What is the soil replacement procedure or. Replacement, replacement of weak soils under the base

Throughout Russia, soils with a high content of clay are very widespread. In winter, when the temperature drops to below zero, the volume of liquid in the ground increases and the soil “swells”. Swelling damage and the rate at which a house collapses depends on the foundation and weather conditions. In the best case, when you arrive next year at a new dacha, you will not be able to open the door due to the fact that the structure is seriously deformed, in the worst case, you will find serious structural violations. The only way to avoid the action of swelling is the correct laying of the foundation, which can resist increased loads for a long time.

Why and how swelling occurs

With the wrong laying or the wrong type of foundation, swelling begins to destroy the building quite quickly. The milder the weather conditions, the slower the force of compression and expansion of the soil will act; in highly heaving soil, the foundation will have to withstand vertical changes in the ground level up to 35 cm and a horizontal load of up to 5 tons per 1 m2. Soil susceptibility to swelling is directly affected by several factors:

• soil composition Clay soils (clays, loams, sandy loams) are most prone to heaving, and sandy soils are to a lesser extent. The higher the clay content in the soil, the greater the frost heave will be. Clay has many closed pores that retain moisture well, sand, on the contrary, practically does not retain moisture;
• Soil saturation with water is also important. For this reason, clayey but dry soils are less prone to heaving than mixed but wet ones. The moisture content in the soil is determined by the level of groundwater for the period of freezing of the earth;
• the temperature regime affects the depth and duration of the soil freezing period.

All the negative phenomena associated with temperature fluctuations affect a limited layer of soil to the level of freezing. It is easy to determine this level (GPG - the depth of soil freezing) using a special map, you can see one of them. You can also refer to SNiP, which contains a table of normative soil freezing depths, which determines the minimum foundation laying depth. It should be borne in mind that in the maps and the table it is given very approximately and with a margin of 20-40%, for soil not covered with snow and at the lowest average temperatures. The actual freezing depth is much less, especially if the house is heated during the cold season. Therefore, there is no particular danger in deepening the foundation to a slightly smaller depth.

Types of foundations for heaving soil

Therefore, the swelling problem has several basic solutions:

1. Deepening the foundation below the GPG gives the structure additional strength. But it should be borne in mind that a buried pile-type foundation resists vertical loads well, but with significant horizontal loads it can show itself much worse. The recessed foundation is suitable for the construction of both small and heavy capital buildings. For the foundation, either screw piles are used, or reinforced concrete poured in place (the latter is a more effective solution), waterproofing for the reinforced concrete pile is a layer of roofing material, which is laid before pouring into the well drilled for the pile. For small buildings (arbors, wooden outbuildings), a simple foundation based on brick pillars is suitable - this is the most economical option;

   

2. It is possible to replace the desired volume of soil with non-swelling coarse sand or similar material. To replace the soil, a foundation pit is dug with a depth below the GPG, its bottom is covered with compacted sand or sand gravel, then with a layer of waterproofing, on top of which the soil suitable for the foundation is already filled up. Replacing the soil is more expensive than laying a deep foundation, requires a large amount of earthwork, but allows you to finally solve the problem of heaving;

   

3. Light structures on heaving soil are often built on a reinforced slab or shallow strip foundation (a more complex and expensive structure in which reinforced concrete is laid along the contour of the building and surrounded by sand and a waterproof coating). This type of shallow foundation has a significant plus - the load is very efficiently distributed throughout the entire structure of the building, minus - a shallow foundation is suitable only for a light wooden house;

   

4. Another option is not to let the foundation freeze along with the soil. To do this, it can be insulated by creating a sufficient layer of thermal insulation: a layer of polyurethane foam, expanded polystyrene or expanded clay is laid around the perimeter of the building. The insulating layer cake consists of compacted sand used as a substrate, the actual insulation and waterproofing layer. The thickness of the insulation must be equal to HGG;
5. If you supplement the measures for warming the foundation with the creation of a drainage system, you can significantly reduce the level of groundwater and soil freezing. A drainage ditch laid along the perimeter of the foundation at the depth of its laying will collect moisture from the soil and remove it below. The second option for a drainage system is drainage wells drilled along the perimeter of the house at a distance of 2-3 meters.

   

Of the above solutions, the most economical is the insulation of the foundation and the installation of a drainage system, the most expensive and effective is the replacement of the soil under the foundation. You can carry out a drainage system and insulate the foundation yourself, but in this case it is necessary to carefully study the thermal insulation properties of the selected material and correctly place the waterproofing layer.

It is very difficult to resist swelling of the soil in some regions of the country; deepening and reinforcing the foundation is indispensable. There is no universal and inexpensive solution, but modern technologies offer many solutions to the problem of building deformation due to heaving: from effective insulating materials to complex strip foundation designs. The optimal solution in each case will have to be chosen independently, comparing the material and time costs in specific conditions.

Water in the ground is a dangerous phenomenon for the foundation. You need to start fighting it at the design stage of the house. First of all, it is worth conducting geological studies that will determine the level of moisture location. Which foundation is suitable for a high groundwater level depends on a certain mark.

