bluuebunny/crossref_metadata_2025 huggingface dataset:
Innovative Technique for Inspection of Polyethylene Piping Base Material and Welds and Non-Metallic Pipe Repair
Authors: Stakenborghs Robert J.
Published: July 2008

An innovative apparatus and method have been developed that can volumetrically examine any dielectric material, including polyethylene piping and non-metallic pipe repairs. The method employs a first of a kind apparatus that is based on the application of microwave energy. Comprehensive laboratory testing of the method and apparatus has been completed including the inspection of many samples of polyethylene pipe welds and non-metallic pipe repairs. The specimens examined had different types of internal flaws that commonly occur in industrial application. The apparatus has been shown capable of detecting the presence of internal flaws, such as lack of fusion and inclusions in polyethylene pipe welds, thickness changes and voids in polyethylene pipe, delaminations and lack of adhesion at the substrate of a non-metallic pipe repair. Additionally, the method has been tested in field applications. This paper will describe the method and apparatus and provide examples of polyethylene pipe weld and non-metallic pipe repair examinations.
Residual Stress Measurement Within a Single Pass Groove Weld Specimen Utilising Neutron Diffraction and the Contour Method
Authors: Turski Mark , Edwards Lyndon , James Jon , Bouchard Peter J. , Smith Mike , Withers Philip J.
Published: July 2008

This paper describes the measurement of longitudinal residual stresses within a specially designed 200×180×25 mm single groove weld specimen. The purpose of these measurements was to quantify the residual stress field arising from a single stringer weld bead laid down within the constraint of a groove in order to validate finite element simulations of the welding process. Measurements were made over the cross section at the mid-bead length, utilising the relatively new Contour method and neutron diffraction. Non destructive neutron diffraction measurements were made using ENGIN-X, the engineering spectrometer at the ISIS facility of the Rutherford Appleton Laboratory (UK). The Contour method measurement was applied destructively at the Open University (UK), producing a detailed full-field residual stress map. Results from these measurements indicate a peak tensile longitudinal residual stress of ∼300 MPa within the parent material adjacent to the weld bead. Good agreement is found between both techniques.
The Development of Radiation Embrittlement Models for U.S. Power Reactor Pressure Vessel Steels
Authors: Wang J. A. , Rao N. S. V. , Konduri S.
Published: July 2008

The information fusion technique is used to develop radiation embrittlement prediction models for reactor pressure vessel (RPV) steels from U.S. power reactors, including boiling water reactors and pressurized water reactors. The Charpy transition temperature-shift data is used as the primary index of RPV radiation embrittlement in this study. Six parameters—Cu, Ni, P, neutron fluence, irradiation time, and irradiation temperature—are used in the embrittlement prediction models. The results indicate that this new embrittlement predictor achieved reductions of about 49.5% and 52% in the uncertainties for plate and weld data, respectively, for pressurized water reactor and boiling water reactor data, compared with the Nuclear Regulatory Commission Regulatory Guide 1.99, Rev. 2. The implications of dose-rate effect and irradiation temperature effects for the development of radiation embrittlement models are also discussed.
Finite Element Prediction of Residual Stress Distributions in a Multipass Welded Piping Branch Junction
Authors: Jiang Wei , Yahiaoui Kadda
Published: July 2008

Piping branch junctions and nozzle attachments to main pressure vessels are common engineering components used in the power, oil and gas, and shipbuilding industries amongst others. These components are usually fabricated by multipass welding. The latter process is known to induce residual stresses at the fabrication stage which can have severe adverse effects on the in-service behavior of such critical components. It is thus desirable if the distributions of residual stresses can be predicted well in advance of welding execution. This paper presents a comprehensive study of three dimensional residual stress distributions in a stainless steel tee branch junction during a multipass welding process. A full 3D thermo-mechanical finite element model has been developed for this purpose. A newly developed meshing technique has been used to model the complex intersection areas of the welded junction with all hexahedral elements. Element removal/reactivate technique has been employed to simulate the deposition of filler material. Material, geometry and boundary nonlinearities associated with welding were all taken into account. The analysis results are presented in the form of stress distributions circumferentially along the weldline on both run and branch pipes as well as at the run and branch cross sections. In general, this computational model is capable of predicting 3D through thickness welding residual stress, which can be valuable for structural integrity assessments of complex welded geometries.
A Study on the Creep Rupture Life Estimation of Internally Pressurized Welded Pipe Joints
Authors: Teramae Tetsuo
Published: July 2008

A study had been conducted to establish the precise method estimating the creep rupture life of welded steam pipe joints used for thermal power plants. Firstly, basic creep data of 2.25CrlMo low alloy steel, such as rupture time, minimum creep strain rate, and creep crack growth rate, had been obtained on mother material, fine-grained heat affected zone (HAZ), coarse-grained HAZ, and weld metal. Secondly, internally pressurized creep rupture test had been conducted on the pipe specimens of mother material, seam welded joint and girth welded joint. Whereas girth welded pipe joints showed longer lives than those of mother material pipes, seam welded pipe joints showed shorter rupture lives. To clarify the effect of fine-grained HAZ on the rupture life of the seam welded pipe joint, an analytical study had been performed taking the difference of creep deformation between fine-grained HAZ and mother material into account. The analytical creep rupture life had agreed quite well with experimental one. Finally, internally pressurized creep rupture test had been conducted on the specimens of the seam welded pipe joints with a semi-elliptical notch introduced along the outer HAZ of weld line. Creep rupture life of these specimens was calculated as the sum of crack incubation time and crack growth time. It was shown that the calculated creep rupture life had agreed quite well with the experimental result.
Crack Growth Analysis for a Cylindrical Shell Under Dynamic Loading
Authors: Mirzaei Majid , Karimi Reza
Published: July 2008

