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In addition to the intensity of precipitation, the different hydraulic and mechanical properties of a soil hill can also be responsible for landslides. More specifically, the same rainfall amount can trigger or not trigger a mass movement depending on its characteristics. This issue represents a great geotechnical hazard in mountainous regions such as Brazil, Italy, South Africa, Japan and Hong Kong. The understanding of each of the key factors involved in a rainfall-triggered landslide can be deepened and also quantified. Thus, this research defines, through a numerical model, which parameters are the key factors involved in slope stability. A homogeneous and unsaturated hill was studied. Its different hydraulic and mechanical properties were varied. Geometry and mechanical parameters were shown to exert the greatest influence on stability. Hydraulic parameters, for the same amount of rain, showed a lower influence. The fitting parameters of the soil–water characteristic curve of the materials had a low impact on stability when compared to other parameters assessed. Our conclusions can help future laboratory and field studies to focus more on the accuracy and confidentiality of the key parameters. The results are also important as they give direction to studies related to precipitation threshold definition.

Abstract One of the methods to minimize the negative impact caused by inadequate disposal of Water Treatment Plant Sludge (WTPS) is to mix it with the soil, applying the material in engineering works. In this research, the objective was the use of WTPS for soil stabilization purposes, verifying the improvement of the characteristics and properties with 0%, 15%, 30% and 50% of sludge, for application in the base and sub-base layers of road pavements. Characterization, compaction, permeability, Resistance to Simple Compression (RCS), and California Bearing Ratio (CBR) tests were carried out. However, none of the mixes met all the necessary requirements for use in the pavement layers, but it is concluded that there was an increase in the RCS, CBR and impermeability of the mixtures compared to the reference mixture (100% soil). The RCS increased 142.75% of the soil for a blend with 30% sludge, CBR increased 76.52% of the soil for mixture with 50% WTPS, and the permeability of blends with 15%, 30% and 50% sludge was lower than then with only the soil. These results show that these mixtures can be useful for other types of applications in Geotechnics, being able to contribute to the sustainable destination of WTPS.

Foi estudado, através do Método dos Elementos Finitos, o comportamento de fundações superficiais assentes em sistemas de dupla camada, sendo a superior artificialmente cimentada, com uma largura igual a três vezes o diâmetro da fundação. Sendo H a espessura de solo cimentado e D o diâmetro da fundação, foram feitas diversas simulações para as várias relações H/D (desde zero até 4,0). Depois de confirmada a influência da relação H/D na resposta carga x recalque de fundações superficiais, foi feita uma análise paramétrica após a qual é proposta uma nova metodologia de dimensionamento de fundações superficiais assentes em sistema de dupla camada, sendo a superior cimentada. Finalmente, a capacidade de suporte de fundações superficiais assentes em camadas cimentadas foram simuladas com sucesso através da nova metodologia apresentada. Para a prática da engenharia o método proposto, através de curvas carga-recalque, fornece boas previsões para a obtenção da capacidade de suporte de fundações superficiais.