Two different problems of optimization in the utilization of geothermal energy are presented: First, the thermodynamic optimization for a geothermal power plant using a single- or double-flash process is considered; in this analysis, the optimum flash temperature giving the maximum power output is determined. Second, an economic optimization for space heating systems using geothermal energy is developed to obtain operating conditions for which the total (capital and operating) cost is a minimum. Both graphical and analytical methods are used in the thermodynamic optimization to determine the optimum flash temperature. The graphical method is based on thermodynamic data provided by an i-s (enthalpy-entropy) diagram for water and steam, in the analytical method, first and second order approximations (first and second degree polynomial approximations), are used for the functions which express enthalpy differences in terms of flash temperature. Numerical results are provided by computer programs developed for the analytical method. These results cover the temperature range normally encountered in practice. In the case of the single-flash cycle, results from both the graphical and analytical method using the first order approximation indicate the same optimum flash temperature; however, the correction factor resulting from the second order approximation improves the value of the temperature by a correction of about -2 ° C. Optimum flash temperatures for the double-flash cycle are similarly determined using the analytical method with a first order approximation. In the economic optimization of space heating systems, the analysis is made on the basis of the annual total cost per unit area of wall surface. It takes into account the cost of the geothermal fluid, cost of wall insulation, and heat exchanger cost. For a specific case where the inlet temperature to the heat exchanger is at 100° C and the outlet temperature at 28° C, the minimum annual cost to maintain a space at 20°C with an outside temperature of -l0°C is given at $0.0257 per square meter of wall area while the optimum thickness for the wall insulation is 0. 126 meter. Additional improvement in the optimization of flash temperature can be made by using a second order approximation method for the double-flash power cycle.

Freezing-thawing, changes the properties of soil due to the phase change of the water in the soil body. Freezing-thawing cycles in the soil have been studied for several decades including extensive laboratory research. In this study, the main focus is thawing based on laboratory investigation. The soil used in the laboratory study is taken from a minor road where an additional field study has been carried out. A freezing-thawing laboratory apparatus is manufactured and used in order to get better understanding of the freezing-thawing process. The apparatus is designed for cylindrical sample, one dimensional heat flow, freezing/thawing from top to bottom, water supply from bottom (access to external water) and possible to apply overburden load. he laboratory tests were conducted at similar soil samples at different boundary conditions. Water is liberated in the thawing zone of the sample. During thawing the only drainage path is to the surface, however, water migrates upwards even when entire soil is thawed. Upwards water migration after thawing period can be due to the changes in thawed soil properties such as permeability and fine particles redistribution. The rate of thawing is a very important factor for thawing conditions. At low thawing rate the drainage capacity of sample is sufficient to drain the liberated water from ice. Moreover, freezing condition i.e. access to water, has high impact on thawing process. If the volume of ice lenses is high,the thawed soil fluidizes as the water migrates upwards. Pore pressure transducers will be added to the apparatus for further investigation regarding both freezing and thawing. The field study has been conducted in order to study thaw behavior in low volume road embankment. The scope of the study is to investigate the thaw weakening progress by Falling Weight Deflectometer (FWD) and Dynamic Cone Penetration (DCP) tests on low volume embankment road near Luleå,northern Sweden. The results from methods is compared and the differences in how they are capturing the thawing is discussed. DCP which is known as an easy and cheap method to estimate stiffness of soil layers is applied to estimate thawing period and the layer which thaw weakening takes place at. Stiffness gained by back calculation of FWD results which is performed on the same road embankment and same period of time DCP test is done. / Tjällossningsegenskaper för överbyggnadsdimensionering