A cylindrical tube subjected to internal detonation experiences a traveling load that produces transient deformations. The resulting flexural waves in the tube wall can lead to high strains, which substantially exceed the equivalent static strains. This paper reports the growth analysis of a preexisting crack in a thin cylindrical tube using the finite element method. The numerical modeling of the structural response of the tube to detonation loading was performed using WARP3D, which is a nonlinear-dynamic software for crack modeling using FEM. The simulations were compared with experimental results from literature and also with the results obtained from an analytical model for elasto-dynamic response of cylindrical shells with finite length to internal detonation loading. The modeling of crack growth was also performed using WARP3D based on CTOA as the fracture parameter. The final part of the paper is devoted to comparisons between the numerical crack growth simulations and experimental results reported in the literature.
Experimental Research and Application of UT Inspection Method for Detection of Defects on Pressure Vessels and Pipelines Under High-Temperature Environment
Authors: Guan Weihe , Yan Changzhou , Tao Yuanhong , Chen Xuedong
Published: July 2008

High temperature UT inspection techniques can be used to conduct random inspection on line on the key locations of pressure vessels and pipelines in operation so as to find out fresh defects in time and determine inspection time. It can also be used for real-time monitoring and control of defect-containing pressure vessels and pipelines and provide a basis for safety assessment of equipment so as to ensure safe operation of pressure vessels and pipelines. The propagation velocity of ultrasonic wave in metallic pressure-bearing equipment and its amplitude vary with temperature, therefore, the factors that influence UT inspection ability and measuring accuracy will be increased. In this paper the variation in sound velocity and attenuation law of ultrasonic shear wave in common pressure vessels and pipelines in the range of room temperature ∼ 450 °C is studied, the sound velocity decreases linearly as temperature rises and the attenuation coefficient α decreases as temperature rises, from 0.006 dB/mm at room temperature to 0.08dB/mm at 450 °C. The factors that influence inspection accuracy of ultrasonic shear wave are discussed, including variation in sound velocity, loss in interface sound pressure, thermal expansion, and so forth. The method for detection of weld defects within above temperature range using the ultrasonic shear wave is established, including scanning manner, measurement of defect height and length and their position correction, and so forth. The present situation of online high-temperature UT inspection technology for pressure vessels and pipelines in China is summarized through online UT inspection examples of petrochemical equipment under local high-temperature environment.
A Stress Analysis Method for Cylindrical Shells With Nozzles Subjected to Internal Pressure, External Forces and Moments
Authors: Xue Ming-De , Du Qing-Hai , Li Dong-Feng , Hwang Keh-Chih
Published: July 2008

An identical stress analysis method based on the thin shell theory is carried out for cylindrical shells with normally intersecting nozzles subjected to internal pressure and six kinds of external branch pipe loads involving axial tension, two kinds of transverse shear forces, longitudinal and circumferential bending and torsion moments. The thin shell theoretical solution is obtained based on the Morley equation instead of the Donnell shallow shell equation. The accurate continuity conditions at the intersecting curve, which is a complicated space curve, are adopted. The presented results are verified by three-dimensional finite element method (FEM). The theoretical solution can be applied to d/D ≤ 0.8, λ = d/DT ≤ 12 and d/D ≤ t/T ≤ 2 successfully. The solutions are in good agreement with WRC Bulletin 297 when diameter ratio is small. In the paper some typical design curves calculated by the theoretical solutions are presented and their applicable ranges are greatly expanded in comparison with current design methods.
Study on Corrosion Behavior of AISI316L and SAF2205 Stainless Steels in Acetic Acid Solution Containing Br-Ion
Authors: Liang Bin , Gong Jianming , Tu Shantung , Jiang Yong
Published: July 2008

Petrochemical equipments made of austenitic stainless steel are often used in the environment of acetic acid solution. Premature corrosion failure led by acetic acid solution containing Cl− or Br− occurs in service. In the present paper, corrosion behavior of AISI316L austenitic stainless steel and SAF2205 duplex stainless steel in acetic acid solution containing Br-ion was studied by measuring the corrosion weight loss and Potentiodynamic anodic polarization curve. Effects of temperature and Br− concentration on the corrosion behaviors of AISI316L and SAF2205 material were investigated. The research results show that the corrosion rate markedly increases and pitting potential rapidly decreases with increasing temperature and Br− ion concentration. The pitting resistance of SAF2205 stainless steels is superior to AISI316L. For sensitized AISI316L and SAF2205 stainless steels, the similar rules were founded with increasing Br− concentration; sensitizing treatment will lead to decrease in corrosion resistance. Pitting induced by Br ion preferentially occurred at austenitic boundaries for sensitized AISI316L stainless steels, whereas pitting preferentially occurred at austenitic boundaries, ferrite-austenite boundaries and ferrite boundaries for sensitized SAF2205 duplex stainless steels.
Numerical Analysis of Thermal Deformation and Residual Stress for the Brazed Plate-Fin Structure
Authors: Chen Hu , Gong Jianming , Geng Luyang , Tu Shan-Tung
Published: July 2008

