Technology and organization of construction and installation works in the gas industry. Gas supply of residential microdistrict in Urengoy

Contents

Contents

1.1 Introduction

1.2 Selection of mechanisms for work execution

1.3 Calculation of Scope of Work

1.3.1 Preparatory and auxiliary works

1.3.2 Earthworks

1.3.3 Determination of dump dimensions

1.3.4 Scope of Work for Gas Line Filling and Bedding

1.3.5 Welding operations

1.3.6 Installation works

1.3.7 Gas Pipeline Test

1.4 Bill of Quantities

1.5 Conclusion

1.6 List of sources used

1.7 Attachments:

1.7.1 Installation diagram of the gas pipeline section from PK0 to PK7 +

1.7.2 Longitudinal profile of gas pipeline section from PK0 to PK7 +

1.1 Introduction

Urengoy is a large urban-type settlement that is part of the Purovsky district of the Yamal-Nenets Autonomous Okrug.

The territory of the Purovsky district is 114 thousand square kilometers, which is equal in area to Bulgaria. The area of ​ ​ the Urengoy village zone is 4248 hectares, of which 13.67 hectares, 68.52 hectares are public land, 327.48 hectares are industrial zone.

The territory of the Purovsky district has the appearance of a lowland plain, with low rises up to 150 meters high to the south. Absolute elevations range from 15-20 to 50 m. The riverbeds are weakly cut and very winding. On the watershed of the Pura and Taza rivers is the TazPura Upland of the same name. It has a character of a relatively raised dismembered plain with heights of 78-80 m.

Of the minerals, it is worth naming not only natural gas, gas condensate and oil, but also deposits of building sands, clay, gems - agate and heartland, found in the Pura Valley.

The climate of the Surah region. This is due to a number of factors, such as the position at high latitudes and the proximity of the Arctic Ocean, which is manifested in the uneven flow of total solar radiation during the year, low winter air temperatures and large annual temperature amplitudes.

The average temperature of February (the coldest month) is 22 ° The absolute minimum temperature of the district, which was recorded in Urengoy - 63 °. The average July temperature was + 9 °, the absolute maximum was + 34 °. The total solar radiation is 79 kCal/sq. see per year.

Another factor is the dependence on cyclones and anticyclones born over the North Atlantic, Central Asia and Europe.

The harsh climate and negative average annual temperatures contributed to the widespread development of permafrost. Its power reaches 300 meters and consists of two layers: the upper, modern, 15 meters thick, and the lower, relict layer, starting at a depth of 80 meters and having a power of 200 meters.

The relief of the Yamal-Nenets Autonomous Okrug (Fig. 1) is represented by two parts: mountain and plain. The flat part lies almost 90% within altitudes of up to 100 meters above sea level; from here there are many lakes and swamps. The left bank of the Ob has an elevated and crossed relief. The right-bank, mainland part is a slightly hilly plateau with a slight slope to the north. The most elevated areas of the lowland are located in the south of the district within the Siberian Uvals .

The mountainous part of the district occupies a non-wide strip along the Polar Urals and is a large mountain range with a total length of over 200 kilometers. The average height of the southern masses is 600800 meters, and the width is 2030. The highest peaks are the Kolokolnya mountains - 1305 meters, Pai-Er - 1499 meters. To the north, the height of the mountains reaches 10001300 meters. The main watershed ridge of the Polar Urals is winding, its absolute heights reach 12001300 meters and above.

The soils are peat-gleic, peat-marsh, and under the rare forests - glea-podzolic (pits).

Selection of mechanisms for work execution

Selection of mechanisms for construction and installation works on the gas pipeline arrangement is carried out in accordance with the recommendations given in [2], on reference literature [1].

Due to the great maneuverability in urban conditions, we will accept a trench for digging, an excavator with a reverse shovel on a pneumatic wheel. According to the recommendations, we choose for our conditions the following excavator for digging a trench [1, p.112]:

Full-turn hydraulic excavator on pneumatic wheel drive with reverse blade of EO2621 grade.

For backfilling of the trench, we select a bulldozer on the pneumatic run [1, p.126] of the brand DZ37 with hydraulic control on the basis of the MTZ52 wheel tractor.

Bulldozer DZ37 with hydraulic control on wheel tractor MTZ52 of class 1.4 t is equipped with rear hinged ripping teeth, which, when working forward, are drawn by the rear side on the ground, and during reverse travel they can loosen the soil. The teeth are attached to the rear wall of the dump stiffness box on the fingers and, if necessary, can be attached in a raised position. The bulldozer dump can be equipped on the sides with wideners and a brick to break into the asphalt surface. The kirk is bolted down the middle of the dump. Dump is controlled by hydraulic cylinders from tractor hydraulic system.

