Construction of a foundation on clay soils is often associated with a number of difficulties, with the greatest complexity caused by the combination of clay soil and closely located groundwater. Wet clays belong to the V group of soils due to the deformation of frost heaving, they can exert tremendous pressure on the sole and walls of the foundation when frozen. If the building is incorrectly designed, then there may be cracks, failures and destruction of the house. Therefore, when building a capital structure on clay soils, it is necessary to contact the project organization. If it is a matter of building a foundation on clay for a small house, a bath or a garage, you can do it yourself, given the recommendations given in the article.
Constructing a foundation on the clay with your own hands
Choosing the type of foundation for clay soil
The first thing you need to determine a few characteristics of the soil in your area:
- The content of clay particles in the ground;
- Soil moisture;
- Depth of soil freezing for your region;
- Groundwater table.
Soil composition is defined as follows: it is necessary to take a certain amount of soil in the hand, stretch it and try to roll "sausage".It will not work out of sand at all. Loams get the necessary shape, but soon they crack and disintegrate into separate pieces. If a solid plastic "sausage" is obtained from the soil, it is clay, one of the most difficult for the construction of soils. To determine the humidity, leave the soil for some time in the air. If the drying lasts a few hours, then the soil is wet. It is these soils that are most susceptible to frost whipping.
The level of groundwater in the site can be determined from the well or drill a hole. The depth of soil freezing is determined from the reference data, for this purpose one can use the table:
List of regions with average soil freezing in cm.
. If the groundwater level is well below the freezing depth of the ground, then after preliminary calculations, a shallow-cast monolithic band foundation can be erected. At the same time, the basement of the foundation is recommended to be wider than its upper part to increase the area and reduce the specific load from the ground. Under the base of the foundation is necessarily the erection of a thick sand cushion - it will serve as a kind of shock absorber, and also will remove excess moisture from the foundation. The foundation should be waterproofed from the outside by roll materials with high strength - this will avoid clay adhering to the foundation and shifting a large mass of soil along with the foundation when it freezes. Also, it is not superfluous to warm the soil around the foundation by creating a blind area. It should be borne in mind: if the project is carried out with the expectation of heating the basement, it can not be overshadowed - this can lead to serious deformations.
With close location of groundwater, it is necessary to install a piling foundation with piling deep at a considerable depth. In the lower part of the piles it will be necessary to perform an expansion, which will not allow the forces of frost heaving to push the foundation out of the ground.
Recently, the technology of steel screw piles is gaining increasing popularity. Screw piles are a hollow metal pipe with a pointed end, on which the blades are located. When twisting the pile, these blades are drilled into the ground, which promotes the pile to move deeper. Pile blades do not loosen the soil, unlike concrete piles, so the primer around the helical steel piles retains the initial seal.
Construction of a house on screw piles
Technology for making a foundation on clay using screw piles
- Site preparation is reduced to geodetic survey, calculation of the required number of piles and the approximate depth of their installation. Screw piles can be installed at different depths, which is convenient for areas with a strong slope or uneven type of soil. Piles must be installed in the corners, as well as in the intersection of walls. In addition, piles must be placed along the bearing walls at a distance of not less than 2 meters. After calculating the number of piles according to the drawing, check the specific load of the building for each pile, if necessary, determine the location of additional piles. The site is cleaned of construction debris and foreign objects. The soil is cut off on the entire area of the building. Make marking, marking the places of installation of piles.
Step 1 is the marking of the site for piling
- Screw the first corner pile. This can be done both manually, with the use of a lever, and with the help of a special mechanism. Clay soils are quite heavy, so it is better to choose the second option. When screwing the pile manually, it is necessary to check its verticality along the slope all the time. The slightest deviation can cause the building to skew during operation.
Installation of the first corner pile
- The following piles are screwed in the same way. It is necessary to consult the plan of the piles from time to time. Screwing the piles is performed until they reach the calculated depth, that is, below the depth of freezing of the ground and the level of groundwater. If the depth of the pile is not enough, they produce it.
The process of screwing the remaining piles into the ground
- After screwing all the piles at the hydraulic level, mark the floor level of the first floor. As a rule, it should not be less than 50 cm for residential buildings and 30 cm for a gazebo or farm building. Mark all the piles on this level and cut off the excess length of the Bulgarian.
The excessive length of the pile is cut off by the Bulgarian
- Piles for filling them with greater strength are filled with concrete of grade not lower than M200.If the depth of the piles is considerable, it must be sealed with reinforcing bars when pouring, piercing the thickness of concrete with it. When constructing a temporary structure from light materials, piles can not be poured, and then used again.
The process of pouring concrete into the
- pile For horizontal stability, the piles are tied with a beam or channel. The channel is usually used for brick or foam concrete walls, beams for houses made of timber, logs or frame structures. For binding with a bar, it is necessary to put on the piles a headpiece in which there are holes for fixing the bar. The channel is fixed by welding.
The process of tying screw piles with a beam for stability
A foundation of screw piles can be installed even in frozen ground, which is convenient for areas standing on the buoys. Due to its high productivity and short lead times, this technology has become widespread, especially in the construction of houses from profiled beams or frame structures, for popular Canadian technology. Structures on stilts can be installed on steep slopes and on the banks of reservoirs, building piers. Also on piles are often installed gazebos, terraces, other elements of landscape design.
