PSB anti-floating anchor rod with active pressure reduction function and construction method thereof

Abstract

The present application belongs to the technical field of anti-floating anchor rod, and discloses a PSB anti-floating anchor rod with active pressure reduction function and a construction method thereof, in order to solve the problem that the anti-floating anchor rod is damaged due to excessive upward force caused by rapid growth of underground water level. A PSB finished rolled threaded steel pipe is inserted into an anchor hole, the PSB finished rolled threaded steel pipe has a cavity, an anchoring body is formed by pouring between the anchor hole and the PSB finished rolled threaded steel pipe, the PSB finished rolled threaded steel pipe sequentially comprises an extension section, a cement mortar section, a connecting section and a flower hole section from top to bottom, a plurality of through holes which are in communication with the cavity inside the PSB finished rolled threaded steel pipe are formed on the flower hole section of the PSB finished rolled threaded steel pipe, the extension section extends out a cushion layer laid on the top of the anchor hole and a basement bottom plate laid above the cushion layer, a valve is arranged on the top of the extension section, a pipeline is further communicated with the top of the extension section, a pore pressure gauge and a water pump are arranged on the pipeline.

Description

Technical Field

[0001] This invention belongs to the field of anti-buoyancy anchor technology, specifically relating to a PSB anti-buoyancy anchor with active pressure reduction function and its construction method. Background Technology

[0002] Anti-buoyancy anchors are a type of anti-buoyancy measure for underground structures. Unlike ordinary foundation piles, anti-buoyancy anchors have unique properties. The biggest difference lies in their resistance to pressure: foundation piles typically withstand compressive stress, with the load pressure transmitted from the top to the bottom of the pile, and the magnitude of the stress changing with the building load; while anti-buoyancy anchors withstand tensile stress. Although the stress in ordinary anti-buoyancy anchors also transmits from the top to the bottom of the pile, and the magnitude of the stress changes with groundwater levels, their stress mechanisms are exactly opposite.

[0003] To enhance the pull-out resistance of anti-buoyancy anchors, the industry currently mostly uses enlarged head anti-buoyancy anchors or high-strength precision rolled threaded steel PSB anti-buoyancy anchors. However, with the frequent occurrence of extreme weather in recent years, traditional anti-buoyancy anchors often cannot withstand the buoyancy of the basement when the groundwater level rises rapidly. In some cases, the anti-buoyancy anchors may even suffer irreparable damage due to excessive buoyancy, thus causing the anti-buoyancy measures of the entire building to fail.

[0004] However, most current research on drainage for anti-buoyancy anchors focuses on how to prevent water from seeping into the anchors, such as by using waterproof coatings, with the aim of preventing groundwater from corroding the anchors.

[0005] To prevent groundwater from affecting anti-buoyancy anchors, patent application number 2022109266289 discloses a pressure-type prestressed anti-buoyancy anchor waterproof structure, including a cylindrical waterproof sleeve and a bottom water-blocking block. The cylindrical waterproof sleeve penetrates from bottom to top through an underground mudstone layer, a hollow waterproof layer, a concrete waterproof protective layer, and a waterproof membrane layer. A pressure-type prestressed anti-buoyancy anchor is installed inside the cylindrical waterproof sleeve, and waterproof polyurethane sealant is filled between the pressure-type prestressed anti-buoyancy anchor and the cylindrical waterproof sleeve. A bottom water-blocking block is installed at the bottom of the cylindrical waterproof sleeve, and the pressure-type prestressed anti-buoyancy anchor passes through the bottom water-blocking block through an anchor positioning groove. A waterproof rubber ring is installed between the pressure-type prestressed anti-buoyancy anchor and the anchor positioning groove. A hollow drainage pipe penetrates inside the bottom water-blocking block, and honeycomb columns and movable water-stop columns are installed inside the hollow drainage pipe. An inclined water guide pipe is connected to one side of the hollow drainage pipe, and the top of the hollow drainage pipe is sealed.

