Construction of a well without a caisson: options and technologies

If a well is drilled on the site, it is worthwhile to establish an autonomous water supply system. But the organization of a private water intake in a standard way with the installation of a caisson is a very expensive undertaking. It is not necessary to spend substantial sums on this dimensional structure.

We will show you how to build a well without a caisson. For you, we brought step-by-step technologies, described in detail the methods and nuances of implementation. For a visual perception of information and a clear understanding of the working processes, we have added material with photo and video instructions.

Pit construction: pros and cons

If you can not spend impressive money on caisson device, the problem is solved in two ways: a pit is being constructed and settled down or a downhole adapter is installed.

The simplest solution in terms of installation is a pit.

It is a simplified analogue of the caisson, which simultaneously performs several functions:

• protects installed equipment from cold;
• protects the wellhead from precipitation and domestic sewage;
• acts as a structure inside which it is convenient to place a set of mechanisms ensuring the smooth operation of the pump.

Due to the lack of tightness of the structure, the sumps are not suitable in areas with close to the surface occurrence of groundwater. With the mark of their mirror at a depth of more than 5 m, the construction of the pit is quite a profitable and justified decision.

The only drawback is the lack of tightness. Joints between concrete rings and masonry can skip overhead and precipitation and household drains. For this reason, it is not recommended to install a hydraulic tank and an automation system in the pit.

Do-it-yourself construction pit

Earthwork is desirable to carry out in the offseason. During this period, the cooled wet soil has a more dense structure and therefore is not so showered.

Digging the pit

For the construction of the pit, they excavate a pit with a depth of 1.5-2 meters. Its dimensions should be 30-40 cm larger than the internal section of the structure being constructed. The bottom of the pit is leveled and carefully tamped. To protect the walls of the pit from the ingress of water, it is necessary to cover them with film for a while.

The most popular and simple ones are rectangular and round pits.

Whether it is necessary to concrete the bottom of the pit is a controversial question. On the one hand, the monolithic “floor” is convenient for carrying out repairs and well maintenance.

It will prevent the penetration of flood waters into the annulus in the event of flooding the structure in the offseason. However, ground movement, which occurs due to periodic freezing and thawing, can significantly damage and distort it.

The best way of arranging the bottom of the pit is to build a “pillow” of rubble and sand 10-15 cm thick. Clay can be used as a waterproof layer. The pits resulting from the shrinking of the soil will only need to be leveled periodically.

Wall construction

The walls of the pit can be constructed using concrete rings for wells or broken bricks remaining after the dismantling of any construction. For the construction of walls of the desired thickness of the brick is laid in a single layer.

If desired, the walls of the structure can be made concrete. To do this, from the old unedged boards they form a formwork at a distance of 7-10 cm from the walls of the pit to install reinforcing mesh. And then the formwork cavity is poured with concrete.

After 5-7 days, when the solution acquires the necessary strength, the pit is covered with wooden beams or planks.

To reduce the likelihood of erosion of the walls of the pit with floodwater, they are covered outside with a layer of gravel. On the inner side of the building it is better to lay out a layer of insulation, for example, sheets extruded polystyrene foam.

The pit cap can be covered for selection:

• concrete cover;
• metal hatch;
• boardwalk, reinforced with wooden bars.

The lid of the pit is removable so that you can have a routine inspection or repair work at any time. For example: dismantle the pipe or lift the pump.

The pit is essentially an improvised caisson. Simple ways of arranging it are described in the article - How to make a caisson for a well with your hands: options for the device and how to implement them

Construction of the wellhead with a tip

If the wellhead is not buried in the ground, it will be equipped with wellhead installations. It will protect the water from dust and dirt, as well as from the entry of insects and rodents into the trunk of the mine.

The disadvantages of an open arrangement scheme is the inability to place additional equipment near the mouth and the lack of protection against the encroachments of vandals.

Device and principle of operation of the adapter

The second inexpensive way of well development involves the use of a special device - an adapter. In this case, the withdrawal of water pipes through the casing.

This method of arrangement is excellent for irregular use of the well, which presupposes "freezing" the structure for several months, and for continuous year-round water intake.

Installing the adapter is done on all types of casingmade of polymer or steel alloy. The pipes must have sufficient strength, as they are designed to withstand the weight of the submersible pump and the communications connected to it.

The adapter is a device consisting of two body parts, fastened together by a quick-disconnect threadless connection. The main task that is solved by installing this device is to protect the outer branch of the water supply system from freezing.

Thanks to its use, the pipeline from the well can be laid below the horizon of seasonal soil freezing.

The main elements of the adapter are:

• Fixed element. It is a threaded nipple. It is fixed on the casing below the level of freezing through a specially made hole. It forms a sealed unit for the exit of the pipeline that supplies water to the house.
• Counter removable element. It looks like a tee with a single blank wall. On one side it is mounted on a water intake pipe leading to a submersible pump. The second is connected to the stationary element of the adapter. It is equipped with a connecting technical thread, which is necessary for hermetic joining of both parts of the adapter.

In the process of pumping out of the well, the water first rises upwards along the column, then moves to the adapter, through which it is redirected and enters the pipeline leading to the house. With the partial separation of the elements, the water begins to simply merge into the well.

Borehole adapters are made of bronze, brass, stainless steel. In a wide assortment on the market are products made from combined metal alloys.

Advantages and disadvantages of using the device

A well without a caisson device, equipped with an adapter, has a number of undeniable advantages.

Among the main advantages of this type of arrangement it is worth highlighting:

• Cost savings. The cost of the device is many times lower than the price of decompression equipment. And the cost of its installation and connection is minimal.
• Easy installation and maintenance. The installation of the device does not imply difficult stages of work with the use of the same welding equipment. It can even be performed by a master with only basic repair skills.
• Versatility of use. The device is used for cutting water in all types of casing. Due to the fact that the links of the device are tightly adjacent to each other, the maximum tightness of the structure is achieved.

