This thesis addresses numerical simulations of self-compacting concrete (SCC) castings and suggests a novel modelling approach that treats reinforcement zones in a formwork as porous media. As a relatively new field in concrete technology, numerical simulations of fresh concrete flow can be a promising aid to optimise casting processes and to avoid on-site casting incidents by predicting the flow behaviour of concrete during the casting process. The simulations of fresh concrete flow generally involve complex mathematical modelling and time-consuming computations. In case of a casting prediction, the simulation time is additionally significantly increased because each reinforcement bar occurring in succession has to be considered one by one. This is particularly problematic when simulating SCC casting, since this type of concrete is typically used for heavily reinforced structural members. However, the wide use of numerical tools for casting prediction in practice is possible only if the tools are user-friendly and simulations are time-saving. In order to shorten simulation time and to come closer to a practical tool for casting prediction, instead to model steel bars one by one, this thesis suggests to model zones with arrays of steel bars as porous media. Consequently, one models the flow of SCC through a reinforcement zone as a free-surface flow of a non-Newtonian fluid, propagating through the medium. By defining characteristic parameters of the porous medium, the influence on the flow and the changed (apparent) behaviour of concrete in the porous matrix can be predicted. This enables modelling of any reinforcement network as a porous zone and thus significantly simplifies and fastens simulations of reinforced components’ castings. Within the thesis, a computational model for SCC flow through reinforced sections was developed. This model couples a fluid dynamics model for fresh concrete and the macroscopic approach for the influence of the porous medium (formed by the rebars) on the flow. The model is implemented into a Computational Fluid Dynamics software and validated on numerical and experimental studies, among which is a large-scale laboratory casting of a highly reinforced beam. The apparent rheology of concrete within the arrays of steel bars is studied and a methodology to determine unknown input parameters for the porous medium is suggested. Normative tables defining characteristic porous medium parameters as a function of the topology of the rebar zone for different reinforcement cases are generated. Finally, the major contribution of this work is the resulting numerical package, consisting of the numerical solver and the parameter library. The thesis concludes on the ability of the porous medium analogy technique to reliably predict the concrete casting behaviour, while being significantly easier to use and far less time consuming than existing tools. / Die Arbeit behandelt die numerische Modellierung des Fließverhaltens von selbst-verdichtendem Beton (SVB) in bewehrten Schalungselementen. Die numerische Simulation des Fließens von Frischbeton kann eine vielversprechende Unterstützung bei der Optimierung von Befüllvorgängen sein, indem diese bereits im Vorfeld vorhergesagt werden. Die Simulation des Fließens von Frischbeton verwendet komplizierte mathematische Modelle und zeitintensive Rechenoperationen. Darüber hinaus wird die Simulationszeit für die Vorhersage des Füllvorgangs zusätzlich deutlich verlängert, weil aufeinanderfolgende Bewehrungsstäbe einzeln zu berücksichtigen sind. Das ist insbesondere für die Simulation von SVB ein entscheidendes Problemfeld, da SVB oft gerade für hochbewehrte Bauteile verwendet wird. Dennoch ist ein weitreichender Einsatz von numerischen Hilfsmitteln bei der Vorhersage von Füllprozessen nur denkbar, wenn die Anwenderfreundlichkeit und eine Zeitersparnis gewährleistet werden können. Um die Simulationszeit zu verkürzen und näher an eine anwenderfreundliche Lösung für die Vorhersage von Füllprozessen zu kommen, wird als Alternative zur einzelnen Modellierung aller Stahlstäbe in dieser Arbeit vorgeschlagen, Zonen mit Bewehrungsstäben als poröse Medien zu modellieren. Infolgedessen wird das Fließen von SVB durch bewehrte Zonen als Strömung eines nicht-Newton’schen Fluides durch ein poröses Medium betrachtet. Durch die Definition charakteristischer Parameter des porösen Mediums kann das veränderte Verhalten des Betons in der porösen Matrix vorhegesagt werden. Dies ermöglicht die Modellierung beliebiger Bewehrungszonen und vereinfacht und beschleunigt folglich die numerische Simulation bewehrter Bauteile. Im Rahmen der Arbeit wird ein Rechenmodell für das Fließverhalten von SVB durch bewehrte Schalungszonen entwickelt. Das Modell verkoppelt das Strömungsverhalten von Beton mit dem makroskopischen Ansatz für den Einfluss von porösen Medien, welche in diesem Fall die Bewehrungsstäbe ersetzen. Das entwickelte Modell wird in eine CFD-Software implementiert und anhand mehrerer numerischer und experimenteller Studien validiert, darunter auch ein maßstabsgetreues Fließexperiment eines hochbewehrten Balkens. Darüber hinaus wird die scheinbare Rheologie des Betons innerhalb der Anordnung der Stahlstäbe untersucht und daraus eine Methode zur Bestimmung unbekannter Parameter für das poröse Medium vorgeschlagen. Es werden hierfür auch normative Tabellen generiert, die die charakteristischen Eigenschaften der porösen Medien für unterschiedliche Bewehrungsanordnungen abbilden. Zuletzt ist der Hauptbeitrag dieser Arbeit das resultierende Numerikpaket, bestehend aus dem numerischen Solver einschließlich des implementierten Modells sowie der Parameterbibliothek. Im Abschluss werden die Verlässlichkeit der Vorhersage von Füllvorgängen durch die Analogie zu porösen Medien erörtert sowie Schlussfolgerungen zur deutlichen Ersparnis an Aufwand und Zeit gegenüber herkömmlichen Methoden vorgenommen.