[0006] According to the document, the technology "avoids excessive groundwater levels causing a surge in moisture that could enter the cylindrical waterproof sleeve, allowing for stable drainage of water from the sleeve; it also prevents groundwater from penetrating the hollow waterproof layer and allows surface water to quickly seep down through the support pipes of the hollow waterproof layer." This indicates that the technology only prevents groundwater from seeping around the anchor rod. However, when the groundwater level rises rapidly, the groundwater around the anti-buoyancy anchor rod cannot be drained in time (i.e., the groundwater level in the soil around the anti-buoyancy anchor rod rises, leaving no room for drainage or seepage), resulting in excessive buoyancy and damage to the anti-buoyancy anchor rod. Summary of the Invention

[0007] To address the problem of excessive buoyancy damaging anti-buoyancy anchors due to rapid groundwater level rise, this invention provides a PSB anti-buoyancy anchor with active depressurization function and its construction method. This method can actively depressurize groundwater, quickly remove groundwater, and restore the groundwater level to a controllable range, thus preventing damage to the anti-buoyancy anchors caused by rapidly rising groundwater and the failure of the building's anti-buoyancy measures.

[0008] To solve the technical problem, the technical solution adopted by this invention is as follows:

[0009] A PSB anti-buoyancy anchor bolt with active pressure reduction function includes an anchor hole drilled in the soil. The anchor hole comprises a standard section and an enlarged section from top to bottom. The anchor bolt is characterized by inserting a PSB precision-rolled threaded steel pipe into the anchor hole. The PSB precision-rolled threaded steel pipe has a cavity. An anchor body is cast between the standard section and the enlarged section of the anchor hole and the outer wall of the PSB precision-rolled threaded steel pipe. The PSB precision-rolled threaded steel pipe comprises, from top to bottom, an extension section, a cement mortar section, a connecting section, and a perforated section. The cement mortar section is connected to the anchor... The ordinary section and the enlarged head section of the hole are mutually compatible. The connecting section is located below the enlarged head section of the anchor hole. The perforated section of the PSB precision-rolled threaded steel pipe has several through holes communicating with the internal cavity of the PSB precision-rolled threaded steel pipe. The extension section extends to the pad layer laid on top of the anchor hole and the basement floor slab laid on top of the pad layer. The top of the extension section is equipped with a valve, which is a valve with a pore pressure sensor. The top of the extension section is also connected to a pipe, which is equipped with a pore pressure gauge and a water pump.

[0010] In some embodiments, a filter screen is wrapped around the periphery of the perforated section of the PSB precision-rolled threaded steel pipe.

[0011] In some embodiments, an annular groove is provided around the perforated section of the PSB precision-rolled threaded steel pipe, and the filter screen is installed in the annular groove and can cover the through hole of the PSB precision-rolled threaded steel pipe.

[0012] In some embodiments, the lower end of the PSB precision-rolled threaded steel pipe has a pointed tip.

[0013] In some embodiments, the extension section is provided with anchorages in the area corresponding to the basement floor slab.

[0014] In some embodiments, the cement mortar section of the PSB precision-rolled threaded steel pipe is equipped with a plurality of bearing plates corresponding to the enlarged head section of the anchor hole. The bearing plates are used to increase the interaction force between the pipe and the anchor body.

[0015] This invention also provides a construction method for a PSB anti-buoyancy anchor bolt with active pressure reduction function, characterized in that it includes:

[0016] (1) The site is leveled, and the soil is drilled into the soil to form anchor holes according to the design requirements. The anchor holes include ordinary sections and enlarged head sections.

[0017] (2) The pre-prepared PSB fine-rolled threaded steel pipe is inserted into the anchor hole, and the cement pouring section of the PSB fine-rolled threaded steel pipe corresponds to the ordinary section and the enlarged head section of the anchor hole. The extension section of the PSB fine-rolled threaded steel pipe extends upward out of the soil surface. The connecting section and the perforated section of the PSB fine-rolled threaded steel pipe are inserted into the soil below the enlarged head section of the anchor hole. The perforated section of the PSB fine-rolled threaded steel pipe has a through hole that communicates with the cavity of the PSB fine-rolled threaded steel pipe.

[0018] (3) Cement mortar is poured in the area between the anchor hole and the outer wall of the PSB precision threaded steel pipe to form an anchor body;

[0019] (4) Pouring the foundation layer and basement floor slab;

[0020] (5) A valve with a pore pressure sensor is installed on the top of the PSB fine-rolled threaded steel pipe, and then a water pump is connected through a pipeline, on which a pore pressure gauge is installed.

