Sand borehole construction, advantages and disadvantages of sources of this type. Mine drilling methods. Step-by-step instructions for creating a well using the auger method. A well on sand is a vertical shaft from the surface to a subterranean horizon saturated with moisture, where free-flow groundwater is located. It is a very popular site water supply option that can be created in a short period of time. We will talk about drilling a well in sand with our own hands in this article.
Well construction on sand
The well on the sand was named according to the composition of the underground layer from which water is extracted. It is a loose mass oversaturated with moisture, surrounded on all sides by clay layers. The formations are small in size, located at a distance from each other, so there is no single aquifer of this type. For this reason, drilling is often ineffective.
The sandy layers are located below the upper water, and the liquid in it is cleaner. The well on the sand is the golden mean between the Abyssinian and artesian wells. The source debit is 0.6-1.5 m3 water per hour. This amount of liquid is enough for watering a small area and living for 2-3 people, so it is very often built in summer cottages. For very low flow rates, it is recommended to install a storage tank next to it and use two pumps. The first fills the tank from a source, the second supplies liquid to the water supply system of the site. However, for country houses with a large family, it is impractical to build a well on sand - low productivity does not provide living comfort.
The device of a water well on sand is traditional: to strengthen the walls, casing strings with a diameter of 100-150 mm are installed in the mine and connected to each other using a thread, clamp or welding. The choice of the pipe diameter is influenced by the size of the pump - a gap of at least 7 mm must remain between the product body and the barrel walls.
As casing strings for sand wells, pipes made of various materials are used, which are selected depending on the drilling method. Stainless steel metal products are versatile and can be used with any tool, but they are very expensive. Plastic ones are cheaper, but they are not recommended for auger drilling - the tool can damage the walls. You should not buy asbestos and galvanized pipes due to the presence of elements harmful to humans.
At the bottom of the column, a coarse filter is attached to retain large particles. The top of the casing is called the head. It prevents debris from entering the barrel.
The casing can be installed in the shaft in two ways - after the end of drilling and in parallel with it. In the first case, the soil must be clay, otherwise the walls will collapse.
Advantages and disadvantages of sand wells
A sand well has a number of advantages over alternative sources:
- It has obvious financial attractiveness, since it can be dug out with a small drill rig. Moreover, the depth of the mine is not very great.
- The construction of a well does not require permission from local authorities, as for an artesian source.
- Water can be pumped out of it with an inexpensive vibration pump.
- The technology of drilling wells into sand is not complicated. The work is done in the shortest possible time.
During work, problems may arise that the owner should be aware of:
- It is impossible to accurately determine the location of the water-containing "lenses".They may not be under your site, even if your neighbors have such a well.
- The sandy horizon is sometimes at a great depth, and you can manually drill a mine only 25-30 m. To extract fluid from a greater depth, you will have to hire a team with a car installation.
- Water in sandy wells can be polluted by sewage; it is not recommended to drink it without first boiling it.
- The quality of the liquid varies with weather and season.
- In a water well, sand often clogs the filter and has to be cleaned once or twice a year. The cleaning procedure is lengthy, complex and expensive.
- The filter in sand wells is not replaceable. If aggressive substances are present in the soil or liquid, it will quickly fail, and the trunk will have to be dug again.
- Despite the presence of a filter, the smallest soil penetrates into the mine, which will shorten the life of the pump and various water supply devices. Because of it, expensive high-performance pumps or pumps cannot be used.
- The service life of a well for sand is short - 5-15 years.
- Even with regular cleaning, the source quickly silts up. Therefore, it is not recommended to create such a well for periodic or seasonal use - it is necessary to constantly take water from it.
Features of drilling a well on sand
The depth of the well for water does not exceed 50 m, which allows you to create it yourself. The underground layers are located one above the other, but not all have enough moisture to be pumped out by a pump. It is necessary to stop work if wet sand begins to flow to the surface. The larger the particles of the free-flowing mass, the more liquid they contain and the faster they get rid of it.
The sandy aquifer is not everywhere, so it doesn't hurt to ask your neighbors what type of wells they have before starting drilling. You can also get information about the presence of useful layers from the company that digs wells in your area.
You can manually drill a well into the sand in several ways:
- Rotational… For work, a spiral cutting tool (auger) is used, which enters the ground when rotated manually or with the help of a motor.
- Impact-rotary… The device is thrown into the mine from a great height, and after stopping, they begin to scroll. The crushed soil is brought to the surface.
- Rope-percussion… In this case, a thief is used - a tool in the form of a cylinder with a valve, which is thrown into the barrel. It goes deeper into the bottom, the soil enters the device, and then is removed.
In all drilling options, it is necessary to periodically raise the device to the surface and free it from the soil. If not cleaned, it will get stuck in the shaft. Professional drillers, when turning the tool, supply water under high pressure into the mine, which removes the crushed soil from the wellbore. But such equipment is expensive and requires skill to operate.
Various tools are used to create a mine. Information on the applicability of each device is given in the table:
|Tool||Application||Drilling method||Borehole depth|
|Screw||For clay soil, ordinary soil, loam||Rotational||Up to 30 m|
|Boer spoon||For sandy and loose soils||Rotational or shock-rotational||Up to 30 m|
|Drill glass||For sticky and sticky soils||Shock rope||No restrictions|
|Bailer||For passing quicksand and cleaning the well after drilling||Shock rope||No restrictions|
With a very deep occurrence of the aquifer, rotary drilling is used with a mobile vehicle installation. For this purpose, specialized organizations use the technology of rotary percussion drilling with the supply of fluid through the internal cavity of the tool into the borehole. The stream rises to the surface and brings the earth out.
