Person:
Melentijevic Devetakovic, Svetlana

First Name

Svetlana

Last Name

Melentijevic Devetakovic

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Geológicas

Department

Geodinámica, Estratigrafía y Paleontología

Area

Geodinámica Interna

Identifiers

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Now showing 1 - 9 of 9

Assessment of the Bearing Capacity of Bridge Foundation on Rock Masses
(MDPI, 2021-12-17) Alencar, Ana; Galindo, Rubén; Olalla Marañón, Claudio; Melentijevic Devetakovic, Svetlana
This paper aims to study the bearing capacity of a shallow foundation on rock mass, considering the most usual bridge footing width and adopting a Hoek–Brown material. The dimension of the foundation has been shown to be very significant in soils with linear failure criteria (Mohr–Coulomb envelope), and its study is necessary in the case of non-linear failure criteria, typical of rock masses. Analytical solutions do not allow incorporating this effect. A parametric study by a finite difference method was carried out, studying a wide variety of rock mass through sensitivity analysis of three geotechnical parameters: geological origin of the rock mass (mi), uniaxial compressive strength, and geological strength index. The results obtained by the numerical solution for the Hoek–Brown failure criterion were compared with the analytical results by adopting the classical hypotheses of plane strain conditions, associated flow rule, and weightless rock mass. The variation of the numerical bearing capacity due to the consideration of the self-weight of the rock mass was also analyzed since its influence is conditioned by the volume of ground mobilized and therefore by the width of the foundation. Considering the similarities observed between the numerical and analytical results, a correlation factor function of the self-weight is proposed. It can be used in conjunction with the analytical method, to estimate in a semi-analytical way the bearing capacity of a bridge foundation.
Rock slope stability analysis under Hoek–Brown failure criterion with different flow rules
(Springer, 2024-04-19) Melentijevic Devetakovic, Svetlana; Berisavljevic, Zoran; Berisavljevic, Dusan; Olalla Marañón, Claudio
The stability analysis of homogeneous rock slope following the Hoek–Brown failure criterion under the hypothesis of different flow rules is performed based on limit equilibrium and finite element methods. The applied failure criterion is the generalized Hoek–Brown that can be introduced as a shear/normal function in analysis applying different flow rules. The results are compared with those obtained by the application of equivalent shear strength parameters of the Mohr–Coulomb criterion, considering that this is still the most widely used criterion in rock slope stability analysis and is still the base for the shear strength reduction method applied in finite element modelling. Different proposals for estimating the equivalent strength parameters based on confining stress level are evaluated. The limitation of stress-dependent linear Mohr–Coulomb parameters is emphasized by analysing the vertical cut problem, for which, depending on the chosen stress level, different critical heights are obtained for the same material. Sensitivity analysis of geotechnical parameters used as input for failure criterion is performed to determine their influence on slope stability. Probabilistic analysis is conducted to determine the probability of failure when different flow rules are applied. If slope stability analysis is performed with an assumption of associative flow rule, the probability of failure is within the acceptable limits for the considered case study, while employing non-associative flow rule, the probability of failure is rather high. The chart is presented that could be readily used to estimate the combination of σci, GSI, and mi values that produce failure for the analysed case study.
Bearing Capacity: Correlation between Soil and Rock Correction Factors
(2019) Alencar, Ana; Melentijevic Devetakovic, Svetlana; Galindo Aires, Rubén
n the field of soil mechanics, the calculation of the bearing capacity is well developed, there are various correction coefficients published by different authors that are used to take into account diverse hypothesis regarding self-weight, foundation type, foundation roughness, etc. However, in rock mechanics the application of these correction coefficients developed in soil mechanics can lead to erroneous results, so it is still necessary to carry out more research in order to know further the influence of multiple parameters of the rock mass on the bearing capacity of shallow foundation to estimate it with more accuracy applying different correction factors. Based on the limitations of different analytical solutions for the estimation of the bearing capacity of shallow foundation on rock mass, the numerical modeling of the shallow foundation by finite difference code FLAC is performed over a great number of cases. The purpose of that numerical modelling is to study the influence of geometrical and geotechnical parameters (foundation width, rock type, uniaxial compressive strength and geological strength index) on the bearing capacity of foundations on rock mass under different hypotheses of the self-weight of material, the footing shape and the roughness of the base interface. In this paper a summary of a comparison between the influence of different correlation coefficients in soils and rocks is presented in order to determine which parameter is more conditioning in each type of material and the mechanical behavior observed, analyzing quantitatively those differences as well.