[0021] (6) The pore pressure sensor sends the detection data to the pore pressure gauge. When the value displayed by the pore pressure gauge is greater than or equal to the set value, the pore pressure gauge controls the valve to open and controls the water pump to work to extract groundwater in the PSB precision rolled threaded steel pipe. When the value displayed by the pore pressure gauge is less than the set value, the pore pressure gauge controls the valve to close and controls the water pump to stop.

[0022] In some embodiments, the inner wall, outer wall, and borehole wall of the PSB precision-rolled threaded steel pipe are all subjected to anti-corrosion treatment.

[0023] In some embodiments, if the area below the enlarged section of the anchor hole is a hard stratum, when drilling with a drilling rig, drilling continues below the enlarged section of the anchor hole to form an insertion section, the depth of which is adapted to the sum of the lengths of the connection section and the perforated section of the PSB precision-rolled threaded steel pipe.

[0024] In some embodiments, a sealing plate is fitted on the top of the connecting section of the PSB precision-rolled threaded steel pipe, and the sealing plate is threadedly connected to the PSB precision-rolled threaded steel pipe. The outer dimensions of the sealing plate are larger than the dimensions of the insertion section and are adapted to the dimensions of the ordinary section of the anchor hole.

[0025] In some embodiments, the outer circumferential wall and bottom surface of the sealing plate are provided with a sealing layer made of a flexible material.

[0026] In some embodiments, the connecting section of the PSB precision-rolled threaded steel pipe is covered with a sealing sleeve.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention relates to a PSB anti-buoyancy anchor bolt with active pressure reduction function and its construction method. By designing the PSB threaded steel pipe as hollow (i.e., the PSB threaded steel pipe has cavities arranged along its length), it ensures the PSB threaded steel pipe's anti-buoyancy capability as an anti-buoyancy anchor bolt, thereby ensuring the stability and safety of the structure. When encountering heavy rain or the rainy season, and the groundwater level rises, groundwater enters the cavity of the PSB threaded steel pipe through the perforated section (the through-holes in the perforated section). The water is then pumped out of the PSB threaded steel pipe via water pumps and pipelines, thereby lowering the groundwater level and ensuring it remains within a controllable range (i.e., without damaging the structure of the anti-buoyancy anchor bolt, ensuring the anti-buoyancy anchor bolt can provide sufficient pull-out force for the structure). This invention cleverly integrates the anti-buoyancy anchor plate and groundwater drainage into one unit, ensuring the normal use of the anti-buoyancy anchor bolt while preventing its failure due to rising groundwater levels.

[0029] Compared to existing technologies, the structure of this invention is simple and ingenious. Compared to existing technologies that rely on groundwater seepage around the anti-buoyancy anchor to prevent damage, this invention completely solves the problem of groundwater levels affecting the structural safety of the anti-buoyancy anchor. It can actively reduce groundwater levels, ensuring that the groundwater level remains within a controllable design range and that the anti-buoyancy anchor's function is not affected by severe weather such as rainy seasons or heavy rain.

[0030] Simultaneously, the anti-buoyancy anchor of this invention can also be used for dewatering foundation pits. During foundation pit excavation, although dewatering wells are arranged around the pit to lower the groundwater level and ensure dryness, these wells are typically located around the perimeter of the pit and at a certain distance. After excavation, if rainy season or heavy rain occurs, the groundwater level at the bottom of the pit will rise. Due to the soil structure, it takes time for the groundwater to seep into the dewatering wells. However, after the anti-buoyancy anchor is installed, this invention can directly use PSB precision-rolled threaded steel pipes to drain the groundwater, achieving rapid groundwater removal and shortening the dewatering time. This facilitates the construction of the foundation layer and basement slab, thereby reducing the construction period. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a structure of an embodiment of the PSB anti-buoyancy anchor bolt with active pressure reduction function of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of the present invention when anchor holes are opened on the soil surface;

[0033] Figure 3 This is a schematic diagram of the structure of the present invention when a PSB precision-rolled threaded steel pipe is implanted in the anchor hole, wherein... Figure 3 In this context, a, b, c, and d represent the perforated section, connecting section, cement mortar section, and extension section of the PSB precision-rolled threaded steel pipe, respectively.

