GB 50268-1997 Code for water supply and drainage pipeline engineering and acceptance
Some standard content:
National Standard of the People's Republic of China
Specification for Construction and Acceptance of Water Supply and Drainage Pipeline Projects Article Explanation
GH50268-97
1 General
1.0.1 Since the founding of the People's Republic of China, the former State Construction Commission issued the "Interim Technical Specification for Construction and Acceptance of Building Installation Projects" (No. 1 External Pipeline Project) in 1956, which has been actively used for water supply and drainage projects. It includes professional pipelines and water supply and drainage buildings: Among them, the construction and acceptance of water supply and drainage pipeline projects only have some standard provisions. With the continuous improvement of water supply and drainage pipeline construction technology, the renewal of construction machinery and equipment, and the innovation of pipe varieties and structures, the original 1956 "Interim Technical Specification for Construction and Acceptance of Building Installation Projects" [No. 2 External Pipeline Project] is that it can no longer meet the current needs of water supply and drainage pipeline construction. In order to ensure the quality of the project. In order to improve the construction environment and economic benefits: this specification is specially formulated:
1.0.2 This specification is used for the general water supply and drainage engineering of the exterior of buildings. It specifically stipulates the acceptance of the prefabricated metal pipes and non-metallic pipes used in towns and industrial areas, brick, white concrete block masonry, existing concrete pipes, prefabricated assembled pipes, non-grooved pipes and pipes in bottom structure construction, inverted siphon pipes and auxiliary structures, etc. 1.0.3 This article is written according to the design requirements of the water supply and drainage pipeline engineering. Before construction, the construction unit should first be familiar with the design documents and construction drawings, deeply understand the design requirements, and carefully construct according to the drawings during construction. In particular, the location and elevation of the pipeline should be determined by the design unit through hydraulic calculations, and take into account the requirements of parallel or intersection with other professional pipelines. The design requirements should be met during construction:
When the construction unit needs to change the design due to design errors, material substitution, construction conditions and other rationalization suggestions, it should follow the relevant procedures: For local changes that do not affect the budget of the next project, the superior unit and the design unit can generally negotiate and make negotiation requirements: If there are major changes, the consent of the construction unit is also required, and the design unit shall submit a formal design change approval document. In short, there should be certain procedures and documents for changing the design. 1.1.4 There are many types of pipes, pipe accessories and other materials used in the water supply and ice removal pipeline. The product specifications of national and local factories are different, and the quality is good or bad. If they cannot meet the standards, it will affect the project and its use. For this reason, general materials, pipe fittings and other materials should be inspected according to national or local product standards and can only be used after they are qualified: In order to protect people’s health, pipes that affect water for daily use are prohibited. 1.0.5 The contents of this regulation are: -1. The relevant standards and regulations issued by the state (see Table 1.1); -2. The relevant regulations issued by local governments. In the construction, effective measures shall be formulated for these statutory documents to ensure that all personnel abide by these regulations, and a special agency shall be set up to conduct rectification and inspection:
List of standards and regulations issued by the state 1.1 International standard number, branch number or date of issuance! Name
State Council on the issuance of "Notice on Strengthening Enterprise Production Safety"
State Economic and Trade Commission No. 244
2: (75) General Labor Union No. 24
GEI16-87
GEF39-90
State Land Administration Order No. 22
December 26, (89)
GB50194-93
February 7, 1987 [
1582
Safety work knowledge: Several regulations of the State Council on strengthening the safety work of enterprises in production
Moreover, the State Council has made a thorough implementation of the "Regulations of the State Council on Strengthening the Safety Work of Enterprises in Production" and other regulations
Labor Protection Law
Model for Waterproof Design of Buildings
Fire Protection Code for Design of Rural Buildings
People's Republic of China Environmental Protection
Construction Engineering Construction Sites and Their Uses
Electrical Safety Code
The State Council has issued the Regulations on the Safety Management of Hazardous Chemicals
Ten Directives of the Ministry of Labor or Personnel This specification is compiled according to the characteristics of this profession. It is impossible to cover all the contents. Some contents will no longer be repeated with the relevant national standards and specifications. This article stipulates: First, it refers to the construction of water supply and drainage pipeline projects such as earthwork, foundation, steel embedded concrete, masonry and splash concrete block construction, pipeline installation and waterproofing, anti-magnetic and other downstream projects. In addition to complying with the provisions of this specification, it should also be implemented in accordance with the relevant national standards and specifications; second, it refers to the construction of water supply and drainage pipeline projects in special areas: such as collapsible loess, expansive soil, soft soil, etc., which should be implemented in accordance with the provisions of the relevant national standards and specifications. The main national existing standards and specifications that are different from this specification are listed in Table 1.2. Table of Contents of Current National Standards and Specifications 1.2 Serial Number Standard, Specification Abbreviation
GFJ14t—90
GBJ13—86
GHJ14—87
CJJ8—85
GB/20L--83
Construction and Acceptance Specification for Water Supply and Drainage Structures
Design Specification for Water Supply and Drainage Structures
Design Specification for Outdoor Water Networks
Specification for Outdoor Drainage Facilities
Urban Measurement Specification
1 Construction and Acceptance Specification for Water Supply and Drainage Engineering
Academic Standards, Specification Catalog
71GRJ202 --3
8 (G1203-83
3204--92
FH541205·95
G15[206—83
GBr208-83
GBJ108—R7
TJ212--76
(6J235-·52
G (7---87
G/32 1 90
G13--s
G382—hs
23 : GB11337—89
G53985--NS
CE6417—86
Code for the engineering and acceptance of foundation and foundation
Code for the engineering and acceptance of brick and slab foundation
Code for the engineering and acceptance of concrete structures
Code for the thermal engineering and acceptance of steel structures
Technical conclusion and acceptance of waterproof projects
Technical implementation of waterproof projects
Technical implementation of waterproof projects
Technical implementation of waterproof projects
Technical code for foundation treatment of buildings
1 Industrial pipelines: construction and acceptance standard
(Metal pipe reverse end)
Field equipment industrial pipelines Welding engineering film
Reform acceptance specification
Steel connection and transmission and specification
Concrete three-point test and evaluation standard
Pre-acceleration ten-point quality inspection and comparison
Municipal drainage pipe case "process quality plan inspection and evaluation
Determination method
First follow the main long-term performance of concrete, that is, durability
Energy test method
Visual gaze: Concrete 1 anti-le worry test
Will have a method
Course requirements for welding skin gas protection
Groove about the basic form and size
Pot baking welding weld defect classification and its points
26131.5017-03 Pressure steel pipe certification and acceptance specification TJ32-78
2K GU25--90
Geil12-87
GR50221—
Outdoor water supply and drainage and gas heating engineering
Anti-dew design standard
Mixed road construction policy specification
Zhangshang area building technical specification
Steel structure engineering bearing capacity inspection and evaluation standard
G74985
Sanitary standard for drinking water
2 Construction preparation
The content of this code is partly based on the "Code for Construction and Acceptance of Water Supply and Drainage Structures" (BJ14I-90): "Water Supply and Drainage Structure Engineering" is replaced by "Water Supply and Drainage Pipeline Engineering Code" to adapt to the applicable scope of this code. There are no additions to the content of the clauses, and there are some revisions in the wording. For example, in Section 2.4, it is stipulated that "the temporary level point of the pipeline shall not be less than 1α for every 2Mhm", which is the content added to the standard.
