Some standard content:
National Standard of the People's Republic of China
Technical standard for water-supply well
Technical standard for water-supply well GB 50296-99
Editor: Former Ministry of Metallurgical Industry of the People's Republic of ChinaApproval department: Ministry of Construction of the People's Republic of ChinaEffective date: October 1, 1999
5-10-1
Notice on the release of the national standard
"Technical specification for water-supply well"||tt ||Construction Standard [1999]] No. 101
According to the requirements of the State Planning Commission's "1991 Engineering Construction Standard Formulation and Revision Plan" (Appendix 1 to Document No. 290 of the Planning and Development [1991]), the "Technical Specifications for Water Supply Pipe Wells" revised jointly by the former Ministry of Metallurgical Industry and relevant departments was reviewed and approved as a mandatory national standard by relevant departments, numbered GB50296-99, and implemented on October 1, 1999. The original national standard "Construction and Acceptance Specifications for Water Supply Pipe Wells" GBJ13-66 was abolished at the same time.
This specification is based on the requirements of the State Planning Commission's Document No. 290 [1991], edited by the former Ministry of Metallurgical Industry, and specifically composed of the Wuhan Survey and Research Institute of the Ministry of Metallurgical Industry, China Municipal Engineering Southwest Design Institute, China Coal Geology Bureau, Survey and Research Institute of the Ministry of Metallurgical Industry, Kunming Survey Institute of China Nonferrous Metals Industry Corporation and Hefei University of Technology. The revision team revised the original "Construction and Acceptance Specifications for Water Supply Pipe Well Engineering" GBJ13-~66. Since the specification has added the content of pipe and design, it was renamed "Technical Specifications for Water Supply Pipe Wells", approved by the Ministry of Construction on April 13, 1999 with Document No. 101 [1999], and jointly issued with the State Administration of Quality and Technical Supervision. During the revision process, the revision group conducted a large amount of investigation and research. In view of the problems found in the implementation of the original specification and the new requirements put forward in production, the revision group carefully summarized the practical experience of water supply pipe well design and construction in my country, and widely solicited opinions from relevant units and experts across the country. Finally, the former Ministry of Metallurgical Industry and relevant departments reviewed and finalized the draft. The main contents of this revision are: provisions on terms and symbols; added requirements for pipe well design; technical requirements for pipe well construction 510 2
This specification is managed by the State Metallurgical Industry Bureau, the Wuhan Survey and Exploration Research Institute of the Ministry of Metallurgical Industry is responsible for specific interpretation, and the Standard and Quota Research Institute of the Ministry of Construction organizes China Planning Press to publish and distribute it. Ministry of Construction of the People's Republic of China
April 13, 1999
Request, etc.
In the process of implementing this specification, it is hoped that all units will combine engineering practice and scientific research, carefully summarize experience, and pay attention to accumulating data. If you find any need for modification or supplement, please send your comments and relevant information to the National Standard Management Group of Technical Specifications for Water Supply Pipe Wells, Wuhan Survey and Research Institute, Ministry of Metallurgy, No. 177 Yejin Avenue, Wuhan City [Postal Code 430080, Fax (027) 86861906] for reference in future revisions. The main editor, participating editors and main drafters of this specification are as follows: Main editor: Wuhan Survey and Research Institute, Ministry of Metallurgical Industry Participating editors: China Municipal Engineering Southwest Design Institute China Coal Geology Bureau
Survey and Research Institute, Ministry of Metallurgical Industry
China Nonferrous Metals Industry Corporation Kunming Survey Institute
Hefei University of Technology
Main drafters: Hu Lian Zhang Xifan
: Ye Guijun Li Tiancheng
Jiang Benchang Qiu Zhangzhu
Terms and symbols
2.1 Terms
3 Design requirements
—General provisions
Well pipe layout and
Well body structure design
Filter design
Water output design review,
5—10—4
5-—10—4
—10—4
5—10-4
——10-4
5-10—5
5-10—5
-10—6
Construction requirements
General provisions
Drilling, wall protection and flushing media…．
Identification of lithology·
Well pipe installation·
Gravel filling and sealing outside the pipe……
5---10—6
—10—6
5—10—6
—107
5—107
5—10-7bzxz.net
Determination of well washing and water output………．
+.... 5-10—7
Water sample collection and inspection
Project acceptance
.5—10—7
.................... 510-8
Explanation of terms used in this specification.
