bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulatory mode preferences for autonomy supporting versus controlling instructional styles
Authors: Pierro Antonio , Presaghi Fabio , Higgins Tory E. , Kruglanski Arie W. 
Published: February 2009

Background Three studies carried out in educational settings examined determinants of teacher's instructional styles and students' degree of satisfaction with the learning climates created by such styles.Aims Based upon regulatory mode theory, Studies 1 and 2 tested the hypotheses that teachers' locomotion orientation will be positively related, and their assessment orientation will be negatively related, to autonomy supportive (vs. controlling) instructional styles. Study 3 tested the hypothesis that students' regulatory mode will exhibit a fit effect with the prevalent learning climate in their school.Samples Participants for Study 1 were 378 teachers (278 females); for Study 2 were 96 teachers (65 females); and for Study 3 were 190 students (all males).Method Participants completed questionnaires that included measures of teaching styles (Studies 1 and 2), perceived learning climate and satisfaction (Study 3), and regulatory mode orientations (Studies 1 and 3). In Study 2 regulatory mode orientations were experimentally induced.Results Results confirmed that teachers' autonomy supportive versus controlling styles were positively related to their locomotion orientations and negatively related to their assessment orientation, and that students with a stronger locomotion (vs. assessment) orientation reported a higher level of satisfaction when the learning climate was perceived as autonomy supportive (vs. controlling).Conclusions The present studies show that teachers' preference for adopting an instructional style is influenced by their regulatory mode orientations, and that the effects of a learning climate on students' satisfaction are contingent on a fit between type of learning climate and students' regulatory mode orientations.
Determination of Collapse Potential of Soils
Authors: Lutenegger AJ , Saber RT 
Published: February 2009

AbstractA review of various criteria that have been proposed to identify collapsible soils and test techniques, which are used to quantify the amount of collapse, is presented. The results of a series of laboratory single and double oedometer collapse tests conducted on three metastable loess soils are presented to illustrate problems associated with investigating collapse behavior of soils. Guidelines are proposed for developing a standard test procedure.
Helical Probe Tests: Initial Test Calibration
Authors: Yokel FY , Mayne PW 
Published: February 2009

Abstract
Helical test probes of different sizes suitable for shallow (1.8-m) in-situ soil exploration and compaction control were developed and tested in different soils alongside traditional in-situ tests, including Standard Penetration tests (SPT), cone penetration tests (CPT), dilatometer tests (DMT), and in-situ density tests. The helical probe test (HPT) is a quick and economical test, which can be performed by a single person in less than 10 min, making it very attractive for construction field testing on geotechnical projects. The torque necessary to insert the probe is used as a measure of soil characteristics. Preliminary studies indicate that the HPT test correlates well with the SPT test and the correlation is not sensitive to the soil type (particle size); the HPT test correlates well with the CPT test, but the correlation is sensitive to the soil type; and the HPT/SPT and HPT/CPT correlations are consistent with existing data on SPT/CPT correlations. After site calibration, the HPT torque can be used to estimate relative compaction and in-situ density of compacted soils.
Effect of Testing Procedure in Ring Shear Tests
Authors: Anderson WF , Hammoud F 
Published: February 2009

Abstract
This technical note describes a comparison between the results obtained from single-stage and multistage ring shear tests on two different types of normally consolidated clay. The results confirm the brittle behavior of normally consolidated soils containing a high proportion of clay particles and the curved nature of the residual stress failure envelope. Detailed examination of the test data shows that while the multistage technique offers a considerable advantage in terms of the test duration, it may give erroneous results for soils with a high proportion of platy clay particles.
The Behavior at the Shrinkage Limit of Clay Undergoing Drying
Authors: Williams DJ , Sibley JW 
Published: February 2009