The water in the well on the sand is necessarily subjected to chemical and biological analysis.Very often the liquid in such wells is moderately hard with a small amount of dissolved iron. If it is used for cooking, check it several times a year after floods and heavy rainfall.
How to make a well for sand?
The principle of drilling holes into sand is the same for all methods - the soil is crushed with a special tool and brought to the surface. To lift a heavy tool from the ground, you will need a tripod and lifting mechanisms - a winch or a gate. Consider the popular methods of drilling a well in sand, as well as methods of making fixtures and individual parts for it with your own hands.
Making a tripod with your own hands
It is easy to make a tripod yourself from logs or pipes 3-4 m long. The height of the device should be such that, after hanging the tool or knee, the distance between it and the ground remains 1.5-2 m.
The device is assembled in the following sequence:
- Knock down a tripod from logs with a diameter of 15-20 cm, securing the bars in the upper part with nails or in another way.
- Connect the bars to each other at the bottom with slats so that they do not disperse.
- Attach a winch hook to the top of the attachment, which will lift the tool with the ground.
- The load can be lifted with a collar, which is fixed at the bottom of the tripod. In this case, instead of a hook to the corner of the tripod, fasten the block and pull a thin cable or strong rope through it.
Well filter manufacturing
A coarse water filter is attached to the bottom of the casing before it is installed in the shaft.
You can make it yourself from the knee, for which you can perform the following operations:
- In the pipe cut, make holes with a diameter of 3-5 mm at a length of 100 cm. Do not drill too much, the barrel will lose strength. Instead of holes, you can cut grooves with a grinder. Slots should be 2.5-3 cm long and 1-1.5 cm wide.
- Sharpen or jagged one end of the knee. The shoe will facilitate the movement of the casing in the well.
- On the other side of the workpiece, cut the threads to connect to the adjacent elbow. On the remaining parts, make the threads on both sides.
- Wrap the perforated part of the pipe from the outside with a fine mesh and secure it. On the knee, you can screw the stainless wire not too tightly, and then solder it to the body.
- It is allowed to install the filter after installing the casing. In this case, you will need a factory-made product, the diameter of which is several millimeters less than the inner diameter of the casing.
Mine Drilling Instructions
Let's consider the sequence of work when drilling a mine using a screw with a parallel installation of the casing string.
Work on the construction of a well for sand is carried out in the following sequence:
- In the chosen place, dig a pit, in which the caisson will subsequently be placed - a box for storing the pump, filters and other equipment for the water supply system of the site. The caisson also prevents the well from freezing. The dimensions of the pit depend on the dimensions of the caisson. Make the width 1 m wider than the structure. The depth should be below the level of soil freezing in the area, usually within 2 m.
- Place a tripod over the pit. Attach a lifting device (winch, gate, etc.) to it.
- Hang the drill on the chain and lower the point to the ground. He will indicate the center of the well. Move the tripod to a new location if necessary.
- Dig the tripod supports 0.7-0.8 m into the ground, thus securing against movement.
- In the marked brown spot, dig a recess for 2-3 bayonets.
- Place the auger in the pit with a winch.
- Secure the collar and rotate the drill until it is halfway down.
- Pull it out of the hole and clear it off the ground.
- At the bottom of the pit and above it, install two wooden planks with holes. Their diameters are equal to the diameter of the casing.
- Align the centers of the holes with the center of the shaft.
- Install the lower part of the column with the filter into the shaft through the holes in the decks.
- Check its verticality using a level or plumb line. If necessary, ensure verticality by moving the decks horizontally or vertically.
- Fix the shields from moving in any plane. The design should resemble a casing that will not allow the casing to deviate to the side.
- Install the drill into the borehole until it stops.
- Disconnect the chain from the auger and attach a 1-1.5 m extension to it.
- Hang it on a chain.
- Move the clamp to the extension and lower the auger.
- Rotate the tool until it is 20-30 cm deeper and lift up to clean.
- Upset the casing.
- Lower the auger and repeat the operation.
- After the drill is completely in the ground, lift it to the surface and disassemble.
- Extend the filter with your elbow.
- Place a drill in it, attach an extension, and continue drilling and settling the casing until it reaches the aquifer. During operation, constantly check the verticality of the column.
- Stop drilling when the tool has penetrated the sandy layer and entered the clay layer below it.
- Remove the auger from the barrel.
- Settle the casing at a height of 10-15 cm from the lower clay layer.
- Clean out any dirt from the well with a thief.
- Lower the pump into it, which is designed to pump out the semi-liquid mass, and remove all the dirt. Repeat the operation several times until clear water appears in the mine.
- Swing and clean out the well.
- Pour gravel and crushed stone into the trunk in a layer of 15-20 cm to form a bottom filter.
- Lower the casing on top of it.
- Install the caisson.
- Install a pump in the source and place all equipment for operating the well in the caisson.
How to make a well for sand - watch the video:
Installing a well on sand has its pros and cons, so the site owner must decide for himself which source he wants to build. However, such a well is considered ideal if there is little finance, and the result is needed after a short period of time.