5—10—8
5-—10- 3
Specification.
To unify the technical requirements for the design and construction of water supply pipe wells, this specification is specially formulated to apply to the design, construction and acceptance of domestic water and industrial production water pipe wells.
1.0.3 The design and construction of water supply pipe wells should be carried out after obtaining the hydrogeological data of the exploration stage specified in the current national standard "Water Supply Hydrogeological Exploration Specification" GBJ27. When the data cannot meet the design or construction of the pipe well, the hydrogeological exploration work equivalent to the exploration stage should be supplemented, or it should be carried out as an exploration and mining well. The exploration and mining should also comply with the provisions of the current national standard "Water Supply Hydrogeological Exploration Specification" GBJ 27 and this specification.
1.0.4 The materials used in water supply pipe wells should be products with factory certificates. If there is no factory certificate, they should be used only after being proved to be qualified by the inspection test. Domestic water supply pipes and related materials should use non-polluting and non-toxic materials. 1.0.5 Water supply pipes must be formally accepted before they can be put into use. 1.0.6 The design, construction and acceptance of water supply pipeline construction shall comply with the provisions of the relevant mandatory standards and specifications in force in China in addition to complying with this specification. 2 Terms and symbols
Exploration-production well
Exploration-production well
A water supply pipeline well that can meet the needs of obtaining hydrogeological data in water supply exploration 2.1.2 Drilling technology The general term for the process of forming a well during the construction of a well. 2.1.3 Well measurement
The process of detecting the depth and diameter of a well.
2.1.4 Well completion technology
Well completion technology
The general term for the processes of exploring a well, changing slurry, installing well pipes, filling gravel, sealing, as well as washing, pumping test, and collecting water samples.
2.1.5 Well structure
The general term for well diameter, well section, and well depth.
well diameter
diameter of well section
top-of-well diameter
2.1.7 wellbore diameter
diameter of well section.
2. 1,8 bottom-of-well diameterdiameter of well section at bottom end.
diamerer of pump installation section of2.1.9
diameter of well section where pumping equipment is installed.
2. 1. 10 diameter of water yielding section of well!diameter of well section where groundwater is taken
casing pipe
a non-porous pipe that supports and seals the well wall.
well casing
a general term for well casing pipes, filter pipes and sedimentation pipes. 2.1.13 Blank casing slump, a non-porous tube for depositing sand and sediment. 2.1.14 Flushing media, a material used to carry cuttings, clean the bottom of the well, cool and lubricate the drill and protect the well wall during drilling.
5—10—4
2.1.15 Screen assembly, located in the mining section, plays the role of filtering water, blocking sand and protecting the well wall. 2.1.16 Cage-type screen, a filter with a water inlet surface.
2.1.17 Screen pipe
Screen pipe
The skeleton pipe of wire-wound filter and gravel-filled filter. When used alone, it is also called filter.
