Monolithic foundation on swampy soil. Foundation on swampy soils
If your site, which you plan to use to build your home, turns out to be swampy soil, do not be upset. Modern technology makes it easy to lay the foundation even in difficult conditions. The main rule in this case will be the correct choice of the type of foundation. It is impossible to be mistaken, because the service life of not only the foundation itself, but also the entire building will depend on this.
What is swampy ground?
Before you start building a foundation in a swamp with your own hands, you should familiarize yourself with this type of soil. It is a heterogeneous multilayer structure, which provides for the presence of:
- sandstone;
- peat;
- clay.
The swamp is always oversaturated with moisture and has large quantities of fine-grained particles. They resist compression rather weakly. The soil is unstable, so it is difficult to determine the ultimate loads.
Swampy soil is one of the most difficult to carry out construction. Before determining the depth of the foundation, the type of foundation and the area of \u200b\u200bthe structure, it is necessary to study the geological setting.
Features of construction in a wetland: geological research
If you decide to lay the foundation in a swamp for a house, then at the first stage you should carry out geological research. They are necessary to determine the parameters of the soil. It will be necessary to find out what is the volume of soil water, to what level freezing occurs, the type of soil, as well as the surface proximity of underground waters.
For soil sampling, a hand-held probe must be used. Wells are drilled on the site, which are located at the corners of the future foundation. It is better to carry out research in winter, when the soil is most saturated with moisture. Soil sampling provides the following information:
- the thickness of the layers;
- physical properties of the soil;
- depth of bedding;
- changes in the soil in recent years.
For wooden house 5-meter wells are drilled, whereas if you plan to build a stone or brick house, then the depth of the well must be increased to 10 m.
Before starting construction on a swampy area, the depth of soil freezing should be determined. If the foundation is laid to an insufficient depth, then later this can cause its destruction. As a result of engineering and geological studies, you will receive information that will allow you to determine the type of soil.
What is the best foundation to choose?
The most time-consuming and expensive process in building a house is work on the arrangement of the foundation. The cost of these manipulations will be 1/3 of the total cost estimate for the construction of the building. After a few years, any foundation in the swamp begins to collapse, but only if it does not reach the depth of seasonal freezing.
On the south side, the base begins to bulge out if the work was done incorrectly. In order for the structure to serve as long as possible, it is necessary to make drainage system... It will remove excess moisture from the site. On swampy soils, three types of foundation are used, one of which is the pile foundation.
This design is most suitable because it has the following advantages:
- relatively low cost;
- the possibility of construction in any terrain;
- increased durability;
- high resistance and strength;
- excellent corrosion resistance.
The foundation screw piles can be installed in any weather. The construction time is very short. You can complete the foundation device in 2 days. By using supports of different heights, you can smooth out uneven surfaces.
The main part of the foundation is a pile, which can be installed vertically or with a slight slope in the ground. The supports are combined with a grillage, which is a cushion in a reinforcing cage.
Screw piles for the foundation are one of the types of supports used in swampy areas. These products are protected from corrosion by zinc spraying or mastic. Screwing in is carried out using a special lever. The piles can be reinforced concrete, they are driven in with a hand head. As an alternative solution, complex composite piles are placed in the casing. They are removed after the installation of the supports and the concreting of the site.
based on bored piles
The foundation in a swamp may consist of bored piles. It is being built using one of several technologies, among them:
- with waterproofing;
- with fixed formwork;
- with removable formwork.
In the drilled wells, covers are installed, which are welded from a polyethylene film. The walls are laid out with roofing material, and concrete is poured inside. When creating a pile, you can use a removable formwork made of metal or plastic. In 2 hours after pouring, the concrete strength will be sufficient to preserve the structure. The formwork is pulled out after the mortar has solidified.
Such supports have one drawback, which is that they are not protected from moisture. But the impact of the frozen layer can be leveled by creating a sand cushion.
The foundation on bored piles in a swamp can be created according to the third method, when the formwork is not removed. In this case, it will perform the function of waterproofing. The technology provides for the use of pipes made of the following materials:
- special cardboard;
- asbestos cement;
- metal.
