bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Swelling During Saturation in Triaxial Tests in Clays
Authors: Cho Wanjei , Holman Terence P. , Jung Young-Hoon , Finno Richard J. 
Published: March 2009

Abstract
Effects of swelling during saturation in triaxial tests on compressible Chicago glacial clays are assessed from results of triaxial compression tests on block samples cut from excavations, thin-wall Shelby tube samples, and reconstituted specimens. The results are presented in terms of the stress-strain response during saturation, k0 reconsolidation and shearing. Bender element tests were also performed to investigate the effects of swelling on the shear wave velocities during k0 reconsolidation. Results showed that the swelling during saturation lowered the shear wave velocity, thereby inferring a change in the original structure of natural clay. Responses at strains less than 0.01 % were most affected by the saturation-induced swelling. To minimize these changes, it is recommended that the measured residual stress is applied prior to saturating the soil. Based on these results, the saturation stage should be considered as much a part of a triaxial test as consolidation and shearing.
Rapid Pseudo-Static Measurement of Hysteretic Capillary Pressure-Saturation Relationships in Unconsolidated Porous Media
Authors: Chen Lixia , Miller Gerald A. , Kibbey Tohren C. G. 
Published: March 2009

Abstract
An automated system was developed for a rapid measurement of detailed hysteretic capillary pressure-saturation (Pc-S) relationships, including primary drainage, main imbibition, and scanning loops. The method makes use of a slow-dynamic (pseudo-static) measurement method which is able to duplicate static results while expanding the pressure range over which high permeability capillary barriers can be applied, and increasing the quantity of hysteretic data that can be collected. The method is demonstrated for two sands and three silts for capillary pressures as high as 1000 cm water (98 kPa). For the experiments shown, primary drainage and main imbibition loops were completed within approximately 6.5 h for all materials, with full runs, including multiple scanning curves, completed in less than 20 h. A model for selection of pressure rates needed to duplicate static results is presented and is found to produce results consistent with empirically-determined rates. The model also predicts the effects of system resistance on dynamic response and is found to be in good agreement with experimental results, particularly for slower rates approaching those needed for pseudo-static conditions.
A Multi-purpose Platform for Horizontal Subsurface Investigation
Authors: Ahn T , Allouche EN , Yanful EK 
Published: March 2009

Abstract
Site characterization using horizontal directional drilling (HDD) can provide an effective means of evaluating the geotechnical and geoenvironmental characteristics of sites with limited access such as beneath structures, roads, and runways.
The Smart Subsurface Horizontal Investigation Probe (SSHIP) is an innovative platform capable of investigating the geotechnical and geoenvironmental properties along a horizontal alignment by combining an array of miniature sampling tubes and a logging tool. The device is controlled from the surface and can transmit data in real-time over a distance of up to 300 m. The results of bench-scale tests aimed at evaluating the usefulness of two miniature sensors, a miniature resistivity probe (MRP) and a miniature cone penetrometer (MCPT), for various soil conditions, are presented.
Combining sampling, logging, and real-time communication capabilities, the SSHIP supports exciting new potential applications in the areas of geotechnical and geoenvironmental site investigations.
Stress-Strain Behavior of a Granular Fill Measured by a New Plane-Strain Apparatus
Authors: Wanatowski D , Chu J 
Published: March 2009

Abstract
In this paper a new plane-strain apparatus is described. The main feature of the plane-strain apparatus is that the intermediate principal stress can be measured by four submersible pressure transducers. Experimental data obtained from drained tests on very loose to medium dense sand are presented. The strength and deformation behavior of the sand under plane-strain conditions and shear band formation are studied. The results show that the failure envelope obtained from plane-strain tests is lower than that from triaxial tests. However, in terms of friction angle, the value obtained from plane-strain tests is higher than that from triaxial tests. The critical state line obtained under plane-strain conditions is also different from that under axisymmetric conditions. Under plane-strain conditions, shear bands occur for medium loose to dense specimens. However, no visible shear bands are observed for very loose specimens. This is consistent with the study reported by Han and Vardoulakis (1991) but different from that by Finno et al. (1996, 1997).
A New Setup for Measuring Go during Laboratory Compaction
Authors: Ismail MA , Rammah KI 
Published: March 2009

Abstract
Soil stabilization by compaction plays an important role in foundation engineering, both for construction and maintenance. Compaction specifications often require achievement of an in situ dry density (ρd) of 90–95% of the maximum value obtained from laboratory standard or modified Proctor test. However, ρd is not a design parameter per se; it is rather used to infer other parameters such as strength and stiffness through some empirical relationships. This paper describes a setup and procedure by which the small-strain (dynamic) shear stiffness can be measured accurately by propagating elastic shear wave through the stabilized material during laboratory compaction. The method enables measurement of the shear modulus [Go(ij)] in both horizontal and vertical planes. The ratio between Go in these two orthogonal planes (i.e., Ghh and Ghv) is a measure of the degree of stiffness anisotropy, and this could be used as input parameter in deformation calculations. The setup is designed so that it can be readily incorporated into the familiar Proctor test.
Interpreting Variable-head Tests Performed in Open Boreholes or Monitoring Wells with Several Screens
Authors: Chapuis RP 
Published: March 2009

