Construction method of composite anchor rod anti-pulling screw pile

Abstract

The invention relates to the field of composite anti-pulling anchor rods, and discloses a construction method of a composite anchor rod anti-pulling screw pile, which comprises the following steps of: prefabricating a waterproof sleeve and a rod rib; a screw pile is poured underground, the drill conductor is inserted into the screw pile before the screw pile is solidified, it is ensured that the bottom of the drill conductor is closed, and it is ensured that the top of the drill conductor is higher than the top of the screw pile; filling materials are poured into the drill conductor with the closed bottom, then the rod rib is inserted into the drill conductor, and it is ensured that the top of the rod rib is higher than the top of the drill conductor; and waiting for solidification of the screw pile and the filling material. The external shape of the composite anchor rod anti-pulling screw pile manufactured by the embodiment of the invention is provided with threads, so that the friction force between the composite anchor rod anti-pulling screw pile and soil is increased, the anti-pulling performance is improved, and the composite anchor rod anti-pulling screw pile combines the advantages of a traditional composite anti-pulling anchor rod and a traditional screw pile.

Description

Technical Field

[0001] The invention relates to the field of composite anti-pullout anchor rods, and in particular to a construction method of composite anchor rod anti-pullout screw piles. Background Art

[0002] A composite pull-out anchor (also known as a combined pull-out anchor) is an anchor with a concrete pile body, a waterproof casing and reinforcement. The concrete pile body is a prefabricated hollow tube or a cylinder cast into the ground. The waterproof casing and the reinforcement are connected to the concrete pile body by post-cast cement slurry, such as a combined enhanced pull-out anchor device disclosed in CN211472481U. The concrete pile body and the waterproof casing form a double-layer barrier to prevent groundwater from corroding the reinforcement.

[0003] Since the outer shape of the prefabricated concrete pile body is a cylinder, the friction between the concrete pile body and the soil is small, so the pull-out resistance is poor. Summary of the invention

[0004] The purpose of the present invention is to provide a construction method of a composite anchor anti-pullout screw pile to solve the problem of how to increase the friction between the composite anti-pullout anchor and the soil and improve the anti-pulling performance of the composite anti-pullout anchor.

[0005] In order to solve the above technical problems, the present invention specifically provides the following technical solutions:

[0006] A construction method for composite anchor pull-out resistant screw piles, comprising the following steps: prefabricating a waterproof casing and rod reinforcement; casting the screw pile underground, inserting the waterproof casing into the interior of the screw pile before the screw pile solidifies, ensuring that the bottom of the waterproof casing is closed, and ensuring that the top of the waterproof casing is higher than the top of the screw pile; pouring filling material into the interior of the waterproof casing with a closed bottom, and then inserting the rod reinforcement into the interior of the waterproof casing, ensuring that the top of the rod reinforcement is higher than the top of the waterproof casing; waiting for the screw pile and the filling material to solidify.

[0007] Furthermore, the filling material is cement slurry.

[0008] Furthermore, before inserting the waterproof casing into the interior of the screw pile, the bottom of the waterproof casing is sealed in advance.

[0009] In another embodiment, after the waterproof casing is inserted into the interior of the screw pile, the bottom of the waterproof casing is closed.

[0010] Furthermore, before sealing the bottom of the waterproof casing, the concrete slurry flowing from the screw pile into the interior of the waterproof casing is removed to expose the bottom of the waterproof casing.

[0011] Furthermore, after the bottom of the waterproof casing is exposed, a sealing material is filled in the bottom of the waterproof casing to form a sealing layer that seals the bottom of the waterproof casing.

[0012] Furthermore, before inserting the waterproof casing into the interior of the screw pile, an elastic breathable member is bonded to the interior of the waterproof casing and a mud pipe is inserted at the same time, and the center of the elastic breathable member has a through hole for the mud pipe to pass through; while inserting the waterproof casing into the interior of the screw pile, the mud pipe is used to suck the concrete slurry flowing into the interior of the waterproof casing to prevent the concrete slurry from floating above the elastic breathable member; after the bottom of the waterproof casing reaches a predetermined depth, the mud pipe is pulled out, and the elastic breathable member naturally expands inward to close the through hole, thereby forming a barrier layer that prevents the concrete slurry from floating, and the sealing layer is formed above the barrier layer.

