CN114673204A - A kind of prestressed pressure type anti-floating anchor rod and its construction method - Google Patents

Abstract

The invention provides a prestressed pressure type anti-floating anchor rod and a construction method thereof, which are used in the technical field of building foundations, including a threaded rod body, a nut, a first steel backing plate, an elastic device, a second steel backing plate, an anti-corrosion corrugation Sleeve, locator, thread carrier. The use of anchors to apply and lock the prestress changes the force transmission method, construction method and time of applying the prestress of the prestressed anchor, which improves the construction efficiency, and the prestressed anchors are produced and processed in the factory in advance, and are operated when used at the construction site. It is relatively simple, and the torque wrench can be used to directly screw the nut when applying prestress, which requires less on-site construction equipment, reduces the difficulty of construction technology, and is easy to popularize.

Description

A kind of prestressed pressure type anti-floating anchor and its construction method

technical field

The invention relates to a prestressed pressure type anti-floating anchor rod and a construction method thereof, belonging to the technical field of building foundation foundations.

Background technique

When the counterweight methods such as the self-weight of the structure and the building cover cannot meet the water buoyancy of the basement subjected to groundwater, other measures against water buoyancy shall be taken to ensure the stability of the basement. The existing foundation anti-floating technical measures include anti-floating pile anti-floating and anti-floating anchor rod anti-floating. Anti-floating anchors are mostly used in bedrock foundations, which have high bearing capacity. Generally, shallow foundations can be used to meet the requirements of foundation bearing capacity. When the structure does not meet the anti-floating requirements, anti-floating measures should be taken. It is difficult to use a pile driver to form a hole in the bedrock, and there are special requirements for the pile driver. It is necessary to use a pile driver such as a rotary pile driver to form the hole, which has certain limitations, and the use of uplift piles and anti-floating costs is high. , The construction period is long, and piles are generally not used in bedrock to resist floating.

When the anti-floating anchor is subjected to water buoyancy, the top anchor is prone to cracks under tension, so that the value of the anti-floating anchor's pullout bearing capacity is controlled by the cracks. When the anti-floating design grade is Class A, no tensile stress is allowed. The use of tension type or ordinary bolts cannot meet the specification requirements. The existing prestressed bolt technology is to apply prestress after pouring the basement floor, but there are the following problems:

①Pour the concrete of the basement structure floor first, and then apply the prestressing force. If prestressing is applied after the basement floor concrete is poured, the anchors and rods will protrude on the finished surface of the basement floor, which is unsightly and affects the use of the building. If the building surface layer is used to cover the raised anchors and rods, the clear height of the basement will be reduced, and even the clear height requirements will not be met. At the same time, the prestressing of the prestressed anchor rod requires post-tensioning, and the bottom plate needs to be set with a long sleeve to avoid the contact between the bottom concrete and the rod body for anchoring, and to meet the setting of the free section. The surface of the casing is smooth, and cracks are easily formed on the contact surface when the concrete shrinks. Under the action of water pressure, the groundwater is easy to penetrate upward through the joint surface. There are certain problems in the waterproofing of the bottom plate, and there are hidden dangers in the later stage.

②Pour concrete of the basement structure floor of a certain thickness first, and seal the concrete after the prestressed anchor bolts are tensioned and locked. When pouring the basement floor, reserve a pit on the floor in advance according to the raised height of the anchorage, and fill in the pit after tensioning and locking the anchorage. However, there are many pits to be filled in this method, and the secondary pouring of concrete in a small area is not conducive to vibrating. In addition, the double-layer reinforcement of the bottom plate of the basement structure is set in two directions. In this way, the top reinforcement of the bottom plate affects the tensioning and locking of the anchor rod, and even there is no room for operation. When the thickness of the bottom plate is thin, there is a problem of insufficient anchorage length of the prestressed tendons in the reserved pits.

③ The anchor rod is directly tensioned on the basement layer of the basement structure after pouring, and then the basement basement concrete is poured. Usually the strength level of the cushion concrete is low, and the thickness is only 100mm. The use of jacks to directly tension the tendons is easy to cause damage to the cushion, which is not conducive to the locking of the tendons, and the locking tension is easy to lose, and the effect of prestressing cannot be achieved. , and the prestressed anti-floating anchor is difficult to maintain after stress relaxation due to creep, disturbance and other reasons.

Using the above-mentioned three prestressed anti-floating bolt technologies, there are many construction procedures, long construction period, and there are a series of problems in the use and the safety of the bottom plate.

