Before undertaking any project or work or building, it is necessary to know the characteristics of the land involved. To this end, a geotechnical reconnaissance of the terrain must be carried out, the objectives of which are:.

The activities and objectives of a geotechnical survey, as well as its extension and level of resulting information, depend directly on the project or work to be carried out, and the characteristics of the land where it is located. As this last piece of information is the result of the campaign, the development of a geotechnical reconnaissance should be a dynamic process, not rigidly dimensioned "a priori", but, rather, through a series of successive approaches where the need and extent of each stage was a consequence of the extent and results of those previously carried out.

However, except in rare cases, it is necessary to define the reconnaissance campaign initially, and at once, although throughout the work carried out it is not uncommon to vary the location and type of reconnaissance.

It is practically impossible to give universal rules for the design and development of a recognition campaign, since the casuistry is variable and extensive. The degree of freedom available, together with the variety of procedures for the investigation of the terrain, means that the design of the campaign responds to a balance between the economic investment, the execution period of the recognition, the importance of the work, and the consequences of a design or construction failure.

The breadth and detail of the recognition depends on the level of knowledge required. A campaign carried out for a feasibility analysis or management of solutions will not have the same entity as others established for the project, time of construction, or investigation of pathology phenomena.

Before proceeding to design a campaign, you must have as close an idea as possible of what is to be found in the recognition, to know how to look for it, and of the problems that may arise in projects or on site. Therefore, the first phase must consist of a preliminary study and a compilation of the available information.

Once this information is obtained and processed, the quantity, extension and typology of the recognitions are defined to achieve the desired goal. During its execution, this definition is susceptible to modifications.