Gravel pack
Granular particles with certain specifications filled in the annular gap between the filter pipe and the well wall, 2.1.19 Gravel-packed filter
Gravel-packed sereen
A filter with a certain specification of filter material filled around the filter pipe. Wire-wound screen
2.1.20 Wire-wound filter
A filter with a certain porosity by winding a certain specification of wire. 2.1.21 Effective porosity of screened well
The porosity that can be actually achieved when the filter pipe is installed in the mining section. 2. 1. 22 Well deflectionThe horizontal displacement of the actual axis of the well material from the vertical line. 2.1.23
The process of using different materials to prevent water from infiltrating outside the well. Maximum allowable entrance
velocity through well-wall
The maximum allowable entrance velocity through well-wall
The maximum allowable entrance velocity through well screens for groundwater to enter the well from the aquifer 2.1.25 Maximum allowable entrance
velocity through well screens The maximum allowable entrance velocity through well screens for groundwater to enter the well. 2.2 Characteristic
D, Outer diameter of filter pipe
D—Well diameter of mining section
K -- Permeability coefficient of aquifer
- Length of filter or filling section
-Effective pore-tunnel ratio of water inlet surface layer of filter pipe
Design of water outlet
Q. ——-Water inlet capacity of filter pipe
V ---Allowable water inlet flow rate of filter pipe
---Allowable water inlet flow rate of parallel wall
Design requirements
3. 1 General provisions
When designing pipe wells, the following main contents should be clarified3. 1. 1
Water usage, water demand (or number of wells) and water quality requirements; the scope of the proposed well area;
water supply design intention and construction progress;
other requirements of users, etc.,
survey. Before designing pipe wells, relevant information of the well construction area should be collected, and on-site pipe design should be carried out. The design should be carried out according to the water demand, water quality requirements and the geological and hydrogeological conditions of the well construction area. The following requirements should be met: The well group distribution in the main water-using area should be reasonable, the average well disturbance coefficient should be 25%~~30%, and the wells should maintain a sufficient safety distance from the buildings (structures). When designing the well group, spare pipes should be reserved. The number of spare pipes should be set according to 10%~20% of the design 3.1.4
water, and shall not be less than ~. When designing the well group, a long-term observation network should be arranged according to the hydrogeological conditions and water demand of the well construction area and the water quality requirements of 3.1.5
to monitor the dynamics of groundwater exploitation. The layout of the groundwater long-term observation network and the design of the long-term observation holes should comply with the provisions of the current national standard "Water Supply Hydrogeological Survey Specification" GBJ27. 3.1.6 Pipe and pipe structure design should include the following contents: wellbore structure, pipe and pipe configuration and pipe material selection; gravel filling position and filter material specifications; closure position and materials; well ancillary facilities. The design of pipe and pipe diameter should include the following contents: opening and well diameter: number of well sections and diameter change; pump installation section diameter: mining section diameter: final well diameter. For existing pipe and pipe wells that do not meet the design requirements or are not applicable, a backfill or treatment plan should be proposed.
3.2 Pipe parallel layout
3.2.1 In alluvial and flood plain areas, well groups should be arranged in equal distances or in a plum blossom shape perpendicular to the direction of groundwater flow. When there is an ancient riverbed, they should be arranged along the ancient riverbed. 3.2.2 In large alluvial and flood fan areas, when groundwater extraction is close to natural recharge, well groups should be arranged in a horizontal row or fan shape perpendicular to the direction of groundwater flow. When groundwater extraction is less than natural recharge, well groups should be arranged in an arc shape. When extraction and storage are slow and used for regulation, well groups should be arranged in a grid-like manner.
3.2.3 In riverside areas, well groups should be arranged in single or double rows parallel to the river. 3.2.4 In areas with thick aquifers or multiple aquifers and sufficient groundwater recharge, water well groups can be arranged in sections or layers.
3.2.5 In intermittent river valley areas, well groups should be arranged in areas with thick aquifers. 3.2.6 In clastic rock areas, the group should be arranged according to the water storage structure and geomorphic conditions, and should meet the following requirements: 1. The water-rich section of the intrusion contact zone can be arranged along this zone; 2. The water-rich section of the fracture zone or the anticline axis can be arranged in a linear shape; 3. The homogeneous aquifer can be arranged in a grid, plum blossom or arc shape. In carbonate rock areas, well groups should be arranged according to water storage structures and geomorphic conditions, and should meet the following requirements:
The high-water section of the syncline structural basin should be arranged along the syncline axis; the water-rich section of the axis of the inclined anticline should be arranged along the anticline axis; the deep water-rich section of the monocline structure should be arranged perpendicular to the direction of groundwater flow in the runoff or discharge area;
The water-rich section of the fault and fracture zone should be arranged along the zone. When the karst river valley is the discharge base level of the karst aquifer, it should be arranged on the shore. 6 When carbonate rocks and non-carbonate rocks are in contact with high water, they should be arranged on the carbonate rock side.
3.2.8 In igneous rock areas, well groups should be arranged according to their distribution and the degree of fissure gland development, and should meet the following requirements.
