Using a pile with a casing instead of an ordinary well and piles , you can get not only the most high-quality and more durable foundation, but also a structure that can be quickly removed to be repaired if necessary. The technology of bored piles with casing is most often used in cases where the soil is very difficult to use.
Pile Description
For arranging a buried foundation, the use of a pile structure with casing is the best option. The arrangement process is quite simple. It is necessary to use a drill to drill a well of the desired diameter and depth. The difference from conventional piles is that the lower base is wider than conventional equipment. The presence of such an addition allows you to add substances such as concrete, soil, sand or other materials as necessary. Obtaining such a spacer in the lower part is carried out due to special equipment of the expanding type, which bursts the rock below.
General classification of piles
In order to get a cylindrical hole in the ground, it is necessary to use special devices. Depending on the use of a particular design, several types of piles are distinguished . In addition to bored, it can be sandy, soil-concrete, pneumatic, vibro rammed. The main selection criterion for using this or that technology and piles is the type of soil that is present on the site. However, it is worth adding that the current development of technology has led to the fact that the same method can be used on almost any type of soil, regardless of its characteristics. To verify the effectiveness of the method that you intend to use, you must have specialists.
Casing purpose
The use of casing pipes allows you to get wells with different functional purpose. You can use them in areas such as construction, oil production, arrangement of wells, etc. To make such devices, use various materials, but the most popular of them are asbestos cement, stainless steel, plastic. From a material such as cast iron, wood or some polymers, it is possible to manufacture piles with a limited margin of safety. The main purpose of all these structures is as follows: protection of the completed well from the shedding of the earth. Using bored piles without casing is not very effective, since such products cannot be installed on any soil. If the casing is used, then the restrictions are removed, and you can apply the pile on any type of soil. It is worth noting that casing pipes are products that are removed from the well either immediately or after some time, but they do not remain inside together with piles. Such devices are usually called inventory. In order to drill a well and hammer a pile, either drilling equipment or percussion is required.
Types of Casing
Naturally, the pipes differ in such parameters as shape, ovality, difference, indirectness, diameter. Casing pipes for bored piles are available with the following standard parameters:
- pipes with parameters from 33.5 to 89 mm in diameter - the error is up to 0.3 mm;
- products with a diameter of 108-144 mm are produced with an error limit of up to 0.5 mm;
- All pipes with a large diameter can have an error of up to 0.7 mm.
Most often, casing pipes for bored piles are made of asbestos cement, while they are usually thick-walled. However, they are considered the most fragile of all other types of products. The great popularity of this equipment is due to the fact that the cost of parts is quite low, and products in general are the most affordable. When working with casing pipes for bored piles or any other, it is necessary to be guided by clear rules that describe the phased completion of all work.
Pros of using bored technology
Using casing allows you to get a fairly reliable reinforcement of soil walls. The pipe itself consists of several sections that are rigidly interconnected. The advantage of using bored pile technology with casing is not only that it can be used on any type of soil, but also that they are excellent for construction work in the city, when the working space can be significantly limited.
As for the process of carrying out all installation work, as well as their cost, these factors are affected by the following factors:
- state of the drilling mechanism;
- the size of the well to be drilled;
- type of soil on the site where construction work is carried out.
It is worth noting that the construction of bored piles with casing, as well as the technology for their use, is not too complicated.
Installation Procedure
When operating casing pipes for bored piles, as well as the piles themselves, it is necessary to adhere to a certain order of installation work.
- After preparing the terrain on the desired site, the installation of bored equipment is carried out. After that, the well is drilled in sizes that are usually indicated in the design documentation.
- If the casing is made of a material such as metal or plastic, then a twisting barrel is used.
- In order to fasten individual sections of pipes together, special methods are used, which are usually called advance penetration.
- After the formation of the drill column is completed, it is necessary to make a selection of soil from the part that crumbles into the recess during operation.
- When the pit is completely ready, it must be equipped with a reinforcement cage in order to successfully install the pile in the future.
- Next, you need to proceed to the supply of cement-sand mixture using a concrete pipe. This technology is called pile driving.
- When it becomes necessary to remove a pipe from a well, it is very important to follow the sequence.
Thus, it is clear that using cored piles using casing pipes is quite simple.
Casing pipes made of plastic
It is possible to manufacture casing pipes from plastic in such categories as:
- LDPE or PND - high or low pressure polyethylene;
- PVC - polyvinyl chloride;
- low density polyethylene - PNP.
The main characteristic is the wall thickness of such pipes, usually it does not exceed a value of 40 mm. The device of bored piles with the use of casing made of plastic has such advantages as:
- high tightness in the joints of individual pipe sections;
- high rate of corrosion resistance;
- the cost of plastic casing is much lower than metal;
- the mass of plastic products is much less;
- such material perfectly tolerates almost any chemical effects, and also resists well any other aggressive external manifestations;
- the installation speed when using plastic pipes is much higher, since they are much easier to connect.
Operational Features
One of the features concerns the case when there are groundwater of natural or industrial origin on the construction site. In such cases, it is customary to use casing only from asbestos cement. In this situation, the strengthening of the mine is also necessary. The only exceptions are those cases when the soils belong to refractory or swelling.
If at the construction site any conditions that can be attributed to the group of complex geological conditions are observed, then the use of a casing for a bored pile becomes mandatory. It is most important to comply with this rule if the area of construction is located where landslides or earthquakes, avalanches occur. Such cases are an exception in the sense that casing pipes also remain in the ground and are not removed. If a well is drilled, for example, for a well, where excess moisture pressure will be observed in the future, then the walls should also be strengthened.
Diameter selection
There are specialized catalogs in which all diameters for casing pipes for bored piles are indicated. In order to indicate the main parameters, special marking is used. An important role is played by both the external and internal diameter of the device. This allows you to use pipes that will be most suitable for the selected diameter of the pile. The parameters of the outer diameter range from 620 to 2500 mm. The inner diameter ranges from 640 to 2580 mm.
During operation, it is very important to make fairly frequent pauses in order to raise the drill and clear it of soil that clogs between the blades. In order to equip a well up to 15 meters deep, it is possible to use leased equipment for installing bored piles with casing pipes.
The cost of work
The cost of such work may vary within certain limits. The price fluctuation is influenced by several factors:
- work on project documentation;
- material used for the production of pipes;
- the width and depth of drilling, of course, also affect the cost;
- technology used for drilling;
- the geographical location of the site also affects the price;
- the number of wells, as well as the quality of the equipment used.
The main equipment that is used during operation is a drill, a persistent tripod, a rotary collar and connecting elements used to fix the pipe sections to each other. The last thing worth paying attention to is the method used for drilling. Each of them has a number of both positive and negative qualities.