Comparación de los métodos analíticos y numéricos en el cálculo de drenes verticales como técnica de mejora del terreno bajo terraplenes
(2017) Melentijevic Devetakovic, Svetlana; Martín, Pablo
Los drenes verticales (columnas de grava y drenes mecha) son uno de los métodos de mejora del terreno más utilizados para la cimentación de terraplenes sobre suelos blandos. Conjuntamente con precarga permiten la aceleración de la consolidación del terreno mitigando los problemas con posibles asientos desarrollados durante la vida útil de la estructura. En este artículo se presentan diversos métodos analíticos existentes de análisis de la consolidación del terreno mejorado con drenes verticales comparándoloscon el cálculo mediante los métodos numéricos. En este artículo seha realizado la modelización numéricamediante el programa Midasincluyendoel estudio del comportamiento real tridimensional y las conversiones requeridas de transformación al modelo bidimensional. Se presentan diferentes metodologíasbasadas enconversión de permeabilidad,ampliándolasadicionalmente a la rigidezen el caso de columnas de grava.Se muestrala aplicación a un caso real contrastando los resultados obtenidos en términos de disipación del exceso de las presiones intersticiales y de la evolución de asientos durante el proceso de consolidación.También se analizan diferentes mecanismos de deformación de columnas de grava,en función de su situación en distintaszonas debajo de terraplenes,mediante modelos numéricosen 2D y 3D, contrastándolo con el método tradicional de análisis numérico de modelo homogeneizado en 2D.
Comparative analysis of analytical and numerical calculation methods for soil improvement by rigid inclusions
(2015) Gómez Pérez, Rodrigo; Melentijevic Devetakovic, Svetlana
In recent decades a soil improvement technique of foundation soft soils by inserting or constructing rigid inclusions has been developed. Its main application is in compressible soils under large fills or foundations of structures, optimizing the construction time and decreasing settlements considerably. Along with the development of the method, various codes and standards in different countries in Europe have been published as guidelines for analysis of rigid inclusions and different elements that make up the technique such as load transfer platform, etc. Considering the increased use of finite element modelling in different geotechnical problems, in this paper a comparison of analytical and numerical calculation methods of rigid inclusions is presented. Load transfer platform is analyzed for its different thicknesses and various separations between inclusions that defines the ranges in which analytical methods approach numerical modelling. The interaction between the soft soil and rigid inclusion for estimating ground settlements is also studied. Considering different soil stiffness, the comparison of settlements obtained by analytical and numerical methods has been done. Furthermore an analysis of the variation of the neutral point depth with the change of soft soil stiffness is performed by finite elements. This depth is decisive in the calculation of the total length of the rigid inclusion.
Evaluación del comportamiento térmico de un pilote termo-activo mediante métodos numéricos
(2018) Santiago Buey, Cristina de; Nope, Freddy; Melentijevic Devetakovic, Svetlana; Pardo de Santayana, Fernando; De Groot, María; Sartorius, Gonzalo; García, José Luis
Son cada vez más numerosas las aplicaciones de energía geotérmica de baja entalpía asociadas a la edificación o a elementos estructurales de obras civiles (túneles, pantallas, carreteras, estaciones de tren o metro). Considerando la función doble de las estructuras geotérmicas, su diseño es más complejo en comparación con las estructuras convencionales. Para el correcto dimensionamiento de tales instalaciones, es necesario conocer tanto los parámetros geotécnicos como los parámetros de comportamiento térmico como la conductividad térmica del terreno (l) o la capacidad térmica volumétrica (cv), que condicionan la eficiencia energética del sistema geotérmico suelo-estructura. En este artículo se presenta la modelización numérica del comportamiento geotérmico de un pilote prefabricado hincado en la ciudad de Valencia. Tanto los parámetros geotécnicos como térmicos de los diferentes niveles geológicos del terreno se han obtenido de ensayos de caracterización in situ y ensayos de laboratorio realizados sobre muestras extraídas de un sondeo anexo al pilote experimental. Estos datos han permitido crear un perfil litológico del terreno con información sobre la conductividad térmica de cada nivel geológico que ha servido de base para un modelo de elementos finitos para evaluar el comportamiento térmico del sistema pilote-terreno en modo verano (enfriamiento del edificio y calentamiento del pilote).