Geological research in private construction is carried out manually. To do this, dig holes 50 cm deep below the estimated foundation mark or use the manual drilling method to the same depth. It is important that there is no accumulation of moisture at a distance of half a meter from the sole of the building. Tests are recommended to be carried out in the spring (when the water level is the highest) in the lowlands of the site.

The foundation at high groundwater becomes a structure that is constantly exposed to negative influences. Moisture in the soil leads to such a phenomenon as frost heaving - an increase in soil in volume under the outer walls of a building. At the same time, the central part of the house remains in the same position. Uneven deformations are the main cause of cracks in the walls.

Freezing will become a problem for the foundation material. Most often, the structure is made of concrete. Moisture enters the pores of the underground part of the building and freezes there. Water expands when frozen. This property distinguishes it from any other substance on the planet. In this case, the pressure inside the concrete structure increases. In the spring, the structure thaws - the pressure decreases. Such constant loosening of internal bonds in concrete leads to its destruction.

Groundwater at the site can corrode materials if it contains alkalis or acids. This phenomenon is especially dangerous for concrete. Reinforcement during pouring is protected by a layer of concrete 2-3 cm thick, which prevents its damage.

Location of GWT at a distance of 3 m or more from the surface

This situation is the most favorable. In this scenario, it is possible to build buildings with a basement without any special measures. A recessed strip foundation is used as a supporting part. When clay soils (clay, loam, sandy loam) occur on the site, a number of measures are required to prevent frost heaving with a possible rise in moisture in the spring and with heavy rainfall:

• support of the sole below the freezing depth (determined separately for each settlement);
• vertical waterproofing of basement walls with bitumen or gluing materials (roofing material, linokr, hydroisol);
• backfilling under the sole of the foundation of sand (medium or coarse fraction), crushed stone or gravel 30-50 cm thick;
• drainage device at the level of the sole.

Location of GWT at a distance of 1.5 m or more

As a foundation at a high level of groundwater, it is recommended to use an unburied tape or slab. The strip base is suitable for construction on solid soils. For fragile soils, a slab option is used. For a small building, it is allowed to use poles. The depth of laying the supporting part of the house is assigned within 70-100 cm.

When erecting a shallow strip foundation on clay soils, it is necessary to provide protection against frost heaving. To do this, use a set of measures:

• laying drainage at the level of the sole along the perimeter of the house;
• bedding from non-porous materials (sand, crushed stone, gravel);
• insulation of the outer surface of the tape and insulated blind area.

If it is necessary to build a basement and a deep foundation, it is required to provide reliable waterproofing. To keep the room dry, the following measures are provided:

• external waterproofing (for example, roll material using a protective screen);
• internal waterproofing (plaster, penetrating);
• use for pouring basement walls of concrete with low moisture permeability (not lower than W8).

Also, a mandatory measure will be a drainage system around the perimeter of the building and storm sewers to drain rain and melt water.

Location of GWT at a distance of 0.5 m or more

In this case, the device of the basement is a very costly undertaking. It is strongly recommended to refuse it. When the water horizon occurs at a distance of 0.5 m from the surface, non-buried types of foundations are used:

• columnar;
• tape;
• slab.

The first option is practically not used due to the low bearing capacity. Unburied tape is suitable only for small outbuildings made of lightweight materials. This includes wood and frame structures. It is better to use a T-section of the foundation (with a broadening at the bottom), since it has a greater bearing capacity than a rectangular one.

If you need to build a large house, choose a stove. Its thickness and reinforcement are assigned depending on the number of storeys of the building and the material from which the walls are made (wood, lightweight concrete, brick). In this case, you will have to take care of the insulation of the structure, since the foundation is not protected from the destructive effects of cold. A good solution would be an insulated Swedish plate (USHP), which is protected by extruded polystyrene foam or ordinary foam. Penoplex is more expensive than polystyrene, but it will also provide waterproofing for the structure.

The technology assumes the presence of three ways of laying thermal insulation at the same time:

• under the stove;
• vertical along the perimeter of the plate;
• insulated blind area.

To prevent frost heaving and increase the bearing capacity of the base, soil is replaced. To do this, use medium or coarse sand, gravel or crushed stone. You can mix materials (sand-gravel mixture). On average, the thickness of the pillow is assigned 30-50 cm. But if the soil in the area is weak, then the backfill is laid until it stops going into the ground and displaces excess moisture.

GWL location closer than 0.5 m

In this situation, the use of non-buried foundations is impossible, since the condition is not met: the groundwater level should be located 50 cm below the foundation support. Piles will be the only solution. They differ in manufacturing technology, immersion method and material.

The most commonly used reinforced concrete and metal piles. The most popular option was steel screw elements. They allow you to perform work even in a heavily swampy area without additional measures. This type of foundation is classified as inexpensive and least labor-intensive, but it is applicable only for a frame or wooden house: metal piles do not have a large bearing capacity. The most common screw pile diameter is 108 mm. Step and depth are selected depending on the load.

Reinforced concrete elements in private construction are made by the bored method. One of the subspecies of such piles was elements using TISE technology. They are especially relevant in the prevention of frost heaving, because they have a broadening at the bottom and prevent pulling out.

