The question of choosing the type of substrate for such clay soil is quite complex even for the profile specialist. There are general criteria that any developer should focus on - the features of the soil on the site, the level of its freezing and the location of underground aquifers( and their configuration).Clayey soils with an ulterior motive are classified as "problematic", as this is due to the complexity of the calculations and the construction technology itself. Moreover, there are other factors that influence the final decision.
Properties of clay
It does not "keep the shape".Clay does not "like" liquids and is easily washed away. And the foundation is constantly in contact with thawed, rain, groundwater. Therefore, there is a possibility that he will be "naked".
The material is quite plastic. It is impossible to predict with accuracy how it will behave under certain conditions( flooding, freezing, increasing load).This greatly complicates the necessary calculations.
Clay can be of several "varieties".Each of them has its own characteristics. In general, the soil is considered clay, if it contains more than 30% of the clay itself.
Alluvial
Occurs near water reservoirs, in lowland areas. Has increased plasticity and often "floats".Construction in such a locality is a risky business. It is necessary to consider the depth to which this layer lies, whether there is under it a "support" in the form of sandstone, limestone and the like.
Glacial clay
It all depends on how it lies. If it is shallow, then such a primer will be sufficiently plastic. But with a deep location of the clay foundation is able to withstand sufficient loads. Even at a depth such soil remains wet
Therefore, it will be difficult to provide a reliable waterproofing to the ribbon foundation.
These are general characteristics of clay soils. But in each area - its own characteristics. In addition, clay can be blue or red. The first water does not pass, so it creates all the prerequisites for swamping the terrain, accumulating fluid in a limited space. But the red one is water-permeable, which makes construction a little easier.
Features of construction of foundations
Belt
It is being built only in a buried type. But even here there are some nuances.
Firstly, , you need a quality "cushion".It should be thicker the greater the depth of the trench( criterion is the excess of the freezing level).
Secondly, , you need an effective waterproofing, and roll materials. It is better to use the film, since the roofing material for more than 3 - 4 years in such conditions will not serve.
Thirdly, , it is advisable to equip the fixed formwork, for example, from the plates of the penoplex, as described here. In addition to insulation, it will also provide a reliable protection against displacement of the soil( the role of the shock absorber).
Fourth , binding reinforcement reinforcement tape( wire frame).
Fifth, , the "base" of the basement should be about 1/3 wider than its upper cut. This will make the basis more stable and significantly reduce the risks of its displacement.
Sixth , arrangement of drainage system( drainage).It is necessary to ensure the maximum possible dehumidification of the site.
Slab
A more suitable option in most cases. Such a foundation is also called "floating."The main condition for its reliability is high-quality reinforcement throughout the area. Despite the high cash costs, this type of foundation is suitable for any structure. But it is necessary to take into account that foundation blocks should not lie directly on the ground. You need a good "substrate"( sand + gravel) and a preliminary screed.
Pile
As already noted, this is the most optimal option. If you managed to get to the hard ground, then the basis can not be more reliable. The difficulty is that you may need to drill deep holes deep enough. But this is a guarantee of the strength and durability of the entire structure. More details of the pile foundation are discussed in this article.
For large depths of wells, it is recommended to use screw or driven products, since it is rather difficult to pour a monolith to a higher altitude, with reinforcement. Although in some cases it is advisable to just mount the bored piles. Here much depends on the capabilities of the master, the availability of special equipment and conditions for its work.
This article is purely informative. Given the complexity of construction on clay soil, without consulting a specialist is indispensable.
