Organizations for the construction of a gas oil pipeline. How gas pipelines are built. Flow chart with constant rhythm

During the construction and commissioning of energy facilities, one of the most important and responsible work is the installation of a gas pipeline. The specialists of our organization have excellent theoretical knowledge and vast experience of successful work in this area. This fact, plus the availability of modern high-tech equipment, allows us to carry out work on laying gas pipelines designed for different pressure parameters and operating conditions. We build gas pipelines from various materials used in the industry.

Our clients are both small private companies and large concerns, industrial enterprises, municipal organizations. Regardless of the scale of the work, we guarantee a consistently high quality of their performance.

The cost of work on the construction of an external gas pipeline is calculated individually.
The cost of work is influenced by the method of laying, the place of work, length, complexity. Therefore, the construction of each gas pipeline is assessed separately.

Stages of gas pipeline construction:

Gas pipeline construction is a process consisting of several stages. At each stage, production work and materials used are strictly controlled for compliance with GOST, building codes and regulations, technical conditions.

1. Preparatory stage for the installation of low, medium and high pressure gas pipelines

Includes the following works:

• Obtaining a permit (opening an order) for earthworks;
• Development of PPR (work production projects);
• Construction of temporary facilities;
• Stakeout of the projected route (breakdown on the ground);
• Drilling of the soil at the intersection of communications;
• Installation of protective barriers.

2. The main stage of the gas pipeline construction

Includes earthworks: (from excavation of the route to final backfilling) and installation work on laying the gas pipeline: (from assembly to laying the gas pipeline):

• Excavation of a trench
• Cleaning the bottom of the pit
• Construction of a sandy base of the trench
• Pipeline laying, installation:

Before starting the installation procedure, a visual inspection of all pipes, insulation materials, fittings and other components used is carried out. From a batch of pipes supplied, each unit is checked. If cracks, dents, corrosion damage are found, pipes are rejected. At the request of the general contractor or the customer, in addition to visual inspection of the insulation, an instrumental method for monitoring the insulation coating can be applied in accordance with GOST 9.602-2016.
- Laying of aboveground gas pipelines, as a rule, involves the use of steel pipes. In the construction of underground gas pipelines, pipes made of steel or polymer materials are used, internal pipes are made of steel or copper. In recent years, polymer pipes have become increasingly popular. Their advantages are corrosion resistance (as a result, no anti-corrosion protection is required), and a long service life.
- Installation of gas pipelines is carried out by experienced specialists, networks are assembled from units and fittings of factory production - single pipes, sections, bends and half-bends, plugs, transitions.
Thanks to this assembly arrangement, the prompt installation of the gas pipeline with its full tightness was ensured. During the construction of steel gas pipelines, the structural elements used, as well as the dimensions of welded joints, must strictly comply with GOST, standards and rules adopted in the industry.

- The technological process of welding a gas pipeline is divided into stages:
... The pipes are being prepared for welding;
... Butt joints are being assembled;
... Single pipes are welded into sections;
... The sections are gathered in a whip.
The pipe welding methods used by our specialists are electric arc welding, gas welding, butt flash welding, welding with embedded heaters.
- Completed welded joints in accordance with the requirements of SP 42-101-2003 are checked by visual inspection, mechanical tests, physical control methods. All joints fully comply with applicable rules and regulations.
- Either single pipes (sections) are laid in the trench, followed by welding in a thread, or pre-welded long lashes.

• Tamping the pipe body with non-freezing bulk soil (sand)
• Laying of insulated satellite wire
• Pre-sanding
• Partial backfill with compaction
• Laying of yellow warning tape with indelible inscription "flammable - gas"
• Backfilling the gas pipeline
• Testing the pipeline for strength and tightness

Upon completion of the gas pipeline installation, in accordance with existing standards and regulations, strength and tightness tests are required. The internal cavity of the pipes is pre-cleaned. Individual pipes (sections) undergo a cleaning procedure immediately before being welded into the string. Upon completion of the gas pipeline laying, it is purged with air.
The specialists of our organization carry out a full range of works on testing the gas pipeline in the presence of the customer's technical supervision service and a representative of the gas industry.

• Corrosion protection

Simultaneously with the development of a project for the construction or reconstruction of a gas pipeline, the design department carries out a protection project taking into account corrosion factors. In practice, several types of corrosion protection are used, all methods are applied by our specialists before the facility is commissioned.

3. The final stage of construction and commissioning of the gas pipeline:

Upon successful completion of the required tests, the gas pipeline is put into operation. The commissioning of the object involves the implementation of the following procedures:
Preparation of executive and technical documentation, control of compliance with state standards, regulatory documents, actually performed work;
Transfer of executive and technical documentation to control and supervision bodies;
Checking the performance of work for compliance with the developed project documentation, applicable rules and regulations;

Putting the gas pipeline into operation is completed with the receipt of a positive resolution from the inspecting authorities, acceptance of the executive and technical documentation. The next stages are registration of ownership of the gas supply system, registration of documentation allowing a tie-in into a gas pipeline that is a source of gas.
After the conclusion of contracts between the Customer, the gas supplier and the organization servicing the gas pipeline and equipment, it is allowed to fill the system with gas.

