Construction method of large-diameter water intake well

Abstract

The invention discloses a large-diameter water intake well construction method, and belongs to the technical field of underground water intake engineering construction. In order to solve the problems of high formwork erecting risk, poor filter element mounting reliability and the like in a traditional process, the method comprises the steps that an underground well wall is poured, a top beam is widened, 16 # channel steel (the interval is 900 mm) is laid on a cross-shaped supporting beam to form a horizontal bearing system, and a disc buckle type frame body supporting formwork with the height smaller than or equal to 5 m is erected; a hole is drilled behind a water inlet of the underground well wall to install a double-layer inverted filter element (the double-layer inverted filter element is fixed by gravel with the particle size of 10-20 mm and a galvanized wire mesh with the particle size of 50-80 mm), and a finished filter element sleeve is embedded in the overground well wall and is pre-filled with an inverted filter. Through structural stress system conversion, the formwork erecting height is reduced to 5 m from 13.53 m, and the super-danger large risk is reduced; the differential filter element technology enables the positioning error to be less than or equal to 5mm, and the reverse filtration efficiency is improved to 95% or above. The construction is safe and controllable, the quality is reliable, the construction period is shortened by 30%, the comprehensive cost is reduced by 25%, and the method is suitable for large-diameter water intake well construction of water supply projects such as municipal administration and railways.

Description

Technical Field

[0001] The invention relates to the technical field of underground water extraction engineering construction, in particular to a large-diameter water extraction well construction method. Background Art

[0002] (1) Current status of existing technologies Traditional large-diameter water well construction primarily uses a ground-based formwork process. The core process is: erecting a full-height frame at the bottom of the well → supporting the well wall and manhole cover formwork → pouring concrete → dismantling the frame. This process relies on the following technical means: Formwork support: wooden formwork or combined steel formwork is used, and is directly supported from the bottom of the well to the wellhead through a φ48 steel pipe frame (the formwork height is often 10-15m), with the frame uprights spaced 1.2-1.5m apart, and lacks a horizontal load-bearing transfer structure.

[0003] Filter element installation: Pre-buried filter elements are used in both underground and above-ground well walls. The filter elements are filled with gravel of a single particle size and fixed to the steel mesh by wire tying.

[0004] (2) Deficiencies in existing technologies Formwork safety and quality issues: High formwork risks: Frames over 10m high are considered extremely dangerous and require expert review. The frame's own weight accounts for 30% of the total load, and it is prone to overturning due to bottom foundation settlement or top load concentration (a domestic project once experienced an overall frame collapse accident, resulting in 5 casualties).

[0005] Formwork deformation: The wooden formwork of large-span manhole covers (such as 10.4m diameter) is not rigid enough. The center deflection after pouring can reach more than 50mm, causing the manhole cover to crack and leak, and the cost of subsequent repairs will increase by 15%-20%.

[0006] Filter element failure mechanism: Defects of underground pre-embedding: When pre-embedding filter elements in the water inlet holes of underground well walls, the downpipe (diameter 200-250mm) used for pouring concrete is prone to collision with the filter elements, resulting in a 40% probability of displacement exceeding 30mm. At the same time, underground mud and sand accumulate during the drilling process, clogging the filter element porosity by more than 50%.

[0007] Disadvantages of pre-buried filter elements on the ground: Pre-buried filter elements on the ground well wall require holes to be drilled in the template, and the positioning error is often as high as 10-15mm. In addition, the single particle size filter layer (such as 50-80mm gravel) has a retention rate of only 60% for fine-grained sediment, resulting in the siltation period of the water inlet being shortened to 3-6 months, requiring frequent silt removal.

[0008] Construction efficiency bottleneck: The traditional process requires that the frame be erected only after the concrete strength of the cross-support beam reaches 100% (approximately 28 days). To address the technical bottlenecks of the traditional process, namely "high formwork risk - poor filter element reliability - lengthy procedures", a large-diameter water well construction method is required. By using the cross-beam bottom return top process, construction can be started in advance when the strength reaches 75% (approximately 14 days), thus shortening the construction period of the key line by 14 days. Summary of the Invention

[0009] The purpose of the present invention is to provide a large-diameter water well construction method, which achieves a technological breakthrough through the following core innovations: Conversion of spatial force system: The traditional "single support of ground-based frame" is changed to a three-dimensional load-bearing system of "widened crown beam + channel steel + disc-shaped frame". The main load is borne by the horizontal structure (cross beam, crown beam), and the vertical formwork height is reduced from 13.53m to 5m, thus achieving a dimensional reduction in the formwork risk level.

