatometer test (DMT) based method for liquefaction assessment of sand is presented. Field and laboratory data from a site near Vancouver, British Columbia, Canada are presented to provide a preliminary evaluation of the proposed DMT based liquefaction assessment method.
Effect of Cementation on the Cone Penetration Resistance of Sand: A Model Study
Authors: Rad NS , Tumay MT
Published: February 2009

A laboratory study was conducted to investigate the effect of cementation on the cone penetration resistance of sand. A new apparatus to form homogeneous artificially cemented sand specimens as well as uncemented ones, and a miniature quasi-static cone penetrometer were developed. Artificially cemented specimens with 1 and 2% cement content and relative densities ranging from 18 to 80% were tested. The penetration resistance of the cemented specimens was compared with those of comparable uncemented specimens. The influence of cement content and relative density of the specimens on their quasi-static cone penetration resistance was studied. The results indicate that cementation has a pronounced effect on the penetration resistance of sand.
Triaxial Equipment for Permeability Testing with Hazardous and Toxic Permeants
Authors: Evans JC , Fang H-Y
Published: February 2009

The measurement of the hydraulic conductivity of finegrained soils utilizing hazardous and toxic permeants requires equipment speciffically designed and constructed for that purpose. Interaction between the pore fluids in the soils and the resulting soil response must be considered as well as the compatibility between the test equipment and the permeants. Further, a method of modeling the state of stress and permeation relative to field conditions must be incorporated in order to arrive at a system that can adequately determine the effects of hazardous and toxic permeants upon the hydraulic conductivity of fine-grained soils.

The testing system developed for hydraulic conductivity testing with hazardous and toxic permeants has three major components. These are the control panel, the permeability board, and the triaxial cell. The necessary strength and compatibility was accomplished through the optimum use of stainless steel and aluminum to provide adequate rigidity while providing the ultimate compatibility through the use of Teflon® at any points in which the permeameter is in contact with the permeant. Equipment design and fabrication considerations in their special applicability for testing of hazardous and toxic permeants are discussed in this paper.
Procedure for a Rod Shear Test
Authors: Felio GY , Briaud J-L
Published: February 2009

A laboratory instrument, called the rod shear device, was developed to measure the shear transfer characteristics of a model pile inserted into a clay sample. The apparatus was designed to accommodate soil samples recovered from field investigations without extruding the specimen from its sampling tube and thus avoiding disturbance caused by stress relief and handling. A rod shear testing procedure is recommended for monotonic and cyclic loading tests. Typical results are presented.
Preparation of Specimens of Noncohesive Material for Mercury Intrusion Porosimetry
Authors: Juang CH , Holtz RD
Published: February 2009

This technical note describes a technique for the preparation of test specimens of compacted noncohesive granular material for mercury intrusion porosimetry (MIP) tests without altering or destroying the soil fabric. The technique makes it possible to measure and determine pore-size distribution (PSD) of the noncohesive soils by a standard MIP test method (for example, ASTM Test Method for Determination of the Pore Volume Distribution of Soil and Rock by Mercury Intrusion Porosimetry [D 4404]).

The technique involves use of a powdered phenolic resin. First, dry sand was mixed with a small amount of powdered resin (0.5% of dry weight of the sand) before compaction. After compaction, the sample along with compaction mold was placed in the oven at 170°C for 1 h. The melted resin acts as a glue to bond the sand grains together. Then the sample was removed from the oven, and the MIP specimens were trimmed from the resin-bonded sample. The results of repeated MIP tests on multiple specimens trimmed from resin-bonded compacted samples were very reproducible, which indicates that the proposed technique is a satisfactory way of preparing a noncohesive specimen for MIP tests.
Liquid Limit of Montmorillonite Soils
Authors: Sridharan A , Rao SM , Murthy NS
Published: February 2009

The present work investigates the influence of compositional factors on the liquid limit of montmorillonite soils. The results showed that the percent clay fraction and surface area values did not relate with the liquid limit of the soils; the latter, however, were essentially controlled by the diffuse double layer thickness. Examination of the relations between compositional factors that affect the double layer thickness and liquid limit showed that the latter did not have a significant bearing with cation exchange capacity, while a near perfect correlation was obtained with the amount of exchangeable sodium ions present. Such a dependence resulted because of the greater ease of dissociation of adsorbed sodium ions from the clay surface in presence of water and subsequent contribution to the double layer thickness; the other exchangeable cations, namely, calcium, magnesium, and potassium, were strongly adsorbed by the clay surface and did not contribute appreciably to the double layer thickness.
A Rapid Method to Identify Clay Type in Soils By the Free-Swell Technique
Authors: Sridharan A , Rao SM , Murthy NS
Published: February 2009

