In this study the breakage mechanics of brittle glass marbles was investigated. The pro-cess was to firstly investigate them in laboratory environment. The marbles or specimens was loaded until a crushing breakage occurred in a single point load test called Single Sphere Point load test in this document. From the test we could derive the crushing load, the deformation and strain, the tensile strength and other parameters needed for the second part of this work. Namely the numerical modelling, here we investigated the specimen with the Discrete Element method or DEM for shorts. The software used was an open sourced software created in MATLAB called DICE2D. Since the software was developed to only include the mathematical part of the numerical model several re-coding processes were needed, with other words the creation of add-ons to the software. The add-ons were automatic code created in Python where the user now are able to create a geometrical model for the specimen that the software can interpret. There were two add-ons created in order to generate a geometry, called the circumference method and the random generation method, i.e. different methods of creating a geometry. The first method, the circumference method creates circumferences filled with smaller particles with the same radii, then moves a step inward to the specimens center and fills another circumference until the center is reached. The second method, the random method generates particles positioned randomly inside the specimen with a random radii, created such that the radius of the particles is chosen with an interval, were the user can choose the smallest and the largest particle radius. It was found that both these add-ons were of great use with different purposes in mind. The circumference method was able to create a brittle material where the deformations were low. The random method also created a brittle material but since the particles were randomly positioned there also was empty space created such that the deformations were larger than the one found in the laboratory environment, since the empty space between the particles was closed before the plastic deformation could occur. Hence the second method of generation is more relevant for concrete and rock mechanics since in these cases this is the actual process, where the micro-cracks first closes then the elastic and plastic deformation occurs [Martin, 1993]. The first method, the circumference method is of great use when investigating the elastic deformations since here the particles are in contact. Thus creating the scenario for granular particles, In this thesis however the circumference method was used in order to create a solid specimen. For future use this add-on should be used in order such that each particle simulates an actual grain. The results found with both of these methods follows the results found in the laboratory test for the crushing load. But the incremental increase of force when the load is applied on the specimen was not able to be simulated. It is believed that the software is having difficulties to simulate brittle material due to the small deformations and the large loads.

This research involves shake table testing of 1g scale models that mimic the coupled seismic response of a structure on a shallow mat foundation and foundation soil (known as soil-foundation-structural-interaction or SFSI). In previous research, SFSI effects have been quantified through analytical models, numerical analyses, and limited field data. This research works towards increasing the amount of empirical data through scale model shake table testing. A suite of earthquake time histories is considered in evaluating a nominal 10th scale soil-structure model using a flexible wall barrel on a 1-D shake table. San Francisco Young Bay Mud (YBM) is used as the prototype soil and long period narrow building as the prototype structure. Foundation embedment depth, fundamental mode of the structure, and seismic loading function are varied to generate a large database of SFSI results under controlled conditions. The foundation level response is compared to free-field responses to determine the magnitude of the SFSI. The results confirm the effects of foundation embedment on the peak ground motion and the spectral acceleration at the predominant period of the structure. The foundation level accelerations are deamplified compared to free-field results. Results also confirm the legitimacy of the testing platform and program by comparing the data to previous experimental study.

A nonlinear Mohr-Coulomb constitutive model with a strain dependent yield surface and non-associated flow was employed to study the plastic soil properties which affect the rate of surface fault rupture propagation in reverse events. These numerical simulations show a trend for soils with higher stiffness to have a higher rate of rupture propagation. Additionally the study shows the effects of strain softening and hardening on the rate of rupture propagation. Soils which strain harden exhibiting ductile behavior typically require more basal offset to rupture to the surface than soils which strain soften exhibiting brittle behavior. These results agree with our previous fault box studies, which showed that soils with higher near surface shear wave velocity were more likely to propagate rupture to the surface for a given reverse event. The numerical modeling allowed for a more comprehensive evaluation of material types and fault angles than the fault box, and provided confidence in these findings.

