bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compaction Control of Earth-Rock Mixtures: A New Approach
Authors: Torrey VH , Donaghe RT 
Published: February 2009

Abstract
A new method for compaction control of earth-rock mixtures has been developed which permits the calculation of the maximum dry unit weight and optimum water content of the total material from corresponding values obtained on either the minus 3/4-in. (19.1-mm) or the minus No. 4(4.76-mm) fraction. The new concepts are substantiated by showing their applicability to a wide range of gradations of earth-rock mixtures tested by the U.S. Army Engineer Waterways Experiment Station and other previous investigators. Calculations of maximum dry unit weight and optimum water content of the total material from corresponding values for a fraction are made using a density interference coefficient and optimum water content factor which are shown to be linearly related to gravel content in the material in log-log coordinates. It is also shown that if a sufficient range in gravel content exists in the minus 3/4-in. (19.1-mm) fractions of the total materials, the log-log linear relationships among density interference coefficient, optimum water content factor, and gravel content can usually be obtained without large-scale compaction testing of the parent total materials. In essence, the new method provides project-specific “rock corrections” which accurately track the compaction parameters of the entire family of generically related total materials throughout the range in their gravel contents and maximum particle sizes.
Techniques for Assessing the Nonlinear Resilient Response of Unbound Granular-Layered Structures
Authors: Dastich I , Dawson A 
Published: February 2009

Abstract
The resilient stress-deformation characteristics of aggregates that form granular pavement layers are reviewed. A standardized plate bearing test (PBT) is proposed that separates resilient and permanent deformation readings and detects material stress dependency. A nonlinear, stress-dependent model proposed by Ehrler is used to reproduce the observed deformation behavior of a granular layer subjected to repeated plate bearing tests at different applied stress levels. The use of equipment exploiting the relationship between resilient behavior and the natural frequency of vibration of a mass resting on a semi-infinite half space (the natural vibration method—NVM) is described. The results predict granular pavement stiffnesses when a nonlinear, stress-dependent model is employed, and these are very simply related to PBT results obtained on the same material. The NVM approach may be more practical than the modified PBT procedure proposed as it can be used more quickly.
Consolidation Behavior of Soils
Authors: Sridharan A , Prakash K , Asha SR 
Published: February 2009

AbstractBased on Terzaghi's consolidation theory, percent of consolidation, U, versus the time factor, T, relationship for constant/linear excess pore water pressure distribution, it is possible to generate theoretical log10(H2/t) versus U curves where H is the length of the drainage path of a consolidating layer, and t is the time for different known values of the coefficient of consolidation, cν. A method has been developed wherein both the theoretical and experimental behavior of soils during consolidation can be simultaneously compared and studied on the same plot. The experimental log10(H2/t) versus U curves have been compared with the theoretical curves. The deviations of the experimental behavior from the theory are explained in terms of initial compression and secondary compression. Analysis of results indicates that the secondary compression essentially starts from about 60% consolidation. A simple procedure is presented for calculating the value of cv from the δ-t data using log10(H2/t) versus U plot.
Improvements to a Stress-Path Triaxial Cell
Authors: Aversa S , Vinale F 
Published: February 2009

Abstract
Stress-path triaxial cells are presently used all over the world. Accurate use of this type of apparatus allows an investigation into the mechanical behavior of soils with regard to a wide range of stress and strain. A correct evaluation of small-strain stiffness requires an accurate definition of the compliance curve of the apparatus and the possibility of performing tests in stress-controlled conditions. However, in the standard stress-path cell, compliance curves are often nonlinear and nonrepeatable. Moreover, in most standard stress-path apparatus, the pressure supply is limited to 1000 kPa, which makes it impossible to carry out stress-controlled tests at high confining pressures. The observation of these limitations prompted adjustments in the design of the cell, described in the present paper. With the revised design, it is possible to apply a deviatoric stress up to 1500 kPa under stress-controlled conditions with a cell pressure of 1000 kPa using a 1000-kPa pressure supply. The stiffness of the cell was also significantly increased, up to ten times the stiffness of the original design.
Granulometric Evaluation of Particle Size Using Suspension Pressure During Sedimentation
Authors: Zhang Z , Tumay MT 
Published: February 2009