This method allows you to protect the piles by eliminating height differences and creating a layer of sand between the supports and.Before installing the structure, water from the well is pumped out by a pump. The lower part of the pipe, which acts as a formwork, is filled with waterproofing concrete per meter of height.
Such a foundation in a swamp requires an increase in the strength of the support. For this, frames are used from metal 1.2-cm rods. You can also use triangular designs.
Should you choose a slab foundation?
One of the most expensive, but reliable, is a slab foundation. It is able to withstand heavy loads and sudden changes in temperature. The weight of the building will be evenly distributed over the entire area of \u200b\u200bthe structure, which will eliminate the likelihood of subsidence. A sand and gravel cushion is located under the slab, which allows groundwater to pass through, preventing damage to the foundation.
Conducting construction on a wetland. Slab foundation - will it work?
If the soil is swampy, then you can equip a slab foundation. At the first stage, a shallow pit is dug, and then it is drained using pumps or drainage. Layers of sand and gravel are laid on the bottom, which are well compacted and covered with several layers of roofing material.
For pouring concrete, formwork is installed, and a reinforcing frame of 1.2-cm rods is being constructed. The prepared site is poured with a solution, and then left for several days to dry. After that, you can dismantle the formwork.
Such a foundation in a swamp is poured at a time, from above you can install strip base... It is performed on its own, is durable, and protects the walls from cracking during shrinkage. This technology is relevant for those who want to have in the house ground floor.
An alternative option is a shallow strip foundation
A strip foundation in a swamp is one of the cheapest, but relevant only for buildings made of a metal frame or wooden beams. Such a base requires a good drainage system, since the structure is laid above the freezing of the soil. The tape must be capable of resisting heaving of the soil.
The structure will rise and fall evenly with the soil. The tape will need a sand pad as well as thermal insulation for the base. Such a foundation in a swamp can be poured independently, observing the technology. The work is not too complicated.
Construction of strip foundations
If you decide to build strip foundation, then first you need to dig a trench of the desired shape. A sand pillow is laid on the bottom, and then a reinforcing cage is installed.
If water appears at the bottom, then it should be disposed of by constructing a drainage system. Next, the formwork is installed and the mixture is poured, which should be left until it solidifies. When everything is dry, the surface is covered with waterproofing.
Finally
Peatlands and marshlands are some of the most difficult soils to build. Waterlogged soils are saturated with moisture and tend to form unstable quicksands. In winter, such soil is exposed to frost heaving, and in spring - to erosion. The solid layer lies at a considerable depth, which excludes the possibility of using some types of foundation.
For wetlands, it is best to use floating foundations, also called monolithic slabs. The structure will turn out to be one-piece, thanks to this, a partial shift of the house will not occur, while distortions and destruction of the walls will be excluded.
In the process of erecting any building, first of all, you should lay the foundation. On soil with high density and low heaving, almost any type of foundation can be equipped. However, for soil with a swampy composition, certain foundation options are suitable, while the technology for their construction will differ from the standard. On the features of the construction of a foundation in a swamp, we will consider further.
How to make a foundation in a swamp: varieties and technology
The construction of a foundation on swampy soil will require more material and physical costs than the construction of a conventional foundation. In order for the foundation to serve as long as possible, it is necessary to take care not only of its insulation and waterproofing, but also of reinforcement and the creation of an effective drainage system.
There are three main options for the foundation:
- slab-type foundation;
- strip-type foundation;
- pile type foundation.
Each of them is suitable for swampy soils, however, the technology for their construction differs from the standards. Which foundation is better in a swamp, we will talk about this further.
The most reliable foundation for a house on swampy ground is a slab-type foundation. This version of the foundation looks like a monolithic slab reinforced with metal. The slab foundation is erected both for large houses and for garages, outbuildings or frame houses.
The main advantage of the slab foundation is its high bearing capacity, which is not affected by the soil underneath. The slab foundation is also called floating, since even with small movements of the soil, such as shrinkage, it moves with the soil, therefore, there is no destructive effect on the building. With technologically correct arrangement of this type of foundation, the house will be reliably protected from moisture, heat loss and others negative factors environment.