For welding of swivel and non-swivel joints in urban conditions, we will select a mobile electric welding converter of direct current grade PSO300 [1, p. 142], designed to supply direct current to one welding station for manual arc welding, surfacing and cutting of metals with piece electrodes, as well as to supply welding current to plants for mechanical welding under flux.

Installation of gas pipelines is carried out in two stages:

pre-assembly of pipeline elements on specialized stands in installation straps;

installation of the installation mould to the design position.

In our case, for the assembly of piping elements into the installation sections and their subsequent installation in the design position, a car crane with a lifting capacity of up to 10 tons is sufficient. Select motor crane of KS3571 grade [1, p.135].

For pneumatic testing of the installed gas pipeline, we select a light compressor unit of grade VKA26D1 [1, p. 151].

For soil compaction during filling of gas pipeline and restoration of destroyed roads the following soil compaction equipment is applicable [1, p.128]:

Tamper electric IE450 (S690A) brands.

Quantity takeoff

The construction of external gas pipelines is carried out by specialized organizations with appropriate permits and licenses, according to projects developed by design institutes.

Construction of external gas pipelines includes the following works:

preparatory work;

digging trenches for the gas pipeline;

welding and insulation of gas pipeline ;

laying of gas pipeline;

gas pipeline tests;

filling of gas pipeline.

The construction of the gas pipeline begins with the breakdown of the route. The binding of the gas pipeline axis relative to permanent landmarks (residential buildings, capital buildings, etc.) is fixed by metal pegs - repers, and on the asphalt surface - by special metal buttons. Benchmarks are installed at all angles of gas pipeline turns, in straight sections within the limits of benchmarks visibility and at points of underground communications intersection. Regardless of the instructions in the project, the points of intersection with other communications are specified on the spot with representatives of organizations operating these communications. The breakdown of the route is drawn up by an act signed by representatives of the customer, design and construction organizations.

Then, pipes in the form of isolated sections or lashes welded from several sections are brought to the gas pipeline route and laid out on sunbeds along the route no closer than 1.5 m from the brow of the planned trench. The construction site is enclosed, providing it with passages for pedestrians, crossings and detours for road transport. The imported pipe sections are welded into long-length lashes so that the joints are spaced from the intersection with underground communications by at least 1 m. The ends of the welded long-length lashes are plugged with inventory plugs and left on the eyebrow until the trench is ready for lowering the gas pipelines.

Before digging trenches in preparation, road pavements are opened, as well as pits are dug at the intersection of the gas pipeline route with intersected underground communications. To dig a trench, the width of the opening of road surfaces should be more than the width of the upper part of the trench with asphalt coating on a concrete base - by 10 cm (per side), with other road surface structures - by 25 cm (per side). Sections of gas pipeline intersection with existing underground communications are opened manually by pits to the entire trench depth in order to avoid their damage.

We open the pavements with wideners installed on the sides of the dump of the bulldozer DZ37 and a brick to break into the asphalt surface.

Underground connections opened by pits are fixed by supports or suspensions to crossbars, at that electric cables are enclosed in wooden box.

Trench digging is the most time-consuming work in the construction of gas pipelines, complicated in urban conditions by the fact that it should be carried out in a short time and on the minimum necessary working territory. The length of the working area is determined by the length of the trench, which should not be too long to allow pedestrians and transport. The width of the working area is accepted taking into account the placement of a trench, a dump for soil and an installation site on it. To reduce the width of the working territory, sometimes they organize the removal of soil to the designated places - cavaliers, followed by bringing it to fill the trench.

Trenches are dug by a full-turn hydraulic excavator on a pneumatic wheel with a reverse blade of EO2621 grade.

After the trench is opened, we clean up and align its bottom with the design elevations. At the same time, manually prepare pits for welding non-rotating joints.

The gas pipeline is laid in the finished trench using car boom cranes KS3571. In narrow street driveways, the gas pipeline is laid using tripods, winches and hoists. To lift, move and lower insulated gas pipelines, to avoid damage to the insulation, use soft slings - towels from rubberized tape.

After laying the gas pipeline lashes in the trench, centering, welding and insulation of non-rotating joints are carried out, and then tossing for the gas pipeline and filling the sinuses with sandy soil with careful compaction. For better safety of insulation, fill the gas pipeline with a ground-ground layer of 20-25 cm. At the same time, uninsulated joints of low and medium pressure gas pipelines not tested on the edge are left open for strength testing .