They have more than half a century of history. Construction began with the development of oil fields in Baku and Grozny. Today's map of Russian gas pipelines contains nearly 50,000 km of trunk pipelines, through which most of the Russian oil is pumped.

History of Russian gas pipelines

The pipeline in Russia began to be actively developed back in 1950, which was associated with the development of new fields and construction in Baku. By 2008, the amount of transported oil and oil products reached 488 million tons. Compared to 2000, the indicators increased by 53%.

Russian gas pipelines (the scheme is updated and reflects all pipelines) are annually growing. If in 2000 the length was 61 thousand km, in 2008 it was already equal to 63 thousand km. By 2012, the main gas pipelines of Russia have significantly expanded. The map displayed about 250 thousand km of the pipeline. Of these, 175 thousand km was the length of the gas pipeline, 55 thousand km - the length of the oil pipeline, 20 thousand km - the length of the oil product pipeline.

Gas pipeline transport in Russia

A gas pipeline is an engineering structure of pipeline transport that is used to transport methane and natural gas. The gas is supplied with overpressure.

Today it is difficult to believe that the Russian Federation (today the largest exporter of "blue fuel") initially depended on raw materials purchased abroad. In 1835, the first blue fuel production plant with a distribution system from the field to the consumer was opened in St. Petersburg. This plant produced gas from foreign coal. 30 years later, a similar plant was built in Moscow.

Due to the high cost of building gas pipes and imported raw materials, the first gas pipelines in Russia were small. The pipelines were produced with large diameters (1220 and 1420 mm) and with long lengths. With the development of technologies for the natural gas field and its production, the size of the "blue rivers" in Russia began to grow rapidly.

The largest gas pipelines in Russia

Gazprom is the largest operator of the gas artery in Russia. The main activities of the corporation are:

• geological exploration, production, transportation, storage, processing;
• production and sale of heat and electricity.

At the moment, there are such existing gas pipelines:

1. Blue Stream.
2. "Progress".
3. "Union".
4. Nord Stream.
5. Yamal-Europe.
6. "Urengoy-Pomary-Uzhgorod".
7. Sakhalin-Khabarovsk-Vladivostok.

Since many investors are interested in the development of the oil production and oil refining sector, engineers are actively developing and building new major gas pipelines in Russia.

Oil pipelines of the Russian Federation

An oil pipeline is an engineering structure of pipeline transport, which is used to transport oil from the production site to the consumer. There are two types of pipelines: main and field.

The largest pipelines of the pipeline:

1. "Druzhba" is one of the major routes of the Russian Empire. Today's production volume is 66.5 million tons per year. The highway runs from Samara through Bryansk. In the city of Mozyr "Druzhba" is divided into two sections:

• southern highway - passes through Ukraine, Croatia, Hungary, Slovakia, Czech Republic;
• the northern highway - through Germany, Latvia, Poland, Belarus and Lithuania.

1. The Baltic Pipeline System is an oil pipeline system that connects an oil production site with a seaport. The capacity of such a pipeline is 74 million tons of oil per year.
2. The Baltic Pipeline System-2 is the system that connects the Druzhba oil pipeline with Russian ports in the Baltic. The capacity is 30 million tons per year.
3. The Eastern Oil Pipeline connects the production site of Eastern and Western Siberia with the markets of the USA and Asia. The capacity of such an oil pipeline reaches 58 million tons per year.
4. The Caspian Pipeline Consortium is an important international project with the participation of the largest oil-producing companies, created for the construction and operation of pipes with a length of 1,500 km. The working capacity is 28.2 million tons per year.

Gas pipelines from Russia to Europe

Russia can supply gas to Europe in three ways: through the Ukrainian gas transmission system, as well as through the Nord Stream and Yamal-Europe gas pipelines. In the event that Ukraine finally terminates cooperation with the Russian Federation, the supply of "blue fuel" to Europe will be carried out exclusively by Russian gas pipelines.

The scheme for supplying methane to Europe suggests, for example, the following options:

1. Nord Stream is a gas pipeline that connects Russia and Germany along the bottom of the Baltic Sea. The pipeline bypasses transit countries: Belarus, Poland and Nord Stream was commissioned relatively recently - in 2011.
2. "Yamal-Europe" - the length of the gas pipeline is more than two thousand kilometers, the pipes pass through the territory of Russia, Belarus, Germany and Poland.
3. Blue Stream is a gas pipeline that connects the Russian Federation and Turkey along the bottom of the Black Sea. Its length is 1213 km. The design capacity is 16 billion cubic meters per year.
4. South Stream - the pipeline is divided into offshore and onshore sections. The offshore section runs along the bottom of the Black Sea and connects the Russian Federation, Turkey, Bulgaria. The length of the section is 930 km. The onshore section passes through the territory of Serbia, Bulgaria, Hungary, Italy, Slovenia.

Gazprom said that in 2017 the gas price for Europe will be increased by 8-14%. Russian analysts claim that the volume of supplies this year will be higher than in 2016. The income of the gas monopoly of the Russian Federation in 2017 may grow by $ 34.2 billion.

