Fabricated truss-precast pile foundation for power transmission line

Abstract

The invention belongs to the technical field of electric power engineering. According to the assembly type truss-precast pile foundation for the power transmission line, adjacent precast piles are connected through horizontal tie bars, tower foot plates are located on the upper portions of the precast piles and connected with inclined rods, and the inclined rods are connected with the precast piles; the horizontal tie bars and the inclined bars form a truss structure, and the center of the top surface of the truss structure and the center of the bottom surface of the truss structure are eccentrically arranged; the lower portion is a hollow precast concrete square pile or a pipe pile, the upper portion is a hollow precast concrete member truss, the top of the truss is directly connected with a tower foot plate, concrete members are connected with the piles and the tower foot plate through pin shafts, field assembly is facilitated, adjustable bolts are arranged on connecting pieces, and installation precision is guaranteed. The defects of a common cast-in-place pile are overcome, the upper discrete hollow concrete truss replaces a bearing platform, and the problems of large self weight and on-site maintenance of the bearing platform are solved.

Description

Technical Field

[0001] The invention relates to the technical field of electric power engineering, and in particular to an assembled truss-prefabricated pile foundation for a power transmission line. Background Art

[0002] The statements in this section merely provide background art related to the present invention and do not necessarily constitute prior art.

[0003] Transmission lines usually use cast-in-place pile foundations in soft soil with shallow groundwater levels. Traditional cast-in-place pile foundations have disadvantages such as difficulty in ensuring construction quality, long on-site foundation maintenance time, and mud pollution.

[0004] With the rapid development of the power industry and the continuous construction of transmission lines, precast pile foundations have gradually been used. Their advantages lie in fast construction speed, easy quality control, and high bearing capacity. They are particularly suitable for engineering projects with tight schedules and high quality requirements. At the same time, with the continuous advancement of construction technology and materials, the performance and construction quality of precast concrete pile foundations have been further improved.

[0005] However, the inventors found that during the on-site construction of the precast pile foundation, the cast-in-place foundation requires maintenance, while the precast foundation has a larger deadweight and places higher requirements on road traffic conditions. Summary of the invention

[0006] In order to solve the shortcomings of the prior art, the present invention provides an assembled truss-precast pile foundation for power transmission lines, wherein the lower part is a hollow precast concrete square pile or pipe pile (i.e., a precast pile), and the upper part is a hollow precast concrete component truss, the top of the truss is directly connected to the tower foot plate, and the concrete component is connected to the precast pile and the tower foot plate by a pin shaft, which is convenient for on-site assembly, and the connecting parts are provided with adjustable bolts to ensure installation accuracy. The lower part adopts precast piles to solve the shortcomings of ordinary cast-in-place piles, and the upper discrete hollow concrete trusses replace the pedestal to solve the problems of heavy self-weight of the pedestal and on-site maintenance.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] An assembled truss-prefabricated pile foundation for a power transmission line comprises: a plurality of prefabricated piles at the bottom, adjacent prefabricated piles are connected by horizontal tie rods, a tower foot plate is located on the upper part of the prefabricated piles, and the tower foot plate is connected to an oblique rod, and the oblique rod is connected to the prefabricated piles;

[0009] The horizontal tie rods and the oblique rods form a truss structure, and the center of the top surface of the truss structure and the center of the bottom surface of the truss structure are eccentrically arranged.

[0010] As a further limitation of the present invention, a long hole and a pin hole are provided on the bottom pin connection piece, and the bottom pin connection piece is directly connected to the precast pile through a bolt passing through the long hole, and is connected to the horizontal tie rod through the pin hole.

[0011] As a further limitation of the present invention, one end of the horizontally adjustable connecting member is connected to the pin hole of the bottom pin connecting member through a pin bolt, and the other end of the horizontally adjustable connecting member is connected to the horizontal tie rod through an adjustable length bolt.

[0012] As a further limitation of the present invention, one side of the horizontal tie rod is connected to the horizontal adjustable connector via a connecting plate and an adjustable length bolt, and the other side of the horizontal tie rod is connected to the bottom pin connector corresponding to another precast pile via a bolt.

[0013] As a further limitation of the present invention, the upper portion of the oblique rod is connected to the upper adjustable connecting member via a connecting plate and an adjustable length bolt, and the bottom portion of the oblique rod is connected to the bottom pin connecting member via a bolt.

