Prestressed anchor rod anti-floating structure and construction method thereof

Abstract

The anti-floating structure of the pre-stressed anchor rod comprises the pre-stressed anchor rod and a bottom plate, and the pre-stressed anchor rod comprises an anchor rod body and a rib body; the device further comprises an anchor rod connecting device, the anchor rod connecting device comprises a first plate component, a second plate component and a connecting piece, and the second plate component is located above the first plate component. The first plate component is located in the anchor rod body, the second plate component is located in the bottom plate, one part of the connecting piece is located in the anchor rod body, and one part of the connecting piece is located in the bottom plate; an anchorage device is arranged above the second plate component, the rib body penetrates through the first plate component and the second plate component, and the top end of the rib body is fixedly connected with the anchorage device; the top ends of the anchorage devices and the top ends of the rib bodies are located in the bottom plate. The invention further relates to a construction method of the anti-floating structure. The top of the anchor rod can be effectively protected against local compression damage, the elevation control requirement for the top of the anchor rod body is lowered, and the construction efficiency and quality can be improved.

Description

Technical Field

[0001] The present invention relates to a prestressed anchor rod anti - floating structure and its construction method, belonging to the technical field of anti - floating structures for building underground structures. Background Art

[0002] Most basements have anti - floating problems. According to the provisions of the "Technical Standard for Anti - floating of Building Engineering" JGJ476 - 2019: For projects with anti - floating design grades of Class A and Class B, the design is carried out without cracks, and prestressed anti - floating anchor rods need to be used. The prestressed anti - floating anchor rods can use steel strands or high - strength deformed steel bars as prestressed tendon bodies.

[0003] Existing Patent 1 (publication number CN214993801U) discloses a prestressed anti - floating anchor rod technology that completes tensioning and locking before the basement floor slab is poured. It realizes the connection and anchoring of the anchor rod and the floor slab (basement floor slab) by setting a prestress transfer device at the top of the anchor rod. During the tensioning process, the top stability of the anchor rod is poor, and the top of the anchor rod is subjected to a large concentrated force. When the applied prestress is too large or the strength of the top of the anchor rod is insufficient, it is easy to cause local crushing damage at the top of the anchor rod. To solve this problem, it is often necessary to set up spiral steel bars and other strengthening structures at the top of the anchor rod to improve its compressive bearing capacity. Existing Patent 2 (publication number CN115538430A) discloses a prestressed anti - floating anchor rod solution with spiral steel bars set at the top of the anchor rod body, thereby improving the compressive strength at the top of the anchor rod body.

[0004] In addition, in the solution of Existing Patent 1, according to the design of this anti - floating structure, the elevation of the top of the anchor rod body must be accurately controlled to ensure that after the prestress transfer device and the anchor are installed at the top of the anchor rod body, the entire prestress transfer device, the anchor, and the tendon body are all at the internal set elevation of the basement floor slab, avoiding the exposure of the anchor and the tendon body on the upper surface of the basement floor slab; at the same time, if the elevation of the prestress transfer device is lower than the set elevation, it will also affect the anchoring connection bearing capacity between the anchor rod and the basement floor slab. Accurately controlling the elevation of the top of the anchor rod body during the construction of the anchor rod is not conducive to improving the construction efficiency and increases the workload of construction workers. Summary of the Invention

[0005] In order to overcome the problems existing in the prestressed anchor rod anti - floating structure in the prior art, the present invention provides a prestressed anchor rod anti - floating structure and its construction method, which not only reduces the requirements for the elevation of the top of the anchor rod, but also improves the connection integrity between the anchor rod and the floor slab, and is conducive to preventing or reducing the situation of the top of the anchor rod being damaged by tensioning. The specific technical solutions are as follows.

[0006] A prestressed anchor rod anti - floating structure, comprising a prestressed anchor rod and a floor slab. The prestressed anchor rod includes an anchor rod body and a tendon body. The lower end of the tendon body is located inside the anchor rod body. It is characterized in that:

[0007] It also includes an anchor rod connecting device, which includes a first plate component, a second plate component and a connecting piece connecting the first plate component and the second plate component, the second plate component is located above the first plate component; the first plate component is located inside the anchor rod body, the second plate component is located inside the base plate, a part of the connecting piece is located inside the anchor rod body, and a part of the connecting piece is located inside the base plate; an anchor is arranged above the second plate component, the tendon passes through the first plate component and the second plate component, and the top end of the tendon is fixedly connected to the anchor; the anchor and the top end of the tendon are both located inside the base plate.