Russian gas pipelines: import schemes

The CIS countries to which Russia supplies gas include:

1. Ukraine (sales volume is 14.5 billion cubic meters).
2. Belarus (19.6).
3. Kazakhstan (5.1).
4. Moldova (2.8).
5. Lithuania (2.5).
6. Armenia (1.8).
7. Latvia (1).
8. Estonia (0.4).
9. Georgia (0.3).
10. South Ossetia (0.02).

Among non-CIS countries, Russian gas is used by:

1. Germany (the volume of supplies is 40.3 billion cubic meters).
2. Turkey (27.3).
3. Italy (21.7).
4. Poland (9.1).
5. Great Britain (15.5).
6. Czech Republic (0.8) and others.

Gas supply to Ukraine

In December 2013, Gazprom and Naftogaz signed an addendum to the contract. The document indicated a new "discount" price, one third less than the one prescribed in the contract. The contract entered into force on January 1, 2014, and must be renewed every three months. Due to debts for gas, Gazprom canceled the discount in April 2014, and since April 1, the price has increased, amounting to $ 500 per thousand cubic meters (the discounted price was $ 268.5 per thousand cubic meters).

Gas pipelines planned for construction in Russia

The map of Russian gas pipelines at the development stage includes five sections. The South Stream project between Anapa and Bulgaria has not been implemented, Altai is being built - this is a gas pipeline between Siberia and Western China. The Caspian gas pipeline, which will supply natural gas from the Caspian Sea, in the future should pass through the territory of the Russian Federation, Turkmenistan and Kazakhstan. For supplies from Yakutia to the countries of the Asia-Pacific region, another route is being built - "Yakutia-Khabarovsk-Vladivostok".

Introduction

The purpose of this course project is to develop optimal technological and organizational conditions for laying the gas pipeline. Issues related to the implementation of technological processes are considered, the sequence of work and individual processes, methods of work production are established, the means of mechanization, the composition of work teams are outlined, a technological scheme for the development, movement and laying of soil is being built.

The course project consists of a graphic part and an explanatory note. The drawings show plans and sections for all types of work, and the explanatory note provides calculations and justification for the decisions made.

Initial data for design:

1. The purpose of the pipeline is gas.
2. Quarter size: a= 100 m, b= 150 m.
3. The soil is soft clay.
4. Placing the track - sidewalk.
5. Sidewalk width - 4 m, lawn - 5 m, carriageway - 18 m.
6. The nominal diameter of the pipe is 200 mm.
7. The number of pipes in the system is 2.
8. Laying type - channelless.
9. Contour marks: m1 - 62 m, m2 - 62.5 m, m3 - 63 m, m4- 63.5 m, m5 - 64 m, m6 -65 m.
10. The range of soil import is 2 km.

1. Preparatory and auxiliary work

One of the important stages of construction is project preparation.

In the preparatory period, problems are solved with the release of the plan of the building site with the preparation of the site for the site - the creation of favorable conditions for the production of work.

Preparatory work includes: replanting trees; felling, cleaning and cutting stumps; removal of the vegetation layer - the fertile soil layer at the base of all embankments and in the area occupied by various excavations and quarries should be removed and placed in dumps for subsequent use in the restoration of disturbed and unproductive agricultural lands, as well as in the improvement of sites, drainage device - water they are taken from the construction site by preliminary arrangement of temporary water-intercepting and drainage ditches, trays and drainages. To protect the construction site at the time of excavation from storm and melt water, on the upland side of the excavations, upland ditches, soil dumps or cavaliers are arranged to divert storm and melt surface water to the side; vertical layout of the site; dismantling of old communication networks; demolition of buildings; construction site fencing; creation of a geodetic base.

1. Block plan, route scheme. Transverse profile of the trench

The site plan with quarters, with contours and a diagram of the gas pipeline being laid is drawn on a scale of 1: 5000. The dimensions of the block, the width of the roadway, lawn, sidewalk are the initial data. The dimensions of residential areas are 100 × 150 m; street width - 36 m.

The contours are drawn by hand through the intersection points of the contours of the sides of the quarters. Place the axis of the track in the center of the sidewalk according to the assignment. On the site plan, we divide the route into pickets so that between the planes of the layout, the earth surface has a slope only in one direction.

At the points where the pickets are, define black marks:

where l 1 - distance from the picket to the smaller horizontal;

G 1 , G 2 - marks of contour lines;

l- the distance between the contours.

Knowing the nominal pipe diameter, D y= 200 mm, according to table. 11 we define:

• outer pipe diameter: D bunk= 219 mm;
• weight of 1 m of pipe: 31.5 kg; with bitumen-rubber highly reinforced waterproofing for gas pipelines: 38.9 kg.

Next, we select the required thickness of waterproofing. The thickness of the waterproofing (bitumen-rubber mastic (BRM) with a glass fiber reinforcement layer (VV-K, VV-G) and an outer wrap). Layer sequence:

1. Bituminous primer: NN (not standardized).
2. BRM mastic (first layer): 3 mm.
3. BRM mastic (second layer): 3 mm.
4. Reinforcing fiberglass wrap (first layer): НН.
5. BRM mastic (third layer): 3 mm.
6. Outer wrap.

