CN219219095U - Composite spiral anchor foundation for improving anti-overturning capacity of power transmission steel pipe pole - Google Patents

Abstract

The utility model discloses a composite spiral anchor foundation for improving the anti-overturning ability of steel pipe rods for power transmission, which comprises a main spiral anchor, the upper end of the main spiral anchor is arranged with a plurality of satellite spiral anchors at intervals along the circumferential direction, the main spiral anchor and the A connecting steel beam is arranged between the satellite helical anchors, and the connecting steel beam and the satellite helical anchor support are hinged to each other, and the top of the main helical anchor is provided with a connecting flange connected to the upper steel pipe rod. The overturning moment and horizontal force of the power transmission steel pipe rod of the utility model are transmitted to the main screw anchor by the connecting flange, and are jointly borne by the main screw anchor and the satellite screw anchor. Due to the increased distance between the satellite helical anchors and the inclined arrangement, the anti-overturning bearing capacity, anti-horizontal bearing capacity and corresponding foundation stiffness of the main helical anchors provided by the uplifting, downpressing, and horizontal bearing capacity of the satellite helical anchors are greatly improved, thereby effectively solving the problem of steel pipes. When the rod is designed on a single spiral anchor foundation, the anti-overturning bearing capacity is insufficient and the lateral deformation is too large.

Description

A Composite Spiral Anchor Foundation for Improving the Anti-overturning Capability of Transmission Steel Pipe Rods

technical field

The utility model relates to the technical field of transmission line foundations, in particular to a composite spiral anchor foundation for improving the anti-overturning ability of transmission steel pipe rods.

Background technique

The transmission line is the carrier of electric energy transmission in the power system. In the construction of the transmission line, the steel pipe pole is an important frame structure. Compared with the traditional iron tower structure, it has the advantages of high stability, small footprint, and good aesthetics. It is suitable for It is erected on the same pole with different voltage levels for multiple circuits, and is widely used in 110 and 220kV urban overhead transmission lines. Although steel pipe poles have many advantages, due to the towering structure, there is a large overturning moment under the action of wind load and ground wire load, which often leads to overturning accidents of steel pipe poles.

At present, the steel pipe rod foundation types mainly include block foundation, concrete pile foundation, steel pipe pile foundation, spiral anchor foundation, etc. Among them, the spiral anchor foundation has been widely promoted and applied by the State Grid in recent years because of its advantages of convenient, fast construction and low cost. However, this type of foundation has the problems of insufficient foundation stiffness and large deformation under overturning loads in coastal soft soil areas. In order to ensure the safety of the upper structure of the transmission line, the horizontal displacement of the lower foundation under the load should be controlled within 10~15mm. This deformation control target is currently difficult to achieve in soft soil areas with conventional spiral anchor foundations.

In order to solve the problem of insufficient bearing capacity and deformation control of conventional spiral anchor foundations under overturning loads of steel pipe rods, this application proposes a composite spiral anchor foundation for power transmission to improve the overturning resistance of steel pipe rods.

Utility model content

Aiming at the deficiencies of the existing technology, the utility model provides a composite spiral anchor foundation for power transmission to improve the anti-overturning ability of the steel pipe pole, which solves the problem of excessive overturning moment of the steel pipe pole under the action of wind load and ground wire load, and the anti-deformation capacity of the lower foundation. Insufficient problem.

In order to achieve the above purpose, the utility model provides the following technical solutions: a composite spiral anchor foundation for improving the anti-overturning ability of steel pipe poles for power transmission, including a main spiral anchor, and the upper end of the main spiral anchor is provided with several satellite spiral anchors at intervals along the circumferential direction. An anchor, a connecting steel beam is arranged between the main helical anchor and the satellite helical anchor, the connecting steel beam and the support of the satellite helical anchor are hinged to each other, and the top of the main helical anchor is provided with a steel pipe rod connected to the upper part. connecting flange.

