Modeling and instrumentation data analysis from excavation slope of the Misicuni Dam spillway (Bolivia): a case study

Análise de dados de modelagem e instrumentação do talude de escavação do vertedouro da Barragem de Misicuni (Bolívia): um estudo de caso

Abstract

Slope stability analysis is of fundamental importance in infrastructure projects no matter its size. The failure of a slope has a major economic and environmental impact and can turn the project unfeasible, causing irreparable damage to the environment and life. Therefore, slope stability analysis aims to evaluate the possibility of a slope suffering mass movements and to propose stabilization solutions. This research focused on obtaining the resistance parameters of the materials found in the excavation slope of the Misicuni Dam spillway applying the back analysis method and using deformational instrumentation data. The parameter modeling can support future projects in terms of mechanical behavior and safety for the Misicuni Dam in addition to subsequent engineering projects in sedimentary rock masses deformed by tectonic influence. The Misicuni Dam is part of the Misicuni Multiple Project located in the Cochabamba department, central part of Bolivia. This project consists of using water from the Misicuni, Viscachas and Putucuni river basins. To carry out this paper, three drill core investigation were used along the analysis section, as well as read out data from 2 inclinometers installed on the bench slope excavation, topographic survey and 39 uniaxial compression tests on samples collected from the drill cores. Inclinometers are instruments commonly used to monitor soil or rock slopes, and help to determine the failure surface and estimate the speed of movement. The use of inclinometer data and geological modeling made it possible to analyze and obtain stress and strain parameters that occurred during the excavation phases, by applying Finite Element Method (FEM) analysis, which allowed to compare the predicted and observed results during the execution and completion of the site. Therefore, this paper presents the resistance parameters obtained through back analysis using deformation data obtained from field instrumentation in a context of complex structural geology.