bluuebunny/crossref_metadata_2025 huggingface dataset:
A Kupffer-sejt gátlásának hatása az endotoxin indukálta gyulladásos válaszreakciókra és a máj mikrokeringési változásaira kísérletes obstructiós icterusbanr
Authors: Ábrahám Szabolcs , Szabó Andrea , Paszt Attila , Duda Ernő , Lázár György , ifj. Lázár György
Published: October 2009

Absztrakt

Bevezetés/Célkitűzés: A klinikai gyakorlatban az epeúti obstructio gyakran társul a mortalitás/morbiditás fokozódásával járó septicus szövődményekkel, melyek során a májban szisztémás gyulladásos válaszreakciók mellett jelentős mikrocirculatiós változások is létrejönnek. Ebben a folyamatban kiemelkedő kóroki szerepet töltenek be a máj Kupffer-sejtjei (KS). Kísérleteinkben a KS-ek és az epeútlekötés hatásait vizsgáltuk endotoxaemiában.  Anyag és módszerek: Kísérletünk első részében hím Wistar-patkányok túlélését vizsgáltuk 48 órás endotoxaemiában, epeútlekötés mellett vagy anélkül. Monitorizáltuk a pro-inflammatorikus TNF-α és IL-6 szérumszintek időbeni változását. Vizsgálataink második részében fluoreszcens intravitális mikroszkóp segítségével a máj mikrokeringési paramétereit vizsgáltuk, a kapilláris perfusiót, a leukocyta-endothelsejt interakciókat és a KS-aktivitás változásait. A KS-ek gátlását gadolínium-klorid- (GdCl3) előkezeléssel idéztük elő. Eredmények: A korai endotoxaemia jelentősen emelte az IL-6 és a TNF-α szérumszintjét. Ha az endotoxaemiát epeúti obstructióval kombináltuk, romlott a túlélés, emelkedett a TNF-α és az IL-6 szérumszintje, károsodott a máj perfusiója, fokozódott a KS-aktivitás és a leukocytakitapadások száma is. A KS-gátlás kedvezően befolyásolta a túlélést, mérsékelte a TNF-α és az IL-6 termelődést és a leukocyta-aktivitás fokozódását, a perfusio befolyásolása nélkül. Következtetések: Az epeútlekötés mellett az endotoxin által kiváltott gyulladásos és mikrokeringési válaszreakciók fokozódnak. A KS-gátlás gyulladásos reakciókat mérséklő hatása felveti a Kupffer-sejtek kiemelkedő kóroki szerepét a fenti mechanizmusokban.
Bal főhörgő-bifurcatio resectiója és anatómiai segmentectomia kettős granularis sejtes daganat miattr
Authors: Géczi Tibor , Furák József , Sztancsik Zsuzsanna , Vincze Árpád , Tiszlavicz László , Lázár György
Published: October 2009

Absztrakt

Esetismertetés:A szerzők egy 57 éves beteg esetét ismertetik, akinél panaszmentes állapotban, ernyőfényszűrésen derült fény bal oldali tüdőtumorára. Az elvégzett bronchoscopia, mellkas-CT és PET-CT a bal főhörgőben és a 6-os szegmentumhörgőben igazolt kettős, polypoid, granularis sejtes tumort a röntgen által jelzett 2-es szegmentumban elhelyezkedő, malignitasra gyanús terime mellett.Megbeszélés:A műtét során a 2-es szegmentumban lévő, az intraoperatív fagyasztásos szövettani vizsgálat alapján tuberculosisnak igazolódott elváltozást atípusos gépi ékresectióval, a granularis sejtes tumorokat 6-os segmentectomiával és a bal főhörgő bifurcatiójának resectiójával távolították el. Véleményük szerint a főhörgő-resectiós műtétek biztonsággal és jó eredménnyel végezhetők granularis sejtes tumorok esetén is, a sebészeti beavatkozás feltétlenül indokolt panaszokat okozó esetekben, illetve ha a nemritkán társuló kísérő elváltozás esetén malignitas gyanúja merül fel.
Regulation of major histocompatibility complex gene expression in thyroid epithelial cells by methimazole and phenylmethimazole
Authors: Giuliani Cesidio , Bucci Ines , Montani Valeria , Singer Dinah S , Monaco Fabrizio , Kohn Leonard D , Napolitano Giorgio
Published: October 2009

Increased expression of major histocompatibility complex (MHC) class-I genes and aberrant expression of MHC class-II genes in thyroid epithelial cells (TECs) are associated with autoimmune thyroid diseases. Previous studies have shown that methimazole (MMI) reduces MHC class-I expression and inhibits interferon-γ (IFN-γ or IFNG as listed in the MGI Database)-induced expression of the MHC class-II genes in TECs. The action of MMI on the MHC class-I genes is transcriptional, but its mechanism has not been investigated previously. In the present study, we show that in Fisher rat thyroid cell line 5 cells, the ability of MMI and its novel derivative phenylmethimazole (C10) to decrease MHC class-I promoter activity is similar to TSH/cAMP suppression of MHC class-I and TSH receptor genes, and involves a 39 bp silencer containing a cAMP response element (CRE)-like site. Furthermore, we show that C10 decreases MHC class-I gene expression to a greater extent than MMI and at 10- to 50-fold lower concentrations. C10 also reduces the IFN-γ-induced increase in the expression of MHC class-I and MHC class-II genes more effectively than MMI. Finally, we show that in comparison to MMI, C10 is a better inhibitor of specific protein–DNA complexes that are formed with a CRE-like element on the MHC class-II promoter. These data support the conclusion that the immunosuppressive mechanism by which MMI and C10 inhibit MHC gene expression mimics ‘normal’ hormonal suppression by TSH/cAMP.
Liver X receptor in cholesterol metabolism
Authors: Zhao Chunyan , Dahlman-Wright Karin
Published: October 2009

