Determinación del coeficiente sísmico para estudios de estabilidad en el macro-deslizamiento Guarumales

Abstract

Equator, located in the Pacific Ring of Fire, registers moderate to high seismic hazards. April 16th of 2016 in the coastline on Pedernales city the country suffered a 7,8 magnitude earthquake that coasted 663 lives and millions in material loss. One of the most destructive effects of seismic activity is the induction of landslides. This work studies Guarumales landslide, located in the oriental foothills of the Andes Mountains. There lies the Electric Corporation of Equator (CELEC) campsite for one of the most important hydroelectric projects in the country, Project “El Molino”. The fundamental methods for slope stability evaluation are limit equilibrium analysis and stress-deformation analysis. The most used procedure is the pseudostatic analysis, which is based in limit equilibrium. The objective of this study is to determinate the seismic coefficient for a pseudostatic slope stability analysis for Guarumales landslide. Usually the seismic coefficient is a fraction of the maximum horizontal acceleration. Bray and Rathje (1998) propose that fraction is a function of the ground motion parameters (magnitude, distance, duration of the earthquake and mean period of the earthquake). The American Society of Civil Engineers Los Angeles Section Geotechnical Group recommends this criteria to reduce unnecessary conservatism. The obtained seismic coefficient is lower than the previously used due to the reduction of uncertainties that the over simplification of a dynamic phenomenon to a static analysis. This method is recommended for slope analysis, however further prospection is needed if actions are meant to be done.