Compared to traditional shell-and-tube exchangers with the same material, compact plate-fin heat exchangers (PFHE) made of brazed stainless steel have superior heat transfer capability, less volume, lighter weight and low cost. Therefore it has been widely used in many industries, such as air separation, petrochemical, aerospace, energy etc. and PFHE has been the typical candidate to realize the miniaturization of heat exchanging equipments, which are the enabling technology for the miniaturization of chemical and thermal systems. It is negligible that residual stresses and thermal distortion under the effect of thermal cycle, self-constraint and clamping pressure load during brazing for the brazed plate-fin structure that has the millimeter-level function cell. This paper presents a thermo-mechanical finite element analysis for determining the deformation and residual stress of multi-layers stainless steel AISI 304 plate-fin structure, which are counter-flow and brazed with amorphous nickel-base filler metal BNi-2, based on the actual brazing process. The feature of deformation and residual stresses distribution are reported and the effect of 3 factors including the number of layers, brazing temperature, clamping pressure loads on the residual stresses and the distortion are investigated respectively.
Expert System for Integrity Assessment of Piping Containing Defects
Authors: Lin Y. C.
Published: July 2008

The mechanical integrity of in-service pressure piping is a matter of great importance for both economical and safety reasons. Considering the uncertainties in various internal operating loadings and external forces, flaw sizes, material properties, this paper presents a probabilistic assessment methodology for in-service pressure piping containing defects, which is especially designed for programming. A general sampling computation method of the stress intensity factor (SIF), in the form of the relationship between SIF and axial force, bending moment and torsion, is adopted in the probabilistic analysis methodology. Based on the European flaw assessment procedure, SINTAP, Integrity Assessment Expert System of In-service Pressure Piping Containing Flaws (IAESPP-SINTAP) is developed using the presented probabilistic methodology. A numerical example is given to show the application of IAESPP-SINTAP software. The failure probabilities of every defect and the whole piping can be obtained by using this software.
Computer Simulation of Rupture Disc Design
Authors: Murty D. V. R. , Rao Y. Bhaskar
Published: July 2008

The design of rupture discs has been traditionally done by means of experimentation. With the advent of computers many of the critical components of Engineering have been successfully analysed by means of Finite Element Analysis. An attempt has been made here to analyse rupture discs using FEA and compare the results. The analysis has been done using SDRC IDEAS and ANSYS packages and compared the results with the experimental results previously published.
Initiation and Arrest of Delayed Hydride Cracking in Zr-2.5Nb Tubes
Authors: Kim Young S. , Ahn Sang B. , Cheong Yong M.
Published: July 2008

Using Kim’s delayed hydride cracking (DHC) model, this study reanalyzes the critical temperatures for DHC initiation and arrest in Zr-2.5Nb tubes that had previously been investigated with Dutton and Puls’s DHC model. At temperatures over 180 °C along with a hydrogen concentration of over 15 ppm H, the DHC initiation in a CANDU Zr-2.5Nb tube was suppressed, which required a cooling or ΔT from the terminal solid solubility for dissolution (TSSD) temperatures. With the number of the thermal cycle increasing, the DHC initiation temperatures or Tcs gradually shifted towards the TSSD. At a hydrogen concentration as low as 7 ppm H and temperatures lower than 180 °C, a DHC initiation occurred at temperatures near the TSSD with little ΔT. Different DHC initiation temperatures with hydrogen concentrations are discussed in view of precipitation of hydrides in the zirconium matrix either by a cooling or by a stress-induced γ- to δ-hydride transformation. The DHC arrest temperatures were governed by the critical supersaturated hydrogen concentration or ΔC regardless of the thermal cycle treatment. By correlating the DHC cracking and arrest temperatures with the supersaturated hydrogen concentration or ΔC for the DHC cracking and arrest, we conclude that the ΔC arising from the hysteresis of the terminal solid solubility of hydrogen on a heat-up and on a cool-down is the driving force for the DHC.
Modified Rate Approach Method to Evaluate Fatigue Life of Carbon Steel Under Simulated Synchronously Changing BWR Conditions
Authors: Hirano Akihiko , Sakaguchi Katsumi
Published: July 2008

