Study of the Phenomenon of Quicksand in the Geotechnical Laboratory

The quicksand phenomenon occurs when the sand particles are saturated by an upward flow of an aqueous fluid and microscopically the particles of the mineral lose contact. Thus, the tension of the soil weight equals the water pressure value making the effective tension of the soil null. The sandy soil does not present plasticity and cohesion, when saturated the sand loses its mechanical characteristics and acts like a liquid. The objective of this paper is the elaboration of a didactic physical model, in laboratory, that simulates the phenomenon of quicksand and the development of a better understanding of its occurrence operations and characteristics. The methodologies used were quantitative and qualitative. The quantitative methods were geotechnical characterization tests, such as the classification of sands in terms of granulometry (ABNT NBR 7181: 2016), specific mass test and the development of a permeameter capable of determining the permeability coefficient in a BMA (system that is composed of gravel, geodrenant mesh and sand). The methods of quantitative character were the analyses of the phenomena in reduced scale and the behavior of the sands in the BMA system. The results found coincide with the expected physical properties. This was possible due to the fact that the glass apparatus was adequate to promote and watch the quicksand phenomenon, besides, the BMA system was important to maintain the permeability constant in all the simulations carried out in the laboratory.