A multidimensional analytical approach for identifying and locating large utility pipes in underground infrastructure

The population growth, technological improvements, and the need for repairing old or installing new utilities result in a high demand for trenching and drilling activities. However, penetrating the subsurface incurs the risk of damaging existing underground facilities because they were not properly documented, if at all. Ground Penetrating Radar (GPR) constitutes a well-established technology that uses electromagnetic waves to identify objects underground by detecting their reflections. The work presented in this paper focuses on the timing and other characteristics of radar pulses reflected from the buried utilities. It is hypothesised that integrating the knowledge of construction practice, geophysical principles, and electromagnetic wave propagation behaviour in various soil conditions will improve the reliability and accuracy of GPR. This paper presents the results of field experiments that studied the effects of large void such as sinkholes or drainage pipes in several undergrounds. It provides important insights into the features and patterns that can be used to improve current methods

The Primacy of As-Built Drawings in the Management of Underground Utility Operations: A New Zealand Study

Publishe

A new WebGIS approach to support ground penetrating radar deployment

En raison de l’agglomération complexe des infrastructures souterraines dans les grandes zones urbaines et des préoccupations accrues des municipalités ou des gouvernements qui déploient des systèmes d’information foncière ou des industries qui souhaitent construire ou creuser, il devient de plus en plus impératif de localiser et de cartographier avec précision les pipelines, les câbles d’énergie hydroélectrique, les réseaux de communication ou les conduites d’eau potable et d’égout. Le géoradar (Ground Penetrating Radar ou GPR) est un outil en géophysique qui permet de produire des images en coupe du sous-sol desquelles de l’information utile sur les infrastructures souterraines peut être tirée. Des expériences antérieures et une analyse documentaire approfondie ont révélé que les logiciels disponibles pour réaliser des levés GPR qui sont utilisés directement sur le terrain et hors site ne reposent pas ou très peu sur des fonctionnalités géospatiales. En outre, l’intégration de données telles que la visualisation de données GPR dans des espaces géoréférencés avec des orthophotos, des cartes, des points d’intérêt, des plans CAO, etc., est impossible. Lorsque disponible, l’ajout d’annotations ou l’interrogation d’objets géospatiaux susceptibles d’améliorer ou d’accélérer les investigations ne proposent pas des interfaces conviviales. Dans ce projet de recherche, une nouvelle approche est proposée pour déployer le GPR et elle est basée sur quatre fonctionnalités issues du Web et des systèmes d’information géographique (WebGIS) jugées essentielles pour faciliter la réalisation de levés GPR sur le terrain. Pour démontrer la faisabilité de cette nouvelle approche, une extension de la plate-forme logicielle existante GVX (conçue et vendue par Geovoxel) appelée GVX-GPR a été développée. GVX-GPR propose aux utilisateurs d’instruments GPR quatre fonctionnalités soit 1) intégration de cartes, 2) géo-annotations et points d’intérêt, 3) géoréférencement et visualisation de radargrammes et 4) visualisation de sections GPR géoréférencées. Afin de tester l’approche WebGIS et GPXGPR, deux sites d’étude ont été relevés par deux professionnels différents, un expert et un non-expert en géophysique, ont été sélectionnés. Une première expérimentation réalisée sur le campus de l’Université Laval à Québec prévoyait l’identification de trois objets enterrés soit un câble électrique, une fibre optique et un tunnel dont leur position XYZ était connue. Le deuxième essai s’est passé à l’Universidade Federal do Rio de Janeiro (Rio de Janeiro, Brésil), avec un professionnel expert en géophysique. Ce 2e site cherchait à reproduire un environnent plus réaliste avec une quantité inconnue d’objets enterrés. Les quatre fonctionnalités proposées par GVX-GPR ont donc été testées et leur intérêt discuté par les deux utilisateurs GPR. Les deux utilisateurs GPR se sont dits très intéressés par l’outil GVX-GPR et ses nouvelles fonctionnalités et ils aimeraient pouvoir l’intégrer à leur travail quotidien car ils y voient des avantages. En particulier, l’approche et GVX-GPR les a aidés à découvrir de nouvelles cibles, à délimiter le territoire à couvrir, à interpréter les données GPR brutes en permettant l’interaction entre les données géospatiales (en ligne) et les profils de données GPR, et finalement pour la cartographie à produire tout en respectant la norme CityGML (donc utile au partage éventuel des données). De même, une fois le système maitrisé, GVX-GPR a permis d’optimiser la durée du levé. Ce projet de maitrise a donc permis d’élaborer une nouvelle