Ultra-high performance concrete (UHPC) is an emerging cementitious material type currently undergoing research in different structural applications. This material is characterized by a compressive strength of 150 MPa (22 ksi), according to the Association Francaise de Genie Civil and the Federal Highway Administration, high tension strength, and high durability. Additionally, UHPC consists of secondary reinforcement in the form of steel or polymeric fibers, which enable UHPC to exhibit tension hardening behavior and tension ductility previously ignored in conventional concrete mixes. Previous research has focused on applications in the transportation and bridge design industries; however, applications in buildings and other heavy construction projects necessitate a better understanding of shear and flexural-shear failure modes in design recommendations and guidelines. The purpose of this research is to test a series of UHPC specimens to investigate the shear failure responses in beams. Additionally, this research will also investigate the tensile properties of UHPC to assist in determining the relevant shear properties. Two series of specimens were created for testing: small-scale beam specimens for load-displacement behavior analysis under four-point bending and UHPC prisms for determining the effects of tension stiffening. Both sets of specimens were created using ASTM Grade 60 steel and high strength steel for the primary reinforcement. Finally, numerical analyses using finite element analysis software, based on both continuum and macroelement models, of the UHPC specimens were carried out based on the modified compression field theory (MCFT) to verify and expand upon the experimental results. Results of the UHPC tension stiffening experiments were normalized to obtain an averaged tensile stress for UHPC in tension in the presence of primary reinforcement. The calibrated tension stiffening responses were used in the numerical analyses. The beam specimens exhibited the combined failure mode of shear-flexural failure in all of the specimens. Additionally, slight concrete crushing at the top of the specimens was noted at larger displacements. No purely flexural failures were observed, as would be expected in normal strength concrete. The numerical analyses were able to predict the load-displacement behavior and failure modes of the experimental UHPC beam specimens with acceptable accuracy. Further numerical analyses were then conducted to determine the effects of different UHPC strengths, aspect ratios, and reinforcement ratios. These analyses provide insight on the transition between flexural and shear failure modes for different design properties.

Structured and long-term planning is an important part of the work with the renewal of water supply networks. This requires well-founded assessments and methods for evaluating the annual need for renewal for a sustainable and healthy future. Evaluating the condition of a management object has been a complex task. This is due to limited accessto the various parts of the water supply network and the fact that physical, operational and environmental factors affect pipelines in different ways. Since experience and knowledge have been developed about, for example, joint methods or the durability of pipe material, this has meant that several different pipe materials are underground. There are various useful methods for evaluation of the condition of the water supply network. Recently, mathematical models have begun to be used to analyse the status and estimated lifespan of lines through data on pipes and external factors. In this study, an ANN model from Svenskt Vatten was used to evaluate the organization’s geodata for the model and to study the relationship between risk management that models calculate and reported operational disruptions. The use of the model requires that large amounts of data need to be compiled and adapted to valid values.The results show that most of the water supply network in the study area can be used to set prediction values with the model by compiling and adapting attribute values. Several objects were excluded due to deficiencies in management attributes. Some comparisons can be made between estimated risk water pipes and reported operational disruptions. The conclusion of the study is that the model could be an important complement to future renewal planning. Assessed risk water pipes can provide a good indication of which parts of the pipeline network need to be evaluated in more depth for possible renewal.

Florida might be one of the most sinkhole-active areas on the earth. Due to its unpredictability and significance of occurrence, the development of sinkhole monitoring techniques is imperative to minimize sinkhole-induced hazards. Several methods have been used to evaluate sinkhole risks, including destructive methods, such as Standard Penetrating Tests (SPT) and Cone Penetrating Tests (CPT), geophysical method, and sensor-based groundwater monitoring method. However, few studies are available for comprehensive understanding of spatiotemporal sinkhole mechanism by combining different exploration methods under realistic experimental conditions. The objective of this study is to understand spatiotemporal sinkhole mechanism, using SPT, CPT, ground penetrating radar (GPR), and piezo pressure sensors tested at actual sinkhole sites. A small-scale test was conducted prior to the field test to validate data analysis technique using piezo pressure sensors, developed in this study. Eight piezo pressure sensors were used located at different distances from the sinkhole center to measure the ground water levels (GWLs) during artificially made sinkhole events. A total of 24 scaled tests was conducted with different sinkhole soil thickness and initial GWL. The cone of water depression was observed during the tests, which indicates there are strong relationship between sinkhole and sinkhole occurrence. A novel peak-counting method was developed and validated to estimate spatiotemporal relations of the relations between GWLs and sinkhole collapse patterns.The field test was conducted at an active sinkhole site in Lake county, Florida to determine locations of points of breach and to monitor fluctuation GWL over time. Twenty piezometer sensors were installed, and the GWLs were monitored for three months at 30-min sampling rate. The daily moving average of GWL was calculated and visualized in ArcGIS map to understand spatiotemporal behavior of GWL at different locations from sinkhole positions. The monitoring results were compared with CPT, SPT and GPR results that were conducted prior to the piezo sensor installations. Strong correlations were observed between CPT, SPT, GPR and GWL results. From the results, it can be concluded that size and shape of the cone of water depression depend on dimensions of point discharges and properties of surrounding soil.

