Geologie des barrages dans les regions karstiques de grece quelques considerations generales—Quelques cas particuliers

Carbonate rock distribution state, as well as structural and paleogeographic influence on the karst and on hydrogeological bassin distinction are briefly discussed, in relation to civil work construction. Need for covering wide areas during hydrogeological studies for water-tightness problems identification is stressed and confrontation measures for water-tightness problems are illustrated, based on experience from certain particular cases.     

Contribution a la reconnaissance des massifs rocheux de fondation de barrages (Exemples de sites pyrénéens,France)

A rotation of the regional direction of compression in course of time is pointed out from the study of some dam sites from Pyrenees. The geological history and the fracturation kinematics allow to deduce an ancient direction of compression NE-SW corresponding to the sinistral transforming process which gave rise to the major structures of Pyrenees. Geotechnical tests (seismic velocities, flat jack tests, dilatometer tests, Lugeon tests) and seismology show a present compression trend NW-SE, different from the previous one, and permit to construct the mechanical and hydraulic anisotropies of the investigated sites. So, the geodynamical and structural background must be taken into account when setting the tests for a dam foundation-block prospection.     

La Geologie de l’Ingenieur au site de la gare souterraine Saint-Georges,a Liege (Belgique)

Resume Au site de la gare souterraine Saint-Georges du future métro de Liège, les études géologiques, hydrogéologiques et géotechniques ont été réalisées conjointement avant l’établissement de l’avant-projet. Elles ont permis de déterminer la constitution détaillée de la plaine alluviale et du bed rock, l’hydrogéologie dans les alluvions et le terrain houiller, les propriétés géomécaniques des roches présentes et leur modification dans les massifs saturés en eau. La confrontation de toutes les données recueillies permet non seulement d’établir de meilleures corrélations entre les divers phénomènes examinés: nature, structure, texture des roches, allure et comportement des nappes aquifères, qualité des matériaux, … mais encore, par la synthèse, de fournir aux ingénieurs de projet une somme intéressante de renseignements quantitatifs propres au site investigué et à l’ensemble des conditions qui y règnent.

---

At the site of the underground station of the intended Metro of Liège the geological, hydrogeological and geotechnical investigations have been carried out jointly before the realization of the preliminary plan. They have enabled to determine the detailed geological constitution of the alluvial plain and of the bed-rock, the hydrogeology in the alluvial deposits and in the coal measures, the geomechanical properties of the rocks and their modifications in the massives saturated with water. The comparison of all the data gathered enables not only to obtain better correlations between the different phenomena investigated as nature, structure, texture of the rocks, aspect and behaviour of the underground water levels, quality of the materials, and so on, but also, through the synthesis, to supply the engineers of the plan with a useful amount of quantitative information which is peculiar to the site investigated and to the whole of the conditions existing in it.

---

---

Ingénieur civil des mines et ingénieur géologue — Professeur à l’Université de Liège.

---

Ingénieur civil des mines et ingénieur géologue — Premier assistant à l’Université de Liège.

---

Ingénieur civil des constructions — Assistant à l’Université de Liège

---

Ingénieur géologue.     

Quelques exploitations statistiques d'un fichier informatique de mouvements de terrain

A French computer data base on soil and rock failures has been recently developed and some results obtained from the data are presented: frequency of different types, spatial and temporal distribution, statistical data about victims, various causes of occurrence, types of technical solutions used, etc. The influence of the present sampling bias is discussed.     

Importance de la petrographie dans l'approche des mecanismes de la reaction alcali-granulat

Résumé Dans les bétons, les granulats subissent une agression liée à l'hyperbasicité du milieu. Cette agression connue sous le nom de réaction alcali-granulat peut être limitée ou au contraire se développer jusqu'à la ruine des ouvrages. L'évolution de la réaction dépend de plusieurs facteurs: la nature pétrographique, l'accessibilité, des minéraux, aux solutions agressives et surtout l'état d'altération préexistant de la roche. Ces deux derniers paramètres pouvant être approchés par les mesures de surfaces spécifiques et visualisés par les observations pétrographiques en microscopie optique et électronique. Nous présentons des exemples montrant le développement de la réaction et son évolution suivant la nature pétrographique et le degré d'altération des granulats utilisés.

