Geotechnical characteristics of mass movements in Manaus – Am

Abstract

For decades, the urban area of ​​Manaus has been expanding inappropriately, and horizontally, clearing forests and occupying unfit areas for housing. Administrative zones, like the East Zone, did not have the same evolution in their urban infrastructure as this expansion happened. Thus, mass movements arise, mainly due to anthropic factors associated with the presence of geological, topographic and environmental conditions. For the Municipality of Manaus, there is the landslide risk analysis addressed in 2012 by the Geological Survey of Brazil (CPRM) in conjunction with the Municipal Civil Defense. Currently, this risk diagnosis is made through field visits, surface investigation and completion of descriptive form in order to store information of the area under study. This methodology, described by the Ministry of Cities, is widely applied in several Brazilian municipalities with satisfactory results. In this context, the aforementioned procedure was used in the present work, and aiming to reduce subjectivity, the Hierarchical Analysis Process (AHP) was added. In the present study it was observed that this system, besides not modifying the basic approach of the Ministry of Cities method, incorporated a quantitative examination that verified the contribution (in the form of weights) of each danger indicator, besides hierarchizing the slopes with problem. Thus, it was found that the AHP method compared to that applied by the Ministry of the City were similar in the evaluation of the slopes of Jorge Teixeira neighborhood, located in the east zone of Manaus, the region object of the present study, chosen because it was more susceptible to landslide events (CPRM, 2012), aggravated by anthropogenic conditions. It is also verified that the slope stability, employing Bishop's method with the aid of Slope / W software for the slope (S01) in Jorge Teixeira neighborhood, registered results compatible with that found by the AHP method.