[0010] Environmentally adaptable filter element technology: In view of the differences between underground "complex geology + limited space" and above-ground "controlled environment + open space", differentiated processes of "underground post-drilling + double-layer filtration" and "above-ground embedded casing + pre-filled filtration" are designed to solve the filter element installation problems in different environments.

[0011] Collaborative process optimization: By utilizing the cross-beam top-return technology and the fast erection characteristics of the buckle frame, the parallel operation of "underground structure construction - frame erection - above-ground structure construction" is realized, shortening the total construction period by more than 30%.

[0012] The present invention is achieved through the following technical solutions: A large-diameter water well construction method comprises the following steps: Step S1: pouring the underground well wall, ring beam and widened crown beam, wherein the widened crown beam extends into the well to form a frame support platform; Step S2: laying load-bearing components on the cross support beam, wherein the load-bearing components are fixedly connected to the widened crown beam; Step S3: Building a frame based on the load-bearing components to support the large manhole cover template and the above-ground manhole wall template; Step S4: The filter element is installed at the underground well wall water inlet by post-drilling, and the filter element casing is pre-buried at the above-ground well wall water inlet.

[0013] As a further improvement to the technical solution of the present invention, the widened crown beam extends into the well with a width of 200-300 mm, and forms a horizontal load-bearing system with the cross support beam.

[0014] As a further improvement to the technical solution of the present invention, the load-bearing member is 16# channel steel, which is laid on the cross support beam at a spacing of 900mm, and the ends are welded and fixed to the embedded steel plates of the widened crown beam, with the weld height ≥8mm.

[0015] As a further improvement of the technical solution of the present invention, the frame is a disc-type frame, with an erection height of ≤5m, a vertical distance × a horizontal distance of the vertical poles of ≤900mm×900mm, and a step distance of ≤1500mm.

[0016] As a further improvement to the technical solution of the present invention, the disc-shaped frame is provided with an oblique brace, and the oblique brace is provided every three spans along the longitudinal direction, with an angle of 45°-60° with the horizontal plane.

[0017] As a further improvement of the technical solution of the present invention, the filter element installed by drilling a hole in the underground well wall includes a double-layer filter layer, the inner layer is gravel with a particle size of 10-20mm, and the outer layer is gravel with a particle size of 50-80mm. The thickness of each layer is 1 / 2 of the well wall thickness.

[0018] As a further improvement to the technical solution of the present invention, the outer layer of the filter element is wrapped with 20-mesh galvanized wire mesh, fixed to the well wall by M12 bolts at a spacing of 300mm, and the bolt holes are sealed with epoxy resin.

[0019] As a further improvement of the technical solution of the present invention, the above-ground well wall filter casing is fixed to the well wall steel bars by welding with Φ12 steel bars, with a positioning deviation of ≤3mm, and the casing is pre-filled with a crushed stone filter layer with a particle size of 10-20mm.

[0020] As a further improvement to the technical solution of the present invention, the above-ground well wall is cast in sections along the height direction, with each section casting height ≤3m, and the upper layer is cast after the lower layer concrete strength is ≥75% of the design value.

[0021] As a further improvement to the technical solution of the present invention, the frame is connected to the ground well wall template through cross bar supports, and the spacing between the cross bar supports is ≤1200mm, forming a rigid connection system.

[0022] In summary, the beneficial effects of the present invention are as follows: (1) Improved safety performance Formwork risk level reduction: Formwork height is reduced from 13.53m to 5m. Frame erection is classified as a "highly dangerous sub-project" (not super-dangerous), and no expert review is required, reducing safety management costs by 40%.

[0023] Enhanced anti-overturning ability: Through the horizontal load-bearing system of channel steel and diagonal bracing, the anti-overturning coefficient of the frame is increased from 1.1 of the traditional process to 1.8, meeting the requirements of the "Uniform Standard for Safety Technology of Construction Scaffolding" GB51210.

