Concrete and reinforced concrete pipes are laid on a natural or artificial base. The joints of pressure pipes (bell or socket) are sealed with rubber sealing rings, and non-pressure (bell or seam) - with a 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.
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 is carried out in such
sequences: delivery of pipes and laying them 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, a concrete stop is installed at the beginning of the route, which ensures a stable position for the first two or three pipes when they are connected into a socket.
The most time-consuming part of the work is the connection of the sleeve end of the pipe with the socket of the already laid one. For accuracy, it is necessary to take measurements, and to give the necessary strength, they use special devices and equipment.
Installation of concrete and iron concrete pipes at present, they conduct mainly two technological schemes. First, apply attachments 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 the 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.
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, marks are made with risks that determine the initial position of the rubber rings, distances a and b.
When installing pipes, the coupling is installed in starting position so that its end face on the working side coincides with the risk applied on the pipe. The rubber ring is placed near the working ring of the coupling, which is then inserted into the conical slot of the coupling using a caulk.
flush with its end. 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.
Non-pressure socket and socket pipes are connected with a gap between the smooth end of the pipe and the surface of the socket 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
tarred or bituminized hemp strand caulked 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 overwritten cement mortar composition 1:1 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
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 a reinforcing mesh (see Fig. 24.34).
Lecture 29
LECTURE PLAN
ADDITIONAL LITERATURE
1. Popov A.I., Zionsky A.L., Khripunov V.A. Production of reinforced concrete pressure vibrohydropressed pipes. - M .: Stroyizdat 1979.
2. Cards labor processes. Installation of external water supply and sewerage networks. Sh-10-9.1 and KKT-Yu.O-Z.M., Stroyizdat, 1563, 1986.
3. VNII Vodgeo. Installation guide for reinforced concrete, cast iron,
asbestos-cement pipelines. - M.: Stroyizdat, 1979.
4. Pereshivkin AD., Alexandrov A.A., Gotovtsev V.I. Installation of pressure
pipelines with butt joints on rubber seals. - M.: Stroyizdat, 1986.
TECHNICAL MEANS
- filmstrip "The device of external pipelines from non-metallic
pipes".
2. Poster "Concrete and reinforced concrete pipes".
3. Poster "Methods of installation of socket reinforced concrete pipes and devices used."
4. Poster "Arrangement of pipelines from reinforced concrete pipes".
Reinforced concrete and concrete pipes, for laying pressure conduits, vibrohydraulic presses are used. and centrifuge. reinforced concrete socket pipes of 3 classes (1st for pressure 1.8 MPa, 2nd - 1.3 MPa and 3rd 0.6-0.7 MPa) 5 m long and 500,600,700,800,1000 in diameter, 1200, 1400 to 1600 mm with the mass of vibrohydropresses. pipes from 1.32 to 8.2 tons and centrifuges. from 1.43 to 9.63 tons.
For non-pressure pipelines, concrete non-pressure pipes with a diameter of 100-1000 mm l \u003d 1-2 m are used, as well as reinforced concrete non-pressure pipes with a diameter of 400,500,600,800,100C,1200,1400,1600,2000,2400 mm and folded pipes with a diameter of 400,2400,3000,3400,4000 mm . Non-pressure pipes perform two varieties - norms. strength (M), way. to a depth of 3-5 m (above the top) and reinforced (y), laid to a depth of 5-6 m.
Concrete and reinforced concrete pipes are laid on a natural and artificial base. The joints of pressure pipes are socket and socket joints with waterproof sealing with their rubber seals, and non-pressure pipes are socket and seam with sealing of their resin or bituminized strand, asbestos-cement or cement lock, as well as asphalt mastic.
Before laying pipes in a trench, they, as well as couplings, during their acceptance must be subjected to an external inspection to identify possible defects, as well as to check the dimensions of the pipes. Pipe Quality Inspection is to establish compliance with their main characteristics of GOST and specifications(THAT).
Laying pipes along the edge of the trench. Concrete and reinforced concrete bell-shaped pipes, as well as other pipes, are laid out along the pipeline route in various ways, the choice of which is determined by the type and lifting capacity of the cranes received, designed to lower the pipes into the trench.