[0034] Figure 4 A schematic diagram of the structure when cement mortar is poured between the anchor hole and the PSB precision-rolled threaded steel pipe to form an anchor body;

[0035] Figure 5 This is a structural diagram showing the pouring of the cushion layer and basement floor slab at the top of the anchor hole;

[0036] Figure 6 This is a schematic diagram of another embodiment of the connecting section and perforated section of the PSB precision-rolled threaded steel pipe of the present invention;

[0037] Marked in the diagram: 1. Soil surface, 2. Ordinary section, 3. Enlarged head section, 4. PSB precision-rolled threaded steel pipe, 41. Cavity, 42. Through hole, 43. Filter screen, 44. Bearing plate, 46. Sealing layer, 47. Sealing sleeve, 5. Valve, 6. Anchor body, 7. Subbase, 8. Basement floor slab, 9. Anchor, 10. Pipe, 11. Sump, 12. Pore pressure gauge. Detailed Implementation

[0038] The present invention will be further described below with reference to embodiments. These embodiments are merely some, not all, of the embodiments of the present invention. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the protection scope of the present invention.

[0039] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] Combined with appendix Figure 1 To be continued Figure 6The PSB anti-buoyancy anchor bolt with active pressure reduction function of the present invention includes an anchor hole opened in the soil. The anchor hole includes, from top to bottom, a normal section 2 and an enlarged head section 3. The normal section 2 is described relative to the enlarged head section 3. The normal section 2 (also called the straight section) is simply smaller in diameter than the enlarged head section 3. This is clear to those skilled in the art and will not be elaborated further here. A PSB precision-rolled threaded steel pipe is inserted into the anchor hole. The PSB precision-rolled threaded steel pipe has a cavity 41, which is opened along the length direction of the PSB precision-rolled threaded steel pipe 4. In the specific real-time process, cavity 41 is a blind hole opened in the middle of the PSB threaded steel pipe and set along the length of the PSB threaded steel pipe. An anchor body 6 is cast between the ordinary section 2 and the enlarged head section 3 of the anchor hole and the outer wall of the PSB threaded steel pipe 4. The PSB threaded steel pipe 4 includes, from top to bottom, an extension section d, a cement mortar section c, a connecting section b, and a perforated section a. The cement mortar section c is compatible with the ordinary section 2 and the enlarged head section 3 of the anchor hole. The connecting section b is the anchor hole. Below the enlarged head section 3, the perforated section a of the PSB precision-rolled threaded steel pipe 4 has several through holes 42 communicating with the internal cavity 41 of the PSB precision-rolled threaded steel pipe. The extension section extends to the pad layer laid on top of the anchor hole and the basement floor slab laid on top of the pad layer. The top of the extension section d is equipped with a valve 5, which is a valve with a pore pressure sensor. The top of the extension section d is also connected to a pipe 10, which is equipped with a pore pressure gauge 12 and a water pump. In the actual process, the pipe is also connected to a water collection tank 11. The groundwater in each PSB precision-rolled threaded steel pipe is pumped into the water collection tank 11 for centralized treatment, such as for later construction water, garden sprinkler, etc.

[0041] Pore ​​pressure sensors, also known as pore water pressure sensors, pore pressure gauges, osmotic pressure gauges, etc., are sensors used to measure the pore water pressure or osmotic pressure inside structures. They are suitable for measuring water pressure and level in pipes, backfill or in-situ pore water pressure, and fluid pressure in water levels or containers. They feature strong anti-interference capabilities, long-term stability, and reliable sealing. The specific characteristics of pore pressure sensors are readily understood by those skilled in the art and will not be elaborated upon further here.

[0042] In some embodiments, a filter screen 43 is wrapped around the periphery of the perforated section a of the PSB precision-rolled threaded steel pipe 4. The filter screen protects the through hole 42, preventing soil from entering and clogging the through hole 42.