Abstract
In this paper, possible links between the shrinkage limit and distinct changes in other properties of a clay soil undergoing drying are discussed. These properties include the volumetric air content of the soil, the heat of wetting, the tensile strength, the total suction, and the thermal resistivity of the soil. The distinct changes are of interest in themselves, and possible explanations for them are briefly discussed. For soil under extremely dry conditions, more importance should perhaps be attached to using the shrinkage limit as an index to changes in soil behavior, and this topic warrants further research.
Techniques for Estimating the Longevity of Lime-Treated Expansive Clays
Authors: McCallister LD , Petry TM 
Published: February 2009

Abstract
Two techniques are presented that investigate the possibility of estimating the longevity of lime-treated expansive clays subjected to leaching. The techniques are based on analyzing calcium concentrations and pH changes within accelerated leached laboratory specimens and their leachates during the leaching process. The accelerated leach times required to produce specific calcium concentrations and pH in the laboratory are converted to actual field leaching (or percolation) times by using developed time scale factors.
The techniques are tested for validity by correlating estimated calcium concentrations and pH values of field lime-treated clays to the actual results of field lime-treated clay layers of various known ages. The correlations showed that pH estimations were within an average of 13% of measured values, while estimated calcium concentrations remaining in the soil-lime layers were within an average of 18% of measured values.
Membrane Penetration in Triaxial Tests
Authors: Boháč J , Feda J 
Published: February 2009

Abstract
Volumetric deformations of triaxial specimens of sand measured with a burette are burdened with an error caused by a rubber membrane penetrating into the peripheral voids of the specimen. This effect is of the same order of magnitude as volumetric deformation of the soil skeleton and should be eliminated. To this end, a method has been proposed based on the K0-stress path. Membrane penetration for the particular material has been approximated by logarithmic and hyperbolic curves. The resulting correction considerably surpasses most published expressions because the latter usually do not consider the porosity of specimens.
Incinerator Residue for Roads
Authors: Aziz MA , Ramaswamy SD 
Published: February 2009

Abstract
A study was conducted by the authors to assess the feasibility of using incinerator residue in road construction. Residues from Singapore incinerators were characterized. Various combinations of mixes comprising local clayey-silty-sandy soil and incinerator residue with or without lime were tested for their suitability for use as road subbase/subgrade. Also, bituminous mixes comprising varying proportions of incinerator residue and granitic aggregates were tested to determine their suitability in road surfacings. This study has revealed that the incinerator residue, although inferior in quality as compared to granitic aggregates for use in dense bituminous mixes for road surfacings, has properties that justify applications in areas where high-quality aggregate is not required. The road subgrade soils can be economically stabilized by using an admixture of incinerator residue from 50 to 75% along with as low as 2.5 to 5% lime. For bituminous mixes, the optimum binder requirement of 10 to 12% makes it quite expensive. However, the use of incinerator residue as unbound base or subbase material with or without blending with natural aggregates is feasible. The incinerator residue also has the potential for use as a free-draining friction course using only 4 to 5% bitumen. Because of its compatibility to bitumen adhesion, stripping is considerably resisted.
The Simple Pile Load Test (SPLT)
Authors: Lee MW , Paik SW , Lee WJ , Yi CT , Kim DY , Yoon SJ 
Published: February 2009

Abstract
For the design of pile foundations, estimation of the pile-bearing capacity is important because the size and number of piles are determined from the estimation. Although there have been many different methods predicting pile-bearing capacity, no one method provides reliable predictions except for methods based on actual loading tests. Due to time and money constraints, conventional pile-load tests tend to be limited and, consequently, design relies on relatively high factors of safety. In this paper, a new and simple method of performing pile-load tests is introduced. The suggested method uses a separable pile shoe with a reduced-size sliding core and has proved to be efficient in terms of both time and cost. By choosing the newly developed testing method, a more economical pile design can be attained.
Indirect Tension Tests on Rock—Analytical/Numerical Correction for Material Bimodularity
Authors: Chen R , Stimpson B 
Published: February 2009

