One of the key points in choosing the type, material and depth of foundation laying is to determine the depth of freezing of the soil. This factor is directly related to how reliable the construction of the whole building will be, because the stability and durability of the building depend on the quality of its foundation.
What happens to the ground in the event of frost?
As is known, water during freezing has the property of expanding. This can be easily verified by conducting an experiment with a bottle of water. If you leave it for a while in the freezer, then the glass bottle is likely to crack, and the plastic one will lose shape due to the swelling of the ice. The same happens with the water that is contained in the soil. And the higher the humidity level of the soil, the more it is prone to swelling when the temperature drops below zero.
What happens to the foundation of the building when the soil freezes?
Under the influence of the expansion of water contained in the soil, the foundation of the building is approximately the same as with the bottle from our experience. If the level of freezing of its base has not been taken into account in the design of the foundation, it undergoes deformation or extrusion towards the surface. And of course, this entails the appearance of cracks in the walls, the loosening of structural units, the displacement of floors and staircases, the scattering of plaster and other troubles. Incorrectly selected foundation material will be subjected to pressure and friction during seasonal changes in ground conditions, and eventually break down. And this is unacceptable from the point of view of safe operation - as a private house, or any other building or structure.
What determines the depth of freezing of the ground?
As we have already said, the more ground is saturated with water, the more it is subject to freezing and swelling. But first of all, of course, the temperature regime affects the depth of soil freezing. Thanks to geological surveys conducted by geologists throughout the territory of the former Soviet Union, there is a table of data that helps to know the average depth of freezing in each specific region of our country. However, the geological structure of its surface layers is so diverse that the characters of the ground can differ from each other even in neighboring areas. Therefore, the depth of freezing can be unique, depending on the composition of the soil.
Most of all, sedimentary rocks (clays, loams) saturated with water are susceptible to swelling, and the rocky ones are the least. However, often there are areas with a mixed type of soil, where swelling during freezing occurs unevenly - and this presents the greatest complexity in the design of foundations. The temperature of the projected building influences the depth of freezing of the soil. If the house provides, for example, a heated basement, then the ground will freeze less. Heated underground rooms of buildings in the neighborhood also warm the ground in the construction site to some extent.
Thus, the depth of freezing of the soil can not be the same in each section and should be measured only individually.
How do they design the foundation, depending on the depth of soil freezing?
The foundations of buildings are designed in accordance with building codes and rules - SniPam, in which formulas are provided for calculating the depth of foundation laying, depending on the depth of soil freezing. There are also norms and recommendations for selecting the type and material of the foundation of buildings. If, for technical reasons, it is impossible to lay the foundation at the required depth, based on the depth of soil freezing, the SNiPs provide for a number of saving measures: special foundation constructions, non-freezing cushions of their bases, strengthening the soil and reducing its freezing due to moisture-resistant impurities, etc.
How to determine the depth of soil freezing for construction?
So, we were convinced that to determine the depth of soil freezing it is not enough to just look at the table of regional temperature indicators. In order to properly design the foundation of the building, it is necessary to conduct a number of geological surveys in the area of future construction. These surveys include:
- analysis of the structural and chemical composition of the soil;
- study of physical properties of soil;
- determination of groundwater level;
- influence of neighboring buildings on the temperature regime and physical characteristics of the soil on the construction site and other types of research.
For these studies, we need equipment and a laboratory that our company has at our disposal. Guild Engineering conducts surveys to determine the depth of soil freezing for all types of construction in any region of our country. Please contact our specialists and your building will be reliable and durable!