The overturning moment and horizontal force of the transmission steel pipe pole are transmitted to the main screw anchor by the connecting flange, and are jointly borne by the main screw anchor and the satellite screw anchor. The overturning moment is shared by the main helical anchor and the satellite helical anchor. The overturning moment borne by the satellite helical anchor is converted into the uplift and downforce of the satellite helical anchor. The anchor and the satellite helical anchor are jointly responsible, and the satellite helical anchor provides the horizontal force by the component force of the uplift and downforce bearing capacity. The cross-sectional size of the connecting steel beams should be able to meet its own bending resistance requirements under the overturning moment.

Further, both the main spiral anchor and the satellite spiral anchor include three parts: an anchor head, an anchor rod and an anchor blade. The diameter is 200mm~500mm, and the anchor blade diameter is 400mm~1000mm.

Further, several wing plates are arranged along the circumferential direction of the main screw anchor, and the wing plates are rigidly connected to the connecting steel beam by bolts.

Further, the flange of the main screw anchor is perforated and the cross-sectional size is slightly smaller than the cross-sectional size of the connecting steel beam, and one side of the connecting steel beam is perforated, and the aperture and hole position match the aperture and hole position on the flange.

Further, the connecting steel beam is connected to the satellite screw anchor through a hinged joint.

Further, 4 to 6 satellite helical anchors are arranged around the main helical anchor, and the satellite helical anchors are evenly arranged around the main helical anchor.

Further, the satellite helical anchor is arranged obliquely at a certain angle with the vertical direction, and the inclination angle is 15°~30°, which is used to share a part of the horizontal force.

Further, the anchor rod top of the main screw anchor is reinforced with a cross beam within twice the diameter of the anchor rod, and the cross-sectional size of the cross beam is set to 50mm×50mm to prevent warping and damage at the top of the anchor rod due to concentrated force.

In summary, the utility model arranges several satellite spiral anchors radially around the main spiral anchor. The composite spiral anchor foundation is connected to the upper steel pipe rod through the connecting flange on the main spiral anchor. Connected by connecting steel beams, hinged between connecting steel beams and satellite helical anchors. The overturning moment and horizontal force of the transmission steel pipe pole are transmitted to the main screw anchor by the connecting flange, and are jointly borne by the main screw anchor and the satellite screw anchor. Due to the increased distance between the satellite helical anchors and the inclined arrangement, the anti-overturning bearing capacity, anti-horizontal bearing capacity and corresponding foundation stiffness of the main helical anchor provided by the uplifting, downpressing, and horizontal bearing capacity of the satellite helical anchors are greatly improved, thereby effectively solving the problem of steel pipes. When the rod is designed on a single spiral anchor foundation, the anti-overturning bearing capacity is insufficient and the lateral deformation is too large.

Description of drawings

Fig. 1 is the three-dimensional figure of the main screw anchor of the utility model band wing plate;

Fig. 2 is the top view of the main screw anchor with wing plate of the utility model;

Fig. 3 is a three-dimensional diagram of the utility model satellite helical anchor;

Fig. 4 is a three-dimensional diagram of the utility model connected steel beam;

Fig. 5 is a three-dimensional diagram of the composite helical anchor foundation of the present invention.

Labeling instructions: 1. Connecting flange; 2. Main screw anchor; 3. Satellite screw anchor; 4. Connecting steel beam; 5. Wing plate; 6. Articulated joint; 7. Bolt; 8. Cross beam.

Detailed ways

Referring to Fig. 1 to Fig. 5, a specific embodiment of a composite spiral anchor foundation for improving the anti-overturning ability of a power transmission steel pipe pole of the present invention will be further described.

