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In the previous companion paper, a modified state-surface approach was proposed to algebraically represent unsaturated soil behavior under isotropic stress conditions. The present paper proposes a general theoretic formulation for the modified state-surface approach based on the theory proposed by Fredlund and co-workers. The signs and physical meanings of the material properties, the shapes of the loading-collapse (LC) and suction increase (SI) yield curves, and the mechanisms used in the Barcelona basic model (BBM) to model unsaturated soil behavior are discussed. Some other problems, such as stress-path independency and its implication on material properties, as well as coupling effects between the LC and SI curves, are also discussed. Based on analysis, it was found that with a minor modification, the modified state-surface approach can be used to study both unsaturated expansive and collapsible soil behavior in a unified framework. [ABSTRACT FROM AUTHOR]

The authors have studied the construction-related public procurement environment in the United Kingdom to identify and analyze potential improvement strategies that may be applied in Spain. The paper comprises a comparative analysis of the environments in both countries. It focuses on recent programs to enhance the efficiency of the British administration, and includes suggestions for improving those programs and the main keys to their success. A Delphi analysis was carried out in Spain to assess, in qualitative terms, how efficiently and easily those strategies could be implemented there. The results indicate that, if implemented, many of those potential strategies would pose significant difficulties in the short and medium term. Therefore, the reasons for those feasibility problems are summarized. In any case, specific strategies used in the UK environment, explained here, could be useful for Spain and other countries with similar characteristics. [ABSTRACT FROM AUTHOR]

The extinction and recovery of Ostracoda at the Pliensbachian–Toarcian (P–T) boundary are analyzed based on a database of taxonomically revised Pliensbachian to Toarcian transition ostracod assemblages. In contrast to earlier assertions, the results of this study indicate that ostracod extinction rates were significant in comparison with other marine invertebrates. An extinction rate of 54% has been calculated for upper Pliensbachian ostracod species occurring in more than one section. Diversification took place in the latest Pliensbachian (Spinatum Zone) and early Toarcian (Tenuicostatum Zone), whereas diversity decrease occurred in the middle early Toarcian (Strangewaysi Subzone, Serpentinus Zone). This notable diversity decline in the early Toarcian corresponds to a global mass extinction time, whose peak has been documented in the Tenuicostatum Zone. Meanwhile, the ostracod mass extinction occurred within the Serpentinus Zone and was followed by radiation and recovery in the succeeding Bifrons Zone. Similar diversity changes of ostracods are observed in other European areas, although in the Cordillera Ibérica, the demise began later. Many aspects of this event are still debated, and there is no common cause or single set of climatic or environmental changes common to this event. The supposed extinction-causing environmental changes resulting from anoxia episodes are unclear and are unlikely to have been of sufficient intensity or geographic extent to cause this global extinction. In this paper, the decrease in marine species diversity is explained by a new palaeoceanographic scenario, in which a rapid global cooling episode is regarded as the ultimate cause. [ABSTRACT FROM AUTHOR]

The development of tunnelling projects under heavily populated cities has been rapidly increasing around the world during the last decades. Since tunnel construction can have disastrous effects on buildings, structures, and utilities near the excavation, construction methods have necessarily to provide maximum safety inside and outside the tunnel. To predict and correct dangerous ground movements due to the tunnelling works, the authors developed a numerical model to simulate the earth pressure balance (EPB) excavation procedure and injection to complement some deficiencies found in previous analytical or empirical subsidence estimating procedures. This model takes into account the full excavation sequence and has been validated by a large amount of monitoring data from the previous Madrid Metro extension. In the present paper, several predictive methods are used to predict the ground movements generated during a new Madrid Metro extension project consisting of 48 km of tunnel (1999–2003). At the end of the works the results will be compared with data from monitored sections placed in all five cities linked by the extension. Conclusions about the applicability and accuracy of the methods will be established with the aim of helping researchers and engineers in their future projects.Key words: ground movements, monitoring, numerical modelling and analysis, settlement, tunnels.Le développement de projets de creusage de tunnels sous des villes densément peuplées s'est accru rapidement dans le monde au cours des dernières dizaines d'années. Mais la construction de tunnels peut avoir des effets désastreux sur les bâtiments, structures et équipements près des excavations, et en conséquence, les méthodes de construction ont nécessairement progressé pour fournir un maximum de sécurité à l'intérieur et à l'extérieur du tunnel. Afin de prédire et corriger les mouvements dangereux de terrain dus aux travaux de creusage de tunnel, les auteurs ont développé un modèle numérique pour simuler la procédure EPB d'excavation et d'injection pour compenser certains défauts trouvés dans les procédures antérieures d'évaluation analytique ou empirique de l'affaissement. Ce modèle prend en compte la pleine séquence de construction et a été validée par une énorme quantité de données de mesures provenant de la prolongation antérieure du métro de Madrid. Dans le présent article, plusieurs méthodes de prédiction ont été utilisées pour prédire les mouvements de terrain générés au cours du projet de prolongation du métro de Madrid sur 48 km de tunnel (1999–2003). À la fin des travaux, les résultats vont être comparés avec les données de sections instrumentées placées dans les cinq sites reliés par la prolongation. On propose des conclusions sur l'applicabilité et la précision des méthodes dans le but d'aider les chercheurs et les ingénieurs dans leurs projets futurs.Mots clés : mouvements de terrain, mesures, modélisation et analyse numériques, tassement, tunnels.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

This paper is an analysis of the effects of forest fragmentation on wild boar, Sus scrofa, occurrence in coarse-grained fragmented landscapes in central Spain. Habitat fragmentation has been cited as one of the most important threats to species conservation. Occurrence was examined in relation to forest size, isolation, habitat quality, and region. Wild boar occurrence was mainly explained by the location of the forest fragments on the northern or southern plateau. Wild boars were more abundant on the northern plateau than on the southern plateau. In addition, wild boars are more frequent in large forest fragments adjacent to other large forests near mountains or riparian woodlands. The following variables related to size and isolation of forest fragments were quantified: fragment size, distance in meters to the nearest forest fragment, size of the nearest forest fragment, distance to the nearest forest, and distance to neighboring forests. The spatial distribution of wild boars may be affected by forest fragmentation despite their typical generalist life-history traits and potential use of agricultural areas as food habitats. These results support the idea that landscape pattern, the degree of fragmentation and grain pattern, may be a determinant of species' abundance and distribution in fragmented landscapes. Besides the effects of geographic location, this study showed a regional effect. These factors are difficult to explore in extensive studies, but a combination of non-measured habitat-quality variables such as food availability, presence of water, and heterogeneity, human pressure like hunting, poisoning, land-use management, endemic diseases, stochastic factors, and history may explain these important differences between studied regions.