3 Trench excavation and drainage
3.1 Construction drainage
The provisions of this section are consistent with the current national standard "Construction and Acceptance Code for Water Supply and Drainage Structures [GB]] 41-9. In view of the slightly different characteristics of the structure and pipeline construction, some provisions have been replaced according to the requirements of pipeline construction: 3.1.3 When the pipeline is not in good condition, it is strictly forbidden to stop drainage. After the pipeline is installed, when the pipeline is not full of water, stop drainage for one month. After one month, the groundwater level may float the pipeline. 3.1.6 The pipeline is line-shaped, so this article stipulates that "the drainage well is outside the trench specification, and its distance should not be too large". 3.2 Trench excavation 3.2.1 The design opening width of the bottom of the trench for water supply pipes should include the outer edge width of the pipeline structure, the working surface width on both sides of the pipeline, the width of the support, the width of the existing template, etc. If the pipeline has an external waterproof layer applied on site or uses open ditch drainage, the excavation width should be increased: The bottom excavation width of this regulation is basically consistent with the construction and inspection code of explosive engineering (GEI201-83).
3,2.3 The trench digging method can be done manually or mechanically according to specific conditions: When using manual excavation, if the trench is deep and the soil cannot be thrown out of the trench directly, layered excavation should be adopted, and measures such as leaving platforms between layers should be taken to facilitate the transportation of soil and also have the functions of safety and convenience for installation. The degree of layering is based on the length of the shovel that can throw the soil out of the trench with the height of the human body. According to experience, this height should not exceed 21. If the trench depth is greater than 2m but not more than 3m, it can be set up as a soil transfer station without layering. 3.2.4 This article is for the purpose of piling soil on both sides of the trench, and when there are equipment and two machines, in order to ensure the stability of the trench and not affect the construction, it should be noted that the pile height and distance from the soil pile specified in Article 3.2.4 are the limits that should not be exceeded even if the pile and other loads have a great impact on the stability of the reinforced wall.
3.2, During the auxiliary design, in order to control the pipe line, the bottom elevation of the groove and the elevation of the pipe clamp, stop joints, slope plates or other methods can be used. The slope plate is easy to make, easy to operate, and has many uses. The slope plate is marked with the position of the pipeline centerline and the bottom elevation. In order to prevent the plate from deforming, it is recommended to use a material with a certain rigidity that is not easy to deform. In order to prevent displacement, it should be set firmly. The spacing of the slope plate is mainly determined by the error caused by the droop of the pull line and the accuracy required for the height measurement: some enterprise standards stipulate that for non-pressure pipelines, the spacing of the slope plates is generally not more than 10m; for pressure pipelines, it is not more than 20m. The spacing of the slope plate should not be greater than 2m. For different pipelines, the installation distance should be selected under the condition of less than 20 meters. The vertical line should not be too long to reduce the measurement error. Therefore, it is stipulated that the height of the slope plate from the bottom of the tank should not be greater than 3ms. When the trench depth is not more than 3m, the slope plate can be buried at the top of the trench wall. When the depth is greater than 3pat, the trench river is set at the platform between the layered excavation layers. When slope cutting and grooving, it can be set on the trench wall.
3.2.6 After trench excavation, there are often already built water supply pipes, drainage pipes, cable pipe blocks and cultural relics, etc. If they are not properly maintained, it is easy to cause accidents. For this reason, this regulation is tried for this frequently encountered situation. When encountering pipelines, etc., it is required to take protective measures first: ensure that the pipeline is not damaged and its normal use is not affected: "Notify the relevant units" means that after the pipeline is exposed, the relevant units will be notified in time, and further protective and treatment measures will be taken: 3.3 Trench support 3.3.1 Support engineering is an important project related to safety construction when the trench is excavated (the slope is about 0), which includes the design of the support, maintenance and removal. These internal penetrations must be carefully designed and carefully implemented In order to avoid instability and landslides that affect construction and even cause personal safety accidents. The design of the support should ensure the stability of the entire trench. The relevant factors mainly include the nature of the soil layer in which the trench is located, the groundwater level, the depth and width of the trench, and the load conditions. The design method can generally be based on relevant data.
The trench belt of the water supply and drainage pipeline adopts support plates and dynamic steel plate support: in some cases, anchor rods, cast-in-place hanging or other types of support structures are used. The provisions of this article apply to various types of support and retaining structures, but in the following relevant provisions, only the support plates and steel plates used are used. The design, construction, maintenance and removal of sheet pile support have been specifically regulated. Other types of support should be specified in the construction design. It should also be mentioned that the "support plate connection" here refers to the support structure installed after the trench excavation reaches a certain depth, which is composed of horizontally or vertically arranged supports, longitudinal beams or transverse beams and transverse beams to protect the stability of the trench. Among them,
Support plate: refers to the retaining plate close to the trench: Longitudinal beam or transverse beam: refers to the support plate arranged horizontally or horizontally:
Transverse brace: refers to the horizontal auxiliary rod that crosses the trench and supports the longitudinal beam or beam.