The fatigue life of carbon steel is influenced by Boiling Water Reactor (BWR) conditions such as water temperature, dissolved oxygen concentration, water flow rate and so on. These parameters changes constantly during the operation of BWR plants and strain rate changes in the structural components occur because of temperature changes. In general, fatigue life evaluation equations have been formulated based on fatigue data obtained under constant conditions. Before using these equations to evaluate the fatigue life of actual components, a study is necessary to make sure they are applicable to changing conditions. In this study, fatigue tests were performed under changing strain amplitude, strain rate, temperature, dissolved oxygen content, and water flow rate conditions. It was confirmed that the proposed fatigue life equation could predict the fatigue life under practical changing conditions.
AnO-Phosphotransferase Catalyzes Phosphorylation of Hygromycin A in the Antibiotic-Producing OrganismStreptomyces hygroscopicus
Authors: Dhote Vidya , Gupta Shuchi , Reynolds Kevin A.
Published: July 2008

The antibiotic hygromycin A (HA) binds to the 50S ribosomal subunit and inhibits protein synthesis in gram-positive and gram-negative bacteria. The HA biosynthetic gene cluster inStreptomyces hygroscopicusNRRL 2388 contains 29 open reading frames, which have been assigned putative roles in biosynthesis, pathway regulation, and self-resistance. Thehyg21gene encodes anO-phosphotransferase with a proposed role in self-resistance. We observed that insertional inactivation ofhyg21inS. hygroscopicusleads to a greater than 90% decrease in HA production. The wild type and thehyg21mutant were comparably resistant to HA. UsingEscherichia colias a heterologous host, we expressed and purified Hyg21. Kinetic analyses revealed that the recombinant protein catalyzes phosphorylation of HA (Km= 30 ± 4 μM) at the C-2‴ position of the fucofuranose ring in the presence of ATP (Km= 200 ± 20 μM) or GTP (Km= 350 ± 60 μM) with akcatof 2.2 ± 0.1 min−1. The phosphorylated HA is inactive against HA-sensitive ΔtolC E. coliandStreptomyces lividans. Hyg21 also phosphorylates methoxyhygromycin A and desmethylenehygromycin A withkcatandKmvalues similar to those observed with HA. Phosphorylation of the naturally occurring isomers of 5‴-dihydrohygromycin A and 5‴-dihydromethoxyhygromycin A was about 12 times slower than for the corresponding non-natural isomers. These studies demonstrate that Hyg21 is anO-phosphotransferase with broad substrate specificity, tolerating changes in the aminocyclitol moiety more than in the fucofuranose moiety, and that phosphorylation by Hyg21 is one of several possible mechanisms of self-resistance inS. hygroscopicusNRRL 2388.
Mycoplasma pneumoniae
Infection and Environmental Tobacco Smoke Inhibit Lung Glutathione Adaptive Responses and Increase Oxidative Stress
Authors: Kariya Chirag , Chu Hong Wei , Huang Jie , Leitner Heather , Martin Richard J. , Day Brian J.
Published: July 2008

Chronic cigarette smoking evokes a lung glutathione (GSH) adaptive response that results in elevated GSH levels in the lung epithelial lining fluid (ELF). Currently, little is known about how the lung regulates or maintains steady-state levels of ELF GSH. Pathogens such as
Mycoplasma pneumoniae
can exacerbate airway inflammation and oxidative stress. The present study examined whether
M. pneumoniae
infections synergize with environmental tobacco smoke (ETS) to disrupt lung GSH adaptive responses. Mice were exposed separately and in combination to ETS and
M. pneumoniae
for 16 weeks. ETS exposure resulted in a doubling of ELF GSH levels, which was blocked in the
M. pneumoniae
-exposed mice. In addition, the ETS-plus-
M. pneumoniae
-exposed mice had elevated levels of oxidized glutathione (GSSG), resulting in a dramatic change in the ELF redox state that corresponded with an increase in lung tissue DNA oxidation. Similar findings were observed in human lung epithelial cells in vitro. Cells exposed separately or in combination to cigarette smoke extract and
M. pneumoniae
for 48 h had elevated apical levels of GSH compared to control cells, and these increases were blocked by
M. pneumoniae
and were also associated with increased cellular DNA oxidation. Further studies showed that
M. pneumoniae
exposure blocked ETS-induced increases in GSH reductase, an enzyme that recycles GSSG back to GSH, both in vitro and in vivo. These studies suggest that
M. pneumoniae
infection synergizes with ETS and suppresses the lung's ability to respond appropriately to environmental challenges leading to enhanced oxidative stress.
PneumococcalHaemophilus influenzaeProtein D Conjugate Vaccine Induces Antibodies That Inhibit Glycerophosphodiester Phosphodiesterase Activity of Protein D
Authors: Toropainen Maija , Raitolehto Anna , Henckaerts Isabelle , Wauters Dominique , Poolman Jan , Lestrate Pascal , Käyhty Helena
Published: July 2008