[0013] Furthermore, at least one guide is welded to the outer side of the watertight casing. When the number of the guides is greater than 1, a plurality of the guides are distributed along the axis of the watertight casing. Each of the guides includes a plurality of bends. The plurality of bends are evenly distributed around the axis of the watertight casing. The bends are in the shape of arcs or broken lines. The bends are in the same plane as the axis of the watertight casing. The bends are made of bent steel bars or steel strips. Both ends of the bends are welded to the wall of the watertight casing, and the middle end of the bends protrudes outward.

[0014] Furthermore, after the screw piles are cast underground, a foundation is constructed on the ground.

[0015] Furthermore, before constructing the foundation on the ground, a sand filling layer is formed above the screw piles so that the sand filling layer covers the tops of the screw piles, and after the foundation is formed, the sand filling layer is located between the screw piles and the foundation.

[0016] Compared with the prior art, this application has the following beneficial effects:

[0017] Provided is a construction method for composite anchor anti-pullout screw piles. The composite anchor anti-pullout screw piles manufactured by the method have threads on the outside, which increases the friction between the piles and the soil, improves the pull-out resistance, and combines the advantages of traditional composite anti-pullout anchors and screw piles. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0019] Figure 1 is a cross-sectional view of a longitudinal section of a first embodiment of the present invention;

[0020] Figure 2 is a cross-sectional view of a first embodiment of the present invention;

[0021] Figure 3 is a longitudinal cross-sectional view of a second embodiment of the present invention, showing the working process of extracting concrete slurry from the interior of the waterproof casing;

[0022] Figure 4 is a longitudinal cross-sectional view of a second embodiment of the present invention, showing the working condition of forming a sealing layer at the bottom of the waterproof casing;

[0023] The numbers in the figure represent the following:

[0024] 1-screw pile; 2-waterproof casing; 21-plug; 22-mud pipe; 23-elastic breathable part; 24-partition layer; 25-sealing layer; 3-rod reinforcement; 4-foundation; 5-sand filling layer; 6-guide. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Composite pull-out anchor (also known as combined pull-out anchor) is an anchor with a concrete pile body, a waterproof casing and reinforcement. The reinforcement is arranged in the middle of the concrete pile body, the waterproof casing is arranged inside the concrete pile body and is sleeved on the outside of the reinforcement. The reinforcement is used to bear the pull-out force. The concrete pile body and the waterproof casing form a double-layer barrier to prevent groundwater from corroding the reinforcement.

[0027] The concrete pile body of the traditional composite pull-out anchor is a prefabricated hollow tube or a cylinder cast into the ground. The waterproof casing and the rod reinforcement are connected to the concrete pile body by post-cast cement slurry, such as a combined enhanced pull-out anchor device disclosed in CN211472481U.

[0028] Compared with the concrete pile body of the traditional composite pull-out anchor, the screw pile has stronger pull-out resistance. However, under the action of the pull-out force, the pile body of the traditional screw pile is prone to cracking, and the corrosive medium entering the cracks of the pile body is easy to corrode the stressed steel bars, resulting in reduced safety of the component and weak corrosion resistance. The pull-out pile increases the amount of reinforcement to control the crack width, and the strength of the steel bars cannot be fully utilized. The steel bar content of the single cubic meter concrete is high, and the number of main steel bars is large. Each main steel bar needs to be waterproofed, which makes the construction difficult and the construction period long.

[0029] Since screw piles cannot be prefabricated, the existing construction method of composite pull-out anchors cannot be applied to screw piles. Therefore, people need a composite anchor pull-out screw pile that has the advantages of both screw piles and composite pull-out anchors.

[0030] (First embodiment)

[0031] The following provides a composite anchor anti-pullout screw pile and a construction method thereof, combined with Figure 1 and Figure 2 The construction steps of the composite anchor anti-pullout screw pile include: prefabricating a waterproof casing 2 and a rod reinforcement 3, sealing the bottom of the waterproof casing 2, casting the screw pile 1 underground, and then using a vibrator to insert the waterproof casing 2 into the interior of the screw pile 1 before the screw pile 1 solidifies, ensuring that the top of the waterproof casing 2 is higher than the screw pile 1, then filling the waterproof casing 2 with cement slurry, and then inserting the rod reinforcement 3 into the waterproof casing 2, waiting for the screw pile 1 and the cement slurry to solidify to form a composite anchor anti-pullout screw pile.

