A flexible anti-floating prefabricated structure and a flexible anti-floating method thereof

Abstract

The application discloses a flexible anti-floating prefabricated structure and a flexible anti-floating method thereof. The structure comprises a lower anchoring section and an upper free section at the top of the lower anchoring section. The lower anchoring section comprises a rotary drill bit and at least one root-shaped cavity. A plurality of root-shaped cavities are sequentially connected in a head-to-tail mode to form an integrated structure. The rotary drill bit is detachably installed at the bottom end of the lowermost root-shaped cavity. The upper free section comprises a support cover plate, a support cylinder, a movable pressing plate, a guide rod, a first return spring and a pull rod. The flexible anti-floating prefabricated structure introduces an elastic deformation component in a force transmission path. When the underground water level rises sharply, the stress concentration at the node of the anti-floating structure bottom plate can be significantly reduced, the safety reserve of the overall anti-floating of the underground structure can be improved, and the deformation requirement of the underground structure can be met by allowing the underground structure to produce a controlled micro-deformation under the action of the sudden increase of the water pressure of the anti-floating structure bottom plate while ensuring the uplift bearing capacity, and transforming the original rigid or semi-rigid constraint into flexible traction.

Description

Technical Field

[0001] This invention belongs to the field of underground structure anti-buoyancy technology, specifically relating to a flexible anti-buoyancy prefabricated structure and its flexible anti-buoyancy method. Background Technology

[0002] In most engineering practices, existing underground projects (such as underground utility tunnels, underground sewage treatment facilities, and underground storage tanks) do not typically employ additional anti-buoyancy components when the bearing capacity of the foundation stratum meets design requirements. Instead, the primary anti-buoyancy measures are usually the self-weight of the underground structure and the unit weight of the overburden. Under normal groundwater levels or conventional unfavorable conditions, this is sufficient to meet the structural requirements for anti-buoyancy stability and normal use. However, with global warming, during the flood season, especially under extreme weather conditions such as heavy rainfall, continuous rainfall, and superimposed rainstorms, the groundwater level may rise significantly in a short period, resulting in a significant increase in the buoyancy force on the underground structure. These extreme conditions often exceed the conventional design water level range, causing the underground structure, which originally relied solely on its own weight for anti-buoyancy, to face insufficient anti-buoyancy safety reserves. When the structure's self-weight is insufficient to resist the buoyancy of groundwater, the bottom plate of the anti-buoyancy structure is prone to arching, increased tensile stress, and even local cracking, leading to structural failure and the risk of the entire structure floating upwards, seriously threatening the safety and stability of underground structure operation.

[0003] Current anti-buoyancy technologies for underground structures often employ rigid or semi-rigid anti-buoyancy piles or anchors to enhance the structure's buoyancy resistance. However, these anti-buoyancy components are often in a low-stress state during actual operation. Once the groundwater level rises sharply, these components are prone to two problems: First, their stress transmission path is highly rigid and lacks ductility. When minor deformations occur, significant stress concentrations easily form at the pile head or anchorage nodes, creating high shear stress zones that can lead to base slab cracking, node failure, and ultimately, structural waterproofing failure. Second, once these anti-buoyancy structures reach their limit state, they are prone to brittle failure, with deformation difficult to recover, thus affecting the overall deformation coordination of the underground structure. Furthermore, cast-in-place anti-buoyancy piles have long construction cycles, involve numerous wet operations on-site, and their quality is greatly affected by construction conditions. In recent years, prefabricated assembly technology has become a new direction for energy conservation, emission reduction, and sustainable development in engineering projects. Prefabricated components can be modularly produced in factories and standardized on-site construction, offering advantages in ensuring project quality and shortening construction periods.

[0004] Therefore, it is necessary to study and develop a flexible anti-buoyancy prefabricated structure and its flexible anti-buoyancy method to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing anti-buoyancy devices by providing a flexible anti-buoyancy prefabricated structure and its flexible anti-buoyancy method.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] A flexible anti-buoyancy prefabricated structure includes a lower anchoring section and an upper free section at the top. The lower anchoring section includes a rotary drill bit and at least one root-shaped cavity. Multiple root-shaped cavities are connected end to end in sequence to form an integral structure. The rotary drill bit is detachably installed at the bottom end of the lowest root-shaped cavity.