The irrigated agriculture in the Lower Chenab Canal (LCC) of Pakistan is characterized by huge water utilization both from surface and groundwater resources. Need of utilization of water from five rivers in Punjab province along with accelerated population growth has forced the construction of world’s largest irrigation network. Nevertheless, huge irrigation infrastructure, together with inappropriate drainage infrastructure, led to a build-up of shal-low groundwater levels, followed by waterlogging and secondary salinization in the soil profile. Following this era, decreased efficiency of irrigation supply system along with higher food demands had increased burdens on groundwater use, which led to a drop in groundwater levels in major parts of LCC. Previous studies in the study region revealed lacking management and maintenance of irrigation system, inflexible irrigation strategies, poor linkages between field level water supply and demands. No future strategy is present or under consideration to deal with this long time emerged groundwater situation particularly under unchanged irrigation water supply and climate change. Therefore, there is an utmost importance to assess the current profile of water use in the irrigation scheme and to device some workable strategies under future situations of land use and climate change. This study aims to investigate the spatio-temporal status of water utilization and performance of irrigation system using remote sensing data and techniques (SEBAL) in combination with other point data. Different irrigation performance indicators including equity, adequacy and reliability using evaporation fraction as main input parameter are utilized. Current profiles of land use/land cover (LULC) areas are assessed and their change detections are worked out to establish realistic future scenarios. Spatially distributed seasonal net recharge, a very important input parameter for groundwater modeling, is estimated by employing water balance approaches using spatial data from remote sensing and local norms. Such recharge results are also compared with a water table fluctuation approach. Following recharge estimation, a regional 3-D groundwater flow model using FEFLOW was set up. This model was calibrated by different approaches ranging from manual to automated pilot point (PP) approach. Sensitivity analysis was performed to see the model response against different model input parameters and to identify model regions which demand further improvements. Future climate parameters were downscaled to establish scenarios by using statistical downscaling under IPCC future emission scenarios. Modified recharge raster maps were prepared under both LULC and climate change scenarios and were fed to the groundwater model to investigate groundwater dynamics. Seasonal consumptive water use analysis revealed almost double use for kharif as compared to rabi cropping seasons with decrease from upper LCC to lower regions. Intra irrigation subdivision analysis of equity, an important irrigation performance indicator, shows less differences in water consumption in LCC. However, the other indicators (adequacy and reliability) indicate that the irrigation system is neither adequate nor reliable. Adequacy is found more pronounced during kharif as compared to rabi seasons with aver-age evaporation fraction of 0.60 and 0.67, respectively. Similarly, reliability is relatively higher in upper LCC regions as compared to lower regions. LULC classification shows that wheat and rice are major crops with least volatility in cultivation from season to season. The results of change detection show that cotton exhibited maximum positive change while kharif fodder showed maximum negative change during 2005-2012. Transformation of cotton area to rice cultivation is less conspicuous. The water consumption in upper LCC regions with similar crops is relatively higher as compared to lower regions. Groundwater recharge results revealed that, during the kharif cropping seasons, rainfall is the main source of recharge followed by field percolation losses, while for rabi cropping seasons, canal seepage remains the major source. Seasonal net groundwater recharge is mainly positive during all kharif seasons with a gradual increase in groundwater level in major parts of LCC. Model optimization indicates that PP is more flexible and robust as compared to manual and zone based approaches. Different statistical indicators show that this method yields reliable calibration and validation as values of Nash Sutcliffe Efficiency are 0.976 and 0.969, % BIAS are 0.026 and -0.205 and root mean square errors are 1.23 m and 1.31 m, respectively. Results of model output sensitivity suggest that hydraulic conductivity is a more influential parameter in the study area than drain/fillable porosity. Model simulation results under different scenarios show that rice cultivation has the highest impact on groundwater levels in upper LCC regions whereas major negative changes are observed for lower parts under decreased kharif fodder area in place of rice, cotton and sugarcane. Fluctuations in groundwater level among different proposed LULC scenarios are within ±1 m, thus showing a limited potential for groundwater management. For future climate scenarios, a rise in groundwater level is observed for 2011 to 2025 under H3A2 emission regime. Nevertheless, a drop in groundwater level is expected due to increased crop