[0032] One or more waterproof casings 2 can be inserted into a screw pile 1. When there are a large number of waterproof casings 2, they can be pre-fixed and connected as one, and then inserted into the screw pile 1.

[0033] One or more reinforcement bars 3 can be inserted into each waterproof casing 2. The material of the reinforcement bars 3 can be steel strands or precision-rolled threaded steel bars, both of which have excellent pull-out resistance. Under the double-layer waterproofing effect of the concrete pile body of the screw pile 1 and the waterproof casing 2, the reinforcement bars 3 do not need to be waterproofed.

[0034] The waterproof casing 2 is not only used to isolate the reinforcement 3 and groundwater, but also serves as the skeleton of the screw pile 1. The material of the waterproof casing 2 is corrosion-resistant and tensile-resistant metal or non-metal, such as a low-pressure fluid conveying welded pipe. The waterproof casing 2 also has a certain pull-out resistance and will not crack or leak when the screw pile 1 is subjected to upward pull force.

[0035] Preferably, the bottom end of the waterproof casing 2 is closed by a plug 21 , and the plug 21 is a cone with the tip disposed downward, so that the waterproof casing 2 is more easily inserted into the interior of the screw pile 1 .

[0036] Preferably, at least one guide 6 is welded to the outside of the watertight casing 2. When the number of guides 6 is greater than 1, multiple guides 6 are distributed along the axis of the watertight casing 2. Each guide 6 includes four bends, and the four bends are evenly distributed around the axis of the watertight casing 2. The bends are in the shape of arcs or broken lines. The bends and the axis of the watertight casing 2 are in the same plane. The bends are made of bent steel bars or steel strips. Both ends of the bends are welded to the wall of the watertight casing 2, and the middle end of the bends protrudes outward.

[0037] In addition, after the screw pile 1 is cast, it is necessary to connect the screw pile with the foundation 4 as a whole. The construction steps include: building a mold of the foundation 4 on the ground, tying the rod reinforcement 3 and the steel frame of the foundation 4 as a whole, and then pouring concrete into the mold. After the concrete solidifies, the foundation 4 and the screw pile 1 are connected as a whole through the rod reinforcement 3.

[0038] Preferably, during the construction of the foundation 4, the reinforcement bars 3 may be tensioned and anchored with clip anchors, thereby applying prestress to the composite anchor anti-pullout screw piles.

[0039] Preferably, before constructing the foundation 4 on the ground, the soil can be excavated above the screw pile 1 and backfilled with loose sand material to form a sand filling layer 5, the thickness of the sand filling layer 5 is in the range of 100mm-150mm, so as to reduce the stress concentration at the top of the pile, and the top of the bar 3 passes through the sand filling layer 5 to connect to the steel skeleton of the foundation 4. In summary, combined with Figure 1 , composite anchor anti-pullout screw piles include:

[0040] Screw pile 1, formed underground;

[0041] The waterproof casing 2 is closed at the bottom and vertically inserted into the screw pile 1, and is open at the top and higher than the screw pile 1;

[0042] The reinforcement bar 3 is vertically inserted into the waterproof casing 2 and is tightly combined with the waterproof casing 2 through the filling material filled in the waterproof casing 2.

[0043] The top of the reinforcement bar 3 is higher than the waterproof casing 2, and the filling material is preferably cement slurry.

[0044] The composite anchor anti-pullout screw pile has the advantages of both the screw pile 1 and the composite anti-pullout anchor. The screw pile 1 and the waterproof casing 2 prevent the rod reinforcement 3 from being corroded by groundwater, so that the rod reinforcement 3 can fully exert its anti-pullout performance. The overall anti-pullout performance is better than that of the traditional screw pile 1 and the traditional composite anti-pullout anchor.

[0045] The filling material in the first embodiment can be replaced by other materials that can tightly bond the waterproof casing 2 and the reinforcement 3 after solidification, such as metal glue, epoxy resin, etc.

