A design and construction method for applying PHC piles and TSC piles to a communication iron tower fast-mounting foundation

Abstract

This invention discloses a design and construction method for applying PHC piles and TSC piles to the rapid installation foundation of communication towers, belonging to the field of communication infrastructure technology. The method includes: foundation grading and selection, pile foundation parameter design, tower foundation matching, rapid installation component design, and rapid construction technology. Based on the tower height and combined load, PHC single piles, PHC pile groups, or TSC piles are selected in stages. Factory prefabrication, 170–190℃ high-temperature autoclave curing, ±2mm high-precision positioning, multiple connection guarantees, and rapid on-site assembly are employed to achieve industrialized rapid installation of communication tower foundations. Compared with traditional processes, the curing time is shortened from 28 days to 3 days, the total construction period is shortened from 30 days to 5 days, the installation accuracy is improved from ±10mm to ±2mm, the overall cost is reduced by 20%–30%, and the environmental benefits are significant. It is suitable for rapid deployment scenarios such as 5G base stations, power towers, and monitoring towers.

Description

Technical Field

[0001] This invention relates to the field of communication infrastructure technology, specifically to a design and construction method for systematically applying prestressed concrete pipe piles (PHC piles) and high-strength concrete thin-walled steel pipe piles (TSC piles) to the rapid installation foundation of communication towers. Background Technology

[0002] Traditional communication tower foundations primarily utilize on-site concrete casting, which suffers from technical bottlenecks such as long construction periods, difficulty in quality control, low installation accuracy, significant environmental impact, and high overall costs, failing to meet the rapid deployment requirements of 5G base stations. Existing technologies for PHC piles and TSC piles in communication tower foundations suffer from systemic deficiencies, lacking a complete design framework, scientific selection criteria, reliable connection mechanisms, and hierarchical optimization schemes. Furthermore, their low level of industrialization hinders the full realization of the advantages of precast piles' factory production and rapid on-site installation. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the purpose of this invention is to provide a design and construction method for applying PHC piles and TSC piles to the quick-installation foundation of communication towers. This method combines factory prefabrication with rapid on-site installation, significantly shortening the construction cycle, improving project quality, reducing overall costs, and achieving green and environmentally friendly construction.

[0004] This invention discloses a design and construction method for applying PHC piles and TSC piles to the quick-installation foundation of communication towers, characterized by comprising the following steps:

[0005] (1) Foundation type selection: Based on the height of the communication tower and the combined load, the pile type is determined by the graded load calculation method. The combined load includes wind load, seismic load and vertical self-weight load. When the tower height is ≤20m and the design load is ≤500kN, PHC single pile is selected. When the tower height is 25~30m and the design load is 500~1000kN, a pile group consisting of 4 PHC piles is selected. When the tower height is ≤25m and the design load is ≤800kN, TSC pile is selected.

[0006] (2) Pile foundation parameter design: Based on geological conditions, tower load and pile type, determine pile diameter, wall thickness, pile length, prestressing type and concrete strength grade;

[0007] (3) Tower-pile matching connection: Design connection structure for different pile types to achieve reliable force transmission and precise positioning between pile foundation and tower base;

[0008] (4) Prefabrication of quick-assembly components: The connecting flange, positioning mechanism, threaded sleeve and end plate are prefabricated in the factory in a standardized manner and cured in a high temperature autoclave.

[0009] (5) Rapid on-site construction: Piles are driven by pre-drilling process, and the components are hoisted, precisely positioned, bolted and leveled on-site.

[0010] Preferably, in step (1): the PHC single pile is PHC-400AB-95 or PHC-600AB-110, with a pile diameter of 400-600mm, and the pile diameter is limited to no more than 600mm due to construction machinery restrictions; the PHC group pile consists of 4 PHC-400AB-95 piles, with a single pile diameter of 400-500mm, and the pile diameter is limited to no more than 500mm due to site restrictions, arranged in a square, with a pile spacing of 3 times the pile diameter;

[0011] The TSC pile is designated as TSC-Ⅰ-600-110-10-12, with a pile diameter of 600mm. Due to construction machinery limitations, the pile diameter cannot exceed 600mm.

