Pile-anchor supporting structure for pre-stressed anchor cable tensioning of concrete pedestal

Abstract

The utility model discloses a pile-anchor supporting structure for pre-stressed anchor cable tensioning of a concrete pedestal, which comprises a fender post, a top beam is connected above the fender post, a main reinforcement of the fender post is welded with a pre-embedded anchor cable sleeve, and a lateral reinforcing mesh and a transverse tie bar are laterally erected on the fender post; a pre-stressed anchor cable is placed in the pre-embedded anchor cable sleeve and then is grouted, the pre-stressed anchor cable penetrates through the fender post, and the tail end of the pre-stressed anchor cable is fixedly connected with a guide cap; reinforcing meshes are embedded in the positions, close to the front ends of the pre-stressed anchor cables, of the fender posts, and concrete is poured to form a pedestal; and after the pre-stressed anchor cables are locked, anchor sealing reinforcing steel bars are embedded into the pedestal concrete, and anchor sealing concrete is poured into the pedestal concrete. The pre-embedded anchor cable sleeve is arranged in the fender post, so that the pre-stressed anchor cable penetrates through the fender post, the force of the pedestal is transmitted to the fender post, the stress of the pedestal is obviously reduced, and the integrity of the pre-stressed anchor cable, the pedestal and the fender post is improved.

Description

Technical Field

[0001] The utility model belongs to the field of deep foundation pit supporting structures, in particular to a pile anchor supporting structure for tensioning prestressed anchor cables on a concrete pedestal. Background Art

[0002] Pile-anchor support is a foundation pit support system developed on the basis of rock anchor theory research. It has clear force, convenient construction, and does not interfere with the excavation of the foundation pit. It effectively shortens the construction period and reduces costs. The pile-anchor support system has become a widely used support method in foundation pit support projects due to its safety and economic characteristics. The traditional pile-anchor support system usually drives the anchor cable into the pile, then sets up the steel bracket and steel waist beam, and then tensions the prestressed anchor cable through the pedestal on the steel waist beam. The foundation pit needs to be excavated in layers, which prolongs the construction period, increases the cost, and increases the possibility of water leakage. At the same time, the waist beam has a certain width, which increases the width of the foundation pit excavation, and the force on the pedestal is often large, which has the risk of damage.

[0003] The significance of solving the above technical problems lies in that, compared with the traditional pile-anchor support system, the pile-anchor support structure of the concrete pedestal for prestressed anchor cable tensioning of the utility model has the characteristics of stable pedestal structure, no need to set up waist beams and brackets, no need for long-distance layered excavation of foundation pits, reduced possibility of water leakage, reduced width of foundation pit excavation, saving construction period and cost, and has broad promotion prospects. Utility Model Content

[0004] The utility model aims to solve the shortcomings of the pedestal being subjected to large forces, requiring the installation of steel waist beams and steel supports, requiring layered excavation of foundation pits, increasing the width of foundation pit excavation, long construction period and high construction cost, and provides a pile-anchor support structure and a construction method for prestressed anchor cable tensioning on a concrete pedestal.

[0005] The technical solution adopted by the utility model to solve this problem is:

[0006] A pile-anchor support structure for prestressed anchor cable tensioning on a concrete pedestal, comprising a retaining pile, a crown beam is connected to the top of the retaining pile, a pre-embedded anchor cable sleeve is welded to the main reinforcement of the retaining pile, and a lateral steel mesh and transverse tensioning reinforcement are arranged on the side of the retaining pile;

[0007] A prestressed anchor cable is placed through an anchor hole in the pre-buried anchor cable casing and then grouting is performed. The prestressed anchor cable passes through the retaining pile, and the end of the prestressed anchor cable is fixedly connected to a guide cap;

[0008] The concrete pedestal steel mesh is implanted near the front end of the prestressed anchor cable and concrete is poured to form a pedestal;

[0009] It also includes a matching fixed anchor, which locks the prestressed anchor cable, implants anchor steel bars in the pedestal and pours anchor concrete.

[0010] Preferably, the prestressed anchor cable is divided into a free section and an anchoring section, and the free section is placed in a PVC sleeve.

[0011] Further preferably, the PVC sleeve has no joint.

[0012] Further preferably, a grouting pipe is installed in the pre-buried anchor cable casing, and the prestressed anchor cable is installed through a wire ring and a tightening ring inside the pre-buried anchor cable casing.

