Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Construcción e instrumentación de un terraplén experimental para el estudio de la interacción atmósfera-vegetación-suelo

Auteur : Cevallos Luna, Andrés Sebastián

Université de soutenance : Universitat Politècnica de Catalunya

Grade : Màster en : Enginyeria del terreny 2017

Résumé
The present investigation is part of the SMuCPhy project “Slope mass‐wasting under climate change. Physical mechanisms, predictive modelling and possible mitigation strategies” which is being developed by researchers of the UPC. This work focuses on the work package entitled “Full‐scale experiment soil/plant/atmosphere interactions”. Prior to this research other works like the one proposed by Oorthuis in 2016 as a final work of master were performed in the framework of the project. Based on Oorthuis (2016), the construction of an experimental embankment was conducted as a fundamental purpose of this work. Prior to the construction, experimental tests were conducted in the laboratory to obtain characteristics of the Agropolis and to prove the proper performance of the sensors. Based on the SUCS classification, the material tested (samples taken in Agrópolis) is a clayey sand with a low liquid limit (LL = 34). Also the maximum dry density (1.87 g/cm³) and optimum moisture of material (13.8 %) were determined in the Standard Proctor test. The permeability of the material was obtained through different procedures. An empirical relationship between permeability and the void ratio was obtained. The retention curve of the soil was obtained with the instruments that had been placed on the embankment, resulting a value of 47 kPa for the value of the parameter P0 in the expression of van Genuchten. We performed nineteen unconfined strength tests. Also dynamic cone penetration tests were done in the laboratory and “in situ” conditions. Samples were extracted out of the embankment to obtain the water content and natural density of the soil. For field conditions, an unconfined compression strength of 20 kPa was estimated on the basis of the dynamic penetration tests. Several sensors have been installed to measure variables such as temperature, volumetric water content, suction, and other environmental parameters. In laboratory, several tests were performed to know if the devices needed any adjustments to work well with the Agropolis soil. Any specific correction of calibrations supplied with the sensors was necessary. The main part of the research was the construction of the embankment, this document describes in written form and graphically the differentstages of construction. The installation of the sensors was a thorough job. As the embankment construction, mounting process of the sensors is been graphically described using photographs and diagrams of the location of the sensors. Up until today, the embankment is in test phase. Finally a brief analysis of the month data collected was done. The behaviour of the sensors observed during rain episodes and drying periods responds adequately to the environmental conditions. The data obtained will allow the calibration of numerical models, which is one of the main objectives of the project SMuCPhy

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