Avaliação do risco a escorregamentos devido a ocupação urbana na vila Bela Vista em Santa Maria - RS

Abstract

The study of geological and geotechnical characteristics of the slopes and indication of eviction those considered high risk geotechnically, can prevent tragedies caused by landslides materials. This dissertation was the main objective of evaluate the landslide risk due to urban occupation on the slope of strand west hill Cechela located in the Bela Vista village of the municipality of Santa Maria-RS. The methodology applied in this work consisted in review of the literature, field investigations, laboratory tests for characterization and determination of the resistance parameters of the soil layers, survey report of the intervention area, registration of housing under conditions of high risk to landslides, stability analysis of the slope of strand west hill Cechela and comparison of risk observed with that presented in the Municipal Plan of Reducing Risks of Santa Maria (PMRRSM). The results of inspection report are: the hillside with slopes greater than 30% is located in area not suited to urban occupation; there are deposits of small thickness colluviums situated directly on the substrate sandstone bedrock of the formation Botucatu; the most significant processes of instability on the slope are the landslides planar shallow colluvial soils. The register of homes indicates that if not done containment works two houses should be removed. The results of direct shear tests indicated that the increase of humidity and saturation degree cancels the cohesive intercept and significantly reduces the angle of internal friction of colluvium and sandstone. However, under natural conditions no saturation occurs due to the local geological conditions. The stability analysis with the use of software obtained safety factors (FS) of 1.40 and 2.57 for profiles of 07 and 17 HOUSES, showing that the slopes of the hill are stable. The landslide risk observed in the study area is less than that indicated in the PMRRSM. This work shows that must be constructed surface drainage devices and/or containment of the soil near the House 07 and 17 sites and suggests that today's families are kept in the slope of strand west hill Cechela. It is noteworthy that the village community Bela Vista should be instructed with relevant information to the identification of risks and the municipal plan risks should be reviewed.