Geotechnical drilling is one of the main techniques used in ground investigation, as it enables us to understand the structure of the subsoil and obtain samples for analysis. It forms part of geotechnical ground investigation and is essential for carrying out geotechnical studies in engineering and construction projects.
Geotechnical surveys make it possible to characterise the materials present, assess their behaviour and determine the parameters required for the design of foundations and other structural solutions.
At GEOSERVIN, geotechnical surveys are carried out as part of site investigation programmes for civil engineering, building and infrastructure projects, ensuring that reliable data is obtained for geotechnical analysis.
What is a geotechnical survey?
What is a geotechnical survey? It is a drilling operation carried out in the ground with the aim of obtaining direct information about the nature and characteristics of the subsoil.
During the survey, soil and rock samples are taken and the various layers of the ground are recorded, enabling the stratigraphic structure and geotechnical properties to be determined.
The boreholes form part of the geotechnical ground investigation campaign.
Correctly carrying out borehole investigations is key to ensuring that the data obtained is representative and can subsequently be used in the geotechnical analysis of the site.
Why are geotechnical surveys carried out?
Geotechnical surveys are used to obtain key information that enables the safe and efficient design of a project’s construction solutions.
Site characterisation
They enable the identification of the various materials present in the subsoil, their distribution, and their physical and mechanical properties. This information is crucial for defining the geotechnical model of the ground and assessing its behaviour under the project loads.
Collecting soil and rock samples
During the survey, samples are taken and subsequently analysed in the laboratory to determine geotechnical parameters. These tests enable the precise characterisation of soil properties and reduce design uncertainty.
Assessment of foundation conditions
The data obtained makes it possible to determine the ground’s bearing capacity, its deformability and other key factors for the design of foundations. This facilitates the selection of construction solutions suited to the actual site conditions.
How a geotechnical survey is carried out
A geotechnical survey is carried out using a technical methodology that combines drilling, data logging and sampling.
The quality of this work has a direct bearing on the reliability of the geotechnical study; consequently, its execution and supervision require technical expertise and continuous on-site monitoring.
Drilling equipment and methods
Specialised drilling equipment is used, tailored to the type of terrain and the depth of the investigation. The methods may vary depending on whether the ground consists of soil or rock.
Sample collection and recording
During drilling, soil samples are taken, recorded and classified. This process enables the sequence of layers and their characteristics to be identified.
Tests carried out during the survey
Inside the borehole, in-situ tests can be carried out, such as penetration tests, which provide information on the strength and behaviour of the ground.
This work is usually carried out as part of geological and geotechnical fieldwork services.
At GEOSERVIN, the execution and supervision of geotechnical surveys form part of investigation programmes tailored to each project, ensuring the quality of the data obtained and its consistency with the objectives of the study.
This type of work has been carried out on civil engineering, water infrastructure and renewable energy projects, where soil characterisation is key to ensuring the technical feasibility of construction solutions.
Types of boreholes used in geotechnical investigation
There are various types of geotechnical investigations, depending on the purpose of the study, the required depth and the characteristics of the ground:
- Mechanical drilling with core sampling.
- Rotary drilling in rock.
- Soil investigations using standard penetration tests (SPT, CPT).
- Drilling using geotechnical instrumentation.
The choice of borehole type depends on the project and the level of detail required in the geotechnical investigation, as well as the ground conditions.
The importance of geotechnical investigations in civil engineering projects
In civil engineering projects, geotechnical investigations are essential for reducing uncertainty regarding the ground and improving the reliability of the design.
The information gathered during the surveys makes it possible to:
- Define geotechnical calculation parameters.
- Identify any potential risks associated with the site.
- Optimise the design of foundations and structures.
- Minimise unforeseen issues during the construction work.
The results of the surveys are incorporated into the geotechnical study of the site, where they are interpreted and translated into technical recommendations for the project. This enables informed decisions to be made and the design to be optimised from the earliest stages.
This approach is routinely applied in real-world projects, where the information obtained from ground investigations enables the design to be adapted to site conditions and risks to be minimised during construction.