Abstract
Many rocks have different deformational properties when loaded in tension and in compression. This property is referred to as bimodularity. The influence of bimodularity on four of the most commonly utilized indirect tension testing methods for measuring the tensile strength of rock is investigated analytically and numerically in this paper. These indirect tension methods include the three-point beam-bending test, the hydraulic extension test, the Brazilian test, and the ring test. It is shown that tensile strengths for rock derived from these tests are overestimated if the normal assumption of equal moduli in tension and compression is made. The actual tensile strength may be determined if the moduli ratio in tension and compression is known.
Ultimate Bearing Capacity of Rectangular Foundations on Geogrid-Reinforced Sand
Authors: Omar MT , Das BM , Yen S-C , Puri VK , Cook EE 
Published: February 2009

Abstract
Model test results for the ultimate bearing capacity of rectangular surface foundations supported by geogrid-reinforced sand are presented. The tests were conducted using one type of sand at one relative density of compaction with only one type of geogrid. The length-to-width ratios of the model foundations were varied as 1, 2, 3, and ∞. Based on the model test results, the maximum required depths of reinforcement and the sizes of the geogrid layers to obtain maximum-bearing-capacity ratios have been presented.
Large-Scale Triaxial Compression Testing of Geocell-Reinforced Granular Soils
Authors: Bathurst RJ , Karpurapu R 
Published: February 2009

Abstract
The paper describes the results of a series of large-scale triaxial tests carried out on 200-mm-high isolated geocell-soil composite specimens and unreinforced soil specimens. Two different aggregate soils were used in the test program. The reinforced specimens were tested with a height-to-diameter ratio of unity, which matches the dimensions of these systems in a typical base reinforcement application. The results illustrate the stiffening effect and strength increase imparted to the soil by the enhanced confinement effect. Comparison of reinforced and unreinforced soil specimens shows that the frictional resistance described by the peak friction angle of the soil infill is applicable to the composite structure as well. A simple elastic membrane model can be used to estimate the additional apparent cohesion present in the composite structure.
Estimating Water Content of Soils from Electrical Resistivity
Authors: Kalinski RJ , Kelly WE 
Published: February 2009

Abstract
Electrical resistivity has been demonstrated to be an effective predictor of various soil hydraulic properties including water content, degree of saturation, and hydraulic conductivity. Standardized laboratory procedures for measuring soil electrical resistivity are based on the use of the Miller soil box for determining soil corrosive potential from soil resistivity. However, these procedures and the Miller soil box do not allow for the flexibility in measurements necessary to develop explicit relationships between soil resistivity and hydraulic properties. As an alternative to the use of the Miller soil box, circular four-probe resistivity cells provide a measurement method that can be used to develop explicit relationships between soil resistivity and hydraulic parameters. For a test experiment, relationships were developed where volumetric water content could be estimated from soil resistivity with a standard error of 0.009.
Some Experiments on Restrained Shrinkage of Clays Undergoing Drying
Authors: Sibley JW , Williams DJ 
Published: February 2009

AbstractThis paper describes engineering applications which show the engineering significance of testing the phase composition of soils, including determining the level of water saturation. It further explains why, in order to accurately model in situ conditions in soil deposits, it is necessary to test the phase composition of soil under conditions of horizontal restraint and changing moisture content. The paper reviews the lineal measurement method of Sibley and Williams (1989), which was initially developed to test unrestrained clays. The method has now been adapted for use in characterizing phase relationships in horizontally restrained soil specimens undergoing drying. Results obtained using the new test have drawn attention to the fact that while soils undergoing drying are invariably restrained by naturally occurring mechanisms, the level of this restraint may vary widely. A useful index of the level of restraint applied to a slurried soil specimen undergoing drying is the moisture content at which initially 1-D (vertical) shrinkage behavior becomes isotropic.
Shear Strength of Very Soft Clay-Sand Mixtures
Authors: Tan T-S , Goh T-C , Karunaratne GP , Lee S-L 
Published: February 2009