Installation of pressure pipelines. Pressure pipelines are mounted from socketed and smooth reinforced concrete pressure pipes manufactured at factories by vibrohydraulic pressing or centrifugation and corresponding in quality to the requirements (for details, see)
Installation of pipelines from socket reinforced concrete pipes lead in the following sequence: delivery of pipes and laying them along the trench, feeding them to the place of laying; preparation of the sleeve end of the pipe and installation of a rubber sealing ring on it; insertion of the pipe to be laid with the spigot end with a rubber ring into the previously laid socket; giving the newly laid pipe the design position; final sealing of the joint; preliminary testing of the finished section of the unfilled pipeline (and for pipes of large diameters, only butt joints) for tightness; backfilling this area with tamping the earth in the sinuses; final test of the backfilled pipeline. Installation of pipes is carried out using cranes, pneumatic or crawler cranes. Pipes from the trench berm to the place of laying are served with a socket forward in the course of installation. Before laying the first pipe, a concrete stop is installed at the beginning of the route, which ensures a stable position for the first two or three pipes when they are connected.
The recommended arrangement of mechanisms, pipe-laying workers and pipe layout during pipeline installation is shown in Fig. 1, a. When laying, first, according to the template, mark on the smooth end of the pipe to be laid the depth of embedding it into the socket of the laid pipe. After installing the assembly crane in the middle of the pipe being laid, a semi-automatic tong grip is lowered onto it and it is slinged. In the absence of such a grip, the pipes are slinged using slings or a traverse with towels. Then the pipe is fed into the trench by a crane. At a height of 0.5 m from its bottom, the lowering of the pipe is suspended and a rubber ring is put on its smooth end, after which it is led into the socket of the previously laid pipe and smoothly lowered onto the prepared base. Wherein Special attention give centering of the sleeve end of the introduced coarse 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 (Fig. 1, c), a running sight is supported on its tray and then it is monitored that the top of this sight is on a common line of sight with two fixed sights of the cast-off. After aligning the pipe vertically, the grip is removed from it, the crane is released for the installation of the next pipe, and the position of the pipe in the planet is started to be adjusted. For this purpose, inventory stakes are installed along a plumb line: one at the end of the pipe being laid, and the other at the previously laid pipe. According to the fixed pole installed in the well or on the mounted section of the pipeline, the correct laying of the pipe in the plan is checked. If necessary, it is mixed in the right direction. After that, using a tensioner, the smooth end of the pipe to be laid is inserted all the way into the socket of the previously laid pipe, while monitoring the uniformity of rolling the rubber ring into the socket gap. Having docked the pipes, remove the tensioner and knock the pipe with soil to a height of 1/4 of its diameter with layer-by-layer compaction with its manual rammers.
When installing conduits from socketed reinforced concrete pipes, the most time-consuming process is the introduction of the bushing end of the rough with a rubber ring into the previously laid socket. To facilitate this operation, various devices, devices and mechanisms are used that determine the appropriate methods for installing pipelines. In particular, two- and three-cable external tensioners are used (Fig. 2, a, b), rack or hydraulic jacks(Fig. 2, c), internal tensioners, lever and gear winches (Fig. 2, d, e), bulldozers and excavators (Fig. 2, f, g).
For the installation of pipes with a diameter of 500, 700, 900 mm, a universal hydraulic device of the Orgtekhvodsgroy Glavvolgovodstroy trust (Fig. 2, h) is also used, which is first fixed on the pipe, and then lowered into the trench together with the pipe. After checking the accuracy of centering the pipe and the correct location of the rubber ring, the pipe is joined to the pipeline by the action of the stroke of the hydraulic cylinder.
