bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of sucrose on retardation of Portland cement
Authors: Luke K. , Luke G.
Published: October 2009

Early-stage reactions of Portland cement are markedly influenced by the presence of sucrose. Compositional variations in the aqueous phase are presented with some accompanying microstructural and physical data for sucrose concentrations ranging from 0·1% to 2·0% by weight of cement. Approximately 50–80% of the sucrose was consumed in the initial 30 min of hydration and is assumed to be incorporated into a gel-like reaction product. Aqueous-phase analysis suggests the gel-like material to be a calcium aluminosulphate probably incorporating silicate ions. Increased addition of sucrose significantly modified the reaction, as did delayed addition.
A new model to calculate water permeability of cement-based materials from MIP results
Authors: Aït-Mokhtar A. , Amiri O. , Dumargue P. , Sammartino S.
Published: October 2009

In this article, we have established an analytical model of cement-based material permeability. The permeability is expressed in function of porosity, tortuosity, constrictivity factor and critical pore radius of the material. The modelling is based on the use of a tridimensional cubic pore network. Two types of measurements are carried out on mortars and cement paste: (a) mercury intrusion porosimetry (MIP) measurements so as to determine the model entry parameters which allow calculation of the ‘theoretical’ permeability; (b) direct water permeability measurements by the application of the Darcy's law so as to validate the model. The calculated and measured permeabilities are globally in the same order of magnitude. However, some differences are noted. They can be explained by the complexity of correctly estimating some model entry parameters (e.g. tortuosity). Moreover, the permeability expression established shows that it is more affected by tortuosity and critical pore radius variations than by porosity or constrictivity.
Reconsideration of ASTM C1260 test results in the light of a recent kinetic model
Authors: Mangialardi T.
Published: October 2009

A recent kinetic model based on nucleation and growth kinetics was used to elucidate the influence of the type (fineness, total alkali content) of Portland cement on the diagnosis of the ASTM C1260 test method with regard to the alkali–silica reactivity (ASR) of five natural siliceous sands of known petrographic characteristics and field performance. Some attempts were also made to apply the kinetic model for interpreting the ASTM C1260 test results obtained when an appositely modified version of this test method was used to assess the capability of lithium nitrate additions in suppressing or mitigating deleterious ASR with a given aggregate. It was found that the kinetic model is capable of discriminating the alkali-reactivity of the sands investigated, through the use of a plot of the two kinetic parameters, M and ln k, derived from the model and assuming ln k as a reactivity criterion. Differently from what was observed using a percentage expansion criterion for defining potentially reactive aggregates, the use of ln k as a reactivity criterion yields an ASR diagnosis for every sand that is independent of the type of Portland cement used in the ASTM C1260 test. A modified version of the ASTM C1260 test procedure can be successfully used to assess the capability of lithium nitrate additions in suppressing deleterious ASR. Application of the kinetic model provides a suitable means of determining effective lithium dosages for deleterious ASR suppression in ASTM C1260 tests.
Reactions of sulphate-resistant Portland cement and its blends with silica fume and aqueous magnesium sulphate
Authors: Brew D. R. M. , Glasser F. P.
Published: October 2009

Mixtures of sulphate-resistant Portland cement, Ca(OH)2 and silica fume were moist cured at 55°C for approximately twelve months and subsequently reacted with 0·5 M MgSO4 solution at 85°C for six months. Marker experiments in conjunction with electron microprobe analyses were used to elucidate reaction mechanisms. Two distinct patterns of mineral zonation were observed in altered cement paste: sharply banded and irregularly banded. Reasons for the differences in microstructure are explained in terms of differing reaction mechanisms, which are primarily related to matrix permeability. The mineralogy of the degraded cement was determined; besides gypsum and an M-S-H phase, two phases hitherto unreported in Portland cement occurred: magnesium hydroxysulphate, Mg6(OH)10SO4·3H2O, and, in one blend composition, a clinohumite-like phase. Observations are made on the probable durability of conventional concretes in contact with MgSO4(aq).
Production of multiphase plaster and anhydrite from Mae Moh flue-gas desulphurised gypsum
Authors: Jinawath S. , Thitianan C.
Published: October 2009

Precleaning of flue-gas desulphurised gypsum (FGD gypsum), a waste product from the Mae Moh power plant, by a hydrocyclone classifier, acid leaching and sedimentation significantly reduced the content of impurities in the FGD gypsum, such as fly ash, quartz and iron compounds, resulting in a lighter colour and higher purity product (95·60% dihydrate). Subsequently, the semidry acid-anhydrite technique was adapted to the calcining of the precleaned FGD gypsum to reduce the transition temperature of the anhydrite. Accordingly, low-temperature multiphase plaster was prepared using a two-step calcination. The FGD gypsum with sulphuric acid was first calcined at 60°C for 1 h and then recalcined at 150°C for 3 h. The obtained multiphase plaster consisted of 29% hemihydrate, 60% anhydrite II, 10% anhydrite III and 1% dihydrate. At a water to plaster ratio of 0·6, its viscosity and initial and final setting times were 3633 centipoises and 16·28 and 27·83 minutes, respectively. The flexural strength and hardness of the plaster specimens were 5·07 and 10·79 N/mm2. However, the remaining impurities imparted a buff colour to the multiphase plaster. Anhydrite (95% anhydrite II) with crystal morphologies ranging from prismatic to plate-like shapes was achieved by calcining at 100°C for 3 h. Its whiteness measured according to the CIE system was 92·64%.
Durability of plain and blended cements in marine environments
Authors: Al-Amoudi O. S. B.
Published: October 2009

