Overgangen bij grasbekledingen in primaire waterkeringen

Dit verslag behandelt de overgangen en potentiele oplossingsrichtingen met betrekking tot overgangen bij grasbekledingen op primaire waterkeringen. Omdat er zeer veel types overgangen mogelijk zijn is er de behoefte om dit te structureren. Een generieke opzet hiertoe is een eerder rapport weergegeven. In voorliggend rapport is dit verder uitgewerkt voor grasbekledingen. De structuur (categorisering) is gebaseerd op het bekledingtype / keringtype, geometrie van de overgang, fysica, locatie op de kering en levensfase van de kering. Huidige kennis van overgangen in grasbekledingen is voornamelijk vastgelegd in ENW/TAW rapporten. Daarnaast is er ervaring met overgangen opgedaan bij proeven met de golfoverslagsimulator (overslag, binnentalud) en de golfklapgenerator (golfklappen op buitentalud) welke in dit rapport zijn samengevat. Op generiek niveau zijn er categorisch verschillende potentiele oplossingsrichtingen geïdentificeerd. Er wordt aanbevolen om: 1 De huidige kennis en ervaring te vertalen in een set met concrete aanbevelingen; 2 Het onderwerp \u91overgangen in primaire waterkeringen\u92 onder de aandacht te brengen van relevante partijen met betrekking tot ontwerp, uitvoering, beheer, toetsing en onderzoek van primaire waterkeringen; 3 Potentiele oplossingsrichtingen met betrekking tot overgangen naar grasbekledingen verder uit te werken

Overgangen en overgangsconstructies

Dit verslag behandelt de kennisleemtes met betrekking tot overgangen in primaire waterkeringen. Omdat er zeer veel types overgangen mogelijk zijn is er de behoefte om dit te structureren. In dit rapport is dit gedaan door verschillende categorieën te definiëren zoals keringtype, geometrie, fysica, locatie op de kering en beheer en inspectie. Er is tevens een inventarisatie van veel voorkomende overgangen gegeven. Gebaseerd op een bijeenkomst van experts in de waterbouwkundige sector en ervaringen uit het buitenland blijken vooral overgangen in grasdijken potentiele zwakke plekken te zijn. In dit verslag wordt tevens een overzicht gegeven van de huidige kennisbasis met betrekking tot overgangen. Recentelijk is er veel onderzoek uitgevoerd naar overgangen in grasbekledingen. Hieruit blijkt dat deze overgangen veelal een potentiele zwakke plek in een waterkering kunnen zijn. Een overzicht van mogelijke oplossingsrichtingen is gegeven voor gras en steenzettingen. Ook deze oplossingsrichtingen zijn gecategoriseerd. Belangrijkste categorieën hierin zijn 1) het verlagen van de belasting, 2) het verhogen van de sterkte en 3) acceptatie dat een overgang een zwakke plek is. Bij de laatste oplossingsrichting wordt de zogenaamde 'reststerkte\u92 aangesproken. Binnen de hierboven genoemde 0plossingsrichtingen zijn nog verschillende sub sets geïdentificeerd. Het wordt aanbevolen om een haalbaarheidsstudie uit te voeren naar het implementeren van de aanbevelingen zoals deze in een Europese studie (FloodProBE) zijn weergegeven in de Nederlandse situatie. In deze studie wordt aanbevolen om overgangen en overgangsconstructies als zodanig herkenbaar te maken in ontwerp-, toets- en beheersstrategieën en rapportages. Op deze manier kan de invloed van een overgang op de stabiliteit van een primaire waterkering in risicomodellen worden geïmplementeerd

SBW project werkelijke sterkte: Projectplan 2009

Het SBW programma heeft als doel onderzoek uit te voeren voor de nieuwe VTV 2011. Het SBW project getiteld werkelijke sterkte beoogt dit te realiseren voor het toetsspoor macrostabiliteit. Dit rapport beschrijft de planning van de werkzaamheden voor 2009 en geeft inzicht in de verwachte werkzaamheden in 2010. Thans is voorzien dat het project in 2010 wordt afgerond.SB

