Browsing by Author "Valente, Robertt"
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- 3D numerical modeling of geosynthetics for soil reinforcement: a bibliometric analysis and literature reviewPublication . Paiva, Lucas; Pinho-Lopes, Margarida; Paula, António Miguel; Valente, RoberttSoil reinforcement using geosynthetics is an efficient and cost-effective solution for a variety of geotechnical structures. Along with the increasing use of geosynthetics, there is a need to expand and enhance the design methodologies for these elements, which are still frequently based on conservative limit equilibrium approaches. In this paper, a bibliometric analysis was conducted on geosynthetic-reinforced soil structures (GRS), identifying the state of the art, research trends, and other indicators. The data were obtained from the Scopus platform and processed by VOSViewer v1.6 software. The initial search comprised 552 papers and the screening process selected 516 relevant papers from 1992 to October 2023. The study analyzed the occurrence of publications by year, keyword trends, authors, citations/co-citations, and bibliographic coupling. Then, a focus was given to 3D modeling research on geosynthetics, highlighting the dominant modeling techniques, material properties, and design challenges in GRS. The bibliometric analysis provided a crucial guideline in the identification of relevant papers and research trends, and a series of conclusions were presented regarding the 3D modeling techniques, choice of material properties, and boundary conditions.
- Geosynthetics for sustainable cities: 3D models and mechanical damagePublication . Lucas, Paiva; Lopes, Margarida Pinho; Paula, António Miguel; Valente, RoberttGeosynthetics have increasingly been used as a reinforcement material in a variety of geotechnical engineering applications (e.g., roadways, foundations, steep slopes). Reinforced soil relies on the transference of stresses from the soil to the reinforcement elements. Thus, it is key to understand how mechanical damage of the geosynthetics influences the stress-strain-time response of soil-geosynthetic interaction. This thesis includes collecting high-quality experimental data and performing laboratory tests on the deformation response of geosynthetics and soil-geosynthetic composite, before and after damage. Then, numerical tests, using the finite element method will be implemented with relevant constitutive equations. The tests will be validated using the experimental data collected. Parametric numerical tests will be performed. Finally, a general approach will be described to model common geosynthetic structures, for a more efficient use of both geosynthetics and natural resources.
- Three-dimensional modelling of in-isolation tensile response of geogrids using hyperbolic constitutive modelsPublication . Paiva, Lucas; Pinho-Lopes, Margarida; Valente, Robertt; Paula, António MiguelNumerical modelling of geogrids is a challenging task, with extruded geogrids often presenting complex geometries and nonlinear tensile response even at low strain rates. In this study, threedimensional (3D) models were developed in ABAQUS to investigate the in-isolation tensile response of extruded geogrids, accounting for a detailed geometric discretization. Hyperbolic constitutive models were used to represent the nonlinear tensile response, including fracture simulation. A benchmarking exercise was initially performed using the literature data to assess the main numerical modelling parameters for a precise and time efficient simulation. Then, a case study composed of three extruded geogrids were used to validate the model. Particular emphasis was given on the data treatment of the case study, namely with the development of a data-driven model to obtain the most representative load strain curve from experimental specimens. The modelling approach proposed in this study was capable of capturing the in isolation tensile response of extruded geogrids with good accuracy, and accounting for softening and fracture responses.