[0043] In some embodiments, an annular groove is formed around the perforated section a of the PSB threaded steel pipe 4. The filter screen 43 is installed in the annular groove and can cover the through hole 42 of the PSB threaded steel pipe. In actual operation, the filter screen 3 is fixed in the annular groove by means of clamps, bolts, etc. The design of the annular groove allows the size of the filter screen fixing area to be smaller than the outer diameter of the PSB threaded steel pipe, thereby providing a certain degree of protection for the filter screen and preventing damage to the filter screen 43 when the PSB threaded steel pipe is inserted.

[0044] In some embodiments, the lower end of the PSB threaded steel pipe 4 has a pointed tip. That is, the lower end of the perforated section has a pointed tip, which facilitates the insertion of the PSB threaded steel pipe into the soil below the enlarged head section. Specifically, when inserting the PSB threaded steel pipe into the anchor hole, a certain downward pressure can be applied to the top of the PSB threaded steel pipe to allow the connecting section and the perforated section of the PSB threaded steel pipe to be inserted into the soil below the enlarged head section 3.

[0045] In some embodiments, the extension section d is provided with an anchor 9 in the area corresponding to the basement floor slab 8. The anchor used for anchoring PSB precision-rolled threaded steel pipes is prior art. The anchor mainly includes an anchor plate and a locking nut. The PSB precision-rolled threaded steel pipes are anchored by applying prestress through the anchor, which is understood by those skilled in the art and will not be described in detail here.

[0046] In some embodiments, the cement mortar section c of the PSB precision-rolled threaded steel pipe 4 is equipped with a plurality of bearing plates 44 corresponding to the enlarged head section 3 of the anchor hole. The bearing plates 44 are used to increase the interaction force between the bearing plate and the anchor body 6.

[0047] This invention also provides a construction method for a PSB anti-buoyancy anchor bolt with active pressure reduction function, comprising:

[0048] (1) Site leveling, i.e., leveling the soil surface 1 to facilitate the placement of equipment (e.g., drilling rig), is self-evident to those skilled in the art and will not be elaborated further. The soil is then drilled using the drilling rig to form anchor holes according to design requirements. These anchor holes include a standard section 2 and an enlarged head section 3. After drilling the anchor holes, the holes should be cleaned to prevent sediment buildup. Simultaneously, the site engineer and quality inspector will check the hole depth and anchor hole deviation. Once the requirements are met, the next construction step can proceed.

[0049] (2) The pre-prepared PSB threaded steel pipe 4 is inserted into the anchor hole, with the cement-cast section c of the PSB threaded steel pipe corresponding to the ordinary section 2 and the enlarged head section 3 of the anchor hole. The extension section of the PSB threaded steel pipe extends upward out of the soil surface 1. The connecting section b and the perforated section a of the PSB threaded steel pipe 4 are both inserted into the soil below the enlarged head section 3 of the anchor hole. The perforated section a of the PSB threaded steel pipe 4 has a through hole 42 that communicates with the cavity 41 of the PSB threaded steel pipe. That is to say, the PSB threaded steel pipe 4 is pre-fabricated according to the design requirements, including the opening of the cavity 41, the opening of the through hole 42, etc.

[0050] (3) Cement mortar is poured in the area between the anchor hole and the outer wall of the PSB precision threaded steel pipe 4 to form the anchor body 6;

[0051] (4) Pouring the foundation layer 7 and the basement floor slab 8; wherein, after the foundation layer 7 is poured, the PSB precision-rolled threaded steel pipe 4 is locked by anchors 9. In some embodiments, prestress is applied to the PSB precision-rolled threaded steel pipe 4 and then the PSB precision-rolled threaded steel pipe 4 is locked by anchors 9. Applying prestress to the PSB precision-rolled threaded steel pipe 4 and locking it by anchors 9 are existing technologies, which can be understood by those skilled in the art and will not be described in detail here.

[0052] (5) A valve 5 with a pore pressure sensor is installed on the top of the PSB fine-rolled threaded steel pipe 4, and then a water pump is connected through a pipe 10, on which a pore pressure gauge 12 is installed.