[0012] Preferably, in step (2): the parameters of the PHC single pile are: diameter 400-600mm, wall thickness 95-110mm, pile length 9-12m, and concrete strength grade ≥C80;

[0013] The parameters of a single pile in the PHC pile group are: diameter 400-500mm, wall thickness 95-100mm, pile length 12m, and concrete strength grade ≥C80.

[0014] The TSC pile parameters are as follows: outer diameter 600mm, steel pipe wall thickness 10mm, inner concrete wall thickness 110mm, pile length 12m, concrete strength grade ≥C80, and hot-dip galvanizing for corrosion protection on the outer wall of the steel pipe.

[0015] Preferably, the tower-pile matching connection in step (3) specifically refers to:

[0016] The upper end of PHC monopile, PHC group pile and TSC pile is provided with an end plate. The end plate is provided with through holes for high-strength bolts to pass through. Threaded sleeves are pre-embedded in the positions corresponding to the through holes. A connecting flange is installed above the end plate. The connecting flange is provided with high-strength bolts passing through the through holes and the connecting threaded sleeves. The effective engagement depth of the bolts is not less than 120mm.

[0017] Preferably, the tower-pile connections are all protected by multiple safeguards: the main connection is a high-strength bolt fastening connection;

[0018] The auxiliary connection is a welded reinforcement connection; the tower and pile positioning method is a combination of high-precision mechanical positioning and laser calibration, and the installation accuracy is controlled within ±2mm; the anti-loosening method between the tower and the connecting flange is to use anti-loosening nuts, spring washers or thread locking agents; the anti-corrosion method is to use galvanizing, fluorocarbon coating or sealant sealing treatment on the metal surface.

[0019] Preferably, the quick-assembly component prefabrication in step (4) specifically includes: the end plate, connecting flange, and threaded sleeve are prefabricated in the factory; the positioning mechanism is an adjustable high-precision positioning component to ensure that the pile position, elevation, and verticality deviation are ≤ ±2mm; all component interface dimensions are uniform to achieve modular transportation and rapid on-site assembly.

[0020] Preferably, the high-temperature autoclave curing process in step (4) is as follows: PHC piles and precast components are cured with high-temperature and high-pressure steam at a temperature of 170-190℃ and a curing time of ≤3 days, so that the concrete strength can quickly reach more than 95% of the design strength.

[0021] Preferably, the rapid on-site construction in step (5) specifically involves: first, leveling and surveying the site; then, using a pre-drilling process to eliminate geological obstacles; and finally, static pressure or vibratory pile driving; the pile top is backfilled and reinforced with cement grout; after the connecting flange is hoisted, it is quickly centered through a positioning mechanism; after the bolts are tightened, leveling and verticality correction are performed; the total on-site foundation installation time is ≤2 days.

[0022] Preferably, it also includes an integrated reinforcement system of pile top-end plate-flange: local reinforcement and densification of the concrete at the pile top; the end plate thickness is ≥28mm, and it is reliably welded or anchored to the main reinforcement of the pile body.

[0023] Preferably, a quality verification system is adopted after construction is completed, including non-destructive testing of pile integrity, bolt torque testing, weld non-destructive testing, verticality testing, and static load testing, to ensure that the foundation bearing capacity, deformation, and stability meet the design requirements.