[0008] In the above scheme, the top of the tendon of the prestressed anchor is fixed to the second plate component of the anchor connection device through an anchor. The construction of the prestressed anchor and the prestressing are independent of the base plate. After the prestressing is completed, the basement basement can be constructed as a whole, avoiding the cross-construction of the prestressed anchor and the basement basement. With the above technical scheme, there is no need to accurately control the elevation of the top of the anchor body, and only the elevation of the second plate component of the anchor connection device needs to be adjusted, which greatly simplifies the construction process and reduces the workload of construction personnel; at the same time, the first plate component of the anchor connection device and a part of the connector are located inside the top of the anchor body, which can diffuse the pressure of the anchor on the top of the anchor body during prestressing, which is stronger and more stable than the spiral tendons in the prior art, preventing the anchor body from being damaged when the tendon body is prestressed.

[0009] Furthermore, the first plate component and the second plate component are circular, square or polygonal. The first plate component and the second plate component are both provided with through holes for the ribs to pass through.

[0010] Furthermore, the connecting member is a cylindrical structure, the extension direction of the cylindrical structure is parallel to the extension direction of the anchor body, the tendon body passes through the cylindrical structure, and the outer diameter of the second plate component is larger than the diameter of the cylindrical structure. The cross-section of the cylindrical structure is circular, rectangular or polygonal. The cylindrical structure can better withstand prestress, so that the first plate component or the second plate component is evenly stressed; the second plate component can be better anchored in the base plate, and the buoyancy of the base plate is transferred to the prestressed anchor. Preferably, a through hole is provided on the side wall of the cylindrical structure. Through the through hole, part of the grouting material of the anchor body can be injected into the inside of the cylindrical structure, and at the same time, the concrete of the basement floor can also be filled into the inside of the cylindrical structure through the through hole, thereby improving the integrity of the anchor connection device and the base plate.

[0011] Furthermore, bolts are fixedly arranged on the outer wall of the cylindrical structure, which are beneficial to increase the bite bonding effect between the cylindrical structure and the anchor body (anchor slurry).

[0012] Further, the connecting member is a plurality of columns, and the cross-section of the column is circular, square, T-shaped, oval, trapezoidal or polygonal. To ensure balanced stress, usually more than three columns are evenly distributed.

[0013] Further, the connecting member further includes a cross bar connecting the two columns. The connecting member formed by the column and the cross bar constitutes a hollow bracket, which has good stability, and at the same time ensures that the slurry of the anchor body and the concrete of the bottom plate can be fully filled in the space between the columns. Preferably, reinforcing rib plates are provided at the top and bottom ends of the column.

[0014] Further, the reinforcing body is made of steel strand or deformed steel bar. The steel strand, as a prestressed reinforcing body, has low cost, simple tensioning and easy operation; the deformed steel bar has high strength and good tensile performance, which is beneficial to saving materials and cost.

[0015] Based on the same inventive concept, the present invention also relates to a construction method of the above-mentioned prestressed anchor anti-floating structure, which mainly includes the following steps:

[0016] 1), Drilling, and placing the reinforcing body into the anchor hole;

[0017] 2), Placing the anchor connecting device, and allowing the reinforcing body to penetrate through the first plate member and the second plate member of the anchor connecting device;

[0018] 3), Using the elevation adjustment auxiliary device to fix the elevation of the anchor connecting device;

[0019] 4), Injecting slurry into the anchor hole to form an anchor body;

[0020] 5), After the anchor body reaches the design strength, placing the anchor at the upper part of the second plate member, and performing prestress tensioning on the reinforcing body. After tensioning, locking the reinforcing body by using the anchor;

[0021] 6), Constructing the bottom plate, and accommodating the second plate member, the anchor and the top end of the reinforcing body inside the bottom plate.

[0022] The present invention has the characteristics of simple construction, reliable quality and good economy. Compared with the prior art, it has the following beneficial effects:

[0023] 1. By embedding the anchor connecting device at the top of the anchor body, the anchor body can be better connected with the bottom plate as a whole;

[0024] 2. The anchor connecting device is embedded into the top of the anchor body by a certain length, and the concentrated force at the top of the anchor in the traditional method is dispersed during the tensioning process, which can effectively protect the top of the anchor from being damaged by local compression;

[0025] 3. The anchor rod connecting device is embedded in the top of the anchor rod body, which can save the spiral reinforcement set at the top of the anchor rod in the traditional method, and the effect of strengthening the top of the anchor rod by embedding the anchor rod connecting device in the top of the anchor rod body is better;

[0026] 4. The requirement for controlling the elevation of the top of the anchor rod body is reduced, and the height control of the anchor rod body is more arbitrary, which is beneficial to improving the construction efficiency and reducing the workload of construction personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of the prestressed anchor rod anti-floating structure according to Embodiment 1 of the present invention;