[0013] Further preferably, the wire ring and the tightening ring on the anchoring section are arranged at intervals.

[0014] Further preferably, the stringing rings and the tightening rings of the anchoring section are arranged at intervals of 1 m, and a stringing ring is arranged at intervals of 3 m in the free section.

[0015] Further preferably, the prestressed anchor cable is made of 7 steel wires twisted into a standard steel strand.

[0016] Further preferably, the concrete pedestal steel mesh is provided with 4 layers, with a layer spacing of 100m, and the depth of the steel mesh implanted into the retaining piles is not less than 250mm.

[0017] Further preferably, the length of the anchor steel bars embedded in the pedestal concrete is not less than 250 mm, and the anchor steel bars are single-layered with a spacing of 80 mm.

[0018] The beneficial effects of the utility model are:

[0019] 1. Pre-buried anchor cable casings are made in the retaining piles to allow the prestressed anchor cable to penetrate the retaining piles. The prestressed anchor cable is tensioned by setting a concrete pedestal on the pile body, and the force of the pedestal is transferred to the retaining piles, which significantly reduces the force on the pedestal and improves the integrity of the prestressed anchor cable, pedestal and retaining piles.

[0020] Compared with post-drilling and inserting prestressed anchor cables, the structural integrity and local integrity are better, and the retaining piles are effectively connected to the mesh shotcrete between the piles, reducing the possibility of water leakage between the piles and the piles.

[0021] 2. The concrete pedestal has a simple structure, simple construction process and easy to ensure construction quality, which shortens the construction period.

[0022] 3. The position of the prestressed anchor cable can be flexibly arranged according to the depth of the foundation pit and the distribution of soil layers, which is conducive to controlling the local and overall deformation of the structure and reducing the risk of slope collapse or local instability.

[0023] 4. No need to set up waist beams and supports, which reduces the width of foundation pit excavation, reduces the amount of earth excavation and backfilling, increases the safe distance between the foundation pit and surrounding buildings, saves project costs and construction period, and saves construction period to some extent, also improves the construction safety of the entire project.

[0024] 5. There is no need to excavate the foundation pit in layers. The excavation sequence can be determined according to the progress of the project, and anchors can be placed at the excavation location as they are dug, which increases the flexibility of the construction process.

[0025] Therefore, compared with the traditional pile-anchor support system, the utility model has the characteristics of strong structural integrity, simple process, high safety, easy to ensure construction quality, etc., while also saving construction period and cost, and has broad promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The technical solution of the utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it should be understood that these drawings are designed only for the purpose of explanation and are not intended to limit the scope of the utility model. In addition, unless otherwise specified, these drawings are only intended to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0027] Figure 1 It is an overall cross-sectional view of the pile-anchor support system provided by the utility model;

[0028] Figure 2 yes Figure 1 A local enlarged schematic diagram of the A in FIG.

[0029] Figure 3 It is a cross-sectional view of the concrete pedestal steel mesh provided by the utility model;

[0030] Figure 4 It is a concrete elevation view of the pedestal provided by the utility model;

[0031] Figure 5 It is a plan view of the anchor steel bar provided by the utility model.

[0032] In the figure:

[0033] 1. Guard piles; 2. Crown beam; 3. Pedestal; 4. Pre-buried anchor cable casing; 5. Lateral steel mesh; 6. Transverse tensioning bars; 7. Concrete pedestal steel mesh; 8. PVC casing; 9. Matching fixed anchors; 10. Wire ring; 11. Tightening ring; 12. Prestressed anchor cable; 1 cap; 15. Anchor-sealing concrete; 16. Anchor-sealing steel bars; 17. Cement mortar; 18. Anchor hole. DETAILED DESCRIPTION

[0034] First of all, it should be noted that the specific structure, features and advantages of the present invention will be specifically described below by way of example, but all descriptions are only for illustration and should not be understood as limiting the present invention in any way. In addition, any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature displayed or implied in the drawings, can still be combined or deleted between these technical features to obtain more other embodiments of the present invention that may not be directly mentioned in this document. In addition, in order to simplify the drawings, the same or similar technical features may be marked in only one place in the same drawing.

[0035] In the present utility model, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the utility model according to the specific circumstances.

[0036] The following is combined with Figure 1 -Attached Figure 5 The utility model is described in detail.

