bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Back Pressure on Geotextile Transmissivity Tests
Authors: Huang A-B , Holtz RD , Wilcox AM 
Published: February 2009

Abstract
To evaluate the effects of back pressure on the measurements of geotextile in-plane transmissivity, a new test device has been developed. A series of transmissivity tests were performed under back pressures ranging from 6.9 to 414 kPa. Results show that the influence of back pressure is significantly less than that caused by the variability among different specimens. However, to obtain repeatable results and to conduct the tests efficiently, it is strongly recommended using deaired water and to flush the specimen before testing.
Simulation of Climatic Conditions in Centrifuge Model Tests
Authors: Craig WH , Bujang BKH , Merrifield CM 
Published: February 2009

Abstract
A review is presented of the need for simulation of effects associated with tide, rainfall, temperature variations, etc., in geotechnical centrifuge models. Interest in the overall theme was generated by a perceived need to model rainfall in long-term testing of models of an embankment which was otherwise found to dry out. The system used to overcome this particular problem is outlined, and results are presented. Experience of the authors and others in the wider field is summarized.
A Clay Calibration Chamber for Testing Field Devices
Authors: Anderson WF , Pyrah IC , Fryer SJ 
Published: February 2009

Abstract
This paper describes the design of a calibration chamber suitable for the preparation of uniform clay beds in which the performance of full-size field test devices may be studied. Details are given of the clay bed preparation procedure by which clay slurry is initially consolidated under K0 conditions and then further conso using equal or unequal horizontal and vertical stresses. Field equipment may be tested in the clay bed, which is maintained under known horizontal and vertical boundary stresses during the test. Self-boring pressuremeter tests have been successfully carried out in the clay bed.
Clay-on-Steel Ring Shear Tests and Their Implications for Displacement Piles
Authors: Tika-Vassilikos T 
Published: February 2009

Abstract
This paper presents results from ring shear tests involving shearing of clay against steel interfaces. The effect of rate of shearing on the shear resistance between the soil and steel at large displacements was examined. It is shown that the rate of shearing has a significant effect on the shear resistance between soil and steel. The implications of the results for the behavior of displacement piles are discussed.
Total Stress Probe Determination of Clay Slurry Density
Authors: Tan S-A , Liang K-M , Tan T-S , Karunaratne G-P 
Published: February 2009

Abstract
The progress of sedimentation, self-weight consolidation, and gain in surface strength of a hydraulic clay fill were observed by monitoring the density improvement of the clay slurry with time. A practical method of measuring the in situ slurry density profile with depth is to employ a submersible gamma-source, backscattertype nuclear density gauge. A slurry consolidation test in the laboratory has demonstrated that above 1.5 times the liquid limit, the horizontal and vertical total stresses are equal. Hence, from the horizontal total stress measurements with a vertical probe, the in situ vertical total stress profile of the slurry can be obtained. In principle, the integration of the density profile with depth gives the vertical total stress profile. Therefore, an estimate of the density can be made from the gradient of the vertical total stress with depth. Comparisons of field measurements of the total stress profile of a clay slurry in a reclamation project using the total stress probe and the density profile by the nuclear density gauge demonstrates this principle, thus confirming that the total stress probe with appropriate data interpretation can be used to measure the density of an in situ clay slurry around its surface.
Total Suction of Artificial Mixtures of Soil Compacted at Optimum Water Content
Authors: Acar YB , Nyeretse P 
Published: February 2009

AbstractThe effect of soil composition on total suction is investigated. Thermocouple psychrometers are used to measure total suction of compacted specimens of artificial soil mixtures prepared using kaolinite, sodium montmorillonite, and a fine sand. Specimens are compacted in a Harvard miniature compaction mold at the optimum water content. The measured total suction is related to fine fraction and activity of the soil mixtures. The total suction is also compared with the swelling potential. A classification system is presented.
Effect of Clod Size on Hydraulic Conductivity of Compacted Clay
Authors: Houston SL , Randeni JS 
Published: February 2009