[0028] Figure 2 is a schematic diagram of the anchor rod connecting device according to Embodiment 1 of the present invention;

[0029] Figure 3 is Figure 2 the schematic diagram of the 1-1 cross-section in;

[0030] Figure 4 is a schematic diagram of a modified example of the anchor rod connecting device according to Embodiment 1 of the present invention;

[0031] Figure 5 is a schematic diagram of the elevation adjustment auxiliary device used during the construction of the prestressed anchor rod anti-floating structure according to Embodiment 1 of the present invention;

[0032] Figure 6 is a schematic diagram of the anchor rod connecting device according to Embodiment 2 of the present invention;

[0033] Figure 7 is Figure 6 the schematic diagram of the 2-2 cross-section in;

[0034] Figure 8 is a schematic diagram of a modified example of the anchor rod connecting device according to Embodiment 2 of the present invention.

[0035] In the figure: bottom plate 1, anchor rod body 2, reinforcing body 3, anchor rod connecting device 4, first plate member 4.1, second plate member 4.2, cylindrical structure 4.3, stud 4.3.1, column 4.4, cross bar 4.5, through hole 4.6, through hole 4.7, reinforcing rib plate 4.8, anchor hole 5, elevation adjustment auxiliary device 6, support member 6.1, adjustment sleeve 6.2, screw rod 6.3, anchor 7, waterproof layer 8, foundation 9, cushion 10. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The present invention will be further described in detail below with reference to the accompanying drawings.

[0037] Embodiment 1

[0038] See Figures 1-3A prestressed anchor anti-floating structure comprises a prestressed anchor and a base plate 1, wherein the prestressed anchor comprises an anchor body 2 and a tendon 3, wherein the lower end of the tendon 3 is located inside the anchor body 2; an anchor connecting device 4 is also included, wherein the anchor connecting device 4 comprises a first plate component 4.1, a second plate component 4.2 and a connecting piece connecting the first plate component 4.1 and the second plate component 4.2, wherein the second plate component 4.2 is located above the first plate component 4.1; the first plate component 4.1 is located inside the anchor body 2, the second plate component 4.2 is located inside the base plate 1, a part of the connecting piece is located inside the anchor body 2, and a part of the connecting piece is located inside the base plate 1; an anchor 7 is arranged above the second plate component 4.2, the tendon 3 passes through the first plate component 4.1 and the second plate component 4.2, and the top end of the tendon 3 is fixedly connected to the anchor 7; the anchor 7 and the top end of the tendon 3 are both located inside the base plate 1. Typically, a cushion layer 10 is laid on the foundation 9 , a waterproof layer 8 is laid on the cushion layer 10 , and a bottom plate 1 in the form of reinforced concrete is formed above the waterproof layer 8 .

[0039] The first plate member 4.1 and the second plate member 4.2 may be in a circular, square or polygonal shape. The first plate member 4.1 and the second plate member 4.2 are both provided with a through hole 4.6 for the reinforcement body 3 to pass through.

[0040] The connecting piece is a cylindrical structure 4.3, the extension direction of the cylindrical structure 4.3 is parallel to the extension direction of the anchor body 2, the tendon 3 passes through the cylindrical structure 4.3, and the outer diameter of the second plate component 4.2 is greater than the diameter of the cylindrical structure 4.3. The cross-section of the cylindrical structure 4.3 is circular, rectangular or polygonal. The cylindrical structure 4.3 can better withstand prestress, so that the first plate component 4.1 or the second plate component 4.2 is evenly stressed; the second plate component 4.2 can be better anchored in the base plate 1, and the buoyancy of the base plate 1 is transferred to the prestressed anchor. Preferably, a through hole 4.7 is provided on the side wall of the cylindrical structure 4.3. Through the through hole 4.7, the grouting material of part of the anchor body 2 can be injected into the cylindrical structure 4.3, and at the same time, the concrete of the basement floor 1 can also be filled into the cylindrical structure 4.3 through the through hole 4.7, so as to improve the integrity of the anchor connection device 4 and the base plate 1.

[0041] like Figure 4 As shown, preferably, a stud 4.3.1 is fixedly arranged on the outer wall of the cylindrical structure 4.3. The stud 4.3.1 is helpful to increase the bite bonding effect between the cylindrical structure 4.3 and the anchor body 2 (anchor slurry).

[0042] Furthermore, the tendon 3 is made of steel strand or threaded steel. Steel strand as prestressed tendon has low cost, simple tensioning, easy operation and low cost; threaded steel has high strength and good tensile properties, which is conducive to saving materials and cost.