[0037] Embodiment 1:

[0038] A pile-anchor support structure for prestressed anchor cable tensioning on a concrete pedestal, comprising a retaining pile 1, a crown beam 2 is connected to the upper part of the retaining pile 1, a pre-embedded anchor cable sleeve 4 is welded to the main reinforcement of the retaining pile 1, and a lateral steel mesh 5 and a transverse tensioning reinforcement 6 are erected laterally on the retaining pile 1;

[0039] The prestressed anchor cable 12 is placed in the pre-buried anchor cable sleeve 4 through the anchor hole 18 and then grouting is performed. The prestressed anchor cable 12 passes through the retaining pile 1, and the end of the prestressed anchor cable 12 is fixedly connected to the guide cap 14;

[0040] The concrete pedestal steel mesh 7 is implanted near the front end of the prestressed anchor cable 12 in the retaining pile 1 and concrete is poured to form a pedestal 3;

[0041] It also includes a matching fixed anchor 9, which, after locking the prestressed anchor cable 12, implants anchor steel bars 16 into the pedestal 3 and pours anchor concrete 15.

[0042] Furthermore, in the embodiment, it can also be considered that the prestressed anchor cable 12 is divided into a free section and an anchoring section, and the free section is placed in the PVC sleeve 8.

[0043] Furthermore, in the embodiment, it can also be considered that the PVC sleeve 8 has no joint.

[0044] Furthermore, in the embodiment, it can also be considered that a grouting pipe 13 is installed in the pre-buried anchor cable casing 4, and the prestressed anchor cable 12 is installed through the wire ring 10 and the clamp ring 11 inside the pre-buried anchor cable casing 4.

[0045] The wire ring 10 is made of first-class steel with a diameter of 8 mm, and the tight hoop 11 is made of No. 16 lead wire wound twice.

[0046] Furthermore, in the embodiments, it can also be considered that the wire ring 10 and the clamp ring 11 on the anchoring section are arranged at intervals.

[0047] Furthermore, in the embodiment, it can be considered that the wire ring 10 and the clamp ring 11 of the anchoring section are arranged at intervals of 1m, and the free section is provided with a wire ring 10 every 3m. This interval setting and distance can ensure that the prestressed anchor cable 12 is straight.

[0048] Furthermore, in the embodiment, it can also be considered that the prestressed anchor cable 12 is made of 7 steel wires twisted into a standard steel strand.

[0049] The prestressed anchor cable 12 is made of 7 steel wires twisted into a standard steel strand with a nominal diameter of 15.20 mm and a tensile strength of 1860 MPa.

[0050] Furthermore, in the embodiment, it can also be considered that the concrete pedestal steel mesh 7 is set to 4 layers with a layer spacing of 100m, and the depth of the steel mesh 7 implanted into the retaining pile 1 is not less than 250mm.

[0051] In this embodiment, the concrete pedestal steel mesh 7 is grade 3 steel with a diameter of 16 mm, the implantation depth of the steel mesh 7 is preferably 250 mm, the steel mesh 7 has four layers, the layer spacing is 100 mm, and the pedestal concrete 3 uses C30 concrete.

[0052] Furthermore, in the embodiment, it can also be considered that the length of the anchor steel bar 16 embedded in the pedestal concrete 3 is not less than 250 mm, and the anchor steel bar 16 is a single layer with a spacing of 80 mm.

[0053] In this embodiment, the preferred length of the anchor steel bar 16 implanted in the pedestal concrete 3 is 250 mm, the anchor steel bar 16 is a first-class steel with a diameter of 12 mm, the anchor steel bar 16 is a single layer with a spacing of 80 mm, and the anchor concrete 15 is C30 non-shrinkage fine stone concrete.

[0054] Embodiment 2:

[0055] The above utility model structure is applied to the pile anchor support construction method using a concrete pedestal for prestressed anchor cable tensioning, and the specific steps are as follows:

[0056] Step S1: Construction of retaining pile 1;

[0057] After the site is cleaned, the steel cage of the retaining pile 1 is hoisted, the pre-buried anchor cable sleeve 4 is welded to the main reinforcement of the retaining pile 1, and then concrete is poured to form the retaining pile 1;

[0058] Step S2: pouring the top crown beam, excavating the foundation pit, and spraying concrete;

[0059] Tie the steel cage of the crown beam 2 on the top of the retaining pile 1 and pour concrete to form the crown beam 2;

[0060] Excavating a foundation pit, and installing prestressed anchor cables 12 during excavation to maintain the stability of the retaining piles 1;

[0061] After excavation, the working surface between the retaining piles 1 is trimmed, the lateral steel mesh 5 is tied to the retaining piles 1, the transverse tie bars 6 are implanted into the retaining piles 1, and the concrete between the piles is sprayed;

[0062] Step S3: Anti-corrosion treatment of anchor cables;

[0063] The prestressed anchor cable 12 is a standard steel strand made of multiple steel wires, which is divided into a free section and an anchoring section. Each steel strand is rust- and oil-free.