The liver X receptors (LXRs) are nuclear receptors that are activated by endogenous oxysterols, oxidized derivatives of cholesterol. There are two isoforms of LXR, LXRα (NR1H3) and LXRβ (NR1H2). Both LXRα and LXRβ regulate gene expression by binding to DNA sequences associated with target genes as heterodimers with isoforms of the retinoid X receptor (RXR), RXRα (NR2B1), RXRβ (NR2B2), and RXRγ (NR2B3). LXRs act as cholesterol sensors: when cellular oxysterols accumulate as a result of increasing concentrations of cholesterol, LXR induces the transcription of genes that protect cells from cholesterol overload. In this review, we summarize the roles of LXRs in controlling cholesterol homeostasis, including their roles in bile acid synthesis and metabolism/excretion, reverse cholesterol transport, cholesterol biosynthesis and uptake, and cholesterol absorption/excretion in the intestine. The overlapping and distinct roles of the LXRα and LXRβ isoforms, and the potential use of LXRs as attractive targets for treatment of cardiovascular disease are also discussed.
The stoichiometry in the paste hydration of C3S, alite and β-C2S cured at 5, 25 and 50°C
Authors: Sideris K. K.
Published: October 2009

The stoichiometry of the hydration process in the hardened paste of C3S, alite and β-C2S was investigated on the basis of surface area and crystal structure data calculations of the CSH-gel. The chemical compound of calcium silicate hydrate forming in the paste hydration of C3S, alite and β-C2S cured at 5, 25 and 50°C has a definite and stable composition during the whole hydration period, corresponding to the formula C4S3H2.
Engineering properties and structural implications of Portland limestone cement mortar exposed to magnesium sulphate attack
Authors: Hartshorn S. A. , Swamy R. N. , Sharp J. H.
Published: October 2009

The overall aim of this paper is to establish the engineering properties and material durability of Portland limestone cements, particularly when they are exposed continually to an environment rich in magnesium sulphate ions, and conducive to thaumasite formation. In particular, non-destructive and destructive tests were used to identify and examine the interaction of the changes in mechanical properties with the onset of sulphate attack. To achieve these objectives, 40 × 40 × 160 mm mortar specimens were subjected to air curing at 5°C and 20°C, and also immersed in 1·8% MgSO4 solution, again at 5°C and 20°C. The limestone content in the test specimens was kept at 0%, 5%, 15% and 35% replacement of cement by mass. The formation of thaumasite was checked and confirmed by x-ray diffraction supported by thermal analysis and scanning electron microscopy. The non-destructive tests used in the study included pulse velocity, dynamic modulus, shrinkage, expansion and changes in mass. In addition, flexural and compressive strengths were determined. All the tests were carried out up to one year. The results obtained from the tests have then been critically analysed. It is shown that mortar prisms containing 35% limestone and exposed to magnesium sulphate solution at 5°C suffered extensive damage and deterioration within one year. In addition, prisms containing 15% limestone gave strong signs of impending damage due to sulphate attack. The results of the non-destructive and destructive tests were highly complementary, and confirmed each other. The major mechanical deterioration occurred through the loss of compressive strength of almost 75% of that of the original unaffected mortar, whilst the loss in flexural strength was relatively small. The results strongly indicate that compression members, containing 35% limestone and exposed to aggressive sulphate environment at temperatures of about 5°C, can be seriously at risk in their ability to carry loads. On the other hand, it is unlikely that flexural members under these conditions would suffer the same degree of serious structural damage.
Characterisation of Portland cement clinker manufactured by down draft sintering and vertical shaft kiln processes
Authors: Nayak B.D , Mallick P.K
Published: October 2009

The chemical, mineralogical and cement properties of Portland cement clinkers manufactured from a raw mixture of lime saturation factor (LSF) 0·91 by the vertical shaft kiln (VSK) process and the down draft sintering (DDS) process, and a low lime clinker manufactured from a raw mixture of LSF 0·79 by the DDS process have been examined.
The role of magnesium during the hydration of C3S and C-S-H formation. Scanning electron microscopy and mid-infrared studies
Authors: Fernandez L. , Alonso C. , Hidalgo A. , Andrade C.
Published: October 2009

