The installation technology of external pipelines largely depends on their purpose and type of laying, pipe material, their diameter, wall thickness, pipe length, the presence of ready-made insulation on them and its type (or lack of it), as well as on the provision of construction with installation elements (pipe sections, lashes) and other conditions.
Installation of pipelines from any type of pipes (or their sections) is associated with the need to connect them into a continuous thread. Pipelines on the route are assembled (mounted) from individual elements (pipes) of relatively short length, and therefore a large number of joints have to be sealed or welded. This slows down and increases the cost of laying pipelines. Somewhat facilitates the laying of pipelines, the preliminary enlargement of pipes into links or sections of two or three and more pipes.
The laying of pipelines consists in the installation and assembly of assembly units on the route - pipes (or their sections, lashes), fittings, compensators and fittings - in the design position. At the same time, the larger the mounting unit, the fewer mounting joints and the easier it is to assemble pipelines. The nodes are completed and tested, as well as covered with a layer of insulation or painted at pipe procurement bases. The industrial technology of laying pipelines provides for the centralized procurement of mounting elements and assemblies, their delivery in finished form to the route, preliminary preparation of foundations and supporting structures to laying, on-precise assembly of pipelines.
The composition and sequence of work processes when laying pipelines depend on the type of pipes used (metal and non-metallic), as well as on the conditions for their laying (in cramped urban or field conditions, on flat or rough terrain, with or without natural or artificial barriers, etc.).
Work during the laying of pipelines is usually carried out in several stages, performed sequentially: checking the quality of pipes; lowering pipes into a trench; centering and laying them in a given direction and slope, fixing pipes in place; sealing joints with checking their quality; testing and acceptance.
The quality control of pipes is usually carried out twice - at the manufacturing plant (according to the established methodology, sometimes with testing them on the bench) and directly on the route before they are laid in the trench. On the route, almost all incoming pipes are subject to inspection and verification of their quality. This is extremely necessary, because the use of at least a few or even one low-quality pipe during the installation of a pipeline, especially a pressure one, will lead to breaks and accidents at the place of their installation. It is very difficult to eliminate them, since it requires stopping the operation of the conduit and digging trenches. In case of accidents on water conduits made of bell-shaped cast-iron or reinforced concrete pipes, replacing a low-quality pipe is very difficult. If in such cases it is impossible to correct the defects of a low-quality pipe in the trench, it is necessary to destroy it (which is also not easy) and remove it, and in its place to lay an “insert”, most often from a steel pipe, since it is almost impossible to lay the same socket pipe. If it is possible to correct the defect and put the pipeline into operation, then the “insert” will always be a weak point due to the rapid corrosion of the steel pipe.
On the route, incoming pipes are accepted according to the documents (certificates, passports) of manufacturers confirming their quality. However, defects may occur in pipes due to improper loading, transportation and unloading. Therefore, before laying in a trench, the pipes are carefully inspected, their actual quality is checked and they are rejected if serious and irreparable defects are found. It is not allowed to lay pipes with cracks, chipped edges and sockets, large deviations from the circumference, i.e. with ovality, and other serious defects. The surface of the rubber cuffs and rings used for pipe joints should be smooth, without cracks, bubbles, foreign inclusions and defects that reduce their operational properties.
Pipes are lowered into the trench with the help of cranes, as well as special lifting devices. Only light pipes (small diameters) are lowered manually, using soft ropes, panels, etc. It is strictly forbidden to dump pipes into the trench. Lowering pipes into a trench with gentle slopes without fastenings is relatively easy, the lowering efficiency depends only on right choice pipe laying schemes and type of erection crane. It is more difficult to lower the pipes into the trench in the presence of fasteners with transverse struts. At the same time, pipes are laid with sequential removal and installation of spacers. All this slows down and complicates the process of laying pipes, increases its labor intensity and lengthens the construction period. To speed up and secure this process, large-sized fasteners with vertical shields, horizontal girders and spacer frames are used, located every 3-3.5 m.
Pipe laying is carried out according to two schemes. In the first scheme, the process is performed by two threads. First, the pipe-layers, using a crane, lay the pipe on the bottom of the trench and continue to work on the final alignment and its temporary fixing, and then the installers, using a compressor and pneumatic hammers, caulk the pipe joints. In the second scheme, the process is performed in three streams using two taps. Moreover, one of them lowers the pipe and continues to work with a link of installers to align and temporarily fix the pipe, and the second duplicates all these processes for laying the next pipe (second stream); the third flow for caulking (sealing) of pipe joints is performed as in the first scheme. Light pipes are lowered into trenches with fasteners with the help of small-scale mechanization or manually. Pipes or sections should be lowered with strict observance of safety rules.
Pipe laying in a given direction and slope (figure below) between two adjacent wells is carried out mainly along portable (running) sights, beacon pins or with the help of a level. Running sights are used when cleaning the bottom of the trench to the design mark. When laying a pressure pipeline on the cleaned bottom of the trench, the top of the pipes is leveled (levelled), for which purpose sights without protrusions below, installed on the top of the pipes, are used. Therefore, the length of such a sight is reduced by the value of the outer diameter of the pipes.
Laying pipes in a given direction and slope
1 - cast-off; 2 - constant sight; 3 - running sight
For laying gravity sewer pipes according to a given slope, a running sight is used, which has a protrusion glued at a right angle on the bottom of the heel. When laying pipes, the protrusion sight is installed vertically on the pipe tray. The pipe is considered to be laid along a given slope to the design marks if the top of the running gear and two permanent sights are in the same plane visible to the naked eye. The straightness of pipe laying is checked by plumb lines suspended on an axial wire (mooring). After installing cast-offs and half-checks with the help of a level, the marks of the shelves are determined at the ends of the laid area.
The line connecting the points between the centers of the permanent sights on the cast-offs has the same slope as the slope of the pipeline. This line is called the line of sight. A template with a marked axis of the pipeline is inserted into pipes of large diameters, which facilitates their laying in a given direction. To speed up the work, inventory metal portable cast-off sights are used. For more accurate observance of the design slope of the pipeline tray, a visual method of an inclined beam of a level or a laser beam (sight sight) is used. With the latter method, a laser level is used, which is installed at the beginning of the site.
Gravity-flowing pipelines along a given slope can also be laid using a level. The correctness of laying the pipeline in a given direction and slope is finally checked before filling pipes and wells by leveling the bottom of the pipe and well trays, i.e. perform executive shooting. The difference in marks between the bottom of the wells and the tray at individual points of the pipeline should not differ from the design by more than a construction tolerance. The straightness of the pipeline between the wells is checked using mirrors that reflect the beam along its axis.
Pipes are fixed in place after they are laid, either by powdering with soil, or by using wedges (for example, when laying heavy pipes of large diameters on concrete bases).
Sealing of joints is carried out when installing pressure and non-pressure pipelines from short concrete, reinforced concrete, cast iron, asbestos-cement and ceramic pipes (socket or smooth on coupling joints). The joints of pressure pipes are usually sealed with rubber rings or cuffs, and gravity pipes - with a tarred strand, asbestos-cement mixture, etc. (picture below). The joints of steel pipes are welded, and plastic pipes are welded or glued.
Tightness and watertightness of socket joints cast iron pipelines are achieved by sealing the socket gap with a hemp tarred or bituminized strand, followed by a lock made of an asbestos-cement mixture that keeps the strand from being squeezed out by hydraulic pressure. Sometimes cement mortar is used instead, and in exceptional cases, lead. AT recent times sealants are used. When sealing joints with self-sealing rubber cuffs, no locks are required.
Joints of reinforced concrete pipes
a, b - socket; in - folded; 1 - smooth end of the pipe; 2 - asbestos cement; 3 resin strand; 4 - bell; 5 - cement mortar; 6 - rubber rings; 7 - cement mortar or asphalt mastic; 8 - grouting with cement mortar
Seal of socket joints with a strand. A hemp strand is inserted into the bell slot until the bell stops at such a depth that there is room for the lock device. Since the thickness of the bundle from the strand is somewhat greater than the width of the socket slot, it is pushed into the joint with the help of a caulk, with which the bundle is inserted into the annular gap, first by hand, and then with strong hammer blows (during hand chasing). During mechanical chasing, the tourniquet is compacted with a pneumatic tool. To create the required tightness of the joint, 2-3 bundles are usually laid in the slot, moreover, so that their overlaps do not coincide along the circumference. After sealing the joint with a strand, an asbestos-cement lock is installed, laying the asbestos-cement mixture into the gap in layers-rollers (3-4 layers each) and compacting with chasings, striking them hard with a hammer. The sealed joint is covered for 1-2 days with wet burlap, which creates favorable conditions for setting and hardening of the asbestos-cement mixture.
Sealant mastics are used to seal butt joints of cast-iron socket pipes when laying pressure sewer pipelines with a maximum working pressure of up to 0.5 MPa. Most often, polysulfide sealants are used from sealing and vulcanizing pastes, to which asbestos or rubber crumbs are sometimes added. Mastics-sealants are prepared at the place of work 30-60 minutes before their use. Joints are sealed using syringes with manual or pneumatic extrusion of mastic or pneumatic installations. The sealant is introduced into the socket gap using a nozzle, which is attached to the tip of the syringe or hose of the pneumatic installation.
