Pipeline laying: methods and technologies

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

The development of industry and modern urban economy is absolutely impossible without the use of pipelines for various purposes. Uninterrupted operation of heating systems for water supply, sewerage, gas, oil pipelines, etc. can only be ensured if the required technologies and standards are observed during their installation. There are many ways to assemble pipelines.

What technologies can be used

The main methods for laying pipelines are as follows:

• The open method involves the assembly of highways along supports, as well as in impassable and through collectors.
• Closed or trenchless method. It involves laying pipelines underground without first opening the soil.
• Hidden method. In this case, the pipes are pulled along dug trenches.

For the assembly of pipelines, depending on the characteristics of the transported medium, installation methods and external conditions, pipes made of different materials can be used: concrete, metal, plastic,ceramic, asbestos. In cities, the laying of water supply pipelines can be carried out in the same trench with other communications (heating mains, cable systems, etc.). In this case, the use of both trench and channel technology is allowed.

Features of the open method of laying pipelines

This technique can be used to lay pipelines for heating, water supply, sewerage, etc. The use of impassable channels for highways in comparison with the trench method has one indisputable advantage. The pipes laid in them are not subjected to soil pressure during heaving or movement, and therefore, they last longer. The disadvantage of this technique is considered to be difficult access to highways if they need to be repaired.

Laying a pipeline in through passages is more expensive. However, in this case, service companies have the opportunity to access highways without the need for excavation.

Pipes are usually laid above the ground only in disadvantaged areas of settlements, as temporary highways, etc. They can be supported by various kinds of concrete and metal structures, flyovers, walls of structures, etc.

Methods of laying pipelines in cities can be different. But in any case, the highways through settlements pull outside the zone of pressure in the soil from structures and buildings. This contributes to the preservation of the foundations in casebreakthrough. All underground city engineering communications are divided into three large groups: main, transit and distribution. The first variety includes all the main communication networks of the settlement. Transit pipelines pass through the city, but are not used in any way. Distribution highways are called highways extending from the main one directly to the buildings.

Hidden laying method

Construction of pipelines according to this technique is most often performed. The main advantage of laying pipes in trenches is their relative cheapness. However, the assembly technology in this case must be strictly observed. After all, access to pipes in this case is difficult and it should be ensured that pipeline repairs are required as rarely as possible.

Rules for work with hidden laying

Trenches for highways can be used shallow or deep. In the first case, the laying of the pipeline is carried out by 50-90 cm. When using the deep method, trenches are dug below the soil freezing. Laying of industrial pipelines can be carried out at a depth of up to 5 m. The rules for laying highways are as follows:

1. If the ground is dense, the pipes are laid directly on it.
2. When laying at a depth of more than 4 m, or if the pipes are made of not very durable material, they arrange an artificial substrate. They do the same under the condition of assembling highways in difficult hydrogeological conditions.
3. The bottom of the trenchesprepare in such a way that the pipes are in contact with it throughout. Existing voids are filled with local soil or sand.
4. If there is groundwater in the lowest places, pits are arranged to pump it out.

Hidden laying method: technology features

The technology for assembling highways is selected, among other things, depending on the pipe material used. Polymeric pipes are welded in several pieces (up to a length of 18-24 m) directly near the storage facility, and then delivered to the laying site. Here, in the summer, they are collected in a continuous thread, after which they are placed in a trench. Installation is carried out using mobile welding units. In winter, pipes are laid in a trench one at a time and connected by gluing or using rubber rings.

The construction of ceramic pipelines along the slope is carried out from top to bottom. Before installation, the pipes are inspected for chips. They are connected by a socket method with a bituminous strand seal and a cement mortar lock. Concrete pipes are laid in much the same way. In this case, a rubber ring can be used as a seal.

Asbestos-cement main pipelines with pressure up to 0.6 MPa are assembled using double-shoulder asbestos-cement couplings, and with pressure up to 0.9 MPa - using cast-iron flanges. Non-pressure pipelines are carried out using cylindrical couplings. Steel lines are laid using welding.

Trenchless method

Laying a pipeline in this way is mainly used when it is impossible to assemble using a hidden technology. For example, this is how highways are pulled under busy highways, railways, external utilities, etc. There are the following methods of trenchless pipeline laying:

• puncture;
• punching;
• horizontal drilling;
• shield penetration.

Puncture gasket

This technology is used to pull main pipelines on loamy and clayey soils. When using it, it is possible to lay pipelines up to 60 m long. This technique consists in the following:

• a steel tip is put on the pipe;
• at a certain distance from the obstacle, they dig a pit and install a hydraulic jack on supports;
• a pipe is lowered into the pit with a smaller diameter pipe inserted into it - a “ramrod”;
• produced a phased puncture of the soil.

When using this technique, the earth is not taken out. During the piercing process, it simply compacts around the circumference of the pipe.

Punching method and shield technology

These technologies are also quite often used when it is necessary to build pipelines under obstacles. Laying the pipeline using the punching method allows you to overcome obstacles up to a hundred meters long. The pipe in this case is open-endedpressed into the ground. The earth plug formed inside it is removed.

Tuning shield consists of a support, knife and tail parts. The second provides cutting of the rock and deepening of the structure into the array. The supporting part has the form of a ring and is designed to give the structure the necessary rigidity. The shield control panel is located in the tail section.

Directional horizontal drilling

This method is considered the most costly. But it has one definite advantage. Using this technology, even the most dense soils can be passed. Drilling in this case is carried out with special rods connected by hinges. Penetration can be carried out at a speed of 1.5-19 m/h. Unfortunately, this technology cannot be used if there is groundwater on the site.

Thus, the choice of methods for laying pipelines depends on the characteristics of the soil, the material used to manufacture the pipes, and the production needs. In any case, the highway assembly technologies must be observed exactly. A high-quality pipeline is a guarantee of the uninterrupted operation of industrial enterprises and urban utilities.