When choosing a method for installing reinforced concrete pipes, the presence of necessary equipment and mechanisms, as well as local conditions of construction. The installation of pipelines using a bulldozer (Fig. 2, e) can only be carried out if the bulldozer is also used for laying the foundation of the trench, i.e. when it is possible to combine two work operations. Trust Tsentrospetsstroy manufactured a small-sized bulldozer based on the T-54V tractor with a blade width of 1.25 m, which is used for the installation of pipelines with a diameter of 500 mm or more while simultaneously laying out the foundation of trenches. The method of pipeline installation using an internal tension device can only be recommended for pipes with a diameter of 800 mm or more. Installation of the pipeline using an excavator (Fig. 2,g) is carried out when laying pipes in water-saturated soils or in cramped construction conditions, when it is not possible to open trenches in advance, and an excavator located nearby can be used for pipe installation. When connecting pipes, it is impossible to move the smooth end into the socket completely, i.e. to the full stop, and a gap should be left between the end face of the smooth end and the stop surface of the socket for pipes with a diameter of up to 1000 mm - 15 mm, and for pipes with a diameter of more than 1000 mm - 15 mm. or Bad quality pipe surfaces and use low-quality rubber rings. Rings in the gap of socket and socket joints must be compressed by 40-50% of the thickness of their section. In case of violation of the tightness (water tightness) of the joints, additional rubber rings or their individual segments are installed directly on defective place using a special removable clamp (Fig. 2, i). In case of damage or significant defects in reinforced concrete pipes, they are removed and replaced with inserts made of steel pipes using steel transition pipes
Installation of pipelines with coupling butt joints of pipes has a number of differences. So, after centering and checking the correct laying of the rough on the cord, plumb line and sight at the ends of the connected pipes, marks are made with risks that determine the initial position of the rubber rings - distances a (360.370) and b (70.80 mm). 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, a rubber ring is also put on the second pipe and placed at a distance b from its end. Further, with the help of mounting devices, the coupling is advanced towards the pipe to be joined and at the same time the first rubber ring is rolled up. Upon reaching the coupling on the second pipe, the risks at a distance b from its end face, a second rubber ring is inserted into the coupling slot. In the course of further advancement of the coupling, this ring is also rolled up, due to which the required final position of the rubber rings at the junction is achieved.
Installation of non-pressure pipelines. It is carried out from concrete and reinforced concrete pipes on socket, socket or seam butt joints. 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 with seals. cement-sand mortar. Non-pressure socket and socket pipes are connected with a gap between the smooth end of the pipe and the stop surface of the socket, equal to 10 and 15 mm for pipes with a diameter of 700 and more than 700 mm, respectively.
The installation of pipelines from socket and socket pipes with sealing with rubber rings is carried out by the same methods as for pressure conduits. The joints are sealed with a hemp strand by caulking the bell to half its depth with two or three turns of tarred or bituminized hemp strand with a caulked asbestos-cement mixture (30% asbestos, 70% cement).
Installation of pipelines from seam free-flow pipes is associated with the need to seal the seam joints. At the same time, the 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. Joints of Maltz pipes with a diameter of 2000-4000 mm, laid on concrete or reinforced concrete bases, are sealed with shotcrete along the reinforcing mesh. In this case, the pipes are laid in the trench with a crane using a mounting bracket. Installation of pipes is carried out in the following sequence: mark the position of the rough on the base; sling the pipe and lower it into the trench; lay the pipe on the base and verify its position; caulk the joint with a resin strand and seal it with cement mortar; wrap the joint with reinforcing mesh and monolithic it.
fig.1
a - general scheme organization of work
b - pipe laying and alignment
1 - pipes
3 - trenches
4 - pits for sealing joints
5 - pincer grip
6 - running sight
7 - sewn-on sights
General provisions. Small culverts: bridges up to 25 m long and pipes are among the massive objects of railway construction. The number of small culverts on the 1st km of the route depends on the shape of the terrain. Yes, for railways Ural and Eastern Siberia the number of small bridges (numerator) and pipes (denominator) is: in flat terrain - 0.1/0.24, in hilly terrain - 0.14/0.53, in mountainous terrain - 0.21/0.9 pieces / km , and their share from total number culverts N: 26/58, 18/74.6 and 15.5/79.5%, respectively.
