The results of a series of over 120 model tests to study the end bearing capacity of piles in layered calcareous soils are described. The tests were carried out on samples enclosed in a cylindrical testing chamber, 450 mm diameter and 450 mm high, which allowed independent control of horizontal and vertical stress in the range 25 kPa to 500 kPa. The samples consisted of a loose, uncemented calcareous sand consisting predominantly of foraminifera and mollusc micro-organisms (D50 = 0.2 mm, calcium carbonate content 92%). Into this was built a layer of the same material artificially cemented by a gypsum plaster. The layer had similar properties to naturally cemented deposits, and layers with unconfirmed crushing strengths in the range 500 kPa to 4000 kPa have been prepared. All samples were tested dry. Closed end model piles of 16mm diameter were jacked at 0.1mm/s into the sample, and continuous profiles of end bearing capacity obtained during penetration. A parametric study has been carried out to examine the effects on the bearing capacity of stress level, K0, cemented layer thickness (0.5 pile diameters to 5.0 pile diameters) and layer strength. In addition, tests have been conducted with different pile geometry, multiple cemented layers, and using dynamic installation techniques. The study has identified ranges of parameters for which brittle failure of the cemented layer occurs (low stress levels and high layer strengths) and ranges where the failure is ductile (high stresses and low layer strengths). Characteristic patterns have been observed of the variation of end bearing with position as a layer is penetrated. Examination of the samples after testing has revealed details of failure mechanisms. Simple procedures are proposed for modelling the bearing capacity of such layered systems, and some implications of the results for design methods are discussed.

The stratigraphy and sedimentology of Mesozoic carbonate platform-margins cropping out in southern Italy are investigated. New strati graphic data are presented from northern and eastern slopes of the Apennine carbonate platform, based on locallycorrelated field sections. Thin-section petrography is used to demonstrate the spatial and temporal distribution of derived lithoclasts. Results indicate that southern Apennine platforms underwent repeated erosion during Cretaceous time and possible reasons for this are discussed. Petrographic studies also provided outline sediment parageneses for slopes and platforms, with special reference to the detailed geochemistry of secondary dolomite formation on the eastern margin of the Apulian platform, whose growth is indicated by proton microprobe microanalysis to have been influenced by redox changes. The sedimentary facies and sediment geometries of Upper Cretaceous to Lower Tertiary slope sediments mapped in the Frosolone area are discussed in a case-study. Cross-sections showing geometries of key beds are presented, and depositional controls are discussed. Outcrop data suggest an Early to Middle Jurassic age of basin formation of this sector of the Lagonegro-Molise basin. A further case study from the Mesozoic slope in the Gran Sasso shows sediment geometries at reflection seismic scale, and relates them to possible depositional control by relative sea-level fluctuations. Finally, data from southern Apennine platforms and basins are combined in a tentative sequence stratigraphic framework for the Middle Cretaceous. The results of onedimensional subsidence modelling are presented in order to separate and describe the signals of local tectonics and relative sea-level fluctuations affecting the southern passive-margin of Mesozoic Tethys.

No description available.

Cette étude se situe dans le contexte industriel de l'utilisation de superplastifiants pour la réalisation de bétons haute performance. Pour mieux comprendre le mode d'action des molécules fluidifiantes nous avons utilisé un système modèle constitué de suspensions de particules de carbonate de calcium l'une commerciale et constituée de microparticules et l'autre synthétisée au LPMC et constituée de nanoparticules. L'étude a porté sur cinq molécules organiques : quatre de type polyméthacrylates greffés polyoxyéthylène (PCP) avec des longueurs de greffons différentes et un diphosphonate polyoxyéthylène : OPTIMA100. La caractérisation des grandeurs pertinentes des fluidifiants comme leurs complexations vis-à-vis des ions ; leurs degré d'ionisation, leurs tailles, leurs affinités avec le solvant ou encore leurs capacités d'adsorption sur les surfaces a été effectuée. D'importantes différences d'efficacité de ces fluidifiants vis-à-vis de la rhéologie et de la sédimentation des deux types de suspension ont été mises en évidence. Ces différences de comportements on été interprétées grâce à la caractérisation effectuée sur les fluidifiants et à la modélisation des forces interparticulaires.

No description available.

The whole Mediterranean was a site of carbonate deposition during Miocene. Unlike other Miocene basins in the Mediteranean, the importance of Mut Basin lies in its tectonically undisturbed nature that provides excellent exposures to study sequence stratigraphic architecture and carbonate sedimentology. Opening of Mut Basin began during Oligocene / carbonate deposition started during Early Miocene. The pre-Miocene rocks are characterized by (from bottom to top), 1. ophiolites and Mesozoic limestones, 2. Eocene lacustrine limestones, 3. Burdigalian fluvial sandstones and conglomerates. The carbonate deposition began in Miocene, settling on the preexisting topography. Carbonates have been deposited in a ramp setting, where several sequences formed. The ramp was partly subaerially exposed during Early Miocene due to relative sea level fall / however, no significant lowstand deposits were developed. The subsequent sea level rise caused transgressive deposits to overlie this ramp sequence. The patch reefs on this ramp exhibit a keep-up type depositional setting. As the transgression continued, the basin topography controlled the type of depositional setting. Hence, a transition from ramp to reefal margin type setting occurred. In landward direction the topographically low areas became back reef lagoonal part of this reefal margin. A mature reefal environment formed during highstand times, which is characterized by a rich coral fauna / algal flora in the basinward side. Some of the patch reefs of the ramp transformed into pinnacle reefs. Diagenetic alterations are mostly related to duration and degree of sea level fall, and therefore related to sequence boundaries. The Miocene carbonates in the study area consist of six sequences which may be used for correlation with other Miocene carbonates of the Mediterranean region.