[0024] The significant advantages of this invention's technical solution are: curing time is shortened from 28 days to 3 days, a reduction of ≥89%; total construction period is shortened from 30 days to 5 days, a reduction of ≥83%; on-site installation is shortened from 7-10 days to 1-2 days, a reduction of ≥73%; installation accuracy is improved from ±10mm to ±2mm, an improvement of 5 times; overall cost is reduced by 20%-30%, and labor cost is reduced by 40%; construction pollution is reduced by more than 80%; and connection safety factor is improved by more than 30%. Attached Figure Description

[0025] Figure 1 It is a construction process flow chart;

[0026] Figure 2 This is a schematic diagram of a hierarchical design system;

[0027] Figure 3 It is a 3D view of the connecting flange;

[0028] Figure 4 This is a schematic diagram of the connection between a 20m iron tower and a PHC monopile;

[0029] Figure 5 This is a schematic diagram of the connection between a 25–30m iron tower and a PHC pile group;

[0030] Figure 6 This is a schematic diagram of the connection between a 25m iron tower and a TSC pile. Detailed Implementation

[0031] Example 1: PHC monopile quick-installation foundation for a 20m communication tower

[0032] 1. Project Overview: Tower height: 20m; Design combined load: 450kN (including vertical load, wind load, and seismic load); Geological conditions: silty clay, characteristic value of foundation bearing capacity fak≥180kPa; Pile type selection: PHC-600AB-110 monopile.

[0033] 2. Detailed implementation steps, Step 1: Load and pile foundation design: Calculate the combined load based on the tower height, site type, basic wind pressure, and seismic fortification intensity, and determine the foundation control load to be 450kN.

[0034] Based on geological conditions and load requirements, PHC-600AB-110 monopile was selected, with a pile diameter of 600mm, a wall thickness of 110mm, a pile length of 9m, a concrete strength grade of C80, and AB type medium prestressed concrete.

[0035] Step 2: Factory Prefabrication of Components: Standardized fabrication of PHC pile A1, connecting flange A2, end plate A3, and threaded sleeve A4 is completed in the factory.

[0036] 1) Reinforcing steel cage fabrication: Main reinforcement and stirrups are tied according to design dimensions, and tensioning ends are set; 2) Concrete pouring: C80 high-strength concrete is used, centrifugally molded; 3) High-temperature autoclave curing: The concrete is placed in a high-temperature, high-pressure curing autoclave at 170–190℃ for 3 days, achieving a strength of over 95% of the design value; 4) End plate and threaded sleeve pre-embedding: The end plate thickness is 28mm, with 16 sets of M24 threaded sleeves pre-embedded (aligned with the holes on the end plate), with an effective screw-in depth of 120mm; 5) Connecting flange processing: Custom-made single-pile connecting flanges are used, with anti-corrosion galvanizing treatment. The connecting flange includes a flange top plate A21, a flange bottom plate A22, and a circular pipe A25 connecting the flange top plate and the flange bottom plate. An intermediate flange plate A23 is welded and fixed to the outer periphery of the middle of the circular pipe. Reinforcing ribs A24 (e.g., evenly distributed radially) are welded and fixed between the flange top plate, flange bottom plate, and intermediate flange plate. Figure 3 (As shown).

[0037] Step 3: On-site preparation: 1) Site leveling: Clean the construction area, level and compact it; 2) Surveying and setting out: Use a total station to locate the center of the pile, mark the pile position, and control the error within ±2mm; 3) Equipment arrival: Static pressure pile driver, hoisting equipment and surveying equipment are in place and debugged.

[0038] Step 4 Pile Foundation Construction: 1) Pre-hole construction: Use a small drilling rig to pre-hole and eliminate obstacles such as hard layers and rocks; 2) Pile driving construction: Use static pressure method to drive piles, control the verticality ≤1%, and achieve the design elevation; 3) Pile top treatment: Clean the top surface of the pile head to ensure that the end plate is flat and clean.

[0039] Step 5 Basic Installation: 1) Install the connecting flange, use M24 high-strength bolts to tighten the bottom plate and end plate of the connecting flange, and apply pre-tightening force according to the design torque; 2) Auxiliary reinforcement: Weld and reinforce the contact part between the connecting flange and the end plate; 3) Backfilling and sealing: Use non-shrink cement grout to backfill around the pile top and compact it.