AbstractVariable-head permeability tests can be performed in open boreholes or monitoring wells having either a long screen or several screened zones. In all cases, a test involves several layers composed of fractured rocks or pervious soils. In the hole or the pipe, the static water level represents some mean value of the hydraulic heads within the aquifer layers, a complex pattern of water circulation having been established within the open hole or the screened aquifers. This paper provides first the equation relating the static water level to the hydraulic and geometric parameters of the aquifers, and then the extended theory for variable-head tests under such conditions. According to theory and numerical analyses, such tests should provide straight semi-log head responses and velocity graphs. In real conditions, however, as shown by a series of field tests performed in a monitoring well equipped with three screens, broken line velocity graphs may be obtained. Such piecewise linear lines indicate that the product “hydraulic conductivity × shape factor” varies during the test within one or several aquifer layers. These variations can be related to internal erosion, which happens close to a screen when the gradient and seepage forces change direction during testing. This is confirmed by numerical modeling.
Application of Soil Stiffness Gauge in Assessing Small-Strain Stiffness of Sand with Different Fabrics and Densities
Authors: Sawangsuriya A , Bosscher PJ , Edil TB 
Published: March 2009

Abstract
The soil stiffness gauge (SSG) exhibits particular promise for determining the in situ soil stiffness at small strains. Because the SSG is new, its application in laboratory stiffness measurements is limited. The use of the SSG in assessing small-strain stiffness of sand with different fabrics, densities, and specimen sizes is presented herein. Two types of test containers were utilized and the results indicate that the SSG stiffness obtained from both containers show a similar trend but are offset by a constant value, which might be due to the effect of specimen dimensions and boundary configurations. A comparison with other small-strain stiffness tests indicates that the Young's moduli obtained from the seismic tests are consistently higher than those from the SSG tests. The plots of shear modulus versus shear strain amplitude suggest that the SSG modulus appears to be corresponding to a strain amplitude level higher than the strain amplitude of the seismic test, even though the SSG induces a strain amplitude comparable to that of seismic tests. Nonetheless, the SSG is found to be a potential and useful device for assessing the stiffness of sand with different fabrics and densities.
Validation and Calibration of a Laboratory Experimental Setup for Cross-Well Radar in Sand
Authors: Farid M , Alshawabkeh AN , Rappaport CM 
Published: March 2009

Abstract
Cross-well radar (CWR) uses electromagnetic wave antennas lowered into sampling wells, to image the dielectric properties of soil and detect scattering objects such as contaminants (in this case, dense nonaqueous phase liquids (DNAPLs)). To better understand the physics of CWR in soils, it is necessary to experimentally evaluate the behavior of antennas and electromagnetic (EM) waves. A proto-type model of an infinite soil medium was experimentally simulated by constructing a pilot-scale facility, referred to as SoilBED. The most important issue in any experimental research is the repeatability, reproducibility, and reliability of the results. This paper evaluates different factors affecting experimental data collection in order to achieve the required specifications to collect reproducible and reliable data. Antenna depth and insertion problems, soil disturbance, and boundary condition effects were experimentally evaluated. Other (desired or undesired) transmission couplings were studied, and efforts were conducted to eliminate the undesired paths. The calibrated and validated setup can be and is used for different purposes other than DNAPL detection, such as soil and antenna characterization, theoretical simulation validation, and inverse scattering by various materials in dry or saturated soil backgrounds.
Determination of the Transitional Fines Content of Mixtures of Sand and Non-plastic Fines
Authors: Yang S , Lacasse S , Sandven R 
Published: March 2009

Abstract
Sand-silt mixtures show different behavior with different fines content. The transitional fines content (TFC) is a key parameter which can indicate if the soil behaves as a sand-dominated or as a fines-dominated material. The determination of the TFC for a sand-silt mixture and the possible ways of obtaining the TFC from index data and the triaxial test results are discussed in this study.
Nonlinear Curve-Fitting Procedures for Developing Soil-Water Characteristic Curves
Authors: Sreedeep S , Singh DN 
Published: March 2009

