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A case study on the role of blast vibration on the 1996 Finneidfjord landslide was carried out. This catastrophic landslide which claimed four lives has been under investigation during the past decade. The study area has been developed as natural laboratory and different field and lab investigation have been carried out in the process of understanding the event bed. The mechanically weak layer that the landslide used as a slip surface is found 2.8-3.1m below the sea bed and is composed of loose sand layer sandwiched between two very low permeable clay layers. The main focus herein is the effect that the vibration had on the sand layer and see if the energy from it was able to generate an excess pore water pressure or even liquefaction.Literature review on different models for calculating energy from vibration and liquefaction susceptibility is done. The energy calculation models require inputs that involve laboratory test therefore they are to be referred for the future work. As for the liquefaction susceptibility; data from the field and laboratory investigation are utilized and are used for the simple liquefaction susceptibility analysis.Utilizing a FEM software QUAKE/W, part of the GeoStudio software suite, the amount of excess pore water pressure generated due to the dynamic loading from the blast is analyzed. Keeping the parameters of the other materials in the model constant and changing the damping ratio of the sand layer ranging from 1% to 33%, and by changing the geometry of the model an excess PWP in the range of 0.4KPa to 6KPa is obtained. As for the liquefaction susceptibility analysis using the cyclic stress ratio, a factor of safety of 2.3 was obtained leading to the conclusion that liquefaction was not the cause of the landslide. With the excess PWP obtained from the dynamic analysis plus a reading from a piezometer installed close to the slide scar, slope stability analysis is done with a software tool called SLOPE/W which again is part of the GeoStudio software suite. The initial stability condition of the slope, only considering the excess PWP from the piezometer reading, was on the verge of failure. The analysis carried out, considering the result from the dynamic analysis, gave a factor of safety less than one. Based on the results one might conclude that the excess PWP caused the landslide but given the fact that some very important parameters which should be obtained from a lab investigation are lacking, the study can only show that there is a possibility for generation of an excess PWP and for a slope already on the verge of failure, reduction in the effective stress caused by the excess PWP could lead an incidence like in Finneidfjord. Future work for improving the study and some recommendations that could help in dissipating excess pore pressure in such a condition are also forwarded.

Dette prosjektet tar for seg effekter av peleramming i sand. Fokuset i oppgaven er effektene av vibrasjonene og eventuelle komprimeringer de medfører. Studiet har hatt størst fokus på selve vibrasjonene og i noe mindre grad hvordan vibrasjonene oppstår og hvor store de eventuelt blir som følge av ramming av peler. Prosjektet er et forprosjekt for å kartlegge utbredelsen av problemet, sammenfatte aktuelle teori samt planlegge og utføre forsøk i sand for å se på effekter av peleramming i sand.I studiet er det planlagt tre forsøk, hvor to ble utført. Forsøkene dreide seg blant annet om å måle effekter i overflaten når en pel rammes og forsøke å finne en sammenheng mellom vibrasjonsnivå og komprimering i sand. Forsøkene ble utført med varierende vanninnhold og helt tørr sand. De aktuelle forsøkene viste seg å gi fornuftige resultater. Videre i prosjektet er det samlet sammen og studert noen tilfeller hvor det har oppstått skader i nærliggende konstruksjoner, antagelig som følge av komprimering i sanden.Resultatene av prosjektet viser flere spennende aspekter vedrørende problemstillingen. Likevel stilles det spørsmål ved utbredelsen av den, da det viste seg at slike tilfeller ikke forekommer så ofte.

A MATLAB Finite Element code for plane strain analysis of footings on an Elasto-plastic material using the Mohr Coulomb failure criteria has been developed. The first step is to develop codes for mesh generation and Gaussian numerical integration. Next, the force matrix, the stiffness matrix and the self weight matrix are assembled. After that functions for non linear analysis such as the plastic potential derivatives are formed. Finally plots of the mesh, displacement shadings, stress shadings and stress-strain curves are developed. For the purpose of verification results from the code for biaxial test are compared with the theoretical solution. Additionally comparison is made between the code and prandtl’s bearing capacity solutions for a footing problem. These results show that accuracy depends on two factors: - the type of the element and the number of elements used. The three node triangular element and the four node rectangular element give less accurate results when compared to higher order element types. And for a relatively accurate result the number of elements should be too high.

