A rock anchor foundation for reducing soil erosion of a power transmission line and its construction method

Abstract

A rock anchor foundation for reducing soil erosion of a power transmission line and a construction method thereof, the rock anchor foundation comprises a foundation cap, the foundation cap is composed of a cap body, a cap retaining wall and a drainage pipe arranged on the side of the upper surface of the cap body; the drainage pipe is arranged at the root of the cap retaining wall, and the drainage pipe can discharge the accumulated water on the upper surface of the cap body to the outside of the cap body; a cap column is arranged on the upper surface of the cap body, and a plurality of foundation anchors are arranged on the lower surface of the cap body; the foundation anchor is vertically inserted into the slope surface, the cap body remains horizontal, the cap column remains vertical, and the cap retaining wall is located at two adjacent sides of the upper surface of the cap body at a lower terrain. The present invention solves the serious soil erosion problem faced by the rock anchor foundation when it is used in a tower position with steep terrain and thick covering layer by optimizing the rock anchor foundation structure, and the foundation increases the safety of the foundation, providing a guarantee for the safe and reliable operation of the power transmission line.

Description

Technical Field

[0001] The invention relates to the technical field of power transmission line foundations, and in particular to a rock anchor foundation for reducing soil and water loss in a power transmission line and a construction method thereof. Background Art

[0002] For transmission towers in mountainous areas, traditional hole-digging foundations are usually used. The mechanized construction requirements of hole-digging foundations are high, and manual excavation is often required when necessary. The excavation is very difficult, and sometimes blasting is required to excavate the foundation pit, which not only damages the mountainous environment, but also has a high construction risk. The rock anchor foundation is an anchor foundation formed by pouring cement mortar into the drilled rock hole and using ordinary steel as the anchor body. The anchor is connected to the tower through a cap, and the bottom of the cap is placed on Class IV rock mass and embedded in the bedrock more than 0.5m. The rock anchor foundation can give full play to the mechanical properties of the original rock mass, provide good pull-out resistance, and has a high mechanized construction rate, good economic and environmental benefits. Therefore, it is gradually being promoted and applied to the tower foundation of overhead transmission lines.

[0003] As the engineering experience becomes richer, the use conditions of rock anchor foundation are gradually relaxed. Some projects use it in towers with steep terrain and thick cover. When it is exposed to rain, such towers will suffer from soil erosion due to the large excavation depth and unstable backfill soil. This makes the rock anchor foundation have some shortcomings during use, increasing the risk of soil erosion. Summary of the invention

[0004] The purpose of the present invention is to provide a rock anchor foundation for reducing soil erosion of a power transmission line and a construction method thereof, so as to improve the stability of backfill soil and prevent soil erosion.

[0005] In order to achieve the above object, the present invention has the following technical solutions:

[0006] A rock anchor foundation for reducing soil erosion of a power transmission line comprises a foundation cap, which is composed of a cap body, a cap retaining wall and a drainage pipe arranged on the side of the upper surface of the cap body; the drainage pipe is arranged at the root of the cap retaining wall, and the drainage pipe can drain the accumulated water on the upper surface of the cap body to the outside of the cap body; cap columns are arranged on the upper surface of the cap body, and a plurality of foundation anchors are arranged on the lower surface of the cap body; the foundation anchors are vertically inserted into the slope surface, the cap body remains horizontal, the cap columns remain vertical, and the cap retaining wall is located on two adjacent sides of the upper surface of the cap body at a lower terrain.

[0007] As a preferred solution of the rock anchor foundation of the present invention, the cap body, cap columns and cap retaining wall are cast in one piece.

[0008] As a preferred solution of the rock anchor foundation of the present invention, a plurality of drainage pipes are arranged at equal intervals at the root of the cap retaining wall.

[0009] As a preferred solution of the rock anchor foundation of the present invention, the foundation anchors are evenly arranged on the lower surface of the pedestal body, and the distance between the foundation anchors is 3 to 4 times the diameter of the foundation anchors; the length of the foundation anchors is 3m to 8m.

[0010] As a preferred solution for the rock anchor foundation of the present invention, the foundation anchor is made of C30 fine stone concrete with a fine stone particle size of 5mm~8mm. An expansion agent is added to the C30 fine stone concrete, and the 14d limited expansion rate in the concrete water is greater than 0.02%. The addition amount is 6%-8% of the cement dosage.