The bored type of base is suitable for buildings made of any materials. The main disadvantage is the complexity of manufacturing. Such a foundation, with a high GWL, requires temporary dewatering for the construction period, which significantly increases financial and labor costs.

To connect individual supports into a single structure, a grillage is mounted along the edge of the piles. He might be:

• wooden (wooden or frame house);
• reinforced concrete;
• metallic.

The last two options are mainly used in the construction of brick and concrete buildings.

The foundation with a high level of groundwater is one of the most complex and critical structures.

Such a foundation of the house must be built, taking into account a wide variety of factors, each of which must meet all the requirements associated with the risk of flooding and premature destruction of the building.

Accordingly, it is important to correctly determine the level of soil freezing, choose the most suitable base design and ensure that an effective drainage system is in place.

Determining the level of groundwater and possible concerns

Ground water level

The foundation device at a high level of groundwater must be stable and reliable. What is the degree of threat of subsidence and destruction of the building, find out long before the start of construction work. To this end, in spring or autumn (at a time when the amount of moisture contained in the soil reaches its maximum level) at the place where, in accordance with the construction plan, the basement will be equipped, a hole should be dug at least 3 m deep.

Dig a hole at least 3 m deep

To obtain accurate data, you will need to reliably protect the pit from weather precipitation. After a few weeks, a certain amount of water will appear and settle at the bottom. Perhaps the bottom will remain dry, and then the foundation does not require additional protection.

If the water is at a distance above 2 m from the surface, it is necessary not only to calculate the depth at which the foundation will be built, but also to choose the right structure.

What should be the foundation with high groundwater, experts can say after geological surveys.

Piles will raise the level of the house to a safe height

Among the existing foundation structures on high-level groundwater, pile structures are especially popular and trusted by consumers.

Their arrangement will help to ensure high-quality and reliable protection of the foundation of the house from the negative impact of groundwater:

• basement flooding;
• destruction of concrete structures;
• the emergence and development of fungus and mold;
• violation of the integrity of the foundation itself during freezing in the cold season.

With a high GWL, the walls of the pit can swim

In addition, a high GWL causes the walls of the pit to sink and a sharp decrease in the bearing capacity of the soil. This will require additional work on the arrangement of an effective drainage system, including wells and water collectors.

The process of leaching minerals from the soil is recognized as the most dangerous, which significantly worsens the strength characteristics of the soil and leads to a change in its structure. The installation of the foundation in such conditions has a number of limitations. The calculation of the depth at which the supporting structure will be poured is carried out taking into account the qualitative features of the soil:

• loams;
• sandy;
• clay;
• mixed.

The level of heaving and the depth of soil freezing depend on this. If the freezing depth is less than the GWL, then when planning, there is no need to make an amendment to the characteristics of the soil.

The calculation is carried out adjusted for the type of soil and the possible subsidence of weak soils.

The data obtained most often force us to abandon the construction of a tape structure, since the work associated with this will be very laborious and require significant material costs.

A variety of foundations and the right choice of the desired design

The slab foundation is suitable for clay soils with high GWL in a shallow version

What foundations are needed for houses, if groundwater is close, is chosen depending on the various features of the site itself on which construction is being carried out. The foundation on the water is a structure that should ensure the stability of the building, its durability and reliability. To do this, it is necessary to take into account both the quality of the soil and the upcoming loads coming from the building.

Building a foundation on clay soils with a high level of groundwater implies the construction of any kind of foundation:

• tape, the trenches of which are very deep;
• pile;
• slab (shallow).

The tape base requires the creation of a monolithic reinforced concrete structure located under the external and internal load-bearing walls.

The depth of the trench must exceed the freezing height

First of all, markings are made on the site, in accordance with which they dig trenches for the strip foundation. Their depth should exceed the freezing height. The calculation is carried out adjusted for the peculiarities of weather conditions (temperatures in winter) and soil.

If groundwater is close, and construction is to be carried out on clay, the strip foundation will perfectly replace the "floating" monolithic slab. The weight of the building is evenly distributed over the entire surface of the slab, which is laid on a sand and gravel pad.

Before you make such a foundation, you will need to remove the soil from the entire territory of the future foundation. The pit is dug with a depth exceeding the thickness of the slab by 50 cm. The calculation is based on the freezing depth of the soil.

The pile foundation of the house is the best option for creating a high-quality reliable foundation on clay soils.

By changing the parameters of the piles, it is possible to achieve the installation of supports on solid rocks that are not subject to destruction under the influence of groundwater.

To carry out work on a site with a high GWL, it is necessary to calculate the load on each individual pile.

Construction of various types of foundations

If groundwater is close at the foundation site, then before proceeding with the construction of the slab base, it will be necessary to prepare ditches around the entire perimeter of the future building. It is better if it is a trench 20-30 cm wide and at least 50 cm high (depth). The ditches will be filled with rain or melt water, and thus drainage will be carried out. For more information on the preferred type of foundation, see this video:

To protect the walls of the foundation, treat them with waterproofing mastics

The “floating” slab does not lie on clay soil, but on a cushion created from sand and gravel. This type of foundation must be poured, having built it on bulk soil. Before pouring, a drainage system is installed, laying drains at a slope of at least 5 cm per meter of pipe. To protect the slab, it is necessary to send the inner surface of the base with waterproofing materials. Most often, roofing material is used, laying the sheets with an overlap of 10-15 cm wide. Fasteners are made using bitumen.

