High-voltage line under low-clearance cast-in-place pile power fence safety protection construction method

Abstract

The application relates to the technical field of construction protection structures, and discloses a high-voltage line under low-clearance cast-in-place pile electric power fence safety protection construction method, which comprises the following construction steps: 1) an electric power fence structure is arranged on a construction site, the electric power fence structure comprises a top fence and a vertical fence; 2) a pile site is reserved on the construction site, and the top fence is spaced from the construction site to form a fence area; and 3) a row of warning poles is arranged between the construction site and an extra-high voltage projection area, and colored ribbon flags are bound between adjacent warning poles to form the vertical fence. Through the arrangement of the top fence and the vertical fence, the height of the fence in the vertical direction in the construction process can be limited, vehicles are prohibited from driving out of the vertical fence, the high-voltage line is prevented from being touched, the mechanical equipment exceeding the height of the fence is prevented from entering the fence area, and the top fence and the vertical fence formed by the colored ribbon flags are eye-catching, thereby achieving a good warning effect.

Description

Technical Field

[0001] This invention relates to the technical field of construction protection structures, and more specifically, to a construction method for safety protection of power grid sealing of low-headroom cast-in-place piles under high-voltage lines. Background Technology

[0002] With the rapid development of urbanization, there are increasing spatial conflicts between the planning and construction of municipal infrastructure and overhead power lines inside and outside the city. Undertaking foundation engineering construction within the protection range of 110KV high-voltage lines not only threatens the safe operation of high-voltage power lines, but also directly threatens the safety of construction personnel. Therefore, it is crucial to ensure the safety and reliability of construction under 110KV high-voltage lines, especially under low-headroom high-voltage lines.

[0003] Construction within the protection zone of a 110KV high-voltage line requires maintaining safe control distances in both vertical and horizontal directions and setting up warning lines. Therefore, when the safe construction height for cast-in-place piles is insufficient, there are issues such as limited height for activities like pile drilling, steel cage hoisting, and concrete pouring, resulting in significant construction safety risks. Summary of the Invention

[0004] The purpose of this invention is to provide a construction method for the safety protection of power grid sealing of cast-in-place piles under high-voltage lines with low clearance, aiming to solve the problems of limited construction height and high safety risks of cast-in-place piles under high-voltage lines with low clearance in the existing technology.

[0005] This invention is implemented as follows: a construction method for safety protection of power grid enclosure for low-headroom cast-in-place piles under high-voltage lines, comprising the following construction steps:

[0006] 1) Level the construction site at the foundation pit location under the high voltage line. A power grid structure is set up on the construction site. The high voltage line has a high voltage projection area projected longitudinally onto the ground. The power grid structure includes a top grid and a vertical grid.

[0007] 2) Reserve pile positions on the construction site, and pour column foundations on both sides of the pile positions to form multiple lattice columns along the direction of the pile positions. The multiple lattice columns are arranged in two rows on both sides of the pile positions. Stretch height limit ropes and tie colored flags on the top of the lattice columns to form a crisscrossing top net. The top net is separated from the construction site to form a net area. The high-voltage projection area includes an inner high-voltage projection area located within the net area and an outer high-voltage projection area located outside the net area.

[0008] 3) A row of warning poles is set up between the construction site and the external high-voltage projection area, and colored flags are tied between adjacent warning poles to form the vertical enclosure net;

[0009] 4) Drive the low-headroom rotary drilling rig into the sealed area, and use the low-headroom rotary drilling rig to rotary drill the pile positions in the sealed area to form multiple pile holes. Use a slag hopper to clean the multiple pile holes once.

[0010] 5) Fabricate the reinforcing cage in sections. Use a crane to lift the reinforcing cage in sections, with the crane boom lifting at a low angle to ensure that the vertical distance between the top of the crane boom and the high-voltage line is greater than 6m. Then use a crane to connect the reinforcing cage sections and lower them into the pile hole until all the reinforcing cages are connected.

[0011] 6) Lower the guide pipe into the pile hole and perform secondary cleaning of the hole using the air-lift reverse circulation method through the guide pipe; after the secondary cleaning is completed, pour concrete into the pile hole through the side of the guide pipe until the concrete fills the pile hole, then detach the guide pipe from the pile hole, and the reinforcing cage and concrete form a pile in the pile hole.

[0012] Furthermore, in construction step 2), a vertical fence is set up on the side of the enclosure area away from the inner high-voltage projection area. A mud pit, a steel cage stacking area, a slag stacking area, and a temporary transportation channel are set up between the vertical fence and the enclosure area. High-voltage line safety construction warning signs are hung at intervals on the vertical fence.