1. TYPES OF NON-METALLIC PIPES AND THE ADVANTAGES OF THEIR APPLICATION
For laying water supply and sanitation networks, it is recommended first of all to use non-metallic pipes, given their advantages over metal ones. The main disadvantage of metal, especially steel, pipes is their fragility during operation due to their corrosion. The various measures currently used to protect pipes from corrosion only slow down this destructive process, but cannot completely stop it. The rate of destruction of the walls of steel pipes due to corrosion sometimes reaches 1 mm of wall thickness per year, and if we keep in mind that pipes with a wall thickness of about 8-10 mm are used for the construction of water supply and sanitation systems, then we can calculate a rather low service life of steel pipes, which and confirmed in practice. And this is without taking into account the impact on pipes of electrocorrosion from the impact of stray currents formed near the routes of electric transport (electrified railways, tram, trolley bus, etc.) or near high voltage power lines. These stray currents cause so-called "pitting" corrosion, as a result of which through holes are formed in the pipe, which disable water pipes in a very short time. Although there are ways to protect pipes from electrocorrosion, it is not always possible to completely prevent such destruction of steel pipes.
The second equally important disadvantage of steel pipes when used in water supply systems is that during operation, over time, they “overgrow” with deposits inside, the roughness of the inner walls of the pipes increases and, accordingly, hydraulic resistance increases, and as a result, the throughput of water conduits decreases. An attempt to restore it by increasing the pressure by replacing pumps pumping station to more powerful ones, often leads to ruptures in pipeline networks and shutdown of water consumers. A lot of money, labor and material resources are spent on the elimination of accidents.
In addition, in the case of the use of steel pipes for water supply systems, and sometimes for sanitation, there is an irrational use of scarce metal, from which it would be possible to make components and parts of various machines and mechanisms, instead of burying it in the form of pipes in the ground and dooming it to a relatively rapid destruction by ground and electrocorrosion.
Considering all this, Gosstroy of the Russian Federation decided on the primary use for water supply and sanitation networks various kinds non-metallic pipes that do not corrode and do not grow inside.
Assortment of non-metallic pipes used in plumbing construction, includes their various types, including: ceramic, asbestos-cement, concrete and reinforced concrete, polyethylene, vinyl plastic, etc. Since the range of non-metallic and metal pipes is given in special reference books (see reference list), in this textbook it not given.
2. INSTALLATION OF CERAMIC PIPING
Ceramic pipelines mainly serve the purposes of drainage and are non-pressure, i.e. gravity. Therefore, when laying such pipes, the requirements for laying them exactly along the design slope are of particular importance.
Before laying, ceramic pipes delivered for construction are subjected to acceptance and quality control. At the same time, make sure that the pipes have round shape section (ovality of the trunk and the socket of the pipe should not exceed the established limits). They must be straight along the entire length, without cracks and spalls. The end planes of the pipes must be perpendicular. Pipes with hard-to-remove defects are rejected.
Pipeline laying. Installation of ceramic pipelines is carried out both in separate pipes and in enlarged links (sections) in two, three, five pipes with overall length sections no more than 8 m. Pipelines are laid from the bottom up along the slope, starting from the manhole with sockets against the flow of the waste liquid (see Fig. 18.5).
Pipes are laid on a prepared and carefully planned base in compliance with a given slope along the running sight. The first pipe is laid on the half-shell (base) of the manhole with the socket up, i.e. "from the well." Having securely fixed the first pipe, the subsequent ones are laid, connecting them with the help of sockets. The correctness of the slopes is checked with a level, and the straightness of the axis in horizontal plane -
cord. The trays of the laid pipes must match and not form ledges. The lowered pipe is led with a smooth end into the socket of the laid pipe, leaving a gap of 5-6 mm for pipes with a diameter of up to 300 mm and 8-9 mm for pipes of a larger diameter. Butt joints of pipelines made of ceramic pipes are sealed with a hemp resin or bituminous strand, followed by a lock made of asphalt mastic, cement mortar or asbestos-cement mixture. The strand is wrapped around the pipe at least two times, and then sealed with a caulk (without hammer blows). At the same time, she must take 1/3-1/2
socket (Fig. 19.1, a), and the rest of it is filled with mastic. The mastic delivered to the place of work is heated to a temperature of 160-170°C before pouring. For the convenience of filling joints, special metal clips are attached to the pipes (Fig. 19.1, b) consisting of two hinged halves. The clip is lubricated with a thin layer of clay (so that the mastic does not stick) and is installed on the pipe close to the socket. The joint is poured without interruption through the leter on one side, so that air comes out on the other. After the mastic has cooled in the joint, the clip is removed. An example of a pipe joint with cement mortar is shown in fig. 19.1, in.
Laying pipelines in sections. To speed up the process of laying pipes in a trench and sealing their joints, they are pre-assembled into links (sections) of two, three and five pipes. Laying links of two or three pipes with a diameter of up to 250 mm can be done manually. When laying pipe links of large diameters, jib cranes and special traverses are used, which ensure the horizontal position of the links when lowered.
To speed up work on sealing joints when assembling links on a route or laying individual pipes in a trench, sometimes conical rings of asphalt mastic are attached to ceramic pipes in advance on the inner surface of the socket and on the outer surface of the other end of the pipe (Fig. 19.1, e). Before joining such pipes, the asphalt rings in the socket and at the ends of the pipes are covered with molten hot bitumen or liberally lubricated with some kind of solvent (gasoline, benzene), which softens the surface of the mastic rings. Due to the conical shape of the cast asphalt rings and the softness of their surface, pipes can be freely connected using the so-called cold method. After evaporation of the solvent and hardening of the softened mastic, a strong and hermetic pipe joint is obtained. General scheme the laying of the pipeline from ceramic pipes is shown in fig. 19.2.
3. MOUNTINGASBESTOS CEMENTPIPELINES
Acceptance and quality control of pipes. Pipes must be supplied by manufacturers as a set with couplings and rubber sealing rings. All pipes and couplings, upon receipt at the on-site warehouse, must be carefully checked and, if defects are found, rejected. Only those pipes, couplings and other connecting parts that have been inspected and accepted are delivered to the installation site.
Pipe layout along the trench before installation is carried out at a distance not closer than 1 m from its edge. Pipes with a diameter of up to 150 mm can be laid out on the route in stacks up to 1 m high, located at a distance of no more than 100 m from each other. Couplings are also laid out in stacks. Pipes of large diameters are delivered directly to the laying site and laid out on the trench berm in such a way that during pipe-laying operations there is no need for their additional movements along the trench.
Installation of pressure pipelines operating pressure up to 0.6 MPa is carried out using double-shoulder asbestos-cement couplings and sealed with rubber O-rings, and for pressure up to 0.9 MPa - using the same couplings and rubber rings or cast-iron flange couplings with rubber rings. When installing asbestos-cement pressure pipelines for pressures up to 1.2 MPa, the pipes are connected only on cast-iron flange couplings with rubber rings.
Installation of pipelines from pipes of small diameters(up to 150 mm) are mainly carried out manually with lowering them, as well as connecting parts to the bottom of the trench without any devices, if its depth does not exceed 3 m. into the pipe. Pipes with a diameter of 200-300 mm are transferred from stacks and lowered to the bottom of a shallow trench on straps, and with a trench depth of more than 3 m and fastenings, using a rope or a soft cable threaded through the pipe. Pipes with a diameter of more than 300 mm are laid as close as possible to the edge of the trench, after which they are rolled up to the edge and lowered using automobile or pneumatic wheel cranes (Fig. 19.3, a). In order to speed up the installation of pipes of small and medium diameters, before laying them, they are enlarged in sections of several pieces (up to four), and then they are lowered into the trench by a crane using special traverses (Fig. 19.3, b), excluding the possibility of leakage of coupling butt joints.
Installation of pipelines on asbestos-cement double collar couplingsmax with rubber O-rings produced in this order. First, a coupling and a rubber ring are put on the end of the previously laid pipe, and a second rubber ring is put on the end of the attached pipe to be laid. The coupling is put on so that its wider edge (with a working beveled shoulder) faces the joint. After the coupling and the rubber ring are put on, the pipe to be laid is moved close to the previously laid one (Fig. 19.3, i) and they are centered. The centered pipes are fixed with a powder of soil in the middle part, and then at the ends of the pipes, the places for installing the rings are marked with chalk before and after the installation of the joint is completed (Fig. 19.3, in). Couplings are mounted using special devices - a lever jack (see Fig. 19.3, e) or, if more force is needed, a screw jack and a screw tensioner(see fig. 19.3, and). The main stages of installation of a pipe coupling are shown in fig. 19.3, in-d. The correct position of the rubber rings after mounting the coupling is checked with a template or ruler. Rings should be located behind the working shoulder.
Installation of pipelines on asbestos-cement couplings CAM with rezine self-sealing rings of figured section has recently become widespread. Installation of pipes on CAM couplings is carried out in two ways. At the first (Fig. 19.4, a, 6) the sleeve is pushed onto the pipe to be laid up to the mark made on this pipe at a distance (L-C) / 2 from the end of the pipe, where L-
coupling length, C - the size of the gap between the pipes (Fig. 19.4, a),
then, using a mounting device, the pipe together with the coupling is pushed towards the laid pipeline until the end of the last laid pipe enters the coupling to a depth (L-C) / 2 (Fig. 19.4, b). In order to prevent the coupling from moving during installation, a persistent (portable) clamp is installed at its end. In the second method (Fig. 19.4, c, d) the sleeve is pushed onto the pipe being laid for its entire length (Fig. 19.4, c), and then the pipe is centered with the raceway laid and, using a mounting device, the sleeve of the pipe being laid is moved to the laid pipe up to the mark (L-C) / 2 on it (Fig. 19.4, G).
