Prestressed anchor for synchronous coordinated tensioning and installation method

Abstract

The present invention belongs to the technical field of slope protection, and particularly relates to a prestressed anchor and installation method for synchronous coordinated tensioning. The prestressed anchor is in the shape of a cone, and is provided with a plurality of curved holes that penetrate from the bottom of the cone to the cone surface of the cone side, and the plurality of curved holes are arranged circumferentially with the central axis of the prestressed anchor as the axis. The present invention cleverly sets the upper surface into a conical polyhedron shape on the basis of the traditional anchor, so that each bundle of anchor cables can be tensioned in various directions separately, further increasing the working area of ​​the jack, and can well meet the requirements of synchronous coordinated tensioning of multiple jacks. The present invention sets an arc-shaped anchor cable outlet hole to provide bending and surrounding support for the anchor cable, avoiding the problem of corner folding at the anchor cable anchoring hole, effectively converting the oblique force on the anchor cable during tensioning of the prestressed anchor cable into an axial force along the anchor cable, and ensuring the tensioning effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of slope protection, and in particular relates to a prestressed anchor for synchronous coordinated tensioning and an installation method thereof. Background Art

[0002] An anchor is a permanent anchoring device used in prestressed concrete. It is an anchoring tool installed in post-tensioned structures or components to maintain the tension of the prestressed tendons and transfer it to the concrete. Prestressing is the process of applying tension to a component in advance, causing the prestressed component to undergo compressive stress, which in turn causes it to deform to a certain extent to cope with the loads on the structure itself. Before the engineering component is subjected to external loads, prestressing is applied to the steel strands in the tension module to improve the component's bending resistance and stiffness, delay the appearance of cracks, and increase the component's durability.

[0003] For the currently widely used pressure-dispersed anchor cables, the traditional tensioning methods will cause technical defects such as load loss and unevenness in each unit anchor cable. The multi-jack parallel synchronous coordinated tensioning method can effectively avoid the above problems. However, the traditional anchor tensioning working surface is a plane, which cannot achieve multi-jack synchronous coordinated tensioning. Summary of the Invention

[0004] The purpose of the present invention is to provide a prestressed anchor and installation method for synchronous coordinated tensioning in order to solve the problem that the existing anchor does not have the synchronous coordinated tensioning technology during the synchronous coordinated tensioning process of multiple jacks in parallel in the prior art.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A prestressed anchor for synchronous coordinated tensioning, the prestressed anchor is in the shape of a cone, and is provided with a plurality of curved holes extending from the bottom of the cone to the side conical surface of the cone, and the plurality of curved holes are arranged circumferentially with the central axis of the prestressed anchor as the axis.

[0007] In the technical solution of the present invention, in order to adapt to the construction requirements of coordinated and synchronous tensioning of multiple jacks, the shape of the prestressed anchor is structurally optimized and designed into a cone shape. In addition, the hole for passing the anchor cable is adaptively changed into a curved hole. A curved hole means that the central axis of the hole is not a curve, but a curved line. The inlet end of the curved hole is the bottom of the cone, and the outlet end is the cone surface of the cone. Because the area of ​​the cone surface is several times larger than that of the conventional anchor, and based on the advantage of the shape, the working surface space of multiple curved holes can be dispersed on the cone surface, which overcomes the problem that the anchor holes of the existing conventional anchor are concentrated on the same working surface, which makes it impossible for the jacks to complete the synchronous and coordinated tensioning well, resulting in low construction efficiency and load imbalance. Technical defects.

[0008] As a preferred embodiment of the present invention, the prestressed anchor is a conical polyhedron with 4 to 8 conical surfaces, each of which is a trapezoidal structure when viewed from the side, and the areas of the conical surfaces are equal.

[0009] As a preferred embodiment of the present invention, the angle α between each of the tapered surfaces and the side surface of the prestressed anchor is in the range of 115° to 145°. Angle α that is too small or too large is not conducive to the construction operation of the jack. After multiple tests, it was found that when α is in the range of 115° to 145°, the operating space of the jack is most suitable.

[0010] As a preferred solution of the present invention, the thickness of the prestressed anchor is H, and the range of H is 5 cm to 10 cm.

[0011] As a preferred embodiment of the present invention, the curved hole includes an anchor cable entrance section, a curved section and an anchor cable extension section, and the inner diameter of the curved hole has the following changing trend: from the anchor cable entrance section to the anchor cable extension section, the hole diameter changes from large to small and then to large.