This study was conducted to investigate the durability of two plain cements (Type I and Type V) and three blended cements prepared with fly ash (FA), silica fume (SF) and blast furnace slag (BFS), in marine environments. Cement paste, mortar and reinforced concrete specimens were exposed to sea water for a period of 2 years. In addition to inspecting the specimens visually, the performance of both plain and blended cements was evaluated by measuring the strength development, reduction in compressive strength, expansion, weight change, reinforcement corrosion and conducting chemical and mineralogical analyses. The visual inspection and compressive strength results indicated that the sulphate attack was somewhat hindered in plain and blended cements despite the high sulphate concentration in the marine environments. The data on reinforcement corrosion confirmed the superior performance of silica fume cement in sea water, followed by blast furnace slag and fly ash cements. The corrosion resistance of Type I cement was marginally better than that of Type V cement. Even though the Cl−concentration and Cl−/OH−ratio in the SF and BFS cements were the highest and much more than the threshold values, the intensity of reinforcement corrosion in these cements was less than that in the plain cements.
Influence of Al2O3 content on hydraulic reactivity of granulated blast-furnace slag, and the interaction between Al2O3 and CaO
Authors: Wang P. Z. , Trettin R. , Rudert V. , Spaniol T.
Published: October 2009

This paper presents results of investigations on the influence of the Al2O3 content of granulated blast-furnace slag (GBFS) on its hydraulic reactivity. Al2O3 content up to 15% has a positive effect on the reactivity of GBFS. Due to the interaction between the Al2O3 and CaO contents the effectiveness of the Al2O3 depends also on the CaO content, which is clearly more significant in lime-rich slags than in slags that are poor in lime. For the optimisation of the quality of GBFS it is recommended to maintain Al2O3 over 10·5% and CaO over 40%. It was found by27 Al NMR investigation that aluminium in GBFS is mainly tetrahedrally coordinated. However with rising Al2O3 so-called ‘tricluster’ is formed in the slag glasses. This leads to a reactivity reduction.
1870s innovation in London Canada's Blackfriars Bridge
Authors: Bartlett F. M. , Graham J. M. , Camiletti J.
Published: October 2009

Blackfriars Bridge in London, Canada, is a wrought-iron bowstring-arch-truss bridge fabricated by the Wrought Iron Bridge Company of Canton, Ohio and erected in 1875. Although typical of the 19 km of wrought-iron bowstrings constructed by the company in this period, the bridge is one of the first to feature a ‘double-panel’ web diagonal arrangement that was patented in the USA one year after the bridge was constructed. Considering the state of structural engineering knowledge in the 1870s, this paper investigates whether the structural response of the double-panel diagonal could have been correctly analysed by the original designers or whether the bridge may have been constructed as a prototype to validate this innovative feature. Design live loads are determined from values specified in the company's 1874 book of designs that depend on whether the bridge is located in the country, a town, a second-class city or a first-class city. The truss, statically indeterminate to the thirteenth degree, can be manually analysed neglecting slender web diagonals in compression if the participation of vertical members above the double-diagonals is ignored. The patent highlights the structural contribution of these members, however, and because their participation can only be accurately assessed using modern computer analyses, Blackfriars Bridge may have been built as a prototype to validate the double-panel design feature.
Clogging and flow characteristics of a geosynthetic drain confined in soils undergoing consolidation
Authors: Ghosh C. , Yasuhara K.
Published: October 2009

This paper describes clogging and in-plane flow characteristics of a permeable geosynthetic layer confined within fine-grained soils that undergo time-dependent settlement. The drain layer was placed within a slurry, and measurement of water from the drain layer was recorded. In-plane flow capacity of the drain layer was checked at the end of consolidation. The permeability of the geosynthetic drain layer was found to be at least 105 times the corresponding permeability of the soil. In order to prevent clogging, a hybrid drain system consisting of a thin sand mat between the soil and geosynthetic layer was investigated. This system showed excellent drainage performance due to good filtering capability of the thin sand mat. New terms, such as ‘permeability factor’, ‘drain performance factor’, ‘confining pressure factor’ and ‘clogging potential’ of drain, are defined and evaluated from the experimental data. Clogging potential of the hybrid drain layer was found to be low (< 2), and was observed to reduce with an increase in consolidation pressure. Without the thin sand mat the clogging potential showed an increasing trend with increasing consolidation pressure. Finally, this paper recommends potential application of the hybrid drain system to improve stability of soil structures constructed with poorly draining backfills such as Kanto loam in Japan.
Development of rational seismic design method for geogrid-reinforced soil wall combined with fibre-mixed soil-cement and its applications
Authors: Izawa J. , Ito H. , Saito T. , Ueno M. , Kuwano J.
Published: October 2009

