Probabilistic Analysis of the Active Earth Pressure on Earth Retaining Walls for c‑φ Soils According to the Mazindrani and Ganjali Method

The determination of the earth pressure coefficients (K) in geotechnical engineering is one of the most critical procedures in designing earth retaining walls. However, most earth pressure theories are made for either clay or sands, where the c-ϕ soils are the least analysed. In this paper, an analysis of the earth pressure for drained mixed soils based in Mazindrani and Ganjali (J Geotech Geoenviron Eng 123:110–112, 1997) theory was carried out. Earth pressure coefficients are generally used in a deterministic way and can represent designs under an inadmissible risk. Therefore, Reliability-based design arises as an essential tool to deal with soil variability as one of the main aspects of the geotechnical uncertainties. The influence of the soil variability in the active earth pressure for a c-ϕ soil was performed through probabilistic analysis concerning the Ka coefficient of variation (Cv) of both shear strength parameters. The sensitivity analysis shows a Cv in which the cohesion begins to have a more significant correlation with Ka than the friction angle. The results show an increase of the statistical Ka concerning the deterministic value as the soil variability and the soil slope (β) increase. Although the statistical value does not increase significantly, a statistical analysis on gravity walls and sheet pile walls in c-ϕ soils shows a significant probability of failure (pf) increase. The pf obtained through the c-ϕ variability can be considered inadmissible even if the required FS are met

Geological origin as an input variable in reliability-based designs: for an accurate exploration in geotechnical engineering

Soil is one of the most difficult materials to characterize realistically, which partly explains the uncertainty between the designs and the geostructures real behavior. Different recommendations have arisen with respect to carrying out field investigations in order to reduce the uncertainties inherent to the soil. However, the field exploration and the implementation of sophisticated geotechnical models have proven to be insufficient to mitigate the geotechnical uncertainty. Therefore, Reliability-Based Designs (RBD) emerge as a decision-making tool through the definition of the probability of failure in conjunction with the typical Factors of Safety. RBD requires a previous understanding of the most appropriate soil probabilistic models, such as the Shear Strength Varying with Depth (SSVD) analysis, traditional Monte Carlo simulations or random fields. Soil shear strength uncertainty is related to soil geological characteristics, however, geology has been commonly used in geotechnical engineering as a definition of the layers’ distribution on the soil mass, where the definition of the accurate RBD models according to the geological origin has been missing. Therefore, two geological formations were analyzed: residual soils (stationary origin) and mudflows (dynamic origin). The results show that random fields are more related to the mudflows due to the random nature of these soils, thus the exploration resources should be focused on the determination of the Probability Density Functions (PDF) and the spatial variability of the shear strength (SS) properties (laboratory tests have priority over the in situ tests). Residual soils present a higher SS space uniformity because these soils have not been previously mobilized, thus the exploration resources should be focused on the determination of the SSVD (field tests have priority over the laboratory tests). Therefore, defining the geological origin as an “input variable” will allow recognizing the most important variables and the definition of the best soil exploration for an accurate and cost-effective RBD in geotechnical engineering

Effectiveness if traditional games compared with technological games in classroom climate and student's performance in the EFL classroom : a quasi-experimental research

Tesis (Pedagogía en Inglés)The present study intended to corroborate the hypothesis that both technological and traditional games can help school students in their learning process and that traditional games unlike technological ones, also help in the creation of a better classroom climate. Through a quasi-experiment in three different educational settings, control groups and experimental ones were going to be measured both in students’ performance expressed in marks and in classroom climate measured with a sociometric test. Chile’s current national contingency has prevented this study to be concluded as expected. As an alternative outcome, the researchers carried out a perception study that compared student’s acceptance of both technological and traditional games. The result of this study shows that current students, who are digital natives, showed a slight preference for traditional games over the technological ones, defying the common belief that students only react positively to technology.El presente estudio pretende corroborar la hipótesis de que tanto los juegos tecnológicos como los tradicionales pueden ayudar a los alumnos en su proceso de aprendizaje y que los juegos tradicionales a diferencia de los tecnológicos pueden ayudar, además en la creación de un mejor clima de aula. A través de un cuasi-experimento en tres diferentes establecimientos educacionales, en los grupo de control y experimentales se iba a medir tanto el rendimiento de los estudiantes expresado a través de sus calificaciones, como el clima de aula medido a través de un cuestionario sociométrico. La actual contingencia nacional de Chile ha impedido que este estudio concluya según lo previsto. Como alternativa, los investigadores llevaron a cabo un estudio de percepción que comparó la aceptación de los estudiantes hacia los juegos tecnológicos y tradicionales. El resultado de este estudio muestra que los estudiantes, siendo nativos digitales. mostraron una ligera preferencia por los juegos tradicionales por sobre los tecnológicos, desafiando la creencia general de que los estudiantes solo reaccionan positivamente ante la tecnología