Abstract
Measurement of soil suction for developing soil-water characteristic curve, SWCC, is a laborious and time-consuming task. On the other hand, commercially available databases that employ empirical fitting functions or the estimation algorithms for establishing the SWCC are quite costly and hence, beyond the reach of many. In such a situation, application of two simple nonlinear curve-fitting procedures (viz., a spreadsheet based program, SBP, and Levenberg-Marquardt Algorithm, LMA) for developing the drying SWCC was investigated. The utility and efficiency of these fitting procedures have been demonstrated by comparing the results vis-à-vis those obtained from a dewpoint potentiameter, WP4, and a knowledge-based database, KBD. In addition to this, efforts were made to develop correlations between the parameters used in the SWCC fitting functions and the physical properties of the soil, which can be determined quite easily by conducting routine laboratory tests. It has been demonstrated that these correlations can be used very efficiently for indirect estimation of the SWCC of the fine-grained soil.
Quantitative Analysis by Secondary Ion Mass Spectrometry
Authors: Newbury DE 
Published: March 2009

Quantitative analysis by secondary ion mass spectrometry (SIMS) involves reduction of spectral intensities to compositional values by the use of either empirical sensitivity factors or a physical model of ion emission. Of the several physical models available, the local thermal equilibrium (LTE) model is the one most easily applied to the analysis of an arbitrary multielement specimen. The accuracy of SIMS analysis by both the LTE model and by sensitivity factors has been compared on a series of well-characterized glass samples.
Error factor histograms have been prepared for several hundred elemental determinations. For the LTE analysis, approximately 50 percent of the analyses fall within a factor of two of the accepted value, and 80 percent fall within a factor of five. For analysis with elemental sensitivity factors derived from the glasses, approximately 80 percent of the analyses lie within a factor of two and over 95 percent within a factor of five of known values. quantitative analysis materials thermodynamic equilibrium micro-analysis mass spectrometry.
Fracture Resistant Titanium-Aluminum Laminate
Authors: Throop JF , Fujczak RR 
Published: March 2009

In an exploratory program for the development of damage tolerant materials for aircraft and helicopter structures, it has been found that laminated panels composed of mill-annealed Ti-6A1-4V sheet and alclad 2024-T3 sheet provided unusual fatigue and fracture resistance. Lamination of these two materials by explosive bonding results in a damage-tolerant fatigue resistant laminate.
Notched-beam specimens were fatigue cycled in pure bending at 30 Hz. The value of stress intensity factor range for crack propagation rates of 2.54 × 10-9 m/cycle (10-7 in./cycle) or less appears to be about 17.5 MN/m3/2 (16 ksiin.) For values of ΔK less than 35 MN/m3/2 (32 ksiin.) the fatigue crack propagation rate measured in the laminate is smaller than that of either the aluminum alloy or the titanium alloy. Room temperature fracture toughness tests of fatigue precracked beams made of equal thickness layers of the two materials give values higher than those of the component alloys. An interlaminar shear strength of 99 MN/m2 (14.3 ksi) was measured.
While complete evaluation of this laminate will require extensive testing, the early indications are that the damage tolerance is superior to that of either of the component metals because of the energy absorbing capacity provided by the laminated construction. Crack growth is retarded by the ductile cladding which forms the welded interfaces, and impact energy is absorbed in deformation and delamination. Moreover, because of favorable residual stresses the laminate appears to have a higher threshold for fatigue crack propagation than either of the component metals. This permits a larger defect size to be sustained without fatigue crack propagation at a given stress level, or a higher stress level to be endured with a given defect size.
Low Temperature Fracture Behavior of a Ti-6A1-4V Alloy and Its Electron Beam Welds
Authors: Tobler RL 
Published: March 2009

The effects of electron beam welding on the fracture behavior of a recrystallization annealed, extra-low-interstitial Ti-6A1-4V alloy have been investigated at temperatures in the ambient-to-cryogenic range. Plane strain fracture toughness (KIc) and subcritical crack growth parameters were measured using compact specimens 10 to 25.4 mm thick. These parameters can be used to predict the safe operating lifetimes of cryogenic pressure vessels and other welded Ti-6A1-4V structures.
At intermediate stress intensity factors and within the data scatter for replicate tests, the growth rates of fatigue cracks sited in the fusion and heat-affected zones of electron beam weldments were temperature insensitive and nearly equivalent to rates for the base metal. However, electron beam welding introduced a zone of low fracture toughness at the heat-affected-zone/fusion-zone boundary. The KIc value for this boundary zone at liquid nitrogen temperature (76 K) was 51 MPa/m1/2, 16 percent lower than the base metal. The base metal fracture toughness increases between 4 and 295 K, with an abrupt transition to higher KIc values occurring at temperatures between 76 and 125 K. Static load cracking, temperature effects, and specimen orientation effects on the fracture behavior of this titanium alloy are central topics of discussion.
A Perturbation Solution for Interlaminar Stresses In Bidirectional Laminates
Authors: Hsu PW , Herakovich CT 
Published: March 2009

