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This article presents an investigation of ground movement measurements based on a combination of TerraSAR-X and Sentinel-1 data, in opposite tracks, aiming to detect ground de-formation of the remaining dikes of Germano mine, after the Fundão dam collapse. The differential interferometry technique SBAS (Small Baseline Subset) was applied to obtain the deformation of the surface in different Line of Sight (LoS), in order to carry out the vector decomposition and generate the deformation measurements in the vertical and horizontal directions. A set of 37 single-look complex (SLC) images of TerraSAR-X (TSX), acquired during the period from 19 February 2016 to 15 May 2017, and 37 SLC images of Sentinel-1, acquired from 8 February 2016 to 15 May 2017, were used to perform this investigation. For the TerraSAR-X interferometric processing, a coherence threshold of 40%, 4 looks in range and 2 looks in azimuth, 1200 m of atmospheric filter, and 10 % of max normal baseline of the critical were used. For the Sentinel-1 interferometric processing a coherence threshold of 26%, 8 looks in range and 2 looks in azimuth, 1200 m of atmospheric filter, and 20% of the of max normal baseline of the critical were used. For both sensors a digital elevation model generated by Pleiades 1-A was used for removing the topographic phase component. The final results were consistent with the topographic in situ measurements, providing key information to make crucial decisions regarding risks, or even mitigation, repairs or emergency response, as well as for a better understanding of the on-going instability phenomena affecting the dikes and dams. [ABSTRACT FROM AUTHOR]

The net tectonic rotation method is an alternative to paleomagnetic tilt corrections. The method was originally developed for sedimentary rocks and lavas, which have paleohorizontal indicators, but was later adapted for dikes by assuming that dikes intrude vertically. We conduct multiple numerical experiments that demonstrate geometric flaws in the net tectonic rotation method if dikes are not quite vertical prior to deformation. These flaws can impact the interpretations from the method, but the size of the impact depends on the original dike strike, dike dip, and the paleomagnetic reference direction. Our experiments show the worst behavior occurs for dikes that are approximately perpendicular to the reference declination. In addition, the results for dipping dikes of all initial strikes become increasingly distorted as the reference direction's inclination increases. Using data from two field areas in Cyprus and northern Iceland, we compare the application of net tectonic rotation to alternative techniques—relative comparisons and spatial regressions—that do not require an assumption of initially vertical dikes. We conclude with a list of questions that workers should answer prior to future application of net tectonic rotation to dikes. Plain Language Summary: A dike is a tabular intrusion of volcanic rock. It may record the direction of Earth's magnetic field at the time of the dike's formation, and it may subsequently rotate due to tectonic processes. By analyzing the magnetic content of a dike, a geologist can therefore acquire information about Earth's tectonic history. Net tectonic rotation is a particular technique for acquiring such information. It assumes that dikes are vertical at the time of their intrusion. We perform experiments that show that if dikes are not quite vertical, the inferences from this technique will be flawed. The flaws are not systematic and in some cases can lead to egregious errors in the interpretations. We show some alternatives to this approach using real data from Cyprus and northern Iceland. We also list a series of questions for workers to consider if they wish to use this method in the future. Key points: The net tectonic rotation method has been used to predict initial dike strikes from paleomagnetic dataThe method assumes that dikes are initially vertical and can return the correct dike strike in these casesNumerical experiments show the method returns biased answers for dipping dikes that may impact geologic interpretations [ABSTRACT FROM AUTHOR]

We present two analytical solutions for the boundary-value problem of a homogeneous, isotropic, and linear elastic solid with a vertical fluid-filled crack, and use these to investigate the effects of gravitationally induced stress and pressure gradients on the opening distribution, fracture-tip stress intensity, and stable heights of veins and dikes. Stable fractures are not propagating or closing anywhere along their tipline, so the vein or dike is in its final arrested configuration as preserved in the rock record. The solutions do not preclude interpenetration of crack surfaces, so we propose special constraints to avoid such ill-posed problems. Veins and dikes both grow as fluid-filled, opening fractures in Earth's brittle lithosphere, but attain markedly different heights. We show how gravity-induced pressure gradients in water and magma, and stress gradients in the host rock, lead to different stable heights. Dikes, but not veins, can attain stable heights near the level of neutral buoyancy in a density stratified rock mass, even if the host rock fracture toughness is zero. Depth to center and opening distributions for dikes are different if host rock density is stratified or continuously variable. These solutions offer a new set of analytical tools for interpreting field data from veins and dikes. [ABSTRACT FROM AUTHOR]