consumptive water use and decreased precipitations under H3A2 scenario for the periods 2026-2035 and 2036-2045. Although no imminent threat of groundwater shortage is anticipated, there is an opportunity for developing groundwater resources in the lower model regions through water re-allocation that would be helpful in dealing water shortages. The groundwater situation under H3B2 emission regime is relatively complex due to very low expectation of rise in groundwater level through precipitation during 2011-2025. Any positive change in groundwater under such scenarios is mainly associated with changes in crop consumptive water uses. Consequently, water management under such situation requires revisiting of current cropping patterns as well as augmenting water supply through additional surface water resources.:ABSTRACT VIII ZUSAMMENFASSUNG X ACRONYMS 1 Chapter 1 3 GENERAL INTRODUCTION 3 1 Groundwater for irrigated agriculture 3 2 Groundwater development in Pakistan 4 3 Study area 6 4 History of groundwater use in the study area 7 5 Research agenda 8 5.1 Problem statement 8 5.2 Objectives and scope of the study 9 Chapter 2 12 OVERVIEW OF PUBLICATIONS 12 Chapter 3 16 GENERAL CONCLUSIONS AND POLICY RECOMMENDATIONS 16 REFERENCES 20 ANNEXES 23 ACKNOWLEDGEMENTS 123

Clay formations are investigated worldwide as potential host rock for the deep geological disposal of high-level radioactive waste (HLW). Usually bentonite is preferred as the buffer and backfill material in the disposal system. In the disposal of HLW, heat emission is one of the most important issues as it can generate a series of complex thermo-hydro-mechanical (THM) processes in the surrounding materials and thus change the material properties. In the context of safety assessment, it is important to understand the thermally induced THM interactions and the associated change in material properties. In this work, the thermally induced coupled THM behaviours in the clay host rock and in the bentonite buffer as well as the corresponding coupling effects among the relevant material properties are numerically analysed. A coupled non-isothermal Richards flow mechanical model and a non-isothermal multiphase flow model were developed based on the scientific computer codes OpenGeoSys (OGS). Heat transfer in the porous media is governed by thermal conduction and advective flow of the pore fluids. Within the hydraulic processes, evaporation, vapour diffusion, and the unsaturated flow field are considered. Darcy’s law is used to describe the advective flux of gas and liquid phases. The relative permeability of each phase is considered. The elastic deformation process is modelled by the generalized Hooke’s law complemented with additional strain caused by swelling/shrinkage behaviour and by temperature change. In this study, special attention has been paid to the analysis of the thermally induced changes in material properties. The strong mechanical and hydraulic anisotropic properties of clay rock are described by a transversely isotropic mechanical model and by a transversely isotropic permeability tensor, respectively. The thermal anisotropy is described by adoption of the bedding-orientation-dependent thermal conductivity. The dependency of the thermal conductivity on the degree of water saturation, the dependency of the thermal effects on the water retention behaviour, and the dependency of the effects of the pore pressure variation on the permeability and the anisotropic swelling/shrinkage behaviour have been intensively analysed and the corresponding numerical models to consider those coupling effects have been developed. The developed numerical model has been applied to simulate the laboratory and in situ heating experiments on the bentonite and clay rock at different scales. Firstly the laboratory heating experiment on Callovo-Oxfordian Clay (COX) and the laboratory long-term heating and hydration experiment on MX80 pellets were simulated. Based on the knowledge from the numerical analysis of the laboratory experiments, a 1:2 scale in situ heating experiment of an integrated system of the bentonite engineered barrier system (EBS) in the Opalinus Clay host rock was simulated. All the relevant operation phases were considered in the modelling. Besides, the modelling was extended to 50 years after the heat shut-down with the aim of predicting the long-term behaviours. Additionally, variation calculations were carried out to investigate the effects of the storage capacity of the Opalinus Clay on the thermally induced hydraulic response. In the long-term modelling, the effects of different saturated water permeabilities of buffer material on the resaturation process were analysed. Based on the current researches and model developments, the observed THM behaviours of the bentonite buffer and the clay rock, that is, the measured evolution of temperature, pore pressure, humidity, swelling pressure, and so on in the laboratory and in situ experiments can be reproduced and interpreted well. It is proved that by using both a non-isothermal multiphase flow model and a non-isothermal Richards flow model combined with the corresponding thermal and mechanical models, the major THM behaviours can be captured. It is validated that the developed model is able to simulate the relevant coupled THM behaviours of clayey material under the well-defined laboratory conditions as well as under the complex natural disposal conditions.