[0008] The upper free section includes a support cover plate, a support cylinder, a movable pressure plate, guide rods, a first return spring, and a pull rod. The support cover plate is detachably installed at the top of the uppermost root-shaped cavity. The support cylinder is detachably installed on the top of the support cover plate. The movable pressure plate passes through the bottom of the support cylinder and is fitted inside the support cylinder. The inner cavity of the support cylinder is provided with multiple vertically distributed guide rods, and the bottom end of each guide rod passes through the movable pressure plate and is threaded with a nut for positioning the movable pressure plate. The first return spring is sleeved on the outside of the guide rod and located at... A tie rod is bolted between the movable pressure plate and the inner cavity of the supporting cylinder. An anti-slip component is provided on the outside of the root-shaped cavity. The tie rod includes a rod body and a first anchor plate fixed to the top of the rod body. A second anchor plate is slidably fitted on the outside of the rod body. The rod body passes through the supporting cylinder and is slidably fitted with a through hole. The diameters of the first and second anchor plates are both larger than the rod body. The top surface of the first anchor plate is flush with the top surface of the anti-buoyancy structure bottom plate, and the bottom surface of the second anchor plate is flush with the bottom surface of the anti-buoyancy structure bottom plate.

[0009] Preferably, the rotary drill bit, root-shaped cavity, support cover plate, support cylinder, movable pressure plate, guide rod, first reset spring and pull rod are coaxially assembled; the interior of the rotary drill bit and the root-shaped cavity are both hollow structures, and the rotary drill bit is connected to the inner cavity of the root-shaped cavity.

[0010] Preferably, the rotary drill bit includes a first threaded section and a tapered drill sleeve. The first threaded section is integrally disposed on the top of the tapered drill sleeve. The top and bottom cross-sectional shapes of the tapered drill sleeve are both wedge-shaped, and cutting teeth are provided at the lower edge of the tapered drill sleeve.

[0011] Preferably, the top of the root-shaped cavity is integrally provided with a second threaded section, and a first mounting screw hole is provided at the bottom of the inner wall of the root-shaped cavity, and the first mounting screw hole is threadedly engaged with the second threaded section or the first threaded section.

[0012] The support cover plate has a second mounting screw hole and a third mounting screw hole at its bottom and top, respectively. The second mounting screw hole is threadedly engaged with the second threaded section. The bottom of the support cylinder is integrally provided with a third threaded section, which is threadedly engaged with the third mounting screw hole.

[0013] Preferably, as one embodiment of the anti-slip component, it includes a T-shaped wing ring and a toothed wing ring located on the outer side of the root-shaped cavity, both of which are fixedly connected to the root-shaped cavity; the number of the T-shaped wing ring and the toothed wing ring is set to multiple, and the multiple T-shaped wing rings and toothed wing rings are distributed along the axial direction of the root-shaped cavity, and multiple T-shaped wing rings are distributed at equal intervals between every two toothed wing rings.

[0014] Preferably, as one embodiment of the anti-slip component, it includes a movable wing ring and a toothed wing ring located on the outer side of the root-shaped cavity. Each root-shaped cavity has at least two toothed wing rings, and the toothed wing rings are fixedly connected to the root-shaped cavity. A movable wing ring is slidably fitted between two adjacent toothed wing rings. A plurality of correspondingly distributed retaining seats are fixedly connected to the top of the movable wing ring and the bottom of the toothed wing ring above it. A connecting rod is hinged to the inner side of the retaining seat. A vertical limiting groove is passed through the outer wall of the root-shaped cavity. A telescopic member is passed through the vertical limiting groove, and a movable plate is fixedly connected to the free end of the telescopic member. The side of the movable plate away from the root-shaped cavity is set in a wedge shape. The ends of the two corresponding connecting rods away from the retaining seats are respectively hinged to the top and bottom of the movable plate. A torsion spring is provided at the connection between the connecting rod and the retaining seat so that the movable plate fits against the outer wall of the root-shaped cavity in the initial state.

[0015] Preferably, the telescopic component is configured as a hydraulic cylinder, and the cylinder end of the hydraulic cylinder is slidably engaged with the vertical limiting groove, the output shaft end of the hydraulic cylinder is driven by the movable plate, and the connection end of multiple hydraulic cylinders is provided with a hydraulic drive mechanism for extending and retracting the output shaft of the hydraulic cylinder.

[0016] Preferably, the inner wall of the supporting cylinder is provided with multiple vertically distributed guide grooves, and multiple vertically distributed guide blocks are integrally provided on the outer peripheral wall of the movable pressure plate. The multiple guide grooves and multiple guide blocks are arranged in a one-to-one correspondence. The outer walls of the guide grooves and guide blocks are fitted with a clearance. Sealing felt is embedded in the inner wall of the guide grooves and is pressed between the supporting cylinder and the movable pressure plate. The upper part of the supporting cylinder is provided with at least one first annular groove along the inner wall. An expansion water-stop strip is embedded in the first annular groove and is pressed between the supporting cylinder and the rod. The upper surface of the supporting cylinder is provided with a second annular groove, and a flexible, corrosion-resistant, and waterproof buffer layer is pressed in the second annular groove.