Haemophilus influenzaeouter membrane protein D (PD) is a glycerophosphodiester phosphodiesterase (GlpQ) activity-possessing virulence factor and a promising vaccine antigen, providing 35.3% efficacy against acute otitis media caused by nontypeableH. influenzae(NTHI) when it was used as a carrier protein in a novel pneumococcal PD conjugate (Pnc-PD) vaccine. To study if PD-induced protection against NTHI could be due to antibodies that inhibit or neutralize its enzymatic activity, a GlpQ enzyme inhibition assay was developed, and serum samples collected from Finnish infants before and after Pnc-PD vaccination were analyzed for enzyme inhibition and anti-PD immunoglobulin G (IgG) antibody concentration. Before vaccination at age 2 months, the majority (84%) of infants (n= 69) had no detectable anti-PD IgG antibodies, and all were enzyme inhibition assay negative (inhibition index, <20). At age 13 to 16 months, all infants receiving three or four doses of Pnc-PD had detectable anti-PD IgG antibodies and 36% (8/22 infants) of the infants receiving three doses and 26% (6/23 infants) of the infants receiving four doses of Pnc-PD were inhibition assay positive (inhibition index, ≥20). No significant rise in anti-PD IgG antibodies or enzyme inhibition among control vaccinees (n= 24) receiving three doses of hepatitis B vaccine was detected. A modest correlation (rs, ∼0.66) between anti-PD IgG concentration and enzyme inhibition was detected; however, their kinetics were clearly different. These data suggest that measurement of antibody responses that inhibit PD's enzymatic activity could be a useful tool for assessing Pnc-PD vaccine-induced protective immunity against NTHI.
Host Biomarkers and Biological Pathways That Are Associated with the Expression of Experimental Cerebral Malaria in Mice
Authors: Oakley Miranda S. , McCutchan Thomas F. , Anantharaman Vivek , Ward Jerrold M. , Faucette Laurence , Erexson Cindy , Mahajan Babita , Zheng Hong , Majam Victoria , Aravind L. , Kumar Sanjai
Published: July 2008

Cerebral malaria (CM) is a primary cause of malaria-associated deaths among young African children. Yet no diagnostic tools are available that could be used to predict which of the children infected withPlasmodium falciparummalaria will progress to CM. We used thePlasmodium bergheiANKA murine model of experimental cerebral malaria (ECM) and high-density oligonucleotide microarray analyses to identify host molecules that are strongly associated with the clinical symptoms of ECM. Comparative expression analyses were performed with C57BL/6 mice, which have an ECM-susceptible phenotype, and with mice that have ECM-resistant phenotypes: CD8 knockout and perforin knockout mice on the C57BL/6 background and BALB/c mice. These analyses allowed the identification of more than 200 host molecules (a majority of which had not been identified previously) with altered expression patterns in the brain that are strongly associated with the manifestation of ECM. Among these host molecules, brain samples from mice with ECM expressed significantly higher levels of p21, metallothionein, and hemoglobin α1 proteins by Western blot analysis than mice unaffected by ECM, suggesting the possible utility of these molecules as prognostic biomarkers of CM in humans. We suggest that the higher expression of hemoglobin α1 in the brain may be associated with ECM and could be a source of excess heme, a molecule that is considered to trigger the pathogenesis of CM. Our studies greatly enhance the repertoire of host molecules for use as diagnostics and novel therapeutics in CM.
Prediction of Undrained Movements Caused by Embankments on Muskeg
Authors: Hollingshead Garry W. , Raymond Gerald P.
Published: July 2008

Consideration is given to the prediction of undrained movements which may occur due to contained yielding beneath embankments on muskegs. The study shows that insignificant improvement in the predicted undrained movements can be expected by assuming the soil to be an elastic cross-anisotropic material unless the independent shear modulus is measured. All predictions were made using the finite element technique and assuming the soil to be an elastic isotropic yielding material. The settlement predictions are in good agreement with the recorded construction movements of the two case records studied.The first analysis clearly shows that the yielded zone is restricted to a soft clay layer immediately beneath about 20 ft (6.1 m) of peat and marl. The predictions show that berms have a beneficial effect in containing this zone and reducing differential settlement. Horizontal movements are significant in comparison with the vertical movements except near the centerline.In the second case, analysis of a shallow peat layer underlain by stiff clay shows that the predicted settlement and shape of yield zone are largely dependent on whether the lower boundary is assumed perfectly rough or shearless.
Classification of river and lake ice
Authors: Michel B. , Ramseier R. O.
Published: July 2008

There is no classification of river and lake ice that simultaneously takes into account the history of ice formation, the structure of the ice cover, and the texture of the various ice types. Such fundamental information is a prerequisite to the determination and discussion of their physical and mechanical properties.The first part of this classification is a brief description of the formation and the physical properties of the three important ice layers making up the ice cover. The second aspect of the classification deals with the texture of various ice types.It is possible to determine certain meteorological conditions which have occurred during formation of primary ice from on-site observations and the study of ice profiles. Hydrodynamic information can be obtained from the study of secondary or superimposed ice. Presently, major events causing layers of frazil slush, congealed frazil slush, and drained snow ice can easily be recognized and interpreted.The evaluation and eventual prediction of the mechanical properties of the various ice types according to such a classification will be helpful in solving engineering and navigation problems.
The Vane Test in Organic Soils
Authors: Northwood R. P. , Sangrey D. A.
Published: July 2008