This paper reports a rapid method to identify the presence of nonswelling clay, swelling clay, or a mixture of the two types of clays in a soil from the sediment volumes occupied by 10 g of dry soil in 100 mL of water and carbon tetrachloride, respectively, under no external constraint. Soils that occupy a sediment volume of < 1.50 m3/Mg in water and 1.10 to 3.00 m3/Mg in carbon tetrachloride contain nonswelling clay. Soils that occupy sediment volume of ≤ 1.10 m3/Mg in carbon tetrachloride and a volume ≥ 1.50 m3/Mg in water contain swelling clay. Soils that occupy sediment volumes > 1.10 m3/Mg in carbon tetrachloride and volumes ≥ 1.50 m3/Mg in water contain both nonswelling and swelling clays. The results agree well with X-ray diffraction and infrared analysis.

In the latter part of the work, the limitations in the existing definition of the free-swell index of soils is brought out. The present definition gives a negative free-swell value for soils containing nonswelling clay and a reduced value for soils containing a mixture of nonswelling and swelling clays. The free-swell index of soils is defined as the sediment volume occupied by 10 g of dry soil in 100 mL of water under no external constraint and expressed in units of m3/Mg. Further, the sediment volume of a soil (10 g) in a nonpolar solvent, is utilized to give information on the clay type present in the soil, namely, nonswelling, swelling, or a combination of both. A classification for identifying a soil's expansivity based on the new definition of the free-swell index and the clay mineralogical composition of the soils is given.
Cyclic Simple Shear Testing of Granular Materials
Authors: Shaw P , Brown SF
Published: February 2009

Developments to a pneumatically operated simple shear apparatus for dry granular materials allowing application of cyclic shear and normal stresses are described. Boundary transducers were of only limited success for stress measurement so a prediction method for complete description of the stress state was used. Tests on uniform crushed limestone of 1.5- and 3-mm nominal sizes showed that increased volumetric strains were developed under cyclic normal stress and bidirectional shearing. Shear strains were not much influenced by cyclic application of the normal stress.
A Monte Carlo Investigation of a Proposed Screen for NX-Borehole Jack Data
Authors: Axelrod MC , Verrill SP , Patrick WC , Yow JL
Published: February 2009

Heuze has submitted a draft standard guide to the ASTM Subcommittee D18.12 on Rocks and Soils for using the NX-borehole (“Goodman”) jack and calculating the in-situ deformation modulus of rock masses. One aspect of the proposed standard is a “data screen” based on a full platen seating criterion. This article describes a computer simulation study that was performed to test the effect of the screen on the modulus estimate. The study demonstrates that the screen can actually degrade the quality of the estimate. It is concluded that the section of the proposed standard guide that deals with the screening of data should not be adopted.
Compressibility Properties of a Horticultural Peat
Authors: Morin P
Published: February 2009

The compressibility of a typical horticultural peat has been studied in the laboratory. Compressibility is an important factor in the processing of this material since volume governs the cost of shipping. The final reconstituted volume and the appearance of the peat after shipping must also be taken into account for marketing. Compression tests have been carried out on a horticultural peat from Newfoundland. Simple equations relating initial water content, relative volume change, and vertical applied pressure are proposed. A fluff factor has been defined, and it was found to decrease with the maximum applied pressure. Finally the results obtained in the laboratory are applied to storage and processing examples that are encountered in the horticultural peat industry.
The Measurement of Gas Bubble Size Distributions in a Three Phase Laboratory Gassy Soil
Authors: Gardner TN , Goringe MJ
Published: February 2009

The technique developed can be used to measure the total void, gas void, or particle size distribution in both gassy and saturated sediments provided the void spaces, or particles, can be approximated to spheres. Here the technique is demonstrated for measuring gas bubble size distribution in a reconstituted estuarine silty clay, which has been impregnated with methane gas using the method described by Nagaswaran. The process involves specimen preparation of a resin impregnated specimen to provide images using a scanning electron microscope (SEM). An average planar size distribution is obtained from the SEM images by computerized measurement of pixels on a monitor distinguished by luminance intensity phasing. Conversion from the planar to a spherical size distribution is carried out by a statistical method of probability. Results are presented that illustrate the consistency and accuracy of the measurement technique as a whole. Observations are made regarding the structure of the laboratory gassy soil which may be relevant to an in-situ sea bed gassy soil.
Assessment of the Unconfined Compressive Strength of a Lime Stabilized Soil by an Abrasion Test
Authors: Arabi M , Delpak R , Wild S
Published: February 2009