[0064] The free section of the prestressed anchor cable 12 is coated with lubricating oil or anti-corrosion paint on its surface, wrapped with plastic sheeting, and lubricating oil or anti-corrosion paint is also coated on the plastic sheeting, and then the free section is placed in the PVC sleeve 8;

[0065] Step S4: placing the prestressed anchor cable 12 and grouting;

[0066] A wire ring 10 and a clamp ring 11 are set up in the pre-buried anchor cable sleeve 4, and a grouting pipe 13 is installed in the pre-buried anchor cable sleeve 4, and the end of the prestressed anchor cable 12 is welded to the guide cap 14;

[0067] Drill anchor holes 18 and clean anchor holes 18 according to the positions of pre-buried anchor cable sleeves 4, place pre-stressed anchor cables 12 in anchor holes 18, and set up pre-stressed anchor cables 12 through wire rings 10 and clamp rings 11, and then pour cement mortar 17 into the pre-buried anchor cable sleeves 4 through grouting pipes 13;

[0068] Step S5: pouring the pedestal;

[0069] According to the position of the prestressed anchor cable 12, the concrete pedestal steel mesh 7 is implanted into the retaining pile 1, holes are reserved, and the pedestal concrete 3 is cast;

[0070] Step S6: tensioning and locking the prestressed anchor cable 12;

[0071] The prestressed anchor cable 12 is tensioned 1 to 2 times, tensioned, and over-tensioned, and the prestressed anchor cable (12) is locked by a matching fixed anchor 9;

[0072] Step S7: Anchor sealing and excavation of lower earthwork;

[0073] Anchor steel bars 16 are implanted in the pedestal concrete 3, and anchor concrete 15 is poured. After the concrete reaches a certain strength, the lower part of the foundation pit is excavated.

[0074] In step S1, when the site conditions are met, a rotary drilling mechanical hole-forming process is used when the site is cleaned, and the retaining pile 1 is constructed by pile separation, and the adjacent pile hole-forming construction is continued after the concrete is finally set. The top of the retaining pile 1 is fully flooded with slurry, and the flooding height is not less than 500mm. The concrete strength grade of the retaining pile 1 is C30, the pile diameter is 1000mm, the pile spacing is 1500mm, and the cross-section of the crown beam 2 is 1000mm×1000mm.

[0075] The distance from the end of the grouting pipe 13 to the bottom of the anchor hole 18 is 200mm, and M30 cement mortar 17 is used for grouting, with a water-cement ratio of 0.4, a cement-sand ratio of 1.0, and a cement strength grade of 42.5. During construction, the prestressed anchor cable is located in the middle of the anchor hole, the drilling depth exceeds the designed length of the prestressed anchor cable by 500mm, and a 500mm sediment section is left at the bottom of the hole.

[0076] During grouting, the thickness of the cement mortar 17 protective layer around the anchor cable in the anchoring section should not be less than 20 mm.

[0077] Furthermore, it can also be considered in the example that in the step S2, before pouring the crown beam 2, the floating slurry is chiseled off, the residue, floating soil and accumulated water on the pile top are cleaned, the pile is roughened and cleaned, and the main reinforcement of the retaining pile 1 is anchored into the crown beam 2, and the anchoring length is not less than the anchoring length of the tensioned reinforcement;

[0078] The excavation of the foundation pit is divided into sections and symmetrically excavated according to the excavation plan. The principle of anchoring as you dig is followed. After the excavation of the earthwork, the concrete is sprayed between the piles and the prestressed anchor cables are arranged in time.

[0079] 100mm thick soil is excavated between the piles, and then the steel mesh 5 is erected, the transverse reinforcement 6 is implanted, and then 50mm thick pile protection concrete is sprayed. The steel mesh 5 is first-class steel with a diameter of 8mm and a spacing of 200×200mm. The transverse reinforcement 6 is third-class steel with a diameter of 16mm. The concrete between the piles is early-strength sprayed concrete with strength grade C25.