According to the design of the support plate, it can be divided into close-packed support (abbreviated as "close-packed support") and sparsely packed support (abbreviated as "sparsely packed support"). Alternative support means that there is no gap between the support plates; sparsely packed support means that there is a gap between the sample plates, and the size of the gap is determined according to the design, and even the longitudinal beam or the flame is omitted, so that the cross brace directly supports the support plate. The support plate support layout is shown in Figure 3.1 to 3.2, (.t)
Figure 3.1 Layout of support plates
(α) Non-support plate: () Vertical push plate
1 Support plate; 2-longitudinal beam: 3-cross beam: 4-cross brace C
at agaat
Figure 3.2 Sparse support plate cover
(a) Single plate support; (6) Common: () Ship support 1--palm plate; 2---cross brace: 3--cross brace
When using steel, it can be designed as a single anchor multi-layer support sheet pile support. Its surface layout can be t
Figure 3.3 Steel plate support pattern surface cover
(α) Interval refers to the row: () No interval full arrangement: () Intersection refers to the dead 1-average center line; 2---Steel sheet pile
Interval arrangement, no interval arrangement and bite arrangement. This back row shadow Wu Ru space 3.3 As shown,
3.3.4 When using baffle support, the support must be installed in time: This is an important issue when using floating plate support. According to Article 3.5.4 of the "1 Party and Refinery Engineering Construction Acceptance Code" (G201-83), the quality of the seven materials is about the same and the groundwater is not allowed to reach the bottom of the ditch or the bottom of the ditch. The depth of the support should not exceed the specified regulations. Density: medium-density sand and stone (abandoned fill is protective) F
hard help, the expected light industry adhesive ten skin industry adhesive 1.25:1
hard plastic, the adhesive rate and material soil (abandoned fill is hungry soil!
The third provision of this article is that the depth of the trench support is not random.
It needs to be emphasized that when the trench excavation depth reaches or exceeds the above, it may not necessarily cause a landslide: this phenomenon is mainly related to the conditions of the layer where the trench is located: it is difficult to accurately determine its configuration. The law of the ground is that it is easy to ignore the importance of support during work, and the technical requirements should not be met: therefore, "no time to install" support is a necessary indicator to ensure the safety of the construction. The trench excavation depth should be reached when the support is not rigid, and the support should be coordinated with the trench to continue to be excavated. The support time cannot be delayed for any pressure.
3.3.% The provisions of this article are measures to protect underground pipes or supply pipelines. When using the core plate, the edge of the plate under the pipeline should be close to the road. The purpose is to make the lower edge of the mixing plate on the three sides of the pipeline have a certain distance from the pre-surface of the road, so that the support on the road will not sink and will not increase the load on the pipeline:
33.12 In order to facilitate going up and down the trench, people often climb the support, which may cause human safety accidents. In order to prevent such accidents: 1. The lower step should be equipped with a safety ladder, and the climbers should not help to support the upper and lower steps.
3.3.13 The trench depth of the excavation trench exceeds 2r, but the original layer is not excavated in layers. The trench is a turntable. The soil plate is a beam-mounted horizontal support, which also includes the weight of one person waiting to be transported up and operated. In this case, Xie Shishan is removed from the leveling box! In addition to the shovel, check whether the connection with the cross brace is firm, and whether the cross brace supporting the earth slab is reinforced to ensure safety. 3.3.14 This article stipulates that before removing the support, a safety inspection should be carried out on the buildings on both sides of the trench, such as the trench waist and the trench handle, whether the building and structure have settled, whether the support has been displaced or loosened, etc., to determine the possible consequences of removing the support. If necessary, the specific method and safety details of the removed support should be formulated and implemented before the support is removed, so as to ensure the safety of the project and protect the nearby buildings and structures. 1.3.3.15 It is very important to ensure the safety of the support and protect the nearby buildings and structures: for this reason, this article has 4 regulations for the removal of the support, among which 3.3.15.The "replacement and dismantling method" in Article 4 refers to the removal of horizontally arranged close-packed plates. The height of the removal should be less than 206km (some units consider it to be 206km). Before the removal, the replaced beams and supports should be prepared.
3.4 Pipeline intersection treatment
When the water pipeline is installed, it will intersect with the existing or under-construction water supply, drainage, coal, heat, cable and other underground roads. The design should be specifically designed for the treatment of these intersections. The construction unit shall construct according to the provisions of the design documents. Some pipelines, especially those with smaller diameters, are already in the pipeline and many of them are discovered during trench excavation. In this case, if the construction unit is asked to handle it, it will not be beneficial to the design and management units. The following clauses are based on the design and construction regulations before compilation: .4,1 Article divides the pipeline intersection treatment into 3 types of situations.
, Handle according to the design space
For those pipeline intersections with large operations, complex technical requirements or other requirements that cannot be handled by the construction unit in advance, they should be handled according to the design documents. If the design documents do not have provisions, the construction unit can handle the intersection in advance after the design unit provides the design documents.
If the design documents do not have provisions, the construction unit can handle the existing pipeline intersections before the construction site, which is limited to the opening conditions specified in Articles 3.4.2 to 3.45 of this code. It should promptly notify the relevant units. Obviously, if the design documents have specific provisions for this type of pipeline intersection, it should be handled according to the design documents. 3. Consult with the design unit to handle
When changing If the management document does not have provisions, and the document does not comply with the requirements of Articles 3.4.2 to 3.4.5 of this code, the implementation unit shall negotiate with the design unit to deal with it.