Abstract
A study has been conducted to identify the causes for field-measured values of hydraulic conductivity of clay liners being typically two orders of magnitude greater than laboratory-measured values. It has been found through laboratory testing on large specimens that the size and gradation of clods and clumps of clay, prior to compaction, can significantly affect the measured hydraulic conductivity.
The results of this study are compared to existing studies on the effect of clods on hydraulic conductivity, and general agreement is found. It is concluded that, for clod sizes and gradations likely to occur in field compaction of clay liners, that differences in clod gradation and size between lab and field conditions can essentially account for the observed roughly two orders of magnitude discrepancy between lab and field-measured conductivities.
Revised laboratory testing procedures for both the before-liner construction and after-liner construction cases are recommended. The revised laboratory testing procedures are designed to correct the deficiencies in conventional lab testing and to produce unbiased estimates of field hydraulic conductivity values.
Properties of Some Kaolin-Based Model Clay Soils
Authors: Rossato G , Ninis NL , Jardine RJ 
Published: February 2009

Abstract
Kaolin has been widely used both in fundamental studies of soil behavior and in physical model tests. However, the properties of pure kaolin are somewhat atypical of natural clay soils. In the first part of this paper we compare the mechanical properties of sedimented kaolin to median trends established from tests on natural clays and argue that artificial soils incorporating a substantial granular fraction reflect more closely the behavior of “destructured” real clays. In the second part we report a laboratory investigation of one particular mixture and describe the stress-strain behavior and strength properties observed in a series of K0 consolidated triaxial tests in which local strain instrumentation was used to better define the stiffness characteristics at small strains.
Maximum Dry Density of Cohesionless Soils by Pluviation and by ASTM D 4253-83: A Comparative Study
Authors: Lo Presti DCF , Pedroni S , Crippa V 
Published: February 2009

Abstract
Maximum dry densities of a variety of granular soils, ranging from silty sand to sandy gravel (Dmax = 9.5 mm), were determined by ASTM Test Methods for Maximum Index Density of Soils Using a Vibrating Table (D 4253-83) and by pluviation. The effects of various test conditions during pluviation were also investigated. The pluviation method offers several advantages compared to that of the ASTM method: higher dry density, no particle crushing, less effect of segregation, and better repeatability. In addition, the pluviation method can be performed with greater facility in less time.
Measurements of Coupled Normal Deformation, Permeability, and Heat Transfer in Rock Joints Using a Triaxial Test Facility
Authors: Zhao J 
Published: February 2009

Abstract
A description is presented of a rock-mechanics triaxial test facility capable of coupled testing of medium-sized cylindrical rock specimens at axial loads to 2.67 MN, confining pressures to 140 MPa, pore pressures to 105 MPa, and specimen temperature to 400°C. The test cell of the system is modified to carry out tests on fluid mass and heat transfer through rock joints/fractures and thermomechanical deformation of joints/fractures. Details of test procedures and techniques for conducting the coupled hydro-thermo-mechanical tests are described. Data on both natural joints and artificially induced extension fractures in the Carnmenellis granite are presented and discussed in order to illustrate the multifunctional capability of the testing system to cover the requirement for further understanding of rock joint/fracture and rock masses.
The study showed that joint/fracture permeability and mechanical aperture decrease with increasing effective normal stress. The relationship between the changes of mechanical aperture and permeability is influenced mainly by discontinuity surface characteristics. The permeability decreases with increasing temperature while measured mechanical aperture increases. Heat transfer coefficient measured during hydro-thermo-mechanical tests varies from 300 to 1200 W/m2-°C and is affected by flow velocity, temperature, and joint/fracture surface properties.
Temperature Dependence of Soil Water Potential
Authors: Mohamed A-MO , Yong RN , Cheung SCH 
Published: February 2009