Weathering fissures should be arranged in water-rich sections according to the topography; structural fissures should be arranged in high-water sections according to the structural location. 2
3.3 Well body structure design
The well body structure should be designed according to the formation conditions, groundwater depth and drilling technology, and should be carried out in the following steps:
Determine the well diameter of the mining section and the pump installation section according to the well completion requirements; determine the well section diameter change and corresponding length according to the formation and drilling method; 2
Determine the opening diameter of the well according to the need for non-segment diameter change. 3
3.3.2 The diameter of the mining section should be determined comprehensively based on the factors such as the designed water plate of the pipe well, the allowable water inflow velocity of the well wall, the depth of the aquifer, the length of the mining section, the type of filter and the drilling technology.
3.3.3 The inner diameter of the pump section should be determined according to the needs of the designed water base and the dynamic water level measuring instrument, and should be 50rntm larger than the minimum inner diameter of the well pipe calibrated by the selected pumping equipment.
3.3.4 The diameter of the mining section of the non-gravel filter pipe well in the loose layer area should be 50mm larger than the outer diameter of the designed filter.
3.3.5 The depth design of the pipe well should be determined comprehensively based on the buried depth, thickness, water quality, water richness and water output capacity of the aquifer (group, section) to be mined. 3.3.6 The length of the sedimentation pipe should be determined according to the lithology of the aquifer and the well depth, and should be 2 ~ 10m. The well body structure design of the pipe well in bedrock areas should comply with the following provisions: When there is an overburden or unstable rock layer on the upper part, a measuring well wall pipe should be installed. When the rock layer in the lower mining section is broken, a filter should be installed. When water is taken from the overburden layer at the same time, the pipe well design of the overburden layer section should be carried out according to the requirements of the loose layer pipe. The pump section should be equipped with a measuring well pipe; the length, number and diameter change position of the well section should be determined according to the rock layer conditions, formation technology and drilling method.
The diameter of the mining section of the pipe well without filter in bedrock area shall be determined according to the high water content of the aquifer and the designed water output, and shall not be less than 130mm. 3. 3. 9
The design of the closed position of the pipe well in the loose layer area shall comply with the following provisions: the periphery of the wellhead shall be closed;
The periphery of the well pipe in the aquifer with poor water quality or non-exploitable aquifer shall be closed. 3.3.10 The design of the closed position of the pipe well in bedrock area shall comply with the following provisions: when the overburden layer does not take water, the periphery of the pipe shall be closed; when taking water from the overburden layer, it shall be implemented in accordance with the provisions of Article 3.3.9 of this Code. The bottom of the well pipe in the overburden layer and the fixed rock layer should be sealed; the overlapping parts between the diameter change of the well pipe in the non-exploited aquifer should be sealed; the aquifer with poor water quality (or the upper polluted aquifer) and the exploited aquifer should be sealed. The design of the pipe should have holes for measuring the water level and should prevent the entry of debris. The pipe material should be determined based on the purpose of water, groundwater quality, well depth, pipe strength, pollution-free and economic rationality. 3.4 Filter design
Filter type should be selected according to the properties of the aquifer according to Table 3.4.1. Selection of filter type
Table 3.4.1
Aquifer membrane
If the aquifer is not fixed
Fissured soil, filled
Cystic soil, no filled area
Gravel soil
Sand soil
dto<2mm
d20≥2mm
Coarse soil, medium soil
Fine sand, silt sand
Filter type
(Not a cystic filter)
Skeleton (or tumor wire) filter, wire humidifier, carbon filled filter group, bone channel (with pure) filter (no filter group installed), urea filled filter, continuous filter, skeleton (or shrink wire) filter, domain alcohol filter, wire filled filter, double waist filled filter group, filled filter group, the selection of filter manufacturing materials should be determined according to groundwater quality, stress conditions and 3.4.2 economic rationality and other factors.
When groundwater is corrosive or prone to scaling, the design of the filter (tube) shall meet the following requirements:
It shall be made of corrosion-resistant materials. When materials with poor corrosion resistance are used, anti-corrosion treatment shall be performed;
2. When the particle composition of the aquifer is coarse, a kidney frame filter shall be used; 3. The wire winding material of the wire winding filter shall be stainless steel wire, steel wire or reinforced polyethylene water filter wire.
