A locking method for pressure-type anti-floating piles inside a foundation

Abstract

The present application relates to a method for locking a pressure-type anti-floating pile inside a foundation. The locking method is to set an "I-shaped" locking bracket formed by a lower pressure plate, a filled steel pipe and a stress anchor plate whose area meets the anti-floating requirements at the top of the anti-floating pile. The unbonded steel strand passes through the center of the locking bracket, and the locking bracket is locked on the top of the pile by applying prestress with an anchor. After the cushion layer and waterproofing construction are completed, it is poured inside the foundation. For pressure-type prestressed anti-floating anchor rods, the unbonded steel strand is generally passed through the foundation and locked on the foundation plate, which is difficult to construct and has poor waterproofing effect, and is prone to cause leakage problems on the foundation bottom plate. However, the present application locks the unbonded steel strand on the top of the pile through the "I-shaped" locking bracket on the top of the pile, so that waterproofing construction can be carried out around the steel pipe of the locking bracket, which is easy to ensure quality and has good waterproofing effect, and can well solve the foundation waterproofing leakage problem caused by the locking of the unbonded steel strand.

Description

Technical Field

[0001] The present application relates to the technical field of pressure-type anti-floating piles, and in particular to a method for locking pressure-type anti-floating piles inside a foundation. Background Art

[0002] At present, the main methods for solving the anti-floating problem of underground structures include anti-floating plate method, weight method, drainage pressure limiting method, water isolation pressure control method and water discharge pressure reduction method, anti-floating anchor rod method, anti-floating pile method, etc. In actual engineering, the anti-floating pile method or anti-floating anchor rod method is the most commonly used method to solve the foundation anti-floating and foundation anti-floating problems. Since the implementation of the "Technical Standard for Anti-Floating of Construction Engineering" (JGJ476-2019) on March 1, 2020, the design requirements for anti-floating piles or anti-floating anchor rods in various provinces across the country have become more stringent, and some provinces have required the use of pressure-type anti-floating design solutions. For pressure-type anti-floating piles or anti-floating anchor rods, the main reinforcement generally uses unbonded steel strands, and the unbonded steel strands are tensioned and locked on the foundation slab, which makes the construction difficult, the waterproof effect is poor, and the foundation slab is prone to leakage. At the same time, the pre-locking force will be lost over time.

[0003] At present, pressure-type anti-floating anchors are used. However, due to the small area of ​​the pressure plate and the low strength of the anchor grouting body, the pressure provided by the pressure plate is small, and the bearing capacity may not meet the design requirements. Therefore, its application in actual projects is increasingly restricted.

[0004] Through the analysis of the above problems, it is urgent to develop a new locking method for pressure-type anti-floating piles, which has the advantages of convenient waterproof construction, reliable quality, good waterproof effect, and stable pre-locking force. Summary of the invention

[0005] The present application provides a method for locking pressure-type anti-floating piles inside a foundation, which can overcome the problems of difficulty in foundation waterproofing construction, poor waterproofing effect, and easy leakage under the existing locking method. Pressure-type anti-floating piles can use unbonded steel strands or steel strands with free sections.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] A method for locking a pressure-type anti-floating pile inside a foundation comprises the following steps: after an unbonded steel strand is inserted into a pile body, a combined component consisting of a lower pressure plate and a steel pipe is placed on the top of the pile body, and at the same time, the unbonded steel strand is vertically and centrally passed through the steel pipe, cement slurry, cement mortar, grouting material or polyurethane waterproof material is laid between the lower pressure plate and the top of the pile body, and a filling material is poured inside the steel pipe, and after the designed strength is reached, a stress-bearing anchor plate with an area meeting the anti-floating requirement is passed through the unbonded steel strand and placed on the steel pipe, at which time an "I-shaped" locking bracket consisting of a lower pressure plate, a filled steel pipe and a stress-bearing anchor plate with an area meeting the anti-floating requirement is formed on the top of the pile body, and then prestress is applied to the passed unbonded steel strand to lock the "I-shaped" locking bracket on the pile top through an anchor, and after the construction of the foundation cushion layer and the waterproof layer is completed, the bracket is poured inside the foundation, wherein the top of the pile body is arranged inside the foundation, at the bottom elevation of the cushion layer or inside the cushion layer.