approche pour effectuer des levés GPR et proposer un outil logiciel pour tester la faisabilité de celle-ci. Une première étape de validation de la faisabilité et de l’utilité a été réalisée grâce aux deux tests effectués. Évidemment, ces deux tests sont des premiers pas dans une phase plus large de validation qui pourrait s’effectuer, et ils ont ouvert la porte à des ajustements ou l’ajout d’autres fonctionnalités, comme la manipulation des outils de visualisation 3D et l’ajout de filtres et traitement de signal. Nous estimons néanmoins ces premiers tests concluant pour ce projet de maîtrise, et surtout ils démontrent que les instruments GPR gagneraient à davantage intégrer les données et fonctionnalités géospatiales. Nous pensons également que nos travaux vont permettre à des communautés de non spécialistes en géophysique de s’intéresser aux instruments de type GPR pour les levés d’objets enfouis. Notre approche pourra les aider à préparer les données géospatiales utiles à la planification, à effectuer le levé terrain et à produire les cartes associéesDue to the complex agglomeration of underground infrastructures in large urban areas and accordingly increased concerns by municipalities or government who deploy land information systems or industries who want to construct or excavate, it is imperative to accurately locate and suitability map existing underground utility networks (UUN) such as pipelines, hydroelectric power cables, communication networks, or drinking water and sewage conduits. One emerging category of instrument in geophysics for collecting and extracting data from the underground is the ground penetrating radar (GPR). Previous experiments and a thorough literature review revealed that GPR software used in and off the field do not take advantage of geospatial features and data integration such as visualization of GPR data in a georeferenced space with orthophotographies, map, point of interest, CAD plans, etc. Also missing is the capability to add annotation or querying geospatial objects that may improve or expedite the investigations. These functions are long-lived in the geospatial domain, such as in geographic information system (GIS). In this research project, a new approach is proposed to deploy GPR based on four core WebGIS-enabled features, used to support field investigations with GPR. This WebGIS is based on an existing platform called GVX, designed and sold by Geovoxel as a risk management tool for civil engineering projects. In this proposed approach, a generic guideline based on GVX-GPR was developed which users can follow when deploying GPR. This approach is based on four core features which are missing on most GPR software, (1) map integration, (2) geo-annotations and points of interest, (3) radargram georeferencing and visualization, and (4) georeferenced slice visualization. In order to test the designed WebGIS-based approach, two different professionals, an expert in geophysics and a person without any background in geophysics, used the proposed approach in their day-to-day professional practice. The first experiment was conducted at Université Laval (Québec – Canada) when the subject undertook an area to a survey in order to identify 3 possible targets premapped. The second, with a Geophysics-specialist, took place in Rio de Janeiro, at Universidade Federal do Rio de Janeiro’s campus. This study covered an area counting on an unknown number of buried objects, aiming at reproducing a realistic survey scenario. Four new feature were added and discussed with GPR practitioners. Both GPR user declared to be very interested by the proposed by the tool GVX-GPR and its features, being willing to apply this software on their daily basis due to the added advantages. Particularly, this approach has aided these professionals to find new buried objects, delimit the survey area, interpret raw GPR data by allowing geospatial data interaction and GPR profiles, and, finally, to produce new maps compliant with standards such as CityGML. Also, once mastered, the technology allowed the optimization of survey time. This project enabled the development of a new approach to leverage GPR surveys and proposed a new tool in order to test the approach’s feasibility. A first step into the validation of this proposal has been taken towards a feasibility and utility evaluation with two tests accomplished. Unmistakably, these are the first steps of a likely larger validation process, opening up new possibilities for the continuity of the project such as the addition of signal processing techniques and 3D data handling. We nevertheless consider these conclusive for this master’s project, above all demonstrating the value add by geospatial data integration and functions to GPR instruments. This work is also intended to the community of newcomers, or interested in GPR, to further explore this technology, since this approach shall facilitate the preparation, execution, and post-processing phases of a GPR survey