ABSTRACT: The combined use of a geogrid-reinforced soil wall with a fibre-mixed soil-cement wall (GRSW-FSC) has recently been developed, and its application has grown rapidly. The results of previous centrifuge shaking-table tests have clearly shown the effectiveness of the GRSW-FSC to achieve a higher seismic stability than conventional reinforced soil walls. The current research investigates the effect of geogrid arrangement and the width of the soil-cement wall in order to develop a new rational design method for GRSW-FSCs in field applications. To achieve this goal, a series of centrifuge shaking-table tests was conducted. The results show that even if the width of the fibre-mixed soil-cement wall is reduced by 20%, the GRSW-FSC has enough seismic stability to resist severe seismic motions. Moreover, the effect of the length of the geogrid located at the upper part of the wall plays a more important role in seismic stability than that at the lower part. Based on these two results, a new design concept was developed. The procedure for this new design method is addressed in detail in this paper, and some examples of case studies using this new design concept are given.
Micro- and macro-mechanical study of compressive behavior of expanded polystyrene geofoam
Authors: Ossa A. , Romo M.P.
Published: October 2009

ABSTRACT: A series of uniaxial and triaxial compression tests was carried out in order to study micro- and macro-mechanical compressive behavior as well as some other mechanical properties of expanded polystyrene. Micromechanical behavior was analyzed by performing uniaxial compression tests on small cubic specimens. These tests were carried out using a load frame designed to be placed inside a scanning electron microscope. Using an automatic camera, micrographic sequences were taken during the loading process. These photographic sequences allowed the identification of the internal structure changes that occurred at different strain levels. Macro-mechanical behavior of expanded polystyrene (EPS) under compressive loading was investigated by means of triaxial tests on 10 cm-diameter specimens. Triaxial test results showed that the behavior was strongly influenced by EPS density, confining stress and displacement rate. Finally, based on the triaxial test results, a set of equations was proposed to estimate the compressive behavior of EPS and the accuracy of the equations was assessed by comparisons with experimental results.
Norwegian Experiences with Steel Piles to Rock
Authors: Bjerrum L.
Published: October 2009

Synopsis

The Paper reviews 25 years of Norwegian experience in the use of steel piles for foundations. The condition of soft clay overlying a hard and oftensteeply inclined rock surface which is common in Norway creates a number of problems in the design and driving of point bearing piles to bedrock. Methods of pile driving which have been evolved to ensure a satisfactory sealing of the pile point into rock are described in detail.

The problems of the buckling of piles under load and of the corrosion of steel piles in the ground are discussed in the light of recorded experience. Finally, the settlements of single piles and of buildings are discussed.The settlement of a successful single pile is found approximately equal to the elastic compression of the pile, whereas observations indicate that thesettlements of buildings are two to four times this value.

L'article passe en revue 25 ans d'expérience norvégienne dans I'emploi de pieux en acier pour fondations. Les conditions souvent rencontrées en Norvège, de l'argile recouvrant une surface rocheuse dure et souvent fortement inclinée, créent un certain nombre de problèmes dans I'exécution du dessin et l'enfoncement des pieux à pointes dans un sons-sol rocheux. Des méthodes d'enfoncement de pieux qui ont été développées pour assurer un scellement satisfaisant de la pointe de pieux dans le rocher, sont déccrites détail. Les problèmes du flambage des pieux sons pression et de la corrosion des pieux en acier dans le sol sont discutés an jour des expériences enrégistrées. Enfin, les tassements de pieux individuels et de bâtiments sont discutés. On remarque que le tassement d'un pieu individuel bien réussi est approximativement égal à la compression élastique du pieu, tandis que les observations indiquent que les tassements de bâtiments sont de deux à quatre fois cette valeur.
On The Yielding of Soils
Authors: Roscoe K. H. , Schofield A. N. , Wroth C. P.
Published: October 2009

Synopsis

Hvorslev's equation for the shear strength of clay is shown to define a surface in a space of three variables σ′, e and τ. The progressive yielding of a sample defines a loading path in this space, and the paths taken by samples in differing tests can be correlated if a boundary energy correction is applied. The final portions of all paths then lie in a unique surface, and the paths end at a unique critical voids ratio line. At the critical voids ratio state unlimited deformation can take place while σ′, e and τ remain constant.

The two concepts of the existence of such a surface and such a critical voids ratio line are verified by an analysis of results of triaxial tests on a clay. Similar tests on silt and sand also confirm the concepts, although some inaccuracy is inherent in these tests. Finally results of tests on granular media in a simple shear apparatus are presented which confirm closely the applicability of both concepts to the yielding of granular media.

On montre que l'équation de Hvorslev sur la force de cisaillement de l'argile détermine une surface dans un espace à trois variables, σ′, e et τ. Le tassement progressif d'un échantillon détermine un parcours de charge dans cet espace, et on peut établir une corrélation entre les parcours pris par les échantillons dans des essais différents sil'on applique une correction de l'énergie limite. Les parties finales de tous les parcours se trouvent alors dans une surface unique, et les parcours se terminent à une ligne critique unique des indices de vide. A l'état critique des indices de vide il peut se produire une déformation illimitée tandis que σ′, e et τ restent constants.