Distance between pipes b 2 = 0.4 m (Fig. 1).

Rice. 1. Distances between pipelines in the channel

Δ is the minimum depth of the pipeline, Δ = 0.6 m,

The base is 0.15 m thick.

Red marks are calculated using the formula:

where і - minimum slope, i = 0.002 ‰;

L- distance from picket to picket in a straight line, m;

Calculated station elevation, m;

Elevation of the previous picket, m.

We calculate the working marks:

The calculations are summarized in Table 1.1 of Appendix 1.

Δ is the width of the trench; we take 0.9 m, because A slave (mean) < 2 м.

Trench width:

where m- slope steepness, m.

From the first estimate (Table 2.1 of Appendix 2), it follows that it is necessary to adjust the dimensions of the trench, since the calculated width exceeds the maximum allowable (the distance from the wall of the trench to the building line should be> 1.5 m):.

In this case, there is no possibility of sections of trenches with inclined slopes of the required steepness to ensure their stability, in particular, in the cramped conditions of urban development, and, therefore, they have to be torn off with vertical slopes. To prevent the collapse of the vertical walls, it is necessary to arrange them temporarily. We arrange inventory fastening of the walls of the trench of the spacer structure (Fig. 2).

Rice. 2 Spacer fastening of the trench walls: 1 - shields; 2 - racks (piles); 3 - spacers.

We calculate the cross-sectional area of ​​the trench:

We calculate the volume of the trench:

Where F 1 +F 2 - distance between adjacent pickets.

The calculations are entered in table 2.2 of Appendix 2.

1. Calculation of the volume of earthworks

Backfill volume:

where Kor- coefficient of residual soil loosening; according to table 16 Kor= 1.05 for soft clay;

Vtr- volume of pipes:

N- number of pipes;

Ltr- track length, m;

where dbunk- pipe outer diameter, m;

disol- thickness of the insulating layer, m

Excess soil volume:

Export volume:

where K nr- coefficient of initial soil loosening, i.e. an increase in the initial volume of soil after development; according to table 16 K nr= 1.3 for soft clay.

Cavalier volume:.

Shortfall:,

where - when calculating earthworks performed by mechanisms, it is necessary to take into account the shortage of soil by 10 cm to the design level. From these conditions, the amount of manual cleaning of the trench bottom is determined.

Volume of 100 m of trench:

1. Excavator and vehicle selection. Trench development scheme

The main parameters for the selection of an excavator:

• type of soil: clay, development complexity group - 2;
• maximum working depth: 2.37 m;
• shovel type: reverse;
• bucket capacity 0.32 m 3.

The minimum design width of the excavator development with this bucket:

where q k- bucket capacity;

δ bed- for clayey soils 0.15 m.

< with(0,97 < 2,67) - условие выполняется, при данной емкости ковша достигается максимальная глубина выработки (2,37 м), поэтому оставляем данный экскаватор с емкостью ковша 0,32 м 3 . Подбираем пневмоколесный гидравлический экскаватор ЕК-8 (рис. 3) по со следующими техническими характеристиками:

• weight, (t): 8.8;
• Perkins 1104C-44 engine;
• engine power (hp): 83;
• cycle duration, (s): 14;
• pressure in the hydraulic system, (MPa): 32;
• travel speed, (km / h): 20;

Digging parameters:

• handle, (m): 1.7;
• digging radius, (m): 8.07;
• digging radius at the parking level, (m): 6.7;
• kinematic digging depth, (m): 4.0;
• unloading height, (m): 5.9;
• bucket rotation angle, (degree): 173;
• maximum bucket capacity, (m 3): 0.32.

Rice. 3. Excavator EK-8

Rice. 4. Schedule for determining the estimated digging radius, m

We calculate the actual width of the base of the cavalier:

Cavalier's base:

The distance from the building line to the trench wall is 1.5 m, so the soil is exported, we do not form cavaliers (Fig. 5).

Rice. 5. Development of a trench with laying soil in a dump

The choice of transport for the removal of soil.

With an excavator bucket capacity of 0.32 m 3 and a soil delivery distance of 2 km, the carrying capacity of the dump truck will be 7 tons.

We accept a MAZ-503B dump truck with the following characteristics:

• carrying capacity of the vehicle, t: 7.0;
• body volume, m 3: 3.8;
• overall dimensions, mm (length × width × height): 5970 × 2600 × 2700;
• overall dimensions of the body, mm (length × width × height): 3280 × 2284 × 676.

Excavator performance:

where T- the duration of the shift is 8 hours;

q- the volume of the excavator bucket is 0.32 m 3;

n- number of excavator operation cycles, min -1

To n- bucket filling ratio equal to 0.85;

To in- time factor, equal to 0.63.

Number of buckets loaded into the dump truck:

where R- the carrying capacity of the dump truck is 7.0 t;

γ - soil density, 1.8 t / m 3.