A - installation of individual pipes; 6 - installation of sections of several pipes by a crane using a special traverse; in, G, d - stages of installation of a coupling pipe connection (c - marking the joint and the initial position of the first rubber ring; G - intermediate stage of installation and initial position of the second ring; d - joint in the mounted state); e - lever tension jack; g - screw jack; 1 - pipes; 2 - double collar; 3 - sling; 4 - crane hook; 5 - tap; 6 - traverse with soft towels; 7 - the first rubber ring; 8 - second ring; 9 - places for embedding with cement mortar; 10 - bed with clamp; 17 - levers; 12 - traction; 13 - captures; 14 - spacer bar; 75 - tightening screw; 16 - lever; 17 - body; 18 - screws; 19 - plank; 20 - clamps; 21 - paws |
With these two installation methods, the sleeve can be initially put on and on the laid pipe. To ensure the required clearance between the pipes to be connected, a portable rod is used (Fig. 19.4, e) removed from the pipe after the installation of the joint. For the installation of butt joints of asbestos-cement pipes, along with those shown in fig. 19.3, and a lever jack is also used with a screw jack (Fig. 19.4, e) and lever-rack fixture (Fig. 19.4, g). In order to mechanize this process, a special device is also used that captures and lowers pipes into the trench, as well as joining them using CAM couplings. The device is a replaceable attachment to a single-bucket excavator and can be used to install pipes with a diameter of 300-500 mm. Attached equipment to the tractor "Belarus" of the "mechanical arm" type is also effective, which grabs the pipe with the coupling put on, lowers it to the bottom of the trench, centers and pushes the coupling onto the previously laid pipe.
The device for mounting coupling and socket pipelines (Fig. 19.5) is made in the form of a frame suspended from the crane boom with an end-controlled cylinder placed in its middle part, an end gripper for the pipe supply and at the ends - jaw grippers of the pipe and pipeline. Each of the grippers is a two-arm levers pivotally attached to the frame and a power cylinder acting on them.
The crank mechanisms, which receive movement from the power cylinders, are fixed on the frame.
To ensure centering, centering channels are attached to the frame longitudinally from below, interacting with the pipeline and pipe with the feathers of their shelves. For preliminary orientation of the device with a pipe relative to the pipeline, brackets mounted on the frame are used.
Installation of pipelines on cast-iron couplings with rubber rings of round and trapezoidal section produced in compliance with the rules for flange connections, i.e. by gradually tightening the nuts located at the ends of mutually perpendicular diameters so that the flanges do not skew. After marking, one flange, one rubber ring and a coupling sleeve are put on the laid asbestos-cement pipe. Before laying the next pipe, a flange and a rubber ring are also put on it, and then, after laying it on the bottom of the trench, they proceed to the assembly of the joint. The degree of rubber compaction is regulated by the tension of the bolts when tightening the nuts in the prescribed manner.
Installation of non-pressure pipelines are carried out using non-pressure asbestos-cement pipes and cylindrical couplings. At the same time, a cylindrical coupling is first put on the previously laid pipe, having previously marked its actual position after assembling the joint, at each end of the pipes to be connected. The pipe to be laid is lowered into the trench and moved to the already laid pipe, leaving a gap as with double-shoulder couplings, after which it is centered and calibrated according to the sight, cord and plumb line. Next, at the end of this pipe, a detachable wooden pattern, on which the sleeve is put on, so that its middle is at the joint, and the template enters the sleeve for half its length. A hemp resin strand is placed in the gap between the coupling and the previously laid pipe and compacted with caulking. The rest of the joint gap is sealed with asbestos-cement mortar. After sealing half of the joint, the template is removed and the second half of the joint is sealed from the side of the newly laid pipe. When laying non-pressure pipelines on cylindrical couplings, the pipes are connected to the seal with asphalt mastic or cement mortar without chasing, but to obtain a joint of increased strength, cement or asbestos-cement mortar is caulked.
4. INSTALLATION OF CONCRETE AND REINFORCED CONCRETE PIPING
Concrete and reinforced concrete pipes are laid on a natural or artificial base. Joints of pressure pipes (bell-shaped or coupling) are sealed with rubber sealing rings, and non-pressure (bell-shaped or seam) -
resin or bituminous strand, asbestos-cement or cement lock, as well as asphalt mastic. Before laying pipes in a trench, they, like couplings, are subjected to an external inspection during acceptance to identify defects and check dimensions.
The article was prepared and submitted digitally by the company
Concrete and reinforced concrete pipes are laid out along the trench different ways(perpendicular to the trench, at an angle, etc.), the choice of which depends on the type and load capacity of the cranes used.
Installation of pressure pipelines. Pressure pipelines are mounted from socket and smooth reinforced concrete pressure pipes on coupling joints, which diversifies the technology of their laying.
Installation of pipelines from socket pipes are carried out in the following sequence: delivery of pipes and laying them out along the trench, feeding them to the laying site, preparing the end of the pipe and installing a rubber ring on it; introducing it together with the ring into the socket of the previously laid pipe; giving the laid pipe the design position - final sealing of the joint; preliminary testing of the finished unfilled section of the pipeline (and for pipes of large diameters, only butt joints); backfilling of this area; his final test.
The installation of pipes is carried out by jib cranes, and the pipes from the berm of the trench are fed with sockets forward along the installation and always against the flow of liquid. Before laying the first pipe in at the beginning of the route, a concrete stop is installed, which ensures a stable position for the first two or three pipes when they are connected into a socket. The recommended layout of mechanisms, assembly workers and pipe layout during pipeline installation is shown in fig. 19.6, a. When laying the pipe, first, according to the template, the depth of its insertion into the socket of the laid pipe is marked on its smooth end. By installing the crane in the middle of the pipe to be laid and slinging it with a semi-automatic gripper (Figure 19.6, d, c, e) or with the help of slings, or a traverse, the pipe is fed into the trench (Fig. 19.6, d,e).
A - a general scheme for organizing work (T -1, T -2, T -3, T -4, T -5 - jobs for pipelayers); b - marking the smooth (sleeve) end of the pipe with a template; a, d - slinging the pipe and lowering it into the trench using a tong grip; d - insertion of the smooth end of the pipe into the socket; e - reconciliation of the position of the pipe in the plan according to the landmarks; g - pipe centering; h - inventory pole with a plumb line; and - stretching device; 1 - pipes; 2 - tap; 3 - trench; 4 - tick grip; 5 - laid socket pipe; 6 - stacked pipe; 7 - pits; 8 - stairs; 9 - fixed sights; 10 - portable (running) sight; 11 - inventory stakes; 12 - tension screw; 13 - beam; 14 - thrust; 15 - spacer |
At a height of 0.5 m from its bottom, the lowering of the pipe is stopped and a rubber ring is put on its smooth end, after which it is led into the socket of the previously laid pipe and lowered onto the prepared base. In this case, special attention is paid to centering the spigot end of the introduced pipe with a rubber ring relative to the lead-in chamfer of the socket of the previously laid pipe.
To align the position of the pipe being laid, a running sight is supported on its tray and then they make sure that the top of this sight is on the common line of sight with two fixed sights on the cast-offs (Fig. 19.6, e, g). After aligning the pipe vertically, the grip is removed from it, the crane is released to install the next pipe and proceed to align the position of the pipe in the plan. For this purpose, inventory poles are installed along the plumb line (Fig. 19.6, h): one of them at the end of the pipe being laid, and the other at the previously laid one. According to the fixed pole installed in the well or on the mounted section of the pipeline, they check the correct laying of the pipe in the plan (Fig. 19.6, e). If necessary, it is shifted in the right direction.
In conclusion, using a tensioner (Fig. 19.6, i), the smooth end of the pipe is inserted into the socket of the previously laid one, while monitoring the uniformity of rolling the rubber ring into the socket slot. At the same time, the end of the sleeve end must not be pushed into the socket until it stops ; a gap must be left between them (for which marking is done), and for pipes with a diameter of up to 1000 mm - 15 mm, and for pipes of large diameters - 20 mm. Having connected the pipes, remove the tensioner and knock the pipe from the sides with soil to a height of 1/4 of its diameter with its layer-by-layer compaction with manual rammers.
When installing pipelines from socket iron concrete pipes
the most time-consuming operation is the introduction of the sleeve end of the pipe with a rubber ring into the socket of the previously laid one. To facilitate it, various devices, devices and mechanisms are used. In particular, two-three-cable external tensioners are used (Fig. 19.7, a, b), rack and hydraulic jacks (Fig. 19.7, in), internal tensioners, lever and gear winches (Fig. 19.7, d, e) bulldozers and excavators (Fig. 19.7, e, g).
For the installation of pipes with a diameter of 500, 700, 900 mm, a universal hydraulic device is also used (Fig. 19.7, and),
which is fixed on the pipe, and then lowered into the trench with it. After checking the accuracy of centering the pipe and the correct location of the rubber ring, the pipe is joined to the pipeline under the action of the stroke of the hydraulic cylinder.
When choosing a pipe installation method, take into account the presence necessary equipment and mechanisms, as well as the conditions for the construction of the pipeline. Installation of pipes using a bulldozer (Fig. 19.7, e) can be done if the bulldozer is used when planning (cleaning) the bottom of the trench, i.e. when these two operations are combined. Installation of pipes with a diameter of 1000-1200 mm in trenches with a bottom width of 2.2 m is carried out using a D-159B bulldozer (Fig. 19.8). For the installation of pipes of small diameters (up to 500 mm), the Tsentrospetsstroy trust manufactured a small-sized bulldozer based on the T-548 tractor with a blade width of 1.25 m. The method of installing the pipeline using an internal tension device is recommended for pipes with a diameter of 800 mm or more
Installation of the pipeline using an excavator bucket (see Fig. 19.7, and) lead when laying pipes in water-saturated soils or in cramped urban construction conditions, when the trench is torn off as the pipes are laid, and an excavator located nearby is used to install them by turning the bucket.