510—5
3.4.4 When designing filters in homogeneous aquifers, their length shall comply with the following provisions: When the thickness of the aquifer is less than 30m, the thickness of the aquifer or the thickness of the aquifer below the design dynamic water level shall be taken;
2 When the thickness of the aquifer is greater than 30m, it shall be determined based on the water separation property of the aquifer and the design water yield;
Filters in heterogeneous aquifers shall be installed in the main aquifer and their length shall comply with the following provisions:
For county-shaped heterogeneous aquifers, the cumulative length of the filter shall be 30m; For fractured and soluble aquifers, the cumulative length of the filter shall be 30~50m. 3. 4. 6 When designing the diameter of the filter tube, it shall be determined based on the design water yield, filter tube length, filter tube surface porosity and allowable filter tube inlet flow rate. The design of the wire-wrapped filter shall comply with the following provisions: 3.4.7
The perforation shape, size and arrangement of the skeleton tube shall be determined according to the strength of the tube and the processing technology. The porosity should be 15%~~30%. There should be longitudinal ribs on the skeleton tube. The rib height should be 6~8mm. The spacing between the ribs should ensure that the wire is 2~4mm away from the tube wall. Hoops should be provided at both ends of the ribs. The wire-wrapped material should be non-toxic, corrosion-resistant, with high tensile strength and low expansion coefficient. The cross-sectional shape of the wire should be trapezoidal or triangular. The wire should not be loose. The allowable deviation of the wire spacing is ±20% of the design wire spacing. 3. 4. 8
The hole size of the wire-wrapped filter shall be determined according to the particle composition and uniformity of the aquifer and shall comply with the following provisions:
For gravel soil aquifers, d20# shall be used.
2For sandy soil aquifers, dsot
4z shall be used as the maximum effective diameter when the sieve weight of the sampled particles in the gravel soil aquifer is 20%.
The maximum effective diameter of
2 dsb It is the maximum particle diameter when the sieve weight is 50% in the water-containing particles of sandy soil.
3.4.9 The design of the wire mesh surface density of the wire mesh filter should be determined by the following formula: (1-4)
Wherein - wire mesh surface density
-pad width or diameter (mm):
pad center distance (mm)
d: - wire mesh diameter or width (mm);
center distance of the wire mesh (mm).
3. 4. 10 The filter media specifications of gravel-filled filters can be determined according to the following provisions: 1 Sandy soil aquifer:
Dsa = (5~8)dso
2 Gravel soil aquifer, when dza<2mm, Dso - (6~8)d20
(3.4.10-1)
(3.4.10-2)
3 Gravel soil aquifer, when dzo≥2mm, no gravel filling or filling with 10~20mtm of filler is required;
The uniformity coefficient of the filter media should be less than 2.
Note: 1 When the coefficient of uneven particle size in the coarse sand layer in the sandy soil is greater than 10, some of the samples should be removed and recalculated until the coefficient of uneven particle size is less than 10. Take its LDso and substitute it into the formula (3. . 10-1) to determine the sugar material specifications:
2 ± Dsb is the maximum particle diameter when the sieve weight is 50% in the sampled particle group or the sampled particle group.
The size of the gravel filter frame pipe seam should be D10. 3.4.11
Note: D1α is the maximum apparent diameter when the sieve weight is 10% in the aggregate sieved sample particle composition,
. The thickness and height of the filter media of the gravel-filled filter should meet the following requirements: 3. 4. 12
The filter media thickness should be determined according to the lithology of the aquifer, preferably 75-150mms2 The bleeding height should exceed the upper end of the filter tube. 3, 4. 13 When designing the flow material specifications in heterogeneous aquifers or multi-layer aquifers, the following requirements should be met:
1 When filling in layers, the filter frame tube wire mesh gland size and filter media specifications should be designed in layers, and the filling height of the filter media should exceed the top plate and bottom plate of the fine-grained aquifer; 2 When there is no need to fill gravel in layers, it should all be carried out according to the requirements of the fine-grained aquifer. 3. 4.14 The filter material specifications of double-layer gravel filter shall meet the following requirements: 5—10-6
The outer filter material shall comply with Article 3.4.10 of this Code; the inner filter material shall be 4 to 6 times the outer filter material specifications; 3 The friction of the filter material shall be 75~100mm for the outer layer and 30~50mm for the inner layer; the inner filter material mesh cage shall be equipped with a protective device.
3. 5 Water output design review
The total water output designed for the pipe well group shall be less than the groundwater allowable mining area in the mining area.
