Soil heaving is the process of increasing its volume due to freezing of moisture in the soil. This phenomenon occurs in different types of soil to varying degrees, and in some it is absent altogether. During construction, this must be taken into account, since a significant increase in volume can crush the foundation or violate its integrity. Therefore, foundations on heaving soils must be chosen and built very carefully. Read more about their device below.
Types of soils
Soil is a rock that is found in the upper layers of the earth's crust. According to the strength and size of their constituent particles, they are divided into the following types:
- Semi-rocky - refer to cohesive soils. They are distinguished by the ability to compact (marls, mudstones, siltstones, etc.), as well as non-water resistant rocks (gypsum-bearing conglomerates, gypsum).
- Sandy are small particles of rocks that are not linked to each other and do not have plasticity.
- Coarse clastics consist of non-linked pieces of semi-rock and hard rocks, containing more than half of the fragments, having a size of more than 2 mm.
- Clay soils consist of smallparticles smaller than 0.005mm.
- Rocky - moisture-resistant solid rocks, practically not amenable to compression.
More often construction is carried out on clayey, coarse-grained, semi-rocky, sandy and sandy-clayey rocks.
Foundations on heaving soils. How to counteract heaving
To reduce heaving and increase the strength of the foundation, you need to replace the problematic soil with sand. To do this, a pit is dug at the construction site deeper than the level to which the soil freezes. Then the resulting reservoir is covered with sand, which is an excellent basis for arranging the foundation of the house. It passes moisture well and withstands significant loads. Sand should be compacted, and then start building the foundation.
It is possible to lay horizontal thermal insulation of the soil along the perimeter of the building. This method is suitable for small houses with shallow foundations.
Foundations on heaving soils can be built below the level to which the soil freezes through. However, at the same time, freezing affects the walls of the foundation, it can harm the structure of the house. Therefore, this method should not be used in the construction of prefabricated and wooden houses with a lightweight tape base. However, it is quite suitable for reinforced concrete and brick houses.
Installing a drainage system will help remove excess moisture from the soil. To do this, use perforated pipes and lay them in a specially prepared ditch.at a slight angle of inclination at a distance of half a meter from the foundation. The pipes are wrapped with a filter cloth and covered with non-porous soil (gravel, sand). Water accumulating in the ground freely enters the pipes and flows into a well or other reservoir.
Foundations on heaving soils. Debriefing
It should be borne in mind that the choice of a specific method of counteracting heaving depends on the size and depth of the foundation, on the materials used. The size and weight of the building is also important.