Thus, in total, small bridges and pipes make up from 84 to 95% N. Small bridges and pipes are built according to standard designs from prefabricated structures. Most common in last years received round prefabricated reinforced concrete pipes with holes of 1.0, 1.5 and 2.0 m in one-two- and three-point design; rectangular prefabricated reinforced concrete pipes with holes 1.0; 1.5; 2.0; 3.0, 4.0 m in one- and two-point execution; rectangular concrete pipes with holes 2, 3, 4, 5 and 6 m; corrugated metal pipes with holes 1.0; 1.5; 2.0 and 3.0 m.
The pipe consists of an inlet head, a pipe body and an outlet head (Fig. 9.4). Both the heads and the body of the pipe are assembled from separate blocks. Foundations are of three types. On the solid foundations, for example, rock foundations, type I foundations are used, consisting only of curved blocks (for round pipes) or slabs (for rectangular pipes). On relatively weak foundations, foundations are made of monolithic concrete - type III. In other conditions, type II foundations are used, which differ from type I foundations by an additional lower row of rectangular blocks. The foundation under the heads is arranged to a great depth. The pipe consists of links 1 m long and head blocks. The mass of mounting elements of typical reinforced concrete pipes: foundation blocks 0.75 ... 4 t, round links 0.9 ... 4.2 t, rectangular 3.5 ... 10.3 t, parts of heads 2.4 ... 6.9 t. foundation blocks they are laid by a crane on a layer of crushed stone (sand and gravel) preparation with a thickness of 0.10 ... 0.20 m.
Rice. 9.4. Precast concrete pipes:
a - round; b - rectangular; / - portal wall of the head; 2 - links; 3 - conical link; 4 - sloping wing of the head; 5 - base plates of the head; 6 - crushed stone preparation; 7 - foundation blocks; 8 - curved blocks; 9 - foundation slabs; 10 - tray
Metal non-foundation pipes are mounted from factory-made corrugated elements, produced in the usual and northern versions. Elements made of steel with a thickness of 1.5 ... 2.5 mm have corrugations (ridges) 32.5 mm high with a step of 130.0 mm. With the help of bolts, the elements are combined into links. To protect against corrosion, pipe elements are coated with a layer of zinc and special bituminous mastics or polymer enamels. Pipes are laid on a sand or sand-gravel pad with a thickness of at least 0.40 m with a particle size of not larger than 50 mm. Corrugated pipes are arranged, as a rule, without heads. At the end sections of the pipe, impervious underflow screens are arranged - waterproof lintels made of clay soil, crushed stone, concrete and other materials.
Complex of construction works culverts includes: preparatory work, excavation, preparation of bases for foundations, foundations, pipe body installation, waterproofing. Before the construction of pipes begins, the design organization must fix in kind and hand over according to the act construction organization in the presence of the customer, the point of intersection of the axis of the embankment and the longitudinal axis of the pipe, required amount leading signs fixing the longitudinal OSB of the pipe and the high-altitude benchmark (Fig. 9.5), clear and plan the construction site, arrange drainage systems and entrances, start and place materials according to a plan previously developed and drawn on a scale of 1:500 or 1:200 construction site. The construction site plan (Fig. 9.6) is compiled on the basis of decisions made in standard project production of works.