[0011] As a preferred solution of the rock anchor foundation of the present invention, main column reinforcement is arranged inside the cap column, and the main column reinforcement includes main column main reinforcement and main column stirrups; the main column main reinforcement is arranged vertically around and extends to the bottom surface of the cap body, the main column main reinforcement and the main column stirrups are tied or welded together, the main column stirrups are evenly arranged along the main column main reinforcement, and a main column stirrup is added at the cross-section change point of the cap column and 100mm above and below;

[0012] The main reinforcement of the main column is made of HRB400 grade steel bars, and the stirrups of the main column are made of HPB300 grade steel bars.

[0013] As a preferred solution of the rock anchor foundation of the present invention, a cap steel bar is arranged inside the foundation cap, and the cap steel bar includes an upper main bar, a lower main bar, a cap stirrup and a cap tie bar. The upper main bar and the lower main bar are arranged on the upper and lower surface bodies of the cap body and the cap retaining wall. A plurality of cap stirrups are arranged at intervals in the height direction, and the cap tie bars are connected between the upper main bar and the lower main bar.

[0014] The upper main reinforcement and the lower main reinforcement are made of HRB400 grade steel bars, and the remaining foundation reinforcements are made of HPB300 grade steel bars.

[0015] As a preferred solution of the rock anchor foundation of the present invention, anchor reinforcement bars are arranged inside the foundation anchor, and the anchor reinforcement bars include main anchor bars, end anchor bars and centering reinforcement bars. The main anchor bars extend into the interior of the pedestal body, and one end located inside the pedestal body is double-sidedly welded to the two end anchor bars; the centering reinforcement bars are used to fix the main anchor bars in the anchor hole, are trapezoidal, and both ends extend outwardly and are welded to the main anchor bars. Several of them are evenly arranged along the circumference of the same height of the main anchor bars to form a group, and a group of centering reinforcement bars is arranged every 2000 mm from 350 mm below the hole mouth;

[0016] The main anchor bars and end anchor bars are made of HRB400 grade steel bars, and the centering steel bars are made of HPB300 grade steel bars.

[0017] As a preferred solution of the rock anchor foundation of the present invention, the top surface of the cap column is provided with anchor bolts and concrete protective caps;

[0018] The anchor bolts are made of Q235 steel, No. 35 steel or 42CrMo steel;

[0019] The concrete protective cap is made of C15 plain concrete.

[0020] The present invention also provides a rock anchor foundation construction method for reducing soil erosion of a power transmission line, comprising the following steps:

[0021] The foundation cap foundation pit is excavated to form the foundation cap foundation pit;

[0022] Drilling and cleaning of foundation anchor holes;

[0023] Anchor reinforcement insertion;

[0024] Concrete pouring, compacting and curing of foundation anchors;

[0025] Process the main column steel bars and the cap steel bars, and fix the anchor bolts on the main column steel bars;

[0026] Place the cap steel bars into the cap foundation pit;

[0027] Pour the cap columns and foundation cap with concrete on the main column reinforcement and cap reinforcement;

[0028] After the pole tower and wire rack are installed, tighten the anchor bolts again and finally pour concrete protective caps on the anchor bolts.

[0029] Compared with the prior art, the present invention has at least the following beneficial effects: the rock anchor foundation is suitable for slope surfaces and can reduce soil erosion. By vertically inserting the foundation anchor into the slope surface, the main body of the pedestal is kept horizontal. The pedestal columns are arranged on the upper surface of the main body of the pedestal, and the pedestal columns can be kept vertical. A pedestal retaining wall and a drainage pipe are arranged on the side of the upper surface of the main body of the pedestal, wherein the pedestal retaining wall is located at two adjacent sides of the upper surface of the main body of the pedestal at a lower terrain, and the drainage pipe is arranged at the root of the pedestal retaining wall. The water accumulated on the upper surface of the main body of the pedestal can be drained to the outside of the main body of the pedestal through the drainage pipe. By optimizing the rock anchor foundation structure, the serious soil erosion problem faced by the rock anchor foundation when it is used in a steep terrain and a thick covering layer is solved. In addition, the rock anchor foundation rationally utilizes the terrain conditions, reasonably distributes the deadweight of the soil above the pedestal, and increases the safety of the foundation. The present invention has a simple and reasonable structure, is safe and reliable, is easy to construct, easy to operate, pays attention to environmental protection, and saves investment, thereby expanding the scope of application of the rock anchor foundation, reducing the proportion of manpower, reducing safety risks, improving work efficiency, ensuring personnel safety, and contributing to the construction of a resource-saving and environmentally friendly line. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0031] Figure 1 A schematic cross-sectional structure diagram of a rock bolt foundation of the present invention;

[0032] Figure 2 A schematic diagram of the top view of the rock bolt foundation of the present invention;

[0033] Figure 3 Schematic diagram of the internal steel bar structure of the rock bolt foundation of the present invention;