[0013] Furthermore, the distance between the vertical enclosure and the inner high-pressure projection area is greater than or equal to 20m.

[0014] Furthermore, in construction step 2), both rows of lattice columns are evenly arranged along the pile location, and the distance between any two adjacent lattice columns in the two rows is 20m.

[0015] Furthermore, in construction step 2), the vertical distance between the top sealing net and the high-voltage line is greater than or equal to 6m.

[0016] Furthermore, in construction step 2), the distance between the two rows of lattice columns and the inner high-pressure projection area is greater than or equal to 6m.

[0017] Furthermore, in construction step 3), several warning poles in the vertical sealing net are erected at the minimum extension distance of the side line projection of the voltage conductors of each level within the power line protection zone, and the warning poles are evenly arranged along the pile location.

[0018] Furthermore, in construction step 3), the distance between every two adjacent warning poles in the vertical enclosure is 20m, the height of the warning pole is 4m, and the colored flags in the vertical enclosure are tied between several adjacent warning poles.

[0019] Furthermore, in construction step 2), the top enclosure is equipped with multiple first ranging radars for monitoring the approach of objects. The top enclosure includes four boundary lines located at the edge of the enclosure area. The four boundary lines enclose the top area of ​​the enclosure area. The multiple first ranging radars are arranged at intervals along the length of the boundary lines. The first ranging radars are electrically connected to a first loudspeaker, which is installed on the lattice column.

[0020] Multiple second ranging radars for detecting the approach of objects are installed on the vertical sealing net. The multiple second ranging radars are arranged at intervals along the length of the vertical sealing net. A second loudspeaker is electrically connected to the second ranging radar and is installed on the warning pole.

[0021] Furthermore, in construction step 3), the warning pole is provided with multiple wire-passing holes with external openings. The multiple wire-passing holes are arranged sequentially at intervals along the height direction of the warning pole. The wire-passing holes penetrate the warning pole laterally. A one-way swinging piece is provided on the external opening of the wire-passing hole, which swings toward the wire-passing hole. The top end of the one-way swinging piece is hinged to the external opening of the wire-passing hole, and the bottom end of the one-way swinging piece moves against the inner wall of the wire-passing hole so that the one-way swinging piece closes the external opening of the wire-passing hole.

[0022] A wire clamping mechanism is provided in the wire passage hole. The wire clamping mechanism includes two wire clamping heads that move up and down in opposite directions. The wire clamping heads are located in the wire passage hole. A rack that moves up and down is connected to the wire clamping head. The two racks are arranged laterally and are spaced apart from each other. The two racks are meshed with each other through a rotary drive shaft. One end of the rotary drive shaft is located in the warning bar, and the other end of the rotary drive shaft is exposed outside the warning bar and is equipped with a rotating cap.

[0023] Compared with existing technologies ， The present invention provides a safety protection construction method for low-headroom cast-in-place piles under high-voltage lines by setting up a top and vertical net. This method limits the height of machinery that may exceed the vertical net during construction and prohibits vehicles from leaving the vertical net, preventing contact with high-voltage lines. It also restricts machinery exceeding the net height from entering the netted area. Furthermore, the top and vertical nets, made of colorful flags, are clearly visible and serve as a good warning, avoiding significant economic losses and adverse social impacts caused by power outages due to electric shock. This method also ensures the safety of life and property on site and the normal construction process. In addition, the netting is safe, convenient, has low maintenance costs, is reusable, and has a low overall cost. Attached Figure Description

[0024] Figure 1This is a top view of the construction method for safety protection of low-headroom cast-in-place piles under high-voltage lines provided by the present invention.

[0025] Figure 2 This is the present invention. Figure 1 A schematic diagram of the side view section structure of AA;

[0026] Figure 3 This is the present invention. Figure 1 A schematic diagram of the side view section structure of BB;

[0027] Figure 4 This is a three-dimensional schematic diagram of the high-voltage line and the top sealing net provided by the present invention;

[0028] Figure 5 This is a three-dimensional schematic diagram of the high-voltage line and the vertical sealing net provided by the present invention;

[0029] Figure 6 This is a cross-sectional structural diagram of the warning rod and the wire hole provided by the present invention.