Abstract
A new method, computerized granulometric analysis in suspension (C-GRAINS), is suggested for the sedimentation analysis of soil particles based on the relation between the specific weight and liquid pressure of a soil suspension. Theoretical aspects concerning this new testing method are discussed, and a prototype C-GRAINS system is fabricated accordingly. The general behavior of the new system is studied, and the corresponding sedimentation results are compared to current ASTM standards.
Liquid and Plastic Limits as Determined from the Fall Cone and the Casagrande Methods
Authors: Wasti Y 
Published: February 2009

Abstract
The shortcomings of the conventional methods of determining the liquid limit using the Casagrande apparatus and the plastic limit by rolling soil balls by hand have led to the investigation of the fall cone (cone penetrometer) as an alternative. The use of the fall cone test to determine the liquid limit has long been adopted by several countries, but the proposal to use this test to determine the plastic limit as well, redefined on the basis of a strength criterion, is rather recent. In this paper the liquid and the plastic limits as determined by these two procedures for a number of natural soils and artificial soil mixtures are presented. A comparative and critical survey of experimental results involving the use of various cones to obtain consistency limits is also included.
Geotechnical Properties of Expanded Shale Lightweight Aggregate
Authors: Valsangkar AJ , Holm TA 
Published: February 2009

Abstract
In recent years lightweight aggregates are being used increasingly in geotechnical applications. This paper presents results of large-size one-dimensional compression and direct shear tests performed on lightweight aggregate. The compressibility and shear strength characteristics of the lightweight aggregate are compared with those of normal-weight aggregate using the same experimental setup. Results of the direct shear tests performed to determine the angle of friction between the geotextile and lightweight aggregate are also presented. In addition, static shear modulus values as determined from model pile tests are presented and compared with those reported for normal weight aggregates.
Design of a Large Calibration Chamber
Authors: Sweeney BP , Clough GW 
Published: February 2009

AbstractThe design and operation of a conceptually simple, low-cost chamber for calibration of cone penetrometers and other in situ devices is described. The chamber weighs over 5500 kg and houses a 4400-kg soil sample that is 1.5 m in diameter and height. Operations in the chamber are automated using a self-equilibrating hydraulic insertion frame, a soil pluviation system for sand placement, a vacuum unit for removing sand, and an automatic data acquisition system. The results from a series of cone penetration tests in Monterey No. 0/30 sand, using standard and miniature cones, are also discussed. These tests indicate that the chamber design was successful and also that nearly homogeneous samples could be prepared at different relative densities using interchangeable rainer plates.
Shear Zone Characterization in Sands by Carbowax Impregnation
Authors: Hryciw RD , Irsyam M 
Published: February 2009

Abstract
A procedure is presented for determining the void ratio distribution of very small zones in soil by carbowax impregnation. If the wax is injected slowly, complete filling of voids occurs and volume measurements become unnecessary. Thus, even irregularly shaped volumes can easily be characterized. The technique was employed in determining the void ratio distribution in the intrarib region of a ribbed inclusion in sand during direct cyclic shearing. The measured void radios supported magnified video observations.
Evaluation of Allowable Pressure Under Foundations
Authors: Reznik YM 
Published: February 2009

Abstract
To understand the surcharge effect on test-loading results, water-saturated loessial soils were tested by bearing plates of different sizes in open pits and boring holes. All pit bottoms were accurately prepared for experiments. The surcharge around the bearing plate with an area of 600 cm2 was simulated by special equipment. Results of field experiments showed that the proportionality limit for water-saturated loessial soils tested without surcharge was at least 25% less than obtained with the surcharge.
Automated Triaxial Testing of Soft Clays: An Upgraded Commercial System
Authors: Sheahan TC , Germaine JT , Ladd CC 
Published: February 2009

