bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Dual Interface Apparatus for Testing Unrestricted Friction of Soil Along Solid Surfaces
Authors: Paikowsky SG , Player CM , Connors PJ 
Published: February 2009

Abstract
A dual interface shear apparatus (simple or direct) was developed to evaluate the distribution and magnitude of friction between granular materials and solid inextensible surfaces. Ideal and natural granular materials were sheared along controlled and random solid surface geometries. The test results were evaluated through a model describing the interface friction mechanism based on a micromechanical approach. The influence of boundary conditions and interfacial shear modes was examined and compared to the results obtained in a modified direct shear box.
The test results show that the grain shape and the surface roughness, quantified with respect to the grain size, are the primary parameters controlling the interfacial shear strength at a given normal stress level. Three zones of normalized roughness associated with different shear strength levels were identified. These zones can be categorized into two possible shear mechanisms: interfacial and internal. The use of a small-size direct shear box (modified) to evaluate interfacial friction seems markedly influenced by the boundary conditions. The resulting interface friction angles exceed those that would develop along an unrestricted interface of soil and a solid surface, especially when shear takes place along the solid surface (e.g., smooth and intermediate normalized roughness). Erratum to this paper appears in 18(4).
The Rapid Determination of the Moisture-Retention Characteristics of Soil
Authors: Fourie AB , Papageorgiou G , Blight GE 
Published: February 2009

Abstract
A modified technique is described for determining the water-retention curve of a soil. The new technique allows the definition of a moisture-retention curve (typically six to seven data points) much more rapidly than is possible with conventional techniques such as the pressure plate apparatus. The full curve may be determined in four to six days compared with two to three weeks previously. Results are presented for three different soils. For one soil (a fly ash), comparative testing using the new technique and a conventional method shows good agreement. An added advantage of the new technique is that overall volume change of the soil specimen may be measured and not merely inferred from measurements of moisture outflow. Greater accuracy in determining the moisture-retention curve was thus obtained.
Geotechnical Properties of the Maryland-Sanders Lunar Simulant
Authors: Goodings DJ , Lin CP 
Published: February 2009

Abstract
Densely compacted Maryland-Sanders ground basalt was examined for the similarity of its geotechnical properties to those estimated for lunar regolith. Minimum and maximum densities fell within the upper range of those calculated to exist on the moon. Cone penetration resistances measured on specimens compressed to 80 and 100% relative densities bracket those reported for stress equivalent depths on the moon. The results of direct shear tests on specimens compressed to 100% relative density with normal stresses varying from 21 to 100 kN/m2 gave straight-line strength envelopes of c = 14 kN/m2 and φ = 39° for peak strength and c = 9 kN/m2 and φ = 37° for postpeak strength. Values of φ fall within the range of values extrapolated from lunar cone penetration tests, but values of cohesion are substantially greater. This difference is attributed to effects of test stress levels and soil anisotropy.
Alternative Test Method for Resilient Modulus of Fine-Grained Subgrades
Authors: Drumm EC , Li Z , Reeves JS , Madgett MR 
Published: February 2009

Abstract
The mechanistic design of flexible pavement systems requires the specification of mechanical properties for asphaltic concrete, base course, and soil subgrade. The stiffness of the soil subgrade is represented by the resilient modulus, Mr, which is determined in the laboratory from cyclic triaxial tests and is usually a function of the level of applied stress. For a typical pavement project where numerous soils are encountered, cyclic triaxial testing to determine Mr for each subgrade soil may be too complex and time consuming to be applicable on a production basis. Therefore, alternative methods for the determination or estimation of Mr are appropriate and are in fact suggested in the 1993 AASHTO Guide for Design of Pavement Structures (AASHTO Guide 1993).
An alternative test method (ATM) was developed based on a falling weight impacting a standard Proctor specimen. A simple theoretical model was used to develop expressions for the modulus and deviator stress as a function of the measured acceleration during impact. An analysis was conducted to compare the state of stress in the ATM with that in a subgrade under a pavement. A prototype device was constructed and used to estimate the resilient response of 14 soils for which standard cyclic triaxial data were available. The ATM results compared well with the results from standard triaxial tests, and the ATM was able to consistently distinguish the low resilient modulus soils from those with high modulus. The ATM was shown to provide results suitable for many design applications and may be useful for reducing the number of standard tests required to characterize the subgrade Mr response for a pavement project.
Tests on Model Jacked Piles in Calcareous Sand
Authors: Chin JT , Poulos HG 
Published: February 2009