Referring to the three-dimensional diagram of the composite spiral anchor foundation in Figure 5, it can be seen from the figure that the composite spiral anchor foundation of this embodiment includes a connecting flange 1, a main spiral anchor 2, a satellite spiral anchor 3, and a connecting steel beam 4. The satellite spiral anchors 3 are radially and uniformly distributed with the main spiral anchor 1 as the center. One end of the connecting steel beam 2 is connected to the wing plate 5 of the main spiral anchor 1 through a bolt 7, and the other end is hinged to the satellite spiral anchor 3 through a hinged joint 6. The satellite helical anchor 3 is inclined at a certain angle to the vertical direction, and the top 1 of the bolt of the main helical anchor 1 is provided with a cross beam 8 for reinforcement (as shown in FIG. 2 ).

The parameters of a southeast coastal soft soil layer are shown in the table below. The annual average groundwater level is -0.5m, and the highest groundwater level can reach 0m. The tower type of a transmission line is SGJ1, the height is 21m, the outer diameter of the tower is 1.61m, and the outer diameter of the lower flange is 2.12m. The foundation bears a downward load of 267kN, a horizontal load of 211kN, and a bending moment of 5207kN·m. Because the bending moment borne by the foundation, that is, the overturning moment, is too large, it is difficult for a single foundation form to meet the bearing capacity requirements, so a composite spiral anchor foundation is set up.

One main helical anchor 2 and four satellite helical anchors 3 (as shown in Figures 1 and 3) are arranged under each pole tower to form a composite helical anchor foundation. Among them, the satellite spiral anchor 3 has an inclination angle of 30°, and the connecting steel beam 4 is set in the form of a box girder (as shown in Figure 4). Both are 10mm, and both the screw anchor and the box girder are made of Q355 steel. The connecting flange 1 matches the lower flange of the pole tower. The outer diameter of the connecting flange 1 is 2.12m, the diameter of the bolt hole is 64mm, and the number of bolt holes is 24.

Table 1 Physical and mechanical parameters of formation

Note: m in the table is the proportional coefficient of the horizontal resistance coefficient of foundation soil.

The main screw anchor 2 is provided with three anchor plates, the burial depth is -4m, -8m, -10m respectively, the diameter of the anchor rod is 500mm, the diameter of the anchor plate is 1000mm, and the length, width and height of the steel cross beam 8 are 50mm, 50mm, 1000mm respectively , the wall thickness of the anchor rod and the thickness of the anchor plate are both 12 mm, and the pitch of the anchor plate is 100 mm. According to the bearing capacity calculation formula provided by "Code for Design of Spiral Anchor Foundation of Overhead Transmission Line Q/GDW 10584-2022" and "Technical Regulations for Design of Overhead Transmission Line Foundation DL/T5219-2014", the main spiral anchor is calculated to be 2 times The compressive bearing capacity is 1005.5kN, the horizontal bearing capacity is 114.96kN, and the anti-overturning bearing capacity is 4301kN·m. The calculation results show that the down-pressure bearing capacity meets the requirements, but the horizontal and anti-overturning bearing capacity does not meet the requirements, so this part of the load needs to be borne by the satellite screw anchor 3.

The satellite spiral anchor 3 is equipped with 3 anchor discs, and the buried depth is -1.25m, -2m, -2.75m after being inclined 30° in the vertical direction. The discs are located at -2.5m, -4.0m, and -5.5m on the top of the anchor rod respectively. The wall thickness of the anchor rod and the thickness of the anchor disc are both 12mm, and the pitch of the anchor disc is 100mm. According to the calculation formula in the specification, each satellite helical anchor 3 can provide an uplift bearing capacity of 461.9kN and a downward bearing capacity of 629.2kN along the inclined direction. The vertical and horizontal component forces of the uplift bearing capacity are 230.9kN and 230.9kN respectively, and the vertical and horizontal component forces of the downward pressure bearing capacity are 544.9kN and 314.6kN respectively. Therefore, the horizontal bearing capacity that a pair of satellite helical anchors 3 can provide is the sum of the horizontal direction components of the uplift bearing capacity and the downpress bearing capacity, that is, 545.5kN, and the anti-overturning force that can be provided is the vertical direction of the uplift bearing capacity and the downpress bearing capacity. The sum of the product of the direction and the length of the box girder is 1417kN·m.