[0030] In the diagram: High-voltage line 10, High-voltage projection area 11, Inner high-voltage projection area 12, Outer high-voltage projection area 13, Construction site 20, Pile location 21, Top enclosure net 30, Grid column 31, First ranging radar 32, First loudspeaker 33, Vertical enclosure net 40, Warning pole 41, Wire hole 411, One-way swing plate 412, Wire clamp 413, Rack 414, Rotary drive shaft 415, Rotary cap 416, Second ranging radar 42, Second loudspeaker 43, Vertical fence 50, Enclosure net area 60. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0032] The implementation of the present invention will be described in detail below with reference to specific embodiments.

[0033] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this invention, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0034] Reference Figure 1-6 The image shown is a preferred embodiment of the present invention.

[0035] The construction method for power grid enclosure safety protection of 10 low-headroom cast-in-place piles under high-voltage lines includes the following construction steps:

[0036] 1) Level the construction site 20 on the foundation pit under the high voltage line 10. A power grid structure is set up on the construction site 20. The high voltage line 10 has a high voltage projection area 11 that is projected longitudinally onto the ground. The power grid structure includes a top grid 30 and a vertical grid 40.

[0037] 2) Reserve pile positions 21 on the construction site 20. Along the direction of the pile positions 21, pour column foundations on both sides of the pile positions 21 to form multiple lattice columns 31. The multiple lattice columns 31 are arranged in two rows on both sides of the pile positions 21. Pull height limit ropes and tie colored flags on the top of the lattice columns 31 to form a crisscrossing top netting 30. The top netting 30 and the construction site 20 are separated to form a netting area 60. The high-voltage projection area 11 includes the inner high-voltage projection area 1211 located within the netting area 60 and the outer high-voltage projection area 1311 located outside the netting area 60.

[0038] 3) A row of warning poles 41 is set up between the construction site 20 and the external high voltage projection area 1311, and colored flags are tied between adjacent warning poles 41 to form a vertical enclosure net 40;

[0039] 4) Drive the low-headroom rotary drilling rig to the sealed area 60, and use the low-headroom rotary drilling rig to rotary drill the pile position 21 in the sealed area 60 to form multiple pile holes. Use a slag bucket to clean the multiple pile holes once.

[0040] 5) Fabricate the steel cage in short sections. Use a crane to lift the steel cage in sections, with the crane boom lifting at a low angle to ensure that the vertical distance between the top of the crane boom and the high-voltage line 10 is greater than 6m. Then use a crane to connect the steel cage sections and lower them into the pile hole until all steel cages are connected.

[0041] 6) Lower the guide pipe into the pile hole and use the air-lift reverse circulation method to perform secondary cleaning of the hole through the guide pipe; after the secondary cleaning is completed, pour concrete into the pile hole through the side of the guide pipe until the concrete fills the pile hole. Then, the guide pipe is removed from the pile hole, and the reinforcing cage and concrete form a pile in the pile hole.

[0042] The aforementioned construction method for safety protection of low-headroom cast-in-place piles under high-voltage lines, through the setting of a top net 30 and a vertical net 40, can limit the height of machinery exceeding the vertical net during construction and prohibit vehicles from driving out of the vertical net 40, preventing contact with the high-voltage line 10. It also restricts machinery exceeding the net height from entering the netted area 60. Furthermore, the top net 30 and the vertical net 40, made of colored flags, are highly visible and serve as a good warning, avoiding significant economic losses and adverse social impacts caused by power outages due to electric shock. It also ensures the safety of life and property on site and the normal construction. Moreover, the net is safe, convenient, has low maintenance costs, can be reused, and has a low overall cost.

[0043] Pile position 21 is an interlocking pile position 21, and the height limit rope is an insulated Dyneema rope.

[0044] This construction method employs a low-clearance rotary drilling rig for bored pile drilling. By reducing the height of the drilling rig mast and configuring multi-section telescopic drill rods, the drilling height is reduced. The reinforcing cage for the bored pile is fabricated in short sections and connected on-site using straight threaded steel bars. During hoisting, the lifting height is reduced to meet height restrictions. During lifting operations, the lifting angle is limited, and the highest point of the boom is controlled to not exceed the vertical netting. During construction, personnel are arranged to patrol and inspect the site to promptly stop and correct any encroachment on the netting.

[0045] This construction method avoids significant economic losses and adverse social impacts caused by power outages due to electric shock, while also ensuring the safety of life and property on site and the normal construction process. Effective measures such as using low-clearance multi-section rotary drilling rigs, constructing steel cages in short sections, and low-angle hoisting are employed for construction within the power grid enclosure, ensuring project progress. The materials used to construct the power grid enclosure, such as the 31 lattice columns, Dyneema ropes, and colored flags, are economical, and the enclosure is easy to install, has low maintenance costs, and is reusable, resulting in overall cost-effectiveness.