[0034] Figure 4 A schematic front view of the structure of the anchor bar of the present invention;

[0035] Figure 5 A schematic top view of the connection structure between the main anchor bar and the end anchor bar in the anchor bar of the present invention;

[0036] Figure 6 A schematic top view of the connection structure between the main anchor bar and the centering steel bar in the anchor bar of the present invention;

[0037] In the attached figure: 1-cap pedestal column; 2-foundation cap; 3-foundation anchor rod; 4-anchor bolt; 5-concrete protective cap; 2-1. Cap body; 2-2. Cap retaining wall; 2-3. Drain pipe; 13-anchor rod steel bar; 11-1. Main column main bar; 11-2. Main column stirrups; 12-1. Upper main bar; 12-2. Lower main bar; 12-3. Cap stirrups; 12-4. Cap tension bar; 13-1. Main anchor bar; 13-2. End anchor bar; 13-3. Centering steel bar. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0039] See also Figure 1 The rock anchor foundation for reducing soil erosion of a power transmission line proposed by the present invention comprises the following three parts:

[0040] (1) Foundation concrete part;

[0041] The foundation concrete part includes, from top to bottom, the cap column 1, the foundation cap 2 and the foundation anchor rod 3.

[0042] 1.1. The foundation support column 1 can be a round column or a square column.

[0043] The cap column 1 and the underlying base cap 2 are integrally formed by casting.

[0044] The foundation column 1 is made of C30 concrete, and the net protective layer of the steel bars is 60mm.

[0045] 1.2. The foundation pedestal 2 includes a pedestal body 2-1, a pedestal retaining wall 2-2 and a drainage pipe 2-3.

[0046] See also Figure 2 The supporting platform body 2-1 is a rectangular parallelepiped structure with equal length and width.

[0047] The cap retaining wall 2-2 is arranged along two sides of the cap body 2-1 and is cast integrally with the cap body 2-1.

[0048] In order to ensure the stability of the soil above the foundation pedestal 2 and smooth drainage, a number of drainage pipes 2-3 are provided at the root of the pedestal retaining wall 2-2. The drainage pipes 2-3 are arranged at equal intervals, fixed when the pedestal reinforcement is tied, and cast integrally with the pedestal body 2-1 and the pedestal retaining wall 2-2.

[0049] Drain pipe 2-3 is made of UPVC material and has a diameter of 50mm.

[0050] The foundation pedestal 2 should be made of C30 concrete, and the net protective layer of the steel bars should be 60mm.

[0051] The foundation pedestal 2 should be embedded in Class IV bedrock, and the embedding depth should not be less than 0.5m.

[0052] 1.3. The foundation anchor rods 3 are evenly distributed below the foundation pedestal 2, and the distance between the anchor rods should be 3 to 4 times the diameter of the anchor rods.

[0053] The length of foundation anchor rod 3 should be 3m~8m.

[0054] The foundation anchor 3 should use C30 fine stone concrete, the fine stone particle size should be 5~8mm, and the sand should be medium sand.

[0055] Fine stone concrete should be added with an appropriate amount of expansive agent. After adding the expansive agent, the concrete strength should still reach the design strength. The 14d limited expansion rate of concrete in water should be greater than 0.02%. The recommended dosage is 6%-8% of the cement dosage.

[0056] (2) Foundation reinforcement part;

[0057] See also Figure 3 The foundation reinforcement from top to bottom is the main column reinforcement, the pedestal reinforcement and the anchor reinforcement 13.

[0058] The main column reinforcement includes main column main reinforcement 11-1 and main column stirrups 11-2.

[0059] Furthermore, the main column main reinforcement 11-1 is arranged vertically around the main column and extends to the bottom surface of the pedestal. The main column main reinforcement 11-1 is tied or welded together with the main column stirrups 11-2. The main column stirrups 11-2 are evenly arranged along the main column main reinforcement 11-1, and a main column stirrup 11-2 is added at the main column cross-section change point and 100mm above and below.

[0060] The main column main reinforcement 11-1 adopts HRB400 grade steel bars, and the main column stirrups 11-2 adopt HPB300 grade steel bars.

[0061] The cap reinforcement includes upper main reinforcement 12-1, lower main reinforcement 12-2, cap stirrups 12-3, and cap tie bars 12-4. The upper main reinforcement 12-1 and lower main reinforcement 12-2 are made of HRB400 grade steel bars, and the remaining cap reinforcements are made of HPB300 grade steel bars.

[0062] See also Figure 4 The anchor reinforcement 13 includes a main anchor reinforcement 13-1, an end anchor reinforcement 13-2 and a center reinforcement 13-3.