Socket roughness effect on side shear resistance prediction of rock-socketed piles
(2019) Gutiérrez Chacon, José Gregorio; Melentijevic Devetakovic, Svetlana; Senent Domínguez, Salvador; Jiménez Rodríguez, Rafael
Rock-socketed piles have been extensively employed to receive and transmit large concentrated loads to deeper stronger materials. Although the load transfer mechanism combines base and side resistances, the contribution of side shear resistance is often crucial, as it is usually mobilized at much lower strains (or pile settlements) than base resistance. The side shear resistance of rock-socketed piles has usually been estimated using recommendations from codes and standards, or using local knowledge obtained from full-scale static load tests performed in similar ground. There are also empirical formulations as a function of the uniaxial compressive strength of the intact rock. However, this approach neglects the influence of other important aspects such as the effect of roughness at the rock-pile interface, and this factor is not always being considered in current design practices. The aim of this work is to examine the socket roughness effect on side shear resistance of rock-socketed piles. To do that, DEM2D numerical models of direct shear tests, and DEM3D numerical models of rock-socketed piles with different degrees of socket roughness are employed. Numerical results suggest that socket roughness is an important factor that significantly increases the load capacity and stiffness of rock-socketed piles.
Cálculo de estabilidad de terraplenes sobre terrenos blandos reforzados mediante columnas de mezcla profunda (DMM)
(2013) Melentijevic Devetakovic, Svetlana; Morilla Moar, Pablo
Las columnas de mezcla profunda (DMM) representan una de las soluciones más adecuadas para la mejora del terreno blando bajo los terraplenes. En este artículo se presenta el análisis de la estabilidad global de un terraplén apoyado sobre el terreno blando, mejorado con columnas DMM, y la comparación de los resultados obtenidos mediante métodos de equilibrio límite (LEM) y métodos de elementos finitos (FEM). Los métodos LEM han sido tradicionalmente utilizados en los cálculos de estabilidad de terraplenes, centrándose exclusivamente en la rotura por cortante del conjunto suelocolumnas. Se destaca la importancia de la aplicación de los métodos numéricos que ponen de manifiesto diferentes posibles modos de rotura, del tipo flexión o vuelco de columnas DMM, los cuales no se analizan mediante LEM. Dado que la rotura por flexión y/o vuelco pueden ser determinantes en la estabilidad global, las mismas deben analizarse para todos los tipos de columnas rígidas o semirígidas, que poseen una alta resistencia a compresión, y muy limitada resistencia a flexión y tracción.
Simulación numérica de juntas roca-hormigón a través de ensayos de corte directo en PFC2D
(2017) Gutiérrez Chacón, José Gregorio; Senent Domínguez, Salvador; Melentijevic Devetakovic, Svetlana; Jiménez Rodríguez, Rafael
La estimación de los parámetros de resistencia al corte en la interacción roca-hormigón ha sido objeto de amplia investigación, por ejemplo, para presas de hormigón cimentadas sobre roca, para pilotes y anclajes en roca, etc. Se han realizado diversos estudios experimentales para evaluar el comportamiento del contacto roca-hormigón a través de ensayos de corte directo en condición CNL (Constant Normal Load) [1,9,10,13]. Otras investigaciones han comparado ensayos de corte directo en suelo y roca con modelos numéricos, empleando el método de elementos finitos (MEF) y el método de elementos discretos (MED) [5,6-8]. En esta investigación se realiza un análisis comparativo entre los resultados experimentales de ensayos de corte directo y los resultados numéricos obtenidos con el MED a través del código PFC2D. Para ello, en primer lugar, se calibran las micropropiedades de los materiales (roca y hormigón) a partir de ensayos de compresión uniaxial simulados en PFC2D, comparando los parámetros elásticos (módulo de Young y coeficiente de Poisson) del modelo numérico con los obtenidos experimentalmente; posteriormente, se calibran los microparámetros del plano de contacto (roca-hormigón) y, finalmente, se ejecuta la simulación numérica del ensayo de corte directo. Los resultados obtenidos indican que el código PFC2D permite modelar de manera adecuada el comportamiento de ensayos de compresión simple y corte directo.