Detailed knowledge of soil characteristics is extremely important for the implementation of various engineering projects and ventures. Through stratification, it will be possible to understand the behavior of the subsoil and make safer and more efficient decisions for that type of location.
This article will provide a better understanding of the purpose of exploring the relevance of soil stratification reports within the context of... engineering Geotechnical engineering. Furthermore, it will be easier to understand what its objectives are and how this procedure is carried out to achieve success.
What is soil stratification?
The process of soil stratification for grounding is a common practice in electrical engineering. The main objective is to create a grounding system that is both efficient and safe. Grounding itself is necessary to protect people and equipment from potential electrical discharges.
This process involves constructing a series of conductive and insulating materials in the ground area. Through this step-by-step process, it is possible to improve the efficiency of the grounding system, as well as design the layers to direct electrical currents in a completely effective way.
What is the purpose of this procedure?
Among the main objectives of soil stratification are:
- Reduction of soil resistanceThrough a proper stratification procedure, it is possible to reduce soil resistance. This will cause an even greater amount of electrical current to be dissipated. This type of action is important to prevent the accumulation of static electricity, ensuring a proper path for currents to ground in case of a fault in the electrical system.;
- Improvement in the distribution of electrical current.It is through soil stratification that there is a correct and uniform distribution of the electric current flowing towards the ground, preventing concentrations in specific points. This type of process is important in areas with a high density of electrical infrastructure, where dozens of current sources may be connected to the same system;
- Minimizing the impact of eddy currentsIf the procedure is performed correctly, it will also help reduce the effect of eddy currents, which are unwanted currents that can arise from the interaction of different electrical systems close to each other.
Stratification process
For soil stratification for grounding to be carried out, it is necessary to use conductive materials in the process, such as grounding rods, aluminum or copper cables, and also insulating materials, such as clay granules, bentonite or sand.
All materials used are arranged in alternating layers on the ground itself, based on the specific project and the characteristics of the construction site. It's also worth mentioning that the layering must be done by qualified professionals, as applicable standards and regulations must be followed.
How to check the soil?
The methodology for testing soil resistance must be carried out according to NBR 7117-1, which will show the necessary methods for an efficient geoelectric sounding. Furthermore, it will also define the techniques for determining the model that corresponds to horizontal layers, as well as parallel and planar layers.
Therefore, soil testing can be performed in the following environments:
- Wind farms;
- Hydroelectric Power Plants;
- Industrial Plants;
- Photovoltaic parks;
- Substations with an area greater than 20,000 m²
Based on its application, the values that indicate the soil resistivity can be grouped as follows:
- Low resistivity;
- Average resistivity;
- High resistivity.
In electrical engineering, the first layer is defined as a superficial, dry layer, or one with a lower water content, containing organic matter, and exhibiting average resistivity. Following this, the second layer consists of saturated soil, below the water table, composed of fractured rocks.
Finally, in the last layer, there is the bedrock, composed of layers of compacted sediments or crystalline rocks, with a resistivity ranging from medium to high.
What are vertical electrical soundings used for?
Vertical electrical soundings are seen as a geophysical method used to investigate subsurface characteristics in order to obtain information about soil stratification, including its electrical resistivity, as explained in the previous topic.
This information is indispensable and valuable, as it ensures greater project effectiveness and improves the efficiency of the lightning protection system. Its main purpose is to provide data on the electrical resistivity of the soil at various depths within the same terrain.
It is through this data that the best location and configuration for grounding electrodes can be found. These electrodes will need to be positioned in soil layers with low electrical resistivity, aiming for adequate and efficient dissipation of electrical current towards the ground, reducing risks to the environment.
In general, the main objective of a soil assessment report is to reinforce environmental safety, as well as to provide better quality for ongoing projects, reducing the chances of failure.