Analyses grass erosion in wave run-up and wave overtopping conditions

Within the framework of WTI, Research and Development of Flood Defence Assessment Tools (Wettelijk Toetsinstrumentarium), which is called in Dutch: WTI-2017 "Onderzoek en ontwikkeling landelijk toetsinstrumentarium", research was carried out to develop an erosion model for grass in the wave run-up zone consistent with the current model in use for the wave overtopping zone. In order to use the erosion model for wave overtopping in the wave run-up zone it was necessary to re-evaluate all wave overtopping tests and to incorporate the flow velocity increase on the slope. This led to a re-evaluation of previously measured critical velocities Uc and cumulative overload D. To validate the erosion model in the wave run-up zone a wave run-up simulator was constructed and tested. The wave run-up generated by the simulator was measured at a test location near the village of Colijnsplaat (Zeeland, The Netherlands). The simulator performed well and four 2 meter wide test strips on the dike were tested with an increasing wave overtopping load. Storm conditions were simulated with a Hmo of 2 m and a (simulated) water level increasing to just below the transition between the hard revetment and the grass revetment. The grass proved to be very erosion resilient and (unfortunately) did not fail. The validation was therefore not optimal, however it the proven strength of the grass has added to the confidence in the model. Apart from the large scale erosion tests small sad pull out tests were performed. The pull-out tests were carried out 'in one go' and fatigue tests were done at ca. 80% of the maximum stress with up to 100 repetitions. The small tests will hopefully link this measurable field parameter to the grass erosion model parameter U, using the turf element model. The objective of WTI-2017 programme is to provide a new set of safety assessment tools for water defences in 2017. This report is product 5.12 of 2014.WT

Golfoverslag en sterkte van binnentaluds van dijken

Het grondgedachte voor het predictiespoor is geschreven volgens het KOLB-principe (www.thesis.nl/kolb). Dit houdt in dat eerst de mogelijke faalmechanismen worden beschreven op basis van bestaande kennis (wat neem je waar? - feeling). Dus een beschrijving van de huidige stand van zaken. Voor zover mogelijk worden dan de faalmechanismen zo goed mogelijk in wiskundige termen beschreven (reflectie op waarnemen \u96watching). Op basis hiervan kan een onderzoek worden opgezet, waarbij nagedacht wordt over de hydraulische belasting en over de te monitoren zaken (begripsvorming - thinking). In de vierde en laatste fase wordt het onderzoek uitgevoerd en geëvalueerd (actief experimenteren, leren \u96 doing). Omdat in ons geval het uitvoeren van de proeven dichtbij het opzetten van de proeven zit, wordt de daadwerkelijke uitvoering daar ondergebracht. Deze derde fase betreft dus het uitvoeren van proeven. De evaluatie is dan de laatste fase. De vier verschillende fasen/onderdelen worden nu verder toegelicht.SB

How To Determine the Phreatic Surface in a Dike during Storm Conditions with Wave Overtopping: A Method Applied to the Afsluitdijk

The most famous dam of the Netherlands, the Afsluitdijk, is in need of renovation. Hydraulic conditions for the year 2050, for some aspects even 2100, must be considered during the renovation of the dam originally constructed 1927-1933. A combination of sea level rise due to climate change and a change in the applied statistical methods result in design conditions that are, at some locations, meters higher than those used a century ago. In a mission to retain the required level of safety while keeping expenses at a minimum, several innovative designs are considered; one of which is to allow very large overtopping discharges by making the dam resilient to erosion. However, calculations have shown that the overtopping values can be over 10 litres per second per meter dam, and the effect of this overtopping on the Afsluitdijk is unknown. In Dutch national design guidelines for dikes, schematizations are proposed for the phreatic surface in dikes during storm conditions. Wave overtopping is mentioned to have a rising effect on the phreatic surface, but clear methods to determine the magnitude of this effect are not prescribed. The guidelines suggest assuming full saturation of the dam in severe overtopping conditions, which has a detrimental effect on the slope stability. Recent studies and large scale infiltration tests on the Afsluitdijk show that only a very limited amount of water infiltrates in the dam and that the assumption of full saturation is much too conservative in case of the Afsluitdijk. In the present study, a finite-element model (Plaxflow) is used to model the phreatic surface in the Afsluitdijk during storm conditions, taking into account the effect of wave overtopping on the phreatic line. Parameters were determined by in-situ and laboratory investigations. To verify the model, calculations were calibrated on standpipe measurements. Wave overtopping is modelled by defining infiltration boundaries based on experiments and sensitivity analyses are conducted. The result of the study is a phreatic surface that can safely be used for the calculation of the slope stability of the levee during predicted storm conditions for the year 2050

Stakeholder values and platform wars: smart meters in the Netherlands

The interconnected nature of the different components of smart grids is a prime example of complexity in technological systems. Developing such systems is highly dependent on the wishes and needs of end-users and other stakeholders. We argue that stakeholder values should be taken into consideration during the design and standardisation of complex infrastructures, and illustrate this with a case of smart meters and home energy management systems. We base our argument on the literature in the technology management fields, particularly those strands related to standardisation. We conduct a case study of the acceptance of smart meters (standards) in the Netherlands, based on stakeholder interviews. We use q-methodology to analyse the most salient values in this case. The Dutch smart meter case arguably demonstrates that a lack of consideration for stakeholder values led to the postponed roll-out of smart meters in the Netherlands. By not addressing privacy issues, economic advantages, and the need for informed consent, the roll-out of smart meters was delayed for several years. This lead to a more gradual approach and increased stakeholder involvement. This case may serve as an example for other European countries who also face public concern regarding the impact of advanced metering infrastructures.Economics of Technology and InnovationValues Technology and InnovationEnergy & Industr