Another advantage of the slab foundation is its ability to be not only the base of the building, but also play the role of the floor on the first floor of the house. There is no need to build a screed, the floor is insulated and its finishing is carried out.
Despite this, a slab foundation requires very large material investments for its construction, in comparison with other types of foundations, in order to build a slab it will take 4-5 times more money and time for the concrete to harden.
The thickness and size of the slab depends on the weight of the building, the number of floors in it, functional purpose, the material from which it is erected, etc. All calculations are carried out individually.
The tape version of the foundation for a house in a swamp is the most common, however, it is rarely used on swampy soil. To lay this foundation, you must first of all calculate the depth at which the groundwater lies. The thickness of the foundation must be greater than this value. Therefore, you should choose this foundation only if you plan to equip the basement or basement in the house.
However, building a basement on a soil with marshy characteristics can lead to flooding, even with carefully planned waterproofing. Therefore, the strip foundation is not the best way for such a soil.
In some cases, a foundation is erected, the thickness of which is higher than the level of freezing of groundwater. This version of the foundation is called shallow. For its construction, less money and time will be required than for a deep foundation. In order to build a shallow foundation, it will be necessary to equip a pit, ensure its complete waterproofing, install a sandy and gravel padthat will remove moisture from the house. Due to the insulation, the ground near the foundation will not freeze through, and moisture will be removed through the sand. Among the advantages of a strip foundation in a swamp with your own hands, in comparison with a slab foundation, we note:
- higher speed of work;
- lower cost;
- high level of reliability;
- solidity and strength.
The construction of a foundation in a pile-type swamp is fast and low cost. This option is the simplest of the above, however, it is suitable only for low-rise construction.
In the standard installation of piles, it is recommended to install them below the depth of soil freezing. For swampy areas, there are technological aspects, according to which the soil should be first examined, and then the piles should be installed.
The upper part of the swampy soil is peat or subsidence-type soils. First, you should determine the thickness of the peat layer at the pile installation sites. Next, you should install them at the same distance from solid soil. Otherwise, the house will deform due to high pressure on the piles and on the peat soil.
Installation of pile and columnar foundations is carried out exclusively on solid ground. Piles can be different in length, the main condition for their high-quality functioning is installation on solid ground.
In order to find a solid support for the piles, the soil should be examined first. It is best to entrust this process to specialists. If the house is made of wood, then it is enough to explore the soil to a depth of 5 meters. In the process of building a stone house, the soil is studied 10-15 m deep into the swamp.
It is best if the soil assessment is done in a laboratory environment. In relation to the type of material used, when building a pile foundation, there are several of its varieties:
1. Installation of a foundation in a swamp made of screw piles.
The screwing of these elements is carried out by mechanized equipment or by hand. This foundation is very quickly assembled, literally within a few hours. It will take two or three people to complete the installation work. Installation of piles is carried out both in summer and winter. After installing the foundation, you do not need to wait time to build a house.
2. Installation of pillars.
To manufacture these elements, you will need a drill. With its help, it is necessary to equip elements in the form of holes of a certain size. On swampy soil, it is recommended to use specialized drilling rigs, since in some cases the drilling depth reaches ten meters.
3. Columnar foundation from rammed piles.
These elements are used in multi-storey construction. The principle of their construction is to install a reinforced concrete pile inside a previously made recess. For the manufacture of such a foundation, the presence of specialized equipment is required. Therefore, the choice of this foundation option is impractical in a swamp.
How to make a foundation in a swamp: technology for erecting a slab foundation
The simplest, but at the same time, reliable foundation built in a swamp is its slab version. Since the water table in such an area is at a high level, the slab will help protect the structure from moisture. The slab will also help to evenly distribute the load from the building's weight. Due to its solidity, the slab copes well with heaving soil, quicksand and all kinds of negative consequences too wet soil.
The base under the slab should be perfectly flat, otherwise, it will begin to slide to the bottom and the house will deform. In addition, the cost of working on the foundation is quite high; it will require a lot of concrete mortar, reinforcement, specialized equipment such as a concrete vibrator, concrete mixer, etc.