[0012] The diameter of the curved section of the curved hole is smaller than the two ends of the curved hole. The purpose of the first stage of the hole diameter decreasing from large to small is to facilitate the penetration of the anchor cable, reduce the contact area between the anchor cable and the anchor during tensioning, and reduce friction. The purpose of the second stage of the hole diameter decreasing from small to large is to facilitate the placement of the tapered clamp so that when locked, the anchor clamp contracts into the hole to clamp the anchor cable.

[0013] As a preferred embodiment of the present invention, a first transition section is provided from the curved section to the anchor cable extension section, and a second transition section is provided from the anchor cable entrance section to the curved section. The provision of the first and second transition sections ensures the smoothness of the inner wall of the hole, ensuring that the anchor cable can pass through smoothly.

[0014] As a preferred solution of the present invention, the extending section of the anchor cable is provided with a clamp that cooperates with the curved hole.

[0015] Preferably, the anchor cable extension section is a trapezoidal hole. The trapezoidal hole refers to a structure in which the cross section of the anchor cable extension section is a trapezoid, which is used to securely install the clamp after the anchor cable is tensioned.

[0016] As a preferred embodiment of the present invention, the spacing between adjacent curved holes is determined by the number of tapered surfaces. When the number of tapered surfaces is large, the spacing is small, and when the number of tapered surfaces is small, the spacing is large. Specifically, the spacing referred to herein is the shortest distance between the centers of two adjacent anchor holes on the bottom plane of the anchor. Preferably, the R value ranges from 3 to 6 cm.

[0017] A method for installing an anchor cable prestressed anchor, comprising the above-mentioned prestressed anchor with synchronous coordinated tensioning, comprises the following steps:

[0018] S1. Calculate the actual anchor tension F1 of a single anchor cable, and its expression is:

[0019]

[0020] Among them, F2 is the design anchor tension of the anchor cable, μ is the turning coefficient, and α is the internal angle of the anchor;

[0021] S2. Pass the anchor cables through the prestressed anchors in sequence according to their numbers and fix the positions of the anchors;

[0022] S3, installing clips on the plurality of conical surfaces; fixing the tensioning jacks of each bundle of anchor cables on each single bundle of anchor cables in sequence according to the principle of symmetry, with the jacks being installed at positions corresponding to the conical surfaces;

[0023] S4. Synchronously and coordinately tension each bundle of anchor cables according to the actual tensioning force of the jacks;

[0024] S5. After tensioning to the tensioning force F1, each bundle of anchor cables is locked to complete the installation and fixation of multiple bundles of anchor cables in the prestressed anchor.

[0025] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0026] 1. The present invention cleverly sets the upper surface of the traditional anchor into a conical polyhedron shape, so that each bundle of anchor cables can be tensioned individually in various directions, further increasing the working area of ​​the jack, and can well meet the requirements of synchronous and coordinated tensioning of multiple jacks.

[0027] 2. The present invention cleverly arranges arc-shaped anchor cable outlet holes to provide bending and surrounding support for the anchor cables, avoiding the problem of corner bending at the anchor cable anchoring hole mouth, and effectively converting the oblique force on the anchor cable during prestressed anchor cable tensioning into axial force along the anchor cable, while ensuring the tensioning effect.

[0028] 3. The prestressed anchor of the present invention is die-cast in one piece, which ensures reliable fixation and convenient installation. With this structure, multiple bundles of anchor cables can be tensioned simultaneously during installation and tensioning, and the tensioning force of each bundle of anchor cables is evenly distributed, making the structure more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the three-dimensional structure of the prestressed anchor of the present invention;

[0030] Figure 2 1 is a schematic structural diagram of the prestressed anchor of the present invention from a top view;

[0031] Figure 3 1 is a schematic structural diagram of a prestressed anchor of the present invention from a cross-sectional perspective;

[0032] Figure 4 1 is a schematic structural diagram of a prestressed anchor of the present invention from a side view;

[0033] Figure 5 It is a force distribution diagram of the bent hole of the prestressed anchor of the present invention;

[0034] Figure 6 1 is a schematic structural diagram of the prestressed anchor of the present invention from a bottom perspective;

[0035] Figure 7 It is a structural schematic diagram of the coordination between the anchor hole and the clamp of the prestressed anchor of the present invention;

[0036] Icon: 1-anchor; 2-curved hole; 3-conical surface; 4-first transition section, 5-second transition section, 21-anchor cable entrance section, 22-bend section, 23-anchor cable extension section, 6-anchor cable, 7-clamp. DETAILED DESCRIPTION

[0037] The present invention will be described in detail below with reference to the accompanying drawings.