Les deux conceptions de l'existence d'une telle surface et d'une telle ligne critique des indices de vide sont vérifiées par une analyse des résultats d'essais triaxiaux d'une argile. Des essais similaires sur du limon et du sable confirment aussi les conceptions, quoique quelque inexactitude soit inhérente à ces essais. Finalement, on présente des résultats d'essais effectués sur des milieux granulaires dans un appareil de cisaillement simple qui confirment exactement l'applicabilité des deux conceptions au tassement des milieux granulaires.
The Use Of An Electronic Computer For Slope Stability Analysis
Authors: Little A. L. , Price V. E.
Published: October 2009

Synopsis

Sysopsis

The application of an electronic computer to stability analyses of earth dams with pore-water pressure is described. The analyses are based on Bishop's (1955)1adaptation of the Swedish method. The presentation of the data to the computer and its method of working are described and there is a brief discussion on the advantages of using the computer and possible future developments.

On décrit l'emploi d'une calculatrice électronique pour I'analyse de stabiliti: des barrages de terre á pression d'eau interstitielle.Les analyses sont fondées sur l'adaption Bishop de la m6thode suédoise.

L'on décrit ensuite l'introduction des données dans la machineet les diverses operations, et I'on discute brievement des avantages que présente I'emploi de la calculatrice, et de ses developpements éventuels.
Some Uses of Stress and Strain Invariants in the Thermodynamic Study of Soil Moisture
Authors: Coleman J. D. , Russam Kenneth
Published: October 2009

Synopsis

The Paper seeks to extend to a wider range of soil conditions the research already carried out upon the thermodynamics of soil moisture. The influence of the osmotic pressure of the salts dissolved in the soil water, the pressure in the pore air, and an applied general system of nine total stresses are briefly examined, in addition to the variables considered in earlier work. Use is made of the theory of dimensions to suggest that the invariants of both the stress and strain tensors could with advantage be employed in the study of soil moisture.

The Paper concludes with a qualitative discussion of the probable performances of a wide range of soil types in the road subgrade, and subjected to diverse climatic conditions.

Cet article cherche à étendre à une plus grande variété de conditions de sol, les recherches déjà faites sur les thermodynamiques de l'humidité des sols. En plus des variables traitées dans une étude précédente, on examine brièvement l'influence de la pression osmotique des sels dissouts dans l'eau du sol, la pression de l'air interstitiel et un système généale d'application de neuf tensions totales. On a utilisé la théorie des dimensions pour suggérer que les invariants des tenseurs de contrainte aussi bien que de déformation peuvent être utilisés avantageusement dans l'étude de l'humidite deś sols.

L' article termine par une discussion qualitative des rendements probables d'une grande variété de sols types dans les sous-sols routiers, et soumis à diverses conditions climatiques.
An Interesting Form of Failure of an Irrigation Canal
Authors: Denisov N. Ya. , Bally R. -J. , Antonescu I. P.
Published: October 2009

Synopsis

On the canals of an irrigation system situated in the Lower Danube Plain some failures have been observed in the form of cracks, settlement, and cavern formation, as well as the loss of large amounts of water.

The soil strata under the organic topsoil consists of a fine, moist, silty sand, underlain by a fat, muddy clay, very fissured. Damage was often caused by the change in local moisture conditions and from the thinning or even removal of the top soil when canals were dug.

Failures occurred as a consequence of the entrainment of fine sand by the irrigation water, which suddenly penetrated into the ground in large quantities, before entering the fissures of the underlying fat clay.

Studies made of local conditions have established where such damage can occur.Recommendations for its prevention are given in the Conclusions.

Les canaux d'un système d'irrigation situé dans la plaine du Bas-Danube ont subi de graves dégâts, tels que fissures, tassements, formation des cavernes, ainsi que des importantes pertes locales d'eau.

La stratification présente, au-dessous du sol végéal, unecouche de sable fin, silteux, à faible humidité suivi par une argile limoneuse, très fissurée, douée d'une plasticité élevée.

Les dégâts ont été favorisés par le changement des conditions locales d'humidité du sol et par l'amincissement ou même la disparition du sol végéal de l'éxecution des canaux.

Ils ont été provoqués par l'entrainement du sable fin par l'eau d'irrigation, qui a pénetré en grandes quantités à travers le sol, arrivant ensuite dans les fissures de l'argile sous-jacente.

Les études ont précisé les conditions dans lesquelles onteu lieu les dégâts, tenant compte de la situation locale, et ont établi quelques mesures pour les prévenir.
Soil Structure and Consolidation Characteristics of Black Cotton Clay
Authors: Ranganatham B.V.
Published: October 2009

Synopsis

It has been shown that the change of electrolytic environment in black cotton clay leads to very significant changes in consolidation characteristics. Also described is a method of estimating the stability of soil structure in terms of the ratio between the swelling index and the compression index. A comparison between the flocculated and orientedsystems indicates the significance of certain factors affecting the permeability of suchclays.