Mid-infrared (IR) spectra of a series of calcium silicate hydrates (C-S-H) gels synthesised from C3S in the presence of magnesium oxide show many similarities with the mid-IR spectra of pure C-S-H gels. However, the presence of the vibration bands attributed to brucite is observed in all spectra of C-S-H synthesised with MgO, although only the sample with the highest CaO/SiO2 ratio (1·8) reveals a large shoulder centred at 530 cm−1, which has been assigned to the presence of magnesium with a four-fold coordination inserted in the silica chains of the C-S-H gel. The postulated formation of magnesium silicate hydrates (M-S-H) gel was detected by scanning electron microscope and energy dispersive analysis of X-rays in some areas of the C-S-H gel with the lowest CaO/SiO2 ratio (0·66).
Supervising Engineers' forum 2009
Authors: Dun Richard
Published: October 2009

This year's Supervising Engineers' forum was once again held at the Manchester Conference Centre. As always the forum was well supported with over 200 attendees. The speakers' affiliations were spread throughout those concerned with dam and reservoir safety, including consulting engineers, the enforcement authorities, undertakers and product suppliers. All the presentations resulted in much discussion and debate. A number of the presentation will be included as full papers in future issues of Dams and Reservoirs.
Structural art: John S. Eastwood and the multiple arch dam
Authors: Jackson D. C.
Published: October 2009

In his landmark book The Tower and the Bridge, engineering professor/historian David Billington proposes the concept of ‘structural art’ and, with a focus on bridges, thin shell roofs and tall buildings, describes its relationship to the ideals of efficiency, economy and elegance. Dams are not discussed in The Tower and the Bridge, apparently because the massive gravity designs commonly built for major projects represent bulky, inefficient designs. Moving beyond gravity dam technology, this paper explores how John S. Eastwood's work designing multiple arch dams accords with Billington's idea of structural art. Eastwood built the world's first reinforced concrete multiple arch dam at Hume Lake, California in 1908 and during the last 15 years of his life became a prominent proponent of the technology. Eastwood's designs, how they correlate to the ideals of efficiency, economy and elegance, and how he integrated mathematical theory into his design methodology comprise the focus of this paper. In addition, issues of visual appearance and their effect upon professional acceptance of Eastwood's design are also considered. By employing the concept of structural art as a prism for studying multiple arch dams, the article elucidates an important aspect of hydraulic engineering history.
Canadian Society for Civil Engineering National History Committee
Authors: MacKenzie A. D.
Published: October 2009

This briefing looks at the objectives and current activities of the Canadian Society for Civil Engineering (CSCE).
Air channel testing of thermally bonded PVC geomembrane seams
Authors: Thomas R. W. , Stark T. D. , Choi H.
Published: October 2009

Polyvinyl chloride (PVC) possesses excellent thermal welding characteristics, such as a wide thermal seaming range and the absence of a need for surface preparation such as grinding. The focus of this study was to utilise these welding characteristics to develop a procedure for air channel testing of dual track thermal seams and recommend that destructive testing of PVC geomembranes be reduced and possibly discontinued. This is possible because of the development of a relationship between thermally welded seam burst strength and seam peel strength for a given sheet temperature. To develop this relationship, test welds were created using hot air and wedge welders at two different geomembrane temperatures, two different geomembrane thicknesses, three welding speeds, and three welding temperatures. The 72 seams created were evaluated by conducting ASTM D 6392 peel strength tests at room temperature (22.8°C) and a burst test developed herein at three different sheet temperatures. This paper presents the test results, which illustrate the importance of welding temperature and speed. The test results are also used to develop a relationship between seam peel strength and burst pressure, which can then be used to conduct field burst tests to ensure the specified seam peel strength(s) are satisfied along the entire seam length instead of over the limited seam length used in destructive tests.
Analysis of inextensible sheet reinforcement subject to downward displacement/force: non-linear subgrade response
Authors: Madhav M. R. , Umashankar B.
Published: October 2009

Geosynthetic materials used to reinforce earth fills, ground and slopes resist the destabilising forces by mobilising tensile forces in the reinforcement. In most studies, only the pullout resistance due to axial pull is considered in stability analysis. However, the kinematics of failure clearly establish that the reinforcement is displaced obliquely. In this paper, a novel approach is presented for the analysis of sheet reinforcement subjected to transverse force or displacement. Assuming a non-linear subgrade/fill response and an inextensible reinforcement, the resistance to transverse displacement is estimated. The response to the applied force is shown to depend not only on the interface shear characteristics of the reinforcement but also on the deformational response of the ground. The unique feature of this study is the coupling of normal displacements with pullout response. A relation is established between pullout resistance and transverse free end displacement. A parametric study quantifies the effect of soil and interface characteristics of reinforcement on the overall response.
Empirical equations for calculating the rate of liquid flow through composite liners due to geomembrane defects
Authors: Touze-Foltz N. , Giroud J. P.
Published: October 2009