Correctness of gas pipeline laying according to design marks, quality of works on bed arrangement and safety of insulation shall be checked by the commission and executed by the act of hidden works.

1.3.1 Preparatory and auxiliary works

Steel electric welded straight-joint pipes are used for gas pipeline construction. Data on pipes are given in Table 1.3.1:

Total length of the gas pipeline, item m:

We will accept in our calculations that in the planned place of installation of the gas pipeline there is soil of natural humidity, and the type of soil is soup.

The type of trench, taking into account the selected soil type, is selected with the device of vertical walls.

In areas where the gas pipeline route crosses the capital road surface, it is necessary to open these surfaces before the excavation work.

Width of open pavement lane is determined by formula 1.3.1, m:

The minimum width of the trench shall be calculated from the outer diameter of the pipes, taking into account the insulation and the width of the cutting edge of the excavator ladle. In our case, the width of the trench is determined by the width of the excavator bucket and is:

l.

Then the width of the pavement lane to be opened will be:

C = 0.65 + 0.2 = 0.85 m.

The obtained width of the exposed pavement lane is entered in Table 1.3.2.

The area of the exposed road surface is calculated according to the formula 1.3.2, m2:

,

(1.3.2)

where L is the width of the crossing, m.

Data on the intersection of the capital road surface by the gas pipeline is taken from the general plan (see drawing KP.2915.306) and entered in Table 1.3.2. We substitute the obtained values ​ ​ of the width of the exposed lane of the road surface and the width of the crossed passage into the formula 1.3.2:

- for crossing No. 1 m2;

- for crossing No. 2 m2;

- for crossing No. 3 m2;

- for crossing No. 4 m2;

- for crossing No. 5 m2;

- for crossing No. 6 m2;

the obtained values are summarized in Table 1.3.2.

1.3.2 Earthworks

Digging of trenches for gas pipeline shall be performed by excavator EO2621. Trenches must be dug manually near houses or other structures, as well as at intersections with other communications. The arrangement of pits in places of welding of non-rotating joints must also be done manually.

According to the general plan, we determine the places where the work will be carried out manually; we calculate the total length of these areas. Data shall be entered in Table 1.3.3.

According to the general plan, we develop the installation diagram of the gas pipeline section from PK0 to PK7 + 59. The measuring length of the factory pipes according to GOST 1070491 shall be taken to be equal to 9 p.m. The length of the installation section according to the recommendations [2] is taken to be equal in the interval of 36 40 p.m. Based on this, we carry out the layout of non-rotating joints on the plan of the gas pipeline route, while taking into account joints in places where pipe diameters change. According to the wiring diagram, we determine the number of installation sections and non-rotating welded installation joints, we record the data in Table 1.3.5.

After laying the gas pipeline in a trench, we arrange a bed, i.e. soil is knocked out under the pipe and carefully compacted. Soil compaction is performed in layers.

After acceptance of the completed section of the gas pipeline by the commission, it is allowed to fill the gas pipeline on the accepted section.

Filling is carried out in two receptions.

First, fill the gas pipeline with a layer of soil that does not contain large inclusions for 20? 30 cm. The volume of work on filling the gas pipeline is calculated according to the formula, m3:

The soil used for backfilling remains on the edge of the trench. The minimum width of the working area depends on the volume and size of the soil dump and can be calculated according to the formula, m:

1.3.5 Welding operations

When constructing gas pipelines, it is allowed to use all types of welding that meet the requirements of regulatory documents.

During the construction of the gas pipeline section from PK0 to PK7 + 71, manual arc welding is used, since the remaining types of welding are used limited.

For the convenience of assembly of the joint for welding, external centralizers are used, consisting of separate links pivotally connected to each other like a roller-shoe chain. With the help of centralizers, we align the ends of pipes so that the cylinders forming them coincide.

A properly made seam in terms of strength and other physical properties often exceeds the quality of the metal of the pipes used, shaped parts (withdrawal, tee, transition) and products.