Abstract
To understand the process of coupled heat and water transport, the relationship between temperature and soil water potential must be known. Two clays, Avonlea bentonite and Lake Agassiz clay, are being considered as the clay-based sealing materials for the Canadian nuclear fuel waste disposal vault. Avonlea bentonite is distinguished from Lake Agassiz clay by its high sealing potential in water. A series of experiments was performed in which the two clays were mixed with equal amounts of sand and were compacted to a dry density of 1.67 Mg/m3 under various moisture contents and temperatures. A psychrometer was placed within the compacted clay-sand to measure the soil water potential based on the electromotive force measured by the psychrometer. The results indicate that the soil water potential at a particular temperature is higher for both clay-sand mixtures than predicted by the change in the surface tension of water; this effect is much more prominent in the Avonlea bentonite and at low moisture contents. The paper presents empirical equations relating the soil water potential with the moisture content and temperature of the two clay-sand mixtures.
A New Method to Measure the Effective Porosity of Clays
Authors: Meegoda NJ , Gunasekera SD 
Published: February 2009

Abstract
The effective porosity is a required parameter for the mass flow rate calculations in groundwater hydrogeology. It is also a useful parameter in geotechnical engineering. In this paper, a methodology based on the tracer analysis technique is proposed to measure the effective porosity of clays. A test apparatus was developed and operational conditions were optimized to measure the effective porosity in the laboratory. Then the effective porosity of three clays under different chemical environments was measured. The measured effective porosity values showed that there is no unique effective porosity value for a given clay when tested under different chemical environments. The ratio of effective to total porosity values for silty and low plastic clays decreased while those for high plastic clay increased with the increase in degree of contamination.
Dispersive Behavior of Nonswelling Clays
Authors: Sridharan A , Rao SM , Dwarkanath HN 
Published: February 2009

AbstractThis paper examines the possible factors that contribute to the dispersive behavior of compacted nonswelling clays and proposes the use of a synthetic organic stabilizing agent to reduce the dispersive tendency of such soils. Results of chemical tests on saturation extracts of the clays tested failed to identify them as piping susceptible. However, pinhole tests on statically compacted specimens showed the materials to be intermediate (ND3, slightly to moderately dispersive clays that slowly erode under 180 or 380 mm head) to completely dispersive (D1 dispersive clays that fail rapidly under 50-mm head). Use of a concentrated salt solution (2N CaCl2) and a solvent with lower dielectric constant (methanol, dielectric constant = 32.6) did not reduce the dispersive tendency of the compacted kaolinite in the pinhole test (diameter of hole = 1 mm), suggesting that deflocculation triggered by diffuse double layer repulsion does not contribute significantly to the dispersive tendency of nonswelling clays.Pinhole tests conducted with variously saturated (33 to 84%), compacted kaolinite specimens (γd = 1.28 Mg/m3 in all instances) suggested that compression of entrapped air in the voids by capillary absorption of water is not the primary factor causing dispersion of nonswelling clays.Experimental results showed that pinhole test classification of statically compacted kaolinite changes from D1 (dispersive) to ND3 (intermediate) on reducing the remolding water content from wet of optimum (w = 34%) to a dry of optimum (w = 27%) value. The differences in structure of the compacted clay due to differences in molding water content are considered responsible for the higher erosion resistance of the compacted kaolinite on lowering the molding water content. Subsequent lowering of water content below 27% has no further influence on the pinhole test classification of the compacted clay.The use of a synthetic long chain organic polymer, poly vinyl alcohol (PVA), in improving the resistance of compacted nonswelling soils was tested. The addition of 1% PVA solution to kaolinite transforms the nonswelling clay from dispersive D1 to the dispersive D1/D2 category suggesting that the long chain organic polymer can improve the dispersion tendency of nonswelling clays to a slight extent.
On the Measurement of Critical State Parameters of Dense Granular Soils
Authors: Chu J , Lo S-CR 
Published: February 2009

