Mapping proposal of sliding susceptibility applied to Rio-Santos Highway in São Sebastião - SP

• Grant number: 16/25241-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2017
• End date: April 30, 2018
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Fábio Augusto Gomes Vieira Reis
• Grantee: Débora Andrade Targa
• Host Institution: Instituto de Geociências e Ciências Exatas (IGCE). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

São Sebastião - SP is related to the geomorphological context of Serra do Mar, which is known by its steep terrains and escarpments. The Rio-Santos Highway is a very important road that contours the north coast of São Paulo State and goes until Rio de Janeiro - RJ, passing through São Sebastião. This highway is frequently affected by mass gravitational movements mainly during the rainy periods. The main causes for these events are related to the bigger soil exposure that has been increasing due to deforestation and anthropic occupation. The rainfalls decrease the soil cohesion and the friction between the particles, causing huge displacements of geological materials, like rocks and soils. In order to avoid and prevent sliding and flows, a geological-geotechnical study is vital to understand the geotechnical behaver of the area. This project consists in a mapping proposal of sliding susceptibility applied to Rio-Santos Highway in São Sebastião (SP), between Maresias and Enseada beaches. The research has five steps: the first one consists of a data survey about all that has already been done about the study region and a compilation of all this data in order to create a topographic base at scale 1:50000; the second step refers to production of auxiliary materials and the photointerpretation of satellite imagens of the study area according to the method proposed by Zaine (2011), aiming the texture and relief elements with the view to delimit the area in geotechnical units, as well as the elaboration of map of sliding scars considering previous sliding events; the third step is related to the field work that aims to describe and to collect samples of soil along the road for geotechnical laboratory tests and to analyzed and to make some in situ tests in rocky massifs in order to obtain their geomechanical classification; the fourth step corresponds to the geotechnical laboratory tests for the soil samples; the last one consists in the compilation of the data, result analyses and correlation between attributes and sliding and the confection of a geological-geotechnical map at the scale 1:50000. The project will provide a good geotechnical characterization of the study area, focusing in the susceptibility of sliding occurrence from the data analyzed along the development of the research. So, it will be possible to contribute to future civil constructions and the urban planning of the São Sebastião, reducing the risk of accidents. (AU)