Resumen Contexto: Los micropilotes son utilizados como elementos de refuerzo del suelo o de recalce, dicha función es comprobada y analizada por diferentes autores. En Colombia el uso de esta técnica está limitado a conceptos propios del geotecnista que involucran conocimientos empíricos y experiencias exitosas. En consecuencia, es necesaria la compilación de variables clave y metodologías analíticas y numéricas para la mejor comprensión de esta técnica. Método: En este documento se presenta un estado del arte sustentado en artículos e investigaciones que tienen como objeto el análisis y la evaluación del comportamiento de los micropilotes como elementos recuperadores de capacidad de carga en grupos de pilotes que presentan defectos. Resultados: Los hallazgos identificados en los documentos consultados logran ser sintetizados como un soporte teórico que se convierte en un punto de partida para futuras investigaciones en este campo de la ingeniería geotécnica. Conclusiones: Se logra evidenciar que los micropilotes tienen una influencia positiva en la recuperación de carga de fundaciones existentes, demostrando la importancia de efectuar ensayos y análisis de campo directamente en Colombia, considerando los estratos de suelos específicos que se encuentran en el país.

Abstract Context: Micropiles are used as reinforcing or underpinning elements, a function that has been tested and analyzed by different authors. In Colombia, the use of this technique is limited to the geotechnics expert’s own concepts, which consists of empirical knowledge and successful experiences. Consequently, it is necessary to compile key variables and analytical and numerical methodologies for a better understanding of this technique. Method: This document presents a state of the art supported by articles and research aimed at analyzing and evaluating the behavior of micropiles as load capacity recovery elements in groups of piles with defects. Results: The findings identified in the consulted documents are synthesized as a theoretical support that will become a starting point for future research in this field of geotechnical engineering. Conclusions: It is possible to evidence that micropiles have a positive influence on the load recovery of existing foundations, thus demonstrating the importance of conducting field tests and analyses directly in Colombia, considering the specific strata of soils found in the country.

Abstract In this paper a 3D numerical model using a software based on the Finite Element Method (FEM), was developed and validated using the results obtained in a geotechnical centrifuge model of a piled raft system founded in soft soils undergoing regional subsidence. The piled raft configuration had nine piles distributed in the center of the raft. The kaolin parameters were obtained, calibrated, and validated for the Hardening Soil Model (HSM), based on laboratory triaxial and oedometer test results. Also, a single pile load test was carried out in the centrifuge to get the resistance parameters used in the FEM. The developed numerical model reproduced satisfactorily soil and foundation consolidation displacements due, not only by the structural service load but also by the pore pressure drawdown. For load distribution on piles and raft, the model reproduces with good agreement the foundation behavior only for the structural service load, for pore pressure drawdown some adjustments on the embedded piles elements shaft and base resistance had to be done. The developed model allowed to identify the most sensitive parameters for this type of simulation, to define the types and stages of analysis that had the best fit for the physical model, and to obtain additional results to those measured in the physical model, e.g., the axial load distribution developed along the piles and therefore the magnitude of the negative skin friction, that is an important load that should be considered for the structural safety review of piled foundations subjected to this complex conditions.

El presente trabajo buscó evaluar en laboratorio el cambio en la resistencia mecánica que experimentan mezclas asfálticas densas en caliente cuando se adicionan, por vía húmeda, al cemento asfáltico aditivos poliméricos producto de desechos industriales del tipo plastómero (policloruro de vinilo, polietileno de alta densidad y poliestireno). Para tal fin se empleó el ensayo Marshall. De los resultados obtenidos se concluye que la resistencia mecánica de mezclas asfálticas modificadas con desechos del tipo plastómero es mayor en comparación con las convencionales (mezclas que emplean asfaltos sin ningún aditivo).

The main objective of this research Project was to evaluate in a laboratory the change in mechanical strength that dense hot asphalt mixtures go through when waste polymeric additives of plastomeric type (polyvinyl chloride, high density polyethylene and polystyrene) are added to asphalt cement, by 'wet way'. This change was evaluated using Marshall Test. The general conclusion of the experimental results was that modified hot asphalt mixtures present better mechanical behavior than conventional mixtures (mixtures which use asphalt without additives).

En Colombia, los materiales granulares de alta calidad para la conformación de estructuras de pavimentos flexibles son de difícil obtención. En algunas ocasiones el Ingeniero de carreteras debe trabajar con materiales granulares que no cumplen los requisitos mínimos de calidad de la especificación vial pertinente. En este caso el Ingeniero debe intentar mejorar las propiedades del material ya sea por medios mecánicos o químicos. En la presente investigación se utilizó desecho de PVC como material de adición, para modificar el comportamiento de una subbase granular. A partir de ensayos de Proctor y CBR se comparó el comportamiento del material natural, y mezclado con diferentes proporciones del desecho de PVC. Los resultados de la investigación muestran que el CBR de una mezcla de material granular, tipo subbase, y material de desecho, presenta un incremento notable. Además, la mezcla modificada logra cambiar el peso unitario del material, obteniéndose una mezcla con mayor resistencia y menor peso.

In Colombia, the granular materials of high quality for the conformation of flexible pavements structures are of difficult obtaining. In some cases the Engineer of highways must work with granular materials that do not fulfill the requirements of minimum quality standards of the pertinent road specification. In this case the Engineer must try to improve the properties of the material either. In the present investigation, PVC remainders were used like adding material, to modify the behavior of a granular subbase. From tests of Proctor and CBR, the behavior of the natural and mixed material with different proportions of the PVC remainder was compared. The results of the investigation shown that the CBR of a mixture of granular material type subbase and the remainder material, present a remarkable increment. In addition, the modified mixture manages to modify the unitary weight of the material, obtaining a mixture with greater resistance and minor unitary weight.