[0014] As a further limitation of the present invention, one end of the upper adjustable connecting member is connected to the tower foot plate through a pin bolt, and the other end of the upper adjustable connecting member is connected to the oblique rod through an adjustable length bolt.

[0015] As a further limitation of the present invention, the tower foot plate is connected to the upper adjustable connecting member through a pin shaft.

[0016] As a further limitation of the present invention, the horizontal tie rods and the diagonal rods are both hollow reinforced concrete members.

[0017] As a further limitation of the present invention, the diameter of the prefabricated piles at the bottom is D, the distance between the piles is 4D, the vertical height from the top surface of the truss to the top surface of the piles is H1, and the eccentricity between the center of the top surface and the center of the bottom surface of the truss is E;

[0018] E / H1 = foundation pullout force T / horizontal resultant force Txy corresponding to foundation pullout condition, or, E / H1 = foundation downforce N / horizontal resultant force Nxy corresponding to foundation downforce condition;

[0019] The length of the horizontal tie rod XL = 4D, the length of the long truss diagonal beam XHJ1 = ((2D + E) 2 +4D 2 +H1 2 ) 0.5 , the length of the short truss diagonal beam XHJ2 = ((2D-E) 2 +4D 2 +H1 2 ) 0.5 .

[0020] As a further limitation of the present invention, the precast pile embedding depth H2=1.8T, where T is the relative stiffness coefficient of the pile body.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention bears the load of the upper iron tower through the truss-pile structure system, which changes the traditional pedestal-pile force transmission system. The top and bottom centers of the truss are eccentrically set, which improves the force bearing performance of the foundation. The precast piles are used to solve the shortcomings of ordinary cast-in-place piles. The discrete hollow concrete trusses replace the pedestals, which solves the problems of heavy deadweight and on-site maintenance of the pedestals, and provides a solution for the use of precast assembled foundations in soft soil foundations of power transmission lines. The precast components are connected by pins to avoid on-site wet connection of the precast components, which greatly shortens the on-site construction period. Adjustable end plates are provided at the ends of the components to solve the positioning errors of the on-site pile foundation construction and ensure the installation accuracy.

[0023] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0025] Figure 1 This is a schematic diagram of the design system for the prefabricated truss-precast pile foundation structure;

[0026] Figure 2 is a schematic diagram of the bottom pipe pile and its connecting parts;

[0027] Figure 3 is a schematic diagram of a bottom pin connection;

[0028] Figure 4 It is a schematic diagram of a horizontally adjustable connecting piece and a length-adjusting bolt;

[0029] Figure 5 is a schematic diagram of a horizontal tie rod;

[0030] Figure 6 is a schematic diagram of the oblique rod;

[0031] Figure 7 It is a schematic diagram of the upper adjustable connecting piece and the length-adjusting bolt;

[0032] Figure 8 This is a schematic diagram of the tower base plate;

[0033] Among them, 1. precast piles; 2. diagonal rods; 3. horizontal tie rods; 4. tower base plates; 5. bottom pin connectors; 6. horizontally adjustable connectors; 7. upper adjustable connectors. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0035] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0036] In this implementation, a truss-prefabricated pile foundation for transmission lines that can be assembled on site is proposed, which has the advantages of reasonable foundation type force, light weight of a single component, and adjustable connectors according to on-site construction errors.

[0037] like Figure 1 As shown, the lower part of the present invention is a precast pile 1 foundation, and the upper part is a truss structure composed of precast concrete oblique components. The precast pile 1 foundations and the pile oblique components are connected by precast concrete horizontal rods. The top of the truss is directly connected to the tower foot plate 4. It is mainly composed of six parts, including the lower precast pile 1, the upper oblique rod 2, the horizontal tie rod 3, the lower pin node, the upper pin node and the adjustable end plate. The precast pile 1 adopts a hollow square pile or a pipe pile, and the upper oblique truss and the horizontal tie rod 3 adopt hollow precast concrete components. All connecting parts are pin-connected, which is convenient for on-site assembly. The connecting parts are provided with adjustable bolts to ensure installation accuracy.

[0038] The diameter of the precast pile 1 at the bottom is D, the pile spacing is 4D, the vertical height from the top surface of the truss to the top surface of the precast pile 1 is H1, and the eccentricity between the center of the top surface and the center of the bottom surface of the truss is E; where E / H1 = foundation pullout force T / horizontal resultant force Txy corresponding to the foundation pullout condition, or, E / H = foundation downforce N / horizontal resultant force N corresponding to the foundation downforce condition xy .