SUMMARY OF THE INVENTION

The invention provides a prestressed pressure type anti-floating anchor and a construction method thereof. The anchor is used to apply and lock the prestress, which changes the force transmission mode of the prestressed anchor, the construction method and the time for applying the prestress, and improves the performance of the prestressed anchor. construction efficiency. It can effectively reduce the construction cost and shorten the construction period, so that the building can meet the anti-floating requirements.

The technical scheme adopted in the present invention is:

A prestressed pressure type anti-floating anchor rod, comprising a threaded rod body 1, a nut 2, a first steel backing plate 3, an elastic device 4, a second steel backing plate 5, an anti-corrosion corrugated sleeve 6, a locator 7, and a threaded bearing body 8; The threaded rod body (1) passes through the nut 2, the first steel backing plate 3, the elastic device 4, the second steel backing plate 5, the anti-corrosion corrugated sleeve 6, a plurality of positioners 7, and the threaded bearing body respectively from top to bottom. 8. The threaded bearing body 8 is connected to the bottom of the threaded rod body 1, and a plurality of positioners 7 are connected to the middle of the threaded rod body (1), and are arranged at a distance of 1.5m to ensure the verticality of the threaded rod body 1. The concrete cushion layer 18 extends into the basement floor for 100mm, and the lower end extends into the drilled hole for 1-2m;

Preferably, the elastic device 4 is a high-strength spring 9 or a high-strength and high-ductility steel plate 10 , and the high-strength and high-ductility steel plate 10 is 3 pieces in total.

Preferably, there are holes in the middle of the first steel backing plate 3 and the second steel backing plate 5 for the threaded rod body 1 to pass through.

Preferably, the covered part from the first steel backing plate 3 to the anti-corrosion corrugated sleeve 6 and the drilled concrete form the anchor body 11 in the free section of the anchor rod, and the part below the anti-corrosion corrugated sleeve 6 of the threaded rod body 1 is mixed with the drilled concrete The anchoring body 12 of the bonding section is formed; the nut 2, the first steel backing plate 3, the elastic device 4, and the second steel backing plate 5 form a prestressed anchor 13; the anti-corrosion corrugated sleeve 6 is filled with anti-corrosion grease.

Preferably, each of the high-strength and high-ductility steel plates 10 is a rectangle, and is inserted into the limiting grooves provided at the bottom of the first steel backing plate 3 and the top of the second steel backing plate 5, respectively, and the three high-strength and high-ductility steel plates 10 are equilateral triangles. Distribution, the center distance of the first steel backing plate 3 and the second steel backing plate 5 is equal to the midpoint of the short sides of each high-strength and high-ductility steel plate 10, and the midpoints of the short sides of the three high-strength and high-ductility steel plates 10 are connected to form a Equilateral triangle.

Based on the above purpose, the application also proposes a construction method of a prestressed pressure type anti-floating anchor:

①With the top of the drilled hole (16) as the center, set the reinforced mesh (15) within the range of 600mm×600mm, and pour concrete into it to form a concrete cushion (18) with a thickness of 150mm. (5) Puncture, and around the drilled hole, lay a layer of cement-based permeable crystalline waterproof coating on the surface of the concrete cushion (18), and the waterproof coating area is larger than the bottom surface of the second steel cushion (5);

②The prestressed pressure type anti-floating anchor is inserted into the borehole (16), and the cement mortar (14) is poured into the borehole (16) from the grouting pipe (19), and when the cement mortar (14) is solidified, use a wrench Twist the nut (2) to make the elastic device (4) generate prestress, water the basement structure bottom plate (17), and the entire basement structure bottom plate (17) submerges the top of the prestressed pressure type anti-floating anchor rod, and the installation is completed process.

Its working principle is: the construction personnel insert the part below the second steel backing plate 5 into the borehole 16, pour into the concrete slurry, and fill the anti-corrosion corrugated casing 6 with anti-corrosion grease; install the elastic device 4, the construction personnel pass through. The prestress is applied by twisting the nut 2, and after the elastic device 4 is under pressure, a reverse force is generated to realize the application of the prestress. When the building is subjected to water buoyancy, the anchoring body 12 of the bonding section is pulled and squeezes the anchoring body 11 of the free section upward, so that the anchoring body of the free section is in a state of compression, and the bolt transmits the floating tension to the surrounding rock formations through the anchoring body.

The beneficial effects of the invention:

1. Set the free section so that the anchor of the entire free section is in a state of compression. When the anchor rod is subjected to water buoyancy, it can play its own role in time with small deformation. At the same time, a certain pre-compression stress is generated on the anchor in advance, and the compressive stress can be pre-balanced when it is subjected to the pull-up force, and the cracking of the anchor can be effectively avoided under the same pull-out bearing capacity.

