Pile foundation on swampy soil. What foundation to make in a swamp: a pile foundation. How to make a slab foundation

Modern construction technologies allow the construction of a residential building on a swampy area. The choice here is important, which foundation is better in marshland.

And its reliability and strength is already a difficult task due to the bearing capacity of the soil, which is prone to deformation. The disadvantage of such a site is the possibility of changing the density of the soil, which is especially dangerous in winter.

Soil moisture freezes and threatens to swell in the vicinity of the base and have a destructive effect on it.

The structure of such soil is multi-layered and heterogeneous. It comes with the content of clay, peat soil, sandstone and has a different density. Oversaturation with moisture and a large number of fine-grained particles contribute to the weak resistance of the fundamental base to compression.

Because of this instability, it is quite difficult to determine the load-bearing limit. Before determining the type of foundation, its area and the depth of laying, the geological composition of the site is carefully studied.

Soil research

At this stage, the geological situation on the land plot is carried out. At the same time, such soil indicators are determined as: the mass of soil water, ground type, its level of freezing and the location of underground sources relative to the earth's surface.

The soil is sampled using a hand probe. To do this, preferably in the spring, a 4th recess is made on the land plot. This time of the year was not chosen by chance, during this period the soil is especially saturated with moisture.

Soil research provides data on: components, physical properties and thickness of its layers, the depth of their location, soil changes in recent years.

Under the structure of wood, a well is made from 5 m in depth, under structures made of brick and stone - 8–10 m.

An important factor is the depth of soil freezing. Insufficient laying of the fundamental foundation in depth contributes to its destruction.

Foundation types

The construction of the foundation is the most time-consuming and expensive construction stage, whose cost for marshy soil is almost 1/3 of the total cost of the entire construction. With non-seasonal freezing, it is guaranteed destruction after years.

If the work is done incorrectly, its southern direction will “bulge” out of the ground.

Whatever foundation would not be considered better in a swampy area, for long-term operation it is necessary to create a drainage system to remove excess fluid from the land allotment. The following types are recommended for such sites: a monolithic base, on piles and a shallow foundation.

Foundation on piles

Tools required when building a foundation on piles:

Level;
Sledgehammer and hammer;
drilling device;
Shovels;
Bulgarian.

Pile elements are driven into the ground to the required depth with special equipment or a sledgehammer. Using bored pile supports, they are screwed in.

Due to their length, they pass through dangerous swampy areas, falling into layers with a higher bearing capacity, which will serve as a reliable foundation. Wooden pile supports are not recommended due to their poor water tolerance.

The use of reinforced concrete supports is optimal. After driving them, a grillage is arranged in the form with holes for pile elements.

The function of the grillage is to distribute loads from the building. Next, they raise the walls, make floors, roofs and other components of the structure.

The walls are raised after the concrete has gained sufficient strength after 2-3 weeks. Supports of different heights contribute to smoothing out the unevenness of the earth's surface.

Slab variant

Working tools and materials:

Shovels and tape measure;
Hammer and nails;
Automatic mixer;
Saw and grinder;
Film;
Sand material and water;
Gravel material and concrete mix M200;
Wooden boards;
Reinforcement Ø 10-12 mm.

To begin with, the soil layer is removed by 1 m. The one made is then carefully compacted with gravel. All this contributes to the elevation of the site under the foundation.

With a properly laid cushion, groundwater has a free exit under the base, which helps to reduce heaving on frosty days and evenly distribute the pressure of the structure on the soil.

Additional stability of the structure is due to the non-buried structure.

After - with obligatory vibration pouring of concrete. The bottom of the base is equipped with stiffeners. The pouring of the monolith is done at a time. There is a concrete strip on top.

Shallow Ribbon

Its cost is much lower than other options, but it is provided only for lightweight structures made of wooden beams and metal frame structures. Requires a well-thought-out drainage system, laid above the level of ground freezing.

