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Projeto de investigação
GeoBioSciences GeoTechnologies and GeoEngineering
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Evaluation of the potential use of water treatment sludge (WTS) as a waterproofing material for waste containment earthworks
Publication . Marchiori, Leonardo; Studart, André; Morais, Maria Vitoria; Albuquerque, António; Cavaleiro, Victor
Industrial wastes’ incorrect disposal
can cause groundwater and soils contamination.
In this aspect, the water treatment sludge (WTS)
appears as a potential residue to be valorized within soils in order to enhance wastes’ stabilization while mitigating its environmental
impacts. Therefore, geotechnical and chemical evaluations were conducted for assessing
WTS’s potential as a waterproofing agent for earth works, considering their impacts on the
properties of the analyzed clayey soil for assessing possible soil’ reinforcement through a
further investigation. Found results on the WTS characterization have shown a high percentage
of fines, which contributes for the reduction of the soil’s plasticity. In addition, its chemical
composition is compatible with pozzolanic characteristics while being possible to associate
the analyzed WTS with materials already used in earth works. These results indicate a solid
beginning for a complete characterization of the WTS and its stabilization within soils as they
indicate possible reinforcement of clayey soils and use for liners application, which have yet to
be confirmed by in-depth investigations around resistance and permeability properties.
GIS-based inventory for safeguarding and promoting Portuguese glazed tiles cultural heritage
Publication . Santos, Bertha; Gonçalves, Jorge H. G.; Almeida, Pedro G.; Martins-Nepomuceno, Ana M. T.
Innovative, non-invasive, digital, and cost-effective instruments for systematic inventory, monitoring and promotion are a valuable resource for managing tangible and intangible cultural heritage. Due to its powerful and effective inventory and analysis potential, which allows supporting central and local entities responsible for cultural heritage management, Geographic Information Systems (GIS) have proven to be an appropriate information technology for developing these kinds of instruments. Given the above, this work aims to introduce a GIS-based instrument to support inventorying, safeguarding, tourism, and cultural promotion of the traditional Portuguese glazed tile (‘azulejo’, in Portuguese) to raise general awareness of the importance of this unique Portuguese heritage. To the best of the authors’ knowledge, there is no other instrument available with inventory and safeguarding management functions that is accessible and affordable, developed to be used at a municipal level and that contributes to the enrichment of the cultural and tourist information. Information from 70 tile works located in the Portuguese city of Covilhã was used to test the proposed GIS tool, resulting in a georeferenced alphanumeric, graphical, image and drawing inventory and in three pedestrian routes for touristic and cultural heritage promotion. The results were validated by both the research team and the municipality of Covilhã, foreseeing its expansion and daily use in the management of the heritage
of the traditional Portuguese glazed tile. The proposed instrument can be replicated in other locations and easily implemented and managed by municipalities or institutions dealing with the protection of cultural heritage.
Mechanical and hydraulic long-term behavior for an experimental compacted liner embankment
Publication . Marchiori, Leonardo Perelló; Cavaleiro, Victor Manuel Pissarra
Mechanical and hydraulic performance, as compaction, consolidation, and
permeability, play an important role in the design and construction of earthworks. A
bad dimensioning of this magnitude can lead to major disasters, making structures
unfeasible, losing resources and even lives. This work looks to correlate quick tests of
soil mechanics with parameters that are difficult to obtain - in situ and laboratory
tests -, either because of lack of resources or the access in some unexplored areas.
An experimental embankment located in Penalobo, Guarda (Portugal) was chosen to
perform in situ tests and sampling for laboratorial tests. The tests for geotechnical
characterization – specific gravity, Atterberg limits, particle size distribution, Normal
Proctor compaction, soil density gauge, and gamma densimeter -, mechanical behavior
– free expansibility, one-dimensional oedometric consolidation, consolidated
undrained triaxial shearing, plate load test, dynamic penetration lightweight, and
heavyweight, and cone penetration test -, chemical composition – x-ray diffractures,
fluorescence, scanning energy microscopic images, cation exchange capacity, and pH
-, and hydraulic conductivity through falling head permeameter permitted to
correlate several parameters.
Results characterize the soil as a typical granitic soil, a well-graded sand without
plasticity classified as A-1-b according to AASHTO, specific gravity of 2.55, with
optimal compaction following w = 14.0% and ?d = 1.86 g/cm3
. Mainly composed by
quartz, kaolinite, and muscovite, along with high amounts of SiO2 and Al2O3, besides
lower percentages of NaO2 and Fe2O3, also showed pH = 6.0 and cation exchange
capacity = 17.0 meq/100g. The soil has high free expansibility, although low
oedometric compressibility when compacted, effective internal friction angle is
around 35º and has no cohesion.
