How and how to fill up an old well: we are mastering the technology of filling old well shafts. The blind area around the well - recommendations for the device The earth around the well is leaving how to stop

After the completion of the construction of the well, the time comes for its arrangement, aimed at ensuring ease of use and maintaining the purity of the water. An important element of such an arrangement is a soft blind area around the well, which will not allow melt and surface water to penetrate into the mine, and will provide you with a convenient approach to the structure.
Why do many experts advise making a soft blind area, what other ways are there to create it, what are their advantages and disadvantages? All this will be discussed below.

When to make a blind area and whether to do it at all

Let's start with the question - why do we need a blind area? Mainly so that polluted top water and melt water from the surface of the earth do not seep into the well with groundwater.
Her task is not to let them through to the shaft, to take them aside. Do not neglect the fact that a well with a blind area looks more aesthetically pleasing, and it is much more convenient to use it, standing on a clean and dry base.
However, the need for it may not arise under the following conditions:

• The well is located away from roads, industrial zones, in an ecologically clean place;
• It stands on a hill, which excludes the flow of surface water to it;
• Equipped with automatic water-lifting equipment that does not require your frequent presence at the well.

Now about when is the best time to make a blind area. The instruction says that not earlier than a year after the completion of construction, since during this time (and sometimes longer) self-compacting and sedimentation of the soil poured around the well shaft occurs, as a result of which voids and failures are formed.

Also during this period, a natural displacement of the upper ones in the horizontal plane is possible, which can also violate the integrity of the blind area. Therefore, its device can be started only after the completion of these processes and the elimination of their consequences.

Advice. In order to be able to safely use well water during this time, during the construction of the structure, it is necessary to make an earthen castle around it and a temporary pavement.

Types of blind area

The blind area at the well can be made of different materials: clay, concrete, reinforced concrete, as well as from a waterproofing film and sand.
The latter is called soft blind area. Let's look at the features of their device.

Solid types of blind area

They are made of clay or concrete with a thickness of 20-30 cm and a width of 1.2 to 2.5 meters around the entire perimeter of the structure:

• The clay blind area is a layer of compacted clay laid in a recess of the specified dimensions.
  Its main drawback is the formation of slippery and sticky dirt on the surface when water gets on it. This will require additional costs for the protective coating.

• The concrete blind area of ​​​​the well is carried out by pouring concrete into the formwork installed in the recess on a gravel pillow. To make it last longer, a reinforcing mesh is placed in the formwork before pouring the mortar.
  A prerequisite for the manufacture of such a blind area is the waterproofing of the outer walls of the well in the place where they will come into contact with concrete. This is necessary to prevent rigid adhesion to the frozen blind area slab.

Note. In any case, the blind area should have a slope from the well to drain water. Sometimes drainage grooves are also made in it.

The disadvantage of this type is the frequent formation of chips and cracks on the surface. They not only allow surface water to pass through, but also give the concrete surface an untidy look.
However, this is not the biggest problem - if desired, the blind area for the well can be repaired. But she herself, if the manufacturing technology is not followed, can damage the well shaft, violate its integrity.
The fact is that the forces of frost heaving act on the blind area, and if it is rigidly connected to the upper ring of the well, it can be separated from the lower one. As a result, a gap is formed between them, through which contaminated water and soil particles enter directly into the mine with clean water.

Soft blind area

This design consists of a waterproofing film, which is covered with a layer of sand. From above, a decorative coating or lawn is possible.
Its production does not require large financial and physical costs and consists of the following steps:

• Before making a blind area around the well, fertile soil is removed around it to a width of 1.2-1.5 meters;
• A waterproofing film is laid at the bottom of the recess, the edge of which is wound onto the upper ring;

• The film is fixed on the ring using double-sided tape or a metal strip, through which it is attached to the walls with dowels or screws;
• In the place where the film passes from a vertical to a horizontal position, a fold is necessarily made. It is designed to compensate for the displacement and subsidence of the soil at the base, which will prevent damage and destruction of the upper decorative layer;
• Sand is poured onto the film, on top of which paving slabs, paving stones, bricks, crushed stone, etc. are laid. You can simply return the previously removed sod to its place or sow lawn grass.