Liquefaction is the phenomena when there is loss of strength in saturated and cohesion-less soils because of increased pore water pressures and hence reduced effective stresses due to dynamic loading. It is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading. In this study, after the short review of liquefaction definition, the models of prediction and estimation of liquefaction were considered. Application of numerical modelling with two major software (FLAC & PLAXIS) for the Wildlife site liquefaction, under superstition earthquake in 1987 were compared and analysed. Third step was started with introduction of Fuzzy logic and neural network as two common intelligent mathematical methods. These two patterns for prediction of soil liquefaction were combined. The “Neural network- Fuzzy logic-Liquefaction- Prediction” (NFLP) was applied for liquefaction prediction in Wildlife site. The results show the powerful prediction of liquefaction happening with high degree of accuracy in this case.

This thesis presents a new stratigraphic forward numerical model to simulate the carbonate production of marine sedimentary basin through ecological model which is implemented in the SIMSAFADIM-CLASTIC program. This ecological model is based on the Generalized Lotka Voltera equations that model the population evolution of species. These populations are controlled by biological factors (growth rate, carrying capacity and interaction among species), and by the environmental conditions (light, energy of the medium, nutrients, bottom slope and concentration of clastic sediments in suspension) which are combined forming a unique environmental factor that downscale the intrinsic rate of growth. The algorithm to apply in the code uses an explicit Runge-Kutta numerical method of order (4)5 to solve the differential equations formulated in the ecological model. Finally, a 3D visualization output files for the interpretation and analysis are generated using the VTK format. The obtained code has been applied in three sample experiments in order to discuss the possibilities and the limitations of the code. The first example is the model of a theoretical basin. The results are compared with real cases. The second example is an actual basin sited in western Mediterranean Sea. The results are discussed to show the applicability and the limitations of the model. The third example applies several configurations to the Aptian Galve sub-basin (Maestrat Basin, E Iberia), allowing to define the environmental conditions.

Recently observed cumulation of unexpected collapses of slope-distant waste dumps in lignite mining areas of eastern germany re-initiated research of soil liquefaction. Especially it turned the question of internal initials that correspond to water rise. Parallel to laboritory tests and field experiments a micromechanical model should be developed, which can reproduce processes in the soil during saturation. In first approximation a partly saturated soil consists of two phases: the soil particles and the pore fluid. For micromechanical modeling a coupling of discontinuum particles) and continuum (fluid) is required. The soil particles can be simulated with the Discrete-Element-Method (DEM). For the pore fluid, which is assumed to be a mixture of liquid and gaseous fractions, Pore scale model with Finite Volumes (PFV) is used. At low water content liquid bridges (meniscii) arise between the particles that cause an apparent cohesion. The effect of the meniscii is considered by a correspondingly contact law in the DEM model. During the saturation of a soil both, cohesive effect and fluid bulk modulus, are reduced. In addition buoyancy acts on the particles during the process. The micromechanical modeling approach has the advantage, that just a few model parameters are needed. The numerical model shows pore fluid pressures during saturation process, that leads to a reduction of effective stress. It is investigated how much the reduction is regarding porosity, degree of saturation, stress conditions and grain shape. Furthermore the influence of model parameters as well as hydromechanics is investigated. The investigations are completed with another series of experiments under special conditions like integration of macropores, horizontal fixed model boundaries and abrupt saturation.:Einleitung Literaturauswertung Numerische Modellierung Modellstudien Ergebnisauswertung Zusammenfassung Extended summary