Integral bridges are designed without expansion joints or bearings to eliminate the maintenance and repair costs associated with them. Thus, the expansion and contraction due to daily and seasonal temperature variations of the deck of the bridge are restricted by the abutments, causing the abutments to move cyclically towards and away from the granular material used as backfill. This movement results in a stress accumulation in the backfill retained by the abutments. The Discrete Element Method (DEM) was used was used to perform a numerical sensitivity analysis, investigating the effect of granular particle shape on the response of backfill material retained by integral bridge abutments.   Two DEM software suites were used to perform the simulations, namely STAR-CCM+, a commercial code, and Blaze-DEM, a research code under development at the University of Pretoria. Blaze-DEM makes use of Graphics Processing Unit (GPU) computing as opposed to traditional Central Processing Unit (CPU) computing. Blaze-DEM delivered computational times over 150 times faster than the equivalent simulation in STAR-CCM+. The results from the numerical sensitivity analysis showed that the particles with lower sphericities (higher angularities) experienced larger accumulations of stresses on the abutment as opposed to the more spherical particles. This was suggested to be a result of particle interlocking and reorientation. / Dissertation (MEng)--University of Pretoria, 2018. / Civil Engineering / MEng / Unrestricted

Different rock formations may appear within the same mass, or even within the same formation there may exist layers of different materials, creating interfaces between layers (an interface may be defined, in more general terms, as a frictional contact that separates two similar or dissimilar materials). Currently, there is no well-established experimental work that investigates the influence of frictional interfaces, interface orientation and flaw geometries on crack behavior (i.e. initiation, propagation and coalescence) in brittle specimens under compressive loading. A series of experiments on homogeneous gypsum specimens, used as a rock-model material, containing two pre-existing open flaws and a frictional interface has been performed under uniaxial compression. The experiments investigate how cracks interact with interfaces and how different variables (i.e. flaw geometry, interface inclination angle and interface roughness) affect crack behavior in homogeneous materials separated by an interface. The specimens are 203.2mm high, 101.6mm wide, and 25.4mm thick. The two flaws, with 0.1mm aperture and 12.7mm length (2a), are created through the thickness of the specimen. The spacing (S) between flaws, continuity (C), and inclination angle, measured from the horizontal, (β) define the geometry of the flaws. Three flaw geometries are tested: S=0, C= -2a= -12.7mm, β= 30° (i.e. a left-stepping geometry); S= 2a= 12.7 mm, C=a=6.35 mm, β= 30° (i.e. an overlapping geometry) and S= 3a= 19.05mm, C=0, β= 30° (i.e. a right-stepping geometry). Smooth and rough unbonded interfaces are created by casting the specimen in two parts. The first half of the specimen is cast against a PVC block with an inclined face (i.e. 90°, 80° or 70°) with respect to the vertical axis of the specimen. The second half is then cast against the first one. Sandpaper may be attached to the PVC block to provide different roughness to the interface; a debonding agent applied to the interface ensures a cohesionless contact. In the experiments, digital image correlation (DIC) is used to monitor crack propagation on the specimen surface. The experiments indicate that the interface itself is an important contributor to new cracks and its presence in the specimens reduce crack initiation stress. Furthermore, the increase in roughness and inclination of the interface (i.e. from horizontal to 70° from the vertical) causes crack initiation stress to decrease. It was also observed that the angle between the incident crack plane and the interface affects whether an incident crack will penetrate an interface or be arrested: Tensile cracks that meet the interface at 30° to 60° angle get arrested, while those at or above 70° cross the interface with an offset of 0 – 1.2 mm. While shear cracks that meet the interface at 20° to 63° angles get arrested at the interface, while those at or above 70° cross the interface with an offset in the range of 0 – 1.76 mm. Another relevant finding is the fact that changes in interface roughness or inclination angle did not affect the angles at which cracks initiate or reinitiate at the interface.<div>A numerical study was conducted using the Extended Finite Element Method (XFEM) capability in ABAQUS, to further investigate the fracture behavior observed in the experiments and, more specifically, the influence of the different types of interfaces. An extensive investigation of the stress fields around the tips of the flaws and of the new cracks, as well as along the interface in the specimens, was conducted to determine the relationship between stresses and crack initiation and propagation (i.e. type and direction of cracks). The stress-based approach yields predictions of tensile and shear cracks location and initiation direction that are in good agreement with experimental results. The numerical investigation indicated that rougher horizontal interfaces induced slightly higher tensile stresses around the interior and exterior flaw tips than smoother interfaces, which may explain why tensile cracks at these locations initiated earlier in specimens with a rough interface. Moreover, inclined interfaces induced higher tensile stresses around the interior and exterior flaw tips than horizontal interfaces, which may justify that, in the experiments, inclined interfaces promoted crack initiation earlier than horizontal interfaces.</div>