Benefits of soft blind area

In addition to the fact that the manufacture of such a design in an economy version will require a minimum of effort, it has a lot of other advantages:

• The most important thing is that there is no risk of a well shaft rupture along the seam between the rings;
• The soil around the well can sink and compact without prejudice to both the well itself and the covering of the blind area;
• Low price of materials used;
• If necessary, the soft blind area is easy to dismantle;
• A waterproofing film will do a much better job of removing water from the walls of the well than clay or concrete;
• The low labor intensity of the process - the blind area of ​​\u200b\u200bthe well with one's own hands in this case is carried out without problems and the involvement of assistants;
• Decent service life, reaching 80 years. Repair may be required only for the outer decorative layer;
• Finally, you can use any decorative finish from wood flooring to stone cladding.

Conclusion

The video in this article will help you better understand how to make a blind area for your well. It is important not to forget about all the rules and nuances of its device described in the article, so that in the future you do not have to remake or even repair the water source itself.

The device of the well is perfectly illustrated by the saying “Man proposes, but God disposes”: the success of an enterprise depends not so much on the skill of the builders, but on luck. One example of bad luck is when a well fell on quicksand.

When constructing a well, luck is required

What is a quicksand, how to deal with it and whether it is worth it - this will be discussed in the publication.

Quicksand: Great and Terrible

It is about him that there are stories that terrify: how, when digging a well, concrete rings are suddenly carried away in an unknown direction by a bursting stream of water and sand, along with the poor digger. Indeed, a collapse can occur in the well shaft and a person will suffer, or even die, crushed by soil and moving rings. And including the reason for the deformation of the mine shaft can be a quicksand.

True, it is unlikely that in the event of such an accident, the consequences will be like in a big-budget Hollywood disaster film with special effects - with concrete rings carried away into the distance by a turbulent stream. Maybe only if you are “lucky” not to get on a quicksand, but to pierce a stormy underground river with a well.

But quicksand is really dangerous and can do a lot of trouble. To feel it, I suggest watching the video.

Notorious for all Petersburgers, the metro line between the Lesnaya and Ploshchad Muzhestva stations passes through just such a dangerous place. Quicksand under the "Forest" brought trouble to the metro builders twice.

The first - back during construction, in the 70s (the Soviet film "Breakthrough" was filmed based on these events). Then, after the accident, to continue the work, the quicksand was frozen by pumping more than 8,000 tons of liquid nitrogen into the tunnel. But at the beginning of 1995, the quicksand returned, and in December, after numerous attempts to keep the erosion, the stations were closed until 2004.

What is a quicksand

Quicksand- it is a porous, loose soil saturated with moisture, consisting of unbound particles. Due to the large amount of water, such soil acquires the properties of a liquid - it begins to flow.

Quicksand is under pressure in a sealed cavity in the thickness of the soil. When this cavity is opened, for example, by a pit or a well shaft, the quicksand masses are set in motion under the action of the same pressure, and the masses of sand with water break into the formed working.

It is impossible to guess the location of the quicksand. Photo from otvali.ru

Most often, such formations are found on swampy soils or in floodplains of rivers. The thickness of the quicksand layer and its dimensions can be different. Outwardly, on the surface of the earth, the quicksand does not give itself away, so it is impossible to predict its location. As well as it is impossible to take measures to avoid meeting with him. Specialists distinguish true quicksand and false.

True quicksand

In its composition, in addition to pulverized sand, there are hydrophilic particles of clay or silt, which envelop larger grains of sand, acting as a lubricant. Even with a slight pressure, the mass of this sandy loam comes into a mobile state.

If it was a true quicksand that came across while digging a well, then you are really out of luck. True quicksands practically do not give up water - they have a low filtration coefficient. Therefore, it will not work to build a well in such a place: instead of water, it will contain a viscous clay-sand solution.

False quicksand

Fortunately, true quicksand is not so common. Usually, when digging a well, they encounter pseudo quicksand. There are no colloidal particles in the composition of false quicksand - it is a soil consisting of fine sand and a large amount of water.

Dense sand saturated with water liquefies under pressure

To imagine how a quicksand behaves, remember the sand at the water's edge. It looks hard and almost dry, but as soon as you step on it, it becomes fluid and water appears.