[0008] The pile body has a constant diameter along the length direction, and the pile body material adopts cement paste, cement mortar or concrete; the concrete strength grade is C25-C60, the concrete slump is 120-240mm, and the pile diameter is 250-800mm.

[0009] The unbonded steel strands are evenly distributed inside the pile body and are parallel to the length direction of the pile body. At the same time, the unbonded steel strands pass through the steel pipe vertically and centrally.

[0010] The lower pressure plate is placed centrally on the top of the pile body. The lower pressure plate is a square or round steel plate with a thickness of 5 to 50 mm. A hole is reserved in the center of the steel plate. The size of the hole must meet the requirement that the unbonded steel strand can pass straight through the hole.

[0011] The lower part of the steel pipe is vertically fixed at the center of the lower pressure plate. The lower part of the steel pipe is fixed to the lower pressure plate by direct fixing or welding. The center line of the steel pipe coincides with the center line of the reserved hole in the lower pressure plate. The wall thickness of the steel pipe is 2.5 to 40 mm, and the inner diameter of the steel pipe is not less than the size of the reserved hole in the lower pressure plate.

[0012] Cement slurry, cement mortar, grouting material or polyurethane waterproof material is laid between the lower pressure plate and the top of the pile body. By laying cement slurry, cement mortar, grouting material or polyurethane waterproof material, on the one hand, the top of the pile body can be leveled, and on the other hand, the gap between the lower pressure plate and the top of the pile body can be closed, thereby playing a certain waterproof role.

[0013] The filler is concrete, cement paste, cement mortar or grouting material used to fill the inside of the steel pipe. The filler can play a waterproof role on the one hand, and can protect the unbonded steel strands in the steel pipe on the other hand.

[0014] The sizes of the anchor plate and anchor are determined according to the design requirements, and generally need to meet the shear resistance requirements and anchoring force requirements of the base plate.

[0015] A method for locking a pressure-type anti-floating pile inside a foundation includes the following construction steps:

[0016] Step 1: After the pressure-type anti-floating pile is constructed, the top of the pile body is chiseled off to protect the pile head, and the unbonded steel strands are exposed at the top of the pile;

[0017] Step 2: trim the pile top to a flat surface, and lay cement slurry, cement mortar, grouting material or polyurethane waterproof material on the top of the pile body; place the combined component consisting of the lower bearing plate and the steel pipe on the top of the pile body, and at the same time, pass the unbonded steel strand vertically through the steel pipe;

[0018] Step 3: Pour filler into the steel pipe;

[0019] Step 4: Pass the steel strands through the anchor plate with holes and place it on the combined component consisting of the lower bearing plate and the steel pipe, and apply prestress to the steel strands to tension and lock them;

[0020] Step 5: After the cushion layer and waterproofing construction are completed, pour it inside the foundation.

[0021] In summary, the present application includes at least one of the following beneficial technical effects:

[0022] 1. The use of this locking method does not affect the subsequent general contractor's foundation reinforcement binding construction, there is no cross-operation in the process, and the construction efficiency is high and the speed is fast;

[0023] 2. This locking method can greatly simplify the waterproof construction process of the general contractor, making the construction convenient and effective;

[0024] 3. Compared with the conventional locking method of locking the unbonded steel strands above the foundation slab, this locking method has more reliable waterproofing quality, better waterproofing effect, and more stable pre-locking force. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the pile body exposed after the pile head is chiseled;

[0026] Figure 2 It is a schematic diagram of the lower bearing plate and the steel pipe composite component being vertically fixed on the top of the pile body;

[0027] Figure 3 It is a schematic diagram of steel pipe pouring filling material;

[0028] Figure 4 It is a schematic diagram of tensioning and locking of unbonded steel strands;

[0029] Figure 5 This is a schematic diagram of the position relationship between the "I-shaped" locking bracket and the foundation cushion and waterproof layer Figure 1