As Florida's population is expanding and greater fluctuations in groundwater levels are being recorded, Central Florida has been experiencing a higher frequency of sinkhole occurrences than ever before in recorded history. Sinkholes in Central Florida are formed by a combination of bedrock weathering and overburden soil erosion due to the groundwater recharge and are a part of Florida's past and future geology. The initial stage of a sinkhole is referred to as soil raveling and is the most effective time to perform soil improvement measures, such as grouting, to mitigate further expansion of a subterranean void. Subsurface exploration tests, commonly implemented by geotechnical engineers for site characterization, have been shown to detect these sinkhole anomalies even when no signs of subsidence are evident on the ground surface. Secondary geophysical testing has also been proven to detect sinkhole raveling anomalies, but at the expense of additional time and money added to the specific project. In this study, current practices in detecting premature sinkholes were expanded upon with a primary focus on Cone Penetrometer testing data (CPT). Cone Penetrometer tests provide valuable high-resolution quantitative information regarding the discrete strength characteristics of relatively loose sandy and clayey subsoil. CPTs are also much quicker and cleaner to perform when compared to other subsurface testing procedures (e.g. Standard penetration tests). Therefore, CPTs were chosen for this study to understand how they can be implemented to assess risk of future sinkhole collapse, or other karst construction concerns, in Central Florida specific soils. By implementing the findings presented in this report, Geotechnical engineers and contractors in central Florida will be able to practically evaluate the size and severity of potential forming sinkhole without the use of additional subsurface geophysical testing. The results of this study hope to eliminate extraneous testing costs, as well as maximize the efficiency of estimating mitigation products and procedures required all while still ensuring a safe design in Central Florida's highly karst areas.

For this thesis, a study was completed on two different structures on the UCF Orlando campus through the use of both structural plans and point cloud technology. The results sought to understand the viability of point cloud technology as an accurate tool for the static and dynamic modal analysis of existing structures. For static analysis, a portion of the framing of Spectrum Stadium was rendered, modeled, analyzed and compared to a previous case study. The results emphasized how different users can render dissimilar member sizes and lengths due to human judgment on point cloud visuals. The study also found that structural plans cannot always be relied upon as the most accurate source for analysis as the new point cloud produced more accurate results than the structural plans when compared to the control model. For the pedestrian bridge, the structure was scanned, rendered and modeled for both static and dynamic modal analysis. The point cloud produced from scanning the bridge was modified twice in order to have three distinct point clouds with varying densities: fine, medium and coarse. These three cases were compared to structural plans in a static analysis. The fine point cloud produced the most accurate displacement results with an accuracy above 96%. The data sources were also compared to experimental data under dynamic modal analysis to discover how lessening the density of point clouds affect the accuracy of results. The analysis showed that point cloud technology can give you an accuracy of 88% and above for frequency while also producing MAC values exceeding 0.9 consistently. Also, changes in density were found to change the accuracy of results but the numeric values stayed within close proximity by not differing more than 10%. This thesis shines a light on the accuracy point cloud technology can ascertain and the potential it has within engineering.

Denna studie undersöker marken under en tilltänkt nybyggnation av en lagerlokal. Denna mark är geotekniskt undersökt samt sättningsberäknad, den geotekniska undersökningen visade att markens jordprofil består av lera, siltig sand och fyllnadsmaterial. I denna studie har en parametrisk undersökning gjorts för att analysera hur olika materialparametrar i de olika jordlagren påverkar sättningarna, samt hur andra parametrar såsom vattennivå, tillskottspänningsmodell och laster påverkar sättningarna. Syftet är att undersöka vilka parametrar som påverkar sättningarna och varför de påverkar sättningarna. För att hitta de olika parametrar som påverkar har först en beräkning gjorts med de indata som fåtts inför uppbyggnationen, denna beräkning kommer i studien att benämnas som referensfallet. Sedan har detta beräkningsfall förenklats för att lättare kunna undersökas och jämföras, denna förenklade beräkning kommer benämnas som det förenklade referensfallet. I parameterstudien har en parameter ändrats i det förenklade referensfallet och sedan har detta resultat jämförts med referensfallet. Resultatet av detta har gett oss en tydlig bild över när och vilka parametrar som påverkar sättningarna. De parametrar som påverkar mängden sättning är först och främst mängden last samt kompressionsmodulen för de tre jordlagren, fyllnadsmassa, siltig sand och lera. Det resultat som presenteras har varit precis det man kan förvänta sig av en sättningsundersökning och resultatet påvisar även att beräkningsmodellerna som används ger en beräkning som är på den säkra sidan, vid jämförelse av de verkliga sättningarna.