Boreale Wälder in Permafrostregionen sind ein wesentlicher Bestandteil regionaler und globaler Klimamuster und machen etwa ein Drittel der weltweiten Waldfläche aus. Die Entwicklung der Waldbedeckung hat einen wichtigen Einfluss auf den Permafrost, da dieser durch die Vegetation geschützt wird. Der direkte Einfluss des Klimawandels auf die Wälder und der indirekte Effekt durch eine Veränderung der Permafrostdynamik können zu weitreichenden Ökosystemverschiebungen führen, die wiederum die Persistenz des Permafrosts beeinträchtigen und wichtige Ökosystemfunktionen destabilisieren könnten. Ziel dieser Dissertation ist es zu verstehen, wie sich die komplexen Wechselwirkungen zwischen der Vegetation, dem Permafrost und der Atmosphäre auf die Wälder und den darunterliegenden Permafrost auswirken. Im Rahmen dieser Dissertation habe ich ein eindimensionales, numerisches Landoberflächenmodell (CryoGrid), das zur Simulation der physikalischen Prozesse in Permafrostgebieten verwendet werden kann, für die Anwendung in bewaldetem Gebieten angepasst. Dazu habe ich ein detailliertes, mehrschichtiges Kronendachmodell (CLM-ml v0) und ein dynamisches Lärchenbestandsmodell gekoppelt. Dies ermöglichte den Energietransfer und das Wärmeregime welche für die komplexe Wald-Permafrost-Dynamik verantwortlich sind an verschiedenen Untersuchungsstandorten in gemischten und lärchendominierten Wäldern in Ostsibirien zu reproduzieren. Die numerischen Simulationen ergaben, dass die Wälder den thermischen und hydrologischen Zustand des Permafrosts hauptsächlich durch die Veränderung der Strahlungsbilanz und der Phänologie der Schneedecke beeinflussen und so eine stabilisierende Wirkung haben. Die Untersuchung der unterschiedlichen isolierenden Wirkung verschiedener Waldtypen und Walddichten sowie die Rückkopplungsmechanismen nach Störungen zeigen Veränderungen der thermischen und hydrologischen Bedingungen und der Tiefe der Auftauschicht. Zusammenfassend legen die Ergebnisse nahe, dass lokale, detaillierte und spezifische Landoberflächenmodelle erforderlich sind, um die komplexe Dynamik in borealen Permafrostökosystemen vollständig zu erfassen. Veränderungen der Rückkopplungen zwischen Permafrost, Klima, Wald und Störungen werden die eng gekoppelten Ökosystemfunktionen destabilisieren. Die induzierten Bodenveränderungen werden sich auf wichtige Wald- und Permafrostfunktionen, wie beispielsweise die Isolation des Permafrostbodens oder die Kohlenstoffspeicherung, und Rückkopplungsmechanismen wie Überschwemmung, Dürren, Brände, und Waldverlust, auswirken. / Boreal forests in permafrost regions make up around one-third of the global forest cover and are an essential component of regional and global climate patterns. The forests efficiently protect the underlying permafrost but the exact processes are not well understood. The direct influence of climatic change on forests and the indirect effect through a change in permafrost dynamics can lead to extensive ecosystem shifts, which will, in turn, affect permafrost persistence and potentially destabilize various ecosystem functions. The aim of this dissertation is to understand how complex interactions between the vegetation, permafrost, and the atmosphere stabilize the forests and the underlying permafrost. Within this dissertation, I have adapted a one-dimensional, numerical land surface model (CryoGrid), which can be used to simulate the physical processes in permafrost regions, for the application in vegetated areas by coupling a detailed multilayer canopy model (CLM-ml v0), and a dynamic larch stand model. An intensive validation of the model setup has allowed for the precise quantification of the heat- and water transfer processes responsible for the complex permafrost dynamics under boreal forest covers. At a variety of study sites throughout eastern Siberia, the numerical simulations revealed that the forests exert a strong control on the thermal and hydrological state of permafrost through changing the radiation balance and snow cover phenology. The forest cover has a net stabilizing effect on the permafrost ground below. The detailed physical model has furthermore enabled me to study the variation in insulation effect between different forest types and densities as well as the feedback mechanisms occurring after disturbances. In summary, the results suggest that local, detailed, and specific land surface models are required to fully comprehend the complex dynamics in boreal permafrost ecosystems. The research revealed that the feedbacks between permafrost, climate, boreal forest, and disturbances will destabilize tightly coupled ecosystem functions. The induced changes will affect key forest and permafrost functions, such as the forest's insulation capacity or the carbon budget, as well as feedback mechanisms like swamping, droughts, fires, or forest loss.

