Thesis (M. Dev. (Planning and Management)) -- University of Limpopo, 2021 / Sand mining has grown popular in South African rural communities due to its increasing demand for building purposes in and around the surrounding villages as well as a source of income to the rural communities. Sand is an indispensable natural resource of any society around the world. For instance, the government has to deal with the frequent sand mining environmental effects and implement various strategies on how to deal with these effects to protect the environment. Although the National Environmental Management Act (NEMA) 107 of 1998 regulates sand mining, the illegal and unregulated rural sand mining is causing land degradation, creating unpleasant appearances, causing vulnerability to floods and pointing out the need for rehabilitation. Given the circumstances surrounding the issue of illegal sand mining in rural communities, this research is aimed at investigating the impact of illegal or legal sand mining on the environment looking at the land degradation and the importance of rehabilitating the area after use in Mentz village. The main objective of this research was to explore how sand mining causes land degradation and examining the significance of rehabilitation in sand mining. The methodology of the study was carried out using both quantitative and qualitative research design in a form of questionnaire surveys, oral interviews and field observations to collect the data. The sample was composed of the general members of the community, the chief and the sand miners. For data analysis, the study used the Statistical Package for the Social Sciences (SPSS), IBM SPSS Statistics 25. The results indicated that sand mining causes 54.76% of the land degradation in South Africa. Furthermore, the research revealed that 30.95% of the land degradation was due to deforestation and 11.90% of Mentz land degradation was caused by overgrazing. Besides, an overwhelming 76.58% of the respondents agreed that land should be rehabilitated after sand mining processes.

Correct understanding of passive force behavior is particularly key to lateral evaluations of bridges because plastic deformation of soil backfill is vital to dissipation of earthquake energy and thermally-induced stresses in abutments. Only recently have studies investigated the effects of skew on passive force. Numerical modeling and a handful of skewed abutment tests performed in sand backfill have found reduced passive force with increasing skew, but previous to this study no skewed tests had been performed in gravel or Geosynthetic Reinforced Soil (GRS) backfills. The goal of this study was to better understand passive force behavior in non-skewed and skewed abutments with gravel and GRS backfills. Prior to this study, passive pressures in a GRS integrated approach had not been investigated. Gravel backfills also lack extensive passive force tests.Large-scale testing was performed with non-skewed and 30° skewed abutment configurations. Two tests were performed at each skew angle, one with unconfined gravel backfill and one with GRS backfill, for a total of four tests. The test abutment backwall was 11 ft (3.35 m) wide, non-skewed, and 5.5 ft (1.68 m) high and loaded laterally into the backfill. However, due to actuator loading constraints, all tests except the non-skewed unconfined gravel test were performed to a backfill height of 3.5 ft (1.07 m). The passive force results for the unconfined gravel test was scaled to a 3.5 ft (1.07 m) height for comparison.Test results in both sets of backfills confirmed previous findings that there is significant reduction in passive force with skewed abutment configurations. The reduction factor was 0.58 for the gravel backfill and 0.63 for the GRS backfill, compared to the predicted reduction factor of 0.53 for a 30° skew. These results are within the scatter of previous skewed testing, but could indicate that slightly higher reduction factors may be applicable for gravel backfills. Both backfills exhibited greater passive strength than sand backfills due to increased internal friction angle and unit weight. The GRS backfill had reduced initial stiffness and only reached 79% to 87% of the passive force developed by the unreinforced gravel backfill. This reduction was considered to be a result of reduced interface friction due to the geotextile. Additionally, the GRS behaved more linearly than unreinforced soil. This backfill elasticity is favorable in the GRS-Integrated Bridge System (GRS-IBS) abutment configuration because it allows thermal movement without developing excessive induced stresses in the bridge superstructure.

