DIY foundation pile foundationSeptember 8, 2011
If the area for the construction of any low-rise object unstable soil, then to solve this problem using pile foundation. Since the mobile soil does not give a chance of capital construction, it is necessary to get to its solid layers, and for this purpose they use a column pile foundation. It does not require a global excavation site and allows you to create a reliable and deep foundation for the building. Next, we will look at how to create such a foundation with your own hands.
The land part of the pile foundation can be no different from the usual types of bases, but under the ground it has long piles that go 5-20 meters deep. Thus, the device pile foundation neutralizes the action of unstable soil and protects the building during the change of seasons.
The main element of such foundations are piles, which can be of different types.:
- According to the internal structure of the pile can be hollow and solid;
- Geometrically distinguished rectangular, round and pyramidal piles;
- According to the material are: wooden, concrete, metal and reinforced concrete piles.
The mechanism of impact of piles on the ground is distinguished:
- Pile foundation on trailing piles;
- Pile foundation on retaining piles;
According to the installation method of piles allocate:
- The foundation on driven piles - piles driven into the soil with the help of special installations;
- The foundation on screw piles - piles made in the form of huge screws that are screwed into the ground;
- The foundation on bored piles - pre-cut holes for piles using a manual or automatic drill.
Different pile foundations and the surface part. The grillage, a bridge that rigidly connects the ground columns to form a “stand” under the building, makes them more stable.
By way of arranging jumpers distinguish:
- Foundations with team jumper;
- Foundations with a monolithic jumper.
A common option is a hybrid base, for example, a pile foundation tape. It is a combination of a shallow ribbon base and deep piles.This foundation allows you to stabilize the building on unstable water-saturated soils, so the pile foundations are the best option for areas with complex geological conditions.
Calculation of pile foundations
Immediately it should be said that when calculating such foundations, one should take into account many nuances and take various measurements, so this work should be entrusted to professionals. Calculation of pile foundations is possible only after survey work on the site. The obligatory nature of geological prospecting is determined by the diversity of soils and their characteristics, and the calculation of shrinkage and deformation of the pile foundation requires the most accurate initial data.
When surveying works receive the following data:
- The depth of soil freezing for the area;
- Groundwater level and seasonal variations;
- Characteristics of the type of soil in this area.
When calculating the future foundation, it is necessary to take into account seasonal wind loads, the weight of the building, and the dynamic load, as well as to calculate the draft of the foundation and its deformation.
How to build a tape foundation
Standard strip foundation is widely used in construction and is already thoroughly tested in practice. If its construction is impossible due to water-saturated soils, a combination of the familiar strip foundations and the installation of piles under the ground, which are driven into the tape basis, are used. Thus, the tape-pile foundation saves space under the ground and at the same time allows you to equip the standard foundation of the building, because not everyone agrees on the construction of special jumpers of the standard pile foundation under which the wind walks - the construction of the pile foundation with a grillage provides for the building to be raised by 30-60 cm .
Moreover, it is not easy for novice builders to form safer lintels for a pile foundation, and even a master without experience can build a strip foundation.
The main stages of the construction of the pile foundation include:
- Formation of trenches for non-buried strip footing. To do this, remove the layer of earth with a thickness of 5-10 cm and make the marking area. Then dig trenches and form a drainage cushion of layers of sand and rubble with a total thickness of 15-20 cm.
- Forming holes for piles.By means of the drill holes for piles are cut. In the center of the future strip footing, the holes are made for the pile with a pitch 2 meters apart. The thickness of the columns should be approximately equal to 1/3 of the width of the proposed strip foundation.
- Filling piles. A piece of roofing material is wrapped in a tube and fastened with fishing line. The resulting pipe should protrude from the soil at a third of the height of the basement. It should be noted that waterproofing pile foundation is the key to its durability. In the upper part of the pile, it is better to use a double waterproofing layer that will protect the concrete from excessively rapid loss of moisture. Having made a pipe from a material for waterproofing, a reinforcing cage of 2-3 rods with a cross section of 10 mm is placed in it, which is fixed every 50 cm with a thick wire. In this case, the reinforcement should protrude 15–20 cm from the pipe. Then, 25 cm concrete is poured into the pipe and vibropressing, thus filling the pipe to the top.
- Installation of formwork for the tape base. To do this, construct a standard wooden formwork with reinforcing cage in the middle. During this stage, the reinforcing bars protruding from the pipes are screwed to the reinforcement of the strip footing.
- Pouring the foundation. Next, carry out the standard work on pouring the foundation of the well-known technology.