Displacements Study of an Earth Fill Dam Based on High Precision Geodetic Monitoring and Numerical Modeling.

Luis Acosta,M Ramos,Antonio Gil,M De Lacy,Manuel Avilés,Antonio Herrera,Juan Cano

doi:10.3390/s18051369

Abstract

The aim of this paper is to study the behavior of an earth fill dam, analyzing the deformations determined by high precision geodetic techniques and those obtained by the Finite Element Method (FEM). A large number of control points were established around the area of the dam, and the measurements of their displacements took place during several periods. In this study, high-precision leveling and GNSS (Global Navigation Satellite System) techniques were used to monitor vertical and horizontal displacements respectively. Seven surveys were carried out: February and July 2008, March and July 2013, August 2014, September 2015 and September 2016. Deformations were predicted, taking into account the general characteristics of an earth fill dam. A comparative evaluation of the results derived from predicted (FEM) and observed deformations shows the differences on average being 20 cm for vertical displacements, and 6 cm for horizontal displacements at the crest. These differences are probably due to the simplifications assumed during the FEM modeling process: critical sections are considered homogeneous along their longitude, and the properties of the materials were established according to the general characteristics of an earth fill dam. These characteristics were taken from the normative and similar studies in the country. This could also be due to the geodetic control points being anchored in the superficial layer of the slope when the construction of the dam was finished.

Highlights

Dams which are large and important engineering structures storing millions of cubic meters of water have to accommodate substantial horizontal and vertical movements due to the presence of various external and internal loads
We study the behavior of an earth fill dam, analyzing deformations using high precision geodetic techniques, and those obtained with Finite Element Method (FEM)
Critical sections were considered as homogeneous along their longitude, and the properties of the materials were established according to the general characteristics of an earth fill dam

Summary

Introduction

Dams which are large and important engineering structures storing millions of cubic meters of water have to accommodate substantial horizontal and vertical movements due to the presence of various external and internal loads. When these movements, called deformations and displacements, reach certain critical limits, catastrophic damage may occur, even leading to the total collapse of the dam. It becomes a necessity to monitor such movements at certain intervals because of their significant social, technical, and economical impact [1]. Most of them are based on geodetic techniques. For example some authors have used GNSS techniques [2,3]; in other cases, Sensors 2018, 18, 1369; doi:10.3390/s18051369 www.mdpi.com/journal/sensors

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