*Tropical Soils: Considerations on Occurrence and Characteristics and Studies in Brazil DOI: http://dx.doi.org/10.5772/intechopen.103947*

foresight becomes more assertive, reducing risks, costs, and creating solutions more appropriate to each situation [33, 34].

The occurrence of porous layers of clay or sandy texture and materials with varying degree of intemperization is frequent in Brazilian soil profiles, requiring in some situations, analyses and more complex models regarding the geotechnical behavior of the soil. **Figures 6** through **8** present some profiles of lateritic soils found in engineering works in Brazil.

In relation to the research methods, one of the most used in Brazilian geotechnical engineering for underground research is the survey of simple recognition of soil with SPT test as highlighted [36, 37], its execution currently governed by the Brazilian

**Figure 6.** *Soil profile along the tunnel, South Wing, Brasilia [4].*

**Figure 7.** *Profile of shear module variation for Caxingui Shaft of Sao Paulo subway [35].*

NBR 6484:2020. Despite the existence of other methods, the tendency to use this remains, either for its lower cost compared with the other methods (CPT, DMT, geophysical, or other) or for the fact that it does not require specialized labor, for the empirical correlations that are established from or by which other methods are little publicized in the universities.

This tendency of using the sounding SPT can be observed in an abreve consultation to the site of the ABMS (Brazilian Association of Mechanics of Grounds) in which nearly 100 articles are listed that wrap different applications of the method in several types of work (https://philos.sophia.com.br/terminal/8530/) as in [32, 38–43] and many other authors.

However, in some situations where the size of the work, geological complexity, or even academic studies so require, and other methods are used such as CPT (cone penetration test) or DMT (Dilatometer Marchetti Test) as well as the collection of undeformed samples for laboratório testing (triaxial compression, shear strength, deformation, modulus, and others) as exemplified by the work of [22, 30, 44–55].
