Causes of Deformations of the Foundation

The construction of any house begins with a foundation. There are many types of foundations (belt, pile, slabs, etc.), but they all serve one single purpose - to transfer the load from the structure to the soils. But recently there has been an interesting trend - people turn to designers, get calculations and build, without knowing the geological structure and properties of the grounds on which the house is to stand. Sometimes a house costs for years and nothing happens, and sometimes, when immediately, when after a few years, cracks suddenly appear, the doors stop opening, etc. And the reason is often hidden in the features of the engineering and geological conditions of the construction site, more precisely in the processes that occur in the interaction of the foundation and the ground (poor quality materials and construction errors will be left aside). Let us dwell on them in more detail.

The most frequent processes are: irregular precipitation, frost heaving, flooding. Less often there is suffusion and even less often landslide processes. This is not a complete list, we can go on and on, but let's look at the processes already mentioned, their causes and ways of dealing with them.

Uneven precipitation occurs due to the different bearing capacity of soils under identical loads. A vivid example: one corner of the house rests on dense loam, and at the second angle - a peat lens. Obviously, the building will roll toward this lens. The problem is solved (more precisely not allowed) by applying a competent foundation construction based on calculations that should be based on engineering and geological survey materials.

Frost whipping occurs only in clayey and silty soils. To exclude its influence on the foundation, the depth of the deposit must be no less than the depth of freezing, and the lateral surface of the foundation must be isolated from the ground to prevent frost. Another option is a sand cushion 50 cm thick and the same lateral insulation.

Flooding is the process of raising the level of groundwater to a certain critical level. For protection use external waterproofing. It should be noted that in clay soils often formed perch, so save on waterproofing is not worth it.

Suffasion is the process of mechanical transfer of ground particles by groundwater. It develops only in raznozernistyh sands. It is difficult to deal with suffosion, so it is better to provide a foundation that is capable of holding a building without deformations, even with small voids under it. Optimum option - a stove.

Landslides are relatively rare, but insidious geological processes. They occur when the slope of the slope is from 3 degrees, the depth of capture can be from several tens of centimeters to hundreds of meters. If your house is built on a slope, you should turn to a serious office and make a calculation of sustainability.

So, let's summarize: all the described problems with the foundations arise because of insufficient study of the geological structure, or in general, the lack of information about it. You should not save on research. If the foundation is the foundation of the house, then the exploration is the foundation for the design of the foundation. The calculation takes into account the physical and mechanical properties of soils (the module of general deformation, density, etc.), and the nature of the geological section (types of soils, their thickness, peculiarities of occurrence). Research provides information on groundwater, which is sometimes a decisive condition for choosing the type of foundation.