Estudo geotécnico da camada de cobertura final do aterro sanitário metropolitano oeste de Caucaia (Asmoc), Ceará

Abstract

The objective of this study was to evaluate the geotechnical conditions of the final cover layer of the Western Metropolitan Sanitary Landfill of Caucaia (ASMOC), in which its activities ended in mid-2021. In situ and laboratory tests were carried out for geotechnical and geomechanical characterization of the studied soil. . An equipment called Humbolt GeoGaugeTM was also applied to measure the stiffness and elasticity modules. The analysis of the movement of the superficial landmarks was carried out with the objective of understanding the behavior of the massif regarding the speeds and directions of displacement. The cover soil was classified as silty-clay sand. presenting, therefore, a friable behavior regarding the stress x strain relationship (cohesion of 7.8kPa and friction angle of 34.1°). The density curves found are typical of soils with low compressibility. The stiffness and elasticity modules of the berms varied, on average, between 10.2 MN/m and 88.2 MPa; while for the slopes these values were between 5.1 MN/m and 44.1 MPa, suggesting that the berms respond better to the compaction process. The 14 surface landmarks analyzed showed displacements in different directions and directions, which suggests that the massif is undergoing reconfiguration due to settlements. On the other hand, the displacement speed was below 2.5 cm/day, which is considered an acceptable limit for ASMOC operation. The set of tests applied to the soil of the final cover of ASMOC was assertive, as it made it possible to obtain soil parameters that are very common among Brazilian landfills. The GeoGauge proved to be useful when used as an additional device to existing tests to obtain geotechnical parameters of soils.