Administración de recursos de distribución: Indicadores para la priorización en transporte

Dadas las exigencias de los nuevostratados comerciales, las empresas sehan visto forzadas a aumentar sus nivelesde competitividad y volver máseficiente el manejo de sus limitadosrecursos. En este marco, es naturalque la gerencia de las empresas considereal transporte en general y ala distribución física de productos enparticular como un campo que se debeestudiar y mejorar con miras a lograruna logística comercial que redundeen disminuciones significativas decostos. En este artículo se presentael estudio de la administración de losrecursos de distribución, enfocado enla gestión adecuada del despacho demercancías, asumiendo recursos limitados.Se proponen algunas métricasque se constituyen, cuando se usan demanera combinada, como un apoyovalioso para los procesos de planificaciónde despachos considerando elcaso típico de envíos desde un centrode distribución hacia n" bodegas,las cuales podrían considerarse comoclientes internos o externos."Gerencia del transporte, distribuciónfísica, reglas para priorización dedespachos.

Estudio de viabilidad de un portafolio de proyectos de servicios de automatización de edificaciones en Colombia

En los últimos 10 años, se ha vivido una evolución tecnológica sin precedentes, y el hogar no ha sido ajeno a esta revolución -- La domótica, entendida como la automatización de las funciones típicas del hogar, ha seguido este avance tecnológico y ha comenzado a ser apreciada como algo normal y deseable dentro de los elementos de un hogar -- En Colombia, la adopción de la domótica es aún un mercado nuevo -- Los actuales consumidores nacionales de estos servicios son reducidos, y el acceso a esta tecnología es considerada como de alto precio por la mayoría de la población e inclusive, innecesario por muchos -- Sin embargo, la disponibilidad de esta tecnología a nivel mundial y la facilidad para ser distribuida y adaptada localmente, posibilita ingresar en este nuevo mercado en el país -- Con este fin, se diseñó un portafolio de proyectos de automatización del hogar, y se realizó un análisis sectorial, técnico, legal, administrativo, financiero, de mercado y de riesgos, que permitió analizar la viabilidad de la ejecución del portafolio de proyectos propuest

Influence of Limit Equilibrium Methods in the Design of Contiguous Cantilever Sheet Pile Walls Through Reliability-Based Analysis

In geotechnical engineering the design of bored- pile walls is commonly performed in terms of the embedment length (D) defined according to the limit equilibrium methods (also known as balance methods) formulated by Krey, Blum, Rowe, Hansen and the empirical method of Look in sandy soils. The limit equilibrium methods are calculations associated with the shape of the earth pressures distributions in the shaft, earth pressures theories, geotechnical properties and safety factors, while the empirical criteria establish that the relationship between embedment and the free height (H) is of the order of D/H = 1.5. These design methods are complemented by reliability-based analyzes to evaluate the uncertainties associated with soil variability and the use of deterministic concepts. The Monte Carlo method is applied to evaluate the inherent variability of soil friction angle and the soil-wall interface angle in the calculation of the stability of adjacent bored-pile walls. The results show that Hansen’s method requires a lower D/H ratio to obtain the failure probabilities of the USACE (PF = 0.001) in comparison with the other methods. The above is because the method considers that the passive earth pressure increases linearly from the excavation level to the bottom of the embedment depth, however, the other methods considers an earth pressure balance around the pivot point in the shaft. The results show that for a probability of failure established at 0.001, the obtained D/H by the Krey, Blum, Rowe and Hansen methods are 2.13, 1.97, 1.97 and 1.93, respectively. These values represent differences between 28.7% and 42.0% with respect to the deterministic design criteria of Look. Thus, the Look criterion, from the probabilistic point of view, can be considered as an inadmissible risk method, especially since it does not consider surcharge and water table