In situ vane tests were carried out in a number of different muskeg deposits to examine the mechanism of failure and the effect of variation in vane size and speed of testing. The failure mechanism in peat was found to be similar to that in soft clays. The apparent shear strength varied with vane size but was independent of testing speed. There was an optimum vane size of 10 cm diameter.Block samples were obtained from one site for laboratory vane tests to investigate anisotropy in the strength of the peat. In situ tests for anisotropy using vanes of varying shape confirmed the laboratory results, and showed that strengths on the vertical plane could be 100 % higher than those on the horizontal plane.
The Empress Hotel, Victoria, British Columbia. Sixty-Five Years of Foundation Settlements
Authors: Crawford C. B. , Sutherland J. G.
Published: July 2008

Construction of the Empress Hotel began in 1904 on a site reclaimed from the sea. The combined load of the fill and the structure has caused several feet of compression in the underlying marine silty clay. Fortunately, settlement observations have been made regularly since1912 and the nature of the foundations and the structure allow reliable extrapolation back to the first loading. This paper describes the site, the applied loading, the settlements observed, and the results of laboratory tests on samples recently obtained. The observed primary and secondary consolidation settlements are compared with computed values.
Bearing Capacity of Piles Driven into Rock
Authors: Rehnman Sven–Erik , Broms Bengt B.
Published: July 2008

An experimental study is presented on the point bearing capacity of piles in rock. The bearing capacity for granite, limestone, and sandstone was found to be approximately four to six times the unconfined compressive strength of the rock material when the load was applied perpendicular to the rock surface. The ultimate bearing capacity was affected by the inclination of the applied load and by the penetration depth. The ultimate strength decreased rapidly when the inclination exceeded 45°. The strength increased with increasing penetration depth. The increase for granite and sandstone was 25 to 50% when the depth increased from 0 to 1.0 times the point diameter. The corresponding increase for limestone was 60 to 70%.The point bearing capacity was calculated by the Coulomb–Mohr and by the Griffith failure theories. The test results indicated that the effect of the inclination of the rock surface and of the penetration depth for granite and sandstone was less than calculated. Satisfactory agreement was found for the limestone between measured and calculated values. Comparisons with the Griffith failure theory indicated that the measured failure loads were approximately twice the calculated failure loads.
Electronic Measurement of Changes in the Volume of Pore Water During Testing of Soil Samples
Authors: Mitchell R. J. , Burn K. N.
Published: July 2008

Two systems are described for electronic recording of changes in the volume of pore water for triaxial testing of soils: one using a miniature force transducer to measure by direct weighing; the other based upon a float system connected to the core of a differential transformer. Both systems provide measurement of volume change at least as accurately as may be obtained by visual reading of burettes graduated to 0.1 cm3, i.e. to ± 0.05 cm3.
Lightpiers on Friction Piles in Deep Soft Marine Clay
Authors: Danys J. V.
Published: July 2008

The deposit of marine clays in Lake St. Peter, Quebec, is as much as 300 ft (91 m) deep. Construction of lightpiers was started shortly after the turn of the century but settlement, tilting, and even failures of the structures occurred and construction of the new piers was not continued. As the navigation season is being extended into winter, the need for lightpiers becomes greater. Apart from the sensitive and very compressible clays, the heavy ice forces made a design very difficult. Introducing novel design features and applying the present knowledge of soil mechanics, two piers were designed and built in 1966 on 157 friction piles each, and two more in 1969. An advance field test of piles in situ was impractical as the structures were in the middle of the lake. Extensive boring and laboratory testing program preceded construction, and the shear strength data of the clay was used for the pile foundation design. Field pile testing confirmed the design assumptions.
South Nation River Landslide, 16 May 1971
Authors: Eden W. J. , Fletcher E. B. , Mitchell R. J.
Published: July 2008

This brief account lists the dimensions, and the soil and climatic conditions concerned in a large landslide which occurred along the South Nation River in Eastern Ontario.
One-dimensional Consolidation of Thawing Soils
Authors: Morgenstern N. R. , Nixon J. F.
Published: July 2008

The physics of consolidation of a thawing soil is formulated in terms of the well-known theories of heat conduction and of linear consolidation of a compressible soil. A moving boundary problem results, and closed form solutions have been obtained for several cases of practical interest. The results are presented in terms of normalized pore pressure distributions. It is shown that the excess pore pressures and the degree of consolidation in thawing soils depend primarily on the thaw consolidation ratio.
Effect of End Restraint on High Pressure Tests of Granular Materials
Authors: Roy M. , Lo K. Y.
Published: July 2008

Comparative drained triaxial tests at high confining pressures were carried out on a strong- and weak-grained granular material with 'rough' and 'lubricated' ends. The results indicated that the stress-strain relationships are significantly influenced by the end conditions. The use of 'lubricated' ends for high pressure tests results in much more uniform distribution of stress, strain, volume change, and crushing of particles throughout the samples.
Hydrodynamic Response — or Slug Tests as a Means to Monitor the Progress of Well Development
Authors: Vonhof J. A.
Published: July 2008

