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When the excess pore water pressure generated during an earthquake dissipates in saturated loose sand, it causes post-liquefaction reconsolidation that can potentially yield substantial damage to the structure. To build resilient infrastructure, it is paramount to estimate these settlements as well as introduce soil reinforcement techniques to mitigate associated risks. Although there are abundant studies on liquefaction triggering assessment, the study of post-liquefaction settlement and the effects of stone columns as soil reinforcement is a relatively less established field. Generally, simplified empirical methods are employed for settlement evaluations. However, they possess several limitations such as the influence of non-liquefiable layers, soil fabric, permeability, and so on. Numerical models can be utilized to capture these effects with proper validation. This study evaluates the performance of stone columns in reducing seismically induced post-liquefaction settlement utilizing the Finite Element Method (FEM) and constitutive relationship, PM4Sand model, as it has been extended to account for reconsolidation settlement. The ability of the numerical framework to capture reconsolidation settlement is validated by replicating a shake table test performed on Ottawa F-55 sand. Results are compared with a previous numerical study inspired by the same experiment. After validation, a generic numerical model is proposed, and the performance of the natural ground and the reinforced ground is compared. A parametric analysis using 12 different ground motions is performed to assess the effect of varying ground motion intensity on the post-liquefaction settlement. The analysis is also performed with the conventional PM4Sand model (without the extension for reconsolidation). Finally, simulations are performed with a footing load above the soil model. The results demonstrate that (a) the presence of stone columns reduces post-liquefaction settlement, and (b) conventional constitutive models can highly underpredict post-liquefaction settlement. Further research is required to assess the effects of (a) 3D, (b) variations in permeability, (c) parametric analysis of stone columns, and (d) densification of stone columns. / Master of Science / When subjected to an earthquake, loose saturated sand may undergo liquefaction and exhibit a reduction in shear strength due to a rise in excess pore water pressure and the corresponding reduction in effective stress. This leads to failures associated with settlements resulting from the gradual dissipation of excess pore pressures. This mechanism results in post-liquefaction settlement. Several authors have investigated the mechanism of the post-liquefaction behavior of sand and proposed methodologies to assess the deformation caused by seismic loads. They mainly conclude that the reconsolidation mechanism is characterized by a decrease in the overall soil stiffness and an increase in permeability. Among different methodologies to quantify this settlement, finite element numerical modeling is the most widely used. The primary task in performing such numerical simulation is to select the best constitutive model (i.e., stress-strain relationships) that can accurately capture post-liquefaction behavior. In this study, the capabilities and limitations of the most common constitutive models are reviewed. Moreover, the efficacy of stone columns is also assessed to mitigate the risk posed by liquefaction. Firstly, the numerical framework is validated against data from a shake table test experiment. Then, a numerical model is proposed and subjected to different seismic motions. The settlement of the ground with and without stone columns is assessed and compared for all motions. In addition, the efficacy of stone columns is also analyzed by simulating the model with a footing load. Thus, this study provides insights into the effectiveness of stone columns under different seismic motions.

Söderströmsbron is the bridge that leads the subway between Slussen and Gamla Stan in Stockholm, the capital of Sweden. It is one of the busiest routes in the entire SL traffic system. According to surveys, the ground behind one of the retaining walls in Gamla Stan has shown settlements and movements that have required Trafikförvaltning to annually fill up with 1m3 of macadam.To avoid disturbing the traffic in the area, an interference-free reinforcement method has been requested. A proposal to stabilize the soil is by injecting geopolymer, which is a two- component solution that protects against erosion and equalize ground levels. Geopolymer consist of two liquid substances, that expand in the combination with each other, forming an impervious barrier to water.This report addresses a finite element analysis in the Plaxis 2D program for the affected soil behind the support with geopolymer to determine if the reinforcement method can be applied as a long-term solution.The results from FE analyzes show that the injection of geopolymer is a more long-term solution for reduced settlements in the soil, but also for the movements of the structures. / Söderströmsbron leder tunnelbanan mellan Slussen och Gamla Stan i Stockholm. Det är en av de mest trafikerade sträckorna i hela SL:s trafiksystem. Jorden bakom landfästet i Gamla Stan har enligt undersökningar påvisat sättningar och rörelser vilket medfört att Trafikförvaltningen årligen behövt fylla på med 1m3 makadamballast.För att undvika att förhindra trafiken i området har en störningsfri förstärkningsmetod efterfrågats. Ett förslag för att stabilisera marken är injektering av geopolymer, en tvåkomponent-lösning som skyddar mot erosion och utjämnar marknivåer. Geopolymer består av två flytande ämnen som i kontakt med varandra expanderar och bildar en ogenomtränglig barriär mot vatten.Denna rapport behandlar en finita element-analys i programmet Plaxis 2D beträffande den drabbade jorden bakom stödet samt en förstärkning med geopolymer för att avgöra om förstärkningsmetoden kan tillämpas som en långsiktig lösning.Resultatet från FE-analysen visar att injektering av geopolymer är en mer långsiktig lösning för minskade sättningar i jorden, men även för konstruktionernas rörelser.