After leveling the surface under the foundation, the process of laying sand cushions under it follows. The thickness of the layer is about 20 cm. After laying every 3 cm, the sand should be carefully tamped. Next, you should ensure proper waterproofing, this will require geotextiles.
After that, a concrete cushion is arranged under the slab. To do this, pour about 10 cm of concrete mortar. After the concrete hardens, roll waterproofing is laid on its surface. After that, you should begin the main process of pouring the foundation in the swamp.
For this, concrete is used at least 300 marks, in addition, reinforcement is required. The minimum thickness of the base is 30 cm. To calculate this parameter, one should take into account the dimensions and number of storeys of the future structure, as well as the material from which it will be built.
If there is a large number of peat inclusions on the surface of the bog, the thickness of which exceeds 1 m, then care should be taken to remove them. Otherwise, a house that is being built of stone or brick may simply sink into a swamp. With a deeper peat bog on the surface of the bog, you should take care of additional strengthening of the foundation with the help of bored piles.
How to build a foundation in a swamp: features of the construction of a pile foundation
The installation of a pile foundation in a swamp is possible in any case, even when erecting multi-storey buildings. The main condition for the quality functioning of such a foundation is the correct calculation of the number and depth of piles.
Before you put the foundation in the swamp, you should study the soil under it. The installation of forgotten piles is carried out using specialized equipment and technology. This equipment sets the piles until they touch the hard soil under the swamp.
The installation of bored piles requires a drainage system underneath. A casing pipe is installed in the soil, then the soil is extracted through it through drilling. Installation is carried out inside the well reinforcement cage, poured with concrete mortar.
In order to get rid of air bubbles in the concrete solution, a concrete vibrator is used. After the concrete hardens, extraction is performed casing... Please note that in the process of making this foundation, the piles should be lowered to solid soil, which will easily drain moisture from it.
To make a foundation in a swamp with your own hands, you will need specialized equipment. In addition, this method is relevant when massive multi-storey buildings are being erected in the swamp.
The second option of the pile foundation is great for making it yourself, as it is relevant in low-rise construction. Depending on the design project, piles are installed inside the soil. A steel frame is welded on their surface using steel corners. This is followed by the manufacturing process of the side formwork. This is followed by the process of pouring a conventional strip foundation. If the house will be built of wood, then the process of pouring the strip foundation is replaced by the installation of a massive beam on which the entire building is held. This version of the foundation has the following advantages:
- the building is located above the ground, so it does not affect the house, the lower part of the building does not need additional waterproofing;
- since there is a gap in the lower part of the house, the building is constantly ventilated, while preventing the appearance of mold or mildew;
- before installing the screw piles, it is not necessary to level the area under the house.
In addition, this foundation is easy to install, all work is done quickly. Upon their expiration, the construction of the house continues immediately, without waiting for the foundation to shrink. To build up piles, it is enough to weld them together. However, the weld quality must be high.
The piles are quite lightweight, easy to transport, reliable and durable in operation. In order to extend the life of the pile foundation, steel piles should be treated with an anti-corrosion solution.
In the process of screwing the pile into the soil, it compacts it, thereby creating a solid foundation under it. However, such piles are only installed for small structures. They are not suitable for multi-storey construction. If you compare pile foundation with slab, then using the first option on its own will be cheaper both in terms of material resources and faster in time.
Foundation in the swamp video:
Hello everyone, today we will analyze the construction of a foundation in a swamp with our own hands.
Wetlands and peatlands are one of the most complex species soil for building houses. Swampy soils are oversaturated with moisture, in addition, due to the presence of fine-grained particles, they are prone to the formation of unstable floaters. In winter, swampy soils are subject to frost heaving, and in spring, with a rise in the groundwater level, erosion. In this case, a solid layer of soil can lie at a considerable depth, which makes it impossible to use pile technology.
It is difficult to build a foundation in a swamp, but it is possible. For wetlands, the so-called floating foundation is suitable - a monolithic slab. Due to the solid construction of such a foundation, there is no partial shift of parts of the house, which excludes distortions and destruction of the walls. When the ground moves horizontally, the slab foundation "floats" with it, maintaining the integrity of the structure. To reduce the impact of closely located groundwater, the foundation is arranged on a crushed stone embankment.