[0039] In this implementation, the length of the horizontal tie rod 3 is XL=4D, and the length of the long truss diagonal beam is XHJ1=((2D+E) 2 +4D 2 +H1 2 ) 0.5 ; Short truss diagonal beam length XHJ2 = ((2D-E) 2 +4D 2 +H1 2 ) 0.5 .

[0040] In this implementation, the cross-sections of the lower precast pile 1, the oblique truss (composed of the oblique rod 2) and the horizontal member (composed of the horizontal tie rod 3) are first selected, and the stress analysis of the structural system composed of the truss structure-precast pile is carried out. Then, the bearing capacity of the member is verified according to the stress conditions of the precast pile and each member, wherein the imaginary embedding depth of the precast pile 1 is H2=1.8T, and T is the relative stiffness coefficient of the pile body (m).

[0041] When the top of the precast pile 1 is subjected to upward pull and downward compression loads, due to the offset E between the center of the top surface of the truss and the center of the bottom surface of the foundation of the precast pile 1, the vertical force bending moment effect and the horizontal force bending moment effect acting on the center of the bottom surface of the foundation of the precast pile 1 offset each other, and the lower precast pile mainly bears the initial vertical force and horizontal force, thereby improving the bearing capacity of the foundation.

[0042] In this implementation, preferably, after the lower prefabricated pile 1 is driven into the lower foundation by a pile driver, the ends are connected to the bottom pin connector 5 by bolts to transfer vertical and horizontal loads; a reserved bolt hole is provided on the bottom pin connector 5, and the bottom pin connector 5 can be rotated to facilitate the horizontal tie rod 3 and the upper diagonal rod 2 to be put into place. After they are in place, the bolts are tightened to fix the bottom pin connector 5.

[0043] In this implementation, preferably, the precast pile 1 and the horizontal tie rod 3 are pin-connected through the pin hole reserved on the bottom pin connector 5, and the horizontal tie rod 3 is accurately installed through the adjustable end plate; the upper oblique rod 2 and the precast pile 1 are pin-connected through the bottom pin connector 5; the upper oblique rod 2 and the tower foot plate 4 are pin-connected through the bottom pin connector 5, and the flatness of the tower foot plate 4 and the foundation root opening are adjusted through the adjustable end plate.

[0044] More specifically, Figure 2 As shown, the prefabricated pile 1 at the bottom and its connecting piece, the prefabricated pile 1 is connected to the bottom pin connecting piece 5 through the connecting piece by bolts. Figure 3 is a schematic diagram of the bottom pin connector 5. The bottom pin connector 5 is provided with a long hole to facilitate the proper adjustment of the pin direction according to the actual construction position of the pile, and to facilitate the connection with the upper oblique rod 2. The bottom pin connector 5 is directly connected to the prefabricated pile 1 through bolts passing through the long hole, and is connected to the horizontal tie rod 3 through the pin hole at the end. d1 is the diameter of the pin 1, d2 is the diameter of the pin 2, and d3 is determined by the lower connecting bolt. d1, d2 and d3 are determined by calculation.

[0045] Figure 4It is a schematic diagram of the horizontally adjustable connecting member 6 and the length-adjusting bolt. One end of the horizontally adjustable connecting member 6 is connected to the bottom pin connecting member 5 through a pin bolt, and the other end of the horizontally adjustable connecting member 6 is connected to the horizontal tie rod 3 through an adjustable length bolt. A set of length-adjusting bolts includes a full-thread screw and 8 nuts, with two nuts on each side of each side plate. After tightening, tension and pressure are transmitted through the adjustable screw. d4 is the diameter of the length-adjusting screw, which is determined by calculation.

[0046] Figure 5 It is a schematic diagram of the horizontal tie rod 3. The horizontal tie rod 3 is a hollow reinforced concrete member. One side of the horizontal tie rod 3 is connected to the horizontal adjustable connector 6 through a connecting plate and an adjustable length bolt, and the other side of the horizontal tie rod 3 is connected to the bottom pin connector 5 through bolts. d5 is the inner hollow diameter, which is determined by calculation.

[0047] Figure 6 It is a schematic diagram of the diagonal rod 2. The diagonal rod 2 is a hollow reinforced concrete member. The upper part is connected to the upper adjustable connecting piece 7 through a connecting plate and an adjustable length bolt, and the bottom is connected to the bottom pin connecting piece 5 through bolts. d6 is the inner hollow diameter, which is determined by calculation.