On y démontre que le changement de milieu électrolytique dans l'argile de “coton noir” occasionne des changements très prononcés dans les caractérestiques de consolidation. On y décrit aussi une méthode d'évaluation sur la stabilité de structure des sols selon le rapport entre l'indice de gonflement et l'indice de compression. Une comparaison entre le système floculé et le système orienté montre l'importance de certains facteurs affectant la perméabilité de telles argiles.
A Note on The Average Coefficients of Permeability For a Stratified Soil Mass
Authors: Evans H. E.
Published: October 2009

Synopsis

A general proof is given to show that in a stratified soil mass tha average coefficient of permeability for flow in a direction parallel to the bedding planes is greater than the average coefficient of permeability for flow in a direction perpendicular to the bedding planes.

On donne une preuve générale démontrant quedans une masse de sol stratifié le coefficient moyen de perméabilité pour un écoulement suivant une direction paralléle aux couches est plus grand que le coefficient moyen de perméabilité pour un écoulement suivant une direction perpendiculaire aux couches.
Undisturbed Samples of London Clay from the Ashford Common Shaft: Strength–Effective Stress Relationships
Authors: Bishop A. W. , Webb D. L. , Lewin P. I.
Published: October 2009

Synopsis

The sinking of the Ashford Common shaft by the Metropolitan Water Board has made it possible to obtain a series of undisturbed block samples of London Clay from the depths ranging from 30 to 140 ft. In this Paper are presented the results of an extensive investigation into the relationship between strength and effective stress carried out on these samples. Values of effective minor principal stress used in this series of tests have ranged from 0·2 lb/sq. in. to a little over 1,100 lb/sq. in. The failure envelope for London Clay has been shown to have a very marked curvature.

Both drained and consolidated-undrained tests have been carried out, and the significance of the stress path in the latter case is discussed. The state of stress in the undisturbed ground is estimated from the initial pore-water tension in the block samples.

Le forage du puits d'Ashford Common par le Metropolitan Water Board (Service des Eaux Métropolitain) a permis d'obtenir une série de blocs-échantillons intacts d'argile londonienne à des profondeurs variant entre 9 et 43 m. Cette communication expose les résultats d'une vaste enquête sur la relation entre la résistance et la contrainte effective qui a été faite sur ces échantillons. Les valeurs, de contrainte principale mineurs effective employées dans cette série d'essais variaient entre 0·014 kg/sq. cm et un peu plus de 77 kg/sq. cm. L'enveloppe de rupture pour l'argile londonienne a révélé une courbure prononcée.

On a fait l'essai drainé ainsi que l'essai consolidé à teneur en eau constante et on a étudié la signification du tracé de contrainte dans le deuxième cas. L'état de contrainte dans le sol intact est évalué d'après la tension initiale de l'eau interstitielle dans les blocs-échantillons.
Direct Simple-Shear Tests on a Norwegian Quick Clay
Authors: Bjerrum Laurits , Landva Arvid
Published: October 2009

Synopsis

The Paper gives a short description of a recently developed direct simple-shear apparatus. The cylindrical sample (diameter 8 cm, height 1 cm) is confined in a reinforced rubber membrane allowing vertical deformations and horizontal displacements with no change in diameter. Consolidated constant-volume shear tests showed shear strengths which were lower than those found in comparable triaxial tests. The ratio of the constant-volume shear strength to vertical consolidation pressure with the new equipment was found to be 0·18 compared with 0·29 measured in the triaxial tests and 0·13 found by vane tests in situ. The drained tests on samples consolidated at a pressure equal to the overburden in the field indicate that the structure of the clay might be stable for small shear stresses but starts to collapse at a certain critical value. This phenomenon might contribute to explain some landslides which have occurred in slopes in quick clay at a shear stress much below the ultimate drained shear strength.

Cet article décrit brièvement un appareil de cisaillement simple direct développé récemment. L'échantillon cylindrique (8 cm de diamètre, 1 cm de hauteur) est placé dans une membrane en caoutchouc renforcée permettant des déformations vertitales et des déplacements horizontaux sans changer le diamètre. Des essais de cisaillement sous volume constant sur échantillon consolidé ont indiqué des résistances au cisaillement inférieures à celles qui ont été constatées dans des essais triaxiaux parallèles. Le rapport de la résistance au cisaillement sous volume constant a la pression de consolidation vertitale s'est révélé de 0,18 avec le nouvel appareil, comparé à 0,29 mesuré dans des essais triaxiaux et 0,13 relevé dans des essais á moulinet in situ. Les essais drainés sur des échantillons consolidés à une pression égale à la surcharge sur le terrain indiquent que la structure de l'argile peut être stable pour de petits efforts de cisaillement mais commence à s'affaisser à une certaine valeur critique. Ce phénomène peut contribuer à expliquer des glissements de terrain s'étant produits sur des pentes d'argile fluide pour des efforts de cisaillement bien inférieurs à la résistance au cisaillement drainé finale.
Impervious Earth Fill For Holjes Dam
Authors: Reinius Erling , Fagerström Hans
Published: October 2009

Synopsis

This Paper describes the procedures used in the construction of the impervious core of the Höljes dam in western Sweden and the results of tests and control measures. The dam is a combined earth and rock-fill structure with a steeply sloping core of impervious earth. The height is 81 m above lowest foundation rock or 68 m above stream bed.