This paper presents empirical equations for the evaluation of advective flow rates through composite liners (i.e. liners comprising a geomembrane and a low-permeability soil layer). The advective flow is due to defects in the geomembrane and depends on contact conditions between the geomembrane and the soil layer. Three types of defect (circular defects, defects of infinite length, and damaged wrinkles) and three types of contact conditions (excellent, good, and poor) are considered. The methodology for developing the empirical equations consists in selecting a mathematical expression for the empirical equations and selecting values for the unknowns of the empirical equations such that flow rates calculated using the empirical equations are as close as possible to flow rates rigorously calculated using existing analytical solutions. This was achieved by conducting numerical calculations for more than 120,000 cases defined by a wide range of values of the parameters (contact conditions, defect type and size, soil layer thickness and hydraulic conductivity, and hydraulic head). As the empirical equations are much simpler than the analytical solutions, they provide design engineers with a practical tool for evaluating flow rates through composite liners.
Hydraulic behaviour of soil–geocomposite layers in slopes
Authors: Iryo T. , Rowe R. K.
Published: October 2009

The behaviour of initially unsaturated soil–geocomposite layers in slopes subject to infiltration is investigated using numerical experiments. The post-infiltration performance is also studied. A series of transient finite element analyses of soil–geocomposite layers is conducted for a variety of soils, slopes and infiltration rates. The influence of these variables on the effectiveness of geocomposites as a drainage material and as a capillary barrier is discussed. The effect of entrapped air within a geotextile is also examined. This study shows that the geocomposite drains more water with a decrease in slope angle and an increase in infiltration rate (i.e. the geocomposite works as a capillary barrier for smaller infiltration rates and steeper slope of the soil–geocomposite layers). It is also shown that the soil immediately above the geocomposite becomes wet before the geocomposite starts draining water, and it remains wet for a relatively long period of time after the infiltration event.
Effect of Rate of Loading on the Strength of Clays and Shales at Constant Water Content
Authors: Casacrande A. , Wilson S. D.
Published: October 2009

Synopsis

Investigations performed at Harvard University during the past three years show that some types of brittle undisturbed clays and clay shales creep under a sustained load, and that they ultimately fail under a sustained load appreciably less than the strength indicated by a normal laboratory compression test. The shear strengths of six such soils were found to be reduced to 40–80 per cent. of their normal values in thirty days. This may explain some slides which have developed on slopes that stood for many years without noticeable movement.

In contrast, it was found that two laboratory compacted soils, and one undisturbed soil which was not fully saturated, tended to become stronger and stiffer under sustained loads, even though water content was kept constant. These results may prove of value in connexion with the design of embankments.

Des recherches effectuées à 1'Université de Harvard, au cours de ces trois dernières années, montrent que quelques types d'argiles et de schistes argileux friables non remués cheminent sous une charge sontenue et qu'ils finissent par s'effondrer sous une charge soutenue bien inférieure à la résistance indiquée par un essai normal de compression en laboratoire. On a trouvé pour six de ces sols que leur résistance au cisaillement se trouvait réduite de 40 à 80 pour cent de sa valeur normale en 30 jours. Ceci peut expliquer quelques glissements qui se sont produits sur des pentes qui étaient demeurées pendant de nombreuses années sans mouvement appréciab1e.

Par contre, il a été trouvé que deux sols compressés en laboratoire, et un sol non remué quin'était pas complètement satré, avaient tendance à devenir plus résistants et plus fermes sous des chargas soutenues, quoique la teneur en eau ait été maintenue constante. Ces résultats peuvent avoir une certaine valeur pour l'étude des remblais.
A Constant-Pressure Control for the Triaxial-Compression Test
Authors: Bishop Alan W. , Henkel D. J.
Published: October 2009

Synopsis

The use of the triaxial-comprssion test, both for routine testing and for reserach, requies a constant cell pressuer for periods ranging from a few minutes to many weeks. The self-compen-sating mercury coutrol has been developed to maintain an accurately constant pressure during tests of long duration, and has proved simple, efficient, and reliable in practice.

L'essai de compression triaxial dont on se sert pour les essais routiniers et pour les recherches nécessite une pression constante dans la chambre de compression, pour un temps variant de quelques minutes à plusieurs semaines.

Le contrô;e automatique par mercure a été développé pour maintenir une pression constante exacte pendant les essais de longue durée, et s'est prouvé d'utilisation simple, efficace, et sûre.
The Single Pile Subject to Horizontal Force
Authors: Rowe P. W.
Published: October 2009

Synopsis

The value of the modified “coefficient of horizontal subgrade reaction” for a single pile in cohesionless soil, called the soil stiffness modulus, is found to depend on the flexure and geometry of the pile. The form of the relation between the modulus for a pile of width B and that for a continuous wall is estimated from the φm-mobilization theory, and is found to correspond with available test data. A procedure for estimating the load/deflexion curve for a pile is proposed which takes account of the properties of the soil and the pile and the relation between these properties.

La valeur du “coefficient corrigé de réaction horizontale souterraine” d'un pilier unique en sol sans cohésion, appelée module de rigidité du sol, apparaît dépendante de la flexure et du dessin du pilier. La forme de relation entre le module pour un pilier de largeur B et pour un mur continu est estimée selon la théorie de mobilisation par φm et apparaît correspondante avec les données d'essais disponibles.