[0046] In this embodiment, during construction step 2), a vertical fence 50 is installed on the side of the enclosure area 60 away from the inner high-voltage projection area 1211. Between the vertical fence 50 and the enclosure area 60, a mud pit, a rebar cage storage area, a slag storage area, and a temporary transport channel are provided. Safety warning signs for high-voltage line 10 are hung at intervals on the vertical fence 50. This strengthens safety control during the construction of the foundation pit support piles for the high-voltage line 10, ensures the safe operation of the high-voltage line 10, and achieves the effect of ensuring construction progress and economical overall cost.

[0047] In this embodiment, the distance between the vertical enclosure 50 and the inner high-voltage projection area 1211 is 20m. This allows the area between the vertical enclosure 50 and the netting area 60 to serve as a mud pit, a rebar cage storage area, a slag storage area, and a temporary transportation channel. It also provides certain warnings for large machinery and vehicles, restricting their entry into the vicinity of the high-voltage line 10, thus ensuring construction safety.

[0048] In this embodiment, in construction step 2), the two rows of lattice columns 31 are evenly arranged along the pile position 21. The spacing between any two adjacent lattice columns 31 in the two rows is 20m, and the height of the lattice column 31 is 12m. The height of the lattice column 31 limits the height of construction machinery within the influence range of the top sealing net 30 to no more than 12m, thereby ensuring a safe distance between the construction machinery and the high-voltage line 10.

[0049] Pile position 21 is the interlocking pile position 21.

[0050] In this embodiment, in construction step 2), the vertical distance between the top sealing net 30 and the high-voltage line 10 is 6m. This ensures a safe distance between construction machinery and equipment near the high-voltage line 10 and the edge of the overhead power line.

[0051] In construction step 2), the distance between the two rows of lattice columns 31 and the inner high-pressure projection area 1211 is 6m.

[0052] In this embodiment, during construction step 3), several warning poles 41 in the vertical sealing net 40 are erected 10m outside the high-pressure projection area 11, and the warning poles 41 are evenly arranged along the direction of the pile position 21.

[0053] In construction step 3), the distance between any two adjacent warning poles 41 in the vertical enclosure net 40 is 20m, the height of the warning pole 41 is 4m, and the colored flags in the vertical enclosure net 40 are tied between several adjacent warning poles 41.

[0054] It can restrict vehicles or machinery from leaving the vertical enclosure 40 to prevent them from touching the high-voltage line 10.

[0055] In this embodiment, in construction step 2), multiple first ranging radars 32 for monitoring the approach of objects are set in the top sealing net 30. The top sealing net 30 includes four boundary lines located at the edge of the sealing net area 60. The four boundary lines enclose the top area of ​​the sealing net area 60. Multiple first ranging radars 32 are arranged sequentially at intervals along the length direction of the boundary lines. A first loudspeaker 43 is electrically connected to the first ranging radar 32. The first loudspeaker 43 is installed on the lattice column 31.

[0056] Multiple second ranging radars 42 for detecting the approach of objects are installed on the vertical enclosure 40. The multiple second ranging radars 42 are arranged at intervals along the length of the vertical enclosure 40. A second loudspeaker 43 is electrically connected to the second ranging radar 42 and is installed on the warning pole 41.

[0057] The top enclosure 30 monitors machinery approaching the top enclosure 30 via the first ranging radar 32. When the height of the machinery approaches the top enclosure 30 to a certain range, the first ranging radar 32 sounds an alarm via the first loudspeaker 33 and plays the distance between the machinery and the edge of the top enclosure 30, so that on-site personnel can make a judgment.

[0058] The vertical enclosure 40 monitors machinery approaching the vertical enclosure 40 via the second ranging radar 42. When the machinery approaches the vertical enclosure 40 to a certain range, the second ranging radar 42 issues an alarm via the second loudspeaker 43 and broadcasts the distance between the machinery and the vertical enclosure 40, so that on-site personnel can make a judgment.

[0059] In this embodiment, in construction step 3), the warning rod 41 is provided with multiple wire holes 411 with external openings. The multiple wire holes 411 are arranged sequentially at intervals along the height direction of the warning rod 41. The wire holes 411 pass through the warning rod 41 laterally. A one-way swing piece 412 is provided on the external opening of the wire hole 411 and swings toward the inside of the wire hole 411. The top end of the one-way swing piece 412 is hinged to the external opening of the wire hole 411, and the bottom end of the one-way swing piece 412 moves to abut against the inner sidewall of the wire hole 411 so that the one-way swing piece 412 closes the external opening of the wire hole 411.