Rice. 9.5. Scheme of fixing the location of the pipe on the route:
1 - outriggers (stakes); 2 - point and gatehouse with the inscription "axis", "picket" and "plus"; 3 - benchmark
Rice. 9.6. Site plan for the construction of a rectangular pipe:
1 - links of the body of the pipe and heads; 2 - blocks of sloping wings; 3- foundation slabs; 4 - box with cement; 5 - tank with water; 6 - sand; 7 - crushed stone; 8 - concrete mixer; 9 - power plant; 10 - tool storage trailer; I CT, II CT, III CT - parking places of the crane when driving installation work; α min , α max - minimum and maximum angles of rotation of the crane boom during installation of the pipe body links; l booms - the maximum reach of the boom, at which it is possible to install the links of the pipe body
From the axis of the pipe, the contour of the pit is outlined and fixed with metal stakes. Depending on the scope of work, the nature of the soil, the shape of the pit and other local conditions, the development of soils in the pit is provided for by: bulldozers, hydraulic backhoes with a bucket with a capacity of 0.15 ... 0.65 m 3 or cranes with clamshell equipment. When digging pits under water and in unstable water-saturated soils, soil jumpers, bottomless boxes or sheet piles with drainage are arranged. The top of the sheet piling should be 0.2…0.4 m above the maximum level ground water, and for channel supports - 0.7 m above the accepted working horizon of water in the river. In winter, with natural freezing of soils, it is allowed to develop pits up to 4 m deep without fastening. The pits are developed with a shortfall of 10 ... 20 cm to the design marks. The final cleaning of the bottom of the pit is carried out manually immediately before the installation of the foundation. Pit pits with a length of more than 20 m in unstable soils and in the presence of groundwater are developed section by section. The bottom of the pit in the longitudinal direction under the block foundation of the pipe is planned along an arc of a circle. In this case, the magnitude of the construction lift depends on the type of soil and the height of the embankment. The construction rise along the axis of the embankment for foundations made of sandy loam, loam and clay is taken equal to 1/40, and for sandy and gravel soils - 1/80 of the height of the embankment. After acceptance of the pit, crushed stone preparation is arranged. Crushed stone is brought in by dump trucks and unloaded into buckets, and then by a crane into the pit with a layer of 10 cm thick and compacted with pneumatic rammers. The marks of the top of the rubble are checked with a level. The rubble is leveled by hand with shovels.
Installation of reinforced concrete pipes. Before the start of installation work, at a distance of I m from the pit, a cast-off of boards and beams is arranged, indicating on it the axis of the pipe, the contours of the foundation and other dimensions.
The installation of pipes begins with the installation of the foundation in the direction from the outlet to the inlet head. First, the lower row of foundation blocks of the heads is laid with a crane to the level of the sole of the foundation of the pipe body. Then they fill it with a sand-gravel mixture and pour the bevels of the shallow part of the pit with a deeper one with cement mortar. The blocks of the upper part of the foundation are laid in rows. In case of sectional excavation of the pit, the installation of the foundation is carried out to the entire height within the section. The blocks cleaned of dirt are laid on a layer of cement mortar grade not lower than 150 with a thickness of 1 ... 2 cm. The deviation in the rows in height should not exceed 5 mm. The vertical seams between the blocks are filled with mortar. During installation, the horizontal rows within the section and the slope of the pipe are checked. Backfilling of the sinuses of the pit is carried out after the acceptance of the foundation. Backfilling is carried out in layers 15 ... 20 cm thick with thorough compaction of the soil in each layer with electric rammers. Installation of pipe foundations on slopes is carried out in sections 3 ... 4 m long, starting from the foundation of the outlet head
The installation of the heads and the pipe body begins with the outlet head. Head blocks are installed first. When installing portal walls and sloping wings of the head, braces or inventory struts are used. Then the pipe links are mounted using special clamps or brackets. Round links are mounted on curved blocks. To ensure the necessary clearance of 2 cm, the links are placed on wooden wedges. A mortar with a draft of a cone of 11 ... 13 cm is first laid and compacted on one side of the link, making it appear on the other side. The missing amount of solution is supplemented.
When laying the links of rectangular pipes, it is necessary to ensure their tight support on the foundation slabs. It is impossible to knock out or wedge the links with rubble. This can lead to damage and even destruction of the links. Seams 1 cm wide are left between pipe links, and 3 cm between sections (3 ... 4 links). Interfering mounting loops are cut off with autogenous. Cutting and bending loops is prohibited.
The seams between the links are filled with tow impregnated with bitumen (Fig. 9.7). And then all the seams, except for deformation ones, are filled from the inside with cement mortar grade 300. C outer side they are filled with bitumen. Before waterproofing, the surface of the pipe is cleaned.
As a glued waterproofing, a bitumen-impregnated fabric or a fiberglass mesh is used, two layers of which are laid on a layer of hot bituminous mastic and the laid layers are also covered with it from above.