Several rounds of tests were made for this evaluation, and since the site is studied
for over ten years, another analysis on behalf of long-term behavior of the structure
was carried out. Long-term behavior analysis and parameters correlations were
developed around compaction characteristics within Normal Proctor, soil density
gauge and gammadensimeter results; direct and indirect hydraulic conductivity
through oedometer and permeameter laboratorial tests; drilling tests relationship
among dynamic penetration lightweight, and heavyweight, standard penetration test, and cone penetration tests; in addition to laboratorial oedometer and in-situ plate
load test analysis the consolidation of the embankment liner.
Evaluation of Pedestrian Crossing Accidents Using Artificial Neural Network
Publication . Santos, Bertha; Gonçalves, Jorge; Amin, Shohel ; Vieira, Sandra Cristina Gil ; Lopes, Carlos Manuel Valença Martins
Most of European cities face increasing problems caused by excessive traffic of conventional fuel-based transport modes. To reverse this situation, sustainable urban mobility policies have been promoting soft modes of transport, such as walking. Despite the advantages of walking in reducing traffic congestion and pollution, cities have not always evolved to accommodate the needs of pedestrians. According to the European Commission, in 2020, 20% of road fatalities in the European Union (EU) and 21% in Portugal were pedestrian. Pedestrian fatality rates per million population was 9.7 for all EU countries and 13.1 for Portugal. In European and Portuguese urban areas, 36% and 27% of the fatalities were pedestrians’ and 49% and 56% of all pedestrian fatalities were elderly’s (respectively). In pedestrian infrastructures, crossings are considered the most critical element due to conflicts between vehicles and pedestrians. It is then essential to identify and minimize risk factors that increase the probability of accidents in these locations. The proposed work intends to assess this challenge by using Artificial Neural Network (ANN) to create pedestrian severity prediction models and identify road and pedestrian risk factors for accident occurred in or near urban crossings. The official Portuguese database on run over pedestrian accidents occurred between 2017–2021 was analyzed with ANN considering two scenarios: pre-Covid-19 and during Covid-19 period. Results obtained demonstrate that the use of ANN can promote a proactive infrastructure management, suggesting that crossings traffic lights operation, lighting, shoulders and pavement conditions, high speed limits (51–90 km/h) and pedestrians moving in soft modes are critical factors.
Statistical analysis of an in-vehicle image-based data collection method for assessing airport pavement condition
Publication . Feitosa, Ianca Teixeira ; Santos, Bertha; Gama, Jorge; Almeida, Pedro G.
This study presents a comprehensive comparative statistical analysis to validate a novel in-vehicle image-based method for collecting pavement condition data in airport environments. It highlights the method’s potential to address key challenges faced by airport pavement managers, such as the need for continuous maintenance and the demand for fast, effective, and reliable inspection procedures. The in-vehicle system integrates laser scanning systems, image capture, and georeferencing devices to collect pavement distress data, and its accuracy and reliability are evaluated statistically. The primary objective is to validate and enhance this novel inspection approach, which shows strong potential as an effective alternative for comprehensive pavement evaluation, enabling continuous, rapid monitoring and the analysis of trends. Validation was performed by means of a detailed statistical comparison of pavement distress density on the main runway of Amílcar Cabral International Airport, Sal Island, Cape Verde, based on data collected using the proposed in-vehicle and the traditional on-foot inspection methods. Non-parametric repeated measures analysis (nparLD) showed statistically similar results between methods for 9 of 12 distress type-severity combinations (4 types × 3 levels), especially for medium and high severity cases, and that pavement section and method-section factors were significant in 10 and 9 of 12 cases, respectively, indicating spatial variability. Kruskal-Wallis tests were applied to each method separately. Significant section-based differences were found in 11 of 12 cases for the traditional method and in 2 of 12 cases for the in-vehicle image-based method, indicating greater sensitivity of the on-foot inspection to spatial variation in distress distribution. These findings support the statistical validation of the proposed method for practical application in airport pavement management. Furthermore, the comprehensive analysis, which included correlation and autocorrelation studies, revealed a bias in severity level assignment during traditional on-foot inspections. The findings highlight time-efficiency gains with the image-based method and suggest improvements, such as enhancing image quality and providing inspector training to increase the accuracy of severity level classification. These results offer valuable insights for airport pavement managers, contributing to improved safety, operational efficiency, and resilience in the face of growing air traffic demands.
Unidades organizacionais
Descrição
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Financiadores
Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
6817 - DCRRNI ID
Número da atribuição
UIDB/04035/2020