This option is monolithic, therefore, due to its own rigidity, such a base is able to withstand the effects of ground heaving, it is characterized by uniform raising and lowering along with the soil, which allows it to maintain its shape.

A sand cushion is also preliminarily made and the base is insulated.

When choosing which foundation is best in swampy areas, this option is ideal for frame construction using wood or metal. It is very important to ensure the reliability of the construction of the foundation, which should last for many years, to strictly observe the technology of its construction.

Here is a video on the topic of the article:

Therefore, special attention is paid to such an important element as sandy flooring, which contributes to the minimum effect of the heaving phenomenon. Also, do not forget about the process of thermal insulation of the lower base and the arrangement of the drainage system.

Thanks to following strictly defined instructions, everyone will be able to build and equip such a structure on absolutely any terrain.

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 foundation option 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 the foundation in the 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 last 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 foundation;
tape type foundation;
pile foundation.

Each of them is suitable for swampy soils, however, the technology for their construction differs from the standards. The foundation in the swamp is better, we'll talk about this later.

The most reliable foundation for a house on marshy ground is a slab foundation. This version of the foundation has the form of a monolithic slab reinforced with metal. The slab foundation is being built both for large houses and for garages, outbuildings or frame houses.

The main advantage of a slab foundation is its high bearing capacity, which is not affected by the underlying soil. The slab foundation is also called floating, because even with small soil movements, such as shrinkage, it moves with the soil, so the building does not have a destructive effect. With technologically correct arrangement of this type of foundation, the house will be reliably protected from moisture, heat loss and other negative environmental factors.

Another advantage of the slab foundation is its ability to be not only the foundation of the building, but also play the role of the floor on the ground floor of the house. There is no need to build a screed, the floor is insulated and its fine finish is performed.

Despite this, the slab foundation requires very large material investments for its construction, compared to other types of foundations, in order to build a slab foundation, it will take 4-5 times more money and time for concrete to harden.

The thickness and size of the slab depends on the weight of the building, the number of floors in it, the functional purpose, the material from which it is built, 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 should first of all calculate the depth at which groundwater occurs. The thickness of the foundation must be greater than this value. Therefore, this foundation should be chosen only if you plan to equip the basement or basement in the house.

However, building a basement on soil with swampy characteristics can lead to flooding, even with carefully planned waterproofing. Therefore, a strip foundation is not the best option for such soil.

In some cases, a foundation is erected, the thickness of which is higher than the freezing level of groundwater. This version of the foundation is called shallow. Its construction will require less money and time than for a deep foundation. In order to build a shallow foundation, you will need to equip the foundation pit, ensure its complete waterproofing, install a sand and gravel cushion at the bottom of the trench, which will remove moisture from the house. Due to the insulation, the ground near the foundation will not freeze, 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 one, 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 only suitable for low-rise construction.

In the standard installation of piles, it is recommended to install them below the freezing depth of the soil. For swampy areas, there are technological aspects, according to which it is necessary to initially examine the soil, and then install the piles.

The upper part of the swampy soil is a peat bog or subsiding soils. First, the thickness of the peat layer at the pile installation sites should be determined. Next, you should install them at the same distance from solid soil. Otherwise, the house is deformed due to the high pressure on the piles and on the peat soil.

Installation of pile and column 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 piles, you should first examine the soil. It is best to entrust this process to specialists. If the house is made of wood, then it is enough to examine 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 carried out in the laboratory. In relation to the type of material used, during the construction of a pile foundation, there are several varieties of it:

1. Construction of a foundation in a swamp from screw piles.

The screwing of these elements is carried out by mechanized equipment or by hand. This foundation is very quickly mounted, literally within a few hours. Two or three people are required to complete the installation work. Installation of piles is carried out both in summer and in winter. After installing the foundation, you do not need to wait for time to build a house.

2. Installation of pillars.

For the manufacture of these elements will require 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 of stuffed 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 availability of specialized equipment is mandatory. Therefore, the choice of this foundation option is impractical in a swamp.