The aim of this Master Thesis is to investigate and quantify the climate impact for two floor system alternatives for the Cederhusen project, that is the 8 floors timber-based buildings located at Sankt Eriksplan in Stockholm. The overall motivation for this study is the fact that the construction industry is a major contributor to the total amount of the global greenhouse gas emissions. Therefore, in order to reduce these emissions new solutions, practices and applications must be adopted. An environmental attentive choice of materials used in structures has the potential of reducing the emissions. The first alternative is the existing floor system solution used by Folkhem. The second is a new type of floor system solution patented by Granab. Each floor system contains two segments: a structural part and a sub-floor part. The structural part in both alternatives contain an adding weight component to improve the dynamic performance of the relatively light weight high-rise timber buidlings. Both floor systems are thus so-called hybrid systems, where Folkhem's solution combines cross-laminated timber (CLT) and steel fiber reinforced concrete, and Granab's solution combines CLT and gravel. The specific objective was to compare the emission of greenhouse gases related to each floor system and their components by a so-called comparative life cycle assessment (LCA) methodology using a well-defined functional unit. The functional unit must consider all significant performance requirements obtained by the floor system, including load bearing capacity, dynamic performance, sound proofing, fire safety, surface flooring and maximum acceptable building height. The method of determining the climate impact is based on the “Anavitor Concept”, an innovative and digital approach to LCA calculations, to quantify and compare the environmental impact of the two floor systems through their lifetime, aiming for the user to not be an LCA expert, but to be the one who develops the design solutions, called “End-User”. Therefore, this concept performs direct LCA calculations from the BIM model by allowing access to environmental database, which contains life cycle analysis data approved and provided by LCA environmental specialists, and conveniently link material component against an industry-wide resource register receipt, called “Cross-Referencing”. The results show a significant decrease of climate impact with 33 % CO2e/m2 for the Granab’s alternative floor system compared to the existing floor system designed by Folkhem. Moreover, a direct comparison of the climate impact of Folkhem´s versus Granab´s adding weight system itself, shows a remarkable decrease of climate impact with 65 % CO2e/m2 emissions reduction for the Granab system.  Thera are several reasons for these remarkably results, however, the building material selection of gravel over concrete has the greatest influence. In practice, the ability to avoid the environmental impact of cement’s manufacture process in the production stage, A1-A3, is identified as the hot spot of this study. In addition, the environmental impact results signify the importance of a wise selection of the manufacturer and their factory location, mainly by selecting a factory located as close as possible. However, in practice, there are also other factors which need to be considered when choosing a supplier. Moreover, allowing the user to not be an LCA expert but to be the one who develops the design solutions, based on the “End-User” idea in the “Anavitor Concept” applied in this study, has novel benefits. By implementing LCA analysis during the architectural and structural design process, additional quantified environmental results can be instantly considered as additional causal numerical factors in the design process and directly affect executive decisions in earlier design stages for environmental matter as well. “Anavitor Concept” is a game changer regarding LCA in the construction sector. A future where every consulting building company around the globe would have access to open verified regulated environmental database and simply with their BIM model would be able to receive immediate quantified and verified environmental impact outputs in the early stages of design by the designers themselves and not LCA expert consultant, is an environmental dream come true. The “Anavitor Concept” should be adopted and expend outside the Swedish market and the environmental database should be adapted and modified to each national construction market around the globe.

"Reflection" is an experiment with what I call"symbolic architecture" i.e. design where the features of the building have a profound meaning or a strong recall to some familiar aspect in our lives. It is a meditation center designed to rejuvenate visitors by providing an ideal environment to practice and teach meditation. The design is inspired by concepts of Hindu philosophy and each element of the building, the light, the materials, the water and the structure is likened to an element of the spiritual being that helps a meditator achieve a connection between the body and the soul. / Master of Architecture

Vid röjning av RSV-ammunition saknas idag adekvat beslutstöd för att dimensionera skadebegränsande åtgärder mot jetstrålens verkan. I uppsatsen vidareutvecklas en beräkningsmodell som författaren tidigare föreslagit. Syftet är att skapa ett verktyg som kan införas i ammunitionsröjningsverksamheten. Fullskaliga skjutförsök har genomförts för att klarlägga inverkan av förhållanden som är typiska vid ammunitionsröjning; en skyddskonstruktion byggd av sandsäckar och med ett långt detonationsavstånd till röjningsobjektet. Försöksresultatet visar att den grundläggande hydrodynamiska penetrationsteorin inte är användbar för dessa förhållanden. Vidare ger sandsäckskonstruktionen signifikant bättre skydd mot jetstrålen än en homogen grusbädd. Genom störningsanalys har känsligheten hos de enskilda parametrarna i beräkningsmodellen för verksamhetstypiska fel utretts. Härefter har Monte Carlo-simulering använts för att analysera den sammanlagda inverkan som dessa fel kan ge. Resultatet har legat till grund för att bestämma modellens säkerhetsmarginal. Militär nytta innebär att modellen skall kunna tillämpas fältmässigt, med korta tidsförhållanden och utan tillgång till avancerade beräkningshjälpmedel. Detta har lett fram till att ett enkelt diagram inkluderats i det kompletta dimensioneringsverktyget. Verktyget föreslås införas i regelverk och utbildningssystem för att avhjälpa den brist som råder idag. / During the clearance of shaped charge ammunition, explosive ordnance disposal (EOD) personnel lack adequate means for the design of protective measures against the jet. In this thesis a calculation model, previously suggested by the author, is developed further. The aim is to create a tool that can be applied to EOD operations. Full-scale experiments have been conducted to clarify the effects of conditions that are typical for EOD operations: protective measures built from sandbags with a long standoff distance to the ordnance. The results indicate that the hydrodynamic penetration theory is not suitable for these conditions. Furthermore, a sandbag construction provides significantly better protection against the jet than a homogeneous gravel construction. By disturbance analysis, the sensitivity of the individual parameters in the model is studied for typical errors. Subsequently, Monte Carlo simulation has been used to analyse the effect these errors can cause. The simulation results have then been the used to determine the model´s margin of safety. Military utility implies that it should be possible to use the model under field conditions, with limited time frames and without access to advanced calculating means. This has resulted in a simple diagram included in the comprehensive design tool. It is proposed that the tool is implemented in regulations and curricula in order to remedy today’s lack of decision support.