The means used for mechanization of the installation of reinforced concrete and concrete pipelines depend mainly on the type of butt joint and the diameter of the pipes. The type of butt joint determines the technical requirements for installation equipment, and the diameter of the pipes and the dimensions of the trench - possible schemes accommodation mounting equipment and the resulting technological schemes for the production of installation work.
Main technical requirements to the equipment for mounting pipes on rubber sealing rings are: ensuring the alignment of the pipes and creating the necessary axial force for their joining. When installing pipes with a socket-screw connection, it is additionally necessary to ensure that the pipe being laid is screwed into the previously laid pipe. For the installation of pipes with caulking of butt joints, mechanized compaction of fibrous materials in the socket gap should be provided.
Installation of concrete and reinforced concrete pipes Currently, they are mainly carried out according to two technological schemes. In the first case, attachments are used to the pipe-laying crane to perform all operations: capturing the pipe on the berm and lowering it to the bottom of the trench, centering the pipe being laid to the laid section of the pipeline and joining the pipes. The second scheme provides for the performance of centering and docking operations by a base machine moving along the bottom of the trench with appropriate equipment. Each of these schemes has its own areas of application, due to the length and diameter of the pipes and the width of the trench.
Existing Methods installation of reinforced concrete pipes (especially large diameters of 1000, 1200 mm) do not provide accurate alignment during installation of the laid and previously laid pipes. Usually, the laid pipe is supported on weight by a hoisting mechanism, and another mechanism (tractor, excavator) creates a longitudinal force that ensures that the smooth end is inserted into the socket of the laid pipe. At the same time, as experience shows, it is very difficult to provide the same annular gap between the surface of the smooth end of the pipe and the inner surface of the socket at the joint, due to which the rubber ring located in this gap is not clamped uniformly along the perimeter of the pipes. Therefore, the rubber ring does not roll evenly as it enters the socket, and sometimes twists, which is unacceptable. It is also difficult to provide the necessary clearance at the joint between the pipes, since the pipes are pushed in until they touch in the socket, often without any control.
Rice. 19.9. Schemes of a hinged device for mounting reinforced concrete pipes on rubber sealing rings (a), attachments for the installation of pipes with a socket-screw connection (b) and a trench machine for the installation of socket pipes (c): |
Attached equipment for mechanized installation of reinforced concrete pipes, eliminating these shortcomings, was developed by the Tula Polytechnic Institute together with the Tula-Spetsstroy trust and other organizations. Such attachments (Figure 19.9, a) for installation of reinforced concrete pressure pipes on rubberO-rings structurally made in the form of cargo carrier beam with suspension to the hook of the pipe-laying crane. On the beam there are two grippers of the stacked pipe, a gripper of the previously laid pipe and a horizontal feed drive of the stacked pipe. The device has a simple structure and is reliable in operation.
The hydraulic drive is carried out from the hydraulic system of the pipe-laying crane and is designed for pressure up to 10 MPa. At the same time, the force in the docking hydraulic cylinder reaches 95,000 N. Due to the large difference in the mass of pipes of different diameters, four options for such attachments have been developed: for pipes with a diameter of 500; 600 and 700; 800 and 1000; 1200-1400 mm, and changeover from one diameter to another in each variant is carried out using replaceable parts. The mass of attachments for pipes with a diameter of 1200 mm, shown in fig. 19.9, a, is 900 kg.
For the installation of pipes with a diameter of 900 mm, the Yaroslavl Institute of PTIOMES developed attachments for the pipe-laying crane TG-124. Its length is 5600, width and height are 1640 mm. weight 940 kg.
For mechanization installation of reinforced concrete pressure pipes with steelcore type RTNS attachments have been developed, including fixed and movable frames. A hydraulic cylinder is installed in the fixed frame, the rod of which is connected to a cam rod, which acts on all mechanisms of the equipment when the rod moves. An emphasis-grab is rigidly fixed on the movable frame, behind which there is a mechanism with a tong grip.
For installation of reinforced concrete non-pressure pipes with socket-winningcomm connection special attachments have been developed (Fig. 19.9, b) which consists of a frame, roller grips of the laid pipe, grip of the previously laid pipe. Stops are rigidly attached to the frame, mating with the socket and the sleeve part of the laid pipe.
With a pipe-laying crane, the attachments are brought to the pipe to be laid and fixed in roller grips. Then the attachment with the pipe is moved and lowered into the trench, brought to the previously laid pipe, which is fixed with a grip. With the help of a rotation drive and axial feed, the pipe to be laid is screwed into the socket of the previously laid one.
For mechanized caulking of socket pipes with fibrousmaterials a special device is used, which contains a removable caulking unit, consisting of caulking in the form of petals, attached to a three-section roller wheel rigidly fixed on a three-section body. The case rotates on rollers of three-section capture. To carry out caulking, a removable assembly is installed on attachments. Before mounting on the pipe, a strand of hemp or other fibrous material is laid in front of the petals. After lowering into the trench with the help of hydraulic cylinders, the end of the pipe is inserted to the required distance into the socket of the previously laid one. The hydraulic motor is turned on, the petals begin to rotate, at the same time they are progressively introduced into the socket slot and the fibrous material is caulked with a rotational movement.
Trust Spetstyazhtransstroy has developed a device for mechanicszirovanny seal of joints of bell-shaped pipes of big diameter. In this device, the embossing sleeve is equipped with vibration exciters, which ensures an improved quality of pressing the fibrous material into the socket slot of the pipes to be connected.
The design diagram of a special trench machine for the installation of socket pipes is shown in fig. 19.9, in. The machine includes a basic tractor with a pipe pushing transverse beam suspended in front of it and a plow spoon digger and a pit digger placed on opposite end sides, made in the form of a longitudinally inclined boom and a clamshell bucket freely suspended from its head.
The main requirements for the quality of the installation of reinforced concrete pipelines: during the docking process, it is necessary to check the uniformity of the placement of the rubber ring and its rolling. If a backlog is observed in some part of the circumference, it is necessary to “powder” the ring with cement in this place, to exclude further uneven rolling of the ring.
Rings in the gap of socket and socket joints must be compressed by 40-50% of the thickness of their sections. They must not be twisted. In case of violation of the tightness (water tightness) of the joints, they are repaired, for which additional rubber rings or their segments are installed on defective place using a special removable clamp (see Fig. 19.7, h).
Installation of pipelines with coupling butt joints. After centering and checking the correct laying of pipes along the cord, plumb line and sight at the ends of the pipes to be connected, markings are made with risks that determine the initial position of the rubber rings, distances a and b. When installing pipes, the coupling is set to its original position so that its end face on the working side coincides with the on the pipe at risk. The rubber ring is placed near the working ring of the coupling, which is then inserted into the conical slot of the coupling flush with its end using a caulk. At the same time, another rubber ring is put on the second pipe, placing it at a distance b from its end.
Further, with the help of mounting devices, the coupling is advanced towards the pipe to be joined with simultaneous rolling of the first rubber ring. Upon reaching the coupling on the second pipe, risks b from its end, a second rubber ring is inserted into the coupling slot, which ensures the necessary final position of the rubber rings in the joint and its water tightness. The sequence of installation of pipe joints using collarless and single collar couplings is shown in fig. 19.10.
The distance a, b and their fixing the final position of the coupling and rubber rings of the distance c, d, e are given in Table. 19.1.
Non-pressure socket and socket pipes are connected with a gap between the smooth end of the pipe and the socket surface equal to 10 and 15 mm for pipes with a diameter of 700 and more than 700 mm, respectively. The installation of non-pressure pipelines from socket and socket pipes with sealing with rubber rings is carried out by the same methods as pressure ones. The joints are sealed with a hemp strand by caulking the socket to half its depth with two or three turns of tarred or bituminized hemp strands with an asbestos-cement mixture (30% asbestos, 70% cement).
Installation of a pipeline from seam free-flow pipes is associated with the need to seal seam joints. Joints of pipes with a diameter of more than 1000 mm are sealed around the entire perimeter with a hemp strand and rubbed with a 1: 1 cement mortar with a device outside the belt from this solution.
Installation of pipes with a crane using a mounting bracket is carried out in the following sequence: mark the position of the pipe on the base; sling the pipe and lower it into the trench; lay the pipe on the base and verify its position; caulked with a resin strand and sealed with cement mortar; wrap joint reinforcing mesh and monolithic it. The joints of pipes with a diameter of 2000-4000 mm, laid on a concrete and reinforced concrete base, are sealed with shotcrete along the reinforcing mesh.