How to make a foundation in a swamp: technology for building a slab foundation

The simplest, but at the same time, a reliable foundation built in a swamp is its slab version. Since the groundwater level of such an area is at a high level, the plate will help protect the building from moisture. The slab will also help distribute the weight of the building evenly. Due to its solidity, the slab copes well with heaving of the soil, quicksand and all sorts of negative consequences of too wet soil.

The base under the slab must be perfectly flat, otherwise, it will begin to slide to the bottom and the house will be deformed. In addition, the cost of working on the foundation is quite high; pouring it will require a lot of concrete mortar, reinforcement, specialized equipment, such as a concrete vibrator, a concrete mixer, etc.

After leveling the surface under the foundation, the process of laying a sand cushion under it follows. The thickness of the layer in this case is about 20 cm. After laying every 3 cm, the sand should be carefully compacted. Next, you should ensure proper waterproofing, this will require geotextiles.

After that, the arrangement of the concrete cushion under the slab is carried out. To do this, pour about 10 cm of concrete solution. After the concrete has hardened, a rolled waterproofing is laid on its surface. After that, you should proceed to the main process of pouring the foundation in the swamp.

For this, concrete of at least 300 grades is used, in addition, reinforcement is required. The minimum base thickness is 30 cm. To calculate this parameter, the dimensions and number of storeys of the future building, as well as the material from which it will be built, should be taken into account.

If there are a large number of peat inclusions on the surface of the swamp, the thickness of which exceeds 1 m, then care should be taken to remove them. Otherwise, a house that is built of stone or brick can simply sag in a swamp. With a greater depth of peat on the surface of the swamp, care should be taken to further strengthen the foundation with the help of bored piles.

How to build a foundation in a swamp: features of building a pile foundation

Installation of a pile foundation in a swamp is possible in any case, even during the construction of 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. Installation of forgetful piles is carried out using specialized equipment and machinery. This equipment sets the piles until they touch the hard ground beneath the marsh.

The installation of bored piles requires the arrangement of a drainage system under them. A casing pipe is installed in the soil, then soil is extracted through drilling through it. Inside the well, a reinforcing cage is installed, which is poured with a concrete solution.

In order to get rid of air bubbles in the concrete solution, a concrete vibrator is used. After the concrete has hardened, the casing is removed. Please note that in the process of making this foundation, the piles should be lowered to solid soil, which will easily remove 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 in the case when massive multi-storey buildings are erected in a swamp.

The second version 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. The following is the process of manufacturing 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 bar on which the entire building is held. This version of the foundation has the following advantages:

the building is 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 fungus;
before installing screw piles, it is not necessary to level the area under the house.

In addition, this foundation is easy to install, all work is carried out quickly. Upon their expiration, the construction of the house immediately continues, without waiting for the foundation to shrink. To build piles, it is enough to weld them to each other. However, the quality of welding must be high.

Piles are quite light, easy to transport, reliable and durable in operation. In order to prolong 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 itself. However, such piles are installed only under small buildings. They are not suitable for multi-storey buildings. If we compare a pile foundation with a slab foundation, then the use of the first option in independent execution will be cheaper both in terms of material resources and faster in time.

Foundation in the swamp video:

If you got a wetland for building a house, you don’t need to be upset, with modern technologies it is possible to build a house in a marshy area. The main thing is to choose and build the foundation correctly - the basis for the house. And we will tell you which one is better on swampy soil.

Description of marshy ground

This is a multilayer heterogeneous structure, which includes clay, peat, sandstone and has a different density. It is supersaturated with moisture, with a large number of fine-grained particles that resist little compression. The instability of the soil leads to the fact that it is difficult to determine the limit of the load that it can withstand. Therefore, swampy soil is considered the most difficult for building a house. Before determining the type of foundation, the area and depth of its laying, a thorough study of the geological situation on the site is necessary.

Geological studies of the soil

They are needed to determine the main indicators of the soil. These include:

volume of soil water;
soil type;
the level of soil freezing;
surface proximity to groundwater.