Fine-grained sediment accumulation in the interstices of gravel beds is a key factor in degrading riverine habitats. However, interstitial deposits are highly dynamic and are not sufficiently understood. This work enhances the understanding of interstitial fine sediment deposition by investigating interstitial storage and ingress, flow, suspended sediment and gravel bed character. Furthermore, this work introduces a numerical suspended sediment deposition model with the power to predict patterns of interstitial ingress. The investigation of interstitial deposition were carried out on two levels. Both data orginating from flume experiments and from three locations of the River Culm, Devon, UK was collected. The experimental data showed the significant influence of small scale variations in flow and bed character and their influence on interstitial ingress. The field investigation showed clear differences in interstitial fine-grained sediment for the different river reaches and an overall higher interstitial ingress compared to recent published data. The numerical model development was realised in a two-step approach. First, the model was coded and calibrated for the flume scale processes and, second, an upscaled reach scale model was devolped for the field data. This reach scale suspended sediment deposition model included flow information, for which depthaveraged two dimensional hydrodynamic models were developed with the software Delft3D. The overall explanatory power of the model at this state is not satisfactory with regards to local deposition distribution. A separate chapter discusses the possible causes and implications of this short coming for further research from a data aquisition and modelling perspective.

Expériences de terrain et de laboratoire montrent que les rivières à gravier avec étendue granulométrique élevée et faible contrainte latérale, comme dans le cas des rivières à chenaux multiples, notamment les rivières en tresses, et des rivières à chenal unique avec une pleine mobilité latérale, comme les rivières à méandres, peuvent présenter simultanément variations du chenal actif à la fois dans le plan et dans la direction verticale, ainsi qu’un tri granulométrique planimétrique et vertical. En fait, les ajustements du chenal présentent une interaction complexe avec les processus de tri granulométrique: processus de transport et dépôt des mélanges de sédiments hétérogènes engendrent la formations de plusieurs motifs de tri, parmi lesquels patches qui migrent dans le chenal, notamment les sorting waves également connues sous le nom de bedload sheets. Ces sorting waves sont observées comme l’alternance des bandes de sédiments grossiers et fins dans la direction d’écoulement. Cette thèse de doctorat étudie les processus de tri granulométrique d’une distribution granulométrique bimodale à la fois dans la direction latérale et verticale avec un accent particulier sur l’étude des bedload sheets. Ce projet vise également à étudier les effets du confinement latéral sur la morphodynamique du lit de la rivière et en particulier sur les processus de tri granulométrique; et en plus, vu que le tri granulométrique joue un rôle crucial en influant sur le profil en long de la rivière, ainsi que les motifs sédimentaires et le formes du lit, étant donné le lien étroit entre la topographie du lit et la composition sédimentaire, pente, largeur du chenal actif et taux de transport des sédiments. L’analyse de ces paramètres permet de définir des feedbacks entre les variables morphologiques. Les résultats de cette étude éclairent le rôle de la contrainte latérale sur les processus de tri granulométrique et la morphodynamique du lit nu des rivières. / Field and laboratory investigations indicate that gravel bed rivers with poorly-sorted grain size distribution and low lateral confinement, such as in the case of multi-thread, braided and transitional rivers but also wandering single-thread rivers, can simultaneously present active channel variations, both in the planimetric and altimetric directions, together with planimetric and vertical sorting.Actually channel adjustments present a complex interaction with sorting processes. transport and depositional processes of heterogeneous sediment mixtures induce the formation of various sorting patterns, among which free migrating patches such as sorting waves also known as bedload sheets. Such sorting waves are mainly observed by the alternation of bands of finer and coarser material in the streamwise direction.This PhD research investigates the sorting processes of a bimodal grain size distribution both in the lateral and in the vertical direction, with particular focus on the study of bedload sheets.The main aim of this work is to investigate the effects of lateral confinement on river bed morphodynamics and in particular on grain sorting processes; and besides, given that grain sorting plays a crucial role in affecting longitudinal river profile, as well as sediment patterns and bed forms, being indeed the connection between bed topography and bed sediment composition close, we would like to provide simple theoretical analyses and tools able to predict morphodynamic bed river variations driven by sortingDifferent methodologies are applied to successfully achieve this purpose.Firstly, a deep investigation of the state of knowledge of mixed-size sediment morphodynamics, sorting processes, sorted sediment patterns and bedload sheets is carried out.Then, a 1D linear stability analysis of a uniform flow above an erodible bed composed by a bimodal mixture of sediments is performed and investigation of the associated eigenvectors, amplitude of perturbations and migrations rate is discussed. Results are presented in terms of arising instabilities dominated by sorting. Although the monodimensional shallow-water framework, the simple flow model adopted allows for the formulation of an algebraic eigenvalue problem that can be solved analytically, allowing for a deep insight into the mechanisms that drive instabilities.Then, small scale flume experiments are carried out by reproducing three different flow confinement configurations and involving a bimodal mixture of natural sediments. All the configurations show large fluctuations of parameters characterising bed system in terms of bed sediment composition, slope, active channel width and sediment transport rate. The analysis of such parameters allows defining feedbacks among morphological variables. Results of such investigations shed light on the role of lateral confinement on sorting processes and morphodynamics of barebed rivers.

