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Gravity retaining structures in gabion walls were built in the outdoor area of a shopping centre in the city of Manaus, State of Amazonas, Brazil. When the project was about half-way completed, horizontal displacements began to show excessive ‘bulging’, causing the stoppage of construction. Later studies revealed that the original geometric sections did not meet the requirements of internal, external and global geotechnical stability. Hence, it was necessary to study some alternatives to circumvent the problem. The fastest and most economical alternative proved to be increasing the cross-section of the walls, through the excavation of the backfill. The reconstruction of the walls and subsequent backfill compaction were performed step by step. The new cross-sections of the walls improved their theoretical and constructive stability, and this was proven by subsequent monitoring of horizontal and vertical displacements. It was found that the largest horizontal and vertical displacements of the gabion wall were about 20 mm and 11 mm, respectively.

This dissertation deals with an analysis by comp arison o f results obtained with piles submitted to axial uplifi foreces using sevcral prediction methods of ultimate loads. The pile tests were performed in the Experimental Si te o f the Departament o f Geotechnical Engineering of USP/São Carlos, on bored, hammed and Strauss pile types, with diameters varying from 0,20 to 0,32 m and 6 to 9 m long. It was observed that the methods that took into account the pile-soil int erface failure yeld ed better results. Moreover, the pile-soil interface colapsibility was analyzecl, once the shaf1. of th e studied piles were embedded in soil whose structu re are truly collapsiblc. For this, pile testings were perfonned both in the natural soil cond itions and soakcd cluring 48 h for working load. Collapse was observed in the pile-soil interface in five piles. for three o f them (two o f which were bored and one hammed) the failure took place with working loads under 48 h soaking time; in two others, the fai lure, occured after 48 h soaking time with loads equivalents to 60% and 78% of natural soil's ultimate loads, respectively.

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A grande maioria dos estudos sobre a análise da capacidade de carga de fundações tem se baseado no trabalho de 1920 do professor Ludwig Prandtl intitulado “Über die Härte plastischer körper” (sobre a dureza dos corpos plásticos). No entanto, não é comum encontrar referências que apresentem as diferentes considerações por trás da proposta original. Como, por exemplo, que o método exposto é de origem teórica, sem validação empírica, não sendo formulado nem para solos, nem para fundações, pois seu objetivo era avaliar a dureza de um material sólido, determinando as tensões que produzem a sua plastificação total. Em vista disso, apresenta-se uma versão rigorosa do artigo original completo de Prandtl de 1920, adaptado do alemão para o espanhol, e, posteriormente, do espanhol para o português, o que se espera contribuir para o conhecimento dos princípios, considerações e limites de validade, da amplamente conhecida Cunha de Prandtl, que representa um dos pilares dos métodos para o dimensionamento geotécnico de fundações rasas.