[0017] Preferably, the bottom of the first anchor plate is provided with a plurality of first stiffening plates arranged in a ring array, the top surface of the second anchor plate is provided with a plurality of second stiffening plates arranged in a ring array, and a waterproof flange arranged around the circumference of the rod is provided between the first anchor plate and the second anchor plate; the surfaces of the first anchor plate and the second anchor plate are respectively provided with a plurality of first connecting through holes and a plurality of second connecting through holes arranged in a ring array, and the plurality of first connecting through holes and the plurality of second connecting through holes correspond one-to-one in the vertical direction.

[0018] This invention also provides a flexible anti-buoyancy method for a flexible anti-buoyancy prefabricated structure, comprising the following steps:

[0019] S1. Structural Assembly: Embed the expansion sealing strip into the first annular groove on the upper part of the support cylinder, pass the guide rod through the positioning and mounting hole on the movable pressure plate, and put the first return spring on the guide rod to fix the guide rod in the support cylinder. Insert the pull rod into the support cylinder and embed it into the groove of the movable pressure plate. After the bottom screw hole of the pull rod is positioned with the screw hole of the movable pressure plate, install the connecting screw so that the bottom of the pull rod is fixed in the groove of the movable pressure plate. Rotate the support cover plate to the bottom of the support cylinder.

[0020] S2. Structural Construction: Calculate the required number of root cavity segments based on the required pull-out resistance. Install a rotary drill bit at the end of the last root cavity segment and drill the rotary drill bit and root cavity into the soil or reinforced soil layer in sequence. When the top of the root cavity reaches the design elevation, connect the support cover plate and the upper prefabricated assembly structure to the top of the root cavity through the support cover plate. Construct the anti-buoyancy structure base plate on the top surface of the first anchor plate and the bottom surface of the second anchor plate of the tie rod, and pre-stressed anchor bars are pre-welded and reserved. After the anti-buoyancy structure base plate reaches the design strength, tie the prestressed anchor bars, and further pre-stressed anchor bars in the reserved positions are pre-welded and ground smooth after welding to form an integral part with the anti-buoyancy structure base plate.

[0021] S3. Flexible Anti-buoyancy: When the groundwater level rises sharply, the anti-buoyancy structure base plate will float vertically upward under the increased water pressure. The tie rod is connected to the anti-buoyancy structure base plate, and the tie rod will also move vertically upward. The movable pressure plate will also move vertically upward. When the tie rod drives the movable pressure plate to move, the first return spring will be compressed and deformed. At the same time, when the groundwater level rises, it will exert a vertically upward buoyancy force on the anti-buoyancy structure base plate, causing the first return spring to be continuously compressed. While the first return spring is being continuously compressed, it will also generate a reverse force on the movable pressure plate. This reverse force is finally transmitted to the first anchor plate through the tie rod, thereby providing a downward tensile and compressive reaction force against the anti-buoyancy structure base plate, thus forming a flexible constraint against the anti-buoyancy structure base plate.

[0022] When the groundwater level recovers, the water pressure of the groundwater on the anti-buoyancy structure base plate weakens or disappears. At this time, because the first reset spring is compressed, when the water pressure on the anti-buoyancy structure base plate decreases, under the action of the self-weight of the underground structure, the overlying load, and the compression reaction force generated by the compression of the first reset spring, the tie rod moves vertically downward until it returns to the initial installation state, thus completing the flexible anti-buoyancy prevention of the anti-buoyancy structure base plate.

[0023] The present invention has the following beneficial effects:

[0024] 1. The flexible anti-buoyancy prefabricated structure of the present invention introduces elastic deformation components in the force transmission path. When the groundwater level rises sharply and the water pressure on the bottom plate of the anti-buoyancy structure increases suddenly, it allows the underground structure to produce controlled micro-deformation while ensuring the pull-out bearing capacity. This transforms the original rigid or semi-rigid constraints into flexible traction, which can significantly reduce the stress concentration at the nodes of the bottom plate of the anti-buoyancy structure and improve the overall anti-buoyancy safety reserve of the underground structure.

[0025] 2. The flexible anti-buoyancy prefabricated structure of the present invention has an ingenious structural assembly that can take into account the phenomenon of sudden changes in groundwater level under emergency conditions. When the rapidly changing groundwater pressure disappears, it has a self-returning function. Under the action of the self-weight of the underground structure, the overlying load, and the first reset spring, the underground structure will automatically return to its initial state, thereby improving the overall anti-buoyancy toughness of the underground structure under extreme working conditions.