[0048] Figure 7 It is an upper adjustable connecting piece 7 and a length-adjusting bolt. One end of the upper adjustable connecting piece 7 is connected to the tower foot plate 4 through a pin bolt, and the other end of the upper adjustable connecting piece 7 is connected to the diagonal rod 2 through an adjustable length bolt. A set of length-adjusting bolts includes a full-thread screw and 8 nuts, with two nuts on each side of each side plate. After tightening, tension and pressure are transmitted through the adjustable screw. d7 is the diameter of the length-adjusting screw, which is determined by calculation.

[0049] Figure 8 It is a schematic diagram of a tower foot plate 4, wherein the tower foot plate 4 is connected to an upper adjustable connecting member 7 via a pin, and the upper adjustable connecting member 7 is connected to the diagonal rod 2 via a length-adjusting bolt.

[0050] The above-mentioned embodiment only expresses one implementation mode of the present invention, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, such as adjusting the bottom piles to 5, 6 or more according to the foundation force, and adjusting the upper truss to follow the number of piles, which all belong to the protection scope of the present invention.

Claims

1. An assembled truss-prefabricated pile foundation for a power transmission line, characterized in that: include: A plurality of precast piles at the bottom, adjacent precast piles are connected by horizontal tie rods, a tower foot plate is located on the upper part of the precast piles, and the tower foot plate is connected to the oblique rods, and the oblique rods are connected to the precast piles; The horizontal tie rods and the oblique rods form a truss structure, and the center of the top surface of the truss structure and the center of the bottom surface of the truss structure are eccentrically arranged.

2. The assembled truss-prefabricated pile foundation for power transmission lines according to claim 1, characterized in that: The bottom pin shaft connecting piece is provided with a long hole and a pin shaft hole, and is directly connected to the prefabricated pile through a bolt passing through the long hole, and is connected to the horizontal tie rod through the pin shaft hole.

3. The assembled truss-prefabricated pile foundation for power transmission lines according to claim 2, characterized in that: One end of the horizontally adjustable connecting piece is connected to the pin hole of the bottom pin connecting piece through a pin bolt, and the other end of the horizontally adjustable connecting piece is connected to the horizontal tie rod through an adjustable length bolt.

4. The assembled truss-prefabricated pile foundation for power transmission lines according to claim 3, characterized in that: One side of the horizontal tie rod is connected to the horizontal adjustable connector through a connecting plate and an adjustable length bolt, and the other side of the horizontal tie rod is connected to the bottom pin connector corresponding to another precast pile through a bolt.

5. The assembled truss-prefabricated pile foundation for power transmission lines according to claim 2, characterized in that: The upper part of the oblique rod is connected with the upper adjustable connecting piece through a connecting plate and an adjustable length bolt, and the bottom of the oblique rod is connected with the bottom pin connecting piece through a bolt.

6. The assembled truss-prefabricated pile foundation for power transmission lines according to claim 6, characterized in that: One end of the upper adjustable connecting piece is connected to the tower foot plate through a pin bolt, and the other end of the upper adjustable connecting piece is connected to the oblique rod through an adjustable long bolt.

7. The assembled truss-prefabricated pile foundation for power transmission lines according to claim 6, characterized in that: The tower foot plate is connected to the upper adjustable connecting piece through a pin shaft.

8. The assembled truss-prefabricated pile foundation for power transmission lines according to any one of claims 1 to 7, characterized in that: The horizontal tie rods and diagonal rods are both hollow reinforced concrete components.

9. The assembled truss-prefabricated pile foundation for power transmission lines according to any one of claims 1 to 7, characterized in that: The diameter of the precast piles at the bottom is D, the pile spacing is 4D, the vertical height from the top surface of the truss to the top surface of the pile is H1, and the eccentricity between the center of the top surface and the center of the bottom surface of the truss is E; E / H1 = foundation pullout force T / horizontal resultant force Txy corresponding to foundation pullout condition, or, E / H1 = foundation downforce N / horizontal resultant force Nxy corresponding to foundation downforce condition; The length of the horizontal tie rod XL = 4D, the length of the long truss diagonal beam XHJ1 = ((2D + E) 2 +4D 2 +H1 2 ) 0.5 , the length of the short truss diagonal beam XHJ2 = ((2D-E) 2 +4D 2 +H1 2 ) 0.5 .

10. The assembled truss-prefabricated pile foundation for power transmission lines according to claim 9, characterized in that: The embedding depth of precast piles is H2=1.8T, where T is the relative stiffness coefficient of the pile body.

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