Sequential hydrodynamic response—or slug tests in a well during well development—provide an easy method for objective measurement of well development and comparison of the various development techniques that may be employed. Slug-test equipment developed in Saskatchewan permits precise continuous recording of changing water levels for all times except the first few seconds after the introduction of the slug into the well. Three examples of slug-test analysis indicate jetting and air development to be the most successful techniques for well development in a sand aquifer in southeastern Saskatchewan; mechanical surging, on the other hand, actually reversed the development process in the aquifer. The substitution of a bentonite mud for clear water in drilling out the completion zone in one well proved to be highly undesirable because considerably more effort and time were required to develop this well.
Geotechnical Properties of Nearshore Sediments of Canso Strait, Nova Scotia
Authors: Brown J. D. , Rashid M. A.
Published: July 2008

The results are reported of a field and laboratory investigation of the geotechnical properties of the surficial bottom, or near-surface, sediments of the Strait of Canso, Nova Scotia. The investigation procedures included in situ shear vane tests performed using a diver-operated apparatus lowered to the bottom from the survey ship, and undisturbed sampling using the Lehigh University Gravity Corer, which provides a 10 cm diameter sample.Soils encountered within the sampling depth (0–1.5 m maximum) consisted of layered and bioturbated coarse-grained and fine-grained sediments. Most of the investigative work was concerned with the fine-grained sediments, clayey silts, and clays, which were found to be soft and compressible, but possessed a reserve resistance in both shear and one-dimensional consolidation which give them the characteristics of overconsolidated clays. This reserve resistance has been attributed to chemical alteration, including the effects of organic compounds.
The Behavior of Drammen Plastic Clay under Low Effective Stresses
Authors: Iyer T. S. Ramanatha
Published: July 2008

Shear tests on undisturbed samples of clay at low normal effective stresses have proved to be useful in order to understand the actual nature of cohesion. Drammen plastic clay was considered to be a suitable material for this study as it is nonfissured and noncemented. Triaxial compression and extension tests without membranes were performed on this clay in the low stress range. The samples in compression failed along inclined planes, while those in extension failed nearly along a horizontal plane. It was found that the shear resistance in the case of extension tests was independent of the average effective normal stress in the low stress range. The magnitude of the cohesion was nearly the same as the cohesion observed in compression tests. The reasons for these differences are discussed in terms of a proposed model. The shear resistance in extension tests is probably a structural cohesion and no friction seems to be mobilized under these conditions. When the samples were reconsolidated to in situ stresses, the shear parameters in extension tests were the same as in compression tests. It is, therefore, suggested that mobilization of friction depends on the nature of the contacts which undergo modification when disturbance of structure on account of reconsolidation takes place.
A Neutron Radiographic in vitro Examination of Soils
Authors: Wilson N. E. , Harms A. A. , Emery J. J.
Published: July 2008

A preliminary investigation has been conducted to explore the potential utilization of neutron radiography for the in vitro examination of soils contained within sampling tubes. Radiographic images obtained by such means have been found to provide indications of changes in soil type and details of soil structure which are distinct from images obtained by conventional X-ray radiographic means.
Effect of Water Sorption on Carbonate Rock Expansivity
Authors: Hudec Peter P. , Sitar Nicholas
Published: July 2008

Length change experiments on carbonate rock samples indicate that the thermal coefficient of expansion (contraction) from normal room temperature to below freezing is a function of the sorptive characteristic of the rock. The highly adsorptive rocks, i.e. those adsorbing more than 40% of their water from near 100% humidity atmosphere, show an increased thermal contraction coefficient in the saturated state over their dry state. The low adsorptive rocks have the same thermal expansion coefficients either in a dry or saturated state.The highly adsorptive rocks expand isothermally upon saturation. The average isothermal expansion of a group of nine rocks was equivalent to the dry thermal expansion of a 78 °C temperature change. The low adsorptive rocks showed a small net isothermal contraction upon wetting.The results indicate that the thermal coefficients of expansion obtained below the 100 °C range must specify the saturation conditions of the rock, and may differ for dry and saturated rock. A mechanism of weathering of highly adsorptive rocks is suggested, based on isothermal expansion and contraction of these rocks in dry and saturated states respectively. If confined, as in concrete, such rocks may generate destructive expansive forces upon wetting.
The Effect of Penetration Rate on the Strength of Remolded Clay and Sand Samples
Authors: Dayal Umesh , Allen John H.
Published: July 2008

The penetration rate effect on the strength of clay and sand was studied by constant velocity penetration tests performed with various velocities up to 2.662 f.p.s. (81.14 cm/s). The clay and sand targets were of various strengths and moisture contents. The construction of the penetrometer is similar to that used in static tests, and in each test the cone resistance, sleeve friction, and penetration velocity were recorded.Experimental results indicated that for granular soils the effects of penetration velocity on cone and sleeve friction resistances are insignificant, whereas, for cohesive soils, the increase in penetration velocity causes an increase in the cone and friction resistances. It is found that for the cohesive soils the ratio of dynamic to static strength is directly proportional to the logarithm of the penetration velocity ratio. The proportionality constant of this relationship defined as soil viscosity coefficient depends on the physical properties of the soil and the soil strength and its value increases as the strength of the soil decreases. For the tested soils various values of the soil viscosity coefficient are proposed for different strength ranges. The validity of the analytical relationship is established for penetration velocities ranging from 0.0044 f.p.s. (0.13 cm/s) to 18 f.p.s. (550 cm/s).
Experimental Study of Edge Loading of Ice Plates
Authors: Frederking R. , Gold L. W.
Published: July 2008