2. The use of pre-stressed anchors to apply and lock pre-stress changes the construction process of pre-stressed anchors, the way of force transmission and the time for applying pre-stress, which improves the construction efficiency. It can effectively reduce the construction cost and shorten the construction period.

3. The prestressed anchors are produced and processed in the factory in advance, and the operation is relatively simple when used at the construction site. When applying the prestress, the torque wrench can be used to directly screw the nut, which has low requirements for on-site construction equipment and reduces the difficulty of construction technology.

4. The anchor rod construction is generally completed after the concrete cushion layer is completed, and the finished anchor tool can be used to apply and lock the prestress before pouring the concrete of the basement structure floor. Its stability is good, the locking tension is not easy to lose, and when the steel bars on the basement floor are tied, they will not be deformed due to collision. After the basement floor concrete is poured, it can be effectively anchored to the concrete.

5. The nut, the first steel backing plate, the elastic device and the second steel backing plate of the prestressed anchor can be industrially produced, which can effectively save the construction period. And the structure is simple and easy to produce, the implementation is simple and the applicability is strong, and it is a new channel for the development of the construction engineering industry.

Description of drawings

In order to more clearly illustrate the embodiments of a prestressed pressure type anti-floating anchor rod and its construction method of the present invention or the technical solutions in the prior art, the accompanying drawings required to be used in the description of the embodiments or the prior art will be described below. For a brief introduction, the accompanying drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to the accompanying drawings without creative efforts.

Fig. 1 is the anti-floating anchor rod schematic diagram 1 of the present invention;

Fig. 2 is the schematic diagram 2 of the anti-floating anchor rod of the present invention;

Figure 3 is a prestressed anchor with the elastic device being a high-strength spring;

Figure 4 shows that the elastic device is a prestressed anchorage of high-strength and high-ductility steel plate;

Figure 5 is a top view of the threaded rod body and the anti-corrosion corrugated casing;

6 is a schematic diagram of the distribution of three high-strength and high-ductility steel plates on the first steel backing plate and the second steel backing plate;

Reference number:

Threaded rod body (1), nut (2), first steel backing plate (3), elastic device (4), second steel backing plate (5), anti-corrosion corrugated casing (6), locator (7), thread Bearing body (8), high-strength spring (9), high-strength and high-ductility steel plate (10), free section anchor (11), bonded section anchor (12), prestressed anchor (13), cement mortar (14) ), reinforced mesh (15), drilling holes (16), basement structure floor (17), concrete cushion (18), grouting pipe (19).

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only one embodiment of the present invention, but not all embodiments. . Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

A prestressed pressure type anti-floating anchor rod, comprising a threaded rod body 1, a nut 2, a first steel backing plate 3, a high-strength spring 4, a second steel backing plate 5, an anti-corrosion corrugated sleeve 6, a locator 7, and a threaded bearing body 8; The threaded rod body 1 passes through the nut 2, the first steel backing plate 3, the high-strength spring 4, the second steel backing plate 5, the reinforced mesh 15, the concrete backing layer 18, the anti-corrosion corrugated casing 6, and more from top to bottom respectively. A locator 7 and a threaded bearing body 8, wherein the threaded bearing body 8 is connected to the bottom of the threaded rod body 1, and a plurality of locators 7 are connected to the threaded rod body 1, and are arranged at a distance of 1.5m to ensure the verticality of the threaded rod body 1 and prevent corrosion. The upper end of the corrugated sleeve 6 extends into the basement structure floor 100mm through the concrete cushion 18 , and the lower end extends into the borehole 16 for 1-2m;

The construction method of the prestressed pressure type anti-floating anchor rod is:

①With the top of the drilled hole 16 as the center, set the reinforced mesh 15 within a range of 600mm×600mm, and pour concrete into it to form a concrete cushion 18 with a thickness of 150mm. Around the hole, a layer of cement-based permeable crystalline waterproof coating is laid on the surface of the concrete cushion layer 18, and the waterproof coating area is larger than the bottom surface of the second steel cushion plate 5;

②The prestressed pressure type anti-floating anchor is inserted into the borehole 16, and the cement mortar 14 is poured into the borehole 16 from the grouting pipe 19. After the cement mortar 14 is solidified, use a wrench to twist the nut 2, so that the elastic device 4 is generated. Prestressing, pouring the basement structure bottom plate 17, the entire basement structure bottom plate 17 submerges the top of the prestressed pressure type anti-floating anchor rod, and the installation process is completed.