[0060] A wire clamping mechanism is provided in the wire hole 411. The wire clamping mechanism includes two wire clamping heads 413 that move up and down in opposite directions. The wire clamping heads 413 are located in the wire hole 411. A rack 414 that moves up and down is connected to the wire clamping heads 413. The two racks 414 are arranged laterally opposite to each other. The two racks 414 are meshed with each other through a rotary drive shaft 415. One end of the rotary drive shaft 415 is located in the warning bar 41, and the other end of the rotary drive shaft 415 is exposed outside the warning bar 41 and is equipped with a rotating cap 416.

[0061] The warning pole 41 allows the colored flag to pass through the wire hole 411. The wire hole 411 uses a one-way swing plate 412 to prevent the colored flag from falling out of the wire hole 411 at will. By manually rotating the rotating cap 416, the rotating cap 416 drives the rotating drive shaft 415 to move the two racks 414 towards each other, thereby causing the two wire clamps 413 to clamp and fix the colored flag. This makes it easy to fix and limit the colored flag, so that the colored flag can be quickly tied to the warning pole 41.

[0062] The scope of application of this construction method is as follows: it is applicable to the construction of low-headroom cast-in-place piles under high-voltage lines with a vertical distance of 16 to 18m from the ground; and it is applicable to the construction of low-headroom rotary cast-in-place piles with a diameter of no more than 1500mm and a hole depth of no more than 30m.

[0063] Taking the "Shahe Water Purification Plant and No. 3 Regulating Reservoir Supporting Project" as an example, this construction method solves the technical and safety control problems of low-headroom cast-in-place pile construction under high-voltage lines by setting up a 20-level safety control zone at the construction site, selecting the best construction machinery, and optimizing the construction process. Key technologies include power grid sealing for safe construction under high-voltage lines and low-headroom cast-in-place pile drilling and pile forming technology.

[0064] The 110KV high-voltage line 10 on the north side of the project intersects obliquely with the foundation pit support pile 21. The lowest point of the high-voltage line 10 is 18m from the ground. The safety control distance between the construction machinery and equipment near the high-voltage line 10 and the edge of the overhead power line is designed as "minimum safety control distance + additional safety control distance", that is, the safety control distance in both the vertical and horizontal directions is not less than 6m. A safety warning line is set up 10m outside the high-voltage projection area 11.

[0065] I. Site leveling and stake marking 21

[0066] 1) Before construction, remove surface debris from the site under the high-voltage line 10, use a road roller to level and compact the site, and use a total station to measure the vertical distance between the lowest point of the high-voltage line 10 and the ground.

[0067] 2) Based on the coordinates provided in the design drawings and the ground conductor control points, mark the pile position 21 axis with steel bars and lime, which will serve as the control centerline for the construction of the interlocking pile guide wall and the position reference line for the construction of the power grid under the high-voltage line 10.

[0068] II. Protective Design of the Power Grid Structure Below High-Voltage Line 10

[0069] 1) According to relevant regulations, the safety control distance between construction machinery and equipment near the high-voltage line 10 and the edge of the overhead power line must meet the requirement that the vertical and horizontal safety control distances are not less than 6m, and a warning line shall be set up at a location 10m outside the high-voltage projection area 11.

[0070] 2) To ensure the normal operation of high-voltage line 10 and the normal construction of pile foundation, a top sealing net 30 with a height limit of 12m is installed above pile position 21 within a 6m extension of the high-voltage projection area 11, along the direction of pile position 21; at the same time, a vertical sealing net 40 with a height limit of 12m is installed in the area 10m extension of the high-voltage projection area 11, and a high-voltage line 10 safety construction warning sign is hung.

[0071] 3) Based on relevant regulations, standards and engineering characteristics, prepare a special construction plan for the power grid closure of the 10 high-voltage lines and submit it to the power management department for approval.

[0072] III. Measurement and layout of the netting posts and foundation excavation

[0073] 1) After the power management department approves the construction plan for the power grid enclosure under the high-voltage line 10, the center line of the foundation of the grid column 31 is measured and marked on both sides of the pile position 21.

[0074] 2) On the northwest side of the site, due to the small distance between the construction site wall and pile position 21, the center line of the column foundation is measured and laid out on both sides of pile position 21, extending 1.5m outward from the high-voltage projection area 11 on the side close to the wall and extending 6m outward from the high-voltage projection area 11 on the side close to the site.