Dump Truck Loading Time:

where tc.e.- the duration of the excavator cycle;

Dump Truck Cycle Time:

where l- the distance of the carriage is equal to 2 km;

ν - transportation speed, 23-25 ​​km / h;

tsmash- unloading time is equal to 2 minutes;

tm- maneuvering time is 2 minutes.

Dump Truck Performance:

Number of vehicles:

The excavator is serviced by 4 machines.

We assign a scheme for the development of a trench. Fig. 4 we determine: at the greatest And the slave= 2.37 m is equal to 5.5 m.

Unloading height on transport:

where is the height of the transport, equal to 2.7 m;

The width of the body is 2.284 m.

With end-face diagram; with lateral scheme.

In our case, we use the end scheme of the excavator movement (movement of the excavator along the axis of the trench).

Maximum development width, m:

where l p- the step of the parking lots or the length of movement (depends on the capacity of the excavator bucket).

the excavator movement pattern is selected correctly.

The length of the set of soil for full filling of the bucket, m:

where is the length of the slope.

Dangerous Turning Radius:

where is the radius of the tail section, m.

1. Earthworks technology

Before starting the development of the trench, the following work must be performed:

• clearing of the land right-of-way from stones and trees and shrubs;
• the axis of the trench and the boundaries of the soil dump were taken out and fixed on the ground;
• the necessary materials and equipment were delivered to the work area.

The alignment of the microrelief of the base path of the excavator is performed. The width of the planned strip is assumed to be 4.0 m.

After planning the base path of the excavator, the alignment points of the axis of the trench and the boundaries of loading onto the transport are restored.

The excavation of the trench is carried out with an excavator with a backhoe EK-8 along the axis of the trench by loading the soil into a dump truck. To preserve the natural structure of the base soil, the excavator does not finish the bottom to the design level by 10 cm.

A diagram of the development of a trench with an excavator equipped with a backhoe is shown in Fig. 6.

Rice. 6. Development of a trench with an excavator equipped with a backhoe

Work on a trench section is performed by a mechanized unit consisting of:

excavator driver 6 digits - 1;

bulldozer driver 6 bit - 1.

Operational quality control of work on a trench section should be carried out under the systematic supervision of the technical personnel of the construction organization and workers of the construction laboratory.

Deviations in geometrical dimensions permissible during the development of trenches are given in table. 1.

Table 1. Deviations of geometrical dimensions, permissible during the development of trenches

Table 2. Scheme of operational quality control

Table 3. Demand for machines, equipment and fixtures

1. Calculation of labor costs.

Work schedule

Technological calculations are compiled according to the calculation of labor costs and wages and are the basis for building a calendar plan. The calculation should determine the labor costs and wages of workers for the production of work for each process, as well as for the entire range of work on the construction of the gas pipeline. During the construction of a gas pipeline, the calculation includes work on excavating the soil in trenches with a single-bucket excavator, arranging trench fences from inventory shields, leveling soil areas, arranging foundations in trenches, laying steel pipelines, dismantling trench fences, isolating joints, backfilling a trench with a bulldozer, compacting soil, soil by machines.

To calculate the calculation of labor costs, you must use the reference literature.

One of the main documents of the project for the production of works is the construction schedule of the facility. On the basis of the calculated volumes of construction and installation work and the accepted production methods, the actual (according to the developed project) construction period, the sequence of conducting each type of work with mutual coordination in time, the combination of various construction processes, the composition of the link and teams, the need for machines and mechanisms are distinguished, as well as in the labor force, depending on the complexity of the work.

To start drawing up a calendar plan, you need to have the following data:

• lists and volumes of certain types of work in the order of the technological sequence of their implementation;
• types and number of construction machines and mechanisms;
• the number of workers by profession and qualifications required to perform work on schedule, taking into account the established production standards.

Calculations to determine the amount of work, labor costs, time costs and the number of workers and machines are entered in table 3.1 of Appendix 3.

1. Pipeline testing

Before testing the installed gas pipelines for strength and tightness, they should be purged in order to clean the internal cavity from scale, moisture and blockages. The method of blowing is determined by the project of the work, taking into account local conditions.

The testing of gas pipelines by the manometric method is carried out by the construction and installation organization in the presence of the technical supervision of the customer and the representative of the gas industry in two stages: for strength and tightness.

During the initial test of low and medium pressure underground gas pipelines, joints are not sprinkled and insulation is not applied. If, before laying the gas pipeline in the trench, its joints were checked at the edge of the trench by physical control methods, or if the gas pipeline is tested with a pressure of at least 0.6 MPa, then these joints of the gas pipeline are insulated during the initial strength test and sprinkled with soil.

For pipelines with a diameter of up to 200 mm, the length of the sections of gas pipelines tested for strength and tightness should not exceed 12 km, with a diameter from 200 to 400 mm - 8 km, over 400 mm - 6 km.

Gas pipelines are tested with fittings and equipment installed, but if they are not designed for test pressure, then coils, plugs or plugs are installed instead of them for the test period.