A reinforcing frame is laid on the waterproofing and poured with concrete, the filler for which is fine gravel. It is better to pour the entire base in one day.

The strip foundation requires careful preparation of the trenches of the excavation. They must be deep and wide enough to exceed the freezing depth of the ground and allow high-quality assembly of the formwork structure.

A monolithic tape is poured, taking care of the correct backfilling of its bottom, high-quality tamping and the arrangement of waterproofing. A frame connected from reinforcing bars of various sections is installed inside the formwork. Concrete is poured in layers with obligatory tamping of each layer. Useful tips when building a house on soil with a high GWL, see this video:

The pile grillage foundation is recognized as the most reliable in the construction of buildings in areas with a high groundwater level. When making such a foundation, it is important to follow the soil indicators, depending on which the size of each of the piles used is determined. Piles use:

• screw;
• bored;
• driven.

Screw structures are mounted independently without the involvement of heavy construction equipment. After installing all the piles, a grillage is assembled on them or a beam is laid, which is necessary in order to tie the entire structure together.

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Maksimus.81 ->

we will order geodesy in the near future .. they advised pile, but it seems expensive ... but if you give an example on the well - then the first ring is earth, from 2 to 4 clay, and from 5 earth stones and water went - we were not even advised to pour anything there - the water is clean ... now there is a 6 * 6 country house on the site, under it there is a cellar - full of water in the spring, it is not very deep ... we want to hire workers under the control of our own person, who himself can from the foundation to the roof ... it’s just hard for one. - the prices are aching - it doesn’t fit in my head ... the parameters of the house are already ready to be reduced to 9.0 * 9.0, it will still be individual ... but you don’t know about heat blocks - better than gas-foam blocks?

High groundwater: columnar foundation

The construction of the foundation at a high level of groundwater is the most important issue that arises during the construction of the underground part of the building. It requires the right answer, on which not only the comfort of operation, but also the durability of the building will depend.

There are a lot of criteria that must be taken into account when choosing the type of foundation yourself, and we will try to describe them in detail. The video in this article on the topic: “High groundwater level: what kind of foundation to make?” will also help you cope with this task.

What to consider when choosing a foundation

The concept of "high groundwater level" can also be relative. If the water is two meters from the surface of the earth, and you want to build a house with a basement, then this is already a hindrance to construction, and a real threat of flooding during operation.

• At the same time, the basement can be buried only halfway, or even limited to the ground floor. For the construction of other buildings: a summer kitchen, a temporary house, a barn, a garage, such a water level is not at all a hindrance, if, again, they do not have a basement.
• But there are situations when the water is very close to the surface, and then any construction becomes problematic. Of course, there are various technologies for land reclamation, dewatering and soil stabilization. Another question: "What will be the price of the object?".

Deeply buried strip foundation with a high level of groundwater

• In order not to come to such a sad result, which you see in the photo above, do not rush to purchase building materials and start earthworks. First you need to correctly assess the hydrogeological situation on the site.

If you are unable to do this on your own, seek the advice of an appropriate specialist.

This will help you take the right step in relation to the foundation, and save you from regrets about wasted funds. And they can turn out to be considerable when it comes not to a bathhouse or a garage, but to a house.

UPG and UGV marks

So, the choice of foundation at a high level of groundwater determines the cost of the structure. The right approach will avoid unnecessary investments, including labor costs.

Therefore, first collect all the necessary information about your site, and only then decide what and how you will build:

• It is not difficult to find out the GWL level, on our website there is more than one instruction on this topic (read How to find out the groundwater level). As for the level of soil freezing (STF), it is different in each region.
• Just note that within the same area, these numbers may vary, depending on the type of soil. Clay soils freeze the least. Then come fine sands, then coarse sands and sandy loams. On stony soils, the level of freezing is the highest.
• The GWL and GWP indicators must be compared, and if it turns out that the water lies above the freezing level, then the soil is also subject to frost heaving. This is always fraught with consequences, and in the example presented, you can see how this can end. If there is a danger of heaving of the soil, you need to choose such a variant of the foundation device, which will be in contact with it as little as possible.

The impact of frost heaving of the soil on the foundation

• A strip foundation in such a situation, in general, can emerge. The best solution to this problem can be a house on stilts - this is not the cheapest, but the most reliable option (see Groundwater close: how to build a house on stilts).
  It is clear that for a small building such as a barn, no one will hammer concrete piles. There is a special technology for this case: Chise foundations, and we will talk about them in a separate chapter.
• In the southern regions, where there is practically no frost, houses are often built on a shallow or ground strip foundation, making a thick drainage layer of crushed stone and sand under its sole. But, in some areas there are no quarries nearby where they could be purchased at a reasonable price.