When subjected to the overturning force, the box girder on one side can also provide part of the overturning resistance. This part of the resistance can be calculated according to the relevant formulas in the "Code for Design of Building Foundations GB50007-2011". Here, this resistance is used as a safety preparation.

Under the most unfavorable load angle, that is, the direction of horizontal force and bending moment is the same as that of a certain pair of satellite helical anchors 3, it cannot be decomposed into two component forces that are respectively borne by two pairs of satellite helical anchors 3. At this time, only a pair of satellite helical anchors 3 can provide horizontal and overturning resistance. The composite helical anchor can provide a horizontal bearing capacity of 661.1kN and an overturning bearing capacity of 5718.1kN m, which are respectively greater than the horizontal load 211kN and overturning moment that the foundation needs to bear. 5207kN·m, so it meets the force requirements.

The above descriptions are only preferred implementations of the present utility model, and the protection scope of the present utility model is not limited to the above-mentioned embodiments, and all technical solutions under the idea of the present utility model all belong to the protection scope of the present utility model. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principle of the utility model should also be regarded as the protection scope of the utility model.

Claims (8)

1. A composite spiral anchor foundation for promoting the anti-overturning ability of the transmission steel pipe rod is characterized in that: it comprises a main spiral anchor, and the upper end of the main spiral anchor is provided with some satellite spiral anchors at circumferential intervals, the main spiral anchor and A connecting steel beam is arranged between the satellite helical anchors, and the connecting steel beam and the satellite helical anchor support are hinged to each other, and the top of the main helical anchor is provided with a connecting flange connected to the upper steel pipe rod. 2. The composite spiral anchor foundation for improving the anti-overturning ability of transmission steel pipe rods according to claim 1, characterized in that: the main spiral anchor and the satellite spiral anchor all include three parts: an anchor head, an anchor rod, and an anchor blade. The diameter of the bolt of the anchor is 500mm~1000mm, the diameter of the anchor blade is 1000mm~1500mm; the diameter of the bolt of the satellite spiral anchor is 200mm~500mm, and the diameter of the anchor blade is 400mm~1000mm. 3. The composite spiral anchor foundation for improving the anti-overturning ability of transmission steel pipe rods according to claim 1, characterized in that: several wing plates are arranged along the circumferential direction of the main spiral anchor, and the wing plates and the connecting steel The beams are rigidly connected by bolts. 4. The composite spiral anchor foundation for improving the anti-overturning ability of the transmission steel pipe rod according to claim 3, characterized in that: the wing plate of the main spiral anchor is perforated and the cross-sectional size is slightly smaller than the cross-sectional size of the connecting steel beam. Holes are drilled on one side of the steel beam, and the hole diameter and hole position match the hole diameter and hole position on the flange. 5. The composite spiral anchor foundation for improving the overturning resistance of power transmission steel pipe poles according to claim 1, characterized in that: the connecting steel beam is connected to the satellite spiral anchor through a hinged joint. 6. The composite spiral anchor foundation for improving the anti-overturning ability of transmission steel pipe rods according to claim 1, characterized in that: 4 to 6 satellite spiral anchors are arranged around the main spiral anchor, and the satellite spiral anchors are evenly distributed along the periphery of the main spiral anchor. layout. 7. The composite spiral anchor foundation for improving the anti-overturning ability of power transmission steel pipe poles according to claim 6, characterized in that: the satellite spiral anchors are inclined at a certain angle to the vertical direction, and the inclination angle is 15°~30°. 8. The composite spiral anchor foundation for improving the anti-overturning ability of steel pipe rods for power transmission according to claim 1, characterized in that: the top of the anchor rod of the main spiral anchor is provided with a cross beam within the range of twice the diameter of the anchor rod for reinforcement, and the cross beam is reinforced. The beam section size is set to 50mm×50mm.

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