[0024] (2) Breakthrough in quality control Template forming accuracy: The rigidity of the buckle frame is 60% higher than that of the traditional steel pipe frame, the center deflection of the manhole cover template is ≤15mm (50mm for traditional process), and the concrete surface flatness is ≤5mm (10mm for traditional process), meeting the standard of fair-faced concrete.

[0025] The filter element is long-lasting and reliable: the underground filter element has a filtration efficiency of 96% (70% for traditional processes), the above-ground filter element has a positioning error of 3mm (10mm for traditional processes), the water inlet sedimentation period is extended to 12-18 months, and maintenance costs are reduced by 60%.

[0026] (3) Significant economic benefits The cost of erecting the frame has been reduced from 85 yuan / m³ to 58 yuan / m³, a decrease of 31.8%; The construction period was shortened from 80 days to 55 days, a reduction of 25 days (a decrease of 31.25%); The cost of handling quality defects was reduced from 120,000 yuan to 24,000 yuan, a reduction of 80%.

[0027] (IV) Environmental benefits It reduces the amount of high-altitude work by 60% and construction dust by 30% (the dust generated by the assembly of the screw-type frame is less than that of the traditional steel pipe frame), meeting the requirements of the green construction guidelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings: Figure 1 This is a cross-sectional view of the overall construction of a water intake well according to an embodiment of the present invention; The underground shaft wall (600mm thick), widened crown beam (width = original crown beam + 300mm), 16# channel steel (900mm spacing) and 5m high plate-and-hook frame are shown, compared with the traditional 13.53m support formwork height.

[0029] Figure 2 A detailed diagram of the connection node between the channel steel and the crown beam according to an embodiment of the present invention; Mark the embedded steel plate (50×50×8mm), U-shaped clamp (∠50×5), and welding seam (height 8mm) to show the horizontal load transfer path.

[0030] Figure 3This is a cross-sectional view of an underground well wall filter element installation according to an embodiment of the present invention; Shown are the drilling diameter (filter element outer diameter + 20mm), double-layer filter (particle sizes 10-20mm and 50-80mm), galvanized wire mesh (20 mesh), and M12 bolts (300mm spacing) for fixing.

[0031] Figure 4 This is a pre-buried node diagram of the filter element casing on the above-ground well wall according to an embodiment of the present invention; It shows the PVC-U casing (DN300) and Φ12 steel bar welded and fixed (weld length 5d), pre-filled gravel filter layer and gauze sealing structure.

[0032] Figure 5 The figure is a schematic diagram of the framework of a large-diameter water well construction method of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, features, and advantages of this application more obvious and easy to understand, the technical solutions in the embodiments of this application are clearly and completely described. Obviously, the embodiments described below are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0034] Reference Figure 5 A large diameter water well construction method comprises the following steps: Step S1: pouring the underground well wall, ring beam and widened crown beam, wherein the widened crown beam extends into the well to form a frame support platform; Step S2: laying load-bearing components on the cross support beam, wherein the load-bearing components are fixedly connected to the widened crown beam; Step S3: Building a frame based on the load-bearing components to support the large manhole cover template and the above-ground manhole wall template; Step S4: The filter element is installed at the underground well wall water inlet by post-drilling, and the filter element casing is pre-buried at the above-ground well wall water inlet.

[0035] Specifically, in this embodiment, the widened crown beam extends into the well to a width of 200-300 mm, and forms a horizontal load-bearing system with the cross support beam.

[0036] Specifically, in this embodiment, the load-bearing member is 16# channel steel, which is laid on the cross support beam at a spacing of 900mm, and the ends are welded and fixed to the embedded steel plates of the widened crown beam, with the weld height being ≥8mm.

[0037] Specifically, in this embodiment, the frame is a disc-type frame, with an erection height of ≤5m, a vertical distance × a horizontal distance of the vertical poles of ≤900mm×900mm, and a step distance of ≤1500mm.

[0038] Specifically, in this embodiment, the disc-type frame is provided with an oblique brace, and the oblique brace is provided every three spans along the longitudinal direction, with an angle of 45°-60° with the horizontal plane.

[0039] Specifically, in this embodiment, the filter element installed by drilling a hole in the underground well wall includes a double-layer filter layer, the inner layer is gravel with a particle size of 10-20 mm, and the outer layer is gravel with a particle size of 50-80 mm. The thickness of each layer is 1 / 2 of the well wall thickness.

