SPT (Standard Penetration Test)
This is one of the most frequently used techniques of dynamic penetration in conducting surveys and geotechnical recognition, due to its economical benefits and the allowence of soil collection.
It allows us to determine the most important geotechnical parameters for the characterization of soils, such as soil stratigraphy, cut resistance, relative density and support capacity.
It consists of measuring the number of strokes necessary for a cylindric and hollow spoon to be introduced 15 cm down (with a dimension of 51 mm in diameter and 35 mm of hollow space in its interior where it allows to take soil samples), with a constant frequency, a mass of 63.5kg on the head which is placed in the upper part of the linkage at a free height of 76 cm.
The number of blows or resistance of penetration gives us an idea about the capacity of support of the land. In addition, it allows us to obtain an altered sample of soil to analyze in the laboratory. If the number of hits is greater than 50, it is indicated as a rejection and the test is considered finished.
The data obtained is important for the calculation of the load capacity of surface foundations, allowing recommendations on the foundation system to be used, the layer of soil where the foundations are laid, the compaction of the ground, determine the susceptibility to liquefaction by earthquakes and the local stability of the works.