AbstractThe paper evaluates the ability of a widely used automated commercial testing system to perform Ko consolidated-undrained triaxial compression and extension (CKoUC/E) tests on normally consolidated clay. The commercial system uses control software on a microcomputer to operate three digital pressure-volume controllers that control and measure the pore water pressure and volume, the radial stress, and the axial stress and strain for a specimen within a Bishop and Wesley Hydraulic Triaxial Apparatus. Because the commercial system calculates axial stress and strain by relying on indirect measurements assuming idealized behavior of the axial loading assembly, the system was modified to directly measure axial stress and strain. The system was also enhanced to enable shear in triaxial extension and to improve certain other testing procedures. Comparison of results from CKoUC/E tests obtained by the resulting reference system with prior data on resedimented Boston Blue Clay shows good to excellent agreement in 1-D compressibility and undrained stress-strain-strength characteristics. In contrast, stresses recorded by the commercial system resulted in significant overestimates of preconsolidation pressure, undrained strength, and the effective stress envelope, primarily caused by unquantifiable behavior of the axial loading assembly. Based on these results and other experience, the paper suggests features warranting special attention when selecting a commercially available automated triaxial system in order to upgrade the experimental capabilities of a laboratory.
Effect of Backfill Thrust on Vertical Pressure Distribution in Reinforced Soil Model Walls
Authors: Ashaari Y , Arenicz RM 
Published: February 2009

Abstract
The magnitude and distribution of vertical stress are required for the design of reinforced soil wall. A laboratory investigation utilizing a physical model of reinforced soil wall was performed to determine the effect of backfill thrust on the vertical pressure distribution within the reinforced zone. Results obtained were compared with those predicted by the theoretical vertical pressure distribution (uniform, trapezoid, and Meyerhof's).
The model wall behavior, particularly the distribution of vertical stress within the reinforced zone of the structure, was investigated in four series of tests with different boundary conditions and construction procedures. The results obtained were, as expected, different from either of the three theoretical pressure distributions. It was found that thrust of backfill material placed at the back of reinforced zone reduces the vertical pressure near the end of reinforcement strips while increasing it in the remaining part of the reinforced zone. The reduction of pressure near the strip ends conforms to the trapezoid theory. However, the maximum increase in pressure does not occur at the facing as predicted by the theory.
Field Hydraulic Conductivity Tests for Compacted Soil Liners
Authors: Sai JO , Anderson DC 
Published: February 2009

AbstractField hydraulic conductivity tests are required to determine the in situ hydraulic conductivity of compacted clay soils used in the liners for hazardous waste management facilities. The test must be capable of measuring hydraulic conductivities of 1 × 10−9 m/s or less, and the values obtained must be representative of the overall soil liner. Few of the methods available are capable of both measuring low hydraulic conductivities and obtaining representative values. Test methods which meet these requirements include large single-ring infiltrometers, sealed double-ring infiltrometers, and collection lysimeters. The main drawback in the use of collection lysimeters is that it can take months to obtain steady-state hydraulic conductivity values. Sealed double-ring infiltrometers are practical to use and have the advantage of few ambiguities in the experimental procedures, few possibilities for yielding false low values, and are large enough to yield results representing the overall liner characteristics.Infiltrometers used on compacted soil liners should cover at least one elementary volume (REV) (e.g., at least 2 m2), and, in addition, at least three separate tests should be conducted to characterize spatial variability of the field hydraulic conductivity.
A Biaxial Apparatus for Testing Soils
Authors: Drescher A , Vardoulakis I , Han C 
Published: February 2009