[0040] Specifically, in this embodiment, the outer layer of the filter element is wrapped with 20-mesh galvanized wire mesh, fixed to the well wall by M12 bolts at a spacing of 300 mm, and the bolt holes are sealed with epoxy resin.

[0041] Specifically, in this embodiment, the above-ground well wall filter sleeve is fixed to the well wall reinforcement by welding Φ12 reinforcement, with a positioning deviation of ≤3mm, and the sleeve is pre-filled with a crushed stone filter layer with a particle size of 10-20mm.

[0042] Specifically, in this embodiment, the above-ground well wall is cast in sections along the height direction, with each section casting height ≤3m, and the upper layer is cast after the lower layer concrete strength is ≥75% of the design value.

[0043] Specifically, in this embodiment, the frame is connected to the ground well wall template through cross bar supports, and the distance between the cross bar supports is ≤1200mm, forming a rigid connection system.

[0044] Specifically, in this embodiment, the present invention provides a large-diameter water well construction method, including the following key technical details: Mechanical design of widened crown beam (refer to Figure 2): Design principle: The widened part of the crown beam is used as a cantilever beam with a calculated span of L=300mm. It bears the concentrated load F=25kN transmitted by the channel steel (single channel steel end load). C35 concrete is used, and the reinforcement is 6Φ16 (HRB400). It meets the bending bearing capacity requirement of M=FL=7.5kN·m.

[0045] Construction points: The widened crown beam should be cast at the same time as the original crown beam, the anchorage length of the steel bar extending into the original crown beam should be ≥300mm, and the embedded steel plate should be avoided when vibrating the concrete to ensure that the bonding strength between the steel plate and the concrete is ≥1.2MPa.

[0046] Channel steel-cross beam collaborative load-bearing system: Load transfer path: manhole cover load (785kN) → formwork → secondary purlin (wooden square) → main purlin (double steel pipe) → buckle frame upright → channel steel → cross beam → underground manhole wall.

[0047] Connection structure: The channel steel and the cross beam are fixed by U-shaped clips (made of ∠50×5 angle steel), the clip spacing is 900mm, and the welding length with the channel steel is ≥50mm; the channel steel and the embedded steel plate of the widened crown beam are double-sided welded, the weld length is 100mm, the thickness is 8mm, and it has passed the UT test level I.

[0048] Anti-overturning design of the buckle frame: Stability verification: frame height H=5m, column slenderness ratio λ=μh / i=1.5×1500 / 15.8≈142, stability coefficient φ=0.33 is obtained from the table, single column bearing capacity N=φAf=0.33×489×205≈33.2kN>design load 25kN, which meets the requirements.

[0049] Three-dimensional reinforcement measures: ・Horizontal direction: set a horizontal scissors brace every 3 steps, with a width of 6m; ・Vertical direction: Vertical diagonal braces are set every 5 spans along the four sides of the frame and in the longitudinal and transverse directions inside, with an angle of 50°, forming a "well" support network.

[0050] Principle of underground filter element post-drilling process (see Figure 3): Filter layer design: The inner layer with fine particles (10-20mm) intercepts fine-grained sediment (d≤0.1mm), and the outer layer with coarse particles (50-80mm) provides skeleton support. The thickness of the two layers is 1 / 2 of the well wall thickness (for example, when the well wall thickness is 600mm, the thickness of each layer is 300mm). Gradient filtration of "cutting off fine and retaining coarse" is achieved through particle size grading.

[0051] Anti-leakage structure: The gap between the galvanized wire mesh (mesh size 2mm×2mm) and the well wall is filled with epoxy resin mortar, and rubber sealing rings are installed in the bolt holes. After water pressure test (0.2MPa), the leakage rate is ≤0.01L / (m・min).

[0052] Innovation of pre-buried filter sleeve on the ground (see Figure 4): Selection of finished casing: DN300PVC-U water filter pipe is used, with prefabricated annular ribs on the inner wall (spacing 200mm) to enhance the bond with concrete. Casing length = well wall thickness + 200mm (extending 100mm on each side).

[0053] Pre-filling of the filter layer: The casing is filled with 10-20mm diameter gravel to 1 / 2 of its height, forming a "bottom-up" permeable path to avoid blockage by concrete inflow during pouring. The water flow test showed that the permeability rate reached 1.2m³ / h, which is twice that of the traditional pre-buried process.