Technology for erecting a slab foundation on an embankment
- They clear and level the area for the building. It is not necessary to deepen it because of the risk of flooding. The site is covered with large gravel to a height of 1 meter. Instead of rubble, you can partially use construction waste. The bedding must mature and compact naturally, as a rule, this takes a long time, at least one year. It is possible to compact crushed stone mechanically by rolling it with heavy equipment.
- The surface of the crushed stone is leveled and concrete preparation is performed. A removable formwork is made of boards slightly larger than the size of the foundation and is poured with a thin layer of concrete, the concrete is leveled and left to solidify for several days. After that, slabs of insulation "Penoplex" or expanded polystyrene with a thickness of 5-10 cm are placed on the concrete preparation. A layer of geotextile is laid on the slabs, fastening its strips using hot air welding, the overlap should be at least 10 cm. Geotextile serves as a preparation for waterproofing and protects it from damage when the concrete preparation is destroyed.
- made of polymeric diffusion film membranes. Their high waterproofing properties not only protect the foundation from the penetration of ground and capillary waters, but also, due to the vapor-permeable structure, allow moisture to be removed from the foundation itself. The film is rolled out on a prepared site, starting from its edge. In this case, it is necessary to ensure that folds and distortions do not form. The strips of film are sealed by welding. To do this, use a building hair dryer or a special welding machine for rolled polymer waterproofing. Welding is performed in two parallel seams, leaving an air pocket between them - it is necessary to check the tightness of the weld. The ends of the pocket are welded. The check is carried out as follows: pierce the film in the place of the air pocket and insert the needle from the compressor hose there. Inflate the seam with air and wait about 20 minutes. The seam must withstand this time without deflation.
- Geotextile is again laid on top of the waterproofing roll, welding its seams. Geotextiles are covered with a thick polyethylene film, the joints of the film are glued onto double-sided tape. This multi-layer coating will ensure the slab of the foundation slides along the base and will protect the concrete from moisture penetration and point mechanical loads. Formwork is performed. It can be made both from boards and from non-removable insulation boards. On the outside of the formwork, be sure to put struts from a bar or boards in order to avoid deformation of the slab. When fastening the removable formwork, it is necessary to use nails or self-tapping screws, while positioning them so that the protruding parts are directed outward. On the formwork, it is necessary to mark the concrete pouring level.
- Reinforcement for slab foundations in a swamp must be of increased strength. It is imperative to use a corrugated bar - it provides strong adhesion of the mortar to the reinforcing mesh. The diameter of the reinforcing bar is 12-16 mm, it can be carried out according to the method. The reinforcing bar is cut to the size of the foundation and placed on plastic guides in the form of a mesh with a step of 15 cm. The reinforcement is knitted with the help of a special wire, and, given the large amount of work, it is better to buy a semi-automatic hook.
- Pouring with concrete must be done at one time to avoid seams - it is in the places of the seams that deformations of the foundation most often occur. Therefore, it is better not to save money at this stage, and order ready-made concrete. Concrete is poured using special equipment. The concrete poured into the formwork is "pierced" with a deep vibrator - air bubbles, which can subsequently create cavities and weak points, are removed. After the deep vibrator, the concrete is additionally treated with a vibrating screed - this will help to make its surface perfectly flat.
- Concrete hardening lasts at least 28 days - this is how much time the concrete gains strength and matures. For uniform drying, it is recommended to cover the surface of the foundation with a film or covering material. You can determine the readiness of the foundation using a plastic film: leave part of the foundation under the film for several hours and check it for condensation. If there are no drops, the moisture from the foundation has evaporated, and it is ready for further work.