On propose une méthode d'estimation de la courbe de charge-déflexion pour un pilier, qui tient compte des propriétés du sol et du pilier et de la relation entre ces propriétés
Contribution to the Analysis of Seepage Effects in Backfills
Authors: Gray Hamilton
Published: October 2009

Synopsis

An analytic solution for a type of seepage com-monly occurring in the backfill of retaining walls leads to a mathematical expression for water pressure on the lower boundary of the potential “sliding wedge” of earth. This pressure is the function of the angle a between the wedge boundary and the vertical, and may be written: whereγw is the unit weight of water and H the depth of the backfill. An accompanying graph of F (α) eliminates the necessity for plotting a flow net and for sealing the water pressure on the lower boundary of the wedge.

Une solution analytique pour une sorte de suinte-ment se produisant fréquemment dans le remblai des murs de soutbnement amène à une expression mathématique pour la pression d'eau à la limite inférieure de la masse triangulaire potentielle de glissement de terre. Cette pression est fonction de l'angle α entre la et peut s'écrire dans laquelle γw est l'unité de poids de l'eau et H la profondeur du rem- blai. Un graphique ci-joint de F (α) supprime le besoin de relever le réseau de lignes de courant et tracer à I'échelle la pression d'eau sur la limite inférieure de la masse.
The Stability of Embankments of Frictional Material Retaining a Low-Frictional Fill
Authors: Naylor A. H. , Stuart J. G.
Published: October 2009

Synopsis

This Paper gives the results of calculations of the stability of an embankment supporting a low-frictional fill. The work arose from an analysis of the stability of an embankment supporting a slurry consisting of a fine limestone silt with a proportion of clayey material which is pumped to settle in ponds. The embankment is made of coarse crushed stone waste, but it is desirable for economic design to reduce the amount of embankment material to a minimum consistent with safety.

If the bank is raised so as to be always level with the slurry, the angle of the interface between the bank and slurry can be arbitrarily selected and the problem is to find the optimum interface angle. The slurry consolidates, and the vane shear strength at any time is found to increase approximately linearly with depth at any point. This led to the consideration of the general case of a frictional embankment supporting a frictional fill.

Since the bank material is purely frictional and the slurry has a strength increasing linearly with depth, similar slip surfaces are equally likely at any depth, and the problem becomes one of zonal failure with a complex slip field, a discontinuity at the interface, and a combination of convex and plane surfaces within the bank. The results obtained by graphical analysis are compared with the slip field obtained experimentally using small-scale two-dimensional models.

Cet article présente les résultats des calculs de la stabilité d'un terrassement composé de deux sols sans cohésion. Les auteurs ont été conduits à considérer ce problème par une étude de la stabilité d'un terrassement qui contient une boue (un remblai hydraulique) composée d'un mélange de limon fin calcaire et d'argile. Le terrassement est construit d'un mélange de pierres cassées à grains grossiers.

Ce terrassement est construit de façon à restes toujours au même niveau que la boue. L'angle dièdre entre le terrassement et la boue peut être déterminé à volonté et il s'agit de réduire la quantité de matériaux nécessaire à la stabilité du terrassement —et par consequent, de réduire cet angle dièdre— sans réduire en même temps la sécurité du barrage.

La résistance du cisaillement de la boue dépend directement de la profondeur de suite qu'on peut considérer cette boue comme un sol avec frottement.

Des surfaces de glissement sont également probables à toute profondeur. Nous nous trouvons done devant un problème de rupture zonale à forme complexe des surfaces planes, convexes et concaves. Les résultats de l'analyse graphiques sont donnés et les surfaces de glissement théoriques ont été comparés aux essais sur modèles reduits en deux dimensions.
Interference Between Foundations, with Special Reference to Surface Footings in Sand
Authors: Stuart J. G.
Published: October 2009

Synopsis

The changes in bearing capacity, which occur when foundations form groups, has been the subject of a number of experimental investigations which have been carried out with model foundations of various sizes and depths, both in sand and clay.

This article is mostly concerned with the case of two foundations at or near the surface of a sand, and a theoretical solution to this problem is described.

Laboratory tests on small-scale model foundations have been carried out, and the results compared with the theory. In general good agreement is obtained, but the work suggests the need for further investigation into the effect of foundation shape on the bearing capacity.

La question des variations de la capacité portante de groupes de fondations a été le sujet d'un certain nombre d'investigations expérimentales (utilisant des modéles) avec fondations de diverses dimensions dans le sable et dans l'argile.

Cet article s'interesse surtout au cas particulier de deux fondations, á la surface ou á proximité de la surface, d'un sable, et on traite ici d'une solution théorique de ce probléme.

Les calculs théoriques sont donnés et comparés avec les essais sur modéles réduits. En général les résultats s'accordent, mais le travail réalise demanderait des recherches supplémentaires sur l'effet de la forme des fondations sur la capacité portante.
Consolidation of Compacted and Unsaturated Clays
Authors: Barden Laing
Published: October 2009

Synopsis

A review is made of published evidence on the physical properties of unsaturated and compacted clays with the object of recognising the more important factors affecting the consolidation process in such soils. An attempt is then made to formulate and solve a set of general equations to describe the consolidation process. Because of the complexity of these equations it is found desirable to sub-divide the process into a number of less general treatments, each being relevant to a particular range of saturation values. The treatments include the effects of decreasing permeability and a compressible pore fluid, and the resulting non-linear partial differential equations are solved by finite difference approximations on a digital computer. The computed results exhibit the two important characteristics found in consolidation tests on unsaturated clay, viz. a continuously curved settlement/root-time plot and a mid-plane pore pressure dissipation plot which is flatter than the theoretical Terzaghi plot. As a result of this preliminary investigation it is tentatively concluded that a major cause of this difference between Terzaghi theory and the observed behaviour of compacted clay, in the region of or wetter than optimum, is the marked decrease in permeability that occurs during the consolidation process, the effect of the compressibility of the pore fluid being of secondary importance.