[0043] See alsoFigures 1-5 , the construction method of the above prestressed anchor anti-floating structure mainly includes the following steps:

[0044] 1), Drill the anchor hole 5 at the set position of the foundation 9, and place the tendon body 3 into the anchor hole 5;

[0045] 2), Place the anchor rod connecting device 4, and let the tendon body 3 pass through the first plate member 4.1 and the second plate member 4.2 of the anchor rod connecting device 4;

[0046] 3), Use the elevation adjustment auxiliary device 6 to fix the elevation of the anchor rod connecting device 4;

[0047] 4), Grout into the anchor hole 5 to form the anchor rod body 2, and also inject a certain amount of the slurry of the anchor rod body 2 into the interior of the cylindrical structure 4.3 through the through hole 4.7;

[0048] 5), After the anchor rod body 2 reaches the design strength, place the anchor 7 above the second plate member 4.2, and perform prestress tensioning on the tendon body 3. After tensioning, lock the tendon body 3 with the anchor 7;

[0049] 6), Construct the bottom plate 1, and accommodate the second plate member 4.2, the anchor 7 and the top end of the tendon body 3 inside the bottom plate 1. Among them, the concrete of the bottom plate 1 will also fill the interior of the cylindrical structure 4.3 through the through hole 4.7.

[0050] As Figure 5 shown, the elevation adjustment auxiliary device 6 includes a support member 6.1 and a height adjustment mechanism. The height adjustment mechanism includes an adjustment sleeve 6.2 and two screw rods 6.3. The two screw rods 6.3 are respectively threadedly connected to both ends of the adjustment sleeve 6.2, and the external threads of the two screw rods 6.3 have opposite helix directions. When the constructor rotates the adjustment sleeve 6.2, the overall length of the two screw rods 6.3 can be adjusted, so as to realize the adjustment of the height of the support member 6.1, and the support member 6.1 abuts against the lower surface of the second plate member 4.2. Those skilled in the art can understand that: other structural forms of the elevation adjustment auxiliary device 6 can also be used, as long as the anchor rod connecting device 4 (the second plate member 4.2) can be positioned at the set height.

[0051] Among them, the construction of the anchor rod body 2 and the tensioning process of the tendon body 3 both belong to the prior art.

[0052] In this embodiment, the top end of the tendon body 3 of the prestressed anchor rod is fixed to the second plate member 4.2 of the anchor rod connecting device 4 through the anchor 7. The construction and prestress tensioning of the prestressed anchor rod have nothing to do with the basement floor 1. After the prestress tensioning is completed, the basement floor 1 can be constructed as a whole, avoiding the cross-operation of the construction of the prestressed anchor rod and the basement floor 1. By adopting this embodiment, it is not necessary to accurately control the elevation of the top of the anchor rod body 2, and only the elevation of the second plate member 4.2 of the anchor rod connecting device 4 needs to be adjusted, which greatly simplifies the construction process and reduces the workload of the construction personnel. At the same time, a part of the first plate member 4.1 of the anchor rod connecting device 4 and the connecting member are located inside the top of the anchor rod body 2, which can play the role of the spiral steel bar in the prior art, that is, improve the compressive bearing capacity of the top of the anchor rod body 2 and prevent the anchor rod body 2 from being damaged when prestress tensioning is applied to the tendon body 3.

[0053] The anti-floating principle of the anti-floating structure in this embodiment is as follows: when the basement floor 1 is subjected to the upward buoyancy force of groundwater, the basement floor 1 transfers the upward buoyancy force to the second plate member 4.2 of the anchor rod connecting device 4 and the cylindrical structure 4.3. The upward force received by the second plate member 4.2 is directly transferred to the anchor 7 and the tendon body 3, and the tendon body 3 transfers the upward force to the anchor rod body 2. The anchor rod body 2 is anchored to the foundation 9 to resist (offset) the upward force received. That is to say, the buoyancy force received by the basement floor 1 is finally transferred to the anchor rod body 2 and the foundation 9. Since the tendon body 3 is in a stretched state after prestress tensioning, the retraction tendency (trend) of the tendon body 3 makes the anchor rod body always in a compressed state, so that the anchor rod body is not easy to appear cracks, meeting the requirements of relevant standards.

[0054] On the one hand, the second plate member 4.2 of the anchor rod connecting device 4 serves as the supporting surface of the anchor 7, and on the other hand, it plays the role of being fixed to the basement floor 1 and transferring the anti-buoyancy force.