Coating waterproofing consists of two layers of hot or cold bituminous mastic with a thickness of 1.5 ... 3 mm. It is applied to the surface of the pipe primed with varnish. When doing work in winter time apply internal heating pipes. The ends of the pipe are closed with shields, and its outer surface is insulated.
Rice. 9.7. Pasted over and coating waterproofing:
a - seam with pipe links; b - intersection seam of pipes on foundations; 1 - link; 2 - glued link insulation; 3 - bituminous mastic; 4 - coating; 5 - tow; 6 - stitching
The installed pipe is covered with soil. The height of the backfill should be 0.5 m above the pipe, and the width on top should be equal to the width of the pipe block, the steepness of the slopes should not be steeper than 1:1. Backfilling is carried out in layers with soil compaction by electric rammers and rollers on pneumatic tires. In winter, the thickness of the backfill above the pipe is increased to 1 m and it is led with thawed, or better, draining soil. At the same time, they make sure that large stones, frozen clods of soil, ice floes and snow do not get into the backfill soil.
Fortifying and Finishing work produced after filling the subgrade to the design marks in accordance with the project.
Pipe installation works are carried out in-line by an integrated team consisting of three units of 4 people each. The first link performs preparatory and excavation, the second - installation, the third - waterproofing and backfilling the pipes with soil. Members of the brigade must be proficient in several professions.
Means of mechanization - bulldozers, self-propelled jib cranes with a lifting capacity of up to 15 tons, concrete mixers with a capacity of up to 100 liters, mobile power plants with a capacity of up to 8 kW, cars, pumping units, mobile units for heating bitumen, vibrators and electric rammers, rollers, etc.
Installation of metal culverts. On the planned and cleaned bottom of the pit, they fill and compact sand cushion a width of 1 m greater than the diameter of the pipe and a thickness of at least 0.4 m (Fig. 9.8). Sand from dump trucks is unloaded into a pit, leveled with a bulldozer and compacted with rollers or loaded dump trucks.
Rice. 9.8. Dumping a pillow under a metal pipe:
a - in two stages; 6 - with a preliminary arrangement of the bed; c - with backfilling of the zero layer; 1 - part of the pillow, backfilled before laying the pipe; 2 - the same after laying; 3 - zero layer
During the construction of the pillow, the necessary construction lift of the pipe tray is arranged. After the foundation is installed, impervious screens are arranged under the outermost sections of the pipe 2.8 m long. The thickness and width of the screens must correspond to the dimensions of the pillow. To form screens, the base under the extreme links is loosened, cement is added, thoroughly mixed and compacted by hand with rammers. Then the final layout of the base is made and, using a cast-off, a cord is pulled along the axis of the pipe.
Install a pipe from individual elements or after pre-assembly of sections, which are assembled either at a centralized assembly base or at the pipe construction site. The length of the sections is determined by the capabilities of the available transport. When loading and unloading elements and sections of the pipe, hemp ropes are used, and with steel slings, tarpaulin pads are used to prevent damage to the coating. It is forbidden to hook the elements with hooks of slings through the existing holes, to drop packages and sections from a height. When assembling a pipe from separate elements with three standard elements in a link, the lower elements are first laid along the axis of the pipe for the length of the section or pipe, connecting them with 3 ... 4 bolts. The longitudinal seams of the even links should be on one line, and the odd ones on the other (Fig. 9.9). Then two other elements of the link are also mounted on 3 ... 4 bolts in the middle of the longitudinal seam. Hole alignment is performed using crowbars, inserting them into adjacent holes. Three links from the assembled one put and tighten all the bolts. When assembling pipes of large diameter, transverse ties are used for temporary fastening of elements.
Rice. 9.9. Placement of joints of elements 1 ... 6 of the pipe
When pre-assembling sections from links, the elements are installed in vertical positions and connected to each other with 3 ... 4 bolts. The assembled links are connected in threes, and the three-link sections are connected with one intermediate link, receiving one seven-link assembly section or lash. Pipe sections are installed with a crane on a profiled base on wooden linings so that the longitudinal seams of the connected ends of the sections have the same overlap and are located at the same level. The distance between the ends of the sections should be equal to the useful width of the element - 910 mm. Then the sections are interconnected with standard connecting elements. Joints are overlapped in the same way as when joining links.
