The development of progressive failure in slopes is a poorly understood process, and relatively few advances in terms of the mechanics of the development of failure have been made since 1967. However, advances in the understanding of the development of fractures in brittle materials provide new insights into landslide mechanics. In addition, the link between the deformation mechanism and movement type allows interpretation of displacement records to determine the mechanisms acting within a slope. This paper utilizes these insights into deformation processes, combined with “reinflation” stress-path triaxial experiments, to propose a new model for the development of a progressive, first-time failure within a slope. This model is able to explain the development of failure when the factor of safety is greater than unity, the existence of “Saito” linearity (a linear trend when the reciprocal of velocity prior to failure is plotted against time) during tertiary creep, and the development of failures during periods of apparently increasing normal effective stress

Synopsis Ignition loss, liquid limit and specific gravity have been measured on 28 samples of peats and clays from the coastal flats near Avonmouth, from the Fens near King's Lynn and from Cranberry Moss, a small raised bog in Co. Durham. The organic contents of nine of these samples have been determined and, for comparison, tests are reported on three inorganic clays from other sites. The investigations have shown that for peats and organic clays (containing more than about 10% organic matter) the ignition loss is a useful index property which can be correlated closely with organic content and specific gravity and, to a lesser degree, with liquid limit. It is also shown that 550°C is a suitable ignition temperature and that little advantage is gained by adopting temperatures lower than 105°C for determining the dry weight of peats. Ignition losses of the materials tested range from 3 to 99%. La perte au feu, la limite de liquidité et le poids spécifique ont été mesurés pour 28 échantillons provennant des tourbières côtières près d'Avonmouth, des Fens près de King's Lynn et de Cranberry Moss, une petite tourbière soulevée de Co. Durham. La teneur en matières organiques de neuf de ces échantillons ont été déterminées, et, pour comparaison, des essais sont décrits pour trois argiles non-organiques provenant d'autres localités. La recherche a montré que pour les tourbes et argiles organiques (contenant plus qu'environs 10% de matières organiques) la perte au feu est une propriété caractéristique utile qui correspond étroitement avec la teneur en matière organique et le poids spécifique, et, à un degré moindre, avec la limite de liquidité Il est aussi montré que 550°C est une temperature adéquate pour mesurer la perte au feu, et que peu d'avantages sont obtenus en adoptant des temperatures moindres que 105°C pour déterminer le poids set de tourbes. Les pertes au feu pour les matériaux considérés sont comprises entre 3 et 99%.

No abstract

The paper describes a field experiment in which a 9 m deep cut slope in Gault Clay was brought to failure by pore pressure recharge. The geology of the site is described and the procedures used to form the slope are explained. A novel feature was the use of low-friction panels at each end of the study section to form isolation trenches and thus encourage primarily two-dimensional displacements. The site was extensively instrumented using piezometers, inclinometers and surface wire extensometer lines. The system used for the pore pressure recharge is described in detail. This paper also describes the laboratory testing programme performed as part of the project and discusses instrument performance, including key results and observations drawn from the experiment. It was found that the failure of the slope took place as a result of a progressive failure mechanism, with movements initiating at the toe of the slope at an early stage in the experiment. There is some evidence that a similar progressive failure mechanism also developed from the crest of the slope. An important feature of the experiment is the detailed information obtained on slope movements throughout the period up to and beyond failure. Some results from limit equilibrium analyses are presented, which indicate that significant displacements occur even when the factor of safety is well above unity. L'article décrit une expérience sur le terrain qui a consisté à induire la rupture ďun talus remanié de 9 mètres dans de &caronlargile Gault sous ľeffet de la recharge de la pression ďean interstitielle. Les auteurs décrivent la géologie du terrain et expliquent les méthodes utilisées pour former le talus. Une innovation a consisté à utiliser des panneaux à faible coefficient de frottement à chaque extrémité la section à ľétude pour former des tranchées ´isolement et, donc, favoriser des déplacements surtout bidimensionnels. Un grand nombre &acutelinstruments ont été utilisés: piézomètres, inclinomètres et extensomètres à câblage saillant. Le système utilisé pour la recharge de la pression ďeau interstitielle est décrit en détail. ľarticle décrit également le programme ďessais en laboratoire exéé dans le cadre de cc projet et examine la performance des instruments, y compris les principaux résultats et les observations faites à partir de cette expérience. On a constaté que la rupture du talus a éé progressive, commençant au pied du talus pen après le début de ľexpérience. Certaines indications font penser qˇun m&acutelcanisme semblable de rupture progressive a également eu lieu au sommet du talus. Un aspect important de cette expérience est ľinformation détaillée obtenue sur les mouvements du talus pendant toute la période qui a préé la rupture, ainsi qˇaprès la rupture. ľarticle présente certains résultats des analyses ďéquilibre limite qui indiquent que ďimportants déplacements se produisent, même quand le coefficient de sécuré est bien supérieur à ĺunité.

No abstract

No abstract

Artículo de publicación ISIA new data set of landslides that caused loss of life in Latin America and the Caribbean in the 10-year period from 2004 and 2013 inclusive has been compiled, providing new insight into the impact of landslides in this key part of the world. This data set indicates that in the 10-year period a total of 11 631 people lost their lives across the region in 611 landslides. The geographical distribution of the landslides is highly heterogeneous, with areas of high incidence in parts of the Caribbean (most notably Haiti), Central America, Colombia, and southeast Brazil. There is significant interannual variation in the number of landslides, with the El Niño/La Niña cycle emerging as a key control. Our analysis suggests that on a continental scale the mapped factors that best explain the observed distribution are topography, annual precipitation and population density. On a national basis we have compared the occurrence of fatality-inducing landslide occurrence with the production of locally authored research articles, demonstrating that there is a landslide research deficit in Latin America and the Caribbean. Understanding better the mechanisms, distribution causes and triggers of landslides in Latin America and the Caribbean must be an essential first step towards managing the hazard

Abstract. A database of landslides that caused loss of life in Latin America and the Caribbean in the period from 2004 and 2013 inclusive has been compiled using established techniques. This database indicates that in the ten year period a total of 11 631 people lost their lives across the region in 611 landslides. The geographical distribution of the landslides is very heterogeneous, with areas of high incidence in parts of the Caribbean (most notably Haiti), Central America, Colombia, and SE. Brazil. The number of landslides varies considerably between years; the El Niño/La Niña cycle emerges as a major factor controlling this variation, although the study period did not capture a large event. Analysis suggests that on a continental scale the mapped factors that best explain the observed distribution are topography, annual precipitation and population density. On a national basis we have compared the occurrence of fatality-inducing landslide occurrence with the production of research articles with a local author, which shows that there is a landslide research deficit in Latin America and the Caribbean. Understanding better the mechanisms, distributions causes and triggers of landslides in Latin America and the Caribbean must be an essential first step towards managing the hazard.