Characterization of components of water supply systems from GPR images and tools of intelligent data analysis

[EN] Over time, due to multiple operational and maintenance activities, the networks of water supply systems (WSSs) undergo interventions, modifications or even are closed. In many cases, these activities are not properly registered. Knowledge of the paths and characteristics (status and age, etc.) of the WSS pipes is obviously necessary for efficient and dynamic management of such systems. This problem is greatly augmented by considering the detection and control of leaks. Access to reliable leakage information is a complex task. In many cases, leaks are detected when the damage is already considerable, which brings high social and economic costs. In this sense, non-destructive methods (e.g., ground penetrating radar - GPR) may be a constructive response to these problems, since they allow, as evidenced in this thesis, to ascertain paths of pipes, identify component characteristics, and detect primordial water leaks. Selection of GPR in this work is justified by its characteristics as non-destructive technique that allows studying both metallic and non-metallic objects. Although the capture of information with GPR is usually successful, such aspects as the capture settings, the large volume of generated information, and the use and interpretation of such information require high level of skill and experience. This dissertation may be seen as a step forward towards the development of tools able to tackle the problem of lack of knowledge on the WSS buried assets. The main objective of this doctoral work is thus to generate tools and assess their feasibility of application to the characterization of components of WSSs from GPR images. In this work we have carried out laboratory tests specifically designed to propose, develop and evaluate methods for the characterization of the WSS buried components. Additionally, we have conducted field tests, which have enabled us to determine the feasibility of implementing such methodologies under uncontrolled conditions. The methodologies developed are based on techniques of intelligent data analysis. The basic principle of this work has involved the processing of data obtained through the GPR to look for useful information about WSS components, with special emphasis on the pipes. After performing numerous activities, one can conclude that, using GPR images, it is feasible to obtain more information than the typical identification of hyperbolae currently performed. In addition, this information can be observed directly, e.g. more simply, using the methodologies proposed in this doctoral work. These methodologies also prove that it is feasible to identify patterns (especially with the preprocessing algorithm termed Agent race) that provide fairly good approximation of the location of leaks in WSSs. Also, in the case of pipes, one can obtain such other characteristics as diameter and material. The main outcomes of this thesis consist in a series of tools we have developed to locate, identify and visualize WSS components from GPR images. Most interestingly, the data are synthesized and reduced so that the characteristics of the different components of the images recorded in GPR are preserved. The ultimate goal is that the developed tools facilitate decision-making in the technical management of WSSs, and that such tools can even be operated by personnel with limited experience in handling non-destructive methodologies, specifically GPR.[ES] Con el paso del tiempo, y debido a múltiples actividades operacionales y de mantenimiento, las redes de los sistemas de abastecimiento de agua (SAAs) sufren intervenciones, modificaciones o incluso, son clausuradas, sin que, en muchos casos, estas actividades sean correctamente registradas. El conocimiento de los trazados y características (estado y edad, entre otros) de las tuberías en los SAAs es obviamente necesario para una gestión eficiente y dinámica de tales sistemas. A esta problemática se suma la detección y el control de las fugas de agua. El acceso a información fiable sobre las fugas es una tarea compleja. En muchos casos, las fugas son detectadas cuando los daños en la red son ya considerables, lo que trae consigo altos costes sociales y económicos. En este sentido, los métodos no destructivos (por ejemplo, ground penetrating radar - GPR), pueden ser una respuesta a estas problemáticas, ya que permiten, como se pone de manifiesto en esta tesis, localizar los trazados de las tuberías, identificar características de los componentes y detectar las fugas de agua cuando aún no son significativas. La selección del GPR, en este trabajo se justifica por sus características como técnica no destructiva, que permite estudiar tanto objetos metálicos como no metálicos. Aunque la captura de información con GPR suele ser exitosa, la configuración de la captura, el gran volumen de información, y el uso y la interpretación de la información requieren de alto nivel de habilidad y experiencia por parte del personal. Esta tesis doctoral se plantea como un avance hacia el desarrollo de herramientas que permitan responder a la problemática del desconocimiento de los activos enterrados de los SAAs. El objetivo principal de este trabajo doctoral es, pues, generar herramientas y evaluar la viabilidad de su aplicación en la caracterización de componentes de un SAA, a partir de imágenes GPR. En este trabajo hemos realizado ensayos de laboratorio específicamente diseñados para plantear, elaborar y evaluar metodologías para la caracterización de los componentes enterrados de los SAAs. Adicionalmente, hemos realizado ensayos de campo, que han permitido determinar la viabilidad de aplicación