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present 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 only used to explain the present invention and are not intended to limit the present invention.

[0039] Example 1

[0040] A prestressed anchor 1, such as Figure 1-7 As shown, the prestressed anchor 1 is a frustum-shaped structure. The prestressed anchor 1 is provided with a plurality of curved holes 2 extending from the bottom of the frustum to the side conical surface 3 of the frustum. The plurality of curved holes 2 are arranged circumferentially with the central axis of the prestressed anchor 1 as the axis. Specifically, the side conical surface 3 of the prestressed anchor 1 is a multi-faceted conical surface 3 structure. In this embodiment, the prestressed anchor 1 includes six conical surfaces 3, each of which is a trapezoidal structure when viewed from the side, and the areas of the conical surfaces 3 are equal. The vertical height of the prestressed anchor 1 is H, and the range of H is 5 cm to 10 cm. Specifically, the prestressed anchor 1 includes a frustum and a prism from top to bottom. More specifically, the angle between the conical surface 3 and the side of the anchor is α, and the range of α is: 115° to 145°. Angle α is not conducive to the construction operation of the jack if it is too small or too large. After many tests, it was found that when the range of α is 115°~145°, the operating space of the jack is most suitable.

[0041] like Figure 3As shown, the curved hole 2 includes three sections, namely the anchor cable entrance section 21, the curved section 22 and the anchor cable extension section 23. The curved section 22 is arc-shaped, and the inner diameter of the curved hole 2 has the following change trend: from the anchor cable entrance section 21 to the anchor cable extension section 23, the hole diameter changes from large to small and then becomes larger.

[0042] The diameter of the curved section 22 of the curved hole 2 is smaller than the two ends of the curved hole 2. The purpose of the first stage of the diameter changing from large to small is to facilitate the guidance of the anchor cable through the hole, reduce the contact area between the anchor cable 6 and the anchor during the tensioning process, and reduce friction; the purpose of the second stage of the diameter changing from small to large is to facilitate the placement of the tapered clamp 7 so that when locked, the anchor can be retracted into the hole to clamp the anchor cable 6.

[0043] A first transition section 4 is provided from the curved section 22 to the anchor cable extension section 23, and a second transition section 5 is provided from the anchor cable entrance section 21 to the curved section 22. The provision of the first transition section 4 and the second transition section 5 ensures the smoothness of the inner wall of the hole and ensures that the anchor cable 6 can pass through smoothly.

[0044] The anchor cable extension section is provided with a clamp 7 that cooperates with the curved hole 2. The anchor cable extension section 23 is a trapezoidal hole. The trapezoidal hole refers to the cross-section of the anchor cable extension section 23. This structure is used to securely install the clamp 7 after the anchor cable 6 is tensioned.

[0045] The spacing between adjacent curved holes 2 is determined by the number of tapered surfaces 3. When the number of tapered surfaces 3 is large, the spacing is small, and when the number of tapered surfaces 3 is small, the spacing is large. Specifically, the spacing here refers to the shortest distance between the centers of two adjacent anchor holes on the bottom plane of the anchor. Preferably, the R value ranges from 3 to 6 cm.

[0046] In the technical solution of this embodiment, in order to adapt to the construction requirements of coordinated and synchronous tensioning of multiple jacks, the shape of the prestressed anchor 1 is structurally optimized and designed into a cone shape. In addition, the hole for passing the anchor cable is adaptively changed into a curved hole. A curved hole means that the central axis of the hole is not a curve, but a curved line. The inlet end of the curved hole is the bottom of the cone, and the outlet end is the cone surface 3 of the cone. Because the area of ​​the cone surface 3 is several times larger than that of the conventional anchor, and based on the advantage of the shape, the working surface space of multiple curved holes can be dispersed on the cone surface 3, which overcomes the problem that the anchor holes of the existing conventional anchor are concentrated on the same working surface, which makes it impossible for the jacks to complete the synchronous and coordinated tensioning well, resulting in low construction efficiency and technical defects of load imbalance.

[0047] In the technical solution of this embodiment, an arc-shaped anchor cable outlet hole is cleverly set to provide bending and surrounding support for the anchor cable, avoiding the problem of corner bending at the anchor cable anchoring hole mouth, and effectively converting the oblique force on the anchor cable during prestressed anchor cable tensioning into axial force along the anchor cable, while ensuring the tensioning effect.