In order for a false quicksand, unlike a true one, to move at a depth, it is necessary to apply significant hydraulic pressure. If a false quicksand is caught in the way of the mine, then it will not interfere with the construction of the well. Moreover, a well on a quicksand is distinguished by a special water content in comparison with the usual one. However, it will complicate the life of both diggers and the owner of the well during its operation.

How to deal with quicksand

It is better to entrust digging a well to specialists who have experience with quicksand and can quickly make the right decision. If you decide to dig on your own, you must follow the safety precautions:

• the walls of the well must be strengthened, that is, it is impossible to arrange a well on complex loose soils without rings;
• a partner should be at the top, and the digger should have a safety rope so that, if necessary, it would be possible to immediately lift a person: the quicksand can start to move suddenly;

• if there is reason to believe that the quicksand layer is of small thickness, and a decision is made to pass it, then you need to work as quickly as possible, and if it is impossible to pass, stop and arrange a water intake in the quicksand.

Work in the well. Photo from the site stroytalk.ru

In the old days, for the passage of a quicksand, in addition to the speed of work, the strengthening of the walls and the installation of a tunneling shield that fences off the quicksand and slows down the flow of water with sand into the well, they “bind” the water-saturated soil by adding a substance that absorbs water. If moisture is taken away from a false quicksand, the sand becomes compacted and loses its quicksand qualities.

For this, for example, several bags of flour were poured into the well and mixed with a water-sand slurry. After a while, the flour absorbed water, and work could continue.

Another option is to dig a well in winter. At this time, firstly, the GWL is the lowest, and secondly, the soil freezes through.

Quicksand well

Do not be upset that a quicksand was caught while digging a mine: more than 40% of wells in the Moscow region are arranged in such conditions. As mentioned above, such wells usually have a high flow rate (that is, the rate of water inflow into them is high), and sand is an excellent filter. You just need to accept the inevitable sand flooding as one of the features of your well and deal with it correctly.

Exploitation

You should not try to pump sandy slurry out of the well: the more you pump out, the more it comes. And this is fraught not only with a useless waste of energy: the sand entering the well is carried out by water from the outer walls of the mine, and cavities form there.

And this is where the development of events according to the scenario of disaster films turns out: it is possible to move the soil and shift the rings with all the sad consequences. In addition, in the cavities formed in the soil, the surface layer of the soil can settle. And if there is a building nearby, then the weakening and even destruction of its foundation and the building itself is likely.

The metro station Ploshchad Muzhestva in the film about the Leningrad metro accident. Photo from masterok.livejournal.com

Some subsidence of the soil is inevitable - this is normal. It is worth being patient and waiting until the soil around the new well is compacted and the “well-aquifer” bundle comes into balance. Only after that it is possible to arrange a blind area around the head of the well. The process of compacting and subsiding the soil can take several years.

After the situation stabilizes and the soil stops actively flowing into the mine, you can try to remove the applied sand until the quicksand begins to manifest itself again. And then you have to wait again until the system calms down. You may need to repeat the procedure again.
It is impossible to use a submersible vibration pump in a well on a quicksand, as it will lift the sand at the bottom with its work. It is necessary to install a pump with surface water intake.

Surface pump connection diagram

It is also impossible to pump out water in one burst (at a time), at least a third of the usual volume should always remain in the well, and preferably at least half. The intake of a large amount of water can "wake up" the quicksand. It is better to organize a storage tank on the surface, the volume of which obviously exceeds the daily water consumption, and install a low-power pump that fills it. And the entire water supply system of the house should be diluted from the storage tank.

And most importantly, you should not use shields and arrange a bottom filter in an attempt to keep quicksand. You can find out about the reasons for this in one of the following publications.

The presence of bottom sediments with a thickness of more than half of the ring and blockages, sudden turbidity, a washout or failure of the soil around the well - all this usually indicates its improper functioning and the need for repair. Most likely, there was a violation of the integrity of the water intake column - the displacement of the rings, the rupture of the column, the depressurization of the seams and technological holes and the entry of heavily watered pulp through them into the source. A possible reason for the appearance of blockages and turbidity is the activation and rise of the quicksand due to suffusion or water hammer from the bottom.

Photo 1. Vertical and horizontal displacements of rings in quicksand.

Photo 2. Reinforcement of seams and installation of a bottom filter.