Abstract
Existing test methods for measuring the critical state parameters of granular soils are reviewed and critically evaluated. It is concluded that, in triaxial testing of dense sand, significant nonhomogeneous deformation will develop prior to approaching a critical state. Hence, the critical state parameters so measured are questionable. A new test method, referred to as post-failure undrained testing, is presented. The proposed method is simple, but can bring a dense granular sand to a critical state without development of noticeable nonhomogeneous deformation. The critical state parameters so measured with dense specimens agree well with those measured with loose specimens. This is consistent with the postulate that the critical state surface is unique.
A Low-Compliance Bi-Directional Cyclic Simple Shear Apparatus
Authors: Boulanger RW , Chan CK , Seed HB , Seed RB , Sousa JB 
Published: February 2009

Abstract
A new simple shear apparatus is described which can apply bi-directional simple shear cyclic and monotonic loading. Cylindrical specimens are placed in a pressure chamber so that confining pressure and back pressure can be applied. Bi-directional shear loads are applied to the specimen's base, which is mounted on a series of two horizontal rolling tables which can be independently loaded in two orthogonal directions while preventing cap and base platen “rocking.” A computer-automated feedback-loop-controlled pneumatic servovalve system provides excellent control of loads and displacements. Displacement control during cyclic tests on softening specimens is improved by the inclusion of a parallel stiffness. Procedures and test results are presented for three different undrained cyclic simple shear loading conditions and for a strain-controlled monotonic loading condition.
Filtration Opening Size of Geotextiles by Hydrodynamic Sieving
Authors: Mlynarek J , Lafleur J , Rollin A , Lombard G 
Published: February 2009

Abstract
The latest development on the hydrodynamic sieving technique (HST) using glass beads to determine the filtration opening size (FOS) of geotextiles is presented. The FOS value is defined as the 95% (by mass) diameter of the glass beads which have passed through the geotextile under the hydrodynamic sieving action. The data of an experimental program to verify the repeatability and reproducibility are reported and discussed. The technique was found to be simple and repeatable for all types of geotextiles. The FOS of geotextiles measured by the HST is related to the geotextiles' general parameters such as their mass per unit area and thickness. The FOS value can be roughly estimated from simple knowledge of these parameters using the relationship established for the type of product.
A New Model of Shear Strength of Simulated Rock Joints
Authors: Juang CH , Lee D-H , Chang C-I 
Published: February 2009

Abstract
This paper documents a new model of shear strength of simulated rock joints based on roughness characteristics of the joints. The new model incorporates the concept of shear strength of rock joints proposed by Peek (1981) and Saeb (1990). The model is verified by results of an experimental program involving direct shear tests and the measurement of roughness profiles of simulated joints. The paper concludes that the new model is valid, based on experimental results, for simulated joints made of plaster. More study on other joints made of different materials and on real rock joints is needed to verify the general validity of the model.
Rockfill Placement and Compaction Guidelines
Authors: Breitenbach AJ 
Published: February 2009

Abstract
The purpose of this article is to establish general guidelines for rockfill placement and compaction procedures. The guidelines are based on experience gained from the design and construction of several large rockfill tailing dams in the western United States. Valuable rockfill information was obtained from construction test fills using test procedures similar to those developed by the Corps of Engineers in the 1960s and modified for modern-day compaction equipment. The rockfill guidelines establish basic procedures that can be readily adapted to site-specific conditions.
Compatibility of Compacted Soils with Municipal Waste Combustion Ash Leachates
Authors: Sai JO , Anderson DC , Sullivan BP 
Published: February 2009

Abstract
Hydraulic conductivity values for three compacted soils were used as indices of compatibility of the soils with two municipal waste combustion (MWC) ash leachates. Specimens of the three soils were compacted to 90% of proctor compaction (ASTM D 693) in double-ring permeameters and permeated first with water (0.005 N CaSO4) and then with MWC ash leachate. The hydraulic conductivity values of the soils did not change significantly after passage of more than two pore volumes of either MWC ash leachate. All three compacted soils were compatible with both MWC ash leachates.
δ-t/δ Method for the Determination of Coefficient of Consolidation
Authors: Sridharan A , Prakash K 
Published: February 2009