In dieser Arbeit wird anfangs dargestellt, wie kostenintensiv und problematisch die Kanalreinigung ausfällt. Durch die demographisch bedingt rückläufigen Schmutzwassermengen und gleichzeitig prognostizierten langen Trockenperioden in den Sommermonaten muss allerdings mit einer verstärkten Akkumulation von Ablagerungen in den Kanalsystemen gerechnet werden. Zudem erweist es sich in Voraussicht auf den Klimawandel als notwendig, den gesamten Kanalquerschnitt für Starkregenereignisse von Ablagerungen freizuhalten; ansonsten ist die häufigere Entlastung des Abwassernetzes in den Vorfluter nach Füllung der vorhandenen Regenrückhaltebecken vorprogrammiert. Die Kanalreinigung wird somit in den nächsten Jahren an Bedeutung gewinnen. Vor allem bei der Reinigung von Großprofilen ist jedoch der Stand der Technik noch nicht ausgereift und die jetzigen Reinigungsmethoden erweisen sich wegen des niedrigen Reinigungserfolges sowie der starken Umweltbelastung durch die genutzten Geräte als ungeeignet. Durch die in dieser Arbeit vorgestellte und auf den Stand der Technik gebrachte Reinigungsmethode wird jedoch eine leistungsstarke Alternative geboten. In Zukunft wird es möglich sein, große Kanaldurchmesser fast vollkommen umweltneutral zu reinigen und nur mit Hilfe der Wasserkraft das gesammelte Sediment bis zum nachgeschalteten Sandfang zu mobilisieren. Mit den durchgeführten und hier dargestellten numerischen Versuchen wird in erster Linie eine geometrische Optimierung zur Erreichung der größten Mobilisierungskräfte im Hinblick auf einen ausgewählten Abschnitt der Dresdner Kanalisation vollzogen. In der nachfolgenden physikalischen Modellierung wird der Schwerpunkt auf die optimale Reinigungsgeschwindigkeit gelegt, um ein möglichst großes Volumen an Ablagerungen zu bewegen. Es muss allerdings präzisiert werden, dass während der Modellierung kein Grenzzustand erreicht werden konnte. Dieser wird schließlich durch die folgende analytische Beschreibung des Transportvorganges theoretisch bestimmt. Für das genutzte physikalische Modell wird analytisch ein Grenztransportkörper aus Modellsediment errechnet. Bei einer Übertragung auf den dazugehörigen vorhandenen Abschnitt im Dresdner Kanalnetz durch Ansetzen des Ähnlichkeitsgesetzes wird ein mobilisierbares Grenzvolumen überschlagen. Die hier dargestellten Ergebnisse der theoretischen Untersuchungen bzw. der physikalischen Modellierung wurden mit den Betreibern und den Herstellern des neuen Stauwagens diskutiert und hinsichtlich konstruktiver Schwerpunkte optimiert. Unter besonderer Berücksichtigung der Kostenoptimierung und der konstruktiven Realisierung wurde von der Firma 'WKS Technik GmbH' ein Forschungsmuster zur Untersuchung in einer Pilottestphase entwickelt und gebaut. In der nachfolgenden dargestellten Testphase wurde das Ergebnis als Pilotprojekt im Dresdner Kanalnetz in mehreren Testläufen erprobt und untersucht. Nach jedem Testlauf wurden die aufgetretenen Probleme analysiert und durch Umbauten oder Veränderungen behoben. Regelmäßige Reinigungsfahrten sollten wegen der geringeren Ablagerungsmengen ein gleichmäßiges Fahren gewährleisten bzw. die Ablagerungen vollständig mobilisieren und bis zum Sandfang transportieren, um sie dort zu entnehmen. Während der Testphase wurde eine viel höhere Sedimentmenge gesammelt und transportiert als die, welche sich aus der analytischen Berechnung ergab. Dies folgte aus dem beim Naturversuch zugelassenen höheren Aufstauniveau hinter dem Spülwagen, welches ausnahmsweise zugelassen wurde, um auf eine zwischenzeitliche Sedimentabsaugung zu verzichten. / The early pages of this research thesis demonstrate how costly and problematic sewer cleaning is. Due to changing demographics causing declining amounts of wastewater and, at the same time, to predicted long dry spells during the summer months, an increased accumulation of sediments in the sewer systems has to be expected. With respect to climate change it is necessary to keep the entire sewer cross section free of sediments in order to manage heavy rainfall events; otherwise a more frequent relief of the wastewater system into the receiving water is inevitable once the rain retention basins have been filled. Thus sewer cleaning will gain in importance within the next few years. Predominantly the cleaning of large-diameter profiles, however, has not reached a state-of-the-art technology, and the current cleaning methods prove themselves to be inapt due to their very limited success as well as to the environmental burden posed by the equipment they employ. The