Den finkorniga sulfidjorden som finns längs Norrlandskusten är känd för sin stora sättningsbenägenhet och utgör en potentiell miljörisk genom försurning och urlakning av metaller om den inte hanteras rätt. För att förebygga miljörisker och utveckla jordförstärknings- och grundläggningsmetoder måste en ökad kunskap om sulfidjordar tas fram. I ett pågående forskningsprojekt vid Statens Geotekniska Institut studeras sulfidjords kompressionsegenskaper och rekommendationer ska tas fram avseende underlag för sättningsberäkningar. I projektet omfattas ett antal provbankar där ett av dessa områden, Lampen ligger i Kalix i norra Sverige. I detta examensarbete har det utförts numeriska analyser i finita elementprogrammet PLAXIS 2D av sättningar och portryck under en av provbankarna i Lampen och jämförelser görs med tidigare rapporterade fältmätningar. Tre olika delar analyseras i FE-programmet PLAXIS 2D. I den första delen, som är huvuddelen, utvärderas materialmodellernas, Soft Soil (SS) respektive Soft Soil Creep (SSC), förmåga att simulera de uppmätta sättningarna och porövertrycken för en period av cirka ett års belastning av provbank. Den andra delen består av en analys av de två deformationstillstånden, axialsymmetriskt och plant. De två deformationstillståden jämförs med hänsyn till sättningar och portryck. I den tredje delen utvärderas påverkan på simulerade resultat av olika nivåer på grundvattenytan, en variation som har observerats i provområdet i Lampen. Vid en jämförelse av de konstitutiva modellerna noteras som förväntat större sättningar vid användning av SSC-modellen i jämförelse med SS-modellen. SSC-modellen visar även ett högre porövertryck. Vid jämförelse med i fält uppmätta värden noteras att de mest överensstämmande sättningarna erhålls från SS-modellen medan portrycksutvecklingen simuleras bättre, men ändå långt från bra, med SSC-modellen (för simulering med dubbelsidig dränering). Vid analys av deformationstillstånd (axialsymmetriskt kontra plant) noteras en jämnare fördelning av deformationer längs banken vid användandet av axialsymmetriskt tillstånd. Den potentiella brottrörelsen som uppvisas vid släntkrön vid tillämpning av plant deformationstillstånd är inte lika tydlig vid axialsymmetriskt tillstånd. Det axialsymmetriska tillståndet visar även ett lägre porövertryck. Numeriska simuleringar av den varierande nivån på grundvattenytan som observerats i fältmätningar visar vid fallet en lägre antagen grundvattennivå en marginellt mindre sättning.  Potentiella brottrörelser blir inte lika tydliga då den lägre nivån på grundvattenytan simuleras.

This master thesis deals with a design of a Drevnovice tunnel primary lining at planned high speed rail corridor connecting Brno and Přerov. The whole design as well as defining of the most suitable tunnel excavation method are described. Thesis also contains a breakdown of the excavation, construction technology and the scheduling of geotechnical monitoring procedures. The Plaxis 2D program, based on the finite element method, was used to create numerical models of two cross sections of the Dřevnovice tunnel. Based on mathematical modeling outputs, a static calculation of the primary lining was calculated.