In this study a new method is presented to determine model parameters from magnetic anomalies caused by dipping dikes. The proposed method is applied by employing only the even component of the anomaly. First, the maximum of the even component is divided to its value at any distance x in order to obtain S1. Then, theoretical even component values are computed for the minimal depth ( h) and half-width ( b) values. S2 is obtained by dividing their maximum to the value computed for the same distance x. A set of S2 values is calculated by slowly increasing the half-width, and h and b for the S2 closest to S1 are determined. The same procedure is repeated by increasing the depth. The determined b values are plotted against the corresponding values of h. After repeating the process and plotting curves for different distances, it is possible to determine the actual depth and half-width values. [ABSTRACT FROM AUTHOR]

Since mankind exists, men have undertaken engineering activities to make their life more pleasant and secure. However this has not been an easy task, especially in the past. The knowledge of mathematics and physics to describe engineering problems became available only since 1400-1500. Nevertheless, great achievements have been made by man before that time, e.g. the pyramids in Egypt, the first sluice in China, the Borobudur temple in Indonesia, and the design and building activities of the Inca's in South America. To illustrate this development, also the world economy, world ecology will be shortly mentioned. The structures that are briefly discussed in this paper are: soil and concrete dams for generating electricity, reservoirs for irrigation and drinking water, dikes, sluices, inland and sea, tunnels, and quay walls. This paper presents an overview of hydraulic structures in general with the emphasis on quay walls and dikes in the Netherlands. Examples of these structures will be discussed illustrating present state of the art and also with a view to the future. Conclusions and recommendations are given to enhance the knowledge of hydraulic structures. [ABSTRACT FROM AUTHOR]

Dike risk management requires breaching parameters that can be estimated rapidly to support the prediction of inundation zones and decision making. The objectives of this paper are to compile a database of dike breaching cases, study common dike failure mechanisms, and develop a set of empirical equations for estimating breaching length, depth, and peak discharge. A database of over 1,000 dike failure cases was collected, with information on pre-breach dike geometry, materials, type of dike, failure mechanisms, breaching length, depth, and peak discharge. A set of regression models are formulated using five control variables: dike height, width, material, type of dike, and failure mechanism. The standard error is set as a selection criterion and the Akaike information criterion is used to optimize the proposed empirical models. The new models are validated using independent cases and compared with available empirical equations for dikes and man-made dams. [ABSTRACT FROM AUTHOR]

The cost of upgrading and raising coastal defences is an important consideration in societal response to sea-level rise. Currently available unit cost estimates have a limited empirical basis. This article presents new information on the unit costs of adapting coastal defences for three specific case studies in low-lying delta regions: The Netherlands, New Orleans, and Vietnam. Typical measures include dikes, flood walls, storm surge barriers, and nourishment. These unit cost estimates are significantly higher than earlier estimates that are still the main source of costs for global vulnerability assessments. Factors affecting these unit costs include local economic factors (material and labour costs), design choices related to the alignment of the system, and the types of measures for implementation of the system in an urban or rural environment. On the basis of an example for a Dutch sea dike, it is shown that the material quantities and associated costs are expected to rise linearly, in the case of depth-limited wave breaking, for the range of sea-level rise rates that are expected in the coming century. However, other factors, such as increasing costs for implementation of wider coastal defences in an urban environment and future changes in material and labour costs, could contribute to a nonlinear increase of the costs. Further collection and analysis of project information for coastal defence projects in other regions is recommended to strengthen the empirical basis of the cost estimates that are used for regional and global assessments. [ABSTRACT FROM AUTHOR]