[0048] Example 2

[0049] A method for installing an anchor cable prestressed anchor 1, wherein the anchor is installed in conjunction with the anchor cable, and the prestressed anchor 1 is tensioned synchronously and coordinated as described in Example 1;

[0050] The specific steps are as follows:

[0051] S1. Calculate the actual anchor tension of a single anchor cable, which is expressed as:

[0052]

[0053] Wherein, is the design anchor tension of the anchor cable, is the turning coefficient, and is the internal angle of the anchor;

[0054] S2, pass the anchor cables through the prestressed anchor 1 in sequence according to their numbers, and fix the position of the anchor;

[0055] S3, installing clips on the plurality of conical surfaces 3; fixing the tensioning jacks of each bundle of anchor cables on each single bundle of anchor cables in sequence according to the principle of symmetry, with the jacks being installed at positions corresponding to the conical surfaces 3;

[0056] S4. Synchronously and coordinately tension each bundle of anchor cables according to the actual tensioning force of the jacks;

[0057] S5. After tensioning to the tensioning force F1, each bundle of anchor cables is locked to complete the installation and fixation of multiple bundles of anchor cables on the prestressed anchor 1.

[0058] Through this method, multiple jacks can use the corresponding conical surface 3 on the anchor as the working surface, and multiple anchor cables can be tensioned and fixed synchronously. For anchor cables with different free section lengths, even if there are different elongation deformations, the same tensioning effect can be achieved between the anchor cables.

[0059] 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 in the scope of protection of the present invention.

Claims

1. A prestressed anchor for synchronous coordinated tensioning, characterized in that: The prestressed anchor (1) is a frustum-shaped polyhedron structure, the conical surface (3) of the prestressed anchor (1) is a multi-faceted conical surface (3) structure, and the number of the conical surfaces (3) is 4-8; the angle between each conical surface (3) and the side surface of the prestressed anchor (1) is α, and the range of α is: 115°-145°; The prestressed anchor (1) is provided with a plurality of curved holes (2) extending from the bottom of the cone to the conical surface (3) on the side of the cone, and the plurality of curved holes (2) are arranged circumferentially with the central axis of the prestressed anchor (1) as the axis; The curved hole (2) comprises an anchor cable entrance section (21), a curved section (22) and an anchor cable extension section (23); the curved section (22) is arc-shaped; the inner diameter of the curved hole (2) has the following variation trend: from the anchor cable entrance section (21) to the anchor cable extension section (23), the hole diameter changes from large to small and then to large; The path design of the curved hole (2) is used to convert the tensioning oblique force into the axial force along the anchor cable.

2. The prestressed anchor for synchronous coordinated tensioning according to claim 1, characterized in that: The vertical height of the prestressed anchor (1) is H, and the range of H is: 5cm-10cm.

3. The prestressed anchor for synchronous coordinated tensioning according to claim 1, characterized in that: A first transition section (4) is provided from the curved section (22) to the anchor cable extension section (23), and a second transition section (5) is provided from the anchor cable inlet section (21) to the curved section (22).

4. The prestressed anchor for synchronous coordinated tensioning according to claim 1, characterized in that: The anchor cable extension section (23) is a trapezoidal hole.

5. The prestressed anchor for synchronous coordinated tensioning according to claim 4, characterized in that: The hole spacing between adjacent curved holes (2) is R, and the range of R is 3-6 cm.

6. The prestressed anchor for synchronous coordinated tensioning according to claim 1, characterized in that: The anchor cable extension section (23) is provided with a clamp (7) that matches the curved hole (2).

7. A method for installing an anchor cable prestressed anchor, characterized in that: A prestressed anchor with synchronous and coordinated tensioning according to any one of claims 1 to 6; The steps include: S1. Calculate the actual anchor tension F1 of a single anchor cable, and its expression is: Among them, F2 is the design anchor tension of the anchor cable, μ is the turning coefficient, and α is the internal angle of the anchor; S2. Pass the anchor cables through the prestressed anchors in sequence according to their numbers and fix the positions of the anchors; S3, installing clips on the plurality of conical surfaces; fixing the tensioning jacks of each bundle of anchor cables on each single bundle of anchor cables in sequence according to the principle of symmetry, with the jacks being installed at positions corresponding to the conical surfaces; S4. Synchronously and coordinately tension each bundle of anchor cables according to the actual tensioning force of the jacks; S5. After tensioning to the tensioning force F1, each bundle of anchor cables is locked to complete the installation and fixation of multiple bundles of anchor cables in the prestressed anchor.

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