The thesis deals with numerical modeling of reinforced earth wall. The first part of the thesis characterizes and describes these constructions in general and also describes variations of their faces. In the next part the modeling of basic reinforced earth wall construction elements in Plaxis 2D is described. Subsequently the real reinforced earth wall is modeled and some variations of face-modeling are compared.

There are approximately 20 000 small dams in the Czech Republic. This number entails many ponds or small flood attenuation reservoirs, which provide protection against floods. We do not know much about the structure and material properties of these earth dikes. Concerning the small dam stability the current technical standard ČSN 75 2410 focuses foremost on the angle of both the upstream and downstream slopes in case of different materials, and the method of the stability assessment in case of a dam height being 6m or more. Most of these earth dikes are still standing in spite not being built according to any technical standards. They do not follow any standards mostly because they were built before the modern technical standards were published. This diploma thesis focuses on assigning the degree of a reserve in the safety factor for studies of 5 homogeneous earth dikes and 3 inhomogeneous earth dikes. The calculation was done using the Plaxis 2D software using to the shear strength reduction method. The Calculation of the safety degree is made for 4 typical load cases.

El presente trabajo de investigación tuvo como objetivo principal, evaluar el comportamiento mecánico de un suelo arcilloso de la localidad de Pacaisapa – Ayacucho utilizando residuos industriales como el caucho molido, proveniente de llantas reciclada, tiras de plástico reciclado y ceniza de cáscara de arroz aplicado estás mezclas en un muro de tierra hipotético estabilizado mecánicamente (MSE). La metodología de esta investigación consistió en realizar ensayos de corte directo NTP-339.171 y ensayos de compresión no confinada NTP-339.167 con la finalidad de obtener los parámetros de cohesión, ángulo de fricción y módulo de elasticidad del suelo. Los mismos que se utilizarán para evaluar el comportamiento de estás mezclas en el muro hipotético y modelado en el software Plaxis 8.2 haciendo uso del modelo constitutivo Mohr-Coulomb. Las combinaciones que se utilizaron fueron 30% ceniza de cáscara de arroz, 2% de PET y 10% de caucho. Los resultados obtenidos indicaron que la cohesión mejora en un 41.89% con la adición de un 30% de ceniza de cáscara de arroz y en 21.58% con la adición de 2% de tiras de plástico reciclado respecto al suelo S100, mejora el módulo de elasticidad cuando de agrega 2% de tiras de plástico en 28.78% y cuando se agrega 30% de ceniza de cáscara de arroz (CCA) mejora en 4.8% respecto al suelo puro. Además, los desplazamientos horizontales de la cara vertical del muro disminuyen al utilizar la mezcla 1 – S70CC30 y la mezcla 3 - S98P2, respecto al suelo S100. En base a lo que permite concluir que la adición de PET y CCA sí mejora el comportamiento mecánico del suelo y es posible optimizar la separación entre los geosintéticos. / The main objective of this research was to evaluate the mechanical behavior of a clay soil in the town of Pacaisapa - Ayacucho using industrial waste such as ground rubber from recycled tires, recycled plastic strips and rice husk ash applied to these mixtures in a mechanically stabilized hypothetical earth wall (MSE). The methodology of this investigation consisted in performing direct cutting tests NTP-339.171 and unconfined compression tests NTP-339.167 in order to obtain the parameters of cohesion, friction angle and young modulus of elasticity of the soil. The same ones that will be used to evaluate the behavior of these mixtures in the hypothetical wall and modeled in the Plaxis 8.2 software making use of the Mohr-Coulomb constitutive model. The combinations that were used were 30% rice husk ash, 2% PET and 10% rubber. The obtained results indicated that the cohesion improves in a 41.89% with the addition of 30% of rice husk ash and in 21.58% with the addition of 2% of recycled plastic strips with respect to the S100 soil, improves the modulus of elasticity when it adds 2% of plastic strips in 28.78% and when 30% of rice husk ash (CCA) is added it improves in 4.8% with respect to the pure soil. In addition, the horizontal displacements of the vertical face of the wall decrease when using the mixture 1 - S70CC30 and the mixture 3 - S98P2, with respect to the floor S100. Based on what allows concluding that the addition of PET and CCA does improve the mechanical behavior of the soil and it is possible to optimize the separation between the geosynthetics. / Tesis