Table 19.1 Distances when marking the position of the coupling and rubber rings before installation (a, b) and from the ends of the coupling to the rubber rings in the mounted joint (c, d, e) - see fig. 19.10
Coupling |
Distances, mm, from the end to the mark at the end of the pipe |
Distance from rubber ring |
|||
without a collar, but |
with collar, b |
from the end of the coupling from the side |
to its initial position, d |
||
| Types of connections of plastic pipes and methods for their construction. When laying external water pipes from HDPE and LDPE, the main way to connect pipes is to butt-weld them with a heating tool. When installing gravity sewer pipelines, HDPE pipes are connected in the same way. PVC pipes are connected mainly with glue (GIPC-127 brand) in the socket. However, taking into account that thorough cleaning of the surfaces to be glued and careful application of glue are required, deformation of the joints is not allowed, the effect of the glue on the long-term strength of PVC is observed, and in the process of work, harmful substances, recently, socket joints sealed with rubber cuffs of various profiles, as well as O-rings are widely used to connect PVC pipes. In this case, pipes are produced with sockets having annular grooves inside. Flanged connections are mainly used to connect plastic pipes to metal pipes. In places where PVC sewer pipes pass through the walls of wells, couplings with one rubber ring are used as sleeves. Welding of polyethylene pipes, most often contact, is carried out end-to-end (butt), into a socket with cast fittings and into a molding socket (socket welding). When welding pipes, special attention should be paid to outside diameter pipes and their ellipse (ovality). In butt welding, the maximum mismatch of the edges should not exceed 10% of the wall thickness, and the outer 900 mm and 1.5 mm - with a diameter of up to 1200 mm. The ends of the pipes for socket welding must have an external chamfer at an angle of 45 °. Resistance welding of pipes is carried out in the following sequence: installation and centering of pipes in a clamping centering fixture; pipe trimming and end degreasing; heating and melting of welded surfaces; removal of the welding heater; connection of heated weldable ends of pipes under pressure (draft); cooling of the weld under axial load. To obtain strong and high-quality pipe joints, it is necessary to strictly observe the basic welding parameters - temperature and duration of heating, depth of fusion, contact pressure during fusion and upsetting. The main requirements that must be observed when welding pipes are given in Table. 19.2. Bonding PVC (vinyl plastic) pipes carried out mainly in the socket. The process of gluing pipes and fittings made of PVC consists of the following operations: preparing the ends of pipes and sockets for gluing, gluing and curing the joints. The surfaces of pipes and sockets to be glued are degreased with methylene chloride. After that, the glue is applied in a thin layer on the socket and thick on the end of the pipe. Pipes and fittings can be glued at an outside temperature of at least 5°C. Glued joints should not be subjected to any mechanical stress for 5 minutes. Glued lashes and knots before installation must be kept for at least 24 hours after gluing. Connection of PVC pipes on sockets with rubber rings. Pressure socket pipes in the trench are connected in the following order. First, the smooth end and the socket of the pipes to be connected are cleaned of dirt and oils, after which the depth of insertion into the socket is marked on the smooth end with a pencil or chalk. Then a rubber ring is inserted into the groove of the bell, lubricated with liquid soap, and then pushed into the bell to the mark. When connecting non-pressure PVC sewer pipes, couplings are used along with a socket. The technology of their connection using rubber rings is similar to that described above. To assemble socket connections of pressure and sewer pipes, tensioners are used. Table 19.2 Technological mode butt welding of plastic pipes
| |||||
Fig.12. Centering the pipe (a) and inventory pole with a plumb line (b)
1 - pipes; 2 4 - inventory poles; 5 - inventory pole with a plumb line ; 6 - laid pipe
According to the fixed pole installed in the well or the mounted section of the pipeline, the correct laying of the pipe in the plan is checked (Fig. 11). If necessary, it is shifted in the right direction. Finally, with a tensioner (fig.13) the smooth end of the pipe is inserted into the socket of the previously laid one, while monitoring the uniformity of rolling the rubber ring into the socket gap. In this case, it is impossible to allow the end face of the sleeve end to be pushed into the socket until it stops; a gap must be left between them (for which marking is done), and for reinforced concrete pressure pipes with a diameter of up to 1000 mm - 12 + 15 mm, and for pipes of large diameters - 18 + 22 mm. Having connected the pipes, remove the tensioner and tamp the pipe with soil to a height of 1/4 of its diameter with its layer-by-layer compaction with manual rammers.
Fig.13. Stretching device
1 - laying pipe; 2 - laid socket pipe; 3 - pits; 4 - tension screw; 5 - beam; 6 - thrust; 7 - spacer.
When installing pipelines from socketed reinforced concrete pipes, the most time-consuming operation is the introduction of the sleeve end of the pipe with a rubber ring into the previously laid socket. To facilitate it, various devices, devices and mechanisms are used. In particular, two- and three-wire external devices, rack and pinion and hydraulic jacks, internal tensioners, lever and gear winches, bulldozers and excavators are used. (Fig. 14 - 22).
Fig.14. Methods for mounting reinforced concrete pipes and devices used
1 - laid and laid pipes; 2 - half clamp; 3 - rubber ring; 4 - cable; 5,6 - persistent and working beams; 7 - tension screw;
8 - friction ratchet device
For the installation of pipes with a diameter of 500, 700, 900 h, a universal hydraulic device is also used. (fig.22), which is fixed on the pipe, and then lowered into the trench with it. After checking the accuracy of centering the pipe and the correct location of the rubber ring, the pipe is joined to the pipeline under the action of the stroke of the hydraulic cylinder.
Fig.15. Methods for mounting reinforced concrete pipes and devices used
1 - rubber ring; 2 - cable; 3 - tension screw; 4 - swivel clamp; 5 - adjusting screws;
6, 7, 8 - support and movable crosses; 9 - ratchet
When choosing a pipe installation method, the availability of the necessary equipment and mechanisms, as well as the conditions for the construction of the pipeline, are taken into account.
Fig.16. Methods for mounting reinforced concrete pipes and devices used
1 - 2 - rubber ring; 3 - concrete stop; 4 - hydraulic cylinder; 5 - oil pipeline; 6 - pump;
7 - pipe-laying crane
Installation of pipes with a bulldozer (fig.19) can be done if the bulldozer is used when planning (cleaning) the bottom of the trench, i.e. when these two operations are combined. Installation of pipes with a diameter of 1000 .. 1200 mm in trenches with a bottom width of 2.2 m is carried out using a D-159B bulldozer.
Fig.17. Methods for mounting reinforced concrete pipes and devices used
1 - laid and laid pipes; 2 - half clamp; 3 - rubber ring; 4 - cable; 5 - persistent and working beams; 6 - trumpet;
7 - lever winch; 8 - blocks
The method of pipeline installation using an internal tensioning device is recommended for pipes with a diameter of 800 mm or more. Installation of the pipeline using an excavator (see. fig.20) lead when laying pipes in water-saturated soils or in cramped construction conditions, when a trench is torn off as pipes are laid and an excavator located nearby is used during their installation.
Fig.18. Methods for mounting reinforced concrete pipes and devices used
1 - laid and laid pipes; 2 - rubber ring; 3 - cable; 4 - b loki; 5 - cable to the winch; 6 - thrust beam
To ensure the watertightness of butt joints, pipes, sockets and couplings should not be elliptical or their surface quality should not be poor, as well as low-quality rubber rings should not be used.
Fig.19. Methods for mounting reinforced concrete pipes and devices used
1 - laid and laid pipes; 2 - rubber ring; 3 - thrust beam; 4 - bulldozer or tractor
Rings in the gap of socket and socket joints must be crimped by 40 + 50% of the thickness of their section. They must not be twisted. In case of violation of the tightness (water tightness) of the joints, they are repaired, for which additional rubber rings or their segments are installed on the defective place using a special removable clamp (Fig. 20).
Fig.20. Methods for mounting reinforced concrete pipes and devices used
1 - laid and laid pipes; 2 - rubber ring; 3 - trumpet; 4 - thrust beam; 5 - excavator bucket
Installation of pipelines with pipe couplings has a number of differences. After centering and checking the correct laying of the pipes along the cord, plumb line and sight at the ends of the pipes to be connected, marks are made with risks that determine the initial position of the rubber rings - distances a(360, 370mm) and b(70, 80mm).
Fig.21. Methods for mounting reinforced concrete pipes and devices used
1 - rubber ring; 2, 5 - removable and repair collars; 3 - support clip; 4 - pusher; 6 - repair rubber ring; 7 - bolts
When installing pipes, the coupling is set to its original position so that its end face on the working side coincides with the risk applied to the pipe. The rubber ring is placed near the working end of the coupling and then, using a caulk, it is inserted into the conical slot of the coupling flush with its end face. At the same time, another rubber ring is put on the second pipe, placing it at a distance b from her butt. Further, with the help of mounting devices, the coupling is advanced towards the pipe to be joined with simultaneous rolling of the first rubber ring. Upon reaching the coupling on the second pipe, the risks b from its end, a second rubber ring is inserted into the slot of the coupling. In the course of further advancement of the coupling, this ring is also rolled up, which ensures the necessary final position of the rubber rings in the joint and its water tightness.
Fig.22. Methods for mounting reinforced concrete pipes and devices used
1 - laid and laid pipes; 2 - hydraulic cylinder; 3 - traverse; 4 - levers; 5 - clamp pads; 6 - clamp for pipe; 7 - hooks for mounting; 8 - plate.
Installation of non-pressure pipelines is carried out from concrete and reinforced concrete pipes on socket, socket or seam butt joints. The joints of socket pipes are sealed with a hemp strand or other sealants sealed with asbestos cement or rubber rings, and seam pipes with asphalt mastic, bitumen-rubber gaskets and other sealants sealed with cement-sand mortar. Non-pressure socket reinforced concrete and concrete pipes with a diameter of up to 700 mm are connected with a gap between the smooth end of the pipe and the surface of the socket, equal to 8x12 mm, and pipes with a diameter of more than 700 mm - 15x18 m. methods, as pressure (Fig.23 -27).