Arc welding of swivel and non-swivel joints of pipes at wall thickness up to 6 mm is performed in at least two layers. The thickness of the first layer should be 15-20% of the thickness of the pipe wall, the thickness of the second layer should be more than the wall thickness by 1-3 mm due to reinforcement, that is, the weld metal roller. The first layer shall ensure complete penetration of the seam root and walls and create a roller on the inside of the pipe with a height of ~ 1 mm. When the first layer of the rotary joint is applied, the roundness of the pipe is divided into 4 equal parts and the joint is stuck. The welding seam is applied to these parts in the following sequence: the electrode is installed at point A and welding goes up to point B; Then the welder moves to the other side and brews the pipe from point D to point B, after which the pipe is turned to 900 and the seam is brewed between points D and A, B and B. (see Fig. 1.3.3). The second layer is superimposed with constant rotation of the pipe along its entire circumference, but in opposite directions, which reduces the values ​ ​ of stresses in the joint. When welding non-rotating joints, all seam layers are applied from bottom to top over half the circumference of the pipe, as shown in Figure 1.3.4. [1]

For welding of swivel and non-swivel joints use mobile electric welding DC converter of PSO30 grade.

According to the installation diagram, count the number of rotary welding joints for each pipe diameter, data are entered in Table 1.3.8.

1.3.6 Installation works

Installation devices for section laying are selected according to their load capacity and weight of insulated pipe section. When determining load capacity, weight of section is distributed uniformly into two mounting devices.

Weight of mounting section is determined by formula, kg:

according to the installation diagram, for each diameter of pipes, we determine the number of installation sections and their length, by the formula 1.3.14 we calculate the weight of each section. The obtained data shall be entered in Table 1.3.9.

For the installation and suspension of single pipes and mounting sections to the load hook of the mounting crane or lifting device, various gripping devices are used, which should ensure the sturdy and reliable fastening of the pipe and the preservation of its insulation coating. The most common of these are "towel" captures.

"Towels" - soft slings - are intended for lifting and transportation operations performed during the installation of gas pipelines from steel insulated pipes. Soft slings distribute lifting forces evenly over a large area, as a result of which the insulation coating is not damaged. [1]

To lift the mounting sections we select "towels" with the following characteristics:

Brand

Lifting capacity, tn

Pipe diameter, mm

Tape width, mm

Weight, kg

MP-300

8

89 ÷ 325

200

5 kg

Assembly of pipeline elements into installation sections and their subsequent installation in the design position are carried out using motor cranes of KS3571 grade with lifting capacity up to 10 tons.

1.3.7 Gas Pipeline Test

City gas pipelines are tested twice: for strength during construction and for density after backfilling. Test results are indicated in the acts. Testing of the gas pipeline is the final stage of construction. Gas pipelines shall be preceded by purging to clean the inner surface of the gas pipeline of scale, moisture and other clogging. Blowing is carried out by sections with air pressure from 7 to 133 Pa, for which temporary gate valves are installed in necessary cases. Fouling out under the influence of air flow in the gas pipeline is a great danger, so the end of the withdrawal is directed so that there are no buildings or people near it.

The pipeline strength and density test is performed by air. Underground gas pipelines are tested for strength after sprinkling with soil. [1]

Compressor unit VKA26D1 is used for purging, strength and density testing of the installed gas pipeline.

Bill of Quantities

The scope of work for all types is calculated according to section 1.3 of this explanatory note, installation diagram and longitudinal profile of the gas pipeline section from PK0 to PK7 + 58. The results of the calculations are summarized in the BoQ (Table 1.4.1).

Conclusion

The purpose of the course project is to consolidate theoretical knowledge in the discipline "Technology and organization of construction and installation work in the gas industry."

The following calculations were made during the course project:

to determine the scope of preparatory work;

to determine the volume of earthworks;

determination of welding works scope;

to determine the scope of installation works.

The result of the above calculations is a BOQ. In the graphical part of the course project, the result is:

the wiring diagram of the section of the pipeline from PK0 to the PK7+71 (sheet A2);

longitudinal profile of the gas pipeline section from PC0 to PC7 + 71 (sheet A2).

1.6 List of sources used

Construction of urban gas supply systems. Under. Edited by A.P. Shalny. - M.: Stroyizdat, 1976

Methodological guidelines for the course project in the discipline "Technology and organization of construction and installation work in the gas industry." L.N. Kirgisarova - Tomsk2011.

SP 421012003 "General provisions for the design and construction of gas distribution systems made of metal and polyethylene pipes"

SNiP 42012002 "Gas Distribution Systems"

SPD for construction "Basic requirements to design and detailed documentation" - M.: 2002

A.A. Ionin "Gas Supply" - M.: "Stroyizdat," 1988

K.G. Kyazimov, V.E. Gusev "Construction and operation of the gas economy" - M.: Kolos, 1997

GOST 1070491 "Steel electric welded straight-joint pipes"