[0040] Step 6 Quality Inspection and Acceptance: 1) Pile body integrity: Non-destructive testing using low strain method; 2) Connection quality: Check bolt torque, weld appearance, and dimensional accuracy; 3) Bearing capacity verification: Conduct static load test to meet the design load requirement of 450kN; 4) Verticality inspection: The verticality of the tower installation surface meets the specification requirements.

[0041] Step 7: Tower Installation: After the foundation passes inspection, hoist tower A5. The base plate at the bottom of tower A5 is bolted to the flange top plate of the connecting flange to complete the overall installation.

[0042] To further enhance the support effect, step 7 can be replaced with the following steps: First, pour a second layer of concrete block A8 above the flange top plate. Concrete block A8 contains a pre-embedded bolt assembly A10 (including bolts and washers) for connection to the flange top plate. Hoist the tower A5 above the concrete block A8. Connect and fix the tower base plate A9 at the bottom of tower A5 to the bolt assembly, completing the overall installation (e.g., Figure 4 (As shown).

[0043] Example 2: PHC group pile quick-installation foundation for 30m communication tower

[0044] 1. Project Overview: Tower height: 30m; Design combined load: 800kN;

[0045] Geological conditions: silty clay mixed with a small amount of gravel, fak≥200kPa; Pile type selection: 4 PHC-400AB-95 piles.

[0046] 2. Detailed Implementation Steps

[0047] Step 1: Load and pile group layout design: Perform combined calculations of wind load, seismic action, and vertical load to determine the control load of 800kN.

[0048] The pile group consists of four PHC-400AB-95 A6 single piles, each with a diameter of 400mm, a wall thickness of 95mm, a length of 12m, and C80 concrete. The piles are arranged in a square with a center-to-center spacing of 1200mm (3 times the pile diameter).

[0049] Step 2 Factory Prefabrication: 1) Prefabrication of pile groups: Complete PHC piles A6 in the factory, 4 piles form a pile group, and pre-embed end plates A3 and threaded sleeves A4 on the pile group; 2) Fabrication of connecting flanges A2, with reinforced rib structure; 3) Curing: High temperature autoclave curing for 3 days; 4) Corrosion protection: Hot-dip galvanizing treatment of connecting flanges, end plates and pre-embedded parts.

[0050] Step 3: On-site preparation: 1) Level and compact the site; 2) Use a total station to mark the center points of four pile positions and draw crosshairs; 3) Position construction machinery and hoisting equipment.

[0051] Step 4: Pile group construction: 1) Drill holes for each pile to ensure the verticality of the holes; 2) Drive the piles in sequence by static pressure to control the consistent elevation of the pile tops; 3) After the piles are driven, check the pile position deviations to ensure that they meet the design requirements.

[0052] Step 5: Installation of the connecting flange: 1) Hoist the connecting flange and fit it onto the top of the 4 piles; 2) Use a positioning mechanism (including the positioning holes on the end plate and the positioning pins on the connecting flange) to calibrate, with a plane error ≤ ±2mm and a levelness error ≤ 1‰; 3) Install the integral flange to connect the 4 piles into a single load-bearing structure; 4) Tighten the bolts and reinforce with welding.

[0053] Step 6 Quality Inspection: 1) Pile body integrity inspection; 2) Bolt torque sampling inspection; 3) Weld non-destructive testing; 4) Overall bearing capacity and deformation test of pile group.

[0054] Step 7: Tower installation: After the foundation passes inspection, hoist the tower, adjust its plumbness, fix it, and conduct final inspection.

[0055] Example 3: Quick-installation foundation for 25m communication tower TSC pile

[0056] 1. Project Overview: Tower height: 25m; Design combined load: 700kN; Geological conditions: Coastal soft soil area with high wind pressure; Pile type selection: TSC-Ⅰ-600-110-10-12 monopile.

[0057] 2. Detailed Implementation Steps

[0058] Step 1: Load and pile design: Based on the requirements of high wind pressure and seismic resistance, load combination is carried out, and the design load of 700kN is determined.