[0053] (6) The pore pressure sensor sends the detection data to the pore pressure gauge 12. When the value displayed by the pore pressure gauge 12 is greater than or equal to the set value, the pore pressure gauge 12 controls the valve 5 to open and controls the water pump to work to extract groundwater from the PSB precision-rolled threaded steel pipe 4. When the value displayed by the pore pressure gauge 12 is less than the set value, the pore pressure gauge 12 controls the valve 5 to close and controls the water pump to stop. The attached drawings of this application do not show a schematic diagram of the water pump. The water pump and pipeline are used to extract and discharge groundwater from the PSB precision-rolled threaded steel pipe.

[0054] In some embodiments, the inner wall, outer wall, and borehole wall of the PSB precision-rolled threaded steel pipe 4 are all subjected to anti-corrosion treatment. This anti-corrosion treatment includes, but is not limited to, electroplating an anti-corrosion layer and coating an anti-corrosion layer. Anti-corrosion treatment of PSB precision-rolled threaded steel is prior art and is clear and understandable to those skilled in the art, and will not be elaborated upon here.

[0055] In some embodiments, if the area below the enlarged head section 3 of the anchor hole is a hard stratum, when drilling with a drilling rig, drilling continues below the enlarged head section 3 of the anchor hole to form an insertion section. The depth of the insertion section is adapted to the sum of the lengths of the connecting section b and the perforated section a of the PSB precision rolled threaded steel.

[0056] In the actual real-time process, the diameter of the insertion section is slightly smaller than the diameter of the connection section and the perforated section of the PSB precision rolled threaded steel pipe, so that the connection section and the perforated section of the PSB precision rolled threaded steel pipe can achieve an interference fit with the insertion section.

[0057] Since the force between the PSB precision-rolled threaded steel pipe and the soil comes from the force between the anchor body (i.e., the anchor nail formed around the cement mortar section of the PSB precision-rolled threaded steel pipe) and the soil, the opening of the insertion section will not affect the anti-buoyancy force of the entire anti-buoyancy anchor rod.

[0058] In some embodiments, a sealing plate 45 is fitted onto the top of the connecting section b of the PSB precision-rolled threaded steel pipe 4 (that is, the sealing plate 45 is located between the cement mortar section c and the connecting section b, and the sealing plate 45 can be adapted to the bottom surface of the enlarged head section 3 of the anchor rod during operation, thereby achieving stability of the sealing plate 45 by utilizing the stepped surface of the enlarged head section 3). The sealing plate 45 is threadedly connected to the PSB precision-rolled threaded steel pipe 4, and the outer dimensions of the sealing plate 45 are larger than the dimensions of the insertion section and are adapted to the dimensions of the ordinary section 2 of the anchor hole. That is to say, the sealing plate 45 will not affect the normal insertion of the PSB precision-rolled threaded steel pipe into the anchor hole.

[0059] In some embodiments, the outer circumferential wall and bottom surface of the sealing plate 45 are provided with a sealing layer 46 made of flexible material. The sealing layer 46 made of flexible material facilitates the sealing between the bottom surface of the sealing plate 45 and the stepped surface of the enlarged head section 3, so as to prevent the cement mortar from flowing into the perforated section a and blocking the through hole 42 on the perforated section a when the cement mortar is poured.

[0060] In this invention, the connecting section b also serves as a transitional element. Even if a small amount of cement mortar flows downward along the PSB precision-rolled threaded steel pipe 4 and seeps in, the transitional effect of the connecting section b (i.e., reserving a distance for the cement mortar to seep downward) prevents the cement mortar from flowing down to the perforated section a.

[0061] In some embodiments, the connecting section b of the PSB precision-rolled threaded steel pipe 4 is surrounded by a sealing sleeve 47. The sealing sleeve 47 achieves an interference fit with the insertion section, improving the isolation effect on the cement mortar and preventing the cement mortar during pouring from entering the perforated section a of the PSB precision-rolled threaded steel pipe 4. This ensures the normal use of each through hole 42 on the perforated section a, facilitating subsequent drainage and pressure reduction operations.

[0062] Preferably, the lower end of the sealing sleeve 47 (i.e. the end of the sealing sleeve 47 facing the bottom of the PSB threaded steel pipe 4) is provided with a smooth transition section so that the sealing sleeve 47 can be held downward into the soil when the PSB threaded steel pipe 4 is inserted.