Abstract
This paper presents the results of a series of displacement-controlled cyclic axial loading tests of model jacked piles in dry calcareous sand. The tests were conducted using a large test facility comprising a test chamber 1.0 m in internal diameter and 1.55 m in height. Model instrumented aluminum jacked piles 50 and 100 mm in diameter were used to investigate scale effects on the degradation of skin friction capacity under cyclic loading conditions. Test results are presented for the response during jacking (installation), initial static compression loading, cyclic loading, and post-cyclic static compression loading response. It is shown that the degradation of skin friction is governed by the “cyclic slip displacement” model.
Analysis of Hydraulic Gradient Effects for Laboratory Hydraulic Conductivity Testing
Authors: Fox PJ 
Published: February 2009

AbstractA theoretical model is presented that characterizes the effect of hydraulic gradient on measured hydraulic conductivity in the laboratory. A closed-form equation is derived for the distribution of total head within a hydraulic conductivity test specimen as a function of specimen height, boundary stress conditions, compression index, and change of hydraulic conductivity index. From this expression, corresponding equations for the distributions of local pore pressure, effective stress, void ratio, hydraulic gradient, and hydraulic conductivity are presented. Two laboratory experiments were performed using a clay slurry to assess the validity of the theory: (1) an end-of-primary incremental loading consolidation test with direct hydraulic conductivity measurements, and (2) a rigid-wall hydraulic conductivity test with local pore pressure measurements. Using material properties obtained from the consolidation test, the theory predicted correctly the behavior of the hydraulic conductivity test specimen for two values of equivalent hydraulic gradient. It is concluded from this research that excessive hydraulic gradients applied during hydraulic conductivity testing can cause reductions in measured hydraulic conductivity. The magnitude of the effect is expected to be more important for normally consolidated soils with high compressibility, such as soft clays and soil-bentonite slurries.
Direct and Indirect Permeability of Fissured Tills
Authors: Hossain D 
Published: February 2009

AbstractComparison of direct and indirect measurements of water permeability on relatively large undisturbed and compacted Scottish till specimens in rigid-wall (Rowe cells) and flexible-wall (triaxial cells) permeameters shows the interaction of macro-fabric, test method, evaluation basis, effective stress, and possibly sidewall leakage. At low stresses, the sidewall leakage in a Rowe cell is the most likely cause of the directly measured permeability, kd, and pore-pressure-dissipation-based permeability, kp, becoming higher than settlement-based permeability, ks. Similarly, fissures raise permeability measured in both permeameters. Generally, kp is higher than ks (or volume-change-based kv from triaxial cells) with ka in between but closer to ks (or kv). The differences decrease with increasing stresses; the reduction rate for fissured specimens is dependent on fissure coating thickness and permeability.
Simplification of Soil Classification Charts Derived from the Cone Penetration Test
Authors: Zhang Z , Tumay MT 
Published: February 2009

AbstractThis paper presents a semi-empirical approach to simplify existing CPT and PCPT soil classification charts. This approach is based on two tendencies in current charts, namely soil type and in situ soil state. These charts may be simplified into one-dimensional soil classification systems by linear conformal mapping. Accordingly, several charts are simplified, and a comparison to in situ testing data indicates the conformity of the approach and formulas suggested. The simplified systems allow users to identify and describe in situ soil types (site stratigraphy) in a visualized or graphic manner. The results also display the overlaps among different soil types in a cone soil classification.
Rigorous Theoretical Analysis of a Flow Pump Permeability Test
Authors: Esaki T , Zhang M , Takeshita A , Mitani Y 
Published: February 2009

Abstract
With the growing importance of environmental issues in our society, extremely low-permeability geotechnical materials are being studied increasingly for their long-term stability and effectiveness in retarding the transport of hazardous wastes. Relatively rapid measurements of the permeability and specific storage of the materials, using relatively low hydraulic gradients, can be obtained with a constant flow pump and the corresponding theoretical analysis proposed by Morin and Olsen (1987). However, the accuracy of this method is limited because their theoretical analysis does not take into account the storage capacity of the experimental system. This paper presents a more general theoretical analysis and shows how it can be used to determine not only the permeability and specific storage of a test specimen, but also the storage capacity of the experimental system. Experimental data are presented that illustrate the accuracy and efficiency of the general theoretical analysis.
Evaluation of Sulfate Expansion in Soil-Cements
Authors: Ksaibati K , Huntington GS 
Published: February 2009