On passe en revue les renseignements publiés sur les propriétés physiques des argiles non saturées et compactées afin de reconnaître les facteurs importants affectant le procédé de consolidation dans de tels sols. Puis on essaye d'exprimer et de résoudre un groupe d'équations générales pour décrire le procédé de consolidation. A cause de la complexité de ces équations il est utile de subdiviser le procédé en un certain nombre de traitements moins généraux, chacun concernant une série particulière de valeurs de saturation. Les traitements comprennent le décroissement de la perméabilité ainsi qu'un fluide interstitiel compressible, et les équations différentielles partielles non-linéaires en résultant sont résolues sur une calculatrice digitale par des approximations de différence déterminées. Les résultats computés font ressortir les deux caractéristiques importantes découvertes dans les essais de consolidation sur de l'argile non saturée, à savoir un tracé graphique en courbe continue du tassement et de la racine de la durée, et un tracé graphique de la dissipation de la pression interstitielle en plan moyen qui est plus plat que le tracé théorique de Terzaghi. A la suite de cette enquête préliminaire on conclut à titre d'essai qu'une cause principale de cette différence entre la théorie Terzaghi et le comportement observé de l'argile compactée, dans le voisinage de l'optimum ou plus humide, est le décroissement marqué en perméabilité qui se produit pendant le procédé de consolidation, l'effet de la compressibilité du fluide interstitiel étant d'une importance secondaire.
Stress-Strain Relations For Clays: An Energy Theory
Authors: Palmer Andrew C.
Published: October 2009

Synopsis

A theory for the internal energy of clay/water systems is derived. In this theory the observed critical state property is central. Only when the relation between mean compressive stress and void ratio is the same as that in the critical state is there a balance between interparticle forces and external forces. This concept leads to a description of internal energy changes in triaxial tests; if this is combined with a description of plastic dissipation, an energy balance can be written. Comparison with experiments on kaolin shows a simple pattern in the behaviour of the parameter describing dissipation. A stress-strain relation for any triaxial stress path can now be derived. A final section of the Paper explores the consequences of linking this with the normality concept of plasticity theory.

Une théorie est dérivée pour l'érgie interne des systémes argile/eau. Dans cette théorie la qualité de l'état critique observeé; est centrale. Seulement dans les cas où le rapport entre la contrainte de compression moyenne et l'indice de vide est le même que celui de l'état critique se trouve un e´quilibre entre les forces entre les particules et les forces extérieures. Ce concept méne à une description des changements d'énergie interne dans les essais triaxiaux; si ceci comporte aussi une description de dissipation plastique un equilibre d'é;nergie peut être posé. La comparaison avec des expériences sur le kaolin fait ressortir une forme simple dans le comportement du paramétre décrivant la dissipation. Un rapport contrainte-déformation pour toute trajectoire de contrainte triaxiale peut maintenant être déduit. Une section finale de l'exposeé examine les conséquences d'établir un lien entre ceci et le concept de l'état normal de la théorie de plasticité.
Deepsounding Test Results and the Settlement of Spread Footing on Normally Consolidated Sands
Authors: Thomas D.
Published: October 2009

Synopsis

For settlement estimations of spread footings based on deepsounding test results on sands it has been usual to utilize the analysis proposed by Buisman which employs a constant of compressibility derived from C ≤ 3Cka/2po, and the compression equation Buisman also showed that E ≤ 3Cka/2.

The first part of the Paper describes an experimental investigation which was carried out to compare the penetration resistance and the compressibility characteristics of three sands. The results determined a relationship between cone resistance and E/(1–ν2) which was independent of the sand grading, particle size and overburden pressure for normally consolidated sands.

In the second part of the Paper the experimental results are discussed with respect to field testing, in situ ground conditions and the settlement of footings. Estimated and observed settlements are compared for several sites for which cone resistance/depth profiles are available.

A good agreement between estimated and observed settlement was obtained provided that a correction was made to the estimated settlement values to allow for the proportion of the ultimate bearing capacity of the soil mobilized at the bearing pressure imposed by the foundation.

Dans le cas d'évaluations d'empattements superficiels sur le sable il a été habituel d'utiliser l'analyse proposée par Buisman qui utilise une constante de compressibilité tirée de C ≤ 3Cka/2po, et de l'équation de compression Buisman démontra aussi que E ≤ 3Cka/2.

La première partie de l'exposé décrit une enquête expérimentale qui fut exécutée pour comparer la résistance à la pénétration et les caractéristiques de compressibilité de trois sables. Les résultats établirent un rapport entre la résistance au cône et E/(1–ν2) qui était indépendant de la catégorie de sable, de la taille des particules et de la pression de surcharge pour des sables normalement consolidés.