The high annual rainfall, about 750 mm, and low annual evaporation, about 260 mm, together with the snow-melt in this region produces a high moisture content in impervious materials, sometimes making it necessary to take special measures to ensure satisfactory compaction of the fill. At Höljes the successful drainage of the material in the borrow pit was important in maintaining construction schedules during wet summers.

Field tests were made to find out how the permeability and density were affected by stone size, stone content, layer thickness and type of compaction. Methods of extracting stones and of determining fill density were also investigated.

Cet article décrit les procédés utilisés dans la construction du noyau imperméable du barrage de Höljes en Suède occidentale ainsi que les résultats des essais et mesures de contrôle. Le barrage est une structure de remblai combiné de terre et de rochers avec un noyau très en pente de terre imperméable. La hauteur est de 81 m au dessus de la roche de fondation la plus basse ou 68 m au dessus du lit de rivière.

La forte précipitation annuelle d'environ 750 mm et l'évaporation annuelle faible d'environ 260 mm, ainsi que la fonte des neiges dans cette région, produisent une teneur en eau élevée dans les matériaux imperméables, ce qui nécessite parfois des mesures spéciales pour assurer un compactage satisfaisant du remblai. A Höljes le drainage effectif des matériaux dans la fouille d'emprunt était important pour respecter les plans d'exécution de construction au cours des étés humides. On a fait des essais sur le chantier pour découvrir comment la perméabilité et la densité étaient affectées par la dimension de la Pierre, le contenu de la pierre, l'épaisseur de couche et le type de compactage. On a aussi fait des recherches dans les méthodes d'extraction des pierres et de définition de la densité du remblai.
La Mesure in Situ Des Perméabilités Locales
Authors: Brillant Jacques
Published: October 2009

Resumé

Some 20 years ago it was considered practicable to test for water leakage during the sinking of a bore-hole, with the object of determining the physical features of the supposedly homogeneous soil and of estimating the rate of filtration.

Since that time the spreading of results and obvious discordances have been somewhat confusing.

Rather than take up a definite position, some keep asking for water tests as a routine operation.

The author considers various aspects of the problem and concludes:

Despite certain arbitrary factors which are difficult to eliminate completely from working methods, the spreading of results seems to indicate an actual heterogeneity, a factor which is moreover a deciding one in erosion phenomena, which have the most serious results.

The corrections most usually envisaged are negligible; only heterogeneous structure can explain, at least in part, the wide discordances regularly noted between overall permeability and the mean value of the measurements.

The right road to improvement is that of evaluating this discordance, which is at least partially determined by the order of magnitude and the spreading of the measurements, not that of reducing it to fit the facts, by taking advantage of arbitrary factors in the operating method.

Il y a une vingtaine d'années, on a cru pouvoir organiser le test des pertes d'eau en cours de sondage pour atteindre une caract'eristique physique du terrain supposé homogène et prévoir les débits de filtration.

Depuis, la dispersion des réultats et des écarts manifestes ont jeté le trouble dans les esprits. Pour éviter de prendre parti, on procède souvent aux essais d'eau par simple mesure de routine.

L'auteur examine différents aspects du problème et conclut:

Malgré certains arbitraires difficiles à éliminer totalement du mode opératoire, la dispersion des résultats semble bien rendre compte d'une hétérogénéité annulé, facteur d'ailleurs déterminant dans les phénomènes d'érosion qui sont les plus graves de conséquences.

Les corrections les plus couramment envisagées sont négligeables; seule l'hétérogénéité permet d'expliquer au moins partiellement les grandes différences systématiquement observées entre la perméabilité d'ensemble et la moyenne des mesures.

La voie d'une amélioration est d'éValuer cet écart, au moins partiellement déterminé par l'ordre de grandeur et la dispersion des mesures, non de le réduire au gré des circonstances, en profitant des arbitraires du mode opératoire.
The Efficiency of Horizontal Drainage Layers for Accelerating Consolidation of Clay Embankments
Authors: Gibson R. E. , Shefford Gilliane C.
Published: October 2009

Synopsis

The efficiency of drainage layers to accelerate consolidation of clay fill embankments is considered and the influence of such factors as layer thickness, length and permeability is examined. It is shown that in order to be fully effective a drain should have, typically, a permeability at least 106 times that of the surrounding clay fill, although an acceptable efficiency would be achieved with a ratio of about 3 × 104. A drainage blanket only 103 times more pervious than the fill is likely to be useless.