[0063] Furthermore, the main anchor bar 13-1 extends to the interior of the pedestal and is double-sidedly welded to the two end anchor bars 13-2 at the pedestal end, thereby reducing the anchoring length of the main anchor bar 13-1. Figure 5 shown.

[0064] The end anchor bar 13-2 is made of the same material and has the same diameter as the main anchor bar 13-1, and its length is three times the diameter of the main anchor bar 13-1.

[0065] Furthermore, the centering steel bar 13-3 is used to fix the main anchor bar 13-1 in the anchor hole. It is trapezoidal and its two ends extend outward to be welded to the main anchor bar 13-1. Three centering steel bars 13-3 are evenly arranged along the circumference of the same height of the main anchor bar 13-1 to form a group. Each group of three centering steel bars 13-3 is evenly distributed at 120°. The centering steel bars 13-3 are arranged in a group every 2000mm from 350mm below the hole. Figure 6 shown.

[0066] The main anchor bars 13-1 and the end anchor bars 13-2 are made of HRB400 grade steel bars, and the centering bars 13-3 are made of HPB300 grade steel bars.

[0067] (3) Anchor bolts and protective caps;

[0068] The anchor bolt 4 is made of Q235 steel, No. 35 steel or 42CrMo steel.

[0069] Rock anchor foundations should be avoided at corrosive tower locations in overhead transmission lines, and C15 plain concrete should be used for the concrete protective cap 5.

[0070] An embodiment of a rock anchor foundation construction method for reducing soil erosion of a power transmission line of the present invention comprises the following steps:

[0071] S1. Select a drilling rig according to the size of the foundation anchor 3 and process the anchor.

[0072] S2. Excavate the foundation pit of foundation bearing platform 2 and clean the base surface.

[0073] S3. Assemble the drilling rig and align the drilling frame.

[0074] S4. Drilling and cleaning of foundation anchor rod 3. During the drilling process, the verticality of the drilling rig, the water injection loss, and the geological and underground conditions should be monitored.

[0075] S5. Acceptance of anchor holes of foundation anchor rod 3.

[0076] S6. Drilling rig evacuation.

[0077] S7. Anchor reinforcement 13 is inserted.

[0078] S8. Concrete pouring and compacting of foundation anchor 3 and preparation of concrete test blocks.

[0079] S9. Concrete maintenance of foundation anchor 3.

[0080] S10. Quality acceptance of foundation anchor 3.

[0081] S11. Process the main column reinforcement and the cap reinforcement according to the size of the foundation reinforcement, and fix the anchor bolts 4 on the main column reinforcement according to the designed position.

[0082] S12. Place the foundation steel bars into the foundation pit.

[0083] S13. Use C30 concrete to pour the pedestal column 1 and the foundation pedestal 2. The pouring process should be continuous and uninterrupted.

[0084] S14, maintaining the pedestal column 1 and the foundation pedestal 2.

[0085] S15. Carry out quality inspection on the pedestal column 1 and foundation pedestal 2.

[0086] S16, pole tower and line installation.

[0087] S17. After the pole tower and the wires are all installed, tighten the anchor bolts 4 again, and cast concrete protective caps 5 on the anchor bolts 4 with C15 plain concrete.

[0088] The present invention has been described above in conjunction with specific features and embodiments thereof. It is obvious that various modifications and combinations may be made thereto without departing from the spirit and scope of the present invention. Accordingly, this specification and the accompanying drawings are merely exemplary illustrations of the present invention as defined by the appended claims, and are deemed to have covered any and all modifications, variations, combinations or equivalents within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention, and these modifications and modifications also fall within the scope of the claims of the present invention and their equivalents.