Delivery of a sand-gravel mixture from afar greatly increases the cost of the zero cycle, especially if the thickness of the backfill has to be increased. A columnar foundation is much more economical, and building it with your own hands is not so difficult.

There is no single recipe for all occasions, as you understand. Our task is to tell about the possible options, and yours is to make the right choice.

Foundation tape shallow

Say what you like, but the strip foundation in private construction firmly holds the palm. There are not so many areas where groundwater comes directly to the surface, and if its level is at least at a depth of 1-1.5 m, then it is quite possible to make a shallow foundation, or simply ground.

• This option is not suitable for any building - both its number of storeys and the materials used in construction matter. After all, there is a difference: a one-story house is being built from cellular concrete, with a wooden beam ceiling, or a two-three-story brick mansion, with concrete ceilings and stone cladding. The loads here are completely incomparable, and the foundation must be designed for them.

Ground strip foundation at high groundwater

• In terms of cost, a shallow foundation is the cheapest. This is facilitated by a small amount of earthworks, the absence of a basement, which means savings on wall material. In order to build a bath or makeshift - this is generally the best option.
• For a house, even a one-story one, it is still better to make a buried, albeit slightly, foundation - this is much more reliable. Sometimes it even comes out cheaper, since there is no need for formwork. But this is only in the case when you do not have to deal with loose soil. For him, the best option is driven piles.
• If the soil is sufficiently dense, the trenches in it turn out to be even, with good geometry, and their walls perfectly serve as formwork when pouring foundations. Just so that the cement milk from the concrete does not go into the soil, the recesses are covered with two layers of plastic film, gluing the joints with adhesive tape.

Small deepening of the strip foundation

• This film serves as an additional waterproofing of the structure, but before laying it, the bottom of the trench must be covered with a layer of sand and gravel mixture by 10-15 cm.

The height and width of the foundation tape must be determined by calculation. This takes into account the type of soil, the likelihood of its heaving, the expected loads, the climatic conditions of the area, and, of course, the landscape of the site allotted for construction.

Formwork types

In the case of the presence of slopes or bends in the relief on the site, it is not recommended to pour the foundation without formwork. How can you get out of this situation and avoid unwanted earthworks, because it is simply impossible to dismantle the formwork in a narrow trench?

In this case, there are various options for fixed formwork: from flat slate to foam panels.

Arrangement of non-removable foam formwork

• If we proceed not from considerations of economy, but from the strength of the structure, blocks of expanded clay concrete or polystyrene concrete can also serve as a material for fixed formwork. A brick is also perfect: at least full-bodied, at least hollow, at least used.
• These materials are laid in a trench in the form of two parallel walls, between which reinforcement is installed and concrete is poured. If blocks or bricks have through voids, they are laid flat so that concrete can fill the voids.
• The walls of houses are often erected in the same way, only they are reinforced in a different way, and instead of concrete, the cavities are filled with loose or foam insulation. This method is called well masonry.
• It is most convenient to use it in a narrow trench, since its walls do not allow bricks or blocks to move. When such a foundation is made in a spacious pit, formwork also has to be placed under it.

Scheme of the device of a shallow foundation

The depth of the trench under the foundation of a small country house or other building can be, for example, 40 cm. In the case of a residential building, the height of the support tape must be at least 70 cm, and if the groundwater level does not allow it to be buried completely, the upper half of the foundation may well rise above the surface.

Pile foundation TISE

In order to build a massive building on problematic soil, there is no better option than a pile foundation. Using driven or screw piles is an expensive pleasure.

It requires special equipment and a team of specialists, because it is simply impossible to drive piles and cut their heads at one mark on their own.

• The foundation of TISE with a high level of groundwater is the most preferred option. It will almost double the cost of the foundation part of the building, including through the use of its own forces.
  This technology got its name from the name of the tool used for excavation. That's what you see in the photo.

Manual drilling tool TISE

• TISE is a drilling tool, very similar to a garden drill. The difference in their design is only one detail. It is a plow on a rotating arm, which allows you to expand the bottom of the drilled well. Thus, the base of the pile expands, increasing the footprint.
• So, you don’t need to drive a pile into the site - in this case, everything is done manually. In terms of its structure, the TISE foundation does not differ much from a conventional pile foundation. It also looks like a pile field, with a grillage crowning it, not touching the ground.
• Naturally, this design should also be calculated for loads. The spherical expansion of the supporting part of the piles improves the bearing capacity of the foundation as a whole, which makes it possible to use this option not only for the construction of relatively light frame-panel buildings, but also for brick and stone houses.

Pile foundation at high groundwater level

• It is this expanded part of the foundation pillar that provides it with unshakable strength when the heaving forces of the soil push it to the surface. Thanks to such stability, the pile field can stand in the winter without load, which in no case should be allowed when constructing a strip foundation.

A building placed on a pile foundation is not subject to seasonal shrinkage at all. For a wooden house, this is not so important, since wood works well in bending.

But stone and brick walls with frosty heaving of the soil can simply crack from floor to ceiling. And this becomes a problem - and the supporting structures need to be repaired, and the finish will have to be made new.