<div>This research consists of the development of a new educational tool for calculations of 2D slope stability problems, named PNW-SLOPE. Slope stability has been considered one of the most important topics in geotechnical engineering for many years, so this is a subject which students should build a good background in the university. This program was created in Microsoft Excel with the aid of VBA (Visual Basic for Applications). The use of VBA allowed the creation of a good user interface, therefore those who are using the program can easily follow the instructions to create, analyze the model and check the results. Even though there are many commercial programs with the same application, this research presents a new alternative, more focused on educational purposes. PNW-SLOPE is divided in several modules.The first consists of the geometry definition of the slope. The second module consists of a deterministic slope stability analysis considering limit equilibrium method and the method of slices. The third module consists of a probability analysis considering Monte Carlo simulation. With these two options, users can compare both analysis and understand how important is the consideration of probability analysis in Geotechnical Engineering. This is a pertinent topic nowadays, since reliability analysis is increasingly being incorporated in standards and design codes throughout the world. An additional module was created for rock slope stability problems in which the failure results from sliding on a single planar surface dipping into the excavation. Several examples are presented to demonstrate some of the features of PNW-SLOPE and results are verified with commercial programs such as Geostudio Slope/w and Rocscience Slide 2018.</div>

Studien syftar till att undersöka hur fastighetsgränser markerats ur ett historiskt perspektiv. Detta är en kunskap som är nödvändig då en mätingenjör gör utsökning av gränsmarkeringar i fält och gränsutvisning av fastighetsgräns.Studien syftar även till att belysa de svårigheter mätingenjörer kan möta vid gränsutvisning samt hur arbetet bör planeras. Arbetet är avgränsat till att endast gälla fyra fastigheter i ett utvalt område i Värmland. Genom inmätning och gränsutvisning av gränsmarkeringar med GNSS mottagare och nätverks-RTK där resultatet sedan jämfördes med motsvarande gränsmarkeringar iregisterkartan. I studien ingår även en litteraturöversikt över fastigheters tillkomst genom historien och fastighetsreformer samt fastighetsbildningsåtgärder, detta för att ge en förståelse för fastighetsgränsers uppkomst och dess betydelse för gränsmarkeringar. En översikt över fastighetsgränser, hur de markerats och hävdas. Fallstudien belyser mätingenjörens arbetsgång vid gränsutvisning. Arbetsgången innehåller arkivutredning, gränsutsökning och gränsgång. Arkivutredningen av de fyra fastigheterna visar gränser från storskifte och laga skifte samt fastighetsbildningsåtgärder som hemmansklyvning, avsöndring och ägostyckning. Vid gränsutvisning och gränsutsökning återfanns 31 änd- och brytpunkter längsde olika fastighetsgränserna. De markeringstyper som återfanns var 15 råstenaroch åtta rör i mark övriga var gränshävd.Medelvärde på den beräknade radiella avvikelsen i tätort i fallstudien är 0,17 meter medan avvikelsen på landsbygd är mellan 5,27 och 4,03 meter. Slutsatsenav fallstudien är att registerkartans avvikelser inom studieområde har ett medelvärde på runt fem meter och att skillnaderna är stora. / The study aims to investigate the knowledge a surveyor needs before border expulsion. The study contains a literature review addressing how property boundary are marked from a historical perspective. The aim is to highlight the difficulties that the surveyor may encounter working with border expulsion. This study is limited to four properties in one selected area in Värmland. The problem this study addressing is relevant because this service has been excluded from Lantmäteriet that oversees the cadastre system in Sweden. The result is a gap that need to be meet when many property owners are unsure of their property boundaries. By measuring and delineating boundary markings with GNSS receivers and network RTK where the result was then compared with corresponding boundary markings in the register map. The study also provides a literature review to give an understanding of the origin of property boundaries and their importance for property boundary. An overview of property boundaries, how they are marked and maintained. The case study sheds light on the surveyor's work process at border expulsion. The workflow includes among other archive investigation and border search. At border expulsion and border search, 31 end- and break points were found along the selected property boundaries. The mean value of the calculated radial deviation in urban areas in the case study was 0.17 meters, while in the countryside the mean value of the calculated radial deviation was between 5.27 and 4.03 meters. The study shows that the register map in this area in Värmland has an average of deviations of around five meters.