[0030] Figure 6 This is a schematic diagram of the position relationship between the "I-shaped" locking bracket and the foundation cushion and waterproof layer Figure 2

[0031] Explanation of the reference numerals in the accompanying drawings: 1-pile body, 2-unbonded steel strand, 3-cement slurry, cement mortar, grouting material or polyurethane waterproof material, 4-lower bearing plate, 5-steel pipe, 6-filling material, 7-anchor plate, 8 anchor, 9-cushion, 10-waterproof layer, 11-foundation. DETAILED DESCRIPTION

[0032] The following is combined with Figure 1-6 This application is described in further detail.

[0033] The embodiment of the present application discloses a method for locking a pressure-type anti-floating pile inside a foundation.

[0034] Reference Figure 1-Figure 6 The components include: pile body 1, unbonded steel strand 2, grouting material or flexible polyurethane waterproof material 3, lower bearing plate 4, steel pipe 5, filling material 6, anchor plate 7, anchor 8, cushion layer 9, waterproof layer 10, foundation 11.

[0035] Reference Figure 1 The material of the pile body 1 is cement paste, cement mortar or concrete; the concrete strength grade is C25-C60, the concrete slump is 120-240mm, and the pile diameter is 250-800mm;

[0036] Reference Figure 2 , cement slurry, cement mortar, grouting material or polyurethane waterproof material 3 is laid between the lower pressure plate 4 and the top of the pile body 1, the lower part of the steel pipe 5 is vertically fixed to the center of the lower pressure plate 4, and the lower part of the steel pipe 5 is fixed to the lower pressure plate 4 by direct fixing or welding. The center line of the steel pipe 5 coincides with the center line of the reserved hole of the lower pressure plate 4, and then the combined component composed of the lower pressure plate 4 and the steel pipe 5 is vertically placed on the top of the pile body 1, and the unbonded steel strand 2 passes through the steel pipe 5 vertically and in the center. The lower pressure plate 4 is a square or round steel plate with a thickness of 5 to 50 mm. A hole is reserved in the center of the steel plate. The size of the hole must meet the requirement that the unbonded steel strand 2 passes straight through the hole. The wall thickness of the steel pipe 5 is 2.5 to 40 mm, and the inner diameter of the steel pipe 5 is not less than the size of the hole reserved in the lower pressure plate 4;

[0037] Reference Figure 3 , pouring a filler 6 into the steel pipe 5, the filler 6 can be concrete, cement paste, cement mortar or grouting material;

[0038] Reference Figure 4, pass the anchor plate 7 through the unbonded steel strand 2 and place it on the steel pipe 5, then apply prestress on the unbonded steel strand 2 and lock the "I-shaped" locking bracket on the pile top through the anchor 8;

[0039] Reference Figure 5 The top of the pile body 1 is anchored into the foundation 11, and the foundation 11 is poured after the cushion layer 9 and the waterproof layer 10 are constructed.

[0040] Reference Figure 6 The top of the pile body 1 is set at the bottom elevation of the cushion layer 9, and the foundation 11 is poured after the cushion layer 9 and the waterproof layer 10 are completed.

[0041] A method for locking a pressure-type anti-floating pile inside a foundation includes the following construction steps:

[0042] Step 1: After the pressure-type anti-floating pile is constructed, the top of the pile body 1 is chiseled off to protect the pile head, and the unbonded steel strand 2 is exposed at the top of the pile;

[0043] Step 2: trim the pile top into a flat surface, and lay cement slurry, cement mortar, grouting material or polyurethane waterproof material 3 on the top of the pile body 1; place the combined component consisting of the lower bearing plate 4 and the steel pipe 5 on the top of the pile body 1, and at the same time, the unbonded steel strand 2 passes vertically through the steel pipe 5;

[0044] Step 3: Filling the steel pipe 5 with filler 6;

[0045] Step 4: Pass the anchor plate 7 with holes through the steel strand 2 and place it on the combined component composed of the lower pressure plate 4 and the steel pipe 5, and apply prestress to the steel strand 2 to tension and lock it;

[0046] Step 5: After the cushion layer 9 and the waterproof layer 10 are constructed, they are poured inside the foundation 11 .