3.5 Trench backfill
The conditions that should be met before the trench is backfilled include two aspects: 3.5.1
Structural strength and water pressure test. The conditions that should be met by the wooden strips facing the micro-channel structure are: What needs to be mentioned is: 1. The cover plate (pre-fill of rectangular pipes and canals) is prefabricated, and according to the frequency variation of the plate and practical experience, the backfill is backfilled with a dense cover. In particular: the backfill on both sides of the canal is not solid, and the side wall is cracked: Therefore, Article 3.5.1.3 stipulates that the cover plate must be installed before backfilling:
2. For rectangular pipes and canals, the technical pipe racks that are cast on site, forcedly built or assembled on site with prefabricated components: at the same time If cracks, displacement or fire instability may occur during backfilling, measures should be taken before backfilling. The specific method depends on the actual situation. Generally, the pipe can be supported and fixed inside the canal. The pipe is used for temperature control during water test to eliminate the influence of ambient temperature change on the water level in the pipe and prevent the displacement of the pipe. In addition, the joint should not be filled to facilitate leakage inspection. Article 3.5.2.2 stipulates that for steel pipes with a pressure of more than 90MW, measures should be taken to control the lateral deformation of the pipe. This is the same as the pressure of the steel pipe. The vertical diameter of the pipe is reduced and the horizontal diameter is increased due to the large lateral earth pressure. The pipe of the steel pipe is thinner and has a larger vertical deformation than reinforced concrete pipes or brick-built pipes under the same earthwork conditions. When the deformation is likely to exceed its allowable value, measures can be taken to control the deformation: one measure is to set temporary axial support inside the tunnel before backfilling, so that the vertical diameter of the tunnel is slightly larger to reserve the deformation volume, and then remove the support after backfilling on both sides of the pipeline. This method is an effective measure to control the axial deformation of the pipeline:
3.5.3 The pressure used in the non-pipeline water test is reduced, and the influence of ambient temperature is generally not considered, and no insulation is required. On the other hand, in addition to the joints of steel-faced concrete and broken stone construction, pipe protection or hemp can also be carried out to detect leakage. Therefore, it is stipulated that when backfilling after the water moistening test, the bottom pipe should be filled with fine particles within 5m. When using stone, dead stone, sand and other materials, it is not appropriate to make specific regulations due to the large differences in specifications and quality of these materials. The requirements shall be implemented according to the specific design specifications of the project. 3.5.5 Articles 3.5.5 to 3.5.7 compare the regulations made in several drawings made during the backfill and compaction: including the compaction time, the amount of water contained in the layer, the thickness of the layer and the number of compaction times. In the foundation site, if the type of backfill soil is determined, and the compaction tools are also determined, the three factors that affect the compaction degree are the water content of the soil material, the thickness and the number of compaction times. This article is a practical method to control the water content. The water content of soil material has a great influence on compaction. The relationship line between the maximum density obtained from the experimental test and its corresponding optimum water content shows that before and after the deviation from the maximum density, the corresponding water content is less than or equal to the optimum content. The greater the distance from the maximum density, the greater the difference in the corresponding water content. This phenomenon shows that when using the same compaction tools, the same thickness and compaction times, the more the water content deviates from the optimum water content, the more compaction will be required. Therefore, it is very important to control the water content when compacting and keep it close to the maximum water content. tt||3.5.6 The degree of auxiliary coverage of the solid fill is related to the load intensity of the compaction tool and the required compaction degree: the load intensity is small or the required compaction degree is high: the original degree of laying is small; otherwise, it can be larger: the actual determination of the virtual laying thickness of wooden strips for different compaction expectations is determined based on the relevant specifications and reference to some implementation specifications, so that it can be selected when 1.
3.5.7 The compaction avoidance number of backfill soil is determined by the on-site compaction test, and the range of compaction times is not given. When a certain compactor is used under the conditions of requiring a certain degree of compaction, the actual compaction achieved is related to its content and the degree of compaction, and depends on the compaction number. As mentioned above, when the effective compaction depth begins to reach a certain limit, the compaction increases with the number of passes. After increasing to a certain degree, the compaction no longer increases when the number of passes is increased. This clearly shows that when a higher degree of compaction is required, it is not possible to increase the compaction number as required, adjust the water volume or thickness, or even replace the compactor with a larger load. Therefore, the compaction number should be determined through on-site compaction tests. On-site compaction tests are simple and easy to carry out. The results obtained are reliable and have obvious safety significance for guiding construction work: Therefore, this article stipulates that the compaction data should be confirmed through field tests, and the correct compaction tools should be selected according to the material conditions on site, combined with the moisture content of the material, and the compaction data obtained through tests. 3.5.8 When using heavy-duty tools to compact backfill soil, in order to avoid moving pipes, there must be a cover of compacted backfill in advance to reduce the load of the compaction tool on the main body to a level that does not damage the pipe. Due to the different types and specifications of concrete tools and different bearing capacities of pipes, this article stipulates that the design of the material can refer to the "Design Code for Drainage Structure Engineering" (GBJ69-84) Calculation based on relevant regulations or other relevant data.
This article is applicable not only to compaction tools, but also to situations where trucks, cranes or other vehicles are driving or stopping on the backfill soil.
3.5.12 Articles 3.5.12 to 3.5.15 are a set of regulations on the backfill compaction standards for water supply and drainage trenches. In addition to restoring the topography after burying the pipes, the trench backfill and solidification of water supply and drainage pipelines should also protect the road structure. In the backfill construction of the road surface, in addition to meeting the requirements of the soil foundation compaction, this article is based on several relevant professional specifications and combined with the actual situation of the backfill of the water supply and drainage pipeline trench, to recommend a suitable quality standard. The roadbed requirements and the protection of pipelines are determined by the standard of positive compaction.
The standard of the compaction degree of the backfill soil has two standards: light compaction and heavy compaction: the compaction of the good quality backfill soil is mainly based on the heavy compaction standard in the relevant specifications of urban roads, and the corresponding light standard is given: this series is the standard of the backfill soil of the backfill soil, and the provisions of these two standards are also given. It should be noted that the compaction of the backfill soil of the water supply and drainage pipeline trench is mostly based on light compaction engineering, and the light compaction standard is used as the standard. Except for those specified in this standard, the maximum density obtained by the light compaction test method is %
This series of compaction standards for backfill soil as roadbed is listed in Table 3.5 of Article 1.12. In addition, the compaction standard and the depth range from the bottom of the trench are basically consistent with the urban road design standard (CJJ37-90) and the urban road subgrade construction and acceptance specification (9F44-91). It should be noted that in order to protect the pipeline, the adjacent pipeline within the height range of the project cannot use a compaction tool: even if it can be used, it is difficult to achieve a higher compaction degree due to the presence of manual pipes. When the compaction degree has reached a high level, the compaction degree of the backfill soil above the pipe is also low. This is a practical problem. Table 3, 8.3 of the "Standard for Inspection and Assessment of Municipal Drainage Pipeline Quality" (CJJ3-90) stipulates that the compaction degree of the backfill within 50cm above the pipe should not be less than 85%, which has the effect of protecting the road. This is in line with the actual situation that the pipe is intended to achieve a higher compaction degree within the specified specification. However, this regulation does not meet the quality foundation compaction standard. Therefore, when formulating this specification, after consultation with relevant parties, special treatment was made for the compaction degree within the 25cm range above the pipe, that is, the surface sampling within this 25cm range has a compaction degree of less than 87%.
