Good afternoon, dear guests and subscribers of the "Build for myself" channel!
The bearing capacity of the soil (its resistance) is the main parameter taken into account when constructing buildings. This characteristic shows how much pressure can be applied per unit of soil area without deformation of the structure and is expressed in units: kg / sq. cm.
Knowing this characteristic of the soil, we can always calculate the area of support of the foundation, depending on the mass of the building.
The bearing capacity of the soil is determined using an engineering-geological examination, which makes it possible to assess the soil conditions of the site with very high accuracy, for which several holes with a depth of 5 to 10 m, samples of the underlying layers are taken and by laboratory research, a conclusion is given on the type of soil, microbiological composition, GWL, density and resistance soil. The cost of such an examination is on average 27,000 rubles. (in some regions it can reach up to 40,000 rubles.)
Before proceeding with the study of the soil, I will give a table of the most common types of resistance.
Average design soil resistance (types of soil):
Also, I want to note that any soil, except for rocks, when exposed to pressure, is subject to a decrease in volume (shrinkage). And with increased humidity, the bearing properties can be reduced by almost half.
Exceptions are coarse-grained sands, the properties of which do not change with excess moisture.
So how to determine soil resistance without expertise?
In fact, there is nothing intricate. The above table will help us. And now, it remains for us to determine what kind of soil is in front of us.
With sand and clay, everything is clear, with the first - when squeezed - grains of sand remain on the palm and the soil itself crumbles in the hands, and solid clay, on the contrary, when squeezing - takes the form of a fist, when moistened - it becomes a plastic rock and a rolled ball of such soil between the palms is easily crushed by two fingers into a cake.
Further, coarse sand - grain is from 2.5 to 5 mm. Medium - 2-2.5 mm, small - 0.5-2 mm.
Sandy loam - the content of clay in such soil is about 10%, in loam - 10% -30%, so the loam will always be more plastic.
How to determine if sandy loam or loam is in front of us?
First of all, the color is visually assessed (black soil on the left, my soil on the right from the bottom of the trench). It is clearly seen that this is not sand or clay, but the color is brownish, therefore it is sandy loam or loam:
Now, I take a handful of soil from a trench dug below the freezing depth and squeeze:
Further, a ball rolls from the compacted soil between the palms:
After the ball is rolled, we try to crush it with two fingers:
With a little effort, the soil cracks and shatters into large pieces. In front of me - sandy loam, and according to the table, the calculated bearing capacity is from 2.0 to 3.0 kg / cm2. (for the calculation, you can take 2 kg / sq. cm and I won't be mistaken).
If it were clay, it would flatten without any cracks. In the case of loam, it is more plastic than sandy loam, it also flattens into a cake like clay, but there will certainly be cracks on the sides of the cake.
As you can see, you can always understand what type of soil is in front of you and approximately estimate its bearing capacity!
The second stage is moisture determination. This is done in the same way - by eye. The dug trench should stand for a day. If in a day the bottom has not dried out after excavation and the soil is as moist at the bottom as originally, we consider the soil saturated with moisture.
That's all, I really hope that the article was useful to you!
Subscribe to the channel and thank you for your attention!
Why, when removing the sewage system, it is impossible to do without a long sleeve, with a diameter of 1.5 times the working pipe (3 reasons)
Do I own part of the aerial territory if the site is in my ownership? (Explains the lawyer + laws of the Russian Federation)
In fact, the foundation does not only bear the weight of the house. Why and what is the foundation for?