It is necessary to use a manual probe for soil sampling. At least 4 wells must be drilled on the site (at the corners of the future foundation). It is better to do this in the spring, when the soil is most saturated with moisture. Soil sampling provides the following information: composition, physical properties and thickness of the layers, their depth, soil changes over the past few years.

For a wooden house, you need to drill a well with a depth of 5 m or more, for brick or stone houses - 8–10 m. Do-it-yourself foundation on swampy soil can be built if professional geologists make an assessment of the state of the soil.

It is important to consider the depth of soil freezing. Insufficient depth of the foundation can lead to its destruction. The information obtained as a result of engineering and geological research will help determine the type of foundation that is right for you.

Types of foundations for swampy soil

Work on the arrangement of the foundation is the most time-consuming and expensive stage of construction, which, on swampy soil, is at least one third of the total estimate of all the costs of building a house. Long-term studies have shown that any foundation on swampy soil begins to collapse after a few years if it does not reach the depth of seasonal freezing. On the south side, where the soil is most moist, it begins to "bulge" out of the ground if done incorrectly.

Therefore, in order to foundation, erected in the swamp with your own hands, served for a long time make a drainage system. It makes it possible to divert excess water from the site. On swampy soils, three types of foundations are used. Let's take a look at these types.

pile foundation

This type of foundation is considered the most suitable for swampy soil. It has the following advantages:

relatively low prices;
short construction time (can be built in 2 days);
construction can be carried out with any terrain;
work can be carried out in any weather;
increased durability and resistance to corrosion;
increased strength and stability.

The use of piles of various heights makes it possible to smooth out uneven surfaces of the construction site. Its main part is the pile itself, which can be installed vertically in the ground or by making a slight slope. They are combined with a grillage (concrete cushion in a reinforcing cage).

In swampy areas, the following types of piles are used:

Screw piles in a metal shell. They are protected from corrosion with mastic or zinc coating and screwed into the ground using a special lever.

Reinforced concrete piles (driven into the ground with a manual pile driver).

Complex combined piles. They are placed in a casing pipe, which is removed after the piles are installed and the site is concreted.

slab foundation

Reliable, but one of the most expensive types. It withstands sudden changes in temperature and heavy loads. The even distribution of the weight of the building over the entire area of the foundation does not allow it to sink, and the sand and gravel cushion located under it allows groundwater to pass through without harming the foundation.

The construction technology is as follows:

A shallow pit breaks out (up to about 1 meter deep).
It must be drained, using drainage or using pumps (if there is a lot of moisture).
At the bottom of the pit, layers of sand and gravel are laid, which are carefully compacted and covered with several layers of roofing material.
To pour concrete, formwork is made and a reinforcing frame of at least 12 mm is constructed.
The prepared area is evenly poured with concrete mortar and the slab is allowed to dry for several days. Dismantling the formwork.

Needs to be filled in one go. A strip foundation is erected on top of it. Such a base can be made on its own, it is durable, protects the walls from cracks during shrinkage, and allows you to build a basement.

Shallow strip foundation

This is the cheapest foundation, but is only suitable for light structures made of wooden beams and metal frames. He needs a good drainage system, because it is laid above the freezing of the soil. They make it only monolithic, which allows the shallow foundation, due to its own rigidity, to resist heaving of the soil, evenly rising and falling along with the soil. He also needs a good sandy "cushion" and insulation of the base of the foundation.

In our time to lay do-it-yourself foundation on a swampy area and building a house with the observance of modern technologies is not difficult. The main thing is an accurate calculation and a great desire, the rest is a matter of technology. Keep it up, you can do it.

Example with expert comments (video)

The foundation is one of the main construction tasks, which ensures the durability and reliability of the entire building. But not only the strength of the basis depends on the correctness of the installation work. The soil in this case has an important role, namely, its features. Therefore, when choosing the type of foundation, you need to focus on this parameter.