[0055] Embodiment 2

[0056] See Figures 6-7 , the difference between Embodiment 2 and Embodiment 1 is that the connecting member is not a cylindrical structure, but includes a plurality of columns 4.4, and the cross-section of the columns 4.4 is circular, square, T-shaped, oval, trapezoidal or polygonal, etc. In order to ensure balanced stress, usually more than three columns 4.4 need to be evenly distributed. As Figure 8 shown, preferably, the connecting member further includes a cross bar 4.5 connecting two columns 4.4. The connecting member formed by the columns 4.4 and the cross bar 4.5 constitutes a hollow bracket, which has good stability and at the same time ensures that the slurry of the anchor rod body 2 and the concrete of the basement floor 1 can fully fill the space between the columns 4.4. Preferably, reinforcing rib plates 4.8 are provided at the top and bottom ends of the columns 4.4.

[0057] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention is not limited to the specific embodiments described above. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit of the present invention and the scope protected by the claims. All of these fall within the protection scope of the present invention.

Claims

1. A prestressed anchor rod anti - floating structure, comprising a prestressed anchor rod and a bottom plate (1). The prestressed anchor rod includes an anchor rod body (2) and a tendon body (3). The lower end of the tendon body (3) is located inside the anchor rod body (2), and it is characterized in that: It further includes an anchor rod connecting device (4). The anchor rod connecting device (4) includes a first plate member (4.1), a second plate member (4.2), and a connecting member connecting the first plate member (4.1) and the second plate member (4.2). The second plate member (4.2) is located above the first plate member (4.1); the first plate member (4.1) is located inside the anchor rod body (2), the second plate member (4.2) is located inside the bottom plate (1), a part of the connecting member is located inside the anchor rod body (2), and a part of the connecting member is located inside the bottom plate (1); an anchor (7) is arranged above the second plate member (4.2). The tendon body (3) passes through the first plate member (4.1) and the second plate member (4.2), and the top end of the tendon body (3) is fixedly connected to the anchor (7); both the anchor (7) and the top end of the tendon body (3) are located inside the bottom plate (1).

2. The anti-floating structure of a prestressed anchor rod according to claim 1, characterized in that, The first plate member (4.1) and the second plate member (4.2) are circular, square or polygonal.

3. A prestressed anchor anti-floating structure according to claim 1 or 2, characterized in that, The connecting member is a cylindrical structure (4.3). The extending direction of the cylindrical structure (4.3) is parallel to the extending direction of the anchor rod body (2). The tendon body (3) passes through the cylindrical structure (4.3), and the outer diameter of the second plate member (4.2) is greater than the diameter of the cylindrical structure (4.3).

4. A prestressed anchor rod anti-floating structure according to claim 3, characterized in that, Through holes (4.7) are arranged on the side wall of the cylindrical structure (4.3).

5. A prestressed anchor anti-floating structure according to claim 3, characterized in that, Studs (4.3.1) are fixedly arranged on the outer wall of the cylindrical structure (4.3).

6. The anti - floating structure of a prestressed anchor rod according to claim 1 or 2, characterized in that, The connecting member is several columns (4.4). The cross - section of the columns (4.4) is circular, square, T - shaped, oval, trapezoidal or polygonal.

7. A prestressed anchor anti - floating structure according to claim 6, characterized in that, The connecting member further includes a cross bar (4.5) connecting the two columns (4.4).

8. A prestressed anchor anti-floating structure according to claim 6, characterized in that, Reinforcing rib plates (4.8) are arranged at both the top end and the bottom end of the columns (4.4).

9. The anti-floating structure of a prestressed anchor rod according to claim 1, characterized in that, The tendon body (3) is made of steel strand or deformed steel bar.

10. A construction method of the prestressed anchor rod anti - floating structure according to any one of the above - mentioned claims, mainly including the following steps: 1). Drilling a hole and placing the tendon body (3) into the anchor hole (5); 2). Placing the anchor rod connecting device (4) and letting the tendon body (3) pass through the first plate member (4.1) and the second plate member (4.2) of the anchor rod connecting device (4); 3). Using the elevation adjustment auxiliary device (6) to fix the elevation of the anchor rod connecting device (4); 4). Grouting into the anchor hole (5) to form the anchor rod body (2); 5). After the anchor rod body (2) reaches the designed strength, placing the anchor (7) above the second plate member (4.2), and performing prestress tensioning on the tendon body (3). After tensioning, locking the tendon body (3) with the anchor (7); 6) Construct the bottom plate (1) and accommodate the top ends of the second plate member (4.2), the anchor (7), and the reinforcing body (3) inside the bottom plate (1).

Images