The aim of this study was to develop and examine the use of backscatter data collected with multibeam sonar (MBS) systems for benthic habitat mapping. Backscatter data were collected from six sites around the Australian coastal zone using the Reson SeaBat 8125 MBS system operating at 455 kHz. Benthic habitats surveyed in this study included: seagrass meadows, rhodolith beds, coral reef, rock, gravel, sand, muddy sand, and mixtures of those habitats. Methods for processing MBS backscatter data were developed for the Coastal Water Habitat Mapping (CWHM) project by a team from the Centre for Marine Science and Technology (CMST). The CMST algorithm calculates the seafloor backscatter strength derived from the peak and integral (or average) intensity of backscattered signals for each beam. The seafloor backscatter strength estimated from the mean value of the integral backscatter intensity was shown in this study to provide an accurate measurement of the actual backscatter strength of the seafloor and its angular dependence. However, the seafloor backscatter strength derived from the peak intensity was found to be overestimated when the sonar insonification area is significantly smaller than the footprint of receive beams, which occurs primarily at oblique angles. The angular dependence of the mean backscatter strength showed distinct differences between hard rough substrates (such as rock and coral reef), seagrass, coarse sediments and fine sediments. The highest backscatter strength was observed not only for the hard and rough substrate, but also for marine vegetation, such as rhodolith and seagrass. The main difference in acoustic backscatter from the different habitats was the mean level, or angle-average backscatter strength. However, additional information can also be obtained from the slope of the angular dependence of backscatter strength. / It was shown that the distribution of the backscatter. The shape parameter was shown to relate to the ratio of the insonification area (which can be interpreted as an elementary scattering cell) to the footprint size rather than to the angular dependence of backscatter strength. When this ratio is less than 5, the gamma shape parameter is very similar for different habitats and is nearly linearly proportional to the ratio. Above a ratio of 5, the gamma shape parameter is not significantly dependent on the ratio and there is a noticeable difference in this parameter between different seafloor types. A new approach to producing images of backscatter properties, introduced and referred to as the angle cube method, was developed. The angle cube method uses spatial interpolation to construct a three-dimensional array of backscatter data that is a function of X-Y coordinates and the incidence angle. This allows the spatial visualisation of backscatter properties to be free from artefacts of the angular dependence and provides satisfactory estimates of the backscatter characteristics. / Using the angle-average backscatter strength and slope of the angular dependence, derived by the angle cube method, in addition to seafloor terrain parameters, habitat probability and classification maps were produced to show distributions of sand, marine vegetation (e.g. seagrass and rhodolith) and hard substrate (e.g. coral and bedrock) for five different survey areas. Ultimately, this study demonstrated that the combination of high-resolution bathymetry and backscatter strength data, as collected by MBS, is an efficient and cost-effective tool for benthic habitat mapping in costal zones.

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