Geomechanical evaluation of the Olón Cliff for stabilization pre-design of the Blanca Estrella del Mar sanctuary, Santa Elena, Ecuador

Abstract

Olón commune has one of the quietest and safest beaches on the Ecuadorian coast, among its tourist attractions stands out the “Blanca Estrella de Mar” sanctuary, which is located on a cliff approximately 40 m high. This sanctuary is part of the route of the seven churches in the Santa Elena Peninsula, which is continuously visited by tourists. Nowadays, the erosion caused by the wind, added to the rain and strong waves that hit the base of the Olón cliff directly and the anthropic activities affect the slope stability, in which block detachments have already been reported, generating risk to people and the foundations of the buildings of the place. The aim of this research is to evaluate the stability of the slope by means of the geological and geomechanically characterization for the proposal of the pre-design of the stabilization measures. The methodology of this work includes four phases: (i) drone topography and systematization of information; (ii) geological and geomechanically characterization of the area; (iii) evaluation of the stability and susceptibility to slope detachment, using the classification proposed by Chen and the parameters established by the expert method respectively; and (iv) calculation of the safety factor by the Morgenstern-Price method for proposals for stabilization. According to the results obtained, the cliff has a high susceptibility to detachment, due to its inherent lithological characteristics, low cohesion, and the anthropic conditions that have developed in recent years, for this reason the predesign contemplates multiple integrated measures, using the implementation of systematic bolt and shotcrete for stabilization, control of the drainage system towards the slope, and complementary works of periodic maintenance.