[0059] TSC high-strength concrete thin-walled steel pipe piles were selected, with an outer diameter of 600mm, a steel pipe wall thickness of 10mm, an inner concrete wall thickness of 110mm, a pile length of 12m, C80 concrete, and hot-dip galvanized steel pipe outer wall for corrosion protection.

[0060] Step 2 Factory Prefabrication: 1) Steel pipe rolling, welding, and rounding; 2) Inner layer concrete pouring, centrifugal molding, and high-temperature curing for 3 days; 3) Pre-embedding of end plates, shear keys, and threaded sleeves; 4) Processing of connecting flanges.

[0061] Step 3: On-site preparation: 1) Leveling the site; 2) Accurately marking out the pile positions; 3) Positioning the vibratory pile driving equipment.

[0062] Step 4: Pile foundation construction: 1) Pre-drilling treatment to adapt to soft soil areas; 2) Vibratory pile driving to the design elevation and controlling verticality; 3) Cleaning and leveling the pile top.

[0063] Step 5 Tower-Pile Connection Installation: 1) Hoist the connecting flange; 2) High-precision positioning, error ≤ ±2mm; 3) Use M33 high-strength bolts for connection, with an effective engagement depth of 120mm; 4) Set shear keys to improve horizontal load and pull-out resistance; 5) Weld reinforcement and seal for corrosion protection.

[0064] Step 6 Quality Inspection: 1) Pile body integrity inspection; 2) Inspection of bolts, welds, and anti-corrosion layer; 3) Bearing capacity, verticality, and horizontal displacement test.

[0065] Step 7: Tower Installation: Install the tower, adjust its verticality, and complete the overall structural fixing and acceptance.

[0066] Comparison of the advantages of the improved technology of this invention:

[0067] This invention selects PHC monopiles, PHC group piles, or TSC piles based on the tower height and combined load classification. It employs factory prefabrication, high-temperature autoclave curing at 170–190℃, ±2mm high-precision positioning, multiple connection guarantees, and rapid on-site assembly to achieve industrialized rapid installation of communication tower foundations. Compared with traditional processes, curing time is shortened from 28 days to 3 days, the total construction period is shortened from 30 days to 5 days, installation accuracy is improved from ±10mm to ±2mm, overall cost is reduced by 20%–30%, and environmental benefits are significant. It is suitable for rapid deployment scenarios such as 5G base stations, power towers, and monitoring towers.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A design and construction method for applying PHC piles and TSC piles to the quick-installation foundation of communication towers, characterized in that, Includes the following steps: (1) Foundation type selection: Based on the height of the communication tower and the combined load, the pile type is determined by the graded load calculation method. The combined load includes wind load, seismic load and vertical self-weight load. When the tower height is ≤20m and the design load is ≤500kN, PHC single pile is selected. When the tower height is 25~30m and the design load is 500~1000kN, a pile group consisting of 4 PHC piles is selected. When the tower height is ≤25m and the design load is ≤800kN, TSC pile is selected. (2) Pile foundation parameter design: Based on geological conditions, tower load and pile type, determine pile diameter, wall thickness, pile length, prestressing type and concrete strength grade; (3) Tower-pile matching connection: Design connection structure for different pile types to achieve reliable force transmission and precise positioning between pile foundation and tower base; (4) Prefabrication of quick-assembly components: The connecting flange, positioning mechanism, threaded sleeve and end plate are prefabricated in the factory in a standardized manner and cured in a high temperature autoclave. (5) Rapid on-site construction: Piles are driven by pre-drilling process, and the components are hoisted, precisely positioned, bolted and leveled on-site.