When testing gas pipelines, the following types of pressure gauges for underground and aboveground gas pipelines are used for strength - spring pressure gauges of accuracy class not less than 1.5 in accordance with GOST 2405-80 *; underground gas pipelines for tightness - spring-loaded manometers of exemplary accuracy class not less than 0.4 in accordance with GOST 6521-72 *.

Strength and tightness testing of underground and aboveground gas pipelines is carried out in accordance with the test pressure standards.

Having raised the pressure in the gas pipeline to 0.3 MPa for low pressure gas pipelines, the gas pipeline is kept under this test pressure for 1 hour, then the pressure is reduced to the norm established for the leak test,

the joints are coated with a soap emulsion, after which the gas pipeline and fittings are inspected. The identified defects are eliminated after the pressure in the gas pipeline is reduced to atmospheric and after the compressor is turned off.

The final test of gas pipelines for tightness is carried out after they are completely backfilled to the design marks. First, the gas pipeline is filled with air, and then it is kept for the time required to equilibrate the air temperature in the pipeline with the temperature of the soil. The holding time, which depends mainly on the diameter of the pipes, is taken at D y up to 300 mm - 6 h; from 300 to 500 mm - 12 hours; at D y over 500 mm - 24 hours. Then a tightness test is carried out with a pressure of 0.1 MPa for low pressure gas pipelines.

The test result is determined by comparing the actual pressure drop during the test with the calculated pressure drop.

If the actual pressure drop does not exceed the value determined by calculation, the gas pipeline is considered to have passed the test.

1. Safety engineering

The safety standards and rules that apply to construction and installation and special construction work, regardless of the departmental subordination of the organization performing these work, are contained in SNiP 3-4-80.

8.1. Safety precautions in the production of preparatory work.

When preparing a construction site for the start of work, it is necessary to strictly monitor compliance with safety regulations. The construction site must be fenced with standard shields. In addition, trenches and pits, storage areas, wells and pits must also be fenced off with dense shields. On the construction site, roads and driveways, warning signs and signal and work lighting should be installed. All workplaces should be illuminated in the evening and at night. All walkways and driveways must be constantly cleaned of debris and building materials. During the preparatory period, the issues of supplying workers with drinking water and food are resolved, sanitary facilities are arranged.

8.2. Safety precautions in the production of earthworks.

The trenches that are being worked on the streets, driveways, in the yards are fenced. Excavations must be designed with slopes as required by building codes. The edges of the grooves must be free from static and dynamic loading. When developing recesses with vertical walls, the fastening should be installed immediately after the penetration depth with vertical unsecured walls, permissible for a given type of soil, has been reached. It is necessary to install fasteners in the direction from top to bottom as the excavation is developed. When filling such recesses, the fasteners should be removed from the bottom up. The condition (stability) of slopes and fastenings should be checked every shift.

Earth-moving and transport machines should not approach the edge of the excavation closer than 0.5 m. When working in the dark, workplaces should be illuminated, and earth-moving, transport and earth-moving vehicles should have individual lighting.

It is necessary to go down into and out of the trench only by ladders with mortise steps; it is forbidden to use the spacers of the trench fasteners for these purposes. To cross the trench, use securely installed footbridges with handrails or road bridges.

When excavating the soil with an excavator, workers are prohibited from staying under the bucket and boom and working from the side of the face. Unauthorized persons may be at a distance of at least 5 m from the excavator's radius of action.

Excavators must stand on a level surface during operation. Cars are loaded so that the bucket is fed from the rear or side board. Do not carry the bucket over the cab. The "peaks" formed during the development of the soil are immediately cut off.

When working with bulldozers, it is forbidden: to move the soil up to a rise of more than 15 ° and a slope of more than 30 °, to extend the blade beyond the edge of the slope of the excavation when the soil is pushed. When working together with an excavator, the bulldozer is not allowed to be within the range of the boom.

It is prohibited to use percussion tools (crowbars, picks, wedges) in the immediate vicinity of electric cables, gas pipelines, pressure water pipelines. The soil is developed only with shovels. In the event of the discovery of underground structures not envisaged by the project, the work is suspended until additional instructions are received.

8.3. Safety precautions in the production of assembly and welding works.

Compliance with safety rules in the production of installation and welding works should ensure the safety of not only team members, but also strangers who accidentally find themselves in the work area. An ungrounded electric welding machine, bare wire, naked flame of the welding arc, careless storage of cylinders (oxygen and acetylene) and containers with an explosive mixture can cause an accident. The welder's workplace must be protected from wind and atmospheric precipitation with plywood shields, screens or tarpaulin tents. The welder must work in durable, comfortable clothing made of linen or canvas fabric. Depending on how the workplace is organized, productivity and

safety of working conditions of the welder.