Traditionellt är avvägning den metod som används vid höjdsättning av nyetablerade stompunkter. Men det är en teknik som kan vara både kostsam och tidskrävande, i synnerhet då avståndet till närmsta anslutningsnät är ansenligt. Den här studien undersöker en alternativ metod till avvägning, RUFRIS-metoden. RUFRIS (RealtidsUppdaterad FRI Station) bygger på att totalstationen erhåller sin position genom avstånds- och vinkelmätning kombinerat med GNSS-teknik i realtid. Det är möjligt då mätstången är försedd med både prisma och GNSS-rover, vilket gör att totalstationen beräknar sina positionskoordinater direkt i fält. Mätosäkerheten i plan är låg och metoden används regelbundet, men vid höjdmätning används fortfarande avvägningsteknik. Syftet med uppsatsen är att undersöka RUFRIS-metodens mätosäkerhet i höjd, samt dess pålitlighet som alternativt tillvägagångsätt vid höjdbestämning av nyetablerade stompunkter.  I studien samlades data in från mätningar på tre olika områden i Karlstads kommun med nära anslutning till en känd stompunkt med koordinater i korrekt referenssystem, SWEREF 99 13 30 samt RH2000. Totalt genomfördes 60 totalstationsetableringar med RUFRIS-metoden, 20 på respektive studieområde. 10 med 6 bakåtobjekt och 10 med 15 bakåtobjekt med efterföljande inmätning av respektive stompunktshöjd som jämförelsereferens. Utifrån insamlade mätdata sammanställdes och beräknades medelhöjd, mätosäkerhet och spridning inom mätserierna för varje studieområde.  Studien visar att höjdbestämning med RUFRIS-metoden kan uppnå standard-osäkerhet på 2,5 mm vid enskild mätning då 15 bakåtobjekt nyttjas. Som högst blev standardosäkerheten för enskild mätning 5,4 mm, utfört med etablering med 6 bakåtobjekt. Vid jämförelsen med Karlstads kommuns stompunkter blev samtliga höjder lägre än motsvarande avvägd referenshöjd. Resultatet tyder på ett systematiskt fel där GNSS/RTK-mätta höjder redovisade lägre nivå än de avvägda stom-punkternas höjdkoordinater. Att detta tolkas som systematiskt fel baseras på den samlade spridningen inom varje mätserie. Som mest blev den 16,2 mm, vid etablering med 6 bakåtobjekt, vilket tyder på stabila etableringar med goda mätresultat. Minst spridning inom en mätserie blev 7,1 mm då 15 bakåtobjekt användes för etablering.  Utifrån resultatet kan slutsats dras att höjdbestämning med RUFRIS-metoden kan vara ett alternativ till traditionell avvägning då krav på mätosäkerhet ställs till 10 mm. Vid goda förhållanden för GNSS/RTK-mätning och med 15 inmätta bakåtobjekt kan mätosäkerhet på 5 mm i höjd anses rimligt att uppnå med RUFRIS-metoden. Då krav på lägre mätosäkerhet ställs bedöms avvägning som mer tillförlitligt, men då bör avståndet till närmaste höjdfix vara en faktor att ta med i beaktning. / The traditional method of determining vertical coordinates in surveying is by levelling. The height from a definite coordinate point gets transferred to a new point. But what if there is no point nearby? Levelling over long distances is costly and time consuming. This study is investigating another way of setting new height points, the RUFRIS-method. The RUFRIS-method is a Swedish innovation and stands for “Realtime Updated Free Station” (RealtidsUppdaterad FRI Station in Swedish language). Establishments of the total station with the RUFRIS-method is done in real time and the total station gets its coordinates by a combination of traditional measurements by distance and angle combined with GNSS-technique. This is possible due to a multiple pole with both a reflector and a GNSS-rover set on top. The purpose of this study is to investigate the precision of height levelling with the RUFRIS-method and if the method could be used as a substitute to traditional levelling.  In this study three separate areas in Karlstad were selected and set up for RUFRIS-establishments. On each area there was a point with known coordinates in the correct reference system, SWEREF 99 13 30 and RH2000. A total of 60 RUFRIS-establishments were set up, 20 on each area. 10 with 6 backsight points and 10 with 15 backsight points, including subsequent measurement of the control points as a comparison reference. Based on the collected measurement data mean height, uncertainty and spread within the measurement series were analysed and calculated.  The result in this study shows that the lowest uncertainty achieved during single measurements was 2.5 mm in one of the RUFRIS-establishment series with 15 backsight points. Highest uncertainty was 5.4 mm during RUFRIS-establishment with 6 backsight points. Comparing with the known vertical coordinates the result indicated a systematic error due to the fact that every measured height ended up lower than the references height. The conclusion that a systematic error occurred were made on the basis of the narrow spread within all the measured series, 7.1-16.2 mm. The result indicates that all the establishments with the RUFRIS-method were solid and trustfully made.  The conclusion of this study is that the RUFRIS-method is a useful and solid way to determine new height points in cases were the uncertainty-limit is set to 10 mm. Under good GNSS/RTK conditions and establishment made with 15 backsight points its likely to expect uncertainty of 5 mm in height level with the RUFRIS-method. When requirement for lower uncertainty is demand levelling is considered as more reliable, but the distance to the closest known coordinate-point should be a factor to be considered.