de tales metodologías bajo condiciones no controladas. Las metodologías elaboradas están basadas en técnicas de análisis inteligentes de datos. El principio básico de este trabajo ha consistido en el tratamiento adecuado de los datos obtenidos mediante el GPR, a fin de buscar información de utilidad para los SAAs respecto a sus componentes, con especial énfasis en las tuberías. Tras la realización de múltiples actividades, se puede concluir que es viable obtener más información de las imágenes de GPR que la que actualmente se obtiene con la típica identificación de hipérbolas. Esta información, además, puede ser observada directamente, de manera más sencilla, mediante las metodologías planteadas en este trabajo doctoral. Con estas metodologías se ha probado que también es viable la identificación de patrones (especialmente el pre-procesado con el algoritmo Agent race) que proporcionan aproximación bastante acertada de la localización de las fugas de agua en los SAAs. También, en el caso de las tuberías, se puede obtener otro tipo de características tales como el diámetro y el material. Como resultado de esta tesis se han desarrollado una serie de herramientas que permiten visualizar, identificar y localizar componentes de los SAAs a partir de imágenes de GPR. El resultado más interesante es que los resultados obtenidos son sintetizados y reducidos de manera que preservan las características de los diferentes componentes registrados en las imágenes de GPR. El objetivo último es que las herramientas desarrolladas faciliten la toma de decisiones en la gestión técnica de los SAAs y que tales herramientas puedan ser operadas incluso por personal con una experiencia limitada en el manejo[CA] Amb el temps, a causa de les múltiples activitats d'operació i manteniment, les xarxes de sistemes d'abastament d'aigua (SAAs) se sotmeten a intervencions, modificacions o fins i tot estan tancades. En molts casos, aquestes activitats no estan degudament registrats. El coneixement dels camins i característiques (estat i edat, etc.) de les canonades d'aigua i sanejament fa evident la necessitat d'una gestió eficient i dinàmica d'aquests sistemes. Aquest problema es veu augmentat en gran mesura tenint en compte la detecció i control de fuites. L'accés a informació fiable sobre les fuites és una tasca complexa. En molts casos, les fugues es detecten quan el dany ja és considerable, el que porta costos socials i econòmics. En aquest sentit, els mètodes no destructius (per exemple, ground penetrating radar - GPR) poden ser una resposta constructiva a aquests problemes, ja que permeten, com s'evidencia en aquesta tesi, per determinar rutes de canonades, identificar les característiques dels components, i detectar les fuites d'aigua quan encara no són significatives. La selecció del GPR en aquest treball es justifica per les seves característiques com a tècnica no destructiva que permet estudiar tant objectes metàl·lics i no metàl·lics. Tot i que la captura d'informació amb GPR sol ser reeixida, aspectes com ara la configuració de captura, el gran volum d'informació que es genera, i l'ús i la interpretació d'aquesta informació requereix alt nivell d'habilitat i experiència. Aquesta tesi pot ser vista com un pas endavant cap al desenvolupament d'eines capaces d'abordar el problema de la manca de coneixement sobre els actius d'aigua i sanejament enterrat. L'objectiu principal d'aquest treball doctoral és, doncs, generar eines i avaluar la seva factibilitat d'aplicació a la caracterització dels components de los SAAs, a partir d'imatges GPR. En aquest treball s'han dut a terme proves de laboratori específicament dissenyats per proposar, desenvolupar i avaluar mètodes per a la caracterització dels components d'aigua i sanejament soterrat. A més, hem dut a terme proves de camp, que ens han permès determinar la viabilitat de la implementació d'aquestes metodologies en condicions no controlades. Les metodologies desenvolupades es basen en tècniques d'anàlisi intel·ligent de dades. El principi bàsic d'aquest treball ha consistit en el tractament de dades obtingudes a través del GPR per buscar informació útil sobre els components d'SAA, amb especial èmfasi en la canonades. Després de realitzar nombroses activitats, es pot concloure que, amb l'ús d'imatges de GPR, és factible obtenir més informació que la identificació típica d'hipèrboles realitzat actualment. A més, aquesta informació pot ser observada directament, per exemple, més simplement, utilitzant les metodologies proposades en aquest treball doctoral. Aquestes metodologies també demostren que és factible per identificar patrons (especialment el pre-processat amb l'algoritme Agent race) que proporcionen bastant bona aproximació de la localització de fuites en SAAs. També, en el cas de tubs, es pot obtenir altres característiques com ara el diàmetre i el material. Els principals resultats d'aquesta tesi consisteixen en una sèrie d'eines que hem desenvolupat per localitzar, identificar i visualitzar els components dels SAAS a partir d'imatges GPR. El resultat més interessant és que els resultats obtinguts són sintetitzats i reduïts de manera que preserven les característiques dels diferents components registrats en les imatges de GPR. L'objectiu final és que les eines desenvolupades faciliten la presa de decisions en la gestió tècnica de SAA, i que tals eines poden fins i tot ser operades per personal amb poca experiència en el maneig de metodologies no destructives, específicament GPR.Ayala Cabrera, D. (2015). Characterization of components of water supply systems from GPR images and tools of intelligent data analysis [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59235TESISPremios Extraordinarios de tesis doctorale

