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This thesis deals with the difference between two calculation programs for slope stability, namely Geoslope SLOPE/W and Novapoint GeoSuite Stability. The purpose of the thesis is to compare the two calculation programs with regard to the analysis of slope stability, as well as the two programs' handling of data. The two calculation programs use different Limit equilibrium methods to calculate safety factor and sliding surfaces for slopes. It can be expected that the result should be similar to one another, as well as the fact that both the calculation programs use different Limit equilibrium methods, but also when large differences in both safety factor and critical sliding surface give unreliable results. The thesis will also address the factors that may lie behind the fact that a possible stability failure should take place in a slope, as it gives an increased understanding of the analyzes that have been done. The work was carried out by modeling slopes with identical geometric relationships and identical material properties in the two calculation programs, a safety factor and a critical sliding surface for the slopes were developed for both programs and then compared with each other. / Föreliggande examensarbete behandlar skillnaden mellan två beräkningsprogram när det kommer till släntstabilitet, nämligen Geoslope SLOPE/W och Novapoint GeoSuite Stability. Syftet med examensarbetet är att jämföra de båda beräkningsprogrammen avseende vid undersökning av släntstabilitet, samt de två programmens hantering av data. De två beräkningsprogrammen använder sig av liknande Limit equilibrium-metoder för att beräkna säkerhetsfaktor samt glidytor för slänter. Man kan förvänta sig att resultatet bör vara varandra likt då dels att de både beräkningsprogrammen använder sig av liknande Limit equilibrium-metoder, men också då stora skillnader i både säkerhetsfaktor och kritisk glidyta ger opålitligt resultat. Examensarbetet kommer även ta upp de faktorer som kan ligga bakom att ett eventuellt brott ska ske i en slänt, då det ger ökad förståelse för de analyser som gjorts. Arbetet utfördes genom att slänter med identiska geometriska relationer samt identiska materialegenskaper modellerades i de båda beräkningsprogrammen, en säkerhetsfaktor samt kritisk glidyta för slänterna togs fram för båda programmen och jämfördes sedan med varandra.

The stability of natural slopes is goverened by many factors, one of which is the porewater pressure. In this study, a sensitivity analysis has been conducted in GeostudioSLOPE/W to investigate the impact of near-surface pore water pressure on thefactor of safety i silt slopes. The study includes five slopes along Ångermanälven,Sweden, which previously have been investigated within the framework of a slopefailure risk mapping of the area conducted by the Swedish Geotechnical Institute,SGI. The near-surface pore water pressure in the slopes has not successfullybeen measured in this area as the slopes are very high and steep. Calculations ofslope stability done previously by Tyréns instead assumed 1) that the pore waterpressure is zero 1m in from the slope face and 2) that it decreases hydrostatically(10 kPa/m) towards the slope face, and these are the parameters studied in thesensitivity analysis. When the pore water pressure is set to zero at the surface, thefactor of safety is reduced by an average of 7 %. Setting the pore water pressure tozero 2mfrom the surace increases the safety factor by 3%on average. A lower thanhydrostatic (7 kPa/m) pore pressure gradient increases the safety factor by on average2 %. A higher than hydrostatic pore water gradient decreases the safety factorby 16% on average. The results verifies that an increase in near-surface pore waterpressure gives a lower factor of safety and decrease in near-surface pore waterpressure leads to a higher factor of safety. The slopes are generally more sensitiveto destabilizing changes of the near-surface pore water pressure than of those stabilizing.Other factors such as vegetation, cohesion, dilatancy and erosion are notconsidered in this study but likely have a considerable effect on the stability. Whenmodelling the influence of near-surface pore water pressure and other parameters,it is recommended to use a FEM program.

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The devastating levee failures associated with hurricanes Katrina and Rita, and the more recent Midwest flooding, placed a spotlight on the importance of levees and our dependence on them to protect life and property. In response to levee failures associated with the hurricanes, Congress passed the Water Resources Development Act of 2007 which established a National Committee on Levee Safety. The committee was charged with developing recommendations for a National Levee Safety Program. The Secretary of the Army was charged with the establishment and maintenance of a National Levee Database. The National Levee Database is a critical tool in assessing and improving the safety of the nation's levees. However, the NLD data model, established in 2007, lacked a structure to store seepage and slope stability analyses – vital information for assessing the safety of a levee. In response, the Levee Analyst was developed in 2008 by Dr. Norm Jones and Jeffrey Handy. The Levee Analysis Data Model was designed to provide a central location, compatible with the National Levee Database, for storing large amounts of levee seepage and slope stability analytical data. The original Levee Analyst geoprocessing tools were created to assist users in populating, managing, and analyzing Levee Analyst geodatabase data. In an effort to enhance the Levee Analyst and provide greater accessibility to levee data, this research expanded the Levee Analyst to include modifications to the data model and additional geoprocessing tools that archive GeoStudio SEEP/W and SLOPE/W simulations as well as export the entire Levee Analyst database to Google Earth. Case studies were performed to demonstrate the new geoprocessing tools' capabilities and the compatibility between the National Levee Database and the Levee Analyst database. A number of levee breaches were simulated to prototype the enhancement of the Levee Analyst to include additional feature classes, tables, and geoprocessing tools. This enhancement would allow Levee Analyst to manage, edit, and export two-dimensional levee breach scenarios.