When the building is subjected to the pulling force or the buoyancy force, the entire anchor body has an upward movement trend relative to the bedrock, and the friction force between the anchor body and the bedrock is downward. The gripping force is upward, the threaded rod body in the free section anchor body is subjected to upward pressure, the prestressed anti-floating anchor rod connecting the entire free section anchor body is subjected to upward pulling force or buoyancy, and the elastic device is downward. prestressed. At this time, the force on the concrete cushion layer 18 is: downward prestress—upward buoyancy—upward gripping force; the downward prestress can be adjusted by nuts, and before the basement structure floor is poured, the prestress has been It is determined that the magnitude of this force must be greater than the sum of the pulling force or buoyancy force and the upward grip force that the building may experience.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (6)

1. The utility model provides an anti-floating anchor of prestressing force pressure type which characterized in that: comprises a threaded rod body (1), a nut (2), a first steel base plate (3), an elastic device (4), a second steel base plate (5), an anti-corrosion corrugated sleeve (6), a positioner (7) and a threaded bearing body (8);

the threaded rod body (1) penetrates through a nut (2), a first steel base plate (3), an elastic device (4), a second steel base plate (5), an anti-corrosion corrugated sleeve (6), a positioner (7) and a threaded supporting body (8) from top to bottom respectively, wherein the threaded supporting body (8) is connected to the bottom of the threaded rod body (1), a plurality of positioners (7) are connected to the middle of the threaded rod body (1) and are arranged at intervals of 1.5m, the upper end of the anti-corrosion corrugated sleeve (6) penetrates through a concrete cushion layer (18) and extends into a basement bottom plate (17) by 100mm, and the lower end of the anti-corrosion corrugated sleeve (6) extends into a drill hole (16) by 1-2 m; the elastic device (4) is positioned between the first steel backing plate (3) and the second steel backing plate (5).

2. The prestressed pressure type anti-floating anchor rod according to claim 1, wherein: the elastic device (4) is a high-strength spring (9) or a high-strength high-ductility steel plate (10), and the number of the high-strength high-ductility steel plates (10) is 3.

3. The prestressed pressure type anti-floating anchor rod according to claim 1, wherein: and a hole for the threaded rod body (1) to pass through is formed between the first steel base plate (3) and the second steel base plate (5).

4. The prestressed pressure type anti-floating anchor rod according to claim 1, wherein: the part from the first steel backing plate (3) to the covering part of the anticorrosive corrugated sleeve (6) and the drilled concrete form an anchor rod free section anchoring body (11), and the part below the anticorrosive corrugated sleeve (6) of the threaded rod body (1) and the drilled concrete are mixed to form a bonding section anchoring body (12); the nut (2), the first steel base plate (3), the elastic device (4) and the second steel base plate (5) form a pre-stressed anchor (13); and the anticorrosive corrugated sleeve (6) is filled with anticorrosive grease.

5. The prestressed pressure type anti-floating anchor rod according to claim 2, wherein each high-strength and high-ductility steel plate (10) is rectangular and is inserted into a limiting groove formed in the bottom of the first steel backing plate (3) and the top of the second steel backing plate (5), the 3 high-strength and high-ductility steel plates (10) are distributed in a regular triangle, the distance between the centers of the first steel backing plate (3) and the second steel backing plate (5) and the middle point of the short side of each high-strength and high-ductility steel plate (10) is equal, and the middle points of the short sides of the 3 high-strength and high-ductility steel plates (10) are connected to form a regular triangle.

6. The prestressed pressure type anti-floating anchor rod according to any one of claims 1 to 5, constructed in a manner that:

setting a steel bar mesh (15) within the range of 600mm multiplied by 600mm by taking the top of a drill hole (16) as a center, pouring concrete into the steel bar mesh to form a concrete cushion (18) with the thickness of 150mm, paving a layer of cement-based permeable crystalline waterproof coating on the surface of the concrete cushion (18) around the drill hole (16), wherein the area of the waterproof coating is larger than that of the bottom surface of a second steel cushion (5);

secondly, the prestress pressure type anti-floating anchor rod is inserted into a drill hole (16), cement mortar (14) is poured into the drill hole (16) from a grouting pipe (19), a wrench is used for twisting the nut (2) after the cement mortar (14) is solidified, so that the elastic device (4) generates prestress to pour a basement structure bottom plate (17), the top of the prestress pressure type anti-floating anchor rod is submerged by the whole basement structure bottom plate (17), and the installation process is finished.

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