Stabilization by lime, which is frequently carried out to improve the mechanical properties of soils, results from the formation and development of cementitious calcium silicate aluminate hydrate gel. The gel produces interlocking and bonding of the soil particles, hence increasing the strength and abrasion resistance. The proposed method to assess the compressive strength of the existing structure of lime stabilized soil using a simple mechanical abrasion technique, provides an alternative means by which the strength characteristics can be assessed. The advantages of employing the abrasion method are (1) the relative ease of specimen collection and preparation as the test is not particularly sensitive to specimen size and shape and (2) the ease of application to existing structures as large-scale mechanical testing equipment would not be required once a calibration chart has been established, and testing could be carried out on site.
Removal of Cementation Bonds in Stressed Overconsolidated Clays
Authors: Griffiths FJ , Joshi RC , Nagaraj TS
Published: February 2009

Soils develop cementation during and after formation because of the effects of stress, time, and environment. The effects of cement removal on the change of state of soil under stress are discussed in this paper. The change in the state of stiff, overconsolidated, cemented clay under stress is reflected by void ratio change when the cementation bonds are removed. The observed increases in void ratio have been attributed to the latent physico-chemical behavior of the clay. The consolidation process is restrained during both deposition and subsequent stress history once clays are cemented. Upon further loading, clays with cement bonds removed follow the e-log σ paths predicted for the uncemented state of the same soil both for normally and overconsolidated stress conditions.
Effects of Borehole Fluid on Standard Penetration Test Results
Authors: Seed RB , Harder LF , Youd TL
Published: February 2009

The standard penetration test (SPT) represents the most widely used in-situ test method for evaluating the liquefaction resistance of saturated soils. Significant progress has been made in recent years in developing correlations between SPT results obtained using different test procedures and equipment in order to develop a higher degree of standardization for SPT testing. One of the heretofore unresolved factors affecting SPT results is the effect of borehole fluid type (for example, water or drilling mud). This paper presents a study in which field data were obtained from SPT performed in adjacent boreholes, some filled with water and others filled with drilling mud, at four different sites in order to investigate this effect. A total of 213 SPT were considered: 147 SPT in mud-filled boreholes and 66 SPT in water-filled boreholes. Borehole fluid type (drilling mud versus water) was found to have no significant effect on STP resistances measured so long as careful and appropriate drilling and sampling procedures are employed.
Automatic Volume Change and Pressure Measurement Devices for Triaxial Testing of Soils
Authors: Lade PV
Published: February 2009

Desirable requirements for volume capacity and precision of volume change devices for triaxial testing are studied, and operational requirements for devices suitable for automatic datalogging are reviewed. Two devices that fulfill these requirements have been constructed by the writer by combining existing design principles. One device consists of a buret system with differential pressure measurements, and the other device operates on the principle of a double acting piston in which rolling diaphragms and a displacement transducer are the main components. In addition to their ability to measure volume changes, each device is outfitted with a pressure transducer and valves to provide all necessary means for performance and measurements required for (CD) and (CU) tests.
A New Simple Shear Apparatus
Authors: Budhu M
Published: February 2009

A new simple shear device capable of measuring a complete set of stresses during simple shear deformation is described. This simple shear device tests a cuboidal specimen whose lateral sides are surrounded by a rubber membrane reinforced by a stack of Teflon® coated aluminum plates. One of the aluminum plates is used as a transducer to determine the lateral stresses on planes normal and parallel to the direction of shearing. A load cell located around the middle of the top boundary provides data to deduce the normal and shear stresses as well as the pore-water pressures.

A sample set of results are presented to illustrate some of the advantages of this new simple shear device. The advantages include the ease of specimen preparation, the determination of the stress invariants, the pore-water pressures at the center of the sample, and the rotation of the principal axes of strain and stresses on a routine basis.
Introduction to a New Apparatus for Hydraulic Fracturing Tests
Authors: Sun Y , Ting C
Published: February 2009

A new apparatus for hydraulic fracturing tests, on which the seepage and force boundary conditions can be controlled strictly, is briefly introduced here. Some test results obtained by using this apparatus are presented as an example. These results were compared with theoretical results obtained from rigorous mechanical analysis to illustrate the advantage of this apparatus.
Prevention of Sample Deterioration
Authors: Brown PT , Chow JC-P
Published: February 2009

A series of unconsolidated undrained triaxial compression tests was carried out on specimens of reconstituted kaolin to determine the effects on modulus and strength of two different methods of sample storage after unloading. These results are compared with the values obtained when no unloading occurs, and when unloading is followed immediately by testing. It is seen that use of a simple sample compressor to restore the in-situ vertical effective stress in the specimen is very successful in reducing the deterioration of samples between unloading and testing.