[0054] Embodiment: A method for constructing a large-diameter water well comprises the following steps: 1. Construction preparation stage (construction period: 5 days) Geological survey review: Use geological radar to detect the distribution of soil layers at the underground well location, focusing on confirming that the bearing capacity characteristic value fak of the bearing layer below the cross beam is ≥ 150kPa. If it is not met, C15 concrete replacement treatment will be used.

[0055] Special design of the frame: entrust a professional unit to carry out the design of the interlocking frame, issue a "High-rise Formwork Safety Calculation Book", clarify the arrangement of vertical poles, diagonal bracing angles and load-bearing verification, and implement it after approval by experts.

[0056] 2. Underground structure construction (construction period: 20 days) Crown beam widening construction: Rebar binding: The newly added wide part of the steel bar is mechanically connected to the original crown beam main bar (straight thread sleeve), the joint grade is I, and the sampling rate is 10%.

[0057] Formwork support: Use 15mm thick wooden formwork, the back ribs are 100mm×100mm square wood, the spacing is 300mm, and the reinforcement is done by tension bolts (Φ14@600mm).

[0058] Concrete pouring: Use automobile pump for pumping, slump 160±20mm, layered pouring thickness ≤500mm, vibrator inserted into the lower layer of concrete 50-100mm, curing time 14 days.

[0059] Channel steel laying and welding: Measurement and layout: Pop out the channel steel positioning line on the top surface of the cross beam, with an error of ≤2mm. Use a level to control the elevation of the top surface of the channel steel, with a flatness of ≤3mm / 10m.

[0060] Welding process: Rod drying temperature is 150℃, constant temperature is 1 hour, welding current is 180-220A, after welding, weld appearance inspection (no undercut, slag inclusion) and UT inspection (sampling rate 20%) are carried out.

[0061] 3. Filter element installation and construction (construction period: 15 days) Underground well wall back drilling: Equipment selection: Use ZQ-100 water drill rig, the drill bit diameter is determined according to the outer diameter of the filter element + 20mm (for example, the outer diameter of the filter element is 280mm, and the drill bit diameter is 300mm), and the verticality deviation of the drilling hole is ≤1%.

[0062] Filter element assembly: First fill in the inner layer of gravel with a compaction degree of ≥90%, then lay the galvanized wire mesh (lap length 50mm), and finally fill in the outer layer of gravel. Use a torque wrench to tighten the bolts with a torque value of 40-50N·m.

[0063] Pre-buried casing on the ground well wall: Positioning and laying out: Mark the center position of the casing on the steel mesh of the well wall with red paint, with an error of ≤3mm. Use the skip welding process when welding the casing to the main reinforcement to avoid overheating and brittle fracture of the steel bars.

[0064] Pipe mouth protection: Wrap both ends of the casing with gauze and tie it with tape to prevent concrete from entering. Check the integrity of the gauze before pouring and replace it in time if it is damaged.

[0065] 4. Innovations in Quality Control Three stages of rack acceptance: Foundation acceptance: After the channel steel is laid, use a level to check the elevation deviation (≤±5mm) and a steel ruler to check the spacing (≤±10mm); Acceptance during erection: After every two steps of the frame are erected, the verticality of the vertical poles (≤5mm / layer) and the spacing between the horizontal poles (≤±20mm) are checked; Acceptance before pouring: The joint supervision unit will inspect the overall stability of the frame and use a total station to measure the horizontal displacement of the top of the frame (≤10mm).

[0066] Filter element functionality test: Underground filter element: After installation, conduct a water flow test. Use a flow meter to measure the water permeability (≥0.5m³ / h) and a turbidity meter to detect the sediment content of the effluent (≤5NTU). Above-ground filter element: After the casing is embedded, a pull-out test is carried out, using a jack to load it to 10kN for 5 minutes, and the casing displacement is ≤2mm.

[0067] In summary, compared with the prior art, the present invention has the following beneficial effects: (1) Improved safety performance Formwork risk level reduction: Formwork height is reduced from 13.53m to 5m. Frame erection is classified as a "highly dangerous sub-project" (not super-dangerous), and no expert review is required, reducing safety management costs by 40%.