[0075] 3) After the center of the column foundation is laid out, 1:1 slope excavation is carried out; when the excavator is excavating, a 20-30cm soil layer is reserved at the bottom of the trench and then manually excavated to the design elevation.

[0076] IV. Column Foundation Casting and Installation

[0077] 1) After excavating the foundation pit for lattice column 31, the foundation steel reinforcement cage is tied, and the bottom of the first lattice column 31 is fixed to the foundation steel reinforcement cage. Formwork is erected around the perimeter. Subsequently, the reinforced concrete foundation is poured in layers and vibrated evenly using an immersion vibrator.

[0078] 2) After the column foundation is inspected and accepted, the next lattice column 31 is vertically hoisted to the top of the first lattice column 31. The two lattice columns 31 are connected by bolts and connected section by section to form a 12m high column. One column is erected every 20m and arranged in two rows on both sides of the pile position 21.

[0079] 5. Install a 30mm top sealing net under the high-voltage line 10.

[0080] 1) After the columns are installed, professionals will board the XCMG GKS26 aerial work platform, raise and move to the top of the column to tie insulated Dyneema ropes. Connect the two rows of columns in the east-west direction, and tie vertical Dyneema ropes evenly at 4m intervals along the direction perpendicular to the lattice column 31. Then tie another Dyneema rope between the two rows of lattice columns 31 and connect and fix it to each vertical Dyneema rope. Finally, tie colored flags to each Dyneema rope.

[0081] 2) The top netting 30 is 6m perpendicular to the high-voltage line 10 and extends 6m beyond the high-voltage side conductor; the top netting 30 has a line protection effect, and it is strictly forbidden for any machinery in the netting area 60 to exceed the vertically set netting.

[0082] VI. Install horizontal protective netting outside the projection of the high-voltage line 10.

[0083] 1) To facilitate the construction of interlocking piles on the northwest side of the site, a row of vertical fences 50 is set up about 20m outside the inner high-voltage projection area 1211 on the side closest to the site. Between the netted area 60 and the vertical fences 50, a mud pit, a steel cage storage area, a slag storage area, and a temporary transportation channel are set up. High-voltage line 10 safety construction warning signs are hung at intervals on the vertical fences 50 to prevent large machinery and vehicles from entering the vicinity of the high-voltage line 10.

[0084] 2) Since the distance between the interlocking pile position 21 on the northeast side of the site and the external high voltage projection area 1311 on the side close to the site is less than 10m, a row of warning poles 41 with a height of 4m and a spacing of 20m is installed near the pile position 21 on the side close to the high voltage line. Colored flags are tied between the warning poles 41 to form a vertical enclosure net 40. Large machinery and vehicles exceeding the height of the top enclosure net 30 are prohibited from driving out of the vertical enclosure net 40 to prevent them from touching the high voltage line 10.

[0085] 3) After the power grid closure construction is completed and the power department approves the work, the low-headroom cast-in-place pile construction will proceed.

[0086] VII. Low-headroom rotary drilling rig in place

[0087] 1) After the power grid is installed, a guide wall is constructed. The guide wall is designed to be 3.75m wide and 50cm thick. Manual labor and machinery are used to excavate the guide wall trench, pour the foundation layer, and mark the axis of the guide trench.

[0088] 2) Tie the guide channel reinforcement according to the design drawings, fix the steel formwork, and pour concrete symmetrically and alternately on both sides to complete the construction of the guide wall. After the guide wall is built, the low headroom rotary drilling rig is placed in position, leveled, centered and placed stably.

[0089] 8. Low headroom multi-section rotary drilling rig for hole formation

[0090] 1) The interlocking piles are drilled by rotary drilling rigs. The diameter of plain concrete piles is 1.2m, the diameter of reinforced concrete piles is 1.4m, and the average pile length is about 24m.

[0091] 2) The rotary drilling rigs used are the XCMG XR360 modified low headroom rotary drilling rig and the Sunward Intelligent 300HL low headroom rotary drilling rig. The XCMG XR360 low headroom rotary drilling rig has a maximum output torque of 360kN·m, a mast height of 7.66m, and is equipped with 5 drill rods, each 6m long; the Sunward Intelligent 300HL low headroom rotary drilling rig is 11.5m high, has a maximum output torque of 320kN·m, and a maximum drilling depth of 43m.

[0092] 3) To prevent borehole collapse during construction, a 3m steel casing is installed when constructing plain piles; the upper soil layer is drilled from inside the casing using a rotary drilling bucket, and when entering hard rock, a rotary drilling bucket is used for cutting and drilling.

