Avaliação do potencial de colapsibilidade de solos do estado da Bahia através de métodos diretos e indiretos

Abstract

Some unsaturated soils are susceptible to the phenomenon of collapse due to their complex behavior when they come into contact with liquids. The basic characteristic of collapsible soils is the shrinkage of the soil after wetting. The high values of voids and porosity, low initial moisture content and the unsaturated condition of the soils are factors that favor collapsibility Some soils of the state of Bahia were studyed seeking to identify whether they are affected by collapsibility through physical characterization tests, simple edometric test (SET) and double edometric test (DET). Through direct and indirect methods, the potential of collapse of the studied samples was evaluated. The collapse was determined in the flood condition for the 200 kPa pressure in the SET. The results obtained through direct methods showed high collapsibility for both samples. The potential for soil collapse ranged from 7.70% to 18.30%, being classified as "Collapsible" and "Problem" according to the criteria of Vargas (1978) and Jennings and Knight (1975), respectively. The compressibility curves of the flooded and unsaturated samples allowed to classify the soils as conditioned to collapse, that is, the soil collapses with wetting and increased overload. The indirect methods showed some inconsistencies in their results, which shows the need for care when using them. The presence of potentially collapsible soils was identified in the municipalities of Cruz das Almas and Morro do Chapéu.