- After the concrete has matured, the foundation must be protected from the top and sides from moisture, because freezing of concrete is more likely when it is moistened. For these purposes, use a coating waterproofing. Since the surface of the foundation plays the role of the floor of the first floor, mastic for coating waterproofing it is better to choose a polymer-based one - it has a less pungent odor. Before applying waterproofing, the concrete surface is cleaned of dust, the shells are sealed, chamfers are removed from sharp corners and treated with a primer that improves adhesion in one or two layers. After the primer has been absorbed, the mastic is applied with a wide brush or roller, the number of layers is from one to three. The side surfaces of the foundation are also insulated with plates of extruded polystyrene foam or Penoplex, fixing them with special glue. This measure not only protects the foundation from freezing, but also serves as a mechanical protection for the waterproofing layer.
A "floating" foundation in a swamp is suitable for areas with any depth of unstable layer, but its implementation requires significant financial costs. If the waterlogging depth does not exceed two meters, and there is stable soil below the swamp, and this is confirmed geodetic surveys, you can build a foundation on drill piles by analogy with a foundation on a floating boat. At the same time, the piles are deepened below the freezing depth and unstable swampy soils and firmly fixed in a solid layer. To reduce their horizontal movements, a screed is performed on top of the piles - a grillage.
Now the most acceptable way to build foundations on swampy, including structures on highly swampy and water-saturated areas, is to use screw piles. In fact, this is perhaps the most economical, and sometimes the only one possible way erection of foundations for future structures. Especially if the site is just a swamp. Screw piles in the swamp the least costly way to build a foundation for any structure, including those with a heavy load.
So, the most reliable, less expensive way to build a foundation in a swamp, heavily swampy or water-saturated areas is to use screw piles. How to fix a pile in a swamp? This question is often heard. after all, any person who is even a little versed in construction understands that any "trunk" placed in loose or highly plastic soil will not stand normally under significant load and perform its load-bearing functions. The answer is simple - it is necessary to create a power frame or, as they say now, to tie screw piles.
Binding of screw piles (power frame or armo frame) what is it and how is it done? When tying screw piles, a pile field with steel materials such as a channel or a corner, the same power frame is created. And in the case of using a channel as a connecting element, such a foundation is a full-fledged grillage.
When device foundations on screw piles in swampy areasit is always necessary to use a channel, a steel angle as connecting elements of the pile field, creating a "power frame" of the structure on highly mobile soils. In most cases, the installation of screw piles in such areas can only be done manually. This is due to a number of reasons; both the impossibility of operating equipment on such a terrain (driving and maneuvering), and the extreme complexity of the accuracy of installing piles in such soil. Both a channel and a corner are used as a strapping, which makes it possible to give the pile structure the necessary rigidity and stability on problem soils.
Installation of screw piles is produced at different depths, and at what depth? A frequently asked question is how long do you need screw piles... Of course, you need to take into account the level of freezing of your region, in particular Leningrad region - this is 150 cm. Plus the height of the foundation itself from the ground. Height can be 30cm, and 50cm, meter or more. Especially if there is a certain slope of the terrain with different magnitude of the difference in elevation. But that's not all. There are areas with very difficult soils, for example, wetlands.
Screwing the pile into the peat is not difficult enough, but will it hold on to this question? The fact is that later the piles will experience the loads of the structure and the entire mass of the building will press into the softest places of the soil. The pile itself will tend to rest against a rigid foundation, therefore, the subsidence of the structure will continue until the tip of the screw pile rests against the “hard” ground. They can be clay, dense sandy deposits, layers with stony inclusions, dense sandy loam. therefore screw pile length directly depends on the depth of dense layers.
For determining the required length of screw piles in problem soils it is necessary to carry out "geological exploration", to make test drilling. This carries additional financial costs (on average 1,500 rubles), but avoids unnecessary costs in the future. In our practice, it was necessary to screw piles up to 8 meters deep, but sometimes, apart from using screw piles, there is no longer a solution when constructing a foundation, based on cost and reliability. The latter refers to the installation of piers and berths.
Trying to save on the length of the piles can lead to unnecessary costs that can occur with full or partial repairs.
installation diagram of a screw pile in swampy soils
As described above, the pile-screw foundation may be the only one possible solution when building any building in a very swampy area. Are there any other alternatives when constructing foundations in such conditions?