Network Interdependency Modeling for Risk Assessment on Built Infrastructure Systems

As modern infrastructures become more interconnected, the decision-making process becomes more difficult because of the increased complexity resulting from infrastructure interdependencies. Simulation and network modeling provide a way to understand system behavior as a result of interdependencies. One area within the asset management literature that is not well covered is infrastructure system decay and risks associated with that decay. This research presents an enhanced version of Haimes\u27 input-output inoperability model (IIM) in the analysis of built infrastructure systems. Previous applications of the IIM characterized infrastructure at the national level utilizing large economic databases. This study develops a three-phased approach that takes component level data stored within geographic information systems (GIS) to provide a metric for network interdependency across a municipal level infrastructure. A multi-layered approach is proposed which leverages the layered data structure of GIS. Furthermore, Monte Carlo simulation using stochastic decay estimates shows how infrastructure risk as a result of interdependency effects changes over time. Such an analysis provides insight to infrastructure asset managers on the impact of policy and strategy decision-making regarding the maintenance and management of their infrastructure systems

The Dialectics of Urban Water Poverty Trajectories: Policy-driven and Everyday Practices in Dar es Salaam

The Joint Monitoring Programme estimates that urban Sub-Saharan Africa experiences the highest levels of water poverty, i.e. much of the housing lacks access to basic drinking water and sanitation services (WSS). While the actual number of people that gained access in urban areas since 1990 may have increased, in Tanzania the percentage of people with improved access to water has declined. Dar es Salaam, a city facing growing challenges with the equitable provision of water services, is no exception. Failure of policy-driven practices (those by government, private sector providers, external support agencies and other key players in infrastructure development) to adequately address urban water poverty, has increased the reliance of poor women and men on a range of everyday practices to meet their WSS needs, including community-managed systems and informal private providers. This thesis examines how ‘the urban water poor’ move in and out of urban water poverty and how they do so in different ways, exploring the interrelations between policy-driven and everyday practices and their influence on individual trajectories. The research adopts a normative perspective based on principles of socioenvironmental justice that include distribution, recognition and parity of participation, and applies a relational approach that draws on intersectionality scholarship and emphasises intersections of time, space and socioenvironmental relations. Findings confirm a dialectic relationship between policy-driven and everyday practices with multiple examples where conditions under which urban water poverty prevails are produced, reproduced and normalised. However, evidence further shows instances of more transformative practices that challenge unjust processes and outcomes with a potential for people to move out of it. Research findings highlight how spatial and temporal specificity alongside people’s intersectional identities and relations, shape individual trajectories and define who can and cannot escape water poverty traps and why. This thesis argues that a relational investigation of urban water poverty trajectories can help tackle the problem by identifying which factors pull people out of urban water poverty and which ones push them deeper into it