The processes of frost heaving, the blind area rigidly tied to the upper ring, floods and seasonal fluctuations in the level of groundwater, a sharp decrease in the level by a powerful drainage pump and complete pumping out (draining) of the source contribute to the emergence of an emergency. Perhaps the recent cleaning or repair made by non-specialists, the vibration pump of the "Kid" type in quicksand and just time itself - since nothing lasts forever.

Photo 3. The failure of the earth, formed on the surface after the rupture of the seams.

Photo 4. Consequences of deepening the well with repair rings without reinforcing the seams.

If there was a failure or the earth around the well collapsed - this usually happens in the spring due to the formation of voids behind the rings, into which the soil sags over time. Voids are formed as a result of the removal of soil from the annulus into the well, creating blockages at the bottom. Most often, the failure is associated with frost heaving or quicksand activation, the consequences of which are: horizontal and vertical displacements and shifts of the column, seam ruptures.

Photo 5. To align the displaced ring, it is necessary to excavate until it breaks.

Photo 6. The excavation is carried out up to the displaced seam (usually up to the 2nd seam from the top).

Due to frost heaving in winter, the upper rings are detached from the zone of seasonal freezing, and ruptures of the seams are formed. In the spring, melted surface water begins to actively flow into these gaps, eroding the soil in the annulus. The eroded mass ends up in the well, forming blockages at the bottom, and yellow muddy water appears. Voids form around and in the spring, when thawing, the earth falls into them. For repairs in such cases, the following is required: leveling the well column (if necessary), reinforcing broken seams, removing soil blockages from the bottom, sealing the seams, restoring the clay castle and blind area.

What to do if there is little or no water in the well, it has disappeared, partially or completely gone, there is a bad inflow or it has dried up completely? The well is preliminarily diagnosed and cleaned, based on the results of which a conclusion is made on the need for further actions to restore your source of water supply.

Before carrying out repair work, the state of the well is diagnosed and, usually, the subsequent reinforcement of the well column is the installation of metal brackets on anchor bolts at all seams to eliminate the possibility of its rupture and maintain the integrity of the column. Reinforcement is mandatory on the quicksand.

Non-regular gaps in joints with a width of more than 5 mm are sealed with special fast-hardening mixtures with the addition, if necessary, of various fillers, such as foam, brick, rubble stone and others. Sealing of irregular seams and removal of soil blockages from the bottom with a thickness of more than 40 cm are paid separately.

Repair and restoration of the well with a plastic pipe

Plastic stocking is a technology that allows you to restore (reanimate) the integrity of the water intake column, the repair of which is impossible by other means, excludes the influx of muddy water through ruptured seams and other depressurized holes. This technology will help if:

• there was a rupture of the water intake column after cleaning or repair by unskilled "specialists";
• annual horizontal and vertical displacements of the upper rings occur as a result of frost heaving of the soil;
• the seams are constantly flowing and it is impossible to seal them in other ways.

Photo 1. Installing a plastic stocking is a solution to many problems with a water source.

Photo 2. Plastic pipe for well casing.

The technology consists in installing a plastic pipe (stocking) into an existing well from standard reinforced concrete rings of various diameters and then filling the annulus with various materials that act as a filter. Water, passing through such an artificial filter, is additionally purified and enters from below, exclusively through the face (bottom). The complex of works is divided into 3 stages.

Photo 3. The annular space after the installation of the stocking is packed with a special backfill.

Photo 4. Upon completion of all work, washing and finishing pumping is carried out.

Stages of work:

1. Preparatory work before installing the stocking (diagnosing the state of the source, assessing the possibility of installing a plastic pipe, agreeing on the types and volumes of materials, calculating estimates, preliminary cleaning). This type of work is carried out by specialists of the company "My Water". 2. Delivery to the facility of the agreed quantity and type of backfilling materials, as well as a plastic pipe of the required size and diameter. This type of work is performed by the Customer. 3. Assembly of the stocking, backfilling of the annulus, installation of a bottom filter, final washing and pumping. This type of work is carried out by specialists of the company "My Water".

The required type and volume of backfill materials (coarse-grained sand, ASG, fine-grained crushed stone or sand concrete), as well as the size, type and other necessary characteristics of the plastic pipe are determined on site during diagnostics by My Voda specialists.