2. The design and construction method according to claim 1, characterized in that, In step (1): the PHC single pile is PHC-400AB-95 or PHC-600AB-110, with a pile diameter of 400-600mm. Due to the limitations of construction machinery, the pile diameter is not greater than 600mm. The PHC group pile consists of 4 PHC-400AB-95 piles, with a single pile diameter of 400-500mm. Due to the limitations of the site, the pile diameter is not greater than 500mm. They are arranged in a square, and the pile spacing is 3 times the pile diameter. The TSC pile is designated as TSC-Ⅰ-600-110-10-12, with a pile diameter of 600mm. Due to construction machinery limitations, the pile diameter cannot exceed 600mm.

3. The design and construction method according to claim 2, characterized in that, In step (2): the parameters of the PHC single pile are: diameter 400-600mm, wall thickness 95-110mm, pile length 9-12m, and concrete strength grade ≥C80. The parameters of a single pile in the PHC group are: diameter 400-500mm, wall thickness 95-100mm, pile length 12m, and concrete strength grade ≥C80. The TSC pile parameters are as follows: outer diameter 600mm, steel pipe wall thickness 10mm, inner concrete wall thickness 110mm, pile length 12m, concrete strength grade ≥C80, and hot-dip galvanizing for corrosion protection on the outer wall of the steel pipe.

4. The design and construction method according to claim 1, characterized in that, The tower-pile matching connection mentioned in step (3) specifically refers to: The upper end of PHC monopile, PHC group pile and TSC pile is provided with an end plate. The end plate is provided with through holes for high-strength bolts to pass through. Threaded sleeves are pre-embedded in the positions corresponding to the through holes. A connecting flange is installed above the end plate. The connecting flange is provided with high-strength bolts passing through the through holes and the connecting threaded sleeves. The effective engagement depth of the bolts is not less than 120mm.

5. The design and construction method according to claim 4, characterized in that, The tower-pile connection is reinforced with multiple safeguards: the main connection is a high-strength bolt fastening connection; The auxiliary connection is a welded reinforcement connection; the tower and pile positioning method is a combination of high-precision mechanical positioning and laser calibration, and the installation accuracy is controlled within ±2mm; the anti-loosening method between the tower and the connecting flange is to use anti-loosening nuts, spring washers or thread locking agents; the anti-corrosion method is to use galvanizing, fluorocarbon coating or sealant sealing treatment on the metal surface.

6. The design and construction method according to claim 1, characterized in that, The prefabrication of quick-assembly components in step (4) specifically includes: end plates, connecting flanges, and threaded sleeves are prefabricated in the factory; the positioning mechanism is an adjustable high-precision positioning component to ensure that the pile position, elevation, and verticality deviation are ≤ ±2mm; all component interface dimensions are uniform to achieve modular transportation and rapid on-site assembly.

7. The design and construction method according to claim 1, characterized in that, The high-temperature autoclave curing process described in step (4) is as follows: PHC piles and precast components are cured with high-temperature and high-pressure steam at a temperature of 170–190℃ and a curing time of ≤3 days, so that the concrete strength can quickly reach more than 95% of the design strength.

8. The design and construction method according to claim 1, characterized in that, The on-site rapid construction described in step (5) is as follows: first, the site is leveled and surveyed, and geological obstacles are eliminated by using the pre-drilling process, and then static pressure or vibratory pile driving is carried out; the pile top is backfilled and reinforced with cement grout; after the connecting flange is hoisted, it is quickly centered by the positioning mechanism, and after the bolts are tightened, leveling and verticality correction are carried out; the total on-site foundation installation time is ≤2 days.

9. The design and construction method according to claim 1, characterized in that, It also includes an integrated reinforcement system for pile top-end plate-flange: local reinforcement and densification of the concrete at the pile top; the end plate thickness is ≥28mm, and it is reliably welded or anchored to the main reinforcement of the pile body.

10. The design and construction method according to claim 1, characterized in that, After construction is completed, a quality verification system is adopted, including non-destructive testing of pile integrity, bolt torque testing, weld non-destructive testing, verticality testing, and static load testing, to ensure that the foundation bearing capacity, deformation, and stability meet the design requirements.

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