Characterization of carbonate reservoirs by flow units is a practical way of reservoir zonation. This study represents a petrophysical-based method that uses well loggings and core plug data to delineate flow units within the most productive carbonate reservoir of Derdere Formation in Y field, Southeast Turkey. Derdere Formation is composed of limestones and dolomites. Logs from the 5 wells are the starting point for the reservoir characterization. The general geologic framework obtained from the logs point out for discriminations within the formation. 58 representative core plug data from 4 different wells are utilized to better understand the petrophysical framework of the formation. The plots correlating petrophysical parameters and the frequency histograms suggest the presence of distinctive reservoir trends. These discriminations are also represented in Winland porosity-permeability crossplots resulted in clusters for different port-sizes that are responsible for different flow characteristics. Although the correlation between core plug porosity and air permeability yields a good correlation coefficient, the formation has to be studied within units due to differences in port-sizes and reservoir process speed. Linear regression and multiple regression analyses are used for the study of each unit. The results are performed using STATGRAPH Version Plus 5.1 statistical software. The permeability models are constructed and their reliabilities are compared by the regression coefficients for predictions in un-cored sections. As a result of this study, 4 different units are determined in the Derdere Formation by using well logging data, and core plug analyses with the help of geostatistical methods. The predicted permeabilities for each unit show good correlations with the calculated ones from core plugs. Highly reliable future estimations can be based on the derived methods.

In the history of a reservoir, after the period of primary production, about 30 to 40%, of the original oil in place may be produced using a secondary recovery mechanism. Polymer injection, which is classified as a tertiary method, can be applied to the remaining oil in place. In this thesis, oil/water relative permeabilities, effect of polymer injection on end point relative permeabilities and residual oil saturations in heterogeneous carbonate reservoirs were investigated. Numereous core flood experiments were conducted on different heteroegneous carbonate cores taken from Midyat Formation. Before starting the displacement experiments, porosity, permeability and capillary pressure experiments were performed. The heterogeneity of the cores are depicted from thin sections. Besides the main aim stated above, effect of flow rate and fracture presence on end point relative permeability and on residual oil saturation and were investigated. According to the results of the displacement tests, end point hexane relative permeability increased when polymer solution was used as the displacing phase.Besides, end point hexane relative permeability increased with polymer injection and fracture presence.

This study aims to enlighten microfacies evolution and micropaleontological properties of the Tournaisian &amp / #8211 / Visean boundary in Aladag Unit (Central Taurides, Turkey). Two sections comprising dark shale and dark limestone alternations, including a fairly dolomitized part towards their top are measured. The microfacies analysis suggests a subtidal depositional environment. Foraminiferal assemblages were distinguished at Section AP and biozonation was documented. The biozonation separates the measured section into three zones, described as A, B and C. Zone A is scarce foraminifera fauna, and mainly contains Earlandia sp. Zone B is defined by appearance of a diversified foraminifera fauna and the first appearance of Lugtonia monilis (Malakhova, 1955) with Eoparastaffella sp. (morphotype 1). Zone C is defined according to the first appearance of Eoparastaffella simplex (Vdovenko, 1964) (morphotype 2) and foraminifers Laxaendothyra ex. gr. laxa. Tournaisian &amp / #8211 / Visean boundary is defined at the 60th sample, due to appearance of Eoparastaffella simplex (Vdovenko, 1964) (morphotype 2). Seven microfacies types in section AP, and six microfacies types in section PA are identified and, the intensely sampled part of the measured section AP is separated into 13 shallowing upward meter-scale cycles. These cycles, showing subtidal character are detected by both repetitions of microfacies and changes in abundance of foraminifers. A contrasting evaluation of the Tournaisian &amp / #8211 / Visean boundary of Taurides with Guangxi, South China and Dinant, Belgium is presented. The Chinese stratotype contains a diverse, more complete fauna of Tournaisian - Visean foraminifera, while the Belgium and Turkish sections are scarcer and most probably facies controlled.

The Oligocene Brac Formation is the oldest part of the Bluff Group that is exposed on Cayman Brac. Sediments of the Brac Formation were deposited on a small, open bank in shallow marine waters. Today, the formation is composed of limestone, finely crystalline dolostone, and coarsely crystalline sucrosic dolostone. The Pollard Bay member, defined herein, comprises the sucrosic dolomite that is exposed only on the south coast of Cayman Brac. Changes in sea level and subsequent groundwater chemistry mediated a complex diagenetic evolution that is responsible for the lithological heterogeneity that now characterizes the formation. Field, petrographic, and geochemical analyses indicate that dolomitization was probably mediated by normal to slightly modified seawater. Multiphase dolomite crystals represent different stages of textural and geochemical maturity, and attest to time-transgressive dolomitization processes that evolved in various hydrologic regimes through time.