---

Importance of the petrographic analysis for approaching the mechanisms of alkali-aggregate reaction

Aggregates used in concrete are sub mitted to an etching due to the hyperbasic medium. This chemical reaction is known as the alkali aggregate reaction and can be either limited or sometimes so well developed that it lead to the ruin of the whole structure. The evolution of the reaction depends on several factors: the petrographic characteristics, the penetration of aggressive solutions into the aggregates and above all the state of alteration of the original rock. The two last mentioned parameters can be approached by means of specific area measurements and visualized by petrographic analysis in optical and electronical microscopy. The examples presented in the paper point out the development of the reaction and the evolution of the phenomenon un function of the petrographic properties and of the state of alteration of the aggregates used.

     

Determination de la permeabilite des alluvions a partir de la prospection electrique

Bulletin of Engineering Geology and the Environment - Les nombreuses reconnaissances par sondages électriques, réalisées lors de ces vingt dernières années, en vue...     

拉·维莱特公园

1983年,伯纳德·屈米建筑师事务所从470支团队里脱颖而出,赢得了巴黎拉·维莱特公园国际设计竞赛.该项目同新法国国家图书馆、卢浮宫金字塔、拉德芳斯新凯旋门和阿拉伯世界研究中心等项目一样,是当时法国政府主持的几大工程之一.那次设计竞赛的目标是表达时代愿景,推动项目所处的巴黎关键区域未来经济和文化的发展.     

Etude de l'evolution de la qualite des eaux de riviere

In France, the creation of a “Ministère de l'Environnement et du Cadre de Vie” and “Agences Financieres de Bassin” has made it possible to obtain information on the water quality of rivers and on the measures necessary to improve water quality. Particularly in the Adour-Garonne Basin, much information is now available. The methodology needed to draw conclusions concerning the quality of the rivers and to show the effectiveness of control measures has been developed.This method has been tested in two catchments (Fig. 1): L'Adour (15,000 km²) and La Dordogne (24,000 km²). The steps that were necessary before this method could be used were: critical assessment of the available data; identification and measurements of pollution sources. This called for the collection of information, annual statistics for each sampling station and information concerning the value and importance of measured parameters.Detailed information is available from 1971 and 1976 and this is shown by maps and graphical representations of the variations in the value of different parameters (Fig. 2).Statistical analysis has also been carried out on the information available for the period 1971–1976.Two methods were used: analysis of the principal components, the method most used being shown by Figs 3 and 4 and the “STATIS” method developed recently which treats the whole data “At 3 indices” (Fig. 5).Research has been carried out on the causal relations between the water quality and the sources of pollution.A simple graphical method is proposed to explain the effect of a strongly preponderant pollutant source. It allows easy visualisation of the change in the relationship between two series of variables (Fig. 8).In general cases of several sources of pollution a simplified method using BOD exclusively has been developed. It consists in comparing the values measured in the river and the estimates obtained from inflows of various sources and those from upstream basins (Fig. 9).The application of this method has made it possible to distinguish local or general tendencies in reference to the intervention realised by the “Agence Financiere de Bassin”.Attention has been given to the variations obtained between laboratories and research information and the necessity to extend application of the statistical method to parameters other than BOD₅.Comparable action is being taken for the whole basin of the Rhone (French). The information obtained for “L'Adour and La Dordogne” has led to a study not only of the concentration of pollutants but two types of flow, with flow measurements and concentration being taken into account in order to eliminate hydraulic effects.     

Etude physicochimique de la chloration de l'eau de mer artificielle

Inorganic reactions occurring during ammonia-free sea-water chlorination have been considered. Experiments have been carried out in artificial or UV-photooxidized sea-water in order to avoid slow reactions of chlorine and bromine with organic compounds in sea-water. Results obtained either from bromine determination, using phenol red as a reagent, or from electronic absorption spectra of chlorinated sea-water show a fast and quantitative oxidation of bromide to hypobromite and hypobromous acid. No bromate formation was detected in our experimental conditions.     

Application de la teledetection a la recherche de sites d'exploitation de granulats et a l'etude de leur impact sur l'environnement

A statistic sampling of publications concerning “aggregates” prospecting and environment impact studies shows that remote sensing is not so often used, contrarily to what heppens generally in the geological field. Which can be the reasons of that under-use?

- pecularities and traditions in prospecting?

- redundency of the results of remote sensing studies with the result of other methods?

- inadequation or underperforming of remote sensing in the peculiar field of “aggregates” prospecting.

In a first part, that note defines what seems to be the most common wishes of the users concerning remote sensing. In a second part, the various tools of remote sensing are described and their performances evaluated. In a third part, a comparison between the tools and the needs of the users try to evaluate the adequation of remote sensing. After some considerations about environmental impact studies the conclusion shows that Remote Sensing, even if not able to solve all the problems, offers to the users a great variety of usefull tools which, combined with other methods, give valuable results in efficiency and cost-effectiveness.