Fig.23. General layout of mechanisms and performers during laying
pipeline
1 - bell; 2 - base for the pipe; 3 - grab; 4 - laid pipe; 5 - laying pipe; 6 - pipe-laying crane; 7 - pit;
M1- M5 - installers' jobs.
Sealing joints with a hemp strand is carried out by caulking the socket to half its depth with two or three turns of tarred or bituminized hemp strand with caulking with an asbestos-cement mixture (30% asbestos, 70% cement). Installation of pipelines and collectors from seam free-flow pipes is associated with the need to seal seam joints .
Fig.24. Checking the size of the cut (a) and feeding the sand and gravel mixture with the grab
for the base device (b)
Joints of pipes with a diameter of more than 1000 mm are sealed around the entire perimeter with a hemp strand and rubbed with a 1: 1 cement mortar with a device outside the belt from this solution. Installation of pipes with a crane using a mounting bracket is carried out in the following sequence: mark the position of the pipe on the base; sling the pipe and lower it into the trench; lay the pipe on the base and verify its position (the gap between them should not exceed 25 mm); caulk the joint with a tarred strand and seal it with cement mortar; wrap the joint with reinforcing mesh and monolithic it.
Fig.25. Marking the center of gravity of the pipe, slinging the pipe and connecting the smooth end
pipes to the socket of the previously laid
The joints of pipes with a diameter of 2000 + 4000 mm, laid on concrete or reinforced concrete bases, are sealed with shotcrete along the reinforcing mesh.
Installation of asbestos-cement pipelines. Pipes are supplied complete with couplings and rubber o-rings. When they arrive at the on-site warehouse, it is necessary to carefully check their quality and, if defects are found, such pipes and couplings should not be allowed to be laid.
Fig.26. Aligning the vertical position of the pipe with the help of sights
High-quality pipes are laid out along the trench at a distance not closer than 1 m from its edge. Pipes with a diameter of up to 150 mm, as well as couplings, are stacked in stacks up to 1 m high at a distance of up to 100 m from each other. Pipes of large diameters are laid out so that when they are laid in a trench, there is no need for their additional movements.
Fig.27. Horizontal pipe alignment
Piping route layout
Before the beginning earthworks break the pipeline route on the ground. The position of the axis of the route is firmly fixed with signs that provide the ability to quickly and accurately carry out work. The breakdown of the pipeline route is carried out in compliance with the following requirements:
Temporary benchmarks should be installed along the route, connected by leveling moves with permanent benchmarks;
The alignment axes and vertices of the turn angles of the route must be fixed and tied to permanent objects on the ground (buildings, structures, poles of power transmission or communication lines, etc.) or to poles installed on the route;
Crossings of the pipeline route with existing underground structures should be marked on the surface of the earth with special signs;
The locations of the wells should be marked with posts set aside from the route; the number of the well and the distance from it to the axis are written on the columns;
The breakdown of the route must be drawn up by an act with the application of a list of benchmarks, angles of turns and bindings.
Representatives construction organization and the customer, prior to the commencement of excavation work, must jointly inspect the working layout of structures (trenches and pits) performed by the contractor, establish its compliance with the design documentation and draw up an act with an attachment to it of layout schemes and linking to the reference geodetic network.
In the course of earthworks, the construction organization must ensure the safety of all marking and geodetic signs.
To break down the pipeline route along the profile, cast-offs with fixed sights are used, installed at the locations of the wells and at the tops of the turning angles. The length of the running sight is taken as a multiple of 0.5 m for the convenience of sighting; the length of the fixed sight is taken depending on the accepted length of the running sight. On the upper edge of the cast-off, a nail is hammered strictly along the axis, which serves to hang the axis of the pipeline and to determine the center of the well.
Intersection of the pipeline with underground utilities
Underground communications and structures should be marked on the working drawings indicating elevations and distances in plan to the axis of the pipeline. Before starting work, the location of these obstacles must be clarified by the builders and fixed on the track with special signs.
Development of trenches and pits in the immediate vicinity and below the foundation level existing buildings and structures, as well as existing underground utilities, should be carried out only if measures are taken against the settlement of these structures and prior agreement with the organizations operating these buildings and structures.
Measures to ensure the safety of existing buildings in structures should be developed in the project.
The development of soil in trenches and pits when they cross all types of underground utilities is allowed only with the written permission of the organization operating these communications, and in the presence of responsible representatives of the construction organization and the organization operating underground communications.
When crossing trenches with existing underground utilities, mechanized excavation is allowed at a distance of no more than 2 m from the side wall and no more than 1 m above the top of the pipe, cable, etc.
The soil remaining after the mechanized development is finished manually without the use of percussion tools and with the adoption of measures that exclude the possibility of damage to these communications.
The scheme of suspension of communications crossing the trench is shown in Fig.28.
Fig.28. Suspension of communications crossing the trench
a- one or more cables; b- cable ducts in asbestos-cement pipes; in - pipeline;
1 - gas pipeline; 2 - a box of boards or shields; 3 - log or timber; 4 - twist pendants; 5 - cable; 6 - asbestos-cement pipes of cable ducts;
7 - I-beam; 8 - crossbeams from channels; 9 - round steel pendants; 10 - linings; 11 - a pipeline crossing the trench.
Water pipelines at the intersection with sewer pipes are laid 0.4 m higher than the latter, and the water pipes must be steel, but if they are cast iron, they should be laid in steel casings. The length of the casing must be at least 5 m in each direction from the intersection in clay soils and at least 10 m in filtering soils. Intersections are performed at a right angle or close to it. With parallel laying of water and sewer pipelines at the same level, the distance between the walls of the pipes must be at least 1.5 m with conditional pass pipes with a diameter of up to 200 mm inclusive and not less than 3 m with a nominal pipe diameter of more than 200 mm. When laying water pipes below the sewer pipes, the indicated horizontal distances should be increased by the difference in the marks of the depths of the pipelines.
Yard sewer networks may be laid above water lines without casings, with a vertical distance between the pipe walls of at least 0.5 m.
The clear distances between the walls of several sewer pipelines laid in one trench at the same elevations should ensure the possibility of laying pipelines and sealing joints and be at least 0.4 m. When parallel laying water lines, the distance between them, m, is recommended to be taken :
With pipes with a diameter of up to 300 mm - 0.7;
With pipes with a diameter of 400 to 1000 mm - 1;
With pipes with a diameter of more than 1000 mm - 1.5.
Foundation preparation
Water and sewer pipes, if the project does not provide for an artificial foundation, should be laid on natural soil of an undisturbed structure, ensuring the transverse and longitudinal profile of the base specified by the project, while the pipes along the entire length should fit snugly against the base.
Laying pipes on frozen ground is not allowed, except in cases where dry sandy, sandy loamy and gravel soils, as well as rocks, lie at the base. Laying pipes on bulk soils can be carried out only after compacting them to the density adopted in the project with testing of selected samples.
When laying pipelines in rocky soils, the base of the trenches should be leveled with a layer of compacted soft soil with a height of at least 0.1 m above the protruding irregularities of the base. To level the bases of steel pipelines, soil is used that does not contain inclusions of coarse gravel and stones. In peat and quicksand soils, pipelines of any diameter are placed on a pile foundation with a concrete pad.
During the construction of pipelines in soils of type I, according to subsidence, the base is compacted with heavy rammers, in soils of type II, preliminary soaking of the base of the trenches is used.
Pipes can be laid in a trench on a flat base; on a solid concrete or reinforced concrete foundation; on a base profiled for a fillet with a wrap angle of 90 and 120 °.
The flat base on which the pipes are laid must be horizontal in the transverse direction and have a design slope in the longitudinal direction.
When resting on a concrete foundation, the pipes are laid in a tray with a coverage angle of 120 ° in soils with a standard resistance of at least 0.1 MPa. Pipes, especially flexible steel and polymer pipes, laid on a soil profiled base, open in the shape of a pipe with an angle of support of up to 120-150 °, can take much greater loads. When laying the pipeline on a profiled soil base (fillet), aligned along the length of the trench, thin-walled steel pipes, which gives a significant savings in metal.
Selection of crane equipment
The choice of a crane for lowering pipes into a trench is determined by the mass of the pipes and the required reach of the crane boom (the distance from the axis of the trench to the axis of rotation of the crane boom). The required reach of the crane boom is found by the formula
,
where E - the width of the trench on top at the highest allowable steepness of the slopes; b - the distance from the edge of the trench to the wheels or caterpillars of the crane (taken at least 1.5 m with a trench depth of 1.5 m and 2 m with 1.5-3 m); in- the distance from the wheels or caterpillars of the crane to the axis of rotation of its boom.
When laying main pipelines in whips or long sections in trenches with vertical slopes, the distance from the edge of the trench to the wheels or caterpillars of the crane should be 
(where H - trench depth; 0.2 - distance from the edge of the pipe to the collapse prism; -
outer diameter of the pipe; 0.3 - distance from the edge of the pipe to the crane caterpillars).
Pipe laying
Before laying the pipes, it is necessary to check the compliance with the design of the bottom marks, the width of the trench, the laying of the slopes, the preparation of the base and the reliability of the fastening of the walls of the open trench; inspect pipes, fittings, fittings and other materials brought in for laying and, if necessary, clean them from contamination.
Pipes along the pipeline route are placed in various ways (Fig. 29), depending on the crane equipment adopted for laying pipes in the trench.
