As everyone knows, the Earth on its surface is 70% covered by water. However, it is in the remaining 30% that human beings carry out most of our activities.
Due to this, geology appears, the science that studies the composition and structure of our planet, and that has been developed for more than two thousand years in order to understand how the different layers that make up the Earth behave.
This time we will focus on a branch of engineering and geology for the realization of construction projects; geotechnics, explaining its main characteristics, and looking at the main causes of soil formation.
What do we understand by Geotechnics?
The Geotechnical Engineering or Engineering Field is responsible for studying the interaction of buildings with the land and is one of the most recent branches of geology and civil engineering.
In it, the mechanical, resistant, and hydraulic properties of the materials of which the land is composed are studied. To later apply them in Civil Engineering, Mining Engineering or Architecture works. Such as in the design of the foundations on which structures are supported. such as bridges, buildings, or dams.
Within Geotechnics we can differentiate two main fields: Rock Mechanics and Soil Mechanics. To differentiate between soil and rock, we will take the definition of the father of geotechnics and Soil Mechanics, Karl Terzaghi.
“Soil can be considered to be any material from the most superficial layers of the earth’s crust that can be classified as a natural aggregate of the most superficial layers connected by weak and not necessarily permanent cohesive forces, separable by mechanical means of little intensity and energy. For their part, the rocks would be natural aggregates of mineral particles connected by strong and permanent cohesive forces, located both on the surface and in deeper layers, requiring mechanical means of great intensity and energy for their separation. ”
How are soils formed?
All the tasks that include the management of work are essential for its proper development. Among them, we can find the elaboration of
Once the difference between soils and rocks has been explained, we will go on to explain the main causes of soil formation, which are the result of the alteration and decomposition of rocks.
It is the process of alteration and decomposition of pre-existing rocks. And can be classified mainly into three groups: physical, chemical, and biological. Generally, during erosion processes, more than one type intervenes.
Physical erosion, in turn, is divided between in-situ, caused by thermal changes that cause actions and internal cracks in the rock, and that due to transport, in which the rocks decompose and disintegrate due to shocks.
Produced especially in finer soils such as clays, chemical erosion occurs through hydration, hydrolysis, dissolution, oxidation, cementation, and carbonation. Unlike in the case of physical erosion, this type, in addition to disintegrating, is capable of cementing the particles.
Finally, we have biological erosion, caused by bacterial action and microorganisms, animals, and plants. This type of soil can be easily recognized by its characteristic smell, its color, and the presence of gases.
- Transport and sedimentation
After the separation of the rock fragments, they are transported by four main agents: gravity, water, ice, and wind. The most important being water, which can carry large pieces in strong currents such as seas and large rivers.
This transport ends with the deposit and sedimentation of the particles in the ground. The granulometry of the soil will depend on the conditions in which the deposit occurs, being finer the quieter the means of transport.
- Cementation and consolidation
The previous sedimentation can lead to “loose” soils that harden over time through cementation and consolidation. This phenomenon occurs especially in arid and humid-hot climates. Where silica and carbonates cement the sand and silt particles, giving rise to stable and hard conglomerates.
By increasing the thickness of the sediments, those located in the deeper layers are compressed by the weight of the upper material, increasing their density and becoming more resistant.
In conclusion, Geotechnics is essential for the development of construction projects. And the specialized professionals who are in charge of carrying them out must have specific training. With our Geotecnical Engineering courses, you will obtain the necessary knowledge to face the challenges that will arise in your professional career.