[0093] 4) When constructing the concrete pile, mud slurry should be used for wall protection during drilling, and the mud slurry level should be controlled to be more than 0.5m above the groundwater level. At the same time, attention should be paid to strictly controlling the drilling speed of the rotary drilling rig cutting plain concrete to 12-15 r / min.

[0094] 5) Under power grid closure, low-headroom rotary drilling rigs drill holes using telescopic short drill rods. Drill cuttings removed from the drill barrel are directly piled at designated locations beside the pile hole, promptly cleaned up and stacked at designated locations, and then transported away in a centralized manner.

[0095] 6) After drilling to the design elevation, use a slag bucket to clean the hole once; after cleaning the hole, move the drilling rig away from the pile hole and check the hole depth, hole diameter, verticality, etc.

[0096] 9. Low-angle, sectional lifting of steel cages using a truck crane

[0097] 1) The average length of the steel reinforcement cage for the hoisting pile is 24m. The steel reinforcement cage is made into short sections, with a total of 4 sections, each about 6m long, to ensure that the highest point of the hoisting machinery is less than the safety height limit during hoisting.

[0098] 2) The ZOOMLION QY25H truck crane was used for the sectional hoisting of the steel cage. The crane boom was lifted at a low angle to ensure that the vertical distance between its top and the high-voltage line 10 was greater than 6m.

[0099] 3) During hoisting, first place the upper section of the steel cage through the steel section and temporarily support it on the guide wall, then lift the lower section of the steel cage to the top of the hole, so that the upper and lower sections of the steel cage are on the same straight line, and then connect the straight threaded sleeve at the hole. After all the joints are connected, wrap the stirrups and put it into the hole until all the steel cages are connected.

[0100] 10. Low-angle placement of the infusion catheter and secondary cleaning of the borehole.

[0101] 1) The interlocking piles are poured using the underwater concrete pouring method. The guide pipe is a steel pipe with an inner diameter of 300mm and a wall thickness of 4mm. Each standard section is 3m long.

[0102] 2) Using a Zoomlion ZCT300V5 truck crane, lift the single sections of guide pipe sequentially to the borehole opening at a low angle, connect each section at the borehole opening, and lower them to a position 30-50cm from the bottom of the pile hole.

[0103] 3) Before pouring concrete, measure the thickness of the sediment at the bottom of the pile hole. If it exceeds the design requirements, use the air-lift reverse circulation method to clean the hole a second time. Use high-quality mud to replace and remove the sediment at the bottom of the hole.

[0104] XI. Low-headroom concrete pouring

[0105] 1) After the secondary hole cleaning meets the requirements, the truck crane raises the boom at a low angle and lifts the grouting hopper to the top of the guide pipe for grouting platform installation.

[0106] 2) When pouring concrete, measure the height of the concrete surface in the hole regularly and control the buried pipe depth to 2-4m; after pouring, when disassembling the pouring hopper and guide pipe, and during the process of lifting the steel casing, strictly prevent the lifting machinery from exceeding the sealing net.

[0107] The above description is based on a technical solution using a 110kV high-voltage line as the standard. The horizontal and vertical safety control distances of the high-voltage line can be adjusted according to the actual safe distance of the kV high-voltage line.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A construction method for safety protection of power grid enclosure for low-headroom cast-in-place piles under high-voltage lines, characterized in that, The construction steps include the following: 1) Level the construction site at the foundation pit location under the high voltage line. A power grid structure is set up on the construction site. The high voltage line has a high voltage projection area projected longitudinally onto the ground. The power grid structure includes a top grid and a vertical grid. 2) Reserve pile positions on the construction site, and pour column foundations on both sides of the pile positions to form multiple lattice columns along the direction of the pile positions. The multiple lattice columns are arranged in two rows on both sides of the pile positions. Stretch height limit ropes and tie colored flags on the top of the lattice columns to form a crisscrossing top sealing net. The top sealing net is separated from the construction site to form a sealing net area. The high-voltage projection area includes an inner high-voltage projection area located within the sealing net area and an outer high-voltage projection area located outside the sealing net area. 3) A row of warning poles is set up between the construction site and the external high-voltage projection area, and colored flags are tied between adjacent warning poles to form the vertical enclosure net; 4) Drive the low-headroom rotary drilling rig into the sealed area, and use the low-headroom rotary drilling rig to rotary drill the pile positions in the sealed area to form multiple pile holes. Use a slag hopper to clean the multiple pile holes once. 5) Fabricate the reinforcing cage in sections. Use a crane to lift the reinforcing cage in sections, with the crane boom lifting at a low angle to ensure that the vertical distance between the top of the crane boom and the high-voltage line is greater than 6m. Then use the crane to connect the reinforcing cage sections and lower them into the pile hole until all the reinforcing cages are connected. 6) Lower the guide pipe into the pile hole and perform secondary cleaning of the hole using the air-lift reverse circulation method through the guide pipe; after the secondary cleaning is completed, pour concrete into the pile hole through the side of the guide pipe until the concrete fills the pile hole, then detach the guide pipe from the pile hole, and the reinforcing cage and concrete form a pile in the pile hole. In construction step 2), the top enclosure is equipped with multiple first ranging radars for monitoring the approach of objects. The top enclosure includes four boundary lines located at the edge of the enclosure area. The four boundary lines enclose the top area of ​​the enclosure area. The multiple first ranging radars are arranged at intervals along the length of the boundary lines. The first ranging radars are electrically connected to a first loudspeaker alarm, which is installed on the lattice column. Multiple second ranging radars for detecting the approach of objects are installed on the vertical sealing net. The multiple second ranging radars are arranged at intervals along the length of the vertical sealing net. A second loudspeaker is electrically connected to the second ranging radar and is installed on the warning pole.