This paper considers a thin, elastic, bidirectional, symmetric composite laminate subjected to a uniform axial strain. All interlaminar stresses are determined by a 0th-order perturbation analysis of the governing equations. The method of solution considers the laminate to be composed of an interior region (removed from the free edge) and a boundary layer region. The interior region is analyzed by dropping terms related to powers of the thickness-to-width ratio h/b in the dimensionless elasticity equations. The boundary layer region is studied by introducing a stretching transformation to the governing equations. A uniform solution is then formed by satisfying Prandtl's matching principle of perturbation theory.
Results for a four-layer, bidirectional graphite-epoxy laminate are compared with existing finite difference results. It is shown that the perturbation analysis provides more insight into the stress distribution near the free edge.
Amelioration of Tunnelling Susceptible Soils in the Hunter Valley, New South Wales, by Modification of Clay Double-Layer Interactions
Authors: Elliott GL 
Published: March 2009

The resultant force between van der Waals attraction and net free energy of interacting clay double layers has been calculated for a typical tunnelling susceptible soil in the Hunter Valley, N. S. W., Australia. Double-layer theory accounts adequately for the instability of this soil and for its response to wetting.
Double-layer theory has been used to derive a sodium absorption ratio versus sum of cations stability diagram for this soil specimen. The slope of the line separating flocculation and dispersion approached seven.
The soil was prepared with sodium and calcium chloride salts at different concentrations at and around the threshold of flocculation as predicted by double-layer theory. Aggregate stability, dispersal index, and behavior in model dams confirmed the predicted behavior
Experiences in Identification and Treatment of Dispersive Clays in Mississippi Dams
Authors: Forsythe P 
Published: March 2009

Twenty floodwater retarding dams in Mississippi have been treated to protect them from failure due to tunnel erosion. All of these sites developed severe tunneling characteristics of dispersed soils because of extreme rains in 1973, causing rapid acceleration of the probably latent soil condition.
The Soil Conservation Service in Mississippi initiated a detailed sampling and testing program for every site, not only to design treatment, but also to provide a basis for followup evaluation of performance. All three laboratory tests—dispersion, pinhole, and chemical—correlated well. Field identificaton tests did not correlate as well to actual site conditions or laboratory tests. Field tests were crumb, ultraviolet light, and turbidity.
The primary treatment used was hydrated lime applied in a 15-in. blanket following reworking of the fill to eliminate tunnels. Lime applications varied from 0.5 to 3 percent. Two structures were treated with sand-gravel blanket.
The pH values for lime-treated soils stayed high following application, restricting root penetration and vegetative growth.
Laboratory data coupled with field testing and performance observations provide engineers with a unique opportunity for studies that will evaluate and improve identification and treatment of dispersive clays. Some comparisons are already available and are presented in this paper.
Protecting a Dispersive Soil Storage by Water Treatment
Authors: Grant K , Ingles OG , Lawrence IA , Sommerville PJ 
Published: March 2009

Construction of reservoirs and dams in areas with dispersive soil poses several major problems: safety of the retaining walls, safety of the containing slopes, erosion resistance on exposed surfaces, and quality of the storage water. Important aspects of some of these problems are discussed with particular reference to a major new city reservoir constructed recently by the Melbourne and Metropolitan Board of Works on Cardinia Creek, Victoria, Australia. This offstream reservoir stores high-quality, low-turbidity water brought by conduit from other major catchments.
Because there was a potential turbidity problem due to the dispersive nature of the reservoir soils, it was recommended that the ionic concentration of the water be increased by adding specific amounts of salts of calcium or a mixture of salts of calcium and sodium in specified proportions.
Raw gypsum (calcium sulphate dihydrate) was added to the water at the reservoir inlet. The result has been that the clay suspended in the water at the commencement of first filling flocculated and settled, as expected, so that the water is now clear and the whole storage appears to be performing satisfactorily in all respects.
A method for comparing the economic merit of soil versus water treatment is described.
Factors Influencing Dispersive Clays and Methods of Identification
Authors: Heinzen RT , Arulanandan K 
Published: March 2009

Recent laboratory studies of the erosive behavior of consolidated soils using the rotating cylinder apparatus showed that the stress required to initiate erosion is affected significantly by the amount and type of clay, pH, organic matter, temperature, water content, thixotropy, pore, and eroding fluid composition.
Using the concept of critical shear stress as measured using the rotating cylinder and the flume, a quantitative criteria for a dispersive clay system is defined as one with a critical shear stress, τc equals zero. Using this criterion, qualitative methods of predicting dispersive clays are examined. It is concluded that most of the qualitative tests used for the identification of dispersive clays suffer from the serious drawback of subjective identification criteria. Proper correlation of the results obtained from the qualitative tests for the condition of τc = 0 will provide a better basis for dispersive clay identification.
The potential use of “free swell test” as a predictive criterion is indicated.