Features of the foundation in the swamp

The foundation for a house in a swampy area requires special attention. After all, in addition to the bearing load from the mass of the house, it also experiences the plasticity (mobility) of the soil, which can lead to such problems in the future:

Partial or complete flooding of the house during the heaving season when the groundwater level rises;
Uneven distribution of the load on the basis, which can lead to the destruction of the task in the area of the foundation or along the bearing walls;
Constant dampness in the house and the spread of fungus from the side of the floor, etc. However, such problems can be avoided if you choose the right type of foundation for the house on swampy and waterlogged soils.

The fact is that the composition of the soil in the swampy area is quite diverse and may include peat layers, sand, clay, quicksand, etc. Such combinations inevitably lead to constant movement of the soil. Therefore, it is so important at the design stage to conduct a preliminary analysis of the soil by drilling several control wells and taking the soil from them for analysis. You can order soil research on the construction site in special organizations. The service, of course, will cost a pretty penny, but the architect will be able to correctly calculate the bearing capacity of the foundation in the future.

Foundation types for swampy soils

You can build a house in a swampy area if you follow all the nuances of the installation technology. And as a foundation for a house, you can choose these types of foundations.

Pile basis

The best option for a foundation for a house in a swamp. At the heart of such a foundation are monolithic reinforced concrete or bored piles. Sometimes their depth can reach 15-20 meters, depending on the amount of groundwater in the area and the degree of soil heaving. But the house on such piles will feel secure and strong for many years. Even with strong heaving, the building will remain in its place. The pile foundation can be mounted both in summer and at sub-zero temperatures. Work is completed in 2-3 days.

Important: below the mark of 20 meters, the pile has simply already overcome the swampy layer of soil and rested against dry layers, which makes the supports even more reliable. However, it is worth remembering that it is impossible to build such a foundation on swampy soil on your own. This will require sophisticated drilling equipment. Although the cost of purchasing all the material themselves is not so high.

However, it is worth remembering that piles are not recommended to be mounted in those soils that are prone to horizontal shifts. In this case, even the strongest piles may not withstand the horizontal pressure of the layers over time and simply break. Which will lead to the destruction of the house over time. On such soils, it is better to mount a foundation slab.

Slab monolithic foundation

This type of foundation fits perfectly on swampy soil and is a monolithic reinforced concrete pad. It is also called a floating foundation, due to the peculiarity of the basis to maneuver in the soil during heaving seasons. That is, the base will simply repeat the movement and direction of the soil, withstanding significant loads. The depth of such a plate should reach 1.5-2 meters in order to go into the ground below the freezing level of the soil. It is better to pour a slab-type foundation in the summer, when the groundwater level in the swampy area goes as deep as possible and opens up the opportunity for craftsmen to work dry.

Important: it is desirable that the base of the foundation go beyond the design parameters of the building by 40-50 cm.

As another type of foundation for building on a swampy area, a shallow slab foundation can be presented. This is the same floating slab that goes into the soil by only 50 cm. But it is worth remembering that such a foundation can only be built for light-weight frame or timber houses on one floor. A large mass of the house (if you mount a brick or block cottage) will simply break the foundation with resistance from the ground during heaving seasons.

Do-it-yourself foundation installation: choose the type of work

If you do not know which foundation is better to mount on a swampy area with your own hands, then give preference to a slab. This type of basis, even with large amounts of work, can be completely done with your own hands. As special equipment, you only have to rent an excavator to prepare the pit and a construction mixer with a ready-made solution. Everything else can be done on your own.

If you prefer a pile foundation, then you should know that it is better to trust the work to professionals. Since only craftsmen can clearly control the evenness of the well under the pile, its depth and uniformity of filling the column with mortar. In addition, only a competent operator can work with drilling rigs.

Execution of work on the device of the slab base

In this section, you will learn how to make a monolithic floating foundation in a swamp. First of all, it is worthwhile to understand that it is better to perform work in the second half of summer in dry weather. It is during this period that all groundwater is located as deep as possible.

