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ABSTRACT: The subsoil of a large area surrounding the city of Rome (Italy) consists mainly of pyroclastic flow deposits, locally known as pozzolane. The physical and mechanical properties of these deposits are highly variable depending on depositional environment and diagenetic alteration. Quarries of pozzolana with stable subvertical open cuts as high as 20–30 metres are frequently encountered in the area south east of Rome, due to high characteristic values of effective peak cohesion and friction angle. However, cohesion may be highly variable in the deposits and it deteriorates on loading, leading to precarious conditions of stability. Sub-vertical cuts in pozzolana may also collapse due to the presence of discontinuities hidden in the rock mass, such as tension cracks at the top of the cut, or thin layers of different geological origin, formed during quiescent stages. Because the mechanical behaviour of the material at ambient stresses in the field is brittle, collapse may occur suddenly with little warning signs. The paper is a parametric study of the conditions of stability of typical cuts in pyroclastic deposits; the sub-vertical cut face at Fioranello, a quarry 20 km south-east of Rome, is used as an example. Although the degree of fissuring of the soft rock at this site is generally low and there are no major discontinuities within the rock mass, the analysis takes into account the presence of tension cracks as the triggering factor for an instability phenomenon. INTRODUCTION Pyroclastic deposits originated from the explosive activity of the Colli Albani volcanic complex (Upper Middle Pleistocene or about 500,000 years ago) form the subsoil of a large area south-east of the city of Rome. Due to their geological origin the deposits are highly heterogeneous in particle size distribution, mineralogical composition, and micro-structural features depending on different depositional environments and diagenetic alteration.
Five years passed scientific sessions, an impressive exposition of oil before the second one took place, in Lüttich, Germany, industry equipment and services was put on for the and two more before the third of such meetings was participants by a group of 364 companies. It was at the Bucharest During the meeting of the Permanent Council in Congress that the International Petroleum Commission Frankfurt, on the occasion of this Congress, it was was established as a permanent institution. Consequently, it was later industry of the world were to gather again. An innovation introduced Petroleum Congresses-was held in London, England. Based on this experience, at the Paris, France, in June of 1937. The total attendance Seventh Congress a larger number of papers were was 1,630 persons from 33 nations, and 392 papers presented in panel form, with the further difference were delivered and discussed in 70 work sessions. At that while in Frankfurt the panels were made up of this Congress, an international organization called independent papers that were not specially prepared "The Permanent Council of the World Petroleum for this purpose, at the Seventh Congress, only after Congresses" was created for the purpose of furthering suitable topics were chosen for each Panel, papers the study of the science and technology of the were requested to implement specifically each one of petroleum and allied industries on an international them. It was not until 1951 that the Third World Petroleum Congress, which had been scheduled for 1941 in 2. PRELIMINARIES OF THE Berlin, Germany, could be held. SEVENTH CONGRESS Hague, Netherlands, and a record attendance of 2,118 participants from 40 countries was registered. On June 24, 1963, at the Permanent Council's The Fourth World Petroleum Congress was held in meeting in Frankfurt, Germany, the Mexican delegation Rome, Italy, in June, 1955, with an attendance of presented a formal letter of invitation proposing 3,250 persons and the presentation of 320 technical Mexico City as the venue for the Seventh Congress. The Council members were also invited to hold their In May, 1959, coinciding with the centennial of the next meeting in Mexico, as guests of the Mexican United States oil industry, the Fifth World Petroleum National Committee in January, 1964.
Synopsis Samples of Italian crude oils, drawn from producing wells or seepages distributed throughout the whole Peninsula and Sicily, have been analysed. The principal characteristics and the U.O.P. characterization factors are given for all of them, while for most of them a complete analysis has been carried out according to the U.S. Bureau of Mines method, leading to calculation of the Correlation Index and the establishment of the base of the oil. A few ring analyses have also been made. Finally, the correlation between the crude oils and the horizons from which they originate has been discussed. Résumé Des échantillons de pétroles bruts italiens provenant de puits productifs ou de suintements ré- partis à travers toute la péninsule et la Sicile ont eté analysés. Les principales caractéristiques et les facteurs de caractérisation U.O.P. sont donnés pour tous les échantillons; pour la plupart d'entre eux une analyse complète a été faite suivant la méthode du, Bureau of Mines" qui conduit à calculer l'indice de corrélation et à établir la base de l'huile. Quelques analyses de chaines fermées ont été également exécutées. L'auteur termine par une discussion au sujet de la corrélation entre les pétroles bruts et les horizons d'où ils proviennent. The scope of this paper is to compare various crude oils produced in different parts of Italy, to emphasize their similarities and differences, and to find out if relations exist between the chemical and physical characteristics of the oils and the horizons or depths they are derived from. Azienda Generale Italiana Petroli (A.G.I.P.), Rome, Italy. In carrying out the analysis of the various samples of crude oils we have followed the Bureau of Mines method, outlined by A. J. Kraemer (i)*, which divides each oil by distillation into 15 fractions. The data obtained have been set forth in various tables, in which we have given the general characteristics for each oil: gravity, sulphur content, colour and viscosity, and the percentages, gravities and viscosities of the various fractions obtained by atmospheric and 40 mm. pressure distillation. In the summary which is at the foot of each table, we have calculated approximately the percentages of gasoline, kerosine and other products according to the following criteria: light gasoline is the fraction that distils below 100°C; total gasoline and naphtha, is the sum of the fractions that distil below 2OOOC and have a specific gravity not higher than 0.825 at 60°F; in compliance with convention, we have called kerosine those fractions boiling higher than 2OOOC which have a specific gravity not exceeding 0.825 at BOOF. Since the Italian crudes examined are mostly naphthenic, there is only a small percentage, if any, that complies with these characteristics; in general, the specific gravity of the fractions distilling above 200' is too