[0063] This invention relates to a PSB anti-buoyancy anchor bolt with active pressure reduction function and its construction method. By designing the PSB threaded steel pipe as hollow (i.e., the PSB threaded steel pipe has cavities arranged along its length), it ensures the PSB threaded steel pipe's anti-buoyancy capability as an anti-buoyancy anchor bolt, thereby ensuring the stability and safety of the structure. When encountering heavy rain or the rainy season, and the groundwater level rises, groundwater enters the cavity of the PSB threaded steel pipe through the perforated section (the through-holes in the perforated section). The water is then pumped out of the PSB threaded steel pipe via water pumps and pipelines, thereby lowering the groundwater level and ensuring it remains within a controllable range (i.e., without damaging the structure of the anti-buoyancy anchor bolt, ensuring the anti-buoyancy anchor bolt can provide sufficient pull-out force for the structure). This invention cleverly integrates the anti-buoyancy anchor plate and groundwater drainage into one unit, ensuring the normal use of the anti-buoyancy anchor bolt while preventing its failure due to rising groundwater levels.

[0064] Compared to existing technologies, the structure of this invention is simple and ingenious. Compared to existing technologies (such as the one described in the background section, application number 2022109266289) that rely on groundwater seepage around the anti-buoyancy anchor to prevent damage, this invention completely solves the problem of groundwater levels affecting the structural safety of anti-buoyancy anchors. It can actively reduce groundwater levels, ensuring that the groundwater level remains within a controllable design range and is not affected by severe weather such as rainy seasons or heavy rains. In the technology document with application number 2022109266289, when encountering severe weather such as heavy rains or rainy seasons, the groundwater level around the anti-buoyancy anchor rises overall, making it impossible to drain the groundwater, leading to irreversible damage to the anti-buoyancy anchor and affecting the safety of the structure. Furthermore, compared to the drainage structure design around the anti-buoyancy anchor in the existing technology (application number 2022109266289), this invention has the advantages of simple structure and quick construction.

[0065] Simultaneously, the anti-buoyancy anchor of this invention can also be used for dewatering foundation pits. During foundation pit excavation, although dewatering wells are arranged around the pit to lower the groundwater level and ensure dryness, these wells are typically located around the perimeter of the pit at a certain distance. After excavation, if rainy season or heavy rain occurs, the groundwater level at the bottom of the pit will rise. Due to the soil structure, it takes time for the groundwater to seep into the dewatering wells. However, after the anti-buoyancy anchor is installed, this invention can directly use PSB precision-rolled threaded steel pipes to drain the groundwater, achieving rapid groundwater removal and shortening the dewatering time. This facilitates the construction of the foundation layer and basement slab, thus reducing the construction period.

Claims

1. A PSB anti-buoyancy anchor with active pressure reduction function, comprising an anchor hole drilled in the soil, wherein the anchor hole comprises, from top to bottom, a normal section (2) and an enlarged head section (3), characterized in that, A PSB precision-rolled threaded steel pipe (4) is inserted into the anchor hole. The PSB precision-rolled threaded steel pipe (4) has a cavity (41). An anchor body (6) is cast between the ordinary section (2) and the enlarged head section (3) of the anchor hole and the outer wall of the PSB precision-rolled threaded steel pipe. The PSB precision-rolled threaded steel pipe (4) includes, from top to bottom, an extension section (d), a cement mortar section (c), a connecting section (b), and a perforated section (a). The cement mortar section (c) is compatible with the ordinary section (2) and the enlarged head section (3) of the anchor hole. The connecting section (b) is located below the enlarged head section (3) of the anchor hole. The perforated section (a) of the PSB precision-rolled threaded steel pipe (4) has several through holes (42) that communicate with the cavity (41) inside the PSB precision-rolled threaded steel pipe. The extension section (d) extends out to the pad layer laid on top of the anchor hole. 7) and the basement floor slab (8) laid on the foundation layer, the top of the extension section (d) is equipped with a valve (5), the valve (5) is a valve with a pore pressure sensor, the top of the extension section (d) is also connected to a pipe (10), the pipe (10) is equipped with a pore pressure gauge (12) and a water pump; the top of the connecting section (b) of the PSB fine-rolled threaded steel pipe (4) is fitted with a sealing plate (45), the sealing plate is threadedly connected to the PSB fine-rolled threaded steel pipe (4), the outer dimensions of the sealing plate (45) are larger than the dimensions of the insertion section and are compatible with the dimensions of the ordinary section (2) of the anchor hole; the outer circumferential wall and bottom surface of the sealing plate (45) are provided with a sealing layer (46) made of flexible material; the outer periphery of the connecting section (b) of the PSB fine-rolled threaded steel pipe (4) is covered with a sealing sleeve (47).