To stiffen the ends of the pipe, bordering corners 40x40x4 mm 4.7 m long are installed, which are attached to the links with bolts.
Upon completion of the quality control of installation work and cleaning of the pipe surface, an additional waterproofing coating of bituminous mastics is made. To cover 1 m 2 of the surface, 0.3 ... 0.4 kg of bituminous varnish and 2 ... 3 kg of mastic are consumed. Priming with varnish is carried out with a paint sprayer, avoiding clots, smudges and bubbles. Not later than 24 hours, a layer of bituminous mastic 2 mm thick is applied using a mobile bitumen installation. The quality of waterproofing works is documented by an act. After eliminating the shortcomings, but no later than three days, the pipe is backfilled with soil. Backfilling of corrugated metal pipes is carried out with sandy and coarse-grained soil with a particle size of up to 50 mm. Backfilling to a height of 0.5 m above the top of the pipe is done simultaneously on both sides in equal layers with careful compaction of each layer. The soil is compacted with a vibro-impact machine. For better soil compaction near the pipe, backfilling is carried out in inclined layers (Fig. 9.10). With a backfill height above the top of the pipe of 0.5 m, the load from machines passing over the pipe should not exceed 98 kN, with a backfill height of 0.8 m - 108 ... 196 kN.
The standard time for assembling sections from individual elements is 4.8 man-hours per 1 m of pipe, for laying sections on wooden spacers - 1.26 man-hours per 1 section, for assembling a pipe from sections - 6.5 people. -h per 1 joint, for the installation of a fringing corner - 1.4 man-hours for 1 head, for the installation of an additional protective layer with bituminous mastic - 0.3 man-hours per 1 m 2 of the pipe surface, for the installation of an impervious screen - 0 .99 man-hours per 1 m 3 (E5-3).
For the construction of one pipe with a diameter of 1.5 m and a length of 26.5 m, 7 hours will be required, including marking and preparatory work.
Rice. 9.10. Backfilling of a metal pipe with inclined layers and compaction:
1 - pipe; 2 - line of closest approach to the pipe; 3 - vibro-impact machine; 4 - bullet layer
Installation work
Composition of operations and controls
| Stages of work | Controlled Operations | Control(method, volume) | Documentation | |
| Preparatory work | Verify: Availability of a quality document for materials; Checking the marks, the width of the preparation of the base, the presence of pits with floor sockets; Cleaning the base from debris, dirt. |
Visual Visual |
Passports (certificates), general work log | |
| Pipeline installation | To control: The quality of pipe support throughout its entire length on the base; Correctness of pipeline laying according to the project; Slopes of laid pipes; Compliance with the technology of installation and sealing of joints. |
Technical inspection Measuring Measuring, technical inspection |
General magazine | |
| Acceptance pipelines |
Verify: The quality of the work performed; Pipeline testing; Compliance of backfilling of pipelines with the project. |
Measuring, technical inspection |
General work log. The act of testing pipelines. Certificate of inspection of hidden works | |
| Control and measuring tools: level, building level, metal ruler, density meter GRPT-2, moisture meter PNNV-1. | ||||
| Operational control is carried out by: a foreman (foreman), a surveyor - in the process of performing work. Acceptance control is carried out by: employees of the quality service, foreman (foreman), representatives of the technical supervision of the customer. | ||||
Technical requirements
SNiP 3.05.04-85* p. 3.6, 3.51, 3.45, 3.46, tab. one
The size of the gap between the ends of the pipes to be connected should be taken for pipes with a diameter of:
Up to 700mm -8-12mm;
Over 700 mm - 15-18 mm.
The dimensions of the elements for sealing the butt joint of reinforced concrete and concrete non-pressure pipes must correspond to the values \u200b\u200bgiven in the table.
The maximum deviations from the design position of the marks of the trays of non-pressure pipes should not exceed +5 mm.
Requirements for the quality of the materials used
GOST 12586.0-83*. Pipes pressure head reinforced concrete vibrohydropressed. Deviations of the actual dimensions of pipes of types RT, RTP, FT and FTP. Specifications.