Some technology details

In the process of designing a pile field, depending on the expected loads, the dimensions of the piles and their locations are calculated.

After all, you need to know their diameter and length, the distance between them, the location option, the place of reinforcement:

• On average, the step between piles is from 1.5 to 2m. The depth of their laying is also within the same digital limits, but it should not be less than the UPG mark.
  The essence of their device is as follows: a spatial frame of four to five D-12 mm reinforcement rods connected with steel wire is installed in the drilled wells.

Reinforcement of the TISE foundation

• Then a cement-sand mixture is poured into the well, with a ratio of dry components of 1:4. If this is a small building such as a barn or garage, you can even save a little by putting cement and sand 1: 5. But when a house is being built, it is better, nevertheless, not to reduce the amount of cement, and even make a ratio of 1:3.
• Simply, for pouring it is better to use not Portland cement, but gypsum alumina cement. When moistened, it spontaneously expands, filling the smallest pores in the walls of the well.
  Such cement allows to reduce the consumption of the solution, which will not be strongly absorbed into the soil - it is it that drillers use for plugging wells.
• If you work with ordinary cement, you need to use a formwork in the form of a metal pipe, which can be removed after the concrete has hardened, or a piece of roofing material rolled into a tube. You can also take asbestos-cement pipes, which will play the role of fixed formwork, which you can see in the photo below.

Formwork for monolithic piles and grillage

• The solution poured into the well is carefully compacted by baying, or using a deep vibrator. With a high location of groundwater, there are certain difficulties in concreting.
  And here, the faster the well is filled with a solution, the less time the water has to seep into it. Otherwise, you will have to pump out the water with a pump.

For the convenience of work, wells are drilled in 4-5 pieces. At the same time they are reinforced and then concreted.

First, the expanded segments of prepared wells are filled and compacted, and then their trunks. As for the concreting of the grillage, this technology is similar to the process of pouring a strip foundation.

Before starting the construction of the foundation of the house, such an operation as checking the bearing capacity of the soil must be carried out without fail. Research is carried out in a special laboratory. In the event that the existence of a risk of collapse of the building during its construction in this particular place is revealed, measures can be taken to strengthen or replace soils.

Classification

All soils are divided into several main types:

• Rocky. They are a solid rock mass. They do not absorb moisture, do not sag and are considered non-porous. The foundation on such grounds is practically not deepened. Rocky soils also include coarse-grained soils consisting of large ones. In the event that stones are mixed with clay soil, the soil is considered weakly heaving, if with sandy soil it is non-rocky.
• Bulk. Soils with disturbed natural layering structure. In other words, artificially poured. Buildings on a similar basis can be built, but first you must perform a procedure such as soil compaction.
• Clayey. They consist of very small particles (no more than 0.01 mm), absorb water very well and are considered heaving. Houses sink on such soils much more strongly than on rocky and sandy ones. All are classified into loams, sandy loams and clays. These include loess.
• Sandy. They consist of large sand particles (up to 5 mm). Such soils are compressed very weakly, but quickly. Therefore, houses built on them settle down to a shallow depth. Sandy soils are classified according to particle size. Gravel sands (particles from 0.25 to 5 mm) are considered the best bases.
• Quicksand. Dusty soils saturated with water. Most often found in wetlands. For the construction of buildings are considered unsuitable.

Such a classification by type is carried out in accordance with GOST. Soils are examined in laboratory conditions with the determination of physical and mechanical characteristics. These surveys are the basis for calculating the capacity of foundations for buildings. According to GOST 25100-95, all soils are divided into rocky and non-rocky, subsidence and non-subsidence, saline and non-saline.

Main physical characteristics

When conducting laboratory studies, the following soil parameters are determined:

• Humidity.
• Porosity.
• Plastic.
• Density.
• Particle Density.
• Deformation modulus.
• Shear resistance.
• Friction angle of particles.

Knowing the density of particles, it is possible to determine such an indicator as the specific gravity of the soil. It is calculated, first of all, to determine the mineralogical composition of the earth. The fact is that the more organic particles in the soil, the lower its bearing capacity.

What soils can be classified as weak

The procedure for conducting laboratory tests is also determined by GOST. Soils are examined using special equipment. The work is carried out only by trained specialists.

If, as a result of testing, it is revealed that the mechanical and physical characteristics of the soil do not allow the construction of structures and buildings on it without the risk of their collapse or violation of the integrity of the structure, the soil is recognized as weak. These for the most part include quicksand and bulk soil. Loose sandy, peaty and clayey soils with a high percentage of organic residues are also most often recognized as weak.

If the soil on the site is weak, the construction is usually transferred to another place with a better foundation. But sometimes this is not possible. For example, on a small private plot. In this case, a decision can be made to build a pile foundation with a laying depth of up to dense layers. But sometimes it seems more appropriate to replace or strengthen the soil. Both of these operations are quite expensive in terms of both financial and time costs.

Soil replacement: principle

The process can be done in two ways. The choice of method depends on the depth of dense layers. If it is small, weak soil with insufficient bearing capacity is simply removed. Next, a poorly compressible cushion of a mixture of sand and other similar materials is poured onto the dense base of the underlying layer. This method can only be used if the thickness of the soft soil layer on the site does not exceed two meters.