The designed water output of the pipe well shall be less than the water inlet capacity of the filter pipe. 3.5.2
The water inlet capacity of the filter tube should be determined by the following formula:
Q,--+n·V,.D,·L
Water inlet capacity of the filter tube (m/s);
Effective porosity of the water inlet surface layer of the filter tube, which should be calculated as 50% of the porosity of the surface layer of the filter tube;
Allowable water inlet flow rate of the filter tube (m/s), which shall not be greater than 0.03m/s; -Outer diameter of the filter tube (m);
Effective water inlet length of the filter tube (m), which should be calculated as 85% of the length of the filter tube.
The designed water outlet plate of loose layer pipe wells shall comply with the provisions of 3.5.3
of Article 3.5.2 of this Code, and the allowable well inlet flow rate shall be checked by the following formula: v
Designed water outlet (m/s);
De——-mining section diameter (m);
Filter length (m),
V,——-allowable well wall inlet flow rate (m/s). 3.5.4
The allowable well wall inlet flow rate should be calculated according to the following formula: Vj=VK/15
KPermeability coefficient of aquifer (m/s).
When the groundwater is corrosive and easy to scale, the allowable filter pipe inlet flow rate in Article 3.5.2 of this Code shall be determined by reducing it by 1/3~1/2. 4.1.1 Before construction, a site survey should be conducted to understand the construction conditions, groundwater exploitation conditions, etc.
4.1, 2 After a brief site survey, a pipe and well construction organization design should be prepared. The construction organization design should include the following contents:
1 Project tasks and requirements,
Construction technical measures:
Main equipment, personnel, materials, costs and construction progress. 3
4.2 Drilling, protection and flushing media
4.2.1 The drilling equipment and technology used in the pipe well construction should be selected according to factors such as stratum lithology, hydrogeological conditions and well structure. 4.2.2 During the drilling of loose layers, when it is difficult to drill due to rock and block, internal blasting can be carried out. Blasting design should be carried out before blasting, and the safety of ground buildings should be ensured. 4.2.3 The parallel body should be round and vertical, and should meet the following requirements: The parallel body diameter shall not be less than the designed parallel diameter
2 less than or equal to 100m parallel section,The deflection of the top angle shall not exceed 1°; for the section greater than 100m, the rate of increase of the top angle storage material per 100m shall not exceed 1.5°. There shall be no sudden changes in the top angle and azimuth of the section.
The amount of protective pipes should be guaranteed not to loosen during the construction of the pipe joint, and the joint mouth should not be 4.2.4
The wall protection method for drilling should be determined according to the lithology of the formation, the drilling method and the water conditions for construction.
4.2.6 The flushing medium should be selected according to the lithology of the formation, the drilling method and the construction conditions, such as clean water, slurry, air or foam, and should meet the following requirements: 1 Ensure the stability of the joint wall
Reducing the impact on the permeability and water quality of the aquifer; 2
3 Improving the drilling efficiency, etc.
The various performance indicators of the flushing medium should meet the requirements of relevant regulations. During the drilling process, various performance indicators should be measured regularly. 4.3 Lithology classification The classification of strata in the well should be determined based on the data of water wells and comprehensive analysis of drilling cuttings. When there is no water well data, soil and rock samples should be taken according to the following provisions. In the loose layer area, a soil sample should be taken from the aquifer. In the bedrock area, it should be determined based on the core or the reflected rock powder. 4.3.2 The determination of the name of the loose layer soil should comply with the provisions of Table 4.3.2. Table 4.3.2 Name of loose contact layer soil
Mainly round and sub-shaped, particles with a diameter greater than 200 mm account for more than 50% of the total weight Mainly angular, particles with a diameter greater than 200 mm account for more than 50% of the total weight Block
Mainly shaped and sub-shaped, particles with a diameter greater than 20 mm account for more than 50% of the total weight Mainly spherical, particles with a diameter greater than 20 mm account for more than 50% of the total weight Mainly shaped and sub-circular, particles with a diameter greater than 2 mm account for more than 50% of the total weight Mainly angular, particles with a diameter greater than 2 mm account for more than 50% of the total weight Particles with a diameter greater than 2 mm account for 25%~50% of the total weight Particles with a diameter greater than 0.5 mm account for more than 50% of the total weight Particles with a diameter greater than 0.25 mm account for more than 50% of the total weight.0.075mm The particles with a particle size larger than