This paper determines the optimal timing of dike heightenings as well as the corresponding optimal dike heightenings to protect against floods. To derive the optimal policy, we design an algorithm based on the Impulse Control Maximum Principle. In this way, this paper presents one of the first real-life applications of the Impulse Control Maximum Principle developed by Blaquière. We show that the proposed impulse control (IC) approach performs better than dynamic programming with respect to computational time. This is caused by the fact that IC does not need discretization in time. [ABSTRACT FROM AUTHOR]

The three-dimensional turbulent flow field around a spur dike in a plane fixed-bed laboratory open channel was studied experimentally using a microacoustic Doppler velocimeter. Mean and turbulence characteristics in all three spatial directions were evaluated at upstream and downstream cross sections near the dike. Results showed that the primary flow separated in both lateral and vertical directions. Two counter-rotating flow circulations, consisting of the lateral and vertical velocity components, originated at the dike section. Downstream of the dike, the circulation in the flow-separation zone is stronger than the one in the contracted primary flow zone. The maximum bed-shear stresses estimated using Reynolds stresses is about three times as large as the mean bed-shear stress of incoming flow. [ABSTRACT FROM AUTHOR]

This paper describes the stability of the west perimeter dike at the Craney Island Dredged Material Management Area (CIDMMA) using an undrained strength stability analysis. An undrained strength stability analysis expresses the undrained shear strength in terms of the effective overburden stress of the dredged material and the marine clay underlying the dike. An undrained strength stability analysis was used to evaluate the current stability of the west perimeter dike, the possibility of raising the perimeter dike, and the effect of undrained strength increase along with full consolidation by installing vertical strip drains on the current stability and the potential for raising the dike. Vertical strip drains would accelerate consolidation of the confined dredged material and underlying marine clay and thus produce an increase in undrained shear strength and dike stability. The analyses show that installation of vertical strip drains and full consolidation of the dredged material and underlying marine clay should allow the perimeter dike and dredged material to be raised and an increase in CIDMMA service life. [ABSTRACT FROM AUTHOR]

Sand compaction piling is one of the commonly used countermeasures for earthquake liquefaction hazard of river dikes. This paper presents a case study of the performance of an instrumented dike in northeast Japan that was improved by sand compaction piles and subjected to the 2003 Northern Miyagi Earthquake, with the aim to better understand the effectiveness of this ground improvement method. Simulation has been carried out by means of a fully coupled numerical procedure which employs a sophisticated cyclic elastoplastic constitutive model and the updated Lagrangian algorithm. Comparisons between the field measurements and the computed responses, including the time histories of accelerations and pore-water pressures at different locations, show reasonably good agreement. Numerical simulation has also been made of the same dike but without ground improvement to identify the effects of sand compaction piles in altering the performance of the dike. The study demonstrates that the comprehensive numerical procedure is a promising tool for development of seismic performance-based design of earth structures. [ABSTRACT FROM AUTHOR]

To improve knowledge of the flow and scour processes associated with spur dikes, three-dimensional flow velocities were measured at 2,592 points using an acoustic Doppler velocimeter over a fixed flat bed with a trapezoidal shaped submerged spur dike in a laboratory flume. General velocity distribution and detailed near field flow structures were revealed by the measurements and numerical simulations performed using a free surface turbulent flow model with a k–[variant_greek_epsilon] closure scheme. The three-dimensional flow separation characterized in this study was found to yield forces on the bed that were significantly different from nonsubmerged vertical obstructions that have been measured in other studies. Values of bed shear stress derived from both measured and simulated values were similar but indicated that local scour would be initiated in one rather than in the two locations of initial local scour measured in previous experiments with a similar flow. [ABSTRACT FROM AUTHOR]

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A solitary wave interacting with a bottom mounted rectangular dike was studied experimentally using the quantitative particle image velocimetry (PIV) technique and two qualitative flow visualization techniques, including the laser induced fluorescence technique and the particle tracing technique. Vortices were generated due to flow separation at the corners of the dike, and shed downstream and upward by the induced current. The vortex shedding processes were identified using the two qualitative visualization techniques while detailed velocity field was measured quantitatively using PIV. Detailed vortical structures in the vicinity of the dike were investigated and compared with observations in other studies. A greater than expected number of vortices were generated at both sides of the dike and observed through detailed flow visualization. A similarity profile similar to a turbulent jet was found for the flow on the lee side of the dike. [ABSTRACT FROM AUTHOR]