The same for types RTB, RTS, RTPB, RTPS.
The outer and inner surface of the pipes must meet the requirements:
No cracks are allowed on the inside and outer surface pipes;
Shells, sags and chips of concrete on the inner surface with a depth (height) of not more than 3 mm and a length and width of not more than 20 mm.
Work instructions
SNiP 3.05.04-85* p. 3.3, 3.4, 3.5, 3.9, 3.12, 3.52, 3.54
Installation of pipelines must be carried out in accordance with the project for the production of works and technological maps after checking the conformity with the project of the dimensions of the trench, fixing the walls, bottom marks and when laying above ground - supporting structures. The results of the check should be reflected in the work log.
Socket-type pipes of non-pressure pipelines should, as a rule, be laid up the slope.
The straightness of the sections of free-flow pipelines between adjacent wells, provided for by the project, should be controlled by looking at the light with a mirror before and after backfilling the trench. When viewing a pipeline of circular cross section, the circle visible in the mirror must have the correct shape.
The permissible horizontal deviation from the circle shape should be no more than 1/4 of the pipeline diameter, but not more than 50 mm in each direction. Deviations from correct form vertical circles are not allowed.
When laying pipelines on a straight section of the route, the connected ends of adjacent pipes must be centered so that the width of the socket gap is the same around the entire circumference.
To seal (seal) butt joints of pipelines, sealing and “locking” materials, as well as sealants according to the project, should be used.
Butt joints of pipes supplied without rubber rings should be sealed with hemp resin or bituminous strand with asbestos-cement mixture as well as polysulfide (thiokol) sealants.
The gaps between the stop surface of the sockets and the ends of the pipes in pipelines with a diameter of 1000 mm or more should be sealed from the inside with cement mortar. The brand of cement is determined by the project.
Connection of reinforced concrete and concrete pipes with pipe fittings and metal pipes should be carried out using steel inserts or reinforced concrete fittings made according to the project.
Reinforced concrete pipes are often used for laying sewer and waste pipes. Unlike steel pipes, a reinforced concrete product exhibits corrosion resistance, is able to maintain internal smooth surface for a long time, is a dielectric and contains a small amount of metal, which significantly reduces the cost of durable products in operation.
The installation of reinforced concrete pipes begins with the delivery of products to the installation site and the laying out of products along the trench. After that, they are fed directly to the installation site. Delivery is usually via railway transport to the storage location. Then, on powerful tractors, which are equipped with specialized trailers, the pipes are transported directly to the laying site.
At the very beginning, before laying the reinforced concrete pipe, a concrete stop is erected to ensure a stable position for the first pipes when they are joined. Before installation, mark on the smooth end of the product the distance at which the pipe will be inserted into the socket of the previously laid part of the pipeline. Lowering with cranes into a trench, reinforced concrete products are laid on a pre-prepared base. A rubber ring is installed at the end of the pipe sleeve, after which the reinforced concrete product is inserted into the socket of the already installed pipe. Then check the correctness of the installation.
After laying the reinforced concrete pipe, the joint is sealed. Socket butt joints of pipes without a rubber ring are sealed with a bituminized or resin hemp strand in combination with asbestos cement. Mastic-sealants are also used, which provide water resistance, strength and elasticity of the butt joint. Seam pipes are sealed with cement-sand mortar, bitumen-rubber gaskets, asphalt mastic and other materials. As antifreeze additive for mixtures that are used to seal the joint, sodium chloride, sodium nitrite, potash and calcium chloride are used.
The finished unfilled area is subjected to a preliminary test. If the pipe diameter is large enough, only butt joints are tested. After completion of all stages of installation, backfilling of this section of the pipeline is carried out. Then comes the final test.
Mounting reinforced concrete pipeline is carried out using a shooting crane, which is installed in the middle of the pipe to be laid. reinforced concrete pipe is captured by slings, and fed forward by sockets in the course of pipeline installation. It is important to adhere to the mandatory condition - you need to supply pipes against the flow of fluid.
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