It is good if the developer already has project documentation in his hands. It is along it that the axes are broken down in the area under the base. That is, stakes are installed around the entire perimeter of the future foundation and control cords are pulled between them. Do not forget to increase the base plate by 30-50 cm from all sides.
Now is the time to excavate the soil to a given design depth. For this, it is better to use a bucket, since earthworks will have to be done independently within 2-3 weeks. Yes, it's hard physically.
The bottom of the prepared pit is well rammed and covered with a layer of crushed stone 20-30 cm thick. It is also compacted with high quality. And the next layer of the cake becomes the same thickness layer of sand. It is moistened and rammed until there are no traces on the sand during the attack. When performing this stage of work, it is necessary to clearly align the walls of the pit with a shovel for the installation of formwork.
Now formwork is installed in the pit, which should exceed the ground in height. This is done to form a plinth 30-50 cm high.
The bottom of the pit and the walls of the formwork are covered with roofing material, overlapping the joints and smearing with bituminous mastic. Such waterproofing will prevent the contact of the concrete base with groundwater and prevent the leakage of concrete milk into the ground, which could reduce the final strength of the foundation.
Then, steel reinforcement is installed in the pit in the form of meshes connected from steel rods. For every 50 cm of foundation thickness, there should be one grid associated with a cell size of 20x20 cm. All transverse grids are interconnected by longitudinal rods. It is important to remember that the reinforcement should be buried in concrete 5 cm above and below and 2-3 cm from the sides of the slab.
Now you can fill the monolithic base with a ready-made solution. Taking into account the fact that it will require tens of m3, it is better to order ready-made concrete. Grade 400 or 500. This type of mixture will provide a greater bearing capacity of the base. It is necessary to pour the solution in one stage, since the gradual mixing of the solution and its pouring lead to a violation of the installation technology of the slab base and a decrease in its final strength.

The filled base is covered with a film and left for 3-4 weeks until completely dry. In the early days, the plate must be moistened periodically so that the mixture does not dry out abruptly. After a month, the slab is completely ready for further construction work.
As soon as the slab has completely hardened, the base can be backfilled. For these purposes, you can use clay soil, which will act as an additional waterproofing for the monolith. In this case, the clay must be well compacted during backfilling.

Important: according to the same principle, a shallow slab foundation is also mounted. Remember, a well-made basis is the key to the durability of a house on marshy ground.

What is more profitable

- with walls made of flexible timber or brittle aerated concrete? In each case, the answer to this question will be different.

How to make a foundation for a country house in areas with swampy soil.

Plots with weak wetlands are considered unfavorable for building a house in terms of soil conditions.

You can build a house on any soil, you just need to do it right.

Soil properties in wetlands

Wetlands are characterized highly compressible soils. These soils include:

Loose sands and sandy loams, water-saturated fluid-plastic and fluid consistency with a porosity of more than 41%.
Loams with a porosity of more than 50% and clays with a porosity of more than 52%.
Peaty sandy and clayey soils. Peaty soils are soils containing less than 50% organic matter.
Peat is soil that contains more than 50% organic matter.
Silt is a highly porous water-saturated sediment formed as a result of microbiological processes in water bodies. Soil porosity can reach 60%.
Sapropel is a water-saturated sludge containing more than 10% organic matter. Its porosity is up to 75%

All of the above soils have high humidity - up to 80%, and low bearing capacity for loads from the weight of the house. For example, the design load resistance for sludge is 0.4-0.6 kg/cm2, for peaty sandy soils - 0.4-2.5 kg / cm 2.

Waterlogged areas may be of natural or artificial origin. Waterlogging can be the result of human activities. Sometimes waterlogging occurs after the construction of a house on the site.

Artificial swamping of the site lead to:

Raising the general level of the soil during the construction of roads in the village and during construction in neighboring areas. As a result, the natural flow of water from the areas below is disturbed.
Construction of fences on a solid strip foundation without water channels.
Lack of organized storm water runoff on the site and on the territory of the village.

The process of artificial bogging usually takes several years.