3.5.13 This article is specifically for the compaction standard of backfill on both sides of the pipeline. The points are as follows:
First, when the trench backfill is not used as a roadbed, the backfill compaction degree on both sides of the pipeline meets the requirements for protecting the pipeline. When the backfill is used as a roadbed, it should meet the requirements for roadbed compaction. When the requirement of foundation compaction is higher than the requirement of protecting pipeline compaction, the construction of roadbed compaction can meet both requirements. 2. Due to the different structures of pipelines, the compaction standards on both sides should also be different. In circular pipelines, this article classifies concrete pipelines, reinforced concrete pipelines and cast iron pipelines as categories, and stipulates that their minimum compaction should not be less than 90%; steel pipelines are generally thinner, so they are classified as category I as ductile iron pipelines, and their minimum compaction should not be less than 95%: There are also special cases. For example, the inner diameter of the ductile iron pipeline in a certain project is larger and the wall texture is thicker. Although it is not suitable for steel pipes, it is stipulated that the compaction on both sides should not be less than 10%. Therefore, for pipelines with special circumstances, the compaction on both sides should be implemented according to the design documents.
The structural design of the prefabricated circular pipeline is different from that of the prefabricated section. If the backfill soil of the pipeline trench is not used as the roadbed, the compaction degree of the backfill soil on both sides of the pipeline may vary depending on the structure. Therefore, if the design has regulations, find a way to implement it: if there is no design regulation, this regulation will not be violated by more than 0%: it is equivalent to the lower value of the compaction degree standard for both sides of the wind-shaped pipeline.
3.5.14 This regulation uses lime, sand, silica gravel and other materials for backfill. The following points are made: 1. The article lists several conditions under which original soil cannot be used for backfill. Among them, the shallowness of the pipeline, the low bearing capacity of the pipeline and the large load caused by compaction work. It is difficult to use these three conditions to determine whether the original soil cannot be used. For example, in order to protect the pipeline from damage, when the cover depth and the compaction work are relatively large, pipelines with different bearing capacities may have different treatment measures such as backfilling with original soil or not. It should also be explained that among these three conditions, "shallow cover" (or "shallow cover") is more prominent. This specification does not give a certain limit for "shallow cover", mainly considering that this limit is also affected by other conditions and is not a certain limit. Such regulations are conducive to specific treatment according to specific conditions, so that the measures taken can be more practical.
2. The article stipulates that lime soil, sand, gravel and other materials can be used for interfilling. Consult with the design unit. The consultation mentioned here refers to the consultation on the selection of backfill materials, quality requirements and required compaction standards.
2. Measures to strengthen the pipeline generally include increasing the support angle of the pipeline foundation, using concrete to encapsulate the pipeline or other measures. Obviously, the specific measures to be adopted should be specified in the design documents. 3.5.15 This article is a regulation on the compaction standard when the "medium loose side compaction method" is used for backfill soil above the pipe top.
The vertical load above the top of the pipeline is the main load in the design of the pipeline structure. Among them, the vertical soil pressure is the main factor. Therefore, the strength of the vertical soil pressure in the vertical space can be used to improve the bearing capacity of the pipeline: using the "medium loose side compaction method" to backfill is an effective measure to reduce the vertical soil pressure.
In the quality inspection of municipal drainage pipe project The "medium loose measurement and compaction method" is stipulated in the evaluation standard (Central Standard 3.5.1) and some local standards or enterprise standards, but they are slightly different. This article has the following explanations on the provisions of "medium loose measurement and compaction": First, this method is only applicable to the backfill soil of Hongcao, not the roadbed. When the backfill soil is used as the roadbed, the basic principle of "medium loose measurement and compaction" remains unchanged, but the specific regulations are different (see Article 3.5.12). Second, this article has clear provisions on the scope of "non-loose", that is, the quotient above the pipe is 50mm, and the width is the range limited by the outer edge spacing of the pipe structure: The compaction degree standard of the "medium loose" part should not be greater than 85% to ensure the relative "medium inspection". 3.5.16 The high water content source soil referred to in this article mainly refers to soft soil. But it also includes other soils with this property. The soil is high in water content. In order to achieve a relatively high compaction, the effective method of reducing its water content is often difficult to achieve due to construction sites, climatic conditions, period restrictions and other reasons. Therefore, this article stipulates that if the conditions for reducing the original water content are not met and the required compaction degree cannot be achieved, stone soil, sand, sand or other materials that can reach the required compaction degree should be filled.
3.5.17 In addition to preventing damage to the structure, the following two points should be noted in the implementation regulations for backfilling and compaction around the raised floor in this article: First, the raised floor within the road surface should be backfilled with stone soil, sand, gravel and other materials with low sedimentation to prevent large sedimentation and damage to the road surface;
Third, when working, the backfill should be symmetrical to the center of the road surface so that the lateral pressure on the road surface is symmetrically distributed to avoid damage to the structure. 4: Installation and laying of prefabricated pipes bzxz.net
4.1 Provisions
4.1.1 During the unloading and transportation of concrete or reinforced concrete, special attention should be paid to prevent damage to the interface parts. For steel pipes and ball suspension iron spans, damage to the inner and outer anti-magnetic layers should be prevented.
4.1.2 \ "Easy to use" means that the pile should be placed in a place that is convenient for loading and unloading and does not hinder traffic.
4.1.3 The rubber ring will age due to long-term exposure to ultraviolet radiation or close to heat sources; it will deteriorate when in contact with vapor, benzene, acetone, turpentine, acid, alkali, salt, carbon dioxide or placed in a place with electric spark discharge for a long time; it will be permanently deformed and reduce the water-stopping effect due to long-term squeezing.
4.1.6 Pipeline installation: First, the pipeline is laid from downstream to upstream. During installation, the bearing groove faces the installation direction. This construction is conducive to the stability of the pipeline. Second, the water in the pipeline can flow to the downstream. Third, the bearing joint adopts thermal pool materials and will not flow out. This arrangement of the two is particularly necessary for drainage pipelines: mountainous areas: water supply pipelines in ridges. The original water pipelines in the area are not necessarily laid according to this rule. Although the pipeline is a pressure pipeline, the water distribution pipeline is often arranged in a mesh shape. There is no upstream and downstream separation.