Sometimes it happens that dense soil is located very deep. In this case, the pillow can also be laid on a weak one. However, in this case, accurate calculations of its dimensions in the horizontal and vertical planes should be performed. The wider it is, the less will be the load on weak soil due to the distribution of pressure. Such pillows can be used when constructing foundations of all types.

When using such an artificial base, there is a risk of crushing the pillow with the weight of the building. In this case, it will simply begin to bulge into the thickness of the weak soil from all sides. The house itself will sag, and unevenly, which can lead to the destruction of its structural elements. In order to avoid this, sheet piling is installed around the perimeter of the pillow. Among other things, they prevent waterlogging of the sand and gravel mixture.

Is it possible to change the soil on the site yourself

The replacement of soils for the foundation should be carried out only with the preliminary conduct of appropriate studies and calculations. Doing this on your own, of course, will not work. Therefore, most likely, it will be necessary to invite specialists. However, when erecting not too expensive buildings, for example, household ones, this operation can be performed “by eye”. Although we still would not advise taking risks, but for general development, let's look at this procedure in more detail. So, the stages of work in this case are as follows:

• Excavation is carried out to a solid foundation.
• Medium-sized sand is poured into the trench to the level of the sole of the future foundation. Backfilling is done in layers of small thickness with ramming of each. The sand must be moistened with water before compaction. Tampering should be carried out as carefully as possible. There should be no inclusions in the sand itself, especially large ones. Sometimes soil-concrete mixtures and slags are used instead.

In the event that an artificial base is used under the foundation, it is also worth arranging. This will slightly increase the density of the soil surrounding the pillow and prevent it from being squeezed out to the sides.

Works on the creation of a drainage system

• A ditch is dug a meter from the building. Excavation is carried out below the depth of the foundation. Width - not less than 30 cm. The slope of the bottom of the trench should be at least 1 cm per 1 m of length.
• The bottom of the trench is rammed and covered with a five-centimeter layer of sand.
• Geotextiles are spread on the sand with the edges fixed on the moat stacks.
• Pour a ten-centimeter layer of gravel.
• Lay perforated drainage pipe.
• Cover it with gravel with a layer of 10 cm.
• Cover the "pie" with the ends of the geotextile and sew them together.
• They cover everything with soil, leaving manholes in the corners of the building.
• A receiver well is arranged at the end of the pipe. It is necessary to divert the drain at least five meters from the wall of the building.
• Gravel is poured at the bottom of the well and a plastic container with holes drilled in the bottom is placed there.
• Lead the pipe into the container.
• From above, the well is covered with boards and sprinkled with earth.

Of course, a drainage system should be installed on the building itself.

How is soil reinforcement done?

Since soil replacement is a rather laborious and costly operation, it is often replaced by the procedure of strengthening the base for the foundation. This can be applied in several different ways. One of the most common is soil compaction, which can be surface or deep. In the first case, a rammer in the form of a cone is used. It is lifted above the ground and dropped down from a certain height. This method is usually used to prepare bulk soils for construction.

Deep soil compaction is carried out using special piles. They are hammered into the ground and pulled out. The resulting pits are covered with dry sand or poured with soil concrete.

thermal method

The choice of soil reinforcement option depends, first of all, on its composition, the procedure for determining which is regulated by GOST. which was presented above, usually require strengthening only if they belong to a non-rock group.

One of the most common amplification methods is thermal. It is used for loess soils and allows strengthening to a depth of about 15 m. In this case, very hot air (600-800 degrees Celsius) is injected into the ground through pipes. Sometimes heat treatment of the soil is done in a different way. Wells are dug into the ground. Then combustible products are burned in them under pressure. Wells are hermetically sealed. After such treatment, the burnt soil acquires the properties of a ceramic body and loses its ability to absorb water and swell.

Cementation

Sandy soil (a photo of this variety is presented below) is strengthened in a slightly different way - cementation. In this case, pipes are clogged into it, through which cement-clay mortars or cement slurries are pumped. Sometimes this method is used to seal cracks and cavities in rocky soils.

Silicization of soils

On quicksand, dusty sandy and macroporous soils, the silicification method is more often used. To enhance this, a liquid glass solution is injected into the pipes and the injection can be done to a depth of more than 20 m. The liquid glass propagation radius often reaches one square meter. This is the most effective, but also the most expensive way to amplify. A small specific gravity of the soil, as already mentioned, indicates the content of organic particles in it. In some cases, such a composition can also be enhanced by silicification.

Comparison of the cost of replacement and soil reinforcement

Of course, the amplification operation will cost less than the complete replacement of the soil. For comparison, let's first calculate how much it will cost to create artificial gravel soil per 1 m 3. Selecting land from one cubic meter of area will cost about 7 USD. The cost of crushed stone is 10 USD. for 1 m 3. Thus, the replacement of weak soil will cost 7 c.u. for the recess plus 7 c.u. for moving gravel, plus 10 c.u. for the gravel. Total 24 c.u. Strengthening the soil costs 10-12 USD, which is two times cheaper.