Dans la seconde partie de l'exposé les résultats expérimentaux font l'objet de discussions relativement aux essais sur place, aux conditions du sol sur place et au tassement des empattements. Des tassements évalués et observés sont comparés dans les cas de plusieurs emplacements pour lesquels existent la résistance au cône/des profils en profondeur.

Une bonne correspondance entre le tassement évalué et observé fut obtenue à condition qu'une correction soit apportée aux valeurs de tassement évaluées pour tenir compte de la proportion de la capacité de charge ultime du sol mobilisé sous la pression de charge imposée par la fondation.
The Behaviour Of Axially Loaded End-Bearing Piles
Authors: Poulos H. G. , Mattes N. S.
Published: October 2009

Synopsis

The behaviour of a single axially loaded end bearing pile in an ideal elastic soil is analysed and solutions are given for the load distribution within the pile, and the top and tip movements of the pile for a wide range of cases. It is shown that the behaviour of the pile is largely influenced by the length to diameter ratio, the stiffness of the pile relative to the surrounding soil and the relative stiffness of the bearing stratum. It is found that very slender piles act effectively as floating or ‘friction’ piles. The influence of local yield between the pile and soil is also examined and the resultant increase in top displacement is found to be largely dependent on the distribution of adhesion along the pile.

Comparisons between the observed behaviour of end-bearing piles, obtained from published measurements in field tests, and the theoretical behaviour show good agreement.

Le comportement d'un pilotis à charge axiale unique et supportant les charges à l'extrémité dans un sol élastique idéal est analysé et l'on donne des solutions relativement à la répartition des charges dans le pilotis et lcs déplacements aux sommets et aux extrémités du pilotis se rapportant à une gamme de cas étendue. On fait apparaître que le comportement d'un pilotis est influencé en grande partie par le rapport de la longueur au diamètre, de la rigidité du pilotis par rapport au sol environnant et de la rigidité relative de la couche supportant les charges. On s'est aperçu que des pilotis légers peuvent opérer efficacement en qualité de pilotis de ‘frottement’ ou flottants. L'influence de la limite élastique locale entre le pilotis et le sol est aussi examinée et l'on trouve que l'accroissement de mouvement au sommet en résultant dépend largement de la répartition de l'adhésion le long du pilotis.

Une bonne correspondence a été obtenue en ce qui concerne les comparaisons relatives au comportement observé des pilotis supportant des charges à leurs extrémités, provenant des mesures publiés à la suite d'essais sur place, et du comportement théorique.
Consolidation of Deep Deposits of Homogeneous Clay
Authors: Raymond G. P.
Published: October 2009

Synopsis

Synopsis

Under embankments and earth dams the load ratio will generally be greater than two (the standard oedometer ratio) to a depth of twice the embank- ment height. In deep deposits large variations in compressibility and permeability will occur through- out the depth of the deposit. In order to help account for these variations a theory and solutions are presented to cover a large number of practical problems involving one-dimensional drainage for a homogeneous soil which obeys the relationship

The theory presented often predicts large differences from rates of consolidation which might have been predicted from the assumptions of the standard linear theory. An approximate method of applying the theory to the consolidation of soils by drain wells is presented. Two case records are referred to which show variation from the linear theory predictions which could be accounted for by the theory pre- sented.

Sous des remblais et des barrages en terre le taux de chargement est en g énéral supérieur à deux (le taux mdométrique standard) à une profondeur du double de la hauteur du remblais. Dans les dépôts profonds de grandes variations de compressibilité et de perméabilité se produisent dans toute la profon- deur du dépot. Afin d'aider à expliquer ces varia- tions, une théorie et des solutions sont présentées pour couvrir un grand nombre de problèmes pratiques entraînant un drainage à une dimension pour un sol homogène qui suit le rapport

La théorie présentée prévoit souvent de grandes différences avec les taux de consolidation qui auraient pu être prévus a partir des suppositions de la théorie linéaire standard. On présente une méthode approximative d'appliquer la théorie à la consolidation des sols au moyen de puisards. Deux cas enregistrés sont rappelés qui font apparaître une variation par rapport aux prévisions de la théorie linéaire qui pourrait être expliquée par la théorie présentée.
Stresses and Displacements in an Elastic Layer due to Inclined and Eccentric Load Over a Rigid Strip
Authors: Milovic D. M. , Touzot G. , Tournier J. P.
Published: October 2009

Synopsis

Using the finite element method, a set of influence factors for the stresses in, and the surface displacements of, an elastic layer of finite thickness have been obtained.

Stresses and displacements due to inclined and eccentric load over a rigid strip have been calculated for the ratio H/B=1·0, 2·0 and 3·0, where H is the thickness of the compressible layer and B is the width of the rigid strip foundation, and for Poisson's ratio μ=0·005, 0·30 and 0·45.

The values of the stress and displacement coefficients are given in tabular form and some of them are also presented graphically

En utilisant la méthode des éléments finis, des facteurs d'influence pour le calcul des contraintes à l'intérieur du milieu et des déplacements à la surface sont obtenus dans le cas d'une couche élastique d'épaisseur finie.