[0046] (Second embodiment)

[0047] When the diameter of the waterproof casing 2 is large or the number is large, pre-sealing the bottom of the waterproof casing 2 will cause the waterproof casing 2 to encounter greater resistance when inserted into the concrete, especially when the depth is large or the concrete fluidity is low. In order to solve this problem, the bottom of the waterproof casing 2 can be not sealed in advance, and the waterproof casing 2 with an open bottom can be directly inserted into the interior of the screw pile 1. The concrete inside the screw pile 1 can naturally flow into the interior of the waterproof casing 2, reducing the resistance encountered when the waterproof casing 2 is inserted into the concrete. After the bottom of the waterproof casing 2 reaches the predetermined depth, the bottom of the waterproof casing 2 is sealed.

[0048] There are two methods for closing the bottom of the waterproof casing 2 after the bottom of the waterproof casing 2 reaches a predetermined depth.

[0049] Method 1: A closable mechanism, such as a valve and an air bag, is pre-placed at the bottom of the watertight casing 2. After the bottom of the watertight casing 2 reaches a predetermined depth, the valve is closed by pulling the valve through a wire pre-placed inside the watertight casing 2 so that the valve seals the bottom of the watertight casing 2, or the air bag is inflated through a pipe pre-placed inside the watertight casing 2 so that the expanded air bag seals the bottom of the watertight casing 2.

[0050] Method 2: remove the concrete slurry inside the waterproof casing 2 while inserting the waterproof casing 2, or remove the concrete slurry inside the waterproof casing 2 after the bottom of the waterproof casing 2 reaches a predetermined depth, then seal the bottom of the waterproof casing 2, and then backfill with cement slurry.

[0051] The reliability of method one is low because the valve is easily blocked by concrete slurry and is difficult to be completely closed, and the airbag may age or rupture if placed in solidified concrete for a long time. Therefore, method two is preferred.

[0052] Specific, combined Figure 3 , while inserting the waterproof casing 2 into the screw pile 1 with a vibrator, a mud pipe 22 is placed inside the waterproof casing 2. The mud pipe 22 and the waterproof casing 2 are lowered synchronously. After the concrete slurry inside the screw pile 1 enters the waterproof casing 2, it is immediately sucked away by the mud pipe 2. Figure 4 After the bottom of the waterproof casing 2 reaches the predetermined depth, the mud pipe 22 is removed, and the interior of the waterproof casing 2 is empty. Then, epoxy resin is poured into the bottom of the waterproof casing 2. The solidified epoxy resin forms a waterproof sealing layer 25. Then, cement slurry is backfilled into the interior of the waterproof casing 2. Finally, the reinforcement 3 is implanted into the interior of the waterproof casing 2.

[0053] Preferably, the end of the mud pipe 22 is close to and higher than the bottom of the waterproof casing 2, and the end of the mud pipe 22 is pre-wrapped with a cylindrical elastic breathable member 23. The material of the elastic breathable member 23 is sponge, and the outer wall of the elastic breathable member 23 is adhered to the inner wall of the waterproof casing 2.

[0054] During the process of inserting the waterproof casing 2 into the screw pile 1, the elastic air-permeable member 23 is used to prevent the passage of concrete slurry while not hindering the passage of air. After the mud pipe 22 is pulled out of the waterproof casing 2, the through hole located in the center of the elastic air-permeable member 23 for the mud pipe 22 to pass through is closed during the natural expansion of the elastic air-permeable member 23, thereby forming a barrier layer 24 that prevents the concrete slurry from floating up, and at the same time provides a flat bearing surface for the epoxy resin that is subsequently poured into the bottom of the waterproof casing 2. The sealing layer 25 formed after the epoxy resin solidifies directly contacts the inner wall of the waterproof casing 2, preventing the concrete slurry from entering the gap between the epoxy resin and the waterproof casing 2 to form a leakage site.

[0055] A leakage site is formed in the gap between the epoxy resin and the waterproof casing 2.