Abstract
A biaxial compression apparatus for investigating shear-band formation and growth in dry and water-saturated sand and clay specimens is described. This apparatus is a modification of the device designed by Vardoulakis and Goldscheider [1] for testing planar shear banding in sands. The modifications involve improved axial load guidance, low friction linear bearing, and enhanced load and displacement measurement instrumentation. The apparatus allows for accurate prelocalization material behavior and shear-band growth investigation. Specimen preparation and data evaluation procedures are described, and test results on dry Ottawa sand are presented.
Design and Testing of a Synthetic Clay Soil
Authors: Lewis MJ , Blaney GW 
Published: February 2009

Abstract
A synthetic clay soil mixture was designed and fabricated to comply with similitude requirements set forth in a dynamic scale-model pile group foundation test. The prototype soil was a stiff, fissured, overconsolidated clay soil at the University of Houston Pile Test Facility. The dynamic response of the model soil was determined through testing by resonant column/torsional simple shear methods and by seismic wave velocity tests in the model test bed. The synthetic clay soil was more nearly linear elastic to higher strain levels with less damping than natural clays. The ability of the soil to regain its strength after disturbance was beneficial to the scale-model tests. The design, fabrication, and testing procedures utilized to obtain an appropriate geotechnical material for scale-model soil/structure interaction tests is detailed in this article.
Abrasion Tests for Railroad Ballast
Authors: Selig ET , Boucher DL 
Published: February 2009

Abstract
Mechanical abrasion tests are an important basis for evaluating the suitability of rock for use as railroad ballast. This paper considers three such tests: Los Angeles abrasion, the test primarily used by North American railroads; Deval abrasion, the test primarily used by British Rail; and mill abrasion, a relatively new test being proposed for use in North America. The mill abrasion test is similar to the Deval test. Previous evaluations of the Deval and mill abrasion tests are summarized. Then test data generated by the authors are presented to show the effect of factors influencing the mill abrasion test results. Finally, mill and Los Angeles abrasion results obtained on a wide range of rock type are compared and evaluated using petrographic analysis.
Ranking of rock type by the mill test is different than by the Los Angeles test. The products of abrasion are quite different, too—the mill test primarily produces particles smaller than the No. 200 sieve, while the Los Angeles test primarily produces particles larger than the No. 200 sieve. Thus these two tests appear to be influenced by different rock structural characteristics. In the mill and Deval tests, the amount of abrasion increases with increasing particle size. Also, the amount of abrasion is significantly greater for freshly crushed particles than for worn particles. In the mill test the abrasion is significantly greater when the test is conducted wet than when conducted dry. The petrographic analysis was useful in explaining the differences in results for the various rock type.
Design, Construction, and Testing of a Large-Scale, Radial Fracture Flow Model
Authors: Atkinson LC , Gale JE 
Published: February 2009

Abstract
Materials and procedures used in previous laboratory studies of flow in fractures were reviewed. Based on this review, a 3-m-high by 1.5-m-diameter cylindrical radial flow model with a single horizontal fracture was designed and constructed out of concrete. The fracture was created by placing a sheet of geotextile between the top and bottom halves of the cylinder during pouring of the concrete. Twenty-eight piezometers were cast in-place in the fracture plane, and displacement transformers were installed both on the circumference of the cylinder and in the wellbore to measure fracture deformation. The model also incorporated features designed to allow withdrawal and injection tests to be conducted with different flow boundary conditions, applied loads, and wellbore diameters. This laboratory setup was used to investigate flow and deformation in the immediate vicinity of a vertical well intersecting a single rough, deformable, horizontal fracture at flow rates of practical interest to the geotechnical and petroleum industries.
Corrections for Membrane Strength in the Triaxial Test
Authors: Kuerbis RH , Vaid YP 
Published: February 2009

AbstractEquations based on elastic thin cylindrical shell compression theory are developed for correcting stresses for membrane strength in a triaxial test. The corrections are expressed in terms of the unstretched dimensions, the diameter and thickness of the membrane, the axial and volumetric strain of the cylindrical membrane cavity referenced to its unstretched dimensions, together with E and v of the membrane rubber. The development specifically considers changes in membrane thickness as they occur during the straining process, and in particular its influence on the specification of E of the membrane. Direct experimental verification of the derived stress correction is provided in support of their validity.
Classification of Expansive Soils by Sediment Volume Method
Authors: Sridharan A , Rao SM , Joshi S 
Published: February 2009