From all this one can draw a simple conclusion. In the event that the soil on the site is weak, you should choose another place to build a house. In the absence of such an opportunity, it is necessary to consider the option of building a building on piles. Strengthening and replacing the soil is carried out only as a last resort. When determining the need for such a procedure, one should be guided by SNiP and GOST. Soils, the classification of which is also determined by the regulations, are strengthened by methods suitable for their specific composition.

The issue is especially typical for tired lands, cleansing the site for the foundation, and horticultural areas. The latter had the property of distributing “good” officials in those territories where it makes no sense to use agricultural enterprises due to the poverty of the soil. To understand all the features, you need to consider everything in order.

Replacement of fertile soil for a lawn

Creating a beautiful and even lawn is not easy, you need to bring the foundation into perfect condition. First, the earth is cleared of all flowers, roots, weeds, flower beds. Vegetation is removed in two ways:

- herbicides, which causes severe damage to the earth;

- bayonet shovel or excavator.

Both methods have their pros and cons. The optimal, but hard way, with a shovel. The thinnest layer should be removed, while capturing everything growing with roots. To turn the removed turf into, you need to leave it for three years in a compost pit. The following steps: adding a new clean fertile soil, leveling, feeding.

Removal of plant soil under the foundation

Before starting any construction, it is necessary to remove the turf for the following reasons:

- save on the purchase and delivery of soil;

- use the natural fertile layer;

- to prevent the process of decay of organic matter in the foundation and on the sides.

The boundaries and thickness of the layer to be removed are determined by the project, or rather by preliminary analysis.

1. The minimum depth is 10 cm, the maximum is 50 cm.

2. On a sandy base, plant soil lies to a depth of 5–10 cm.

3. On grassy areas - 12 cm.

4. On arable fields - 20 cm.

5. In forests up to 25 cm.

The process is carried out by heavy construction equipment: bulldozer or excavator, loader, dump truck or tractor for transportation. Infertile soil often has a yellowish color, fertile soil can be gray-brown-black. Cut layers are laid in piles of 1.5–3 meters.

Replacement of tired land in agricultural areas

The earth has a tendency to deplete. Therefore, it is necessary to carry out technical or biological reclamation. On large areas, the earth up to 10 cm is not removed. Special rules are established by GOST 17.4.3.02-85 "Requirements for the protection of the fertile soil layer during earthworks."

In the yard or in the garden, the owners try to constantly fertilize with organic matter, peat and minerals. If this process has not been carried out, then the soil has no fertile power. In order not to raise the site, you will have to remove a part and refresh it with new high-quality soil. In built-up spaces it is impossible to use heavy equipment, manual labor is used.

After the collapse of the Soviet Union, plots for dachas and gardens were massively distributed. Most of them are in unsuitable swampy areas or with a minimal amount of fertile layer. In these cases, it is necessary to clear the territory and purchase new fertile layers. If the fertile soil was removed during construction and did not bother to return it, then again you will have to import a new one.

Replacement of weak soils- an excellent solution for soil stabilization in the construction of roads, foundations, especially when it comes to large buildings or structures. Besidessoil replacementin demand in the arrangement of parking lots, parking lots, sports grounds, as well as storage areas.

Most often replacement and removal of soil by dump trucksproduced for washed soil or waterlogged soils. It is carried out through:

- excavation of the required amount of land;

- take it outside or use a neighbor for free raise the plot ;

- subsequent laying on the vacated place of good soil.

In what cases is it necessary substitution?

Before starting any serious construction work, it is very important to check the bearing capacity of the soil. This is necessary to minimize the likelihood of a structure or road collapsing. All soils are divided into several types: rocky, bulk, clay, sandy and quicksand. Each of them has different physical and chemical properties. soil replacement it is necessary if, according to the results of preliminary studies, it is revealed that the mechanical and physical properties of the soil can lead to collapse or violation of the integrity of the structure.

Traditionally replacement of weak soils- this is the excavation of loose sandy, clayey with a high content of organic matter and peaty rocks, followed by laying a dense layer.

Moscow and region in different areas has a different depth of occurrence of dense soils. That's why service replacement of weak layers is quite popular. It is very important that all work is carried out by highly qualified specialists. After all, each situation is unique, and the quality replacement of soil with construction sand or how a cheap alternative is this sand ground, like any earthwork, is a guarantee of the durability and strength of the future building.

What does it depend on price soil replacement services (soil replacement)?

Price for a soil replacement service depends on a number of factors. If the dense soil lies at a depth of no more than two meters, then it is enough to simply remove the upper weak layer and lay good soil on a dense base. If the dense soil is too deep, then it is possible to lay a dense “cushion” on a weak base, which requires special calculations and the movement of a larger amount of earth, which accordingly affects price works.

Deciding to order soil replacement, it should be borne in mind that the lowest price combined with an excellent result - this is cooperation with our team of professionals. Only with us you can quickly get advice, clarify the cost of work for the object and choose the most economical way of excavation! in winter, ready to offer inexpensive snow removal with loading to dump trucks in Moscow and the Moscow region

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