The compact dimensions of the adapter allow it to be installed on the walls of the well, so that it becomes almost imperceptible to outsiders. And this is especially true, provided that theft is not a rare occurrence.

True source, equipped with an adapter, has several disadvantages.

These include:

• The complexity of the repair. To perform repair operations or routine inspection, you will first have to dig out the adapter's connection point, which is not always possible.
• Power limitations. Although manufacturers claim the device’s ability to withstand large pressure drops, but with however, it is not necessary to select pumping units with large performance.

In comparison with the arrangement of the pit, the installation of the adapter loses in that hydroaccumulator, cranes and automation systems will have to be taken out in a separate room.

In addition, in case of improper connection of elements during the operation of a hydraulic structure, it is quite problematic to control the return flow into the groundwater production trunk.

Depressurization of elements may occur even if the connecting elements of the structure are made of unequal metals that have different aging wear and react differently to the effects of temperature and moisture.

Adapter Installation Technology

When choosing an adapter for the well arrangement, match the size of the device with the diameter of the casing and the size of the submersible pump, if it is planned for operation.

To perform the work will require the following materials:

• downhole adapter;
• crown cutter;
• puller;
• connecting fittings;
• metal stakes.

When calculating the dimensions of the device, be aware that it should protrude approximately 1-3 cm from the inside of the casing.

To treat the structural elements before digging in the insertion points, use a neutral water-repellent grease.

From the tools should be prepared:

• bayonet spade;
• bucket for dredging;
• adjustable wrench;
• mounting pipe;
• Fum tape.

The assembly key can be made by hand from a metal or plastic cut of a pipe of suitable diameter with a thread. As a result, it will take the form of a T-shaped structure, the length equal to the installation depth of the device plus half a meter-meter for ease of installation.

The thread is needed in order to be able to screw the mating part of the adapter onto it. The opposite end is equipped with a tee, which simplifies the process of unscrewing the device after fixing the mounted part of the device.

Excavation work

To lay the pipeline, you must dig a trench from the well to the point where the system enters the house. The depth of the trench is 30-40 cm below the level of seasonal freezing. They are needed for the formation of compacted sand cushion of about 20 cm and to the exclusion of the likelihood of accidental freezing of the pipeline.

For mid-latitudes, the level of seasonal freezing of soils is estimated at 1.2-1.8 m, depending on the type of soil.

When digging a trench, it should be noted that the pipeline should be laid with a slope from the house to the hydraulic structure in case of draining water from the system before conservation. The slope should be 3 cm per meter.

That is, we look for the depth of the adapter's connection point by adding the freezing level, 30-40 cm to the pillow unit and multiplied by 3 lengths of the external branch of the aqueduct.

If the distance from the house to the well is 10 m, the calculation will look something like this: 1.5 m + 0.4 m + 0.3 m.

Next to the well, the trench needs to be expanded and digged into something like a pit, the dimensions of which are determined on the basis of the convenience of placing the adapter installer in it. To perform work on the insertion of the device, a pit half a meter wide is sufficient.

Well Equipment Pitless Adapter

Installation of equipment is carried out in two stages. First install the main part of the device. To do this, at the depth of laying water with a crown cutter on the casing pipe bore hole. The diameter of the hole can be equal to 1ʺ, 1 _1/4or 2. The main thing is to match the size of the adapter.

The stationary part of the device is introduced into the hole drilled in the casing and fixed with a cap nut. The nut with the help of the adjustable wrench tighten all the way.

Rubber gasket seals ensures the tightness of the structure at the joints, minimizing the likelihood of ground water entering the well.

Before mounting the device mate pipe, electrical cable and cable attached to the pump. The cable and electrical cable should be oriented in such a way that they take their place from the opposite side of the adapter.

The water pipe is fixed by means of a threaded connection through the coupling. In order to increase the tightness of the connection, compact the FUM with a tape.

Since in the process of operation, the vibration of the pump, complete with the severity of the pipe filled with water, will create significant loads, to connect the adapter to the riser pipe should be used brass coupling.

The difficulty of mounting the counterpart of the device lies in the immersion and exact contact with the thread of the stationary element. You can ease your task by using a T-shaped mounting pipe. To speed up the process, some masters additionally illuminate the hole with a flashlight lowered on a rope.

Parts of the adapter are connected by means of the “dovetail” assembly. The counterpart of the device is fixed with a mounting pipe. After installation is complete, the mounting tube is removed to the surface.

After completing the system assembly, to a predetermined depth lower the pumpand the end of the pipe is cut. It is more convenient to perform this work with a partner: the first one immerses the pump, the second one holds the equipment and straightens the hose.

At the final stage it remains only to power the equipment and check its operability.

During the subsequent operation of the facility, it is necessary to check the condition of the adapter seals once a season. Keep in mind that contact with the ground outside laying becomes useless for 2-3 seasons.

Connecting elements may eventually stick to each other. To prevent this phenomenon, it is necessary to periodically disassemble and lubricate them.

Additional information about the features of installation and use of the downhole adapter is presented in this article.

Conclusions and useful video on the topic

What is better: downhole adapter or caisson?

Video tips on the construction of the pit:

Option well arrangement by installing the adapter:

Each of the above methods has its advantages and disadvantages. Therefore, when choosing the best option, it is necessary to focus on the location of the hydraulic device and the type of equipment used in the arrangement of the system.

Have experience in arranging a well without a caisson? Or have questions on the topic? Please share your opinion and leave comments in the form below.