4,1.7 Table 4.1,7 Note 2 When the flexible mechanical connection is installed, the pre-solution method is used to install the movable chisel skin and the operation space of the wrench is about 0.
4.1.8 When transporting pipes in trenches, pipe joints can be used at the bottom of trenches to transport them manually in rolling order to avoid disturbing the natural foundation. 4.1.13 During rainy seasons, a rainwater diversion plan should be prepared first. Rainwater is very easy to flow into trenches, and mud may flow into pipes, causing pipe drifting accidents. Emergency measures to prevent pipe drifting include strengthening drainage in trenches. If necessary, water can be poured into pipes to reduce buoyancy. 4.1.14 After freezing, the elasticity of rubber pipes will be lost, affecting water pollution.
4.1.15 The temperature of pipe body is the change of air temperature. When the air temperature changes from negative temperature to positive temperature, the surface of the pipe body may still be in a non-negative state. At this time, if cement or cement mortar joint construction is carried out, it will still cause the flow of asbestos cement or cement mortar materials. This article stipulates that when the surface temperature of the valve is as low as -3, it is advisable to reverse the asbestos cement or cement mortar interface construction, and the bottom should be installed in winter.
4.1.19 Before installing the valve, a shoulder closing test must be performed to check whether the parts are flexible. Some valves are installed and then flushed. If they are still drowning after closing and operation, it is necessary to disassemble the valve body to check whether the groove is in compliance with the hook or the groove and the plate are not tight. It should be pointed out that for large-scale, especially imported exhaust valves! Be cautious when disassembling the inspection. Before disassembling, the structure and assembly combination of the valve must be fully understood before proceeding, so as not to cause the fan surface that is difficult to install after disassembly:
4.2 Steel pipe installation
4.2.1 Steel pipes for water supply and drainage are generally of larger diameter. Rectangular steel plates are often rolled or arc-shaped, and then welded together. The steel pipes processed by this process are rolled into steel pipes with straight welds. The deviation of the roundness, thickness, length, and end-to-end accuracy of steel has a great impact on the installation quality and construction progress of the pipeline. In order to ensure the quality of the work, this specification is based on the enterprise standards of the manufacturers in Beijing, Tianjin, and Shanghai. The adjacent current national standards and industry standards have formulated the allowable deviation indicators in Table 4, 2, 1. Rust depth greater than [mm, less than 2mm is considered severe corrosion. "Broken scar" refers to the wound whose depth is greater than the negative deviation of the thickness of the pipe wall. The negative deviation of the wall thickness of 8-25mm is 0.8nm
4.2.2 According to the size and number of each part of the quality pipe, the welding rod can be arranged in order, so that the deviation of the connection is reduced to the minimum, so as to achieve the standard of high engineering quality.
4.2.6 According to the properties of the welding fluid, the welding rod is divided into two categories: acidic welding rod and alkaline welding rod: the former has poor dynamic tolerance, while the latter has poor processability and good dynamic tolerance. No matter which welding rod is selected, it should be chemically or chemically the same as the parent material and have the same mechanical strength to ensure the safety of the workpiece. Under the premise of full coverage, the accompanying conditions and "technique" are considered. The conditions of the parts refer to the environment of the structure, such as temperature, positive force, corrosion state and stress conditions. Technique refers to the welding position, work complexity, ground wind conditions, degree of cleaning and worker operation proficiency, etc. Generally, acidic furnace rods are used to weld low-profile steel parts that are difficult to assemble, and energy-reducing welding rods are used to weld steel or parts with complex shapes, large thickness, poor working conditions and relatively important joints: no inclusions when welding Use of unacceptable welding rods, such as the Jie Xie induction system, will cause the welding performance to deteriorate, resulting in unstable current, increased flying jump, and easy production of defects such as pores and cracks in the weld. Or the use of alkaline welding rods will also produce harmful gases. Therefore, the welding rods are usually placed in an oven for ten hours, and then placed in a drying rack or heat preservation container for use at any time.
+.2.7 Beijing, Chong, Lu,,\zhou, butt welding of pipes adopts V-shaped slope, and the large 110mmT industrial pipeline is used in the village. |1 and acceptance specifications (G] 5235-82] standard V-shaped slope L [crew edge courtyard is 2mm, gas, hand this drive welding and gas shielded medium wall groove basic form Ma Jin (more than 98-8 stipulates that the plate strength is 326m, the clock edge is 1--4m, the gap is 0--3m: This specification combines the quality requirements of the final acceptance of the radiographic detection of various places, and proposes the provisions of Table 4.2.7 according to the relevant national standards.
4.2.8 "Internal smooth opening", refers to the ring when the door is To the seam, this series of equipment, industrial pipeline welding engineering and construction.L acceptance standard 3 ((236-82) Ming-level state tank regulations, compared with the northern and Wuhan technical regulations, the regulations are relatively wide. According to the principle that the standard should be based on the national standard, the regulations of the adjacent national standard are selected. 4.2,9 stipulates that the number of welds is set at the location where the circumferential stress is the smallest when the pipeline is loaded. The second is to facilitate maintenance. The third is to avoid welding chain concentration and improve The probability of cracks is still high. For example, the probability of cracks in the "cross" shaped weld is significantly higher than that of welds of other types of joints. 4.2.1 After the square hole is passed through the water, stress concentration will occur at the corners of the hole. Hanshi × project has opened a square hole and a round hole on the pipe. When the water is passed through, the square hole is cracked, and the threshold hole is sealed.