Fig.29. Laying of socket pipes along the pipeline route
a - laying by crane from one parking lot of two pipes; b - laying by crane from one parking lot of three pipes; in - when laying pipes, the crane moves along the trench.
The sequence of work on laying pipelines should occur in the following sequence:
The bottoms of wells and chambers are arranged before the pipes are lowered;
The walls of the wells are erected after laying pipes, sealing butt joints, installing fittings and valves;
trays in sewer wells arrange after laying the pipes and erecting the walls of the wells to the pipe shelyga;
Fittings and valves located in the well are installed simultaneously with pipe laying;
Hydrants, plungers and safety valves installed after testing pipelines.
With a centered butt joint, each laid pipe must rest firmly on the base soil.
All socket pipes are laid with a socket forward, on straight sections of the route in a straight line in a horizontal and vertical plane.
The straightness of sections of non-pressure pipelines between two adjacent wells should be controlled by looking at the light with a mirror. When viewing a pipeline of circular cross section, the circle visible in the mirror should have correct form. The permissible deviation from the shape of a circle horizontally should be no more than 1/4 of the diameter of the pipeline, but not more than 50 mm in each direction. Vertical deviation from the circle shape is not allowed.
Laying a pipeline along a gentle curve without the use of fittings is allowed only when using butt joints on rubber seals with a turn in each joint of no more than 2 ° for pipes with a diameter of up to 500 mm and no more than 1 ° for pipes with a diameter of more than 500 mm.
Dead-end ends of pressure pipelines should be fixed with stops. In places where the direction of the pipeline changes in the horizontal plane, the stops are arranged on the outside of the angle of rotation. The design of the stops is provided by the project.
When laying cast-iron, concrete, reinforced concrete and ceramic pipes with sealing of butt joints with sealants 51-UT-37A and KB-1 (GS-1), transfer to the joints of the external load from the soil or internal hydraulic pressure allowed after they have been held for a certain period of time. The quality of work on sealing butt joints with sealants should be controlled by a construction laboratory. The quality of sealant preparation, the quality of cleaning and mechanical processing of sealed surfaces, as well as the duration of vulcanization (hardening) of the sealant in the joint are subject to control.
Careful tamping of the soil when backfilling the space between the pipe and the walls of the trenches increases the resistance of the pipe to crushing by 20%.
Immediately after laying the pipeline in the trench, the pits and sinuses are filled with soft soil and knocked out (simultaneously on both sides), and then the trench is filled up 0.5 m above the top of the pipe, leveling the soil in layers and compacting with manual and mounted electric rammers.
Foundation device for pipelines
The type of foundation is selected depending on the hydrogeological conditions, the size and material of the pipes to be laid, the design of the butt joints, the laying depth, traffic loads and local conditions. In order to avoid unacceptable settlements during pipe laying, the base must have sufficient strength to balance all active forces, i.e. external loads acting on the pipe.
The following types of bases are provided for pressure reinforced concrete pipelines:
Flat soil base with a sand cushion and without a sand cushion (Fig. 30, a);
A profiled soil base with a coverage angle of 90 ° with a sand cushion and without a sand cushion (Fig. 30, b and c, respectively).
Concrete foundation with a spanning angle of 120° with concrete preparation (Fig. 30, d).
Fig.30. Foundations for reinforced concrete pressure pipelines
1 - backfilling with local soil with a normal or increased degree of compaction; 2 - sand cushion; 3 - concrete foundation; 4 - concrete preparation.
Backfilling is provided by local soil with a normal increased degree of compaction.
The following types of bases are provided for non-pressure pipelines:
For pipes 
mm in sandy and clay soils with a standard resistance of 0.15 MPa - a flat sandy base and a clay base with sand preparation in a profiled groove (Fig. 31);
Despite the fact that, along with reinforced concrete, other materials are used today for the production of pipes, it is still in demand. In case of violation of the waterproofing of such pipelines, the materials of the Penetron system come to the rescue.
Relevance of the problem
With the transformation of small towns into megacities at the end of the 19th century, to ensure uninterrupted water supply, there was a need for large diameter pipes. With the development of production and the improvement of the technological process, pipes began to be produced, the diameter of which reaches 1200, 1800 mm and more.
Successful and long service experience in utilities has proven that reinforced concrete continues to be one of the most preferred materials for the production of a wide segment of pipes.
Yes, in Western Europe in the sewer, plastic is used mainly for pipes with a diameter of up to 250 mm when laying house networks. For main pipelines, with a pipe diameter of 300 to 600 mm, ceramics and reinforced concrete are used, and the larger the pipe diameter, the higher the proportion of reinforced concrete. The reason is obvious - the loads experienced by the main pipelines, plastic can withstand worse than reinforced concrete.
In Russia, reinforced concrete pipes have three main areas of application: pressure water supply and water supply systems and industrial, household, storm free-flow sewerage, as well as pipeline systems of engineering communications.
If water is aggressive to concrete, then, according to GOST 6482-88 "Reinforced concrete non-pressure pipes", the project should provide for protection measures. But in practice this often does not happen. If in non-aggressive environments the service life of concrete is 50 years or more, then in slightly aggressive environments it decreases to 20 - 30 years. In medium-aggressive environments, the service life is even lower, and therefore secondary corrosion protection methods should be used.
A sharp decrease in the reliability of pipelines began to be evidenced by the frequent accidents of water supply and sewer systems. According to official data, approximately 60% of pipelines are already subject to corrosion, and 10% are in a pre-emergency state and require repair.
Apart from corrosion processes occurring during the operation of pipelines, the cause of a violation of water tightness may be poor-quality sealing of the butt joint between pipes.
In the old fashioned way, it is customary to use hemp as sealing materials, followed by sealing with a cement-sand mortar. At the same time, being a complex, and most importantly, unreliable technological operation, this method of caulking requires High Quality production of works. Although the sealing of butt joints using rubber sealing rings, which is increasingly used, is simpler and more reliable.
During the filling of the embankment or during the settlement of the soil, concrete pipes experience significant deformations, which often leads to a violation of the tightness of the butt joint between the pipes and subsequent leaks during operation. Only after several years of operation, when the processes of upsetting and longitudinal deformations of pipes are stabilized, it is recommended to fill the butt joints with cement mortar.
Below is Alternative option device for waterproofing a butt joint between reinforced concrete pipes of large diameter, used both in the performance of repair work and in the new construction of main pipelines. In this embodiment, a bentonite self-expanding gasket "Penebar" is used.
Work performance technology
When repairing reinforced concrete non-pressure socket pipes of large diameter (diameter over 2400 mm), one often encounters a violation of the tightness of the socket connection - the rubber seal is displaced, and as a result, leaks are observed at the point of contact of the installed pipes.
Stage I: surface preparation
1. On the outer side, along the entire length of the joint between reinforced concrete pipes, make U-shaped grooves with a section of 70x25 mm using an angle grinder, puncher or other tool.
2. Clean the resulting streak and the concrete surface with a metal bristle brush from dirt (if any), dust and concrete chips. Joint edges must be structurally sound and clean.
Stage II: sealing joints
1. Moisten the prepared strains.
2. Remove the release paper from the surface of the Penebar hydro-seal.
3. Lay the hydraulic gasket in the cavity of the groove.
4. Prepare the solution waterproofing material penetrating action "Penetron".
5. Prime the streak with a solution of the Penetron material in one layer with a brush made of synthetic fiber.
6. Prepare a solution of suture material "Penecrete". Tightly fill the remaining cavity of the chisel with it (material consumption 1.5 kg / mp with a chisel cross section of 25x25 mm).
7. After hardening of the solution of the material "Penecrete" thoroughly moisten the surface of the concrete.
8. Prepare a solution of Penetron penetrating waterproofing material and apply it in two layers with a synthetic fiber brush on the concrete surface.
9. Apply the first layer of "Penetron" material on damp concrete (material consumption 600 g/m2). Apply the second layer on a fresh but already set first layer (material consumption 400 g/m2).
Stage III: surface care
1. Treated surfaces should be protected from mechanical influences and negative temperatures within 3 days.
2. At the same time, it is necessary to ensure that the surfaces treated with the materials of the Penetron system remain wet for 3 days, cracking and peeling of the coating should not be observed.
3. The following methods are commonly used to moisten the treated surfaces: water spray, covering the concrete surface with polyethylene film.
Concrete concrete products are complex engineering structures that have found a wide scope of application in residential, agricultural and industrial construction. Today they are created on the basis of high-performance technologies are in no way inferior to their plastic and cast-iron counterparts. Moreover, such products attract the opportunity to save money in residential, agricultural and industrial construction projects.
High-quality ones can last over 70 years. At the same time, such products are not subject to bacterial effects, are not afraid of heat, drought, moisture and frost. On the this moment they are widely applied in the following fields:
- In private construction of structures;
- AT industrial production protective elements, supports, etc.;
- In the arrangement of sites;
- In the creation of ditches, storm systems, collectors;
- In the manufacture of sewer outlets;
- To create stocks.
The choice of such suitable products depends on the purpose, size and complexity of the installation.
Pipes concrete sewer bell-shaped
Modern ones have a throughput diameter of 100 to 2400 millimeters. In this case, the value of this parameter directly depends on the dimensions, purpose and their type. Another important characteristic is their resistance to aggressive environments. To improve this property, modern manufacturers of building materials add to concrete mix various additives. Such components improve the resistance to acids and alkalis. Actually for this reason, they are used for the manufacture of not only municipal, but also industrial drains.