The implementation of authentic material for teaching vocabulary in an efl context

A través de este proyecto de aula, fue posible analizar cómo el aprendizaje de vocabulario en una lengua extranjera como el inglés, puede incrementar y mejorar a través del uso de material auténtico en la lengua a enseñar en un grado de primaria dentro de una escuela pública en Pereira, Risaralda, Colombia. Este proyecto se llevó a cabo en un grupo de primero de primaria, con un número total de cuarenta y dos (42) estudiantes entre los 6 y 8 años. Durante un período de tres meses con una intensidad horaria de dos (2) horas por semana en el segundo semestre de 2014. Los docentes-practicantes hicieron recolección de detalles presentados durante las clases usando reflexiones que los ayudaron al momento de escribir el presente proyecto. Gracias a la implementación de este proyecto de aula, se puede concluir que es importante que los docentes preparen clases usando material auténtico con el propósito de enseñar vocabulario nuevo a los estudiantes, pero que el docente debe tener en cuenta las necesidades, intereses, edades y capacidades de esos estudiantes al momento de planear la clase; además, la preparación de clases usando este tipo de material consume algo más de tiempo de lo normal, pero es significativo y de mucha ayuda tanto para los profesores como para los propios aprendices

Reliability-Based Designs Procedure of Earth Retaining Walls in Geotechnical Engineering

The design and construction of foundations, retaining structures and slopes are usually based on deterministic formulations that do not allow the distinction between the natural variability and the inherent dispersion in the geotechnical parameters. Due to the inherent variability of the soil properties, there is a growing trend to implement reliability-based designs in geotechnical engineering to reduce design uncertainties by probabilistic methods. The reliability designs require the definition of the probability density functions of the geotechnical properties, as well as knowledge of the spatial variability of soils. This paper identifies the procedures, type of soil investigations, simulations and the most commonly studied areas in geotechnical reliability-based designs. The importance of the correlation length in defining the reduction factors to determine the probabilities of occurrence of events, with Monte Carlo as the most used simulation method in this type of designs, is highlighted. The most commonly studied problems in this regard are related to foundation design and slope stability analyses whereas earth retaining walls and gabion walls are the less studied. Furthermore, no study was found in the determination of the variation of the soil-wall friction nor in the geological influence for this type of structures, which implies a great potential for future research in these areas

Correlations between dynamic probe blow count and undrained shear strength for peat at a well-characterised raised bog in Ireland

Peat deposits are generally heterogeneous, with large variations over small areas. Peat has an extremely high water content, high compressibility and low shear strength. This presents a major issue in studying the geomechanical behavior of peat. For this study, field and laboratory tests were conducted to establish the undrained shear strength (su) of peat at a cutover industrial peatland in Ireland which had been extensively characterized in the past. The new field work included TRL-type Dynamic Cone Penetrometer, Mackintosh probe and field vane shear tests. A correlation was developed between the Mackintosh probe “M-value” blow count and the undrained shear strength of peat. The correlation can be expressed as su=16.54M0.373. Unconsolidated undrained triaxial tests and laboratory vane tests were carried out on samples retrieved from the field. The shear strength results thus derived were lower than the field test results, but consistent with each other. The suggested reason for the reduced undrained shear strength measured in the lab is sample disturbance during extraction, transport and storage prior to testing

Implantación de plataforma Moodle para capacitaciones en empresa del sector químico

Para la empresa Químicos Pereira, la entrada de personal nuevo implica que alguien deberá capacitarlo y cuando se realiza este proceso de formación alguien debe dejar de lado sus tareas principales para poder llevarlas a cabo, esto afecta la productividad de esta persona que debe dejar de lado su puesto por períodos hasta de una semana para poder llevar a cabo las capacitaciones de personal nuevo. Se busca con este proyecto establecer un procedimiento a través del cual se formalice el proceso de capacitaciones al interior de dicha empresa, mediante el uso de las llamadas herramientas TIC, asegurando que las capacitaciones se realicen de manera tal que minimicen la pérdida de tiempo que se dedica sólo a esta labor ya que no afectarán la productividad de ningún otro empleado, se brinden a todo el personal nuevo y estén disponibles cuando se requieran