CN114809118A - High-pulling-resistance pressure type anti-floating anchor rod and construction method thereof - Google Patents

Abstract

A high-pulling-resistance pressure type anti-floating anchor rod comprises a steel sleeve, a prefabricated reinforced concrete cone point arranged at the bottom of the steel sleeve and at least one steel bar arranged in the steel sleeve, wherein an internal thread sleeve is arranged in the cone point, the steel bar is matched with the internal thread sleeve through an external thread arranged at the bottom of the steel bar, so that the steel bar and the cone point are fixed, the steel bar is coated with anti-corrosion grease, a PE corrugated sheath pipe is sleeved outside the steel bar, the length of the steel bar is greater than that of the sheath pipe, and the length of the steel sleeve is greater than that of the steel bar; the part of the top of the steel bar, which extends out of the PE corrugated sheath pipe, is bent and anchored in the building foundation slab; the construction method of the pressure type anti-floating anchor rod comprises five steps of preparation before construction, steel sleeve driving, concrete pouring, vibration pipe drawing and reinforcing steel bar bending and fixing, the anti-drawing force of the anchor rod is effectively improved by steel sleeve soil squeezing and hole forming, and the pressure type anchor rod enables an anchoring body to bear compressive stress, so that the anchoring body does not generate cracks and is good in corrosion resistance.

Description

A kind of high pullout resistance pressure type anti-floating anchor rod and its construction method

technical field

The invention belongs to the technical field of anti-floating anchor rods, and particularly relates to a high-pulling-resistant pressure type anti-floating anchor rod and a construction method thereof.

Background technique

With the continuous development of urban construction, the use of underground space in urban buildings is increasing, and the development depth is increasing, which brings about the problem of anti-floating of underground projects. The so-called anti-buoyancy is to exert a certain amount of downward drag force on the base plate, so as not to cause the accident to float up because the building is subjected to groundwater buoyancy that is greater than the building's own weight. In order to meet the anti-floating requirements of buildings, measures such as lowering the groundwater level, bottom plate weight, adding vertical uplift piles and anti-floating anchors are often used. The top of the anti-floating anchor is anchored in the base plate of the building foundation, and the lower end goes deep into the soil layer, and the base plate of the building foundation is restrained by the bonding force between the bolt body and the anchor body and the frictional resistance between the anchor body and the soil layer. Floatation due to groundwater buoyancy. The commonly used anti-floating anchors belong to the tension type anchors. The external force is first transmitted to the mortar anchor through the gripping force between the anchor body and the surrounding cement mortar, and then transmitted to the surrounding soil through the anchor. The force is generally controlled by the shear strength between the anchor and the soil. This kind of anchor has the advantages of simple construction and low cost, but sometimes it has the disadvantages of low pullout resistance, easy collapse during construction, and difficulty in ensuring the quality of the anchoring section. Cracks occur, and the corrosion resistance is poor, which affects the service life of the bolt.

SUMMARY OF THE INVENTION

In order to overcome the existing deficiencies, the purpose of the present invention is to provide a high-pull-out-pressure-type anti-floating anchor rod with good anti-corrosion performance and long service life in the anchor body after the anchor rod is stressed, and the same. Anchor construction method.

The purpose of the present invention is to adopt the following technical solutions to achieve. According to the present invention, a high-pulling-resisting pressure-type anti-floating anchor rod comprises a steel casing, a prefabricated reinforced concrete cone tip arranged at the bottom of the steel casing, and at least one reinforcing bar arranged in the steel casing. An inner threaded sleeve is provided, the inner threaded sleeve is fixed with the cone tip and the number is the same as the number of steel bars, the bottom of the steel bar is provided with external threads, the steel bar and the inner threaded sleeve are tightened to fix the steel bar and the cone tip. It is coated with anti-corrosion grease and is also covered with PE corrugated sheathing tube. The length of the steel bar is greater than that of the sheathing tube, and the length of the steel tube is greater than that of the steel bar; The part of the top of the steel bar protruding from the PE corrugated sheath is bent and anchored in the base plate of the building foundation.