Due to high humidity and high groundwater levels soils in wetlands are highly heaving.

A house built on weak and heaving soils is exposed to an increased risk of destruction, as a result of significant settlement and uneven soil deformations.

Even on a hard foundation a house can gradually sink into a swamp over the years. Under the weight of the house, water is gradually squeezed out of the pores of the soil, the soil under the house is compacted and the house gradually settles every year.

How to make weak ground stronger

The layer of weak swampy soil in different areas has a different thickness. For example, in one area, a layer of weak soil may not be thicker than 1 meter. On the other - more than 10 meters. Under the layer of swampy soil there is always a layer of low-compressibility soil with “usual” properties for construction.

The bearing properties of weak soil can be improved in the following ways:

Vytorfovka - replacing marshy soil with a pillow of non-porous soil. The replacement is carried out under the sole of the foundation for the entire thickness of the marshy soil layer or partially.
The device of the foundation on an embankment of non-porous soil.
Soil compaction under the base of the foundation.

Building regulations prohibit the support of the soles of the foundation of the house directly on weak ground. Therefore, pillows and embankments are a necessary element in the design of the foundation on soft soils.

Features of the design of the house on soft soils

When building on swampy soils, constructive solutions are used to reduce soil settlement by reducing the specific pressure of the house on the ground. To reduce the sensitivity of the house box to uneven deformations, the rigidity or flexibility of the building's load-bearing frame is increased.

To reduce the specific pressure of the house on soft ground and increase the rigidity or flexibility of the building frame, the following design measures are used:

They increase the area of support of the foundation on the ground through the use of a foundation - a slab or a strip foundation with a broadening of the sole.
They increase the spatial rigidity of the foundation due to the installation of a monolithic reinforced concrete foundation. (Prefabricated strip foundations made of blocks or masonry materials are not used.) They increase the rigidity of the slab foundation by installing stiffeners or making the foundation-plinth of increased height. Additionally, a monolithic reinforced concrete floor is arranged, rigidly connected to a monolithic basement-foundation.
The spatial rigidity of the building frame is increased by arranging monolithic reinforced concrete belts at the level of floors overlapping and reinforcing the masonry of stone walls.
Pile foundations are used with support on the underlying low-compressible soil layer.
On weak soils, it is advantageous to build houses from light and flexible building structures - logs, timber, frame. The cost of building foundations for such houses is much less than for fragile houses made of stone materials.

The task of choosing the design of the foundation and the design features of the house box is to ensure that determine the most economical option for specific construction conditions.

For example, which is more profitable- to excavate the entire depth of the swampy soil and strip foundation or install a pile foundation or pour a foundation slab on an embankment? Which house will be cheaper to build on soft soils- with walls made of flexible glued laminated timber or brittle aerated concrete? In each case, the answer to this question will be different. The correct answer can only be obtained from specialists - designers.

Managers of construction companies usually try to impose a foundation option on the developer, based on their interests, the more expensive the better. Or they can, in order to keep the customer, offer a very cheap option, agreeing to which, the developer will later bitterly regret.

The figure below shows the arrangement of an artificial soil base and a slab foundation for a stone house on soft marshy soil.

Slab foundation for a one-story house with cellular concrete walls with brick cladding. 1 - thickness of weak marshy soil - 10 m; 2 - sand cushion; 3 - embankment; 4 - planning filling; 5 - base plate; 6 - base; 7 - waterproofing; 8 - blind area; 9 - groundwater level - 0.4 m from the surface.

Consider the measures taken by the designers of the foundation, allowing you to build a house on weak marshy soil.

To improve the building properties of the soil at the base of the foundation:

Partial excavation was completed - the vegetative layer of soil was cut off in a section with a thickness of 300 mm. (slightly above the groundwater level). In the resulting recess, a sand and gravel pad is arranged, item 2 in the figure.
An embankment, pos.3, was made from non-porous soil. The soil in the embankment is laid with layer-by-layer compaction. Under the weight of bulk soil, the underlying layers of weak soil are compacted and settled. It is recommended to start building a house 6-12 months after filling to allow time for settlement to stabilize.