Les contraintes et les déplacements produits par une force inclinée et excentrée a gissant sur une bande rigide ont été calculés pour le rapport H/B=1·0, 2·0 et 3·0, H étant l'épaisseur de la couche compressible, et B la largeur de la bande rigide, et pour le coefficient de Poisson μ=0·005, 0·30 et 0·45.

Les valeurs des facteurs d'influence des contraintes et des déplacements sont données sous forme de tableaux et certaines sont présentées graphiquement.
The Correlation of Cone Size in The Dynamic Cone Pennetration Test with the Standard Pennetration Test
Authors: Mohan D. , Aggarwal V. S. , Tolia D. S.
Published: October 2009

Synopsis

Dynamic cone penetration tests have been con ducted in the field with varying cone sizes at different sites, with a view to finding a suitable size of cone for future adoption in the field investigations. The study has shown the possibility of relating the ratio of dynamic cone and the standard penetration rapport test values made with the standard 51 mm o.d. split spoon sampler. On the basis of the exhaustive dynamic penetration tests, a cone of 62.5 mm is recommended.

On a procédé à des essais dynamiques de pénétration au cône sur place au moyen de cônes de tailles variables dans différentes localités, dans le but de trouver une taille de cône qui convienne pour qu'elle soit adoptée à l'avenir dans les recherches sur place. L'étude a fait apparaitre la possibilité d'établir un entre le taux du cône dynamique et les valeurs des essais de pénétration standard et l'appareil de prise d'ećhantillon à cuillère à fente à diamètre extérieur de 51 mm. En partant de l'étude approfondie qui a été effectuée pour standardiser la taille du cône pour les essais de pénétration dynamique, fondie qui a été effectuée pour standardiser la taille du c^one pour les essais de pénétration dynamique, on recommande un cône de 62,5 mm.
Earth Pressure Against the Abutments of a Rigid Frame Bridge
Authors: Broms B. B. , Ingelson I.
Published: October 2009

Synopsis

The lateral earth pressure which acts on one of the abutments of a 500 ft long rigid frame bridge has been measured during the compaction of the granular backfill behind the two abutments. The lateral earth pressures have also been measured after completion of the bridge. The measurements indicate that high lateral earth pressure developed during the compaction of the backfill. Lateral earth pressures were also high during the following summer, after the bridge had been completed, when the bridge slab expanded and pushed the abutment walls against the backfill.

La poussée latérale des terres agissant sur l'une des culées d'un pont à cadre de 150 m de long a été mesurée pendant le compactage du remblai granulaire derriere les deux butées. Les poussées latérales des terres ont également été mesurées après l'achèvement du pont. Les mesures indiquent qu'il se produisit une grande poussée latérale des terres durant le compactage du remblai. Les poussées latérales des terres furent également élevées au tours de l'été qui suivit l'achèvement du pont, lorsque le tablier se dilata et poussèrent les parois des culées centre le remblai.
The geometric design of long cofferdams
Authors: King G. J. W. , Cockroft J. E. M.
Published: October 2009

The analytical solution to the problem of seepage into a partially excavated cofferdam in finite depth of permeable material, derived by the method of conformal mapping, is presented. Analytical and graphical solutions for no excavation and for full excavation within the cofferdam are given and a graphical solution for a cofferdam in infinite depth of permeable material, which differs in detail to that given by Harr and Dean (1961) is given.

The range of geometries for which it is reasonable to apply the infinite depth solution is indicated by a comparison of finite and infinite depth solutions for cofferdams with no excavation. For other geome- tries, alternative solutions based on the solutions for no excavation and for full excavation are considered. Numerical comparisons, with results obtained by the method of electrical analogy, show that a modification of the solution for no excavation provides the best solution for most practical geo- metries.

Finally, simple design procedures, based on this modified solution, are illustrated by numerical examples.

On présente la solution analytique du problème de la percolation dans un batardeau partiellement excavé dans une épaisseur finie de matériau perméable, basée sur la méthode des transformations conformes. On donne les solutions analytiques et graphiques pour I'absence d'excavation et l'excavation complete du batardeau. On donne aussi une solution graph- ique pour le cas d'un batardeau dans une épaisseur infinie d'un materiau perméable, qui differe dans ses détails de celle donnée par Harr et Dean.

Grâce à une comparaison entre les solutions obtenues pour une epaisseur finie ou infinie on indique pour les batardeaux sans excavation, le domaine des géométries pour lesquelles on peut raisonnablement appliquerla methode correspondant à une épaisseur infinie. Pour les autres géométries, on examine les autres solutions que I'on pourrait utiliser, basées sur les méthodes sans excavation ou avec excavationcompléte. Des comparaisons numériques, utilisées conjointement avec les resultats obtenus par la methode d'analogie électrique, montrent qu'une adaptation de la solu- tion sans excavation donne la meilleure solution pour la plupart des géométries utilisées en pratique.

Enhn à l'aide d'exemples numeriques, on numéruqyes, onillustre des processus tres simples de calcul bases sur cette solution adaptéee.