Abstract
To treat a deposit of clay slurry in situ, sand is often added with the aim of trapping the sand in the upper portion of the slurry. The presence of the trapped sand may directly improve the shear strength of the slurry or contribute indirectly to the improvement by accelerating the consolidation. For this treatment to be effective, an important consideration is the improvement in the shear strength of the slurry as sand is added. A laboratory study of this is reported here. To rapidly determine the shear strength of the mixture, the fall cone method and a penetration test that was developed to measure very low shear strength were used. For the clay slurries studied, the added sand grains seemed to “float” in the clay without increasing the shear strength if they were sufficiently far apart. Treating the clay slurry as a fluid filling the “voids” in the sand, the void ratio of the sand for which a marked increase in shear strength is observed is about 5. The liquid limit of the mixture is also found to follow approximately a linear mixture law unless the amount of sand added is enough to ensure that the void ratio of the sand is less than 5, which is in agreement with the earlier result.
An Approximate Method for Estimating the Consolidation Behavior of Soft Sensitive Clays
Authors: Joshi RC , Achari G , Griffiths FJ 
Published: February 2009

Abstract
An approximate, semi-theoretical method to determine the complete consolidation curve of undisturbed sensitive soils from index properties and in situ undrained shear strength is presented. The consolidation curve for the soft sensitive soils consists of three distinct zones. In order of increasing stress, these zones are described as cemented, transitional, and uncemented zones. A relationship between undrained strength and preconsolidation stress of such soils is employed in the prediction of the stress level at which the cemented zone terminates. The slope of the stress path for the loading of sensitive soils during the transition phase of consolidation is less than the slope during the cemented phase. Further, assuming that the stress path in the transitional phase is a straight line at a constant angle to the p′ axis, a relationship between the end of the cemented and the end of the transitional zones of behavior can be derived. Since sensitive soils in the uncemented zone behave similarly to normally consolidated soils, the entire consolidation curve can be approximated.
An Image Analysis Method for Studying Movements in Granular and Solid Bodies
Authors: Gustafsson L , Knutsson S 
Published: February 2009

Abstract
A method based on image analysis of video recordings is presented for studying and measuring movements in granular materials. The method is easy to use, does not require any tracers, and makes extensive experiments feasible. Calibration tests show good repeatability. Measurements are presented of movements in a sand mass into which a piston is driven. The method is also useful for studying the deformation of solid bodies. The deformation of undrained clay specimens subjected to uniaxial forces is demonstrated using the proposed method.
Centrifuge Modeling of Laterally Loaded Pile Groups in Sands
Authors: McVay M , Bloomquist D , Vanderlinde D , Clausen J 
Published: February 2009

Abstract
Presented is a novel apparatus to drive and laterally load groups of six to nine piles in flight. The main component of the device is a flat plate with multiple apertures which are opened or closed through pneumatic solenoids while being raised or lowered with stepping motors via a PC. Presently, both lateral load versus deformation and load distribution within the rows can be measured.
Testing on both loose and medium dense sands at three and five-pile-diameter spacings have been completed for free-headed groups of nine piles. It was found that as the soil's density increased, so did the group's lateral resistance as well as the variation from row to row. The five-pile-diameter groups carried larger lateral loads and resulted in a more even load distribution from row to row than its three-diameter counterpart. Work is underway to test larger groups as well as inclined piles.
Laboratory Investigation on Bitumen Coating and Polyethylene Sheeting for Downdrag Reduction in Piles: A Comparative Study
Authors: Tawfiq KS 
Published: February 2009