Abstract
A soil expansivity classification is proposed based on the sediment volume ratio defined as the ratio of the sediment volume in 0.025% sodium chloride solution to that in kerosene. The results of the proposed classification agree well with one based on the oedometer test results of compacted soil specimens.
Fabrication of Silty Sand Specimens for Large- and Small-Scale Tests
Authors: Brandon TL , Clough GW , Rahardjo PP 
Published: February 2009

AbstractIn the course of research concerning the relation of cone penetration results and liquefaction resistance, it was necessary to develop a reliable method for preparation of silty sand specimens for laboratory triaxial testing (3.6 by 7.1 cm in diameter) and for a large-scale calibration chamber (1.5 by 1.5 m in diameter). The objective was to simulate the in situ soil fabric and to allow for creation of a range of densities. Four alternate procedures were studied, including kneading compaction, pluviation through air, pluviation through vacuum, and consolidation from a slurry. The primary conclusions from the research were:1. Kneading compaction is effective in producing laboratory specimens with a range of densities, but it is not an effective procedure for placing these materials in the large-scale calibration chamber.2. Pluviation through air and vacuum creates specimens with unrealistically high void ratios. Obtaining a range of densities was not possible.3. Slurry consolidation proved to be successful in creating specimens with a range of densities and was the technique chosen for the calibration chamber.Only vertical drainage was used in the calibration chamber to avoid formation of a specimen with a soft core surrounded by stiff sides. Eighteen to twenty days were required for consolidation, and the density of the specimens along a vertical profile varied by no more than 6% from the average density. There was little evidence of segregation of fines.
Calibration of a Dynamic Penetrometer for Compaction Quality Control of Boiler Slag
Authors: Acar YB , Puppala AJ , Seals RK 
Published: February 2009

AbstractA dynamic penetrometer was designed for the purpose of evaluating compaction quality in fills constructed with boiler slag. Laboratory and field calibration tests were conducted to study the effect of densification on dynamic penetration resistance. The effects of specimen preparation method (pluviation and impact compaction) and saturation on dynamic penetration resistance were investigated in the laboratory. A 0.91-m (3-ft)-deep test fill with dimensions of 6.1 m (20 ft) by 30.5 m (100 ft) was prepared in the field. Dynamic penetration resistance and in situ densities were recorded in this slag fill after 0, 2, 4, 6, 10, and 16 passes of a smooth drum vibratory roller of 5.6 tons (11.2 kips). The field-resistance values were compared with laboratory values. Charts are provided to aid both in selecting the lift thickness/number of roller passes and also for field assessment of densification in boiler slag using the dynamic penetrometer.
Expansive Soils under Cyclic Drying and Wetting
Authors: Dif AE , Bluemel WF 
Published: February 2009

Abstract
An approach was developed to study the swell-shrinkage behavior of expansive soil samples in the laboratory under the action of the actual load to which the soil will be subjected in the field. The fatigue phenomenon due to cyclic drying and wetting has been under investigation, and this paper describes in detail the modified oedometer used in this investigation and the testing procedure adopted. Some typical test results are used to illustrate the fatigue behavior of undisturbed expansive soil specimens during cyclic drying and wetting.
Piezo Film Technology and Applications in Geotechnical Testing
Authors: Santamarina JC , Wakim TN , Tallin AG , Rab F , Wong J 
Published: February 2009

Abstract
Piezo films are thin, piezoelectric membranes that can be used both as source or as receiver. They may be adapted to a variety of in situ and laboratory geotechnical testing needs. This paper summarizes fundamental concepts in piezo film technology and the physical properties of this material. The principles behind common utilizations are reviewed, and three geotechnical applications are described: a low-cost field sensor and modified triaxial and oedometer cells to measure low-strain moduli in resonant and pulse mode.