L'efficacité de couches de drainage pour accélérer la consolidation de remblais en argile est prise en considération et l'on examine l'influence de facteurs tels que l'épaisseur, la longueur et la perméabilité des couches. On montre qu'afin d'être complètement efficace un drainage doit posséder, d'une façon typique, une perméabilité au moins 106 fois celle du remblai d'argile environnant, quoiqu'une efficacité acceptable serait obtenue avec un rapport d'environ 3 × 104. Un tapis de drainage seulement 103 fois plus perméable que le remblai sera vraisemblablement inutile.
A Note on Sealing Piezometers in Boreholes
Authors: Vaughan P. R.
Published: October 2009

Synopsis

The situation is examined in which a piezometer is installed in a borehole which is sealed with a grout of greater permeability than the soil surrounding the piezometer. An approximate relationship between the error in piezometer reading and the relative permeabilities of the grout and ground is established for steady flow conditions. It is shown that the grout must have a permeability considerably higher than that of the ground for the piezometer reading to have a significant error.

A similar relationship is derived for the error in the determination of permeability from a constant head permeability test on a borehole piezometer. It is shown that the permeability of the sealing grout may be significantly greater than the ground permeability before a significant error results.

It is shown that in certain circumstances the filter material commonly used to surround the piezometer tip may be omitted. This facilitates the installation of a large number of piezometers at different levels in one small diameter borehole. An installation of this type at the Balderhead Dam is described.

On examine la situation dans laquelle un piézo-mètre est install´ dans un trou de sondage qui est scellé au moyen d'un mortier liquide d'une perméabilité plus grande que le sol entourant le piézomèbtre. Un rapport approximatif entre l'erreur associée à la lecture piézométrique et les perméabilités relatives du mortier liquide et du sol est fixé pour des conditions d'écoulement permanent. Il apparaût que le mortier liquide doit posséder une perméabilite considérablement plus élevée que celle du sol pour que la lecture piézom´etrique présente une erreur importante.

On déduit un rapport semblable pour l'erreur s'attachant à l'établissement de la perméabilité à partir d'un essai de perméabilité à charge constante effectué sur un piézomébtre de trou de sondage. Il apparaît que la perméabilité du mortier liquide de scellement peut àtre considérablement plus élevé que la perméabilité du sol avant qu'une erreur importante ait lieu.

Il apparaît que dans certaines circonstances le matériau de filtrage habituellement utilisé pour entourer l'extrémité du piézométre peut étre omis. Ceci facilite l'installation d'un grand nombre de piézométres à différents niveaux dans un trou de sondage de petit diamètre. On donne une description d'une installation de ce type au Barrage de Balderhead.
The Operational Strength of Fissured Clays
Authors: Lo K. Y.
Published: October 2009

Synopsis

In clays that are generally, but not necessarily, stiff fissures or joints exist with varying intensity. As the shear strengths along these discontinuities are much less than those of the intact material, they constitute planes of weakness, with the result that the strength measured depends on the size of the sample used.

Previous theories on the strength–size relation are reviewed and their limitations discussed. An equation is proposed to describe this behaviour and a method of determining the parameters involved in the equation is developed.

The results of field and laboratory tests on block samples of a stiff fissured clay, and data reported in the literature, were analysed. It was shown that the strength–size relation may be represented adequately by the proposed equation and that the strength of the clay mass operative in the field may be predicted. By taking the effect of sample size, anisotropy and time to failure into account, the conventional φ= 0 analysis, hitherto considered unreliable when applied to fissured clays, may be used for short-term stability problems if the undrained condition is satisfied.

Dans des argiles qui sont généralement, mais pas nécessairement, raides des fissures ou des joints existent en présentant une intensité variable. Comme les résistances à la rupture au cisaillement le long de ces discontinuités sont bien inférieures à celles du matériau intact, elles constituent des plans de faiblesse, résultant en ce que la résistance mesurée dépend de la taille de l'échantillon utilisé.

Les théories précédentes relatives au rapport de la résistance à la taille sont passées en revue et l'on discute des restrictions qu'elles présentent. On propose une équation pour décrire ce comportement et l'on développe une méthode permettant l'établissement des paramètres que comporte l'èquation.

Les résultats des essais effectuès sur place et en laboratoire sur des échantillons sous forme de blocs d'un argile fissuré raide, et les données fournies dans la documentation firent l'objet d'une analyse. Il apparut que le rapport de la résistance à la taille pouvait être représenté de fa¸on satisfaisante par l'équation proposée et que la résistance de volume d'argile faisant l'objet d'un examen sur place pouvait être prévue. En tenant compte de l'effet de la taille de l'échantillon, de l'anisotropie et du temps mis à arriver à la rupture, l'analyse conventionnelle φ=0, considérée jusqu'ici comme n'étant pas sûre lorsque l'on l'appliquait aux argiles fissurés, peut être utilisée pour des problémes de stabilité à court terme si la condition à teneur en eau constante est satisfaite.
Hydraulic fracturing in field permeability testing
Authors: Bjerrum L. , Nash J.K.T.L. , Kennard R. M. , Gibson R. E.
Published: October 2009

Field studies at the Dead Sea, Israel, and in Oslo have indicated that serious errors may be introduced in estimating the permeability of fine-grained clay soils using in situ tests if excessive water pressures are used, a fact already appreciated by rock and petroleum engineers. Model laboratory tests in London have confirmed that very low pressures must be employed and a mathematical analysis has been developed to indicate the factors which influence the allowable pressure. By inducing fracture the existing stresses in the ground may be estimated.