8.4. Safety precautions in the production of insulation work.

Bituminous-rubber mastic is a combustible substance with a flash point of 240-300 ° C, when a small amount of mastic ignites, the fire should be extinguished with sand, felt mat, special powders, a foam fire extinguisher, developed fires - with a foam stream or water from fire monitors. When working with bitumen, it is forbidden to make a fire within a radius of 25 m from the place of work. Bitumen boilers should be located at a distance of at least 50 m from wooden buildings and at least 15-30 m from the trench. The area set aside for the installation of the bitumen boiler must be cleaned, carefully leveled and fenced off. A non-combustible canopy must be installed over the boiler. When loading the boiler, pieces of bitumen must be smoothly lowered along its walls. The boiler should be loaded no more than ¾ of its capacity. When loading the boiler and mixing the bitumen, the worker must be on the side opposite to the boiler door. In the event of a fire in the mass, the boiler is immediately closed with a lid, the firebox is stopped, and the resulting mastic is covered with sand or extinguished with fire extinguishers.

Hot mastic is fed into a trench in a tank on a strong rope with a hook and a carabiner on it. The mastic tank can only be removed from the rope after it is placed on the ground. The insulator must use personal protective equipment, overalls and safety footwear.

8.5. Safety precautions during the testing and flushing of the gas pipeline.

Workers involved in testing and flushing the gas pipeline must be pre-instructed. Before the test, duty posts should be set up so as not to allow unauthorized persons to the tested gas pipeline. A strictly limited number of persons are allowed to check gas pipelines for tightness and strength during hydraulic and pneumatic testing. Elimination of defects found on the tested, for strength and tightness of the pipeline is allowed only after relieving pressure in it. During the test, construction and installation work on the tested gas pipeline is not allowed.

Annex 1

Table 1.1. Calculation of black, red and working marks

Appendix 2

Table 2.1. Calculation of the dimensions of the trench

Table 2.1. Calculation of the dimensions of the trench after zeroing the steepness of the slopes

Appendix 3

Table 3.1 Calculation of labor costs. Work schedule

Continuation of table 3.1

Continuation of table 3.1

Bibliography

1. Veryaskina E.M., Shibakova E.N. Pipeline construction. Methodical instructions / E.M. Veryaskina, E.N. Shibakova. - Ukhta: USTU, 2009 .-- 26 p.
2. Vishnevskaya N.S. Technology of construction, assembly and procurement processes. Methodical instructions for students of the specialty 290700 "Heat and gas supply and ventilation" of the continuous form of education. - Ukhta: USTU, 2004 .-- 42 p.
3. Melnikov O.N., Ezhov V.T., Bloshtein A.A. Handbook of the installer of heat and gas supply networks. - 2nd ed., Rev. and add. - L .: Stroyizdat. Leningrad. department, 1980 .-- 208 p.
4. Soskov V.I. Installation technology and procurement work: Textbook. for universities on specials. "Heat and ventilation". - M .: Higher. shk., 1989 .-- 344 p.
5. Construction production technology / Ed. OO Litvinova, Yu.I. Belyakov. - K .: Vischa shk. Head publishing house, 1984 .-- 479 p.
6. State elementary estimate standards for construction work HPES-2001-01. Collection № 1. Earthwork, 2008. - 302 p.
7. Catalog RusPromAvto, JSC "TVERSKOY EXCAVATOR". Technical characteristics and digging parameters of the EK-8 excavator.

BLUEPRINTS

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Getting gas is only half the battle. It still needs to be delivered to consumers. Today we will show you how to build trunk gas pipelines that cross our country in all directions and together form the Unified Gas Supply System of Russia.

We filmed our photo report in August at the construction of the second string of the Gryazovets - Vyborg gas trunkline. The length of this line is 680 km (since it was built with loopings, its length turned out to be less than the length of the entire gas pipeline, which is 917 km). This gas pipeline is designed to ensure gas supplies to Nord Stream, as well as to consumers in the North-West region of Russia. The gas pipeline runs through the Vologda and Leningrad regions.

The design capacity of the gas pipeline is 55 billion cubic meters. meters of gas per year. In addition to the linear part, 7 compressor stations were built, including the Portovaya compressor station, which is a unique facility in the global gas industry. There are no analogues of such an object in the world. Its capacity is more than 366 MW, which allows pumping gas over a distance of 1200 kilometers along the bottom of the Baltic Sea.

Most of the gas pipeline runs through forests and swamps. And in the Vyborg district of the Leningrad region about fifty kilometers passes through the rocks. It must be said that, in principle, there are no easy sections during the construction of gas trunklines. Everywhere has its own nuances, subtleties and tricks. But gas pipelines cross our country in all climatic zones, from permafrost to the warm south.

When we were filming, the final stage of the construction of the linear part of the gas pipeline in the Leningrad Region was underway. We were shown two sections: the passage of a solid rock mass near Vyborg and the construction of a microtunnel under the Saimaa Canal.

Even the construction of one gas pipeline is carried out in very different geographic conditions, and we can say that every day a team of installers comes to a new place of work. Therefore, the entire construction complex must be mobile and work everywhere, providing all new running meters of the welded pipe.

If in ordinary soil the development of a trench does not cause problems, then in a swamp these works are fraught with a number of difficulties, and the development of rocks has to be carried out by drilling and blasting. For this, holes are drilled in the rock along the route of the future trench - the so-called boreholes, into which charges are laid.