Swedish transport administration initiated this Master Thesis project and the aim was to compare regulations for the design of high-speed railways from three European countries: France, Germany and Spain. The reason why this is of interest for the Swedish transport administration is the design of the first Swedish high-speed railway, called Ostlänken. Therefore, a literature study of the regulations and other literature regarding high-speed railway has been carried out. A basic description of railway components, slab track and ballasted tracks is presented. Ballasted embankments usually consist of a trackbed layer (ballast onto subballast), and the ultimate thickness of this layer is discussed, as there are a number of methods available to calculate the appropriate thickness, with a number of different design parameters. These design methods results in different trackbed thickness and choosing the “wrong” method might lead to an overestimation or underestimation of the trackbed layer. Constructing a ballastless railway line means that the ballast is replaced by another material, usually a slab made of reinforced concrete or asphalt, and the rail is cast onto this slab. Countries design their slab using different methods. Germany has constructed high-speed railway lines with a slab track solution, generally slabs with low flexible stiffness. France has until recently constructed their high-speed line ballasted but is now developing a new slab track technique, called NBT (New Ballastless Track) and Spain uses various methods. It is difficult to compare the regulations, however, there are some factors that at least begin to explain the differences between the countries: the frost hazard, the inherent ground quality, purpose with the railway (mixed traffic, solely passenger traffic, etc.), design parameters (life, axle load, etc.). Furthermore, the settlement requirements, soil classification and bearing capacity are factors that varies from country to country, but the origin for this variation is harder to detect.

At the Lampen site outside of Kalix, Sweden two embankments with heights 1,5m and 2m have been built to study and test the properties of sulfide soil that is located in the Gulf of Bothnia coastal areas. In this master thesis investigations have been done on what more could be done at the Lampen site today concerning new technics, measurements, observations and calculations etc. rather than building new embankments. Conclusions have been drawn from a total of 7 cases including Lampen what more could be done at the Lampen site. Verifications have also been done on the work made at the different cases. It was concluded that the work on all the different cases could be verified in some way against hand calculations or PLAXIS models beside the Murro test embankment site because this work had too little release data aterial given. Made verifications gave corresponding results to the described and measured ones in the real cases. Cases that have been looked at are: 􀀀 Murro test embankment (Karstunen et.al, 2005) 􀀀 Test embankment constructed to failure on soft marine clay in Malaysia (Brand, 1991) 􀀀 Test embankment on hydraulically placed PFA (Pulverized Fuel Ashes) in the United Kingdom (Cousens, et al., 2003) 􀀀 Trial Embankment on peat in Booneschans the Netherlands (Zwanenburg, et al., 2012) 􀀀 A case study on sulphide soil on road of E12 north link, Västerslätt, Umeå, Sweden (Törnqvist, 2013) 􀀀 Follow up and evaluation of settlements on the road 760 in Norrbotten, Sweden (Johansson, 2010) 􀀀 Test Embankments Lampen, Sweden (Andersson, 2012) From these cases it was concluded that more calculations in Plaxis 2D, Plaxis 3D and maybe Geosuite settlements software programs should be done at the Lampen site, both for long term and short term behavior and settlements as the only current model made is an Embacko V1.02 which is based on the work and results by Andersson (2012). Also verifications should be made by hand calculations on the models as this had not been done until today. Further disturbed samples should have been taken at the Lampen site as it have been done at the Murro site in Finland as this site is built on similar ground conditions with sulfide soil. Heavy equipment used at the site and as well the building of the embankments might have disturb or influenced the soil so the properties might have been changed. Also a couple of new measurement technics have been looked at for Lampen. The looked at technics are optics fibers, drones and ShapeAccelArray (SAA). ShapeAccelArray (SAA) devices could be installed at some different points on the site, down through the soil profile to give better readings on vibrations, accelerations, deformations and settlements. A drone could also be used during the snow free period to fly daily-predefined paths and make a 3D mapping of the geotechnical structures. And if the embankments would be built now again from the start it would be a good idea to install from the start a smart geotextile with polymer optical fibers (POF) totally covering the whole embankment size. This would give continues reading on deformations and displacements. But since the measurements and all other work at the Lampen site in the project went well and gave good results there is no need to do further changes.