Further, the cone tip is a prefabricated reinforced concrete structure, which specifically includes a steel frame and concrete, and the internal thread sleeve and the steel frame are connected by welding and embedded in the concrete.

Further, the inner threaded sleeve is arranged vertically and its bottom is a sealing structure.

Further, the top of the cone tip is provided with steps along the circumferential direction, and the bottom of the steel sleeve is in contact with the steps.

Further, the top of the steel bar is bent and anchored in the base plate of the building foundation.

Further, the construction method of the high pullout resistance pressure type anti-floating anchor comprises the following steps:

(1) Prepare for construction

Apply anti-corrosion grease to the anchoring section of the steel bar and set a PE corrugated sheath on the outside to connect and fix the steel bar and the cone tip; mark the design elevation on the steel sleeve and install the cone tip on the lower end of the steel sleeve.

(2) Setting of steel casing

The hole is formed by the immersed tube method, and the steel casing is vertically driven or pressed into the soil to the design elevation by hammering or vibration.

(3) pouring concrete

Anchor concrete is poured into the steel casing.

(4) Vibration extubation

Vibrate first, then pull out the pipe and add concrete in sections to the base plate level of the building foundation, and then pull out the steel casing completely.

(5) Bending and fixing of steel bars

After the construction of the anchor rod is completed, the top of the steel bar is bent and anchored in the base plate of the building.

By means of the above technical solutions, the advantages of the present invention are: during the construction of the pressure-type bolt of the present invention, the steel casing is squeezed into the soil to form holes, which enhances the frictional resistance between the soil and the anchor, and effectively improves the pull-out resistance of the bolt. ; The bottom of the steel casing is provided with a cone tip, which can improve the efficiency of driving or pressing the steel casing into the soil; the outside of the anchoring section is coated with anti-corrosion grease and has a corrugated sheath to avoid direct contact between the steel and the anchoring concrete. The bottom of the steel bar is fixed with the taper tip through the thread. After pouring concrete into the steel casing, the tensile force on the anchor rod is directly transferred from the steel bar to the taper tip at the bottom, and then transferred to the entire anchor body, and then passes through the connection between the anchor body and the surrounding soil. The friction force provides the anchoring force, and the anchor body is subjected to compressive stress, so that the anchor body does not crack, the bolt has high corrosion resistance, long service life, and high quality of the anchoring section.

The above description is only an overview of the technical solution of the present invention, in order to understand the technical means of the present invention more clearly, it can be implemented according to the content of the description, and in order to make the above and other objects, features and advantages of the present invention more obvious and easy to understand , the following specific preferred embodiments, and in conjunction with the accompanying drawings, are described in detail as follows.

Description of drawings

Fig. 1 is the structural representation of a kind of high pull-out resistance pressure type anti-floating anchor rod of the present invention;

Fig. 2 is the structural representation of the cone tip in Fig. 1;

Fig. 3 is the top view of Fig. 2;

Fig. 4 is the structural representation of the steel skeleton of the tapered tip in the present invention;

Fig. 5 is a schematic diagram of the construction state of a high pull-out force pressure type anti-floating anchor rod according to the present invention.

[reference number]

1-Steel casing, 2-Rebar, 3-PE corrugated sheath, 4-Conical tip, 401-Rebar frame, 402-Concrete, 5-Internal thread casing, 6-Step, 7-Building foundation plate, 8 - Anchor.

Detailed ways

In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following describes a high-pulling-resistant pressure type anti-floating anchor rod and its construction according to the present invention in conjunction with the accompanying drawings and preferred embodiments. The specific implementation, structure, features and efficacy of the method are described in detail as follows.