Given the wide scope of these products, it becomes clear that they must have high strength in order to withstand linear loads. They withstand internal pressure from 0.1 MPa to 2 MPa.
When choosing, it should be borne in mind that today manufacturers offer several options for joints. In particular, they can be installed in a socket or in folds. At the same time, today all of them can be conditionally divided according to the scope of application into pressure and non-pressure products. The first option is made either from pure concrete, or with impurities of polymers and steel inserts. Bushings made of plastic or steel are designed to provide greater resistance to aggressive environments.
Varieties and sizes are determined by GOST 22000-86.
The main types of concrete pipes
- TBPF;
- TBPS.
Types of concrete pipes
- Socket sewer with butt joints (TB).
Such products are distinguished by the fact that one of their ends is somewhat expanded. They are classified as non-violent. They are designed to work with non-aggressive liquid, the temperature of which should not exceed 400 degrees. These products are sealed with rings, sealant or impact-resistant materials. As for the installation method, the installation is carried out end-to-end. In turn, TB according to the state standard are divided into:
- T-cylindrical;
- TB with rubber rings and a persistent side;
- TS cylindrical with stepped surface;
- TFP are cylindrical.
- TBS socket sewer:
This variety belongs to the non-pressure type. Products included in this group, as a rule, have an internal wall diameter of 400 millimeters. Moreover, their lengths can reach 2500 millimeters. Most often, TBS is used for the construction of household sewer networks. These varieties are produced by vibrohydropressing. Actually, the use of this technology is due to high technical characteristics.
- TBP seamed cylindrical pipes:
The diameter of this type of socket can vary from 400 to 2400 millimeters. At the same time, when choosing such products, it is important to take into account other parameters. In particular, if you are interested in a diameter of 1600 millimeters, then according to bearing capacity TBP can have 2 grades depending on the cross-sectional area. This parameter is determined by the height of the pipeline falling asleep. Pipes with a diameter of more than 1600 millimeters are used with a backfill height of not more than 4 meters. When working with TBP, it is very important to install the base along the entire height with soil, supplemented with a layered compactor.
- TBPV seam pipes with sole:
Concrete rebate type, equipped with a sole, are non-pressure products that are used to conduct pipelines underground. Socket solutions include the use of special couplings that are designed to simplify the installation of materials. The advantages of TBPV include the possibility of installation on an uneven surface.
- TBPS pipes, the joints of which are sealed with rubber inserts:
This type is produced in accordance with GOST 20054. We are talking about cylindrical socket products with a sole and a butt surface. At their ends there are special bushings that simplify the installation of products and ensure the durability of the structure. For better stability, manufacturers supplement TBPS with special rubber rings.
- 6. Concrete pipe into the ditch for arrival:
The diameter of these can vary from 400 to 2400 millimeters. The surface of the sleeve end can be equipped with rubber rings. This provides products with greater density and wear resistance.
Concrete sewer pipes, in turn, are divided into:
- non-pressure concrete pipes
- concrete road pipes
- rectangular concrete pipes
Installation of concrete pipes - video
It should be noted right away that the installation of sewer pipes is a complex process that requires the use of special equipment, certain knowledge and skills. For this reason, it is better to turn to professionals who have experience in this work than to try to do the installation yourself.
When laying sewer networks, it should be borne in mind that the coupling concrete structures are mounted in their original position so that the end coincides with the mark. Moreover, if the products are equipped with rings with an elastic band, then they should be as close as possible to the coupling rings. The latter, in turn, must be in a conical coupling gap and go flush. To get them to the specified place, you should use a caulk.
After completing the above steps, an additional rubber ring must be added to the end of the second pipe. It is desirable that it be located near the end. After that, using a special tool, the coupling is advanced to the pipe to be joined strictly in the direction. In parallel with this action, it is necessary to roll the ring on the first pipe. For this reason, the installation of sewerage must be carried out by a group of specialists. It is physically impossible to cope with this task on your own.
After the coupling reaches the mark on the other sewer pipe, a second rubber ring must be placed in the slot. This will ensure proper water tightness, which is necessary for the correct positioning of the rings at the joints. If this quality cannot be achieved, the pipes will not last long.
Dimensions of concrete pipes
T-pipe dimensions
| D, mm | Pipe type | Pipe dimensions, mm | Pipe weight, t | |||||||||
| d i | d e | d1 | d2 | t | l | l 1 | l 2 | l 3 | l 4 | |||
| 400 | Т40.50 | 400 | 500 | 530 | 650 | 50 | 5000 | 5100 | 100 | 150 | 75 | 0,95 |
| 500 | T50.50 | 500 | 620 | 650 | 790 | 60 | 85 | 1,4 | ||||
| 600 | T60.50 | 600 | 720 | 750 | 890 | 1,7 | ||||||
| 800 | T80.50 | 800 | 960 | 990 | 1170 | 80 | 5110 | 110 | 200 | 105 | 3,0 | |
| 1000 | T100.50 | 1000 | 1200 | 1230 | 1450 | 100 | 125 | 4,8 | ||||
| 1200 | Т120.50 | 1200 | 1420 | 1450 | 1690 | 110 | 135 | 6,0 | ||||
| 1400 | T140.50 | 1400 | 1620 | 1650 | 1890 | 7,0 | ||||||
| 1600 | Т160.50 | 1600 | 1840 | 1870 | 2130 | 120 | 145 | 8,7 | ||||
Dimensions of pipes type TB
| D, mm | Pipe size | Pipe dimensions, mm | Pipe weight, t | ||||||||||||||
| d i | d e | d1 | d2 | t | t1 | a | l | l 1 | l 2 | l 3 | l 4 | h | h1 | h2 | |||
| 400 | TB40.50 | 400 | 500 | 531 | 684 | 50 | 76,5 | 44 | 5000 | 5145 | 145 | 365 | 102 | 92 | 11 | 6 | 0,95 |
| 500 | TB50.50 | 500 | 620 | 651 | 834 | 60 | 91,5 | 59 | 5160 | 160 | 425 | 105 | 107 | 1,5 | |||
| 600 | TB60.50 | 600 | 720 | 751 | 934 | 1,7 | |||||||||||
| 800 | TB80.50 | 800 | 960 | 991 | 1210 | 80 | 109,5 | 482 | 125 | 3,0 | |||||||
| 1000 | TB100.50 | 1000 | 1200 | 1231 | 1498 | 100 | 133,5 | 590 | 149 | 7 | 4,8 | ||||||
| 1200 | TB120.50 | 1200 | 1420 | 1451 | 1740 | 110 | 144,5 | 69 | 5170 | 170 | 634 | 115 | 160 | 6,3 | |||
| 1400 | TB140.50 | 1400 | 1620 | 1651 | 1946 | 147,5 | 74 | 5175 | 175 | 163 | 13 | 7,3 | |||||
| 1600 | TB160.50 | 1600 | 1840 | 1871 | 2196 | 120 | 159 | 84 | 5185 | 185 | 654 | 125 | 178 | 9,0 | |||
Attention! Pipes with a diameter exceeding 900 millimeters must be equipped with a double welded frame. Such socket sewer pipes made of concrete are produced in accordance with GOST 6482-88. Regarding the installation of large pipes, it is important that the gap between the joints is 10-15 millimeters. In addition, the joints must be connected with a quality foam strand.
Construction of concrete pipes
How a reinforced concrete pipe is arranged - design
If a few years ago they were made from massive walls equipped with bends, then modern analogues are much more convenient and practical. The walls of modern sewer pipes can have either a separate or a common foundation. Everything depends directly on the geological conditions in which the operation of the product is envisaged.
For weak soils, they are produced with a common foundation, which can significantly reduce the pressure. In some cases, for greater efficiency, manufacturers make a reverse vault for a common foundation. In this case, this element performs two important tasks: Allows water to flow out and acts as a drip tray. Such products are made from rubble stone.
If they need to be installed on roads that belong to low technical categories, it is better to use products that have a round base of links. At the same time, it is good if they are additionally equipped with a flat sole. In such pipes, the links can have a hole with a diameter of 1 to 1.25 meters. The thickness of their walls in this case can vary from 14 to 16 centimeters.
In the device of the plantar part there is a welded mesh made of reinforcement with a diameter of up to 10 millimeters. The metal used for the manufacture of this structural element must be of class A-II. However, today there are two types of links:
The only drawback of these classes is not efficiency. For laying sewers from such materials, a lot of concrete is needed. As a rule, these pipes are installed under embankments. Their height can reach up to 7 meters.
It should be borne in mind that the links of round sewer pipes are very difficult to evenly place on the base of the foundation or foundation. In order to avoid mistakes during the installation process, manufacturers offer a standard project of links. In addition, you can use additional meshes that allow you to strengthen the heel of the reinforcement.
GOST
|
Inner diameter |
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|
Usable length |
Minimum wall thickness |
Depth of socket |
Rebate depth |
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T, TB, TS, TF |
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T, TP, TB, TS, TBP, TSP, TFP |
2500-3000 |
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TP, TBP, TSP, TFP |
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Prices and cost of concrete pipes
The cost of reinforced concrete products depends on the manufacturer and their purpose. As a rule, they cost a little more than their plastic counterparts, but they attract with the best operational characteristics. For example, in a ditch, it can cost, depending on the manufacturer and diameter (300-2000 millimeters), from 3,000 to 50,000 rubles per unit.
Thus, we examined the features, varieties and features of the installation of sewer BTs. Summing up, it can be noted that they have a number of advantages compared to analogues, which is due not only to their durability, but also to a relatively affordable price.
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