The population in Sweden and around the world is increasing. When population increases, cities become more densely populated and a demand for investments in housing and infrastructure is created. The investments needed are usually large in size and the projects resulting from the investments are often of a complex nature. A major factor responsible for creating the complexity of the projects is the lack of space due to the dense population. The lack of space creates a situation where a very common feature of these types of projects is the use of earth retaining systems. The design of retaining systems in Europe is performed today based on Eurocode. Eurocode is a newly introduced standard for the design of structures and is developed in order to make it easier to work cross borders by using the same principle of design in all countries. For the design of retaining walls in Sweden, Eurocode uses the old standard as the basis of the design procedure consisting of two separate calculations, ultimate limit state and serviceability limit state. Since soil does not consist of two separate mechanisms consisting of failure and serviceability, this approach to solving engineering problems fails to address the real behavior of soils. To handle this problem Bolton et. al. (1990a, 1990b, 2004, 2006, 2008, 2010) developed the theory of “mobilized strength design” where a single calculation procedure incorporates both the calculation of deformations and the safety against failure. The calculation uses conservation of energy and the degree of mobilized shear strength to study deformations in and around the retaining system and the safety against failure in mobilizing the maximum shear strength of the soil. The aim of this thesis was to introduce the theory of mobilized strength design to geotechnical engineers in Sweden working both in academia and in industry. Another aim of the thesis was to develop a tool that could be used to perform calculations of earth retaining systems based on this theory. The development of a working tool has resulted in a Matlab code which can in a simple way be used to calculate both deformations in the retaining system and the safety against failure by using the degree of mobilized shear strength presented in the theory. The Matlab code can handle ground layering with different shear strengths and weights of the soil. A comparison instrument in a Mathcad calculation sheet have been developed to produce results based on the original theory where the feature of soil layering is not incorporated into the calculation procedure. The thesis shows that the Matlab code developed performs well but is not yet sensitive enough to produce the same results as the Mathcad calculation sheet and needs to be further developed to make it more robust in order to handle all different excavation scenarios. v The theory of mobilized strength design has been introduced to geotechnical engineers in Sweden and the thesis studies the theory and shows the calculation procedure and how the different input values and calculations affect the analysis. The thesis also shows some areas in which the theory and the code can be modified and where further research can be performed in order to make them fully applicable to Swedish conditions. As an example the use of rock dowels drilled into the bedrock and attached to the retaining structure is a common feature for deep excavations in Sweden. Further research can be pursued on how to incorporate the energy stored in the rock dowels into the calculation procedure.

Joints are the main features encountered in rock and sliding of rock blocks on joints is classified as the principal source of instability in underground excavations. In this regard, joints’ peak shear strength is the controlling parameter. However, given the difficulty in estimating it, shear tests are often performed. These are often quite expensive and also time consuming and, therefore, it would be valuable if shear tests could be artificially performed using numerical models. The objective of this study is to prove the possibility to perform virtual numerical shear tests in a PCF2D environment that resemble the laboratory ones. A numerical model of a granite rock joint has been created by means of a calibration process. Both the intact rock microparameters and the smooth joint scale have been calibrated against macroparameters derived from shear tests performed in laboratory. A new parameter, the length ratio, is introduced which takes into account the effective length of the smooth joint compared to the theoretical one. The normal and shear stiffnesses, the cohesion and the tensile force ought to be scaled against the length ratio. Four simple regular joint profiles have been tested in the PFC2D environment. The analysis shows good results both from a qualitative and from a quantitative point of view. The difference in peak shear strength with respect to the one computed with Patton´s formula is in the order of 1% which indicates a good accuracy of the model. In addition, four profiles of one real rough mated joint have been tested. From the scanned surface data, a two-dimensional profile has been extracted with four different resolutions. In this case, however, interlocking of particles along the smooth joint occurs, giving rise to an unrealistic distribution of normal and shear forces. A possible explanation to the problem is discussed based on recent developments in the study of numerical shear tests with PFC2D.