Photo 5. Corrugated two-layer plastic pipe.

Photo 6. Brown 6-meter plastic pipe with a socket for casing.

A prerequisite for the installation of a plastic pipe is the absence of water-lifting equipment or, if available, it should not interfere with the installation of the stocking.

Do not forget that the supply of wells arranged in clay soils with low water loss occurs exclusively through the seams - therefore, backfilling of the annulus in such cases is possible only with highly permeable materials that can prevent a significant reduction in the filling rate and volume of water in the source.

Cost of work: installation (installation) of a plastic pipe in a well - the price is from 15,000 rubles. (depending on diameter and size); additionally - preliminary cleaning, installation of a bottom filter, final washing of the column and pumping of the well upon completion of all installation work. Prices for these works.

Removing blockages in a well

Excavation of littered (swollen) rings is a separate type of work, it is not included in the cost of cleaning and repair. In the event that the source, for some reason, turns out to be littered with soil with a thickness of 40 cm or more, the specialists of the Moya Voda company will excavate the swollen rings. Blockages are formed for various reasons:

• significant rupture of the seams, often with displacement;
• ground failures;
• a well column hung above the bottomhole (more excavated than cased);
• water-bearing rocks are composed of quicksand soils.

Photo 7. Blockages at the bottom caused by the rupture of the upper seams (about 80 cm blocked).

Photo 8. Strongly watered pulp at bottomhole.

If there is quicksand in the well, then due to suffusion, the sand rises through the face (from below) and tightens, on average, half of the ring. The formation of blockages at the bottom also often occurs due to torn seams when 1-2 lower rings fall asleep. In our practice, there was a case when blockages reached 6 meters.

Photo 9. Removal of blockages from the bottom. Digging out swollen rings.

Photo 10. Heavily watered soil extracted from a well.

A large amount of land at the bottom is an indicator that the well needs repair. The cause of the soil ingress is established on site and a method for its elimination is determined, after which the necessary work is carried out. The cost of digging - from 2000 rubles / ring.

Quicksand well repair.

Quicksand is a water-saturated soil (fine-grained and silty sands, non-cohesive and slightly cohesive sandy loams and colloidal clays), which, under mechanical action, is prone to liquefaction and slumping. The finer the particle size distribution, the lower its bearing capacity.

The volume of water in the quicksands is 1-1.5 rings, the water column is 80-120 cm. Under hydrodynamic pressure, the quicksands liquefy and a water hammer occurs - a sharp flow of a large volume of soil into the working and siltation of the well. When sinking into them, it is necessary to observe increased security measures, since cases with a fatal outcome are not uncommon.

When working in quicksand, be sure to:
1. Strict observance of safety regulations
2. Reinforcement of all seams with metal staples on anchor bolts

To exclude the possibility of water hammer and silting in such cases, it is not recommended:
1. A sharp drop in the water level during pumping
2. Complete pumping out of water
3. The use of vibration pumps such as "Kid", "Brook", etc.

Clay castle and blind area

The so-called clay castle prevents seasonal melt and rainwater from entering from the surface, thereby reliably protecting and preventing deterioration of the water quality in the source. The initial high-quality performance of a clay castle and the constant proper maintenance of its technical condition are the key to the long service life of your well and high-quality water in it.

For more reliable protection, a blind area is arranged over the clay castle. If the filling around the well is made with ordinary soil, then rain and seasonal melt waters begin to actively erode and seep into it over time. This leads to a deterioration in water quality: a change in the chemical composition, turbidity increases sharply, and the likelihood of bacteriological contamination increases. You can often see such a picture yourself during the period of active snowmelt in the spring or after heavy rains.

So, according to research conducted by various organizations, the quality of groundwater in the spring is deteriorating greatly. The concentrations of various trace elements and bacteria dangerous to humans increase significantly and exceed the MPC by several times, and sometimes by an order of magnitude. A set of measures, such as arranging a blind area, a reliable clay castle and waterproofing the upper rings, largely prevent such consequences and work as a reliable protection against pollution.

Constantly monitor the technical condition of the building. The resulting dips and gullies should be immediately filled up, restoring integrity. This will prevent contamination from entering the source and significantly reduce the likelihood of repairs or cleaning.