[0026] 3. The flexible anti-buoyancy prefabricated structure of this invention is a hollow structure or a hollow prestressed structure. It is lightweight, easy to assemble, and can be constructed using small-diameter drilling or expanded-body anchoring methods, resulting in high construction efficiency and minimal impact on the surrounding environment. While ensuring project quality, it offers advantages in material saving, cost reduction, and efficiency improvement. It provides a certain anti-buoyancy safety reserve without requiring further structural counterweights, making it suitable for flexible anti-buoyancy applications in various types of underground projects such as underground integrated pipe corridors, underground sewage treatment facilities, and underground regulating reservoirs.

[0027] 4. The lower anchoring section and the upper free section at the top of the present invention are used together. The lower anchoring section is embedded in the surrounding soil or reinforced soil layer through anti-slip components, so that the contact area between the root cavity and the surrounding soil or reinforced soil layer is larger, thereby improving the stability of the lower anchoring section. In the embodiment, the lower anchoring section is easy to install, connect and adjust quickly, and can adapt to the deformation requirements of underground structures. Attached Figure Description

[0028] Figure 1 This is a three-dimensional view of the overall structure of the flexible anti-buoyancy prefabricated structure provided in Embodiment 1 of the present invention.

[0029] Figure 2 This is a front view of the overall structure of the flexible anti-buoyancy prefabricated structure provided in Embodiment 1 of the present invention.

[0030] Figure 3 for Figure 2 Sectional view along line AA.

[0031] Figure 4 This is a schematic diagram of the connection structure between the tie rod and the supporting cylinder in the flexible anti-buoyancy prefabricated structure provided by the present invention.

[0032] Figure 5 This is a first-view exploded view of the overall structure of the flexible anti-buoyancy prefabricated structure provided in Embodiment 1 of the present invention.

[0033] Figure 6 This is a second-view exploded view of the overall structure of the flexible anti-buoyancy prefabricated structure provided in Embodiment 1 of the present invention.

[0034] Figure 7 This is a three-dimensional view of the root-shaped cavity unit structure provided in Embodiment 1 of the present invention.

[0035] Figure 8 This is a front view of the root-shaped cavity unit structure provided in Embodiment 1 of the present invention.

[0036] Figure 9 This is a half-sectional view of the root-shaped cavity unit structure provided in Embodiment 1 of the present invention.

[0037] Figure 10 This is a three-dimensional view of the root-shaped cavity assembly structure provided in Embodiment 2 of the present invention.

[0038] Figure 11 This is a front view of the root-shaped cavity assembly structure provided in Embodiment 2 of the present invention.

[0039] Figure 12 This is a half-sectional view of the root-shaped cavity assembly structure provided in Embodiment 2 of the present invention.

[0040] Figure 13 This is a diagram illustrating the distribution structure of the flexible anti-buoyancy prefabricated structure, the anti-buoyancy structure base plate, and the surrounding soil or reinforced soil layer provided in Embodiment 1 of the present invention.

[0041] In the diagram: T represents the surrounding soil or reinforced soil layer; D represents the bottom plate of the anti-buoyancy structure.

[0042] 11. Rotary drill bit; 111. First threaded section; 112. Tapered drill sleeve; 113. Cutting teeth; 12. Root-shaped cavity; 121. First mounting screw hole; 122. Second threaded section; 123. T-shaped wing ring; 124. Toothed wing ring; 125. Card holder; 126. Connecting rod; 127. Vertical limiting groove; 128. Telescopic component; 129. Movable plate; 1210. Torsion spring; 1211. Movable wing ring; 13. Support cover plate; 131. Second mounting screw hole; 132. 14. Third mounting screw hole; 15. Support cylinder body; 16. Third threaded section; 17. Guide groove; 18. First annular groove; 19. Second annular groove; 10. Movable pressure plate; 11. Guide block; 12. Guide rod; 13. First return spring; 14. Pull rod; 15. Rod body; 16. First anchor plate; 17. First connecting through hole; 18. Second anchor plate; 19. Second connecting through hole; 10. First stiffening plate; 10. Second stiffening plate. Detailed Implementation

[0043] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0044] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and 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. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0045] like Figures 1-9 The diagram shows a flexible anti-buoyancy prefabricated structure, including a lower anchoring section and an upper free section at the top. The lower anchoring section includes a rotary drill bit 11 and at least one root-shaped cavity 12. Multiple root-shaped cavities 12 are connected end to end in sequence to form an integral structure. The rotary drill bit 11 is detachably installed at the bottom end of the lowest root-shaped cavity 12. The lower anchoring section uses the rotary drill bit 11, the root-shaped cavity 12 and the surrounding soil or reinforced soil layer T to form an anchor body to provide the anti-buoyancy force required by the upper structure.