4.2.13 When welding long-distance pipelines, the pipe section is often first connected to the groove. The pipe section is placed in the groove. Therefore, the pipe is installed and the interfaces between the sections are fixed. When the sections are connected to the last part and the interface is welded, it is called a closed joint. The difference between the atmospheric temperature at that time and the lowest temperature of the day or the difference between the hydraulic temperature of the pipeline during operation will cause the pipeline temperature to deform. Because the pipe is under the influence of the obstacles, such as the three-way pipe, the pipe head, etc., it cannot expand and contract freely, and the pipeline will produce tension. For this reason, it is stipulated that the closed welding of the fixed end should be selected in the lower temperature. In some places, In order to avoid the incident of pipe breaking caused by closed welding, a stretchable joint is set at the closed mouth to initially eliminate the temperature. 4.2.14 This system absorbs the experience of the Dongzhao area and refers to the acceptance specification for the implementation of medium and low-pressure pipelines (Lianhua Jian 50274). 4.2.16 In order to make the greatest efforts to prove the strength of the pipeline, double-sided furnaces are used as much as possible for pipelines that can be entered and operated by ordinary people. The regulations of Beijing and Shanghai are as follows (Lumen <60hm, Beijing>0 rt)
4.2.7 Oil penetration test The quality requirements of steel pipe interfaces are as follows: For general water supply and drainage pipeline projects, this test can meet the requirements of single interface quality inspection. For more important pipelines, such as trunk pipes or water supply and drainage pipelines with human influence, the depth inspection and appearance inspection shall be carried out with reference to the provisions of grade 1 welds in the "Code for Construction and Acceptance of Industrial Pipeline Engineering" (GB123582) in various regions. 4.2,19 After the final inspection, when the installation method is connected, the pipeline will deform longitudinally. In order to avoid damaging the installation flange and its interface, the flange must be tightened before the adjacent flange and welding. 4.3 Steel pipes comply with internal and external anti-corrosion brain. 4.3,1 The steel wall is thin and the rigidity is small. During the installation process, lifting and transportation will cause large deformation. The prefabrication method is used to make the internal and external anti-corrosion layers. The loading, unloading and transportation should be carried out according to the regulations of 4.EE of this specification. The pipeline that uses the pipe first and then the internal anti-corrosion layer shall be tested by water pressure test. It is still qualified and the pipeline deformation is basically stable. Because of mechanical spraying, the spring trowel is used for spreading and pressing. If the vertical deformation is too large, the spreading force will be uneven, making the density of the cement sand anti-corrosion layer uneven, which will affect the quality of the second process. Use people.1 Spread cement mortar for anti-corrosion When applying the layer, such as before the water pressure test or backfilling, the anti-corrosion layer in the cement mortar will be opened due to large deformation during the water pressure test and backfilling.
.2 The quality of sand has a higher requirement on the quality of cement sand aggregate. Natural sand refers to river sand or sea sand. Its mud content is more stringent than that of mixed sand. In order to control the maximum content, it is generally screened and washed before use. Due to different ancestral and human pressure processes, there are specific requirements for the grading of cement sand. Due to different physical properties of raw materials and different construction experiences, this article stipulates the maximum particle size of sand. The grading can be selected in the cement mortar ratio.
4.3.3 Due to construction conditions, some projects use prefabrication to apply the anti-corrosion mortar in the following ways: adopt the method of strengthening the rigidity of the pipeline to overcome some deformation caused during the construction process Too much stirring will damage the corrosion layer in cement mortar. The rubbing method has been used in foreign countries since the 1930s. In China, it was first used in Shanghai, Dalian and other cities. The surface of the cement mortar anti-corrosion layer constructed by this method is smooth, smooth and uniform, and good results have been achieved. Beijing and Tianjin have used it in large-diameter pipelines with a limit of 230 meters or more, and the effect is also very good. When artificial mortar is constructed, it should be implemented in four layers, including the slurry layer, transition layer, leveling layer and surface layer. No matter which method is used for construction, it is necessary to avoid the key links that ensure that the cement mortar anti-corrosion layer does not have cracks and hollows. The "AWWAC.602B" specification for on-site construction of buried pipelines in the United States stipulates: Immediately seal all holes in the pipeline after spraying the inner village. After hardening, stop the damp maintenance and immediately pass water. Our company's practice has proved that , the maintenance work is negligent, and cracks will appear: Beijing City ×× project, when the pressure was applied, it was not sealed, and two longitudinal cracks of more than 2m long appeared on the top of the tunnel.
43.4, according to the test and research experience of Beijing Municipal Engineering Design and Research Institute for many years, when the crack width is less than 1 or 1.6m, it can be repaired under certain conditions: "Spherical cast iron bench centrifugal water mortar lining for small pipes (1$4179) stipulates that the maximum crack width is 1.6m. This specification is based on engineering practice experience, reference to domestic and foreign research results and the above international standards, and allows the crack width to be no more than 0.8runs
4.3.5 Oil and epoxy coal lead materials are widely used in China. External anti-separation coatings. Table 4.3.5-1 and Table 4.3.5-2 are formulated with reference to the "Specification for Construction and Acceptance of Buried Steel Pipeline Corrosion Protection (SY4020-88)" and the "Technical Standard for Buried Steel Pipeline Corrosion Protection" (SY128-87). The construction unit shall obtain the structural construction specified in the design: when the design is not specified, it shall be implemented in accordance with the provisions of Table 4.3.5-1 and 4.3.5-2. Whether it is constructed according to the design specifications or implemented according to the provisions of Tables 4.3.5-1 and 4.3.5-2, its quality acceptance standards shall comply with the provisions of Table 4.3.11.6. The surface of the outer anti-corrosion construction is damp and not clean: the surface is damp and clean, which affects the bonding and anti-corrosion effect. When the construction environment temperature exceeds the specified value, the oxygen-containing asphalt is not easy to solidify, and the oil-containing asphalt is difficult to apply. When the temperature is lower than the asphalt aging temperature, lifting and transportation may cause the anti-corrosion layer to break. When applying, the aging temperature specified in the "Green Point Test Method" (GB4510-84) should be followed to determine the timing of lifting and transportation. 4.3.7 The following practice shows that the No. 10 stone mortar meets the energy requirements of the outer anti-corrosion layer of the pipeline for conveying liquids with a medium temperature of less than 50°C. The water temperature conveyed by the water supply and drainage pipeline is generally below this temperature limit, so this system specification selects the No. 10 stone mortar as the material for the outer anti-corrosion tower of the pipeline. Glass cloth production process requires impregnation, and the wax-impregnated glass cloth is directly used in the outer anti-corrosion layer, which will affect the bonding effect of the outer layer. Therefore, this ship is determined to use de-waxed, non-waxed glass cloth. The commonly used film stripping method is to put the glass in an oven at high temperature for waxing before use. Medium-alkali glass cloth refers to glass with an alkali content of no less than 12%. When using oil-based back coating: According to the ambient temperature, the warp density of glass cloth is usually selected according to Table 4.1:
Selection of warp and weft density of glass cloth
With the working ambient temperature ()
25-·35
Glass cloth warp and weft density (base m)
12x 12
"Polyvinyl chloride industrial film that can withstand changes in ambient temperature" refers to the performance of being able to withstand temperatures as high as 70°C and as cold as -30°C. 49"Pre-painting Material Surface Inspection Standard"
(SYJ4007-86) stipulates that rust removal is divided into 2 levels: S2, S3, and S4. S refers to the use of power steel wire ropes to remove loose or warped oxide scales, loose rust scales, loose polyester layers and other debris on the steel surface: shot peening rust removal is divided into clean level (S1) and industrial level (S2). S2), near white grade (S2.5, white grade (S3). Near white grade (2.5) means that all scale, rust, coating and other contaminants are removed. After cleaning, there is almost no visible oil, grease, grease, hydrogenated scale, rust and coating on the steel surface. It is allowed to leave evenly distributed scale spots and rust on the surface, and the total area shall not exceed 5% of the total rust removal area. Article 4.3.9.3 of this article stipulates that the temperature of the raw material shall not exceed 250℃, and the curing time shall not exceed 5h , in order to avoid the occurrence of rusting when boiling asphalt. 4.3.9.4 stipulates that the coating temperature of lead asphalt shall not be lower than -188, in order to avoid the phenomenon of difficulty in coating due to too low temperature. 4.3.1 The anti-corrosion layer of epoxy coal asphalt is relatively thin. In accordance with 4.3.10.1 of this article, the welding surface shall be free of weld nodules, corners, smooth and smooth. In order to achieve this, in addition to careful operation of rust removal, epoxy glue shall be used to level the uneven parts. 4.3.11 The separation of steel pipes is mainly electrical In the chemical chamber, when the spark detector is checked, if there is a spark phenomenon, it means that the coating is not good and there is leakage. If it is not handled, electrochemical corrosion will occur in the future, affecting the life of the pipe. The spark in Table 4.3.11 is calculated from the "7850" (: corrosion layer thickness (mril): \: breakdown voltage (V)).
4.4 Installation of cast iron and ductile iron pipes
4.4.1 After the reform and opening up, our cast iron pipe production technology Development is rapid: the single gray cast pipe is developed into a ductile iron pipe with high strength, good toughness and corrosion resistance; the joint is also a single cotton cement closure, and the sliding ladder-shaped, T-shaped and flexible mechanical rubber gear-sealed interfaces are developed. In order to make it easier for adults, the current national cast iron, ductile iron pipe and pipe fittings standards are listed, see Table 4.2:
4.4.2 Cast iron pipe quality inspection, poor impact resistance, pipe joint structure has been shaped into many types, and the drop rate is as high as 5%. -10%. To judge whether there are fine cracks or cracks: You can use a soft plug or a small tool to tap the pipe body. The frequency of the sound can be used to judge whether the pipe body has fine cracks. The key symptom that affects the tightness of the pipeline is the smoothness of the external working surface and the internal working surface. Before the pipe joints and arm parts are grooved, the defects pointed out in this article must be carefully checked and removed before the sealing work of the joint installation can be carried out. Standard list
Sand doctor centrifugal
Cast iron pipe
Sexy connection
Gray rear swimming iron
Ladder lip rubber enclosure
Interface identification iron
Nanxin plan ball making
Hannuo iron pipe
Standard number: Interface form
GR3421—82
113422
663—86
G14-88||t t||CBI3295--91
Dongmen Shoutie Pipe State CB3420--82
Ball Zhao Lian Yin Pipe Companion GB13294-91
Yu Rubber Skin Shape
4.4.3 When installing the pipe, it is required to leave a longitudinal gap between the plugs. It is to select the temperature change during the installation to produce deformation. The rigid interface has a tolerance in the factory and the outer diameter of the plug end. The pipes are arranged in a combination and the circumferential direction is roughly the same. 4..+ When installing the active curve: the allowable angle of the flexible interface is determined by the relevant enterprise standards and the allowable angle of the interface outside the region. The relevant data are listed in Table 4.3. The allowable turning angle of the flexible interface is as follows:
Real National Note
People's Military
Shaped rubber garden
Slide:
Shaped rubber ring
Kubo iron camp
People's" riding machine
Replacement rubber ring
Wu concubine!
Note: [. American data tumor household ball network water replacement and its installation standard for dangerous parts (AWWA600 87);
2, Gan Benqiang material full white Japanese Kubo national ball belt cast iron kidney manual, the sex connection can be allowed in detail the turning angle, so after the turning angle, the gap of the interface can still ensure the thinnest (m) H into the gap for normal operation of the original right close, 4.4.5 this article 4.4.5, paragraph 2 rigid interface used for the right, some companies standard is to say that the leakage tree quality is not very accurate [Building Standard 5161) 4 grade asbestos, in recent years, my country has frequently issued the "warm and not wan (GB3701-87) national standard, in order to be consistent with the current national standard: this specification stipulates the use of machine selected 4 lower grade asbestos: this grade asbestos is close to the warm stone stick quality standard 3 (Building Standard 54-61) in the soft -4-Sichuan grade,
new and old standard stone grade fiber cone
distribution Comparison table
Name
Duo Yimo Cotton
(GB5701—87)
Yishi Pu Quality Standard
【Jianhuai 54—Xin]
Machine selection 4[-
Fiber length Screen bar
Soft--4-10
4.4. Jin Rigid joint "Waterline edge" refers to the triangular groove of the socket, the edge load near the inner end of the socket, see Figure 4.1 Waterline inner beam
Deep Kanghai
Figure 4.1, schematic diagram of the waterline of the socket
4.4.8 The temperature difference between day and night in the north is about 0--20℃. If the rigid joint is constructed at this temperature and no warming measures are taken, the phenomenon of one interface cracking every 5 pipe sections will occur. For example, this accident often occurs in the Baomai area. The interface construction should be carried out at a time when the temperature difference between the mouth and the night is low. In summer, it is better to work in the morning and evening, and in winter, it is better to work at noon, and cover and insulate.
4.4.1 At present, my country has introduced many cast iron pipe production lines. Some of these products are produced according to the S standard, and some are produced according to the national standard. The joints are various and the c
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