Abstract:Nowadays, the offshore is very extensive and of great economic value for gross development. Typically all kinds of offshore structure will experience storm loading and need to consider the influence of cyclic loading. When cyclic loading is applied, the soil failure mechanism and strength of soil should be changed, which means the cyclic analysis need to perform in the way different from static analysis. If designer ignore the effect of cyclic load, the failure or large plastic deformation will occur with increasing the number of cyclic loading. I have studied the lateral displacement of conductor under influence of cyclic loading, and the numble of cyclic loading is 10, 100, 1000 and 10000 in the calculation, respectively. Moreover the soil modulus will be calculated from Matlab with the elastic pile theory (Lars Grande, Phd thesis 1976). During the cyclic loading, the soil degradation should be considered, therefore, the modified P-y curve for influence of cyclic loading is included which describes the change of soil. In terms of calculation, there are two types of BOP, 450 tons and 250 tons, meanwhile the horizontal cyclic loading equal to 2000 kN which is performed on BOP.Then the natural frequency analysis is performed in last chapter. The natural frequencies of the conductor, BOP, wellhead and soil system have a significant influence on the system stability. The frequencies that correspond to the maxima magnification factor M which means the vibration could be magnified. Without the damping impact, when a frequency of cyclic loads equal to the natural frequencies of the system, the magnification factor will be infinite, while the damping is included, the factor will also meet a peak value when the two kinds of frequencies meet each other. Consequently the analysis will be operated for both two types BOP in this calculation. And The multiple-degree-of freedom model is operated in this case, therefore, the conductor is considered as an elastic pile which is divided into several elements and that conductor only connect soil with springs is included in this chapter.Further work in connection to soil plasticity theory, can be developing more accuracy deflection calculation. When cyclic loading is considered, the plastic zone is developing around conductor, therefore the new soil model need to use for practical project.

The monopiles with typical diameters of 4-6m are mostly used as foundations for the offshore wind turbine structures to resist the vertical and horizontal loads. The response of the laterally loaded pile depends upon the soil and pile behavior and also on the interaction between them. Various methods for the development of p-y curves exist and the accuracy of such methods depends upon the data from which it was developed. The accuracy of the analysis of the pile depends on the accuracy at which the p-y curve represents the soil response to the lateral pile deflection because most of the commonly used p-y curve criteria are based on a very limited number of tests. The p-y curve recommended by American Petroleum Institute (API) code which is widely used by geotechnical engineers for the analysis of laterally loaded piles; however the method was developed for the slender piles with diameters up to approximately 2m. Hence several authors have claimed that p-y curves should be revised to be applicable for large diameter rigid pile (Augustesen, Sorensen, & Ibsen, 2010), (Achmus, Abdel-Rahman, & Kuo, 2008).The thesis presents the finite element model (FEM) analysis of monopiles in marine clay with the diameter from 1m to 6m by means of the Plaxis 3D Foundation. To avoid the influence of the pile flexibility and pile rotation, lateral translation of rigid piles is analyzed.The rigid pile and soil with hardening soil parameter is modeled in FEM Plaxis 3D Foundation. Piles are loaded with lateral loads to obtain the soil response on pile and pile deflection at different stages which in turn is used for the development of p-y curve and are compared with the API p-y curves. The result does not show any diameter effect in the initial stiffness but the initial stiffness of soil is very low in comparison to that given by the p-y curve (API code). Low stiffness compared to API p-y curve may be due to the selected parameters of the soil model.As the result shows difference in p-y curve from FEM 3D plaxis foundation and API code, some field test results for larger diameter will be fruitful to decide which method is valid for the analysis of the larger diameter monopiles.

Mange norske veger er svært utsatt for snøskred, og Statens vegvesen jobber kontinuerlig med å utvikle effektive tiltak for sikring mot snøskred. Denne oppgaven har som hensikt å vurdere sikringstiltak sikringseffekt mot snøskred. Vurderingene vil også innebære undersøkelse av faktorer som kan påvirke sikringseffekten negativt. 14 sikringstiltak ble vurdert langs fire vegstrekninger i Møre og Romsdal og Sogn og Fjordane. Tiltakene bestod både av diverse overbygg og terrengtiltak med god spredning i alder. Undersøkelsene viste at en del av de eldre tiltakene var underdimensjonerte i forhold til skredene. Ledevollene var da for lave og korte, slik at skredene kunne gå over. Overbyggene var også for korte i lengden, slik at lagringsplassen ble for liten. Mange av terrengtiltakene, samt noen av overbyggene, hadde også behov for vedlikehold og reparering av skader. Beregnignene av sikringseffekten viste at de yngre tiltakene hadde svært god effekt. Det antas at årsaken er at utviklingen av effektive metoder for sikring har kommet langt. De yngre tiltakene er da ofte bedre tilpasset skredterreng og frekvens. Effekten ved bruk av rassikringsplanen var noe vanskelig å måle, men de fleste tiltakene så ut til å være bygd slik rassikringsplanen foreslo.