2. The PSB anti-buoyancy anchor bolt with active pressure reduction function according to claim 1, characterized in that, The periphery of the perforated section (a) of the PSB precision-rolled threaded steel pipe (4) is bound with a filter screen (43).

3. The PSB anti-buoyancy anchor bolt with active pressure reduction function according to claim 2, characterized in that, The PSB precision-rolled threaded steel pipe (4) has an annular groove on the periphery of the perforated section (a), and the filter screen (43) is installed in the annular groove and can cover the through hole (42) of the PSB precision-rolled threaded steel pipe.

4. The PSB anti-buoyancy anchor bolt with active pressure reduction function according to claim 1, characterized in that, The lower end of the PSB precision-rolled threaded steel pipe (4) has a pointed tip.

5. The PSB anti-buoyancy anchor bolt with active pressure reduction function according to any one of claims 1-4, characterized in that, The extension section (d) is equipped with anchorages (9) in the area corresponding to the basement floor slab (8).

6. The PSB anti-buoyancy anchor bolt with active pressure reduction function according to claim 5, characterized in that, The cement mortar section (c) of the PSB precision rolled threaded steel pipe (4) is equipped with several bearing plates (44) corresponding to the enlarged head section (3) of the anchor hole.

7. A construction method for a PSB anti-buoyancy anchor bolt with active pressure reduction function as described in any one of claims 1-6, characterized in that, include: (1) The site is leveled and the soil is drilled into the soil to form anchor holes according to the design requirements. The anchor holes include ordinary sections (2) and enlarged head sections (3). (2) The pre-prepared PSB threaded steel pipe (4) is inserted into the anchor hole, and the cement mortar section (c) of the PSB threaded steel pipe (4) corresponds to the ordinary section (2) and the enlarged head section (3) of the anchor hole. The extension section (d) of the PSB threaded steel pipe (4) extends upward out of the soil surface (1). The connecting section (b) and the perforated section (a) of the PSB threaded steel pipe (4) are inserted into the soil below the enlarged head section (3) of the anchor hole. The perforated section (a) of the PSB threaded steel pipe (4) has a through hole (42) that communicates with the cavity (41) of the PSB threaded steel pipe (4). (3) Cement mortar is poured in the area between the anchor hole and the outer wall of the PSB precision threaded steel pipe (4) to form an anchor body (6); (4) Pour the foundation layer (7) and the basement floor slab (8); (5) Install a valve (5) with a pore pressure sensor and a pipe (10) on the top of the PSB fine-rolled threaded steel pipe (4), and then connect a water pump through the pipe (10), on which a pore pressure gauge (12) is installed. (6) The pore pressure sensor sends the detection data to the pore pressure gauge (12). When the value displayed by the pore pressure gauge (12) is greater than or equal to the set value, the pore pressure gauge controls the valve (5) to open and controls the water pump to work to extract groundwater in the PSB fine-rolled threaded steel pipe (4). When the value displayed by the pore pressure gauge is less than the set value, the pore pressure gauge (12) controls the valve (5) to be closed and controls the water pump to stop.

8. The construction method of the PSB anti-buoyancy anchor bolt with active pressure reduction function according to claim 7, characterized in that, The inner wall, outer wall, and through hole wall of the PSB precision rolled threaded steel pipe (4) are all treated with anti-corrosion.

9. The construction method of the PSB anti-buoyancy anchor bolt with active pressure reduction function according to claim 7 or 8, characterized in that, If the area below the enlarged head section (3) of the anchor hole is a hard stratum, when drilling with a drilling rig, drilling continues below the enlarged head section (3) of the anchor hole to form an insertion section. The depth of the insertion section is matched with the sum of the lengths of the connecting section (b) and the perforated section (a) of the PSB precision rolled threaded steel pipe (4).

Images