Des études sur place, effectées dans la Mer Noire, en Israel, et à Oslo, ont montré que l'on peut introduire de graves erreurs dans l'estimation de la perméabilité des sols d'argile à grains fins en se servant d'essais in situ au tours desquels la pression d'eau est excessive, un fait expérimental qui a déja été démontré par les spécialistes en mécanique des roches et an génie du pérole. Des essais sur modèle au laboratoire, à Londres, ont confirmé que l'on doit employer de très basses pressions et on a développé une analyse mathématique qui permet d'étudier les facteurs qui influencent la pressionpermissible. On peut également estimer les contraintes existant dans le sol en créant des fractures.
The invariance of Gibson's Law for a stratum on a frictionless base
Authors: Awojobi A. O.
Published: October 2009

An exact formulation is presented for the vibration of a rigid circular foundation on a stratum of Gibson soil. Specializing the governing equations for the limiting static case reveals the interesting result that Gibson's Law (1967, 1968 and 1969) of the Winkler spring model, obeyed by a linearly non-homogeneous incompressible half-space, remains true for a stratum which rests on a rigid frictionless base. This result is independent of the stratum depth. The case of vibration on a stratum adhering to a rigid base has also been considered. This has been found, even in the limiting static case, to depend on stratum depth and agrees with a result by Gibson et al. (1971) who assume ab initio that the stratum is at rest. As a check on the rather unexpected result of the invariance for a frictionless base, the static equations of Gibson et al. (1971)-who consider only the fixed base case-have been used. Both results are in agreement and they show that, under the condition of invariance, the components of rotation vanish throughout the stratum.

On présente une formulation exacte de la vibration d'une fondation circulaire rigide sur une couche de sol de Gibson. En limitant les équations de base au cas limite statique, on s'apercoit d'un résultat intéressant: la loi de Gibson (1967, 1968 et 1969) du modèle de ressort de Winkler, qui est vérifiée pour un demi-espace incompressible linéairement hétérogène, reste valable pour une couche qui repose sur une base rigide sans frottement. Ce résultat est indépendant de la profondeur de la couche. On a également étudié le cas de la vibration d'une couche qui adhère à une base rigide. On a trouvé, même dans le cas limite statique, qu'elle depend de la profondeur de la couche, ce qui est en accord avec un résultat de Gibson et al (1971), qui supposent, à priori, que la couche est au repos. Pour vérifier le résultat inattendu de l'invariance pour une base sans frottement, on s'est servi de l'équation statique de Gibson et al (1971), qui n'ont éudié que le case d'une base fixe. Ces deux résultats sont en bon accord, et montrent que, dans des conditions d'invariance, les composantes de rotation disparaissent dans la couche.
The invention and early use of compressed air to exclude water from shafts and tunnels during construction
Authors: Glossop R.
Published: October 2009

For over 100 years the application of compressed air to exclude groundwater from shafts and tunnels while under construction below the water-table and in permeable ground has been common practice. It is a most efficient expedient, for it will stabilize soils over a wide range of grain sizes, from coarse sand to fine silt, and it has been used at depths where the hydro-static head of the groundwater is equivalent to 40 or 50 lb/sq. in. In the standard texts brief reference is made to the early work of Sir Thomas Cochrane, Kt, M. Triger, John d'Urban Hughes and Dr Laurence Potts, but there has been some confusion as to the priority of their contribution to this branch of engineering practice. In this Paper the historical problems have been resolved. It has also been a matter for comment that M. I. Brunel made no attempt to apply compressed air to the Thames Tunnel which was under construction at the time when Cochrane's patent was granted. In his ‘tunnel diaries’ and among his letters to the Directors of the Thames Tunnel, now preserved in the Library of the Institution of Civil Engineers, there are references to Cochrane's invention which explain his attitude towards it.

Pendant plus de cent ans, l'utilisation d'air comprimé pour éliminer l'eau souterraine pendant la construction des puits et des tunnels sous la nappe aquifère dans des sols perméables a été une pratique courante. C'est un procédé des plus efficaces car il stabilise des sols sur une grande gamme de granulomtrie allant du sable grossier au limon fin, et il a été utilise à des profondeurs où la charge hydrostatique de l'eau souterraine est équivalente à 40 ou 50 lb/in.2 Dans les textes de référence une brève allusion est faite au sujet des premiers travaux de Sir Thomas Cochrane, M. Triger, John d'Urban Hughes, et Dr Laurence Potts, mais il y a eu confusion quant à la priorité de leurs contributions à ce secteur de la pratique du génie civil. Dans cette étude les problèmes historiques ont été résolus. Le fait que M. I. Brunel n'ait pas tenté d'utiliser de l'air comprimé pour le Tunnel de la Tamise qui était en construction à l'époque où le brevet de Cochrane était accordé, a aussi été un sujet de commentaire. Dans son ‘journal du Tunnel’ et parmi ses lettres aux Directeurs du Tunnel de la Tamise maintenant conservés à la librairie de 1'Institut du Génie Civil, il y a des références à l'invention de Cochrane qui explique son attitude envers celle-ci.