2. The construction method for safety protection of power grid enclosure for low-headroom cast-in-place piles under high-voltage lines as described in claim 1, characterized in that, In construction step 2), a vertical fence is set up on the side of the enclosure area away from the inner high-voltage projection area. A mud pit, a steel cage storage area, a slag storage area, and a temporary transportation channel are set up between the vertical fence and the enclosure area. High-voltage line safety construction warning signs are hung at intervals on the vertical fence.

3. The construction method for safety protection of power grid sealing of low-headroom cast-in-place piles under high-voltage lines as described in claim 2, characterized in that, The distance between the vertical enclosure and the inner high-pressure projection area is greater than or equal to 20m.

4. The construction method for safety protection of power grid enclosure for low-headroom cast-in-place piles under high-voltage lines as described in claim 3, characterized in that, In construction step 2), the two rows of lattice columns are evenly arranged along the pile location, and the distance between any two adjacent lattice columns in the two rows is 20m.

5. The construction method for safety protection of power grid enclosure for low-headroom cast-in-place piles under high-voltage lines as described in claim 4, characterized in that, In construction step 2), the vertical distance between the top sealing net and the high-voltage line is greater than or equal to 6m.

6. The construction method for safety protection of power grid enclosure for low-headroom cast-in-place piles under high-voltage lines as described in claim 4, characterized in that, In construction step 2), the distance between the two rows of lattice columns and the inner high-pressure projection area is greater than or equal to 6m.

7. The construction method for safety protection of power grid enclosure for low-headroom cast-in-place piles under high-voltage lines as described in any one of claims 1 to 6, characterized in that, In construction step 3), several warning poles in the vertical sealing net are erected at the minimum extension distance of the side line projection of the voltage conductors of each level within the power line protection zone, and the warning poles are evenly arranged along the pile position.

8. The construction method for safety protection of power grid sealing of low-headroom cast-in-place piles under high-voltage lines as described in claim 7, characterized in that, In construction step 3), the distance between any two adjacent warning poles in the vertical enclosure is 20m, the height of the warning pole is 4m, and the colored flags in the vertical enclosure are tied between several adjacent warning poles.

9. The construction method for safety protection of power grid enclosure for low-headroom cast-in-place piles under high-voltage lines as described in claim 8, characterized in that, In construction step 3), the warning pole is provided with multiple wire-passing holes with external openings. The multiple wire-passing holes are arranged sequentially at intervals along the height direction of the warning pole. The wire-passing holes penetrate the warning pole laterally. A one-way swinging piece is provided on the external opening of the wire-passing hole, which swings toward the wire-passing hole. The top end of the one-way swinging piece is hinged to the external opening of the wire-passing hole, and the bottom end of the one-way swinging piece moves against the inner wall of the wire-passing hole so that the one-way swinging piece closes the external opening of the wire-passing hole. A wire clamping mechanism is provided in the wire passage hole. The wire clamping mechanism includes two wire clamping heads that move up and down in opposite directions. The wire clamping heads are located in the wire passage hole. A rack that moves up and down is connected to the wire clamping head. The two racks are arranged laterally and are spaced apart from each other. The two racks are meshed with each other through a rotary drive shaft. One end of the rotary drive shaft is located in the warning bar, and the other end of the rotary drive shaft is exposed outside the warning bar and is equipped with a rotating cap.

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