[0056] The elastic breathable member 23 in the embodiment can be replaced by other materials with elasticity and breathability, such as porous silicone, polyurethane foam, EVA foam, etc. The epoxy resin in the embodiment can be replaced by other materials that have water-proof properties and are not easy to crack after solidification, such as polyurethane resin, polysulfide sealant, water glass, polymer waterproof coating, etc.

[0057] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A construction method for composite anchor anti-pullout screw piles, characterized in that: The following steps are involved: Prefabricated waterproof casing (2) and reinforcement (3); Casting a screw pile (1) underground, inserting the waterproof casing (2) into the interior of the screw pile (1) before the screw pile (1) solidifies, ensuring that the bottom of the waterproof casing (2) is closed and the top of the waterproof casing (2) is higher than the top of the screw pile (1); Filling material is poured into the interior of the waterproof casing (2) with a closed bottom, and then the rod (3) is inserted into the interior of the waterproof casing (2), ensuring that the top of the rod (3) is higher than the top of the waterproof casing (2); Wait for the screw pile (1) and the filling material to solidify.

2. The construction method of a composite anchor anti-pullout screw pile according to claim 1, characterized in that: The filling material is cement slurry.

3. The construction method of a composite anchor anti-pullout screw pile according to claim 2, characterized in that: Before inserting the waterproof casing (2) into the screw pile (1), the bottom of the waterproof casing (2) is sealed in advance.

4. The construction method of a composite anchor anti-pullout screw pile according to claim 1, characterized in that: After the waterproof casing (2) is inserted into the screw pile (1), the bottom of the waterproof casing (2) is sealed.

5. The construction method of a composite anchor anti-pullout screw pile according to claim 4, characterized in that: Before closing the bottom of the waterproof casing (2), the concrete slurry that has flowed from the screw pile (1) into the interior of the waterproof casing (2) is removed to expose the bottom of the waterproof casing (2).

6. The construction method of a composite anchor anti-pullout screw pile according to claim 5, characterized in that: After the bottom of the waterproof casing (2) is exposed, a sealing material is filled in the bottom of the waterproof casing (2) to form a sealing layer (25) that seals the bottom of the waterproof casing (2).

7. The construction method of a composite anchor anti-pullout screw pile according to claim 6, characterized in that: Before inserting the waterproof casing (2) into the screw pile (1), an elastic air-permeable member (23) is bonded inside the waterproof casing (2) and a mud pipe (22) is inserted at the same time, wherein the center of the elastic air-permeable member (23) is provided with a through hole through which the mud pipe (22) can pass; While inserting the waterproof casing (2) into the screw pile (1), the concrete slurry flowing into the waterproof casing (2) is sucked out by the mud pipe (22) to prevent the concrete slurry from floating above the elastic air-permeable member (23); After the bottom of the waterproof casing (2) reaches a predetermined depth, the mud pipe (22) is pulled out, and the elastic air-permeable member (23) naturally expands inward to close the through hole, thereby forming a barrier layer (24) that blocks the concrete slurry from floating up, and the sealing layer (25) is formed above the barrier layer (24).

8. The construction method of a composite anchor anti-pullout screw pile according to claim 1, characterized in that: At least one guide (6) is welded to the outer side of the watertight casing (2). When the number of the guides (6) is greater than 1, a plurality of the guides (6) are distributed along the axis of the watertight casing (2). Each of the guides (6) includes a plurality of bending ribs. The plurality of bending ribs are evenly distributed around the axis of the watertight casing (2). The bending ribs are in the shape of arcs or broken lines. The bending ribs are in the same plane as the axis of the watertight casing (2). The bending ribs are made by bending steel bars or steel strips. Both ends of the bending ribs are welded to the wall of the watertight casing (2), and the middle end of the bending ribs protrudes outward.

9. A construction method for composite anchor anti-pullout screw piles according to any one of claims 1 to 8, characterized in that: After the screw piles (1) are cast underground, a foundation (4) is constructed on the ground.

10. The construction method of composite anchor anti-pullout screw pile according to claim 9, characterized in that: Before constructing the foundation (4) on the ground, a sand filling layer (5) is formed above the screw pile (1) so that the sand filling layer (5) covers the top of the screw pile (1), and after the foundation (4) is formed, the sand filling layer (5) is located between the screw pile (1) and the foundation (4).

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