After the device of the slab foundation, the planning filling of the soil is additionally carried out, pos.4. Planning filling is carried out with any soil.

Building a house on an embankment contributes to the general rise in the surface level of the site, ensures the removal of melt and rainwater from the house and from the site.

The height of the embankment, pos. 3, can be reduced by increasing the thickness of the sand cushion, pos. 2, so that the total thickness of the fill soil of the cushion and the embankment remains unchanged. It should be borne in mind that it is quite problematic to pour and compact the cushion soil in water, below the groundwater level.

Constructive solutions for building a foundation for a house in a swamp:

To reduce the pressure of the house on the ground, a slab foundation was used - a monolithic reinforced concrete slab under the entire area of \u200b\u200bthe house, item 5 in the figure. Moreover, the dimensions of the foundation slab are increased and go beyond the walls by 300 mm. from each side.
The spatial rigidity of the foundation is increased by installing a monolithic reinforced concrete plinth, pos.6, connected with reinforcement outlets to the foundation slab.
A monolithic reinforced concrete floor at the top level of the basement can further increase the rigidity of the foundation. The single structure of the basement space box made of monolithic reinforced concrete is a fairly rigid foundation for a stone house.
At the house with the walls of their aerated concrete, and arrange a monolithic reinforced concrete belt at the level of the floors.

The foundation structure shown in the figure was designed for rather difficult soil conditions: the soil is water-saturated silt with a thickness of 10 m., high groundwater level - 40 cm. from the surface.

For more favorable soil conditions, the volume of pillows and embankments, as well as monolithic reinforced concrete at the base of the house, can be significantly reduced.

Increasingly popular with private developers variant of the slab foundation - insulated Swedish slab. In this option, a heater is placed under the monolithic foundation slab, and the stiffeners are directed downward into the ground. The foundation slab serves as the base for the walls and the base for the floor of the first floor. Some disadvantage of this foundation design is the low base. In conditions of a significant thickness of snow cover in most climatic zones of Russia, increases the risk of wetting the bottom of the wall of the house.

The reinforcing cage for reinforcing the foundation slab of a private house usually consists of upper and lower reinforcing meshes and vertical ties between them. The number of reinforcement bars and their diameter are determined by calculation.

In the case of the construction of heavy two-three-story brick houses in difficult soil conditions, it may be more profitable to build a foundation on driven piles.

On weak soils with a layer thickness of less than 3-5 m. Consideration should be given to the feasibility of building a house on bored or screw piles supported by an underlying low-compressibility soil layer.

Shallow strip foundation for a house in a swamp

Houses with frame walls, as well as with walls made of logs and timber, are more flexible - they can withstand much greater deformations than stone houses. Such houses in the swamp can be built on shallow or shallow strip foundations.

Shallow strip foundation for a one-story house with frame or wooden walls. 1 - thickness of weak marshy soil - 10 m.; 2 - sand - gravel (crushed stone) pillow; 3 - tape monolithic reinforced concrete foundation; 4 - planning embankment; 5 - blind area; 6 - waterproofing; 7 - groundwater level - 0.4 m. from the ground surface.

The shallow-depth monolithic strip foundation under the outer and inner walls, item 3, is a single spatially rigid frame. In order to increase rigidity, the height of the foundation tape, combined with the plinth, has been increased. The wide sole of the foundation is located at the level of the soil surface on a sand and gravel pad.

Strip foundation reinforcement scheme

For the foundation shown in the figure above, it is enough to make reinforcing meshes in the upper and lower chords from three longitudinal rods with a diameter of 12 mm, class A-III. Reinforcing bars in the mesh are connected with auxiliary connections made of wire Vr with a diameter of 6 mm.

The upper and lower grids are connected by vertical rods of transverse reinforcement with a diameter of 8-10 mm, class A-III. Concrete protective layer for foundation reinforcement at least 5 cm.

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