state-of-the-art cleaning method presented in this research paper constitutes a high-powered alternative. In the future, it will be possible to clean large sewer cross sections almost entirely in an environmentally neutral fashion and to mobilize the accumulated sediment all the way to the downstream sand trap by exclusively harnessing water power. The numerical experiments conducted for this paper primarily effected a geometric optimization to achieve the maximal mobilization forces in a selected section of Dresden's sewer system. In the subsequent physical modeling the emphasis is placed on the optimal cleaning speed in order to move a maximum volume of sediments. It has to be clarified, however, that no limit state could be reached during the modeling procedure. This limit state is determined theoretically only through the following analytical description of the transport process. For the physical model at hand, the maximum transportable sediment volume made of model sediment is calculated analytically. In an extrapolation for the associated existent section in the Dresden sewer system, a mobilizable limit volume is estimated applying the law of similarity. The results of the theoretical analysis and the physical modeling presented in this work were discussed with the operators and manufacturers of the new storage vehicle and were optimized with regard to constructional core aspects. In special consideration of the cost optimization and the constructional realization, the 'WKS Technik GmbH' company developed and constructed a research prototype for a survey in a pilot test phase. During the subsequent test phase, the result was tried out and examined as a pilot project in several trial runs in Dresden's sewer system. After each trial run, the problems which had occurred were analyzed and then eliminated through constructional modifications or other alterations. Regular cleaning runs were intended to guarantee a steady movement of the cleaning vehicle due to a reduced amount of sediments, or to completely mobilize the sediments and transport them to the sand trap in order to remove them there. The sediment volume actually gathered and transported during the test phase was significantly larger than the one derived from the analytical calculation. This increase results from greater storage depths behind the flush car, which were permitted as an exception for the field test in order to go without any interim sediment extractions. / La prima parte della presente tesi di dottorato mette in evidenza le problematicità legate alla pulizia dei canali delle acque reflue, sottolineando in particolare gli enormi costi generati dall 'alta frequenza di depositi e dalla grandezza delle reti di raccolta presenti sui territori. A causa della riduzione demografica e delle condizioni meteorologiche che si stanno alterando, per il prossimo futuro si prevedono lunghi periodi di siccità, interrotti da acquazzoni intensi e brevi. Questo porterà ad un accumulo di depositi nelle reti di raccolta delle acque miste soprattutto nei mesi estivi, che implicherà a sua volta la necessità di tenere le sezioni dei canali presenti libere da depositi per consentire un appropriato deflusso e ritenzione in presenza delle suddette intense precipitazioni. Se in questi casi la ritenzione della rete fognaria non sarebbe data, infatti, si andrebbe a scaricare acque sporche sempre in maggiore quantità e con maggiore frequenza nei corsi d 'acqua di superficie, inquinando in secondo luogo anche le falde acquifere. Da questo quadro, si evince come la pulizia delle canalizzazioni acquisterà in futuro sempre una maggiore importanza. Attualmente, per la pulizia di canali di grandi dimensioni (maggiori di 1000 mm) non esistono metodi efficaci ed ecologici per movimentare i depositi presenti. Il presente lavoro espone una soluzione competitiva ai suddetti problemi. Grazie al lavoro di ricerca e sviluppo svolto, infatti, è stato elaborato un metodo con cui sarà possibile in futuro pulire canali di grosse dimensioni pressoché senza l\'impiego di energia esterna, ma solamente grazie all 'utilizzo dell 'energia dell 'acqua reflua presente nei canali, mobilizzando i depositi fino al prossimo punto presente dove sarà possibile estrarre dalla rete fognaria il materiale raccolto. L 'analisi numerica eseguita e qui rappresentata porta innanzitutto ad un 'ottimizzazione geometrica ed idraulica che consente il raggiungimento delle maggiori forze di mobilizzazione possibili per un segmento scelto della rete fognaria della città di Dresda (Sassonia). Nelle prove in laboratorio correlate si è cercato di ottimizzare la velocità con la quale deve avvenire la pulizia del fondo del canale in modo da poter trasportare il più elevato volume di sedimenti possibile. Si precisa a questo riguardo che in laboratorio non è stato possibile raggiungere il limite volumetrico correlato al modello fisico utilizzato, perché i soli 24 m di lunghezza del banco di prova non hanno consentito il raggiungimento di tale stato limite. Questo limite è stato determinato successivamente attraverso un modello analitico sviluppato appositamente, il quale descrive la mobilizzazione dei sedimenti attraverso la tecnologia di pulizia utilizzata. Attraverso i fattori di conversione che regolano le leggi fisiche presenti tra modello di laboratorio e natura è stato possibile in seguito rapportare il limite volumetrico al segmento reale utilizzato per le prove numeriche. Usando i risultati ottenuti sia dalle analisi numeriche che dalle prove di laboratorio è stato sviluppato e poi realizzato un prototipo assieme al partner commerciale 'WKS Technik GmbH', prestando particolare attenzione all 'ottimizzazione costruttiva e dei costi di produzione. Questo prototipo è stato testato per diverse volte in un tratto di circa quattro chilometri della canalizzazione di Dresda. Dopo ogni corsa sono stati analizzati i punti deboli del metodo di pulizia nonché del prototipo stesso e si è provveduto ad eliminarli. Gli ultimi test hanno confermato il funzionamento di tale prototipo offrendo inoltre una buona validazione del modello analitico sviluppato in precedenza.

This dissertation addresses the challenge of predicting human-induced subsidence in tectonic settings. The study focuses on the non-symmetric and shape-defying nature of subsidence troughs in tectonic regions, which deviates from conventional symmetric models. The aim of the dissertation is to improve the accuracy of subsidence prediction by incorporating horizontal stress effects into empirical methods. Through a combination of numerical investigations and empirical modelling, the research reveals stress-induced patterns in subsidence profiles. The developed model, based on various concepts, successfully incorporates asymmetry and shape deviation, resulting in significantly improved prediction accuracy. Application of the model to a real subsidence case in a salt cavern shows a 30% improvement in prediction (based on mean squared error comparison with classical solution). This new solution covers subsidence profile patterns not previously considered by empirical models.:Inhalt 1 Introduction 2 State of the art 2.1 Subsidence prediction methods 2.1.1 Empirical subsidence prediction method overview 2.1.2 Numerical methods for subsidence prediction 2.2 Subsidence monitoring methods 2.2.1 Observation methods 2.2.2 Interplay and evolution of techniques 2.3 Subsidence anomalies 2.4 In-situ-stress field 2.5 Subsidence prediction methods for anomalies 2.6 Conclusions 3 Goals and objectives 4 Foundations 4.1 Empirical subsidence prediction methods 4.1.1 Convergence 4.1.2 Transmission coefficient 4.1.2 Influence factor 4.2 Numerical models for subsidence case 4.2.1 Grid size for subsidence case 4.2.2 Boundary conditions 4.2.3 Constitutive models 4.3 Validation 4.3.1 Observation methods 4.3.2 Parameter estimation 4.3.3 Global parameter estimation 4.3.4 Local parameter estimation 4.3.5 Quality measures for result valuation and validation 5 Methodology 6 Numerical investigation 6.1 Preliminary investigation 6.1.1 Method 6.1.2 Choice of constitutive model 6.1.3 Model and input data 6.1.4 Preliminary investigation results 6.2 Design of the main experiment: non-uniform stress distribution 6.2.1 Constitutive model and input data 6.2.2 Model simplification 6.2.3 Output data 6.3 Contribution of asymmetrical stress distribution 6.3.1 Discussion of the basic distribution form 6.3.2 Discussion of maximum subsidence 6.3.3 Discussion of assymetry 6.3.4 Discussion of influence angle 6.4 Conclusions 7 Adaptation of an empirical model to the discovered features 7.1 Subsidence asymmetry 7.2 Subsidence shape flexibility 7.3 Unifying solution 7.4 Conclusion and outlook 8 Application to a full scale 8.1 General information for a salt cavern storage field 8.2 Estimation of the observed subsidence surface as reference 8.3 Model implementation 8.3.1 Parameter estimation results 8.4 Statistical validation of models 8.5 Conclusions 9 Conclusion 9.1 Limitations 9.2 Outlook References Appendix

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