[0080] Furthermore, it can also be considered in the example that the cement mortar 17 and the pedestal concrete 3 have strengths of 25 MPa and 20 MPa respectively, and tensioning can be performed only after reaching 80% of the design strength.

[0081] Before the prestressed anchor cable 12 is formally tensioned, 0.1 to 0.2 times the design value of the axial tension of the anchor cable is taken for pre-tensioning 1 to 2 times to make the cable body completely straight and the contact of each part is close.

[0082] Tensioning equipment and instruments are used during tensioning, including jacks, oil pumps, grouting pumps, etc.

[0083] The method of overall tensioning and locking of the steel strand bundle is adopted. Before locking, the anchor cable is over-tensioned with a test value of not less than 1.4 times the design value of the anchor cable axial tension. When locking, the prestress loss during the locking process is considered, and the locking value is 1.1 to 1.5 times the design value.

[0084] The matching shaped anchor 9 has the function of compensating tension and relaxation, and 100 mm of the prestressed anchor cable 12 is retained from the matching shaped anchor 9.

[0085] The above embodiments describe the present invention in detail, but the above contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of application of the present invention shall still fall within the scope of the patent coverage of the present invention.

Claims

1. A pile-anchor support structure for prestressed anchor cable tensioning on a concrete pedestal, comprising a retaining pile (1), a cap beam (2) being connected to the upper part of the retaining pile (1), characterized in that: The main reinforcement of the retaining pile (1) is welded with a pre-buried anchor cable sleeve (4), and the retaining pile (1) is laterally provided with a lateral steel mesh (5) and transverse tensioning bars (6); A prestressed anchor cable (12) is placed in the pre-buried anchor cable sleeve (4) through an anchor hole (18) and then grouting is performed, the prestressed anchor cable (12) passes through the retaining pile (1), and the end of the prestressed anchor cable (12) is fixedly connected to a guide cap (14); A concrete pedestal steel mesh (7) is implanted in the retaining pile (1) near the front end of the prestressed anchor cable (12), and concrete is poured to form a pedestal (3); It also comprises a matching fixed anchor (9), which, after locking the prestressed anchor cable (12), implants anchor steel bars (16) in the pedestal (3) and pours anchor concrete (15).

2. A pile-anchor support structure for prestressed anchor cable tensioning on a concrete pedestal according to claim 1, characterized in that: The prestressed anchor cable (12) is divided into a free section and an anchoring section, and the free section is placed in a PVC sleeve (8).

3. A pile-anchor support structure for prestressed anchor cable tensioning on a concrete pedestal according to claim 2, characterized in that: The PVC sleeve (8) has no joint.

4. A pile-anchor support structure for prestressed anchor cable tensioning on a concrete pedestal according to claim 2 or 3, characterized in that: A grouting pipe (13) is installed in the pre-buried anchor cable casing (4), and the prestressed anchor cable (12) is installed through a wire ring (10) and a tightening ring (11) inside the pre-buried anchor cable casing (4).

5. A pile-anchor support structure for prestressed anchor cable tensioning on a concrete pedestal according to claim 4, characterized in that: The wire rack (10) and the clamp ring (11) on the anchoring section are arranged at intervals.

6. A pile-anchor support structure for prestressed anchor cable tensioning on a concrete pedestal according to claim 5, characterized in that: The wire-hanging ring (10) and the clamping ring (11) of the anchoring section are arranged at intervals of 1 m, and the free section is provided with a wire-hanging ring (10) every 3 m.

7. A pile-anchor support structure for prestressed anchor cable tensioning on a concrete pedestal according to claim 6, characterized in that: The prestressed anchor cable (12) is made of 7 steel wires twisted into a standard steel strand.

8. The pile-anchor support structure for prestressed anchor cable tensioning on a concrete pedestal according to claim 1, characterized in that: The concrete pedestal steel mesh (7) is arranged in 4 layers, with a layer spacing of 100m, and the depth of the steel mesh embedded in the surrounding pile (1) is not less than 250mm.

9. The pile-anchor support structure for prestressed anchor cable tensioning on a concrete pedestal according to claim 1, characterized in that: The length of the anchor steel bar (16) implanted in the pedestal (3) is not less than 250 mm, and the anchor steel bar (16) is a single layer with a spacing of 80 mm.

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