The interaction of an ice cover and a fixed narrow structure was modelled by edge loading large rectangular (0.4 m × 0.5 m) plates of columnar-grained ice. The plates were set on one of the long edges and the load was applied to the opposite edge by means of indentors of widths varying between 12 and 150 mm. Ice plates 25 to 100 mm thick were used. Observations were made of the dependence of the indentation load on indentor width and ice thickness. All loading was within the range of ductile behavior of the ice. The study indicated that the indentation pressure was a function of the width of the indentor, but not of the thickness of the ice plate. The mode of deformation was observed to be primarily two dimensional. The results of this study are in contrast to observations under field conditions, from which it is concluded that the indentation pressure depends on the ratio of the width of the indentor to the thickness of the ice cover. This suggests the presence of an effect which must be given attention in the development of modelling techniques for the ice pressure problem.
Groundwater Exploration in Pleistocene Deposits at Landis, Saskatchewan, Canada
Authors: Sauer E. Karl , Beckie V. G.
Published: July 2008

A groundwater supply of 600 imperial gallons per minute (27301/min) was required at Landis, Saskatchewan, for development of an underground gas storage cavern with 1.19 × 106 barrel capacity. The cavern was to be developed by dissolving and removing the salts of the Middle Devonian Prairie Evaporite Formation the top of which is 3940 ft (1201 m) below ground surface. It was found that the most productive aquifers were in the glacial drift. Three intertill aquifers were identified. The presence of four till stratigraphic units was used as a basis for the interpretation of the groundwater hydrology. Three pumpwells were completed. Tests and analyses include aquifer coefficients such as transmissivity, storage coefficients, vertical permeability, and estimates of safe yields. A monitoring system was also established to measure the effect of high production on local domestic wells. This project demonstrated the value of establishing a formal stratigraphic system for interpretation of aquifer properties in glacial deposits.
A Note on Friction Ratio
Authors: Dayal Umesh , Allen J. H.
Published: July 2008

Constant velocity penetration tests were conducted on the different types of soils ranging from gravelly sand through clay of various strengths and moisture contents. The tests were performed for various penetration velocities up to a maximum of 2.66 f.p.s. (81.14 cm/s). From the measured cone pressure and local side friction (sleeve friction), the friction ratio is calculated at various penetration velocities. The experimental results indicate that for granular soils the influence of penetration velocity on friction ratio is insignificant. In cohesive soils the increase in penetration velocity causes an increase in friction ratio which amounted to 80% at the maximum velocity used.
A Diffused Air Volume Indicator for Unsaturated Soils
Authors: Fredlund D. G.
Published: July 2008

The diffusion of air through saturated high air entry discs presents a serious problem in the testing of unsaturated soils. When determining either the strength (drained) or volume change characteristics of unsaturated soils, a technique must be available to measure the amount of diffused air in order for the appropriate corrections to be applied to the volume–weight relationships.The described diffused air volume indicator is a simple but effective means of measuring the quantity of diffused air. This technical note explains its construction and procedure of operation. Also outlined is the computational procedure for the correction factor that must be applied to the water volume change measurements. Numerous tests on the indicator show a reliability in the order of ±0.2 cc over a period of 2.5 weeks.
Construction pore pressures in clay foundations under embankments. Part I: the Saint-Alban test fills
Authors: Leroueil S. , Tavenas F. , Trak B. , Rochelle P. La , Roy M.
Published: July 2008

The detailed analysis of the pore pressures generated during construction under the center lines of four test embankments on a soft sensitive clay indicates a significant departure from the classical methods of pore pressure prediction.In the early stages of loading, the clay is overconsolidated and is characterized by a high Cv. As a result a significant consolidation occurs even in the very short duration of the construction. Due to this consolidation the vertical effective stresses increase rapidly until they reach the preconsolidation of the clay. At this point the clay becomes normally consolidated, and further loading occurs at constant effective vertical stress.The YLIGHT model of clay behaviour proposed by Tavenas and Leroueil may be used to fully understand this behaviour.In Part II, it will be shown that these findings apply in fact under most embankments and a prediction method will be proposed.
Construction pore pressures in clay foundations under embankments. Part II: generalized behaviour
Authors: Leroueil S. , Tavenas F. , Mieussens C. , Peignaud M.
Published: July 2008

The pore pressures observed under 30 embankments on clays of widely varying geological origin and geographical location are analysed to confirm the validity of the concepts developed from the Saint-Alban case history presented in Part I.It is shown that a significant consolidation does occur in all but one case in the early stages of embankment construction. As a result the vertical effective stress increases rapidly to a value equal to Pc. For further loading on the then normally consolidated clay the pore pressure coefficient [Formula: see text] assumes a value of 1.0.The observed behaviour is interpreted by means of the YLIGHT model of clay behaviour proposed by Tavenas and Leroueil and is shown to apply directly to all clays with an overconsolidation ratio less than 2.5, and with some modifications to heavily overconsolidated clays.The consequences of this behaviour on the analysis of stability and settlements of embankments are presented.