Abstract
This paper presents the results of an evaluation of internal sulfate attack in soil-cements. Differences in rates and amounts of expansion were evaluated for several aggregate types. Sulfate expansion of soil-cement was evaluated using a modified version of ASTM Test Method for Length Change of Hardened Hydraulic Cement Mortar and Concrete (C 157) that utilized a falling weight compaction procedure and large 76 by 76 by 286-mm bars. This paper compares this new test procedure with already established means of evaluating internal sulfate expansion of soil-cement. Expansion of small 25 by 25 by 286-mm bars compacted with a hand tamper was compared to expansion of the large bars compacted by a falling weight. Some small bars were cured in lime-saturated water, while others were cured in humid air. Much better results were achieved when curing took place in water. The new large bar method simulated field expansions better than the small bars. The use of small bars cured in lime-saturated water is recommended only when results are needed quickly. Large bars cured in water are recommended whenever time permits.
Rock Porosity Determinations Using Particle Densities Measured in Different Fluids
Authors: Passas N , Butenuth C , de Freitas MH , Bunatova V 
Published: February 2009

AbstractRock porosity, when calculated from measurements of bulk and particle rock density, is found to depend on the method used to determine these densities. The particle density, which is found experimentally, varies with the immersion fluid used; hence, the porosity determined depends on it, too. Organic fluids are recommended in standards for describing particle density for special applications; however, water is generally considered to be virtually inert when in contact with inorganic particles, particularly if the particles are composed of silicates. Thus, the results of measurements made using water as the immersion liquid are not considered to have been measurably affected by water. This paper shows that water does, in fact, alter measurably the value of silicate particle density obtained compared with measurements made using an organic fluid, viz., n-heptane. Explanations for this finding are under further consideration.
Round Two—Confined Compression: Young's Modulus, Poisson's Ratio, and Ultimate Strength
Authors: Pincus HJ 
Published: February 2009

Abstract
The Institute for Standards Research interlaboratory study of rock properties has provided precision statements for two additional ASTM rock-property test methods, D 5407 (Young's modulus and Poisson's ratio) and D 2664 (ultimate strength), both in confined compression. Three types of intact rock, Barre Granite, Berea Sandstone, and Tennessee Marble, were used in this study. Data were collected for both test methods at confining pressures of 10, 25, and 40 MPa, with four replications per rock type. The rock testing was preceded by pilot testing for Young's modulus and Poisson's ratio on aluminum alloy 2024 T351, with three replications. Young's modulus and Poisson's ratio were evaluated, for both aluminum and rock, from stress-strain data for the intervals from 25–50% and 40–60% of the maximum differential stress. Seven laboratories produced pilot data, and six of these laboratories produced data on rock for this report. Both the aluminum and rock specimens were prepared at central locations and were furnished ready for testing to the participating laboratories. For both elastic moduli, the overall normalized repeatability limit (“within laboratory”) for rock is about twice that for aluminum; the overall normalized reproducibility limit (“between laboratory”) for rock is about the same as that for aluminum.
A Circular Arc Test for Soil-Geosynthetic Interface Strength
Authors: Ghiassian H , Hryciw RD , Gray DH 
Published: February 2009

AbstractA circular arc test is described for determining the residual, or constant volume, interface strength parameters between soil and geosynthetics. The model is based on the variation of tension in a circular arc of fabric placed over a soil specimen and dead-loaded on two ends. The test method is simple and boundary conditions are well defined. The apparatus, theoretical formulation, and testing procedures are presented. The interface friction angle between dry Muskegon sand and three different materials: a cotton fabric, a fiber-glass mesh, and a nonwoven Geolon N35 filter, as determined by the circular arc test, are presented. Results of a staged circular arc test are also presented for the cotton fabric, and comparison to direct shear test results is made.
Development of an Accelerated Creep Testing Procedure for Geosynthetics—Part I: Testing
Authors: Farrag K , Shirazi H 
Published: February 2009

