CASE STUDIES OF STONE COLUMNS IMPROVEMENT IN SEISMIC AREAS
Soil improvement with stone columns is often implemented in seismic areas in particular as a countermeasure against liquefaction. The efficiency of stone columns can be explained by the compaction effect during their execution, by the reduction of the seismic stress on the soil, and by their draining effect as well. A historical evolution of the first realisations is presented, followed by an inventory of the observed performance of such systems in seismic conditions. Then, recent applications of stone columns combined with pile foundations are presented. Key-Words: seismic area, stone columns, liquefaction, case study, pile foundation.
Liquefaction of Cohesive Soils
Liquefaction of sand, clean or with some fines content, has been extensively studied over the last three decades and is currently a phenomenon reasonably predictable. The study of cohesive soils behavior during and immediately after cyclic loading is especially difficult because of their structure variability and the major influence of structural characteristics on dynamic properties, which makes testing of reconstituted samples of little interest in evaluation of natural deposits. There are several categories of cohesive soils potentially liquefiable, which are considered in this paper: clayey silts or silty clays of low plasticity meeting the Chinese Criteria; highly sensitive clays; collapsible loess. Data from literature for better understanding of their susceptibility to liquefaction (triggering, post-cyclic strength) are summarized.
Anaesthetic aspects of bronchial fistula.
SINCE the term bronchial fistula can, from the practical point of view, be applied to any abnormal connection between the inside of the intrathoracic respiratory system and the outside, it includes a very wide assortment of cases. Fistulae vary in their acuteness and duration from a few minutes up to thirty years or more (Huizinga and Smelt, 1950), and in their consequences from the rapidly fatal to the almost insignificant. Although the anaesthetic management of these cases falls mainly within the province of those working in specialized units, any anaesthetist may be caught unawares from time to time. Quite apart from this consideration the subject is well worth discussing because of its intrinsic interest and because it has probably called for as much anaesthetic ingenuity and resourcefulness as any other subject within the specialty.