Abstract
Terzaghi's theoretical time factor, degree of consolidation relationship when plotted as U versus T/U, enables one to get a convenient form of curve-fitting method to determine the coefficient of consolidation. The time corresponding to 90% consolidation can be obtained more precisely from the proposed δ-t/δ method than the δ−√t method. The present article deals with the theoretical and practical aspects of results obtained from δ-√tand δ-t/δ representations.
Round One—Longitudinal and Transverse Pulse Velocities, Unconfined Compressive Strength, Uniaxial Elastic Modulus, and Splitting Tensile Strength
Authors: Pincus HJ 
Published: February 2009

Abstract
An interlaboratory study has been conducted using four ASTM rock-property test methods (longitudinal and transverse pulse velocity, indirect tensile strength, unconfined compressive strength, and uniaxial elastic modulus) on four types of intact rock (Barre Granite, Berea Sandstone, Salem Limestone, and Tennessee Marble). There were five replications per test per rock type. The rock testing was preceded by pilot testing on aluminum alloy 6061 T6 test specimens of four sizes, using the two nondestructive ASTM test methods (pulse velocity and elastic modulus) with three replications. The number of laboratories producing data for this report ranged from six to eight.
The test results for aluminum are generally more precise than those for rock. The rock-property tests with the largest and smallest precision are longitudinal pulse velocity and indirect tensile strength, respectively. The rock types yielding the greatest and least precise test results are Barre Granite and Berea Sandstone, respectively.
Proposed precision statements are presented for the four ASTM rock-property test methods used in this study.
An Initial Study of Surface Wave Inversion Using Artificial Neural Networks
Authors: Meier RW , Rix GJ 
Published: February 2009

Abstract
An artificial neural network is proposed as an expeditious alternative to the trial-and-error and least-squares surface wave inversion techniques that are currently available. To use an artificial neural network for surface wave inversion, synthetic dispersion curves are calculated for representative shear wave velocity profiles using a theoretical wave propagation algorithm. An artificial neural network is then “taught” to map these dispersion curves back into their respective shear wave velocity profiles. Once the network has been successfully trained on these synthetic dispersion curves, experimental dispersion curves can be inverted by passing them through the neural network. Because the neural network requires only a single forward pass of the data, it performs inversions much more quickly than iterative procedures.
To determine the feasibility of using an artificial neural network for surface wave inversion, a two-dimensional wave-propagation algorithm was used to create synthetic dispersion curves for 99 000 randomly generated, two-layer velocity profiles. A backpropagation neural network was then trained to associate the synthetic dispersion curves with their respective velocity profiles. The trained network was evaluated using synthetic dispersion curves for another 1000 randomly generated velocity profiles as surrogate experimental curves.
Compactor Force and Energy Measurements
Authors: Filz GM , Brandon TL 
Published: February 2009

AbstractTwo hand-operated compactors (a vibrating plate compactor and a rammer compactor) were instrumented to measure the dynamic contact force and energy transfer between compactor and soil. The instrumentation schemes, data acquisition techniques, and data reduction methods are described. The instrumented compactors were operated on two soils: a moist, silty sand and a dry, clean fine sand. The measured forces and energies are presented and compared to the manufacturer's ratings.
Determination of Swell Potential of Al-Qatif Clay
Authors: Abduljauwad SN , Al-Sulaimani GJ 
Published: February 2009

Abstract
Knowledge of the swell potential of expansive soil at the outset of an investigation can be helpful in avoiding possible damage to the structure. A review is presented of several methods that have been proposed to identify swell potential and test techniques, which are used to quantify the amount of swell. A site investigation was conducted to obtain hand-carved block specimens from a fresh excavation site near Al-Qatif, Eastern Province of Saudi Arabia. Laboratory tests were used to determine geotechnical and physicochemical properties and mineralogical composition. The results of a range of laboratory tests, including oedometer types, filter paper, triaxial, and new stainless steel tank apparatus, showed the problems associated with investigating swell behavior of soils. A field swelling test was conducted, and results are compared with laboratory tests to establish guidelines for estimation of swell potential.