do not exceed 85% of the total weight. The particles with a particle size larger than 0.075mm do not exceed 50% of the total weight. The index of hardness 110
Plasticity index 10≤17
Powder spray cement
±Austenitic index Tp>17
Note: When naming, the grain should be grouped from large to small according to the particle size, and the first to meet the requirements will be determined. 4.3.3 The sampling of soil and rock samples from exploration and mining wells shall be carried out in accordance with the relevant provisions of the current national standard "Specifications for Hydrogeological Exploration for Water Supply" GBJ 27-88. 4.3.4 The soil and rock samples taken during the construction of the pipeline shall be properly preserved. 4. 4 Well pipe installation
Before installing the well pipe, the following preparations should be made:4.4.1
Carry out pipe arrangement according to the well pipe structure design;2Inspect the quality of the pipe and it should meet the requirements;Before lowering the pipe, a well exploration should be carried out;
4For wells with mud wall protection, the mud should be appropriately diluted and the thick mud at the bottom of the well should be removed.4.4.2The pipe lowering method should be selected based on factors such as pipe strength, lowering depth and lifting equipment capacity, and should meet the following requirements!1The lifting pipe lowering method is suitable for well pipes with a deadweight (or floating weight) less than the allowable tensile strength and lifting safety load of the well pipe
2The tray (or floating plate) pipe lowering method is suitable for well pipes with a deadweight (or floating weight) exceeding the allowable tensile strength and lifting safety load of the well pipe.3The multi-stage pipe lowering method is suitable for well pipes with complex structures and excessive lowering depths. 4.4.3 When the well pipe is placed below, the well pipe must stand upright at the center of the wellhead, and the upper end should be kept horizontal. The deflection of the well pipe should meet the requirements of Article 4.2.3 of this specification. The allowable deviation of the filter installation depth should be ±300mm.
4.4.4 The sedimentation pipe should be sealed at the bottom. When the lower part of the loose layer has been drilled and is not used, the well pipe should be firmly located to prevent sinking; the well pipe of the bedrock well pipe should be located on the variable diameter well platform of the stable rock layer.
4.4.5 For the well pipe with filling filter, a center finder should be set. 4.5 Gravel filling and pipe outside sealing
4. 5.1 For the well pipe with gravel filling filter below, filling and grinding should be carried out in time after the well pipe is installed. Before filling gravel, the following preparations should be made:
1 The mud in the well should be diluted (except for high-pressure aquifers); 2 Prepare the filter material according to the design requirements, and its quantity should be determined by the following formula: V-0. 785(D*--D,*)L - α
Number of filter media (m\),
wherein V
Dr-diameter of gravel filling section (m),
D,--—outer diameter of filter pipe (m),
length of gravel filling section (m),
excess diameter coefficient, generally 1.2～1.5.
The quality of filter media should meet the following requirements!
Filter media should be sampled and screened, and the number of discs that do not meet the specifications shall not exceed 15% of the designed quantity,
The roundness of the particles is better, and it is strictly forbidden to use angular crushed stones; it should not contain soil and debris;
Silica gravel is used as filter media.
The gravel filling method should be determined based on factors such as well wall stability, flushing medium type and pipe well structure.
4. 5. 4 When filling, the filter material should be filled evenly and continuously along the four sides of the well pipe, and measured as it is filled. When it is found that the filling quantity and depth are greatly different from the calculation, the cause should be found and eliminated in time. 4.5.5 For pipe wells using double-layer gravel-filled filters, the inner filter material should be filled first according to the design specifications. The gravel filling method of the outer filter material is the same as that of the single-layer gravel-filled filter. 4.5.6 When the outer ring of the parallel pipe is sealed with clay, high-quality clay should be used in the shape of balls (blocks), the size of which should be 20~30mm, and it should be filled slowly in a semi-dry (hard plastic or plastic) state. 4.5.7 When the outer ring of the parallel pipe is sealed with cement, the performance indicators of the cement and the sealing method should be determined based on factors such as the lithology of the formation, the quality of groundwater, the pipe well structure and the drilling method. 4.5. 8 The periphery of the wellhead pipe should be sealed.