Please refer to FIGS. 1 to 4 , a high-pulling-resistance pressure-type anti-floating anchor includes a steel sleeve 1 and a cone tip 4 arranged at the bottom of the steel sleeve 1 , and the cone tip 4 is a reinforced concrete structure, including a steel frame 401 and concrete 402, at least one inner threaded sleeve 5 is provided in the cone tip 4, the inner threaded sleeve 5 and the steel frame 401 are fixed by welding and embedded in the concrete 402, the inner threaded sleeve 5 is vertically arranged and its top It is flush with the top of the cone tip, and the bottom is a sealing structure; the top of the cone tip 4 is provided with a step 6 along the circumferential direction, and the bottom of the steel sleeve 1 is in contact with the step 6. During construction, the steel sleeve 1 is hammered or vibrated. Vertically driving or pressing into the soil to the elevation, during the process of hammering or vibrating the steel casing 1, the force is transmitted to the cone tip 4 through the steel casing 1. Due to the conical setting of the cone tip 4, the steel casing 1 can be improved. The efficiency of driving or pressing into the soil.

At least one reinforcing bar 2 is arranged inside the steel sleeve 1 , the number of the reinforcing bars 2 corresponds to the number of the internally threaded sleeves 5 and the length of the reinforcing bar 2 is smaller than the length of the steel sleeve 1 . The section outside the steel bar 2 that can form the final anchor is the anchoring section of the steel bar 2. The anchoring section of the steel bar 2 is coated with anti-corrosion grease, and a PE corrugated sheath tube 3 is also set outside the anchor section. The diameter of the PE corrugated sheath tube 3 is slightly larger than that of the steel bar. 2 diameter, the PE corrugated sheath tube 3 is set on the steel bar to isolate the steel bar 2 from the concrete, which can prevent the force generated by the anchoring section from directly acting on the steel bar 2. In addition, the length of the steel bar 2 is greater than the length of the PE corrugated sheath tube 3, the top and bottom of the steel bar 2 protrude from the PE corrugated sheath tube 3, and the part of the top of the steel bar 2 that extends out of the PE corrugated sheath tube 3 is bent away from the center of the anchor hole Bending and anchoring at 90 degrees in the base plate 7 of the building to prevent the base plate 7 of the building from floating up, further ensuring the quality of the anti-floating anchor; The external thread provided in the threaded section cooperates with the internal thread in the threaded sleeve 5 , and the reinforcing bar 2 is threadedly matched with the internal threaded sleeve 5 through the external thread section to fix the reinforcing bar 2 and the cone tip 4 together.

After the construction of the anchor rod is completed, when the building is lifted up by the groundwater, the anchor rod is subjected to upward pulling force, and the pulling force is directly transmitted by the steel bar 2 to the cone tip 4 at the bottom, and the compressive stress is applied to the bottom of the anchor body through the cone tip 4 and then transmitted to the whole. In the anchor body 8, the anchoring force is provided by the friction force between the anchor body 8 and the surrounding soil. The anchoring body is always under pressure without cracks, thereby improving the corrosion resistance of the anchor rod, prolonging the service life, and ensuring the quality of the anchoring section; the shear stress between the anchoring body and the surrounding soil is transmitted forward from the bottom of the anchor hole, and the shear stress The distribution is more uniform than that of tensile anchors and the shear strain is smaller under the same load.

With reference to Figure 5, the present invention also provides a construction method for the above-mentioned high pull-out force pressure type anti-floating anchor, comprising the following steps:

(1) Preparation before construction

a) Coat the anchor section of the steel bar 2 with anti-corrosion grease and set the PE corrugated sheath tube 3 on the outside thereof; b) The external thread section of the steel bar 2 and the inner threaded sleeve 5 on the cone tip 4 are screwed together. 2 is fixed on the cone tip 4; c) mark the design elevation on the steel casing 1 and set the steel casing 1 outside the rebar 2, the cone tip 4 is installed at the bottom of the steel casing 1, and the bottom of the steel casing 1 is placed at the bottom of the steel casing 1. On step 6; d) Design and construction position.

(2) Setting of steel casing

The steel casing 1 is drilled by the immersed tube method, and the top of the steel casing 1 is drilled by hammering or vibration. The steel casing 1 is vertically driven or pressed into the soil at the design position to the design elevation. 2. The top part of the PE corrugated sheath tube 3 extends into the building foundation plate.