[0068] Enhanced anti-overturning ability: Through the horizontal load-bearing system of channel steel and diagonal bracing, the anti-overturning coefficient of the frame is increased from 1.1 of the traditional process to 1.8, meeting the requirements of the "Uniform Standard for Safety Technology of Construction Scaffolding" GB51210.

[0069] (2) Breakthrough in quality control Template forming accuracy: The rigidity of the buckle frame is 60% higher than that of the traditional steel pipe frame, the center deflection of the manhole cover template is ≤15mm (50mm for traditional process), and the concrete surface flatness is ≤5mm (10mm for traditional process), meeting the standard of fair-faced concrete.

[0070] The filter element is long-lasting and reliable: the underground filter element has a filtration efficiency of 96% (70% for traditional processes), the above-ground filter element has a positioning error of 3mm (10mm for traditional processes), the water inlet sedimentation period is extended to 12-18 months, and maintenance costs are reduced by 60%.

[0071] (3) Significant economic benefits The cost of erecting the frame has been reduced from 85 yuan / m³ to 58 yuan / m³, a decrease of 31.8%; The construction period was shortened from 80 days to 55 days, a reduction of 25 days (a decrease of 31.25%); The cost of handling quality defects was reduced from 120,000 yuan to 24,000 yuan, a reduction of 80%.

[0072] (IV) Environmental benefits It reduces the amount of high-altitude work by 60% and construction dust by 30% (the dust generated by the assembly of the screw-type frame is less than that of the traditional steel pipe frame), meeting the requirements of the green construction guidelines.

[0073] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A method for constructing a large-diameter water well, characterized in that: The following steps are involved: Step S1: pouring the underground well wall, ring beam and widened crown beam, wherein the widened crown beam extends into the well to form a frame support platform; Step S2: laying load-bearing components on the cross support beam, wherein the load-bearing components are fixedly connected to the widened crown beam; Step S3: Building a frame based on the load-bearing components to support the large manhole cover template and the above-ground manhole wall template; Step S4: The filter element is installed at the underground well wall water inlet by post-drilling, and the filter element casing is pre-buried at the above-ground well wall water inlet.

2. A large-diameter water well construction method according to claim 1, characterized in that: The widened crown beam extends into the well with a width of 200-300 mm, and forms a horizontal load-bearing system with the cross support beam.

3. A large-diameter water well construction method according to claim 1, characterized in that: The load-bearing components are 16# channel steel, which are laid on the cross support beam at a spacing of 900mm, and the ends are welded and fixed to the embedded steel plates of the widened crown beam, with the weld height ≥8mm.

4. A large-diameter water well construction method according to claim 1, characterized in that: The frame is a disc-type frame with an erection height of ≤5m, a vertical distance × a horizontal distance of the uprights of ≤900mm×900mm, and a step distance of ≤1500mm.

5. A large diameter water well construction method according to claim 4, characterized in that: The disc-shaped frame is provided with an oblique brace, and the oblique brace is provided every three spans along the longitudinal direction, and the angle with the horizontal plane is 45°-60°.

6. A large diameter water well construction method according to claim 1, characterized in that: The filter element installed in the hole drilled behind the underground well wall includes a double-layer filter layer, the inner layer is gravel with a particle size of 10-20mm, and the outer layer is gravel with a particle size of 50-80mm. The thickness of each layer is 1 / 2 of the well wall thickness.

7. A large-diameter water well construction method according to claim 6, characterized in that: The outer layer of the filter element is wrapped with 20-mesh galvanized wire mesh and fixed to the well wall with M12 bolts at a spacing of 300mm, and the bolt holes are sealed with epoxy resin.

8. A large diameter water well construction method according to claim 1, characterized in that: The above-ground well wall filter cartridge is fixed to the well wall reinforcement by welding with Φ12 reinforcement, with a positioning deviation of ≤3mm. The above-ground well wall filter cartridge is pre-filled with a crushed stone filter layer with a particle size of 10-20mm.

9. A large diameter water well construction method according to claim 1, characterized in that: The above-ground well wall is cast in sections along the height direction, with each section casting height ≤3m, and the upper layer is cast after the lower layer concrete strength is ≥75% of the design value.

10. A large diameter water well construction method according to claim 1, characterized in that: The frame is connected to the ground well wall template through cross bar supports, and the cross bar support spacing is ≤1200mm, forming a rigid connection system.

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