Pile foundation in swampy terrain can be arranged using other pre-fabricated piles, metal or reinforced concrete. The installation method may vary. Driving piles with a special forced vibration mechanism, driving piles with a pile driving machine, installing piles into pre-prepared holes. Moreover, the latter method is rarely used even on good, dense soils. It is hardly advisable to arrange a pile foundation in swampy and heavily flooded areas, unstable soils float and collapse, which leads to a violation of the integrity of the pile shaft, deterioration of the quality of concrete and the loss of the necessary design ability of the foundation to bear the load of the structure.
Pile foundation on heaving soils arranged in the same way, and it is necessary to take into account the winter period with frequent temperature drops, as well as the snow load.
Now, in all problem areas, it is more economical and more reliable to arrange a screw foundation with mandatory reinforcement (power frame) from a channel and a corner. If all the necessary requirements are met, such a foundation will serve for a long time.
Screw piles in the swamp
What is important to consider before starting work on the installation of a screw foundation in areas with strong soil saturation with moisture?
There are some important conditions... This is an entrance, if mechanized installation is provided, sometimes shields, including in some cases with manual installation. It is often necessary to conduct geological exploration (test drilling) to find out the required pile length. In rare cases, the site is drained, with a mandatory drainage system.
1. Access roads to the site and entrance
It often happens that the entrance to the work site is in a "deplorable" state or is simply absent. In those cases when the installation of screw piles must be carried out using special equipment, the approach to the site is simply necessary for normal access to the work. There were cases when the drilling machine simply sank in soft swampy soil at the entrance and, of course, installation work was not possible. there are several ways to arrange entry to the site, different in scale and means.
"Lezhnevka" at the entrance
Laying device
bed at the entrance
The way of the entrance device when the soil is peat and solid "quicksand". Peat extraction (soil sampling) is carried out and a platform is made of logs, which then wakes up and is tamped with suitable material, most often sand or sand-gravel mixture. Such an entrance will allow the normal conduct of work and further maneuvering of equipment during the construction process.
Plank or board platforms
The platforms are temporary entrances for the duration of the equipment operation. Scaffolds can be made from fortieth boards or plywood boards. Any materials ready to withstand the technique will do.
Shields at the entrance
Also, these shields are shifted, if necessary, at the very site of work for the duration of the equipment.
2. The condition of the soil on the site itself
It often happens that the site is very saturated with water, the area of \u200b\u200bthe site has become degraded after heavy rains, under a dense layer of soil there is quicksand.
Shields
Shields in a highly waterlogged area
If the piles are twisted using special equipment and the soil is not very muddy, but only the top layer, then you can resort to shields made of wooden materials.
Shields on problem soils
Geotextile
Geotextile
If the site is "swamp", then you will have to sample the soil to the required depth, lay geotextiles and fill everything with sand, ramming to the required density.
Correctly carried out preparatory work on areas with problem soils will make it possible to qualitatively install the pile-screw foundation.
For installation, please contact tel. 981 — 84 — 08
Few people will be pleased with a site located in a wetland. But you shouldn't think ahead of time that it would be better if it weren't. Until the situation is completely cleared up, you just need to be patient. In fact, the foundation is being built in the swamp, although this is fraught with certain difficulties. First, geological studies of soil layers are carried out, inviting specialists. Based on the results, conclusions are drawn and a responsible decision is made about the possibility of conducting construction works... Only after that, calculations are made, taking into account the conclusions provided, and it is determined which foundation in a given territory will be installed.
Research
Swampy soil refers to difficult soils. It:
- has a multilayer, heterogeneous structure;
- consists of unstable peat, heaving clay and sandstone;
- differs in different density and high water saturation of layers.
In such conditions, it can be difficult even for professionals to determine which of the foundations will be better and more reliable to make on swampy soil so that it can withstand the bearing loads from the house. Geological studies of the area where problem soils are located help to clarify the situation.
For soil sampling, several wells are drilled on the site - at least four. They are usually placed in the corners of the future home. If it is assumed that its sides will be too long, then the intake holes will have to be made more. The wells for sampling are carried out by means of a hand-held probe. It is not at all necessary to buy it - the invited specialists probably have such a tool.
For a wooden house, a well is drilled to a depth of at least five meters, and for a more massive brick house, within eight to ten meters.