This thesis consists of 8 chapters and each chapter is described as follows:Chapter 2: Presents the different types of piles which exist today and their classification.Chapter 3: Presents the different soil parameters we use in pile analyses and design and the properties of these parameters.Chapter 4: Presents the different empirical and theoretical static pile capacity equation. It also presents the effect of time and plugging on pile capacity.Chapter 5: Presents pile dynamics, static and dynamic load tests on piles.Chapter 6: Presents a case study which is a case of a bridge project on the Drammen selva river in Drammen, Norway.Chapter 7: Presents the analysis and results obtained for the case study described in chapter 6.Chapter 8: It is the last part of the work which presents conclusions and possible future work.

SummaryThis study is aimed at the parametric study of EPS as a light weight fill embankment in road construction. Both short and long term deformation characteristics as well as mechanical parameters of EPS are discussed based on laboratory test outcomes and literature reviews.Literature reviews on EPS material shows scatter of results mainly on mechanical parameters. Inconsistent laboratory testing procedures, specimen variation and interpretation of results are mentioned as a reason for the cause of parameter variation.To evaluate the parameters of EPS, two basic tests have been used in this study- short term loading tests as well as long term loading tests. Short term loading tests are carried out to evaluate the compressive strength and the stiffness parameters of EPS under different specimens and testing procedures. Meanwhile long term loading of EPS is analyzed based on total deformation results obtained under 30KPa constant loading of the specimens for 5 consecutive days. In this study, three different sized (50mm, 100mm and 150mm) cubic samples, three different shaped ( cubic, cylinder and disc) samples, three different loading rates (5mm/min, 3mm/min and 1mm/min) and four specimen temperatures (-20, -10, -5 and 20oC) are used to investigate parameters of EPS. Results suggest that stiffness of the polymer increases as sample size increases and the same response in increase of stiffness and compressive strength is showed when disc shaped samples, small loading rates and low specimen temperatures are used in general.The long term deformation test on EPS for the same set of specimen variation is repeated. Results confirmed the decrease in creep and total deformation when sample sizes increases. Creep test results on small samples tend to overestimate the total deformation as compared to full scale projects. In addition, disc shaped samples rather give less immediate deformation, however, deformation rate is high enough to give an overestimate along the time scale. Further, a temperature decrease on specimens brought an expected increase in creep.Finite element simulation of EPS geofoam are evaluated using hardening and soft soil models in PLAXIS 2D. EPS parameters calibrated using HS-model gives a practical fit compared with laboratory results and similar trends in long term deformation of EPS embankments are achieved using SSC model in PLAXIS 2D. A slight tendency of overestimation in stiffness is shown when soil models are used.Study regarding creep modeling of EPS embankments is discussed in later stages. Empirical equations (Findley equation), equations using isochronous stress-strain curves, sherby-dorn plots and mechanical creep models are studied. Equations developed using creep test results obtained by full scale laboratory test on EPS embankment is used for further discussion. Practical estimation of total deformation was possible up on results found.Several conclusions are made up on this study: EPS is not nearly uniform when it comes to mechanical parameter due to its production process, a value of E=5MPa and v=0.1 is advised to be used for embankment design. EPS parameter calibration using HS model gives practically applicable result. Moreover, the total deformation in EPS under a constant compressive load of 50%*compressive strength is less than 2% for its entire design time.

Sensitive clay landslides especially that of quick clay are the major natural hazards in Canada and Scandinavian countries. Fair estimation of post-failure movement (retrogression and run-out distances) is very important in taking remedial measures like hazard mapping and mitigation strategies to protect loss of human lives and properties as well as damage of infrastructures. To do these estimations, some empirical approaches have been used so far. However most fell short to give close prediction of the run-out distances. This situation gives rise to implement some of the existing mass flow numerical modeling tools to simulate post-failure movements of sensitive clays. Some preliminary studies were conducted to evaluate the extent to which the available flow (rheological) models are able to simulate run-out of sensitive clay slides.This study continued the search and found the Voellmy rheological model implemented in RAMMS::Debris Flow and DAN3D. The model is tested by back calculating a small scale run-out laboratory model test and the 2012 Byneset, Norway, quick clay landslide cases. Preliminary attempt to numerically simulate quickness test of sensitive clays was also made.Even though the same rheological model is implemented in RAMMS and DAN3D, some differences in the analysis results were observed. This rheological model was able to simulate the run-out distances of the given cases. However, its two governing friction parameters are found more sensitive to the flow conditions than the usual strength parameters of sensitive clays.Some recommendations and future works are also given depending on the simulation results.