Claims

1. A rock anchor foundation for reducing soil erosion of a power transmission line, characterized by: The invention comprises a foundation pedestal (2), wherein the foundation pedestal (2) comprises a pedestal body (2-1), a pedestal retaining wall (2-2) and a drainage pipe (2-3) arranged on the side of the upper surface of the pedestal body (2-1); the drainage pipe (2-3) is arranged at the root of the pedestal retaining wall (2-2), and the drainage pipe (2-3) can drain the accumulated water on the upper surface of the pedestal body (2-1) to the outside of the pedestal body (2-1); a pedestal column (1) is arranged on the upper surface of the pedestal body (2-1), and a plurality of foundation anchor rods (3) are arranged on the lower surface of the pedestal body (2-1); the foundation anchor rods (3) are vertically inserted into the slope surface, the pedestal body (2-1) is kept horizontal, the pedestal column (1) is kept vertical, and the pedestal retaining wall (2-2) is located at two adjacent sides of the upper surface of the pedestal body (2-1) at a lower position; The main column reinforcement is arranged inside the cap column (1), and the main column reinforcement includes a main column main reinforcement (11-1) and a main column stirrup (11-2); the main column main reinforcement (11-1) is arranged vertically for a circle and extends to the bottom surface of the cap body (2-1); the main column main reinforcement (11-1) and the main column stirrup (11-2) are tied or welded together; the main column stirrup (11-2) is evenly arranged along the main column main reinforcement (11-1), and a main column stirrup (11-2) is added at the cross-section change point of the cap column (1) and 100 mm above and below. The main column main reinforcement (11-1) is made of HRB400 grade steel bars, and the main column stirrups (11-2) are made of HPB300 grade steel bars; Cap steel bars are arranged inside the foundation cap (2), and the cap steel bars include upper main bars (12-1), lower main bars (12-2), cap stirrups (12-3), and cap tension bars (12-4). The upper main bars (12-1) and lower main bars (12-2) are arranged on the upper and lower surface bodies of the cap body (2-1) and the cap retaining wall (2-2). A plurality of cap stirrups (12-3) are arranged at intervals in a height direction, and the cap tension bars (12-4) are connected between the upper main bars (12-1) and the lower main bars (12-2). The upper main reinforcement (12-1) and the lower main reinforcement (12-2) are made of HRB400 grade steel bars, and the remaining foundation reinforcements are made of HPB300 grade steel bars; Anchor reinforcement bars (13) are arranged inside the foundation anchor bar (3), and the anchor reinforcement bars (13) include a main anchor bar (13-1), an end anchor bar (13-2) and a centering reinforcement bar (13-3). The main anchor bar (13-1) extends into the interior of the pedestal body (2-1), and one end located inside the pedestal body (2-1) is double-sidedly welded to the two end anchor bars (13-2). The centering reinforcement bar (13-3) is used to fix the main anchor bar (13-1) in the anchor hole, is trapezoidal in shape, and has two ends extending outwards to be welded to the main anchor bar (13-1). A plurality of anchor bars (13-3) are evenly arranged along the circumference of the same height of the main anchor bar (13-1) to form a group, and a group of centering reinforcement bars (13-3) is arranged every 2000 mm from 350 mm below the hole mouth. The main anchor bars (13-1) and the end anchor bars (13-2) are made of HRB400 grade steel bars, and the centering steel bars (13-3) are made of HPB300 grade steel bars; The pedestal body (2-1), the pedestal column (1) and the pedestal retaining wall (2-2) are integrally cast and formed.

2. The rock anchor foundation for reducing soil erosion of a power transmission line according to claim 1 is characterized by: A plurality of the drainage pipes (2-3) are arranged at equal intervals at the root of the cap retaining wall (2-2).

3. The rock anchor foundation for reducing soil erosion of a power transmission line according to claim 1, characterized in that: The foundation anchor rods (3) are evenly arranged on the lower surface of the platform body (2-1), and the distance between the foundation anchor rods (3) is 3 to 4 times the diameter of the foundation anchor rods (3); the length of the foundation anchor rods (3) is 3m to 8m.

4. The rock anchor foundation for reducing soil erosion of a power transmission line according to claim 1, characterized in that: The foundation anchor rod (3) is made of C30 fine stone concrete, the fine stone particle size is 5mm-8mm, the C30 fine stone concrete is mixed with an expansion agent, the 14d limited expansion rate in concrete water is greater than 0.02%, and the addition amount is 6%-8% of the cement amount.

5. The rock anchor foundation for reducing soil erosion of a power transmission line according to claim 1, characterized in that: The top surface of the cap column (1) is provided with anchor bolts (4) and concrete protective caps (5); The material of the anchor bolt (4) is Q235 steel, No. 35 steel or 42CrMo steel; The concrete protective cap (5) is made of C15 plain concrete.

6. A method for constructing a rock anchor foundation for a power transmission line to reduce soil erosion as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: (2) Excavation of foundation pit to form foundation pit; Drilling and cleaning of foundation anchor bolts (3); Anchor reinforcement (13) is inserted; Concrete pouring, compacting and curing of foundation anchors (3); Process the main column steel bars and the cap steel bars, and fix the anchor bolts (4) on the main column steel bars; Place the cap steel bars into the cap foundation pit; Casting cap columns (1) and foundation caps (2) on the main column steel bars and cap steel bars with concrete; After the pole tower and the wire rack are installed, the foundation bolts (4) are tightened again, and finally a concrete protective cap (5) is poured on the foundation bolts (4).

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