La presente tesis tiene como finalidad establecer criterios de influencia entre parámetros geotécnicos y profundidad de excavaciones en suelos gravosos, mediante la aplicación de un software de elementos finitos. Para ello, se tomó como referencia a 5 estudios geotécnicos desarrollados en Lima Metropolitana (Santa Anita, San Isidro, Miraflores y San Luis), en donde se emplearon diversos ensayos con el fin de obtener parámetros necesarios para su modelación. Por ejemplo, gracias a estos estudios, se determinaron rangos a los parámetros geotécnicos (Ángulo de fricción, Cohesión y Peso Específico) que serán considerados en la modelación de los casos de estudio. De acuerdo con estos estudios, el Ángulo de Fricción oscila entre 25° y 46°; la Cohesión entre 10 kPa y 84 kPa; mientras que el Peso Específico tiene un rango de 18 kN/m3 a 24 kN/m3. Las excavaciones que serán evaluadas durante la presente investigación serán de 8m, 12m y 16m de profundidad y contarán también con rangos para el Módulo de Elasticidad (E50) y el Coeficiente de carga y descarga (Eur) necesarios para analizar el comportamiento físico del suelo. Los resultados obtenidos luego de emplear el Modelo Constitutivo Hardening Soil, fue que conforme van incrementado los Ángulos de fricción del suelo y el Módulo de Elasticidad (E50), los desplazamientos van disminuyendo poco a poco (estamos hablando de una relación inversamente proporcional). Asimismo, existe una relación directamente proporcional entre la profundidad de excavación, el módulo de elasticidad y los desplazamientos del suelo considerando un sistema de reforzamiento anclado. / The purpose of this thesis is to establish criteria of influence between geotechnical parameters and depth of excavations in burdensome soils, through the application of finite element software. For this, 5 geotechnical studies developed in Metropolitan Lima (Santa Anita, San Isidro, Miraflores and San Luis) were taken as a reference, where various tests were used in order to obtain parameters necessary for their modeling. For example, thanks to these studies, ranges were determined for the geotechnical parameters (Angle of friction, Cohesion and Specific Weight) that will be considered in the modeling of the case studies. According to these studies, the Angle of Friction ranges from 25 ° to 46 °; Cohesion between 10 kPa and 84 kPa; while the Specific Weight has a range from 18 kN / m3 to 24 kN / m3. The excavations that will be evaluated during this investigation will be 8m, 12m and 16m deep and will also have ranges for the Modulus of Elasticity (E50) and the Coefficient of loading and unloading (Eur) necessary to analyze the physical behavior of the soil. The results obtained after using the Hardening Soil Constitutive Model were that as the friction Angles of the soil and the Modulus of Elasticity (E50) increase, the displacements gradually decrease (we are talking about an inversely proportional relationship). Likewise, there is a directly proportional relationship between excavation depth, modulus of elasticity and soil displacements considering an anchored reinforcement system. / Tesis

Diplomová práce představuje vytvoření softwarového 2D MKP modelu přehrady Slezská Harta v České Republice za pomoci softwaru PLAXIS 2D. V úvodu práce je analýza vodní nádrže, vytvořené jako zásobárna vody a protipovodňové dílo. Analýza sleduje geomorfologii, geologii, konstrukci tělesa hráze, použité materiály a metody, a stávající monitorovací zařízení. Pro pochopení tvorby 2D MKP modelu jsou předloženy a definované metody použitých analýz - metoda konečných prvků, analýza prosakování, materiálové modely, citlivostná analýza. Následně byla definována tvorba struktury modelu - určení posloupnosti použitých analýz, definování vstupních dat a mezních podmínek a tvorba kalibračního segmentu. V závěrečné části práce je analýza dosažených výstupů rozsáhlého testování modelu, jejich korelace s reálnými naměřenými hodnotami a celkové shrnutí přínosu vytvořeného modelu pro jeho využití při předpovídání chování přehrady v extrémních případech.