The immersed tube method can avoid the formation of collapsed holes during construction, and at the same time, the soil layer around the anchor body is squeezed laterally, which increases the compactness of the soil body, improves the lateral resistance of the soil body to the anchor body, and finally improves the anchor rod. The immersed tube method can form a larger anchor hole, and the diameter of the concrete anchor is larger, which can provide a larger pull-out force on the one hand, and on the other hand, when the required anchor rod pull-out force is constant, it can be reduced. Small bolt length, thus saving material.

(3) pouring concrete

Anchor concrete is poured into the steel casing 1 .

(4) Vibration extubation

After the concrete in the steel casing 1 is poured to a certain height, vibrate first, then pull out the pipe, add concrete in sections to the base plate 7 of the building, and then pull out the steel casing 1 completely.

(5) Bending and fixing of steel bars

After the anchor construction is completed, the steel bars 2 in the building foundation bottom plate 7 are bent 90 degrees away from the center of the anchor bolts, and the steel bars are anchored in the building foundation bottom plate 7 to prevent the building foundation bottom plate 7 from floating, and further ensure the anti-floating anchor. quality of the rod.

The above are only the preferred embodiments of the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make any simple modifications to the above embodiments according to the technical essence of the present invention, Equivalent changes and modifications still fall within the scope of the technical solutions of the present invention.

Claims (6)

1. a high pull-out force pressure type anti-floating anchor is characterized in that: comprising a steel casing, a prefabricated reinforced concrete cone tip arranged at the bottom of the steel casing and at least one reinforcing bar arranged in the steel casing, the cone tip. There is an inner threaded sleeve inside, the inner threaded sleeve is fixed with the cone tip and the number is the same as the number of steel bars, the bottom of the steel bar is provided with an external thread, the steel bar and the inner threaded sleeve are tightened to fix the steel bar and the cone tip, and the steel bar is screwed together. It is coated with anti-corrosion grease and is also covered with PE corrugated sheathing tube. The length of the steel bar is greater than the length of the sheathing tube, and the length of the steel tube is greater than that of the steel bar; the top and bottom of the steel bar are protruding from the PE corrugated sheathing tube. And the part of the top of the steel bar protruding from the PE corrugated sheath is bent and anchored in the base plate of the building foundation. 2. a kind of high anti-pulling force pressure type anti-floating anchor rod according to claim 1 is characterized in that: the cone tip is a prefabricated reinforced concrete structure, and specifically comprises a steel skeleton and concrete, and the inner threaded casing and the steel skeleton are welded by welding connected and embedded in concrete. 3 . The high-pulling-resistant pressure-type anti-floating anchor rod according to claim 1 , wherein the inner threaded sleeve is arranged vertically and the bottom thereof is a sealing structure. 4 . 4 . The high-pullout-resistance pressure-type anti-floating anchor rod according to claim 1 , wherein the top of the cone tip is provided with steps along the circumferential direction, and the bottom of the steel casing is in contact with the steps. 5 . 5 . The high-pullout-resistance pressure-type anti-floating anchor rod according to claim 1 , wherein the top of the steel bar is bent and anchored in the base plate of the building. 6 . 6. The high-pullout-resistance pressure-type anti-floating anchor rod according to any one of claims 1-5, wherein the construction method of the high-pull-out-resistance pressure type anti-floating anchor rod comprises the following steps: (1) Prepare for construction Apply anti-corrosion grease to the anchoring section of the steel bar and set a PE corrugated sheath on the outside to connect and fix the steel bar and the cone tip; mark the design elevation on the steel sleeve and install the cone tip on the lower end of the steel sleeve. (2) Setting of steel casing The hole is formed by the immersed tube method, and the steel casing is vertically driven or pressed into the soil to the design elevation by hammering or vibration. (3) pouring concrete Anchor concrete is poured into the steel casing. (4) Vibration extubation Vibrate first, then pull out the pipe and add concrete in sections to the base plate level of the building foundation, and then pull out the steel casing completely. (5) Bending and fixing of steel bars After the construction of the anchor rod is completed, the top of the steel bar is bent and anchored in the base plate of the building.

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