[0047] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application, as well as anti-floating piles formed by the upper steel strands of the pile body being free sections and the lower steel strands being anchoring sections, should be covered within the protection scope of the present application.

Claims

1. A method for locking a pressure-type anti-floating pile inside a foundation, characterized in that: After the construction of the pressure-type anti-floating pile is completed, the pile head is cut to expose the unbonded steel strand (2) from the center of the pile body (1), the pile head is trimmed and leveled, and a layer of cement slurry, cement mortar, grouting material or polyurethane waterproof material (3) is laid. The combined component consisting of the lower pressure plate (4) and the steel pipe (5) is placed in the middle of the top of the pile body (1), and the unbonded steel strand (2) is passed through the middle of the steel pipe (5). Then, the filling material (6) is poured into the steel pipe (5). After the steel pipe (5) reaches the designed strength, the load-bearing anchor plate (7) with an area that meets the anti-floating requirements is passed through the unbonded steel strand (2) and placed on the steel pipe (5). At this time, the top of the pile body (1) forms a lower bearing plate. An "I-shaped" locking bracket is composed of a pressure plate (4), a filled steel pipe (5) and a stress-bearing anchor plate (7) whose area meets the anti-floating requirements. Then, prestress is applied to the unbonded steel strand (2) that passes through, and the "I-shaped" locking bracket is locked on the top of the pile through an anchor (8). After the construction of the foundation cushion layer (9) and the waterproof layer (10) is completed, the bracket is poured inside the foundation (11); wherein the top elevation of the pile body (1) is set inside the foundation (11), the bottom elevation of the cushion layer (9) or inside the cushion layer (9) according to design requirements; and the filling material (6) is concrete, cement slurry, cement mortar or grouting material to fill the inside of the steel pipe (5).

2. The method for locking a pressure-type anti-floating pile inside a foundation according to claim 1, characterized in that: The pile body (1) has a constant diameter along the length direction. The pile body (1) is made of cement paste, cement mortar or concrete; the concrete strength grade is C25-C60, the concrete slump is 120-240 mm, and the pile diameter is 250-800 mm.

3. The method for locking a pressure-type anti-floating pile inside a foundation according to claim 1, characterized in that: The unbonded steel strands (2) are evenly distributed inside the pile body (1) and are parallel to the length direction of the pile body (1). At the same time, the unbonded steel strands (2) pass through the steel pipe (5) vertically and in the center.

4. The method for locking a pressure-type anti-floating pile inside a foundation according to claim 1 is characterized in that: The lower pressure plate (4) is centrally placed on the top of the pile body (1). The lower pressure plate (4) is a square or round steel plate with a thickness of 5 to 50 mm. A hole is reserved in the center of the steel plate. The size of the hole must meet the requirement that the unbonded steel strand (2) can pass straight through the hole.

5. The method for locking a pressure-type anti-floating pile inside a foundation according to claim 1 is characterized in that: The lower part of the steel pipe (5) is vertically fixed to the center of the lower pressure plate (4). The lower part of the steel pipe (5) is directly fixed to the lower pressure plate (4) or fixed to the lower pressure plate (4) by welding. The center line of the steel pipe (5) coincides with the center line of the reserved hole of the lower pressure plate (4). The wall thickness of the steel pipe (5) is 2.5 to 40 mm, and the inner diameter of the steel pipe (5) is not less than the size of the reserved hole of the lower pressure plate (4).

6. The method for locking a pressure-type anti-floating pile inside a foundation according to claim 1, characterized in that: Cement slurry, cement mortar, grouting material or polyurethane waterproof material (3) is laid between the lower pressure plate (4) and the top of the pile body (1).

7. The method for locking a pressure-type anti-floating pile inside a foundation according to claim 1, characterized in that: The sizes of the anchor plate (7) and the anchor (8) are determined according to design requirements.

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