This paper presents a case study detailing a riverbank dike damaged by pile driving in very soft clay in Shanghai, P. R. China. Driven piles were designed to support the existing dike to be raised to a higher elevation. The subsoil mainly consisted of very soft clay with its natural moisture content greater than its liquid limit. This paper describes the phenomena of dike movement and crack development during pile driving based on field observations and instrumentation data. Cone penetration tests and vane shear tests were conducted after pile driving to investigate the slip surfaces. Degradation of soil strength was identified as the main cause for the failure of this dike. Slope stability analysis was conducted to back-calculate the degraded undrained shear strength of the clay. The results indicate that the soil strength in the disturbed area due to pile driving approached the level of its remolded strength. [ABSTRACT FROM AUTHOR]

Uplift induced slope failure occurs due to high water pressures in the sand layer below the soft top layers in a polder. The top layers are lifted due to water pressure invoking slope instability. The mechanism is significant in the Dutch lowlands. In this paper a new stability design model has been presented and corresponding geocentrifuge testing, a full-scale field test, and numerical validation are discussed, as well as the influence of the human factor. Comparisons of the new model with four existing models are shown for ten Dutch representative polder dikes. Furthermore, safety aspects are discussed and conclusions are drawn. The new design model has been incorporated in the Dutch national guideline for dike design. [ABSTRACT FROM AUTHOR]

This paper presents the findings from a series of flume experiments conducted to determine scale effects in small-scale models of flow around a single spur dike (wing-dam, groyne, or abutment) placed in a channel whose bed is fixed and flat. The flow features of primary interest are flow-thalweg alignment (line of maximum streamwise velocity) around a dike, and area extent of the flow-separation region (wake) immediately downstream of the dike. Those features are of practical concern in the deployment of dikes for various channel control purposes. The scale effects of concern herein are those attributable to use small length scales together with a bed-shear stress parameter (e.g., Shields parameter) as the primary criterion for dynamic similitude. Small-scale models, especially micromodels, often are used for investigating channel-control issues. Also, the shear-stress criterion is commonly used for models of flow in loose-bed channels, whereas Froude number commonly is the primary similitude criterion for models of fixed-bed open-channel flows. The experiments show that use of a shear-stress parameter as the primary criterion for dynamic similitude influences the flow thalweg and flow separation region at a dike. It does so by distorting pressure gradients around the model dike and by affecting turbulence generated by the dike. It also is shown that, for a range of small models, thalweg alignment and extent of separation region do not scale with model length scales. These findings are important for interpreting results from small hydraulic models, especially micromodels, of flow in loose-bed channels. [ABSTRACT FROM AUTHOR]

Experience with use of ash-slurry wastes from thermal electric power plants and coal-dressing mills of a metallurgical combine as a base for tailing ponds during the building of enclosing dikes is described. Results are cited for investigations and experimental-industrial tests of dikes constructed of blast-furnace wastes. [ABSTRACT FROM AUTHOR]