Next, the trench is freed from the remnants of rock and the bottom is leveled, then, before laying the pipe, a sand cushion is made. Simultaneously with the preparation of the trench, pipes are laid along the route. By the way, these are the products of one of the most modern workshops for the production of large-diameter pipes "Height 239" of the Chelyabinsk Pipe-Rolling Plant. Gazprom also cooperates with other domestic producers - in the summer of 2012, the company signed agreements on scientific and technical cooperation with CJSC United Metallurgical Company, OJSC Severstal, OJSC Pipe Metallurgical Company and the aforementioned OJSC Chelyabinsk Tube Rolling Plant. ...

Continuing the topic of interaction with Russian pipe manufacturers, we note that Gazprom and manufacturing companies are implementing programs of scientific and technical cooperation, in which special attention is paid to the development and production of new types of pipes necessary for our company to implement projects on the Yamal Peninsula, in Eastern Siberia and in the Far East.

These people call themselves linemen - they make only the linear part of the gas pipeline, leaving gaps at the intersections of roads and utilities. Other specialists work in such areas: explosive brigades and teams of piercers. They deal with crossings under railways and highways, as well as water obstacles.

Let's take a look at the main stages of welding the linear part of a gas pipeline. In the photo you can see a mobile complex: a mobile welding column plus a system for orbital automatic and mechanized pipe welding.

It all starts with preparing the joints, which are brushed to a metallic shine with the help of an ordinary grinder.

Then a centralizer is brought to its original position - a device that centers the edges of a new pipe with an already finished section of the pipeline. With the help of expandable clamps of the centralizer, located symmetrically around the circumference, the pipes are fixed relative to each other, while the necessary gap between the edges is set, which is necessary for welding the root layer of the seam.

The prepared pipes are hung out by the pipelayer in the installation position with the help of soft slings - tapes, excluding damage to the factory insulation coating.

Pay attention to the tracks of the pipelayer - you have to work among the stones, and sometimes the metal cannot withstand.

In this place, a stream will flow over the line (which has now been taken to the side), and according to the project, pipes with thicker walls are used here.

Now the pipe is being installed and the edges are centered using the same centralizer.

After installing the pipe, the welding post is lowered onto the joint - a tent, which houses a part of the welding and auxiliary equipment, and also has individual lighting and ventilation. In addition, work in the tent can be carried out at any time of the year, preventing the ingress of atmospheric precipitation and the effect of wind on the welded joint.

At this complex, the first, root, seam is made mechanically in a protective gas environment. This method increases the welding speed by more than three times compared to manual and improves the quality of the welded joint.

After welding the root layer, the formed reverse bead is inspected from the inside, and, if necessary, individual defects are eliminated.

Areas are welded with permissible edge displacements that could not be straightened using the internal centralizer.

On the outside, the root layer of the seam is prepared for automatic welding.

Next, orbital automatic welding heads (one on each side) are installed on the joint. Welding of filling and facing layers of the seam is carried out fully automatically - the operator-welder only monitors the movement of the carriage along the joint and adjusts the penetration depth for better filling of the welded joint. Usually there is one pair of passages in each tent. There are four tents in this complex.

The gas pipeline section is ready. After completion of construction, all welds are checked by non-destructive testing methods.

Now take a break. All workers of the site live in Vyborg, and a shift worker brings them to the place of work. She also delivers them lunch and serves as a dining room.

Most of these people have been working for Gazprom for many years - they have built gas pipelines in all corners of our country. Let's not interfere with their lunch and go to another section of the construction site.

We are going deep into the Karelian Isthmus. The next section is the construction of a microtunnel under the Saimaa Canal near the Pälli lock. Before the Saimaa Canal, this gas pipeline crossed the river in this way only once - in 2009, the builders of the Gryazovets - Vyborg gas pipeline built a microtunnel under the Neva.

The microtunnel under the canal is being constructed using the Herrenknecht tunnel boring machine. Everything here is like in a large tunnel construction, only the jacks, which push the shield forward, are not on it, but in an assembly chamber 21 meters deep. The operator sits in a special booth on the surface - there is simply no place for him on the shield.

The tunnel consists of prefabricated reinforced concrete pipes with a length of 3 m and an outer diameter of 2.5 m.

The lining design is designed for a combination of maximum ground pressure loads and is impervious to water. Since the pipe sections are pushed through, a special lubricant is injected between the lining and the rock, into the construction gap, which facilitates the advancement of the finished tunnel.

The shield itself is a whole underground ship, which is equipped with various equipment. Including - navigation, for conducting driving along a given route.

The jacking station, located in the starting pit, cannot provide pushing through the entire length of the tunnel, which is 250 meters. Therefore, after 50–70 meters, additional jacking sections are installed, which press the lined shield.

The laser theodolite, installed in the assembly chamber, provides accurate guidance of the shield along the route. The beam hits a special plate in the face, and by the deflection of the beam on it you can see in which direction the complex has deviated.

On the other bank, a working string of the gas pipeline has already been welded and prepared for rolling into the microtunnel.

Within the framework of our photo reportage, it is impossible to tell in detail about all the features of the construction of gas pipelines. But we have tried to reveal some of the secrets of this difficult work. Thanks to Gazprom invest Zapad LLC for their help in organizing the filming. Until next time.