4.5.9 After the well pipe is sealed, the effect should be checked. If it does not meet the requirements, it should be sealed again.
4.6 Well washing and determination of water output
4.6.1 Well washing must be carried out in time.
4.6.2 The washing method should be selected according to the characteristics of the aquifer, the pipe structure and the pipe strength, and two or more washing methods should be used in combination.
4.6.3 When the pipe strength of the loose layer allows, it is advisable to use piston and compressed air to wash the well.
4.6.4 For pipes with slurry wall protection, when the mud skin on the wall is difficult to remove, it is advisable to use chemical washing and other washing methods in combination.
For pipe wells in carbonate rock areas, liquid carbon dioxide combined with sodium hexaphosphate or hydrochloric acid should be used for washing.
4.6.6 Pipes and wells in clastic rock and igneous rock areas should be washed by piston, air compressor or liquid carbon dioxide.
4.6.7 The inspection of the washing effect should meet the following requirements: the water output should be close to the design requirements or the difference between two consecutive unit water outputs should be less than 1
10%, and the sand content of the water should meet the requirements of Article 4.6.11 of this Code. 2
4.6.8 After the well washing is completed, the sediment in the well should be fished out and a pumping test should be carried out. The number of descents in the pumping test should be once, and the water output should not be less than the designed water output of the pipe.
4.6.9
4.6.10 The water level and water output of the pumping test should be observed continuously, and the stable duration is 6~8h. The water output and dynamic water level of the pipe should be determined according to the stable value. 4.6.11 Before the end of the pumping test, the sand content of the pumped water should be measured. The sand content of the water discharged should be less than 1/200000 (volume ratio). 4.7 Water sample collection and inspection
4.7.1 Before the end of the pumping test, water samples should be collected for inspection according to the purpose of the water or design requirements.
4.7.2 The container for collecting water samples should meet the following requirements 1 The container should be a hard glass bottle or a polyethylene bottle, 5-10-7
The container must be clean. When sampling, rinse it three times with sampling water. 2
4.7.3 Water samples should be collected at the outlet of the pumping equipment. The collection quantity should be 2~3L. The number of trays for collecting water samples for special projects shall comply with relevant regulations. 4.7.43 The water sample containers used for bacteria testing must be sterilized, and the water samples should be protected from contamination during collection, transportation and storage. 4.7.5 After the water samples are collected, they should be labeled and placed in a cool place, and sent for inspection in a timely manner. Water samples that need to be added with preservatives should comply with relevant regulations. 5 Project Acceptance
Water supply pipe well projects should be accepted in accordance with this specification. 5.0.2 The acceptance of pipe wells should be carried out on site,And it shall meet the following quality standards, the water volume shall basically meet the designed water volume;
The sand content of the water shall meet the requirements of Article 4.6.11 of this Code, 2
The slope of the water shall meet the requirements of Article 4.2.3 of this Code; 3
The height of the sediment in the water shall be less than 5% of the depth of the water. 4
5. 0.3 After the acceptance of the water supply pipe well is completed, the acceptance form of the water supply pipe well shall be filled in. 5.0.4 The water supply pipe well project report shall include the following contents: 5-~ J0--8
1 Text description,
2 Drawings and materials (including the schematic diagram of the plane position of the pipe well, the comprehensive columnar diagram of the pipe well, soil or rock sample data, pumping test data and water quality inspection data, etc.), 3 Appendix (including the acceptance form of the pipe well, etc.).
Explanation of terms used in this specification
1. In order to facilitate the distinction in the implementation of the provisions of this specification, the terms with different degrees of strictness are explained as follows:
(1) Terms that indicate that it is very strict and must be done: positive terms use "must" and negative terms use "strictly prohibited"; (2) Terms that indicate that it is strict and should be done under normal circumstances: positive terms use "should" and negative terms use "should not" or "must not"; (3) Terms that indicate that there is a slight choice and should be done temporarily when conditions permit: positive terms use "should" and negative terms use "should not"; terms that indicate that there is a choice and it can be done under certain conditions use "may". 2. When the specification specifies that it should be implemented in accordance with other relevant standards or specifications, the wording should be "should comply with the provisions" or "should be implemented in accordance with".
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