Abstract
In this study, the polyethylene sheeting method for downdrag mitigation in piles has been investigated along with the conventional bitumen coating method. A large number of concrete blocks were prepared with different arrangements of bitumens and polyethylene sheets and tested in the laboratory using direct shear apparatus. The shear resistance of the concrete-bitumen-soil specimens was susceptible to changes in temperature, strain rate, and normal stresses. Bitumen-coated specimens tested with crushed limestone exhibited the highest friction. Soil particle penetration into bitumen doubled the shear resistance of the bitumen coating. Factors that govern the shear behavior of bitumen coating were found to slightly affect the friction characteristics of the concrete-polyethylenesoil specimens. According to the laboratory results, furnishing the concrete blocks with two 6-mil (0.15-mm) polyethylene layers reduced the shear resistance by 78%. More reduction could be achieved from the two oil-lubricated polyethylene sheets. This layering arrangement provided the most effective performance (95% efficiency) for the polyethylene sheeting method.
Impact-Echo Response of Hollow Cylindrical Concrete Structures Surrounded by Soil and Rock: Part I—Numerical Studies
Authors: Lin J-M , Sansalone M 
Published: February 2009

Abstract
The studies summarized in this paper and the following paper in this issue demonstrate that the impact-echo method can be used for integrity testing of concrete pipes, mine shaft liners, and tunnel liners in contact with soil or rock. Results obtained from numerical (finite element) studies are presented in this paper (Part I), and results obtained from experimental studies on mine shaft liners are presented in the following paper (Part II). These results show that the impact-echo response depends upon the acoustic properties of the surrounding material, as well as on the acoustic properties, geometry, and condition of the concrete structure. It is shown that cracks and voids in the concrete structure can be detected independent of the surrounding material. If the concrete structure is solid, the thickness of the concrete can be determined, except when the acoustic properties of the rock and concrete are similar and the concrete is in contact with the rock. The presence of delaminations or voids (air- or water-filled) at the concrete/rock interface can be identified when the acoustic impedance of the rock is similar or larger than that of the concrete.
A New Combined Servo-Controlled Loading Frame/Direct-Shear Apparatus for the Study of Concrete or Rock Joint Behavior Under Different Boundary and Loading Conditions
Authors: Mouchaorab KS , Benmokrane B 
Published: February 2009

Abstract
A new combined servo-controlled loading frame/direct-shear apparatus has recently been developed at the Civil Engineering Department of Université de Sherbrooke. This direct-shear device is capable of shear testing of rock joints under constant normal stiffness or constant normal load boundary conditions. Due to its combination with a servo-controlled loading frame, it allows load as well as strain and stroke control, including static and cyclic paths. This paper describes this direct-shear apparatus and illustrates results of static and cyclic shear tests undertaken on circular-section rock specimens with irregular interface geometry and on regular-shaped interface specimens made from cement-based mortar.
A General Dynamic Model for the Resonant Column/Quasi-Static Torsional Shear Apparatus
Authors: Ashmawy AK , Drnevich VP 
Published: February 2009

AbstractA new model is proposed that allows for more general boundary conditions at both the active and passive ends of resonant column apparatus, especially those incorporated within the resonant column/quasi-static torsional shear devices. The improved three-degree-of-freedom model can be used in order to obtain more accurate measurements of the dynamic properties of tested soils when the base and the reaction mass of the apparatus are not perfectly fixed. This becomes particularly important in the hybrid resonant column/quasistatic torsional shear apparatus where the load cell located below the bottom platen provides additional flexibility to the passive end and the inertia of the reaction mass of the Hardin-type oscillator is relatively small. The analysis confirmed that use of the model is particularly important if the natural frequency of the soil-apparatus system is close to that of the passive end or reaction system, and that the calculated modulus and damping values can be highly inaccurate if simplified boundary conditions are assumed. Such situations especially occur when very soft soils, very stiff soils, or rock specimens are tested. The solution was programmed in a spreadsheet where both the shear modulus (G) and the damping ratio (D) are established for a given set of measurements and apparatus constants. In order to obtain the necessary apparatus constants, calibration procedures are presented for a resonant column/quasi-static apparatus. Comparison of existing models and the new solution to the observed response for a rubber testing specimen showed that the three-degree-of-freedom assumption is more accurate in modelling the apparatus boundary conditions.