Abstract
The prediction of the long-term strength of geosynthetics is usually based on 10,000-h extension creep tests. Creep tests at elevated temperatures can accelerate testing duration to a reasonable time frame (1000 h) and the results can be extrapolated to longer time intervals. The paper presents the current state of practice in creep testing of geosynthetics and the development of testing equipment and procedure for accelerated creep tests at elevated temperatures. Creep tests were performed on high density polyethylene (HDPE) and polyester (PET) geogrids typically used in soil reinforcement applications.
Creep behavior at room temperature was first evaluated in 10,000-h tests at various creep loading levels (10 to 45% of ultimate strength of the geogrid Tmax). Accelerated creep tests were then conducted for 1000 h at various controlled temperatures from 24°C (75°F) to 72°C (160°F). These tests were conducted at the same loads to evaluate time-temperature-creep relationships of the geogrid.
Automatic Volume Measuring Device for Testing Dry Soils: “Martina”
Authors: Fioravante V , Capoferri R 
Published: February 2009

Abstract
A new automatic measuring device for testing dry granular soils in laboratory is presented. The device enables direct measure of volume changes of dry specimens by measuring gas that comes out or in during testing due to soil deformability. As the soil deforms, voids (which are supposed to be hydraulically connected to each other) change their volume; if they are part of a closed hydraulic circuit (any leakage is avoided) and gas pressure is kept constant by adjusting the total volume of such circuit, the amount of gas through soil voids is transferred to the measuring device, which varies its volume. The apparatus is described in detail as to its working principle. A strong effort was made to assess errors and to calibrate such apparatus as well as to evaluate its precision when used for triaxial testing. Finally, to validate its behavior, the most significant results obtained comparing dry versus saturated granular soil triaxial tests are here presented.
Compaction of Sand-Processed Clay Soil Mixtures
Authors: Howell JL , Shackelford CD , Amer NH , Stern RT 
Published: February 2009

Abstract
The effects of type of processed clay soil, curing period, and mixing procedure on laboratory compaction of sand-attapulgite clay (S-AC), sand-granular bentonite (S-GB), sand-powdery bentonite (S-PB), and sand-attapulgite clay-granular bentonite (S-AC-GB) mixtures are evaluated. Compaction is evaluated for total clay soil contents of 10, 15, and 20%. Different trends in optimum water content, wopt, and maximum dry unit weight, γdmax, versus clay soil content among the S-AC, S-GB, and S-PB mixtures are attributed, in part, to (1) the greater water sorptivity and lower swelling potential of attapulgite clay relative to the bentonites, (2) the larger particle sizes of the granular bentonite in the air-dried condition relative to the powdery bentonite, and (3) the possible correlation between the wopt and the plasticity index of the sand-bentonite mixtures. The Δwopt values and Δγdmax values resulting from one-day versus seven-day curing periods before compaction of the S-GB and S-PB mixtures are ∼0.5 percentage points and ≤0.08 kN/m3 (≤0.5 pcf), respectively, and result in different trends in γdmax versus bentonite content for the two types of sand-bentonite mixtures. Also, mixing the sand and bentonite in a dry condition before adding water consistently results in greater wopt and γdmax values than mixing the sand with the appropriate amount of water before adding the bentonite regardless of the type of bentonite. Finally, mixing the attapulgite clay and granular bentonite together in small amounts for each individual compaction point for the S-AC-GB mixtures consistently results in higher γdmax and wopt values relative to mixing the attapulgite clay and granular bentonite together in large amounts sufficient to cover all compaction points.
Development of an Accelerated Creep Testing Procedure for Geosynthetics, Part II: Analysis
Authors: Farrag K 
Published: February 2009

Abstract
A procedure for extrapolating creep strains to longer time intervals was developed. The procedure was based on applying time-shift factors to creep strain curves at elevated temperatures to establish a master strain curve for longer time intervals. The procedure was applied to creep test results on high density polyethylene (HDPE) geogrid tested at creep loads up to 40% of its maximum tensile strength Tmax and at temperatures up to 72°C (160°F). Temperature creep curves of 1000-h tests were shifted along the log-time scale to create 10 000-h master strain curves at each loading level. The established master curves were compared with experimental results of 10 000-h creep tests at room temperature and at the same loading levels. The shift factors were then applied to the creep curves to predict creep response for a duration of more than 100 000-h (about two cycles shift on the log-time scale from the initial 1000-h tests).
The analysis demonstrated the applicability of applying shift factors to elevated-temperature creep test results to predict the response at longer times for this type of geogrid. The analysis was applicable to creep loads up to 40% Tmax. The procedure, however, did not accurately estimate creep response at higher loading levels and temperatures where accelerated creep failure occurred.
Influence of Viscous Fluids on Properties of Sand
Authors: Zeng X , Wu J , Young BA 
Published: February 2009

Abstract
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

Abstract
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.