TiEMPO: Open-source time-dependent end-To-end model for simulating ground-based submillimeter astronomical observations

The next technological breakthrough in millimeter–submillimeter astronomy is three-dimensional imaging spectrometry with wide instantaneous spectral bandwidths and wide fields of view. The total optimization of the focal-plane instrument, the telescope, the observing strategy, and the signal-processing software must enable efficient removal of foreground emission from the Earth’s atmosphere, which is time-dependent and highly nonlinear in frequency. Here, we present Time-dependent End-to-end Model for Post-process Optimization (TiEMPO) of the DEep Spectroscopic HIgh-redshift MApper (DESHIMA) spectrometer. TiEMPO utilizes a dynamical model of the atmosphere and parameterized models of the astronomical source, the telescope, the instrument, and the detector. The output of TiEMPO is a time stream of sky brightness temperature and detected power, which can be analyzed by standard signal-processing software. We first compare TiEMPO simulations with an on-sky measurement by the wideband DESHIMA spectrometer, and find good agreement in the noise and sensitivity. We then use TiEMPO to simulate the detection of the line emission spectrum of a high-redshift galaxy using the DESHIMA 2.0 spectrometer in development. The TiEMPO model is open source. Its modular and parametrized design enables users to adapt it to optimize the end-to-end performance of spectroscopic and photometric instruments on existing and future telescopesDreamhalTera-Hertz SensingStatistic

TiEMPO: Open-source time-dependent end-To-end model for simulating ground-based submillimeter astronomical observations

The next technological breakthrough in millimeter-submillimeter astronomy is 3D imaging spectrometry with wide instantaneous spectral bandwidths and wide fields of view. The total optimization of the focal-plane instrument, the telescope, the observing strategy, and the signal-processing software must enable efficient removal of foreground emission from the Earth's atmosphere, which is time-dependent and highly nonlinear in frequency. Here we present TiEMPO: Time-dependent End-To-end Model for Post-process Optimization of the DESHIMA spectrometer. TiEMPO utilizes a dynamical model of the atmosphere and parametrized models of the astronomical source, the telescope, the instrument, and the detector. The output of TiEMPO is a timestream of sky brightness temperature and detected power, which can be analyzed by standard signal-processing software. We first compare TiEMPO simulations with an on-sky measurement by the wideband DESHIMA spectrometer, and find good agreement in the noise power spectral density and sensitivity. We then use TiEMPO to simulate the detection of the line emission spectrum of a high-redshift galaxy using the DESHIMA 2.0 spectrometer in development. The TiEMPO model is open source. Its modular and parametrized design enables users to adapt it to design and optimize the end-To-end performance of spectroscopic and photometric instruments on existing and future telescopes. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Tera-Hertz SensingStatistic

Micro-Targeting and ICT media in the Dutch Parliamentary system: Technological changes in Dutch Democracy

For the period surrounding the 2018 Dutch municipal elections, a team of researchers from the Delft University of Technology investigated the effect of the digital environment on parliamentary democracy. An interdisciplinary group of researchers combined expertise on digital ethics, political theory, big data analytics, the economics of privacy and security, epistemology, media studies and computer science. This report presents the main findings, which are grouped around two main themes: political micro-targeting and ICT media. Societal themes that came to prominence over the research period, such as the debate over ‘fake news’ and the leaks of personal information that were used for political purposes by Facebook, as well as the implementation of new EU privacy regulation helped to put the research in a larger political context. The main findings provide a qualified picture. The influence of the digital revolution on democratic politics is already revolutionary, and the weaknesses of online platforms provide ample opportunities for derailing liberal democracy. Digital platforms are too closed-off, not mindful enough of individual digital rights, and biased in their (re)presentation of political pluralism. But the Netherlands has proven to be one of the few democracies that is relatively resilient, with an open multi-party system receptive to the political fragmentation that ICT developments encourage, and relatively high trust between citizens, in shared media organizations, and between political parties. In order not to be complacent in the face of fundamental challenges, the report provides several urgent recommendations. Next to several ‘reactive’ recommendations, which seek to remedy the weaknesses and dangers the digital environment poses to democracy, it also outlines an example of how the digital environment might be proactively redesigned in order to positively enhance the quality of the Dutch parliamentary system.Ethics & Philosophy of TechnologyValues Technology and InnovationPolicy AnalysisOrganisation and Governanc