Dismembered ophiolites on the Southern Aegean islands of Crete, Karpathos and Rhodes link the Jurassic ophiolites of the Hellenides (e.g., Pindos, Vourinos) and the Cretaceous ophiolites of the Taurides in southern Turkey (e.g., Antalya). The ophiolites of these islands do not form a continuous belt. There are significant differences in composition and age between the ophiolites of Crete in the west and those of Karpathos and Rhodes in the east.Crete: Peridotite relics in serpentinites are lherzolitic with high concentrations of Al2O3 and CaO (mean values of 2.7 and 2.0 wt.%, respectively). Spinels in these rocks are as rich in Al2O3 as those in fertile peridotites from orogenic lherzolite massifs. These rocks represent primitive, undepleted mantle material, indicating an origin at a slow-spreading ridge. The Cretan peridotites are intruded by gabbroic dikes ranging in composition from pyroxene gabbros to hornblende diorites and plagiogranites. The dominance of hornblende in these rocks and the geochemical signature indicate a subduction-related origin for these dikes. Hornblendites associated with the peridotites are regarded as metamorphic ferrogabbros, which were probably overprinted in high-temperature shear zones. K–Ar dating of hornblendites yielded ages around 160 Ma (Middle to Late Jurassic), indicating that these ophiolites are a part of the Jurassic ophiolite belt of the Balkan peninsula. Around 20 Ma younger K–Ar ages were derived for the gabbroic dikes within the peridotites.Karpathos and Rhodes: The peridotite relics in serpentinites from Karpathos and Rhodes are very low in Al2O3 and CaO and correspond to depleted harzburgites. The ultramafics are intruded by dolerite dikes which are very uniform in composition. The dikes show a trace element signature typical of island arc basalts. Both the depleted nature of the peridotites and the geochemistry of the dikes are typical of supra-subduction zone ophiolites. K–Ar dating of hornblendes from the dolerites yielded an early Late Cretaceous minimum age (around 90 Ma) for the ophiolites of the two islands. Both age and the remarkable similarity in composition and structure to ophiolite occurrences in southern Turkey demonstrate that the ophiolites of Karpathos and Rhodes belong to the Cretaceous ophiolite belt of the Eastern Mediterranean and the Middle East. [Copyright &y& Elsevier]

A series of effective stress analyses is carried out on the seismic performance of river dikes based on the case histories during the 1993 Hokkaido-Nansei-oki and 1995 Hyogoken-Nambu earthquakes in Japan. Seven case histories selected for the analyses involve a crest settlement ranging from none to 2.7 m in the dikes 3–6 m high with evidence of liquefaction at foundation soil. The effective stress model used is based on a multiple shear mechanism and was developed by one of the authors. The soil parameters are evaluated based on the site investigation and laboratory test results. The results of the analyses are basically consistent with the observed performance of the river dikes. In particular, the effective stress model shows a reasonable capability to reproduce the varying degree of settlements depending on the geotechnical conditions of foundation soils beneath the dikes. The analyses also indicate that the effect of a cohesive soil layer mixed with the liquefiable sand layers beneath the dikes can be a primary factor for reducing the liquefaction-induced deformation of dikes. [Copyright &y& Elsevier]

The seepage rate through homogeneous or zoned dikes includes saturated and unsaturated flow. The latter is often neglected but should be considered to obtain the positions of the water table and the seepage face that may develop either on the downstream slope of a homogeneous dike or within the filter layer behind the core of a zoned dike. Different dikes with heights of 5, 10, 20, and 50 m have been analyzed numerically with a two-dimensional finite element code. The cases investigated include the most frequent types of small dikes designed to retain municipal or industrial wastewater. Solutions are proposed to solve numerically two difficulties related to the representation of saturated and unsaturated physical flow conditions. One difficulty is treating a downstream seepage face. The other is treating the passage of water from the core into a draining layer. The paper presents simple expressions to predict the total (saturated and unsaturated) seepage flow rate through a dike and discusses precautions to be taken.Key words: dams, dikes, seepage, saturated soil, unsaturated soil, numerical modeling.Le débit de fuite des digues homogènes ou zonées inclut les écoulements saturés et non saturés. Ces derniers sont souvent négligés mais devraient être considérés pour avoir les positions de la nappe et de la surface de suintement qui peut se développer sur la pente aval d'une digue homogène ou dans le filtre à l'arrière du noyau d'une digue zonée. Différentes digues de hauteurs 5, 10, 20 et 50 m ont été analysées numériquement avec un code bidimensionnel d'éléments finis. Les cas étudiés comprennent les types les plus fréquents de petites digues conçues pour retenir des eaux usées municipales ou industrielles. On propose des solutions pour résoudre numériquement deux difficultés reliées à la représentation des conditions physiques d'écoulement saturé et non saturé. Une difficulté est le traitement d'une surface de suintement. L'autre est le traitement du passage de l'eau du noyau dans une couche drainante. L'article propose des expressions simples pour prédire le débit de fuite total (saturé et non saturé) à travers une digue et discute des précautions à prendre.Mots clés : barrages, digues, écoulement, sol saturé, sol non saturé, modèle numérique. [ABSTRACT FROM AUTHOR]