In the course of research work, long before the builders begin to erect the foundation in the swamp, it is possible to find out the parameters of each of the soil layers lying on the building site, namely:
- thickness;
- composition;
- chemical and physical characteristics;
- water saturation;
- depth of occurrence.
Besides, modern methods allow us to understand how the soil structure has changed in recent years under the influence of seasonal and climatic influences. The most important are the periods of snow melting and prolonged rains. For our latitudes, they coincide with spring and autumn. At this time, the soil, especially swampy, is saturated with water, which in the worst way affects the bearing capacity of the soil.
The instability of swampy soils is one of the main problems that complicate the construction of buildings on them.
An important indicator is the level of soil freezing, which directly affects the depth of the foundation, mounted on peat soil. e... The value of the GTU is tabular and is taken depending on the region of construction.
All the data obtained is analyzed and then voiced in the form of recommendations. The parameters determined in the course of research are taken as initial indicators for technical calculations.
Under normal conditions, the underground part of the house requires almost a third of the financial costs provided for in the estimate documentation. It would be reasonable to assume that a peat foundation would attract a much larger amount into the construction process. In this regard, before starting work, you should carefully weigh everything, and also decide on your financial capabilities... Saving in such situations is irrelevant - neither in materials, nor in labor.
In order for a house built on swampy soil to serve for a long time and not rise above the planning mark as a result of seasonal freezing, it is first necessary to make a drainage system on an still empty area. Its functions will include lowering the water level in the built-up area, and later on in the exploited area. If necessary, during the period of work along the perimeter of the site, they additionally dig a trench for the construction of a temporary drainage ditch, leaving it open. This will allow surface water to be diverted from the site.
As practice has shown, the most successful options for swampy soil are three types of foundation:
- piles;
- shallow tape;
- unburied slab.
Let's consider each of them separately.
Metal and reinforced concrete piles
A pile peat foundation has quite a few advantages:
- lack of large-scale earthworks;
- device in a short time;
- undemanding to the layout of uneven terrain;
- carrying out work in almost any weather;
- the stability of the house while observing technological processes;
- durability.
When building a foundation for a house, piles can be used:
- screw;
- reinforced concrete;
- bored.
Screw piles do not need special mechanisms, so a small "home" team can mount such a foundation in a swamp with their own hands. Metal products are screwed in by hand until the pipe tip is in a strong and stable ground layer. The level of its occurrence is determined based on the results of preliminary geological studies. According to the same indicators, it is calculated what height the screw piles should be, taking into account their elevation above ground level.
Reinforced concrete piles are immersed by indentation or vibration. For this, unlike screw counterparts, it will be necessary to attract heavy mechanisms. Bored piles are installed according to their own technology. All nuances are indicated in project documentation and technological maps.
Strip foundation
Shallow structures are used for light structures, which include wooden frame houses... The tapes are laid above the depth of soil freezing, therefore, in the winter period, they are exposed to the pushing effect of frost heaving forces. But this does not cause serious damage to the house, since the structure on a rigid reinforced concrete tape rises and falls without violating the integrity of the structure.
It should be noted that a well-made sand cushion, laid under the foundation on peat, significantly compensates for the seasonal movements of the ground part of the house. The underground structure is additionally insulated, which reduces the problems associated with heaving soils.
Today, a shallow strip foundation is the most economical option for arranging a foundation on swampy soil.
Slab foundation
A reinforced concrete slab is located under the entire area of \u200b\u200bthe house. The technology of its laying is reduced to the fact that at the initial stage a meter layer of soil is removed at the site of the future structure, the bottom of the pit is rammed, after which a sand and gravel cushion is laid out under the foundation in layers. In other words, there is a partial replacement of the problem soil under the future slab.
Next, the formwork is installed and the waterproofing layer is laid. Then the reinforcement mesh is mounted and the slab is poured concrete mix... The cushion in the slab foundation acts as an expansion joint between heaving soil and a slab, which, in turn, distributes the loads from the structure as evenly as possible.
The slab construction for a house built on swampy soil is considered reliable. But for the owners of problem areas, it costs more than the first two options for the foundation device.
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