Caracterização geotécnica do solo em lagoa de infiltração em início de utilização

Abstract

The functioning of the cities generates sediments which are carried by the rains to the drainage system, accumulating in the points of final destination of the water, where there are the stormwater infiltration basins. There are several ways to reduce the arrival of sediment to the drainage device, but over time there will always be accumulation at the bottom of the basin. In this way, the retention of fine materials and also of organic matter ends up reducing the permeability of the soil used as draining material, leading to the clogging process. With this, the infiltration basin can start to operate above its capacity and stop being part of the solution to the floods. In addition, water retention also slows the recharge of the region's water table and serves as a breeding ground for mosquitoes. In this way, the objective of this work is to begin the study of the soil’s clogging process in the stormwater infiltration basin, located at the Federal University of Rio Grande do Norte, Natal, RN. For this purpose, samples were taken from the material and tests were performed in order to obtain its geotechnical characteristics and also the organic matter content deposited in the soil. In situ water infiltration tests were also carried out to determine the permeability coefficient of the material. The tests were carried out in October 2016, the first month of operation of the system. The results were not favorable to the good performance of the drainage device, being the soil composed of a poorly graded clayey sand with an organic matter content that could reduce the permeability by up to two orders of magnitude. These results will be used as initial parameters so that, over time, the development of soil’s clogging can be evaluated.