[0046] The upper free section includes a support cover plate 13, a support cylinder 14, a movable pressure plate 15, a guide rod 16, a first return spring 17, and a pull rod 18. The support cover plate 13 is detachably installed at the top of the root-shaped cavity 12 located at the topmost point. The support cylinder 14 is detachably installed at the top of the support cover plate 13. The movable pressure plate 15 passes through the bottom of the support cylinder 14 and is sleeved inside the support cylinder 14. The inner cavity of the support cylinder 14 is provided with multiple vertically distributed guide rods 16, and the bottom end of the guide rod 16 passes through the movable pressure plate 15 and is threaded with a nut for positioning the movable pressure plate 15. The first return spring 17 is sleeved on the outside of the guide rod 16 and is located between the movable pressure plate 15 and the inner cavity of the support cylinder 14. The pull rod 18 is fixedly connected to the axis of the movable pressure plate 15 by bolts. Specifically, the pull rod 18 includes a rod body 181 and a first anchor plate 182 fixed to the top of the rod body 181, and a second anchor plate 183 is slidably fitted on the outer side of the rod body 181. The rod body 181 passes through the support cylinder 14 and is slidably fitted with a through hole. The diameters of the first anchor plate 182 and the second anchor plate 183 are both larger than that of the rod body 181. Figure 13 As shown, multiple flexible anti-buoyancy prefabricated structures provided in Embodiment 1 of the present invention are embedded in the surrounding soil or reinforced soil layer T, with their tops exposed above the surrounding soil or reinforced soil layer T. An anti-buoyancy structure base plate D is installed at the top of each structure. The top surface of the first anchor plate 182 is flush with the top surface of the anti-buoyancy structure base plate D, and the bottom surface of the second anchor plate 183 is flush with the bottom surface of the anti-buoyancy structure base plate D. In the initial state, the support cylinder 14 is in contact with the lower surface of the anti-buoyancy structure base plate D. When the groundwater level changes, the tie rod 18 is driven by the change in buoyancy and can fluctuate vertically in the upper free section.

[0047] An anti-slip component is provided on the outside of the root cavity 12. The anti-slip component is embedded in the surrounding soil or reinforced soil layer T, which increases the contact area between the root cavity 12 and the surrounding soil or reinforced soil layer T, thereby improving the stability of the lower anchoring section.

[0048] As an optional implementation of the anti-slip component provided in Embodiment 1 of the present invention, such as Figures 7-9 As shown, the anti-slip component includes a T-shaped wing ring 123 and a toothed wing ring 124 located on the outer side of the root-shaped cavity 12. Both the T-shaped wing ring 123 and the toothed wing ring 124 are fixedly connected to the root-shaped cavity 12. Multiple T-shaped wing rings 123 and toothed wing rings 124 are provided, and these multiple T-shaped wing rings 123 and toothed wing rings 124 are distributed along the axial direction of the root-shaped cavity 12. Multiple T-shaped wing rings 123 are evenly spaced between every two toothed wing rings 124. The diameters of the T-shaped wing rings 123 and toothed wing rings 124 are both larger than the diameter of the root-shaped cavity 12. The multiple T-shaped wing rings 123 and toothed wing rings 124 can be distributed in parallel or staggered.

[0049] As an optional implementation of the anti-slip component provided in Embodiment 2 of the present invention, such as Figures 10-12 As shown, the anti-slip assembly includes a movable wing ring 1211 and a toothed wing ring 124 located on the outer side of the root-shaped cavity 12. Each root-shaped cavity 12 has at least two toothed wing rings 124, and the toothed wing rings 124 are fixedly connected to the root-shaped cavity 12. A movable wing ring 1211 is slidably engaged between two adjacent toothed wing rings 124. Multiple corresponding retaining seats 125 are fixedly connected to the top of the movable wing ring 1211 and the bottom of the toothed wing rings 124 above it. A connecting rod 126 is hinged to the inner side of each retaining seat 125. A vertical limiting groove 127 extends through the outer wall of the root-shaped cavity 12. A telescopic member 128 extends through the vertical limiting groove 127, and a movable plate 129 is fixedly connected to the free end of the telescopic member 128. The side of the movable plate 129 away from the root-shaped cavity 12 is wedge-shaped. The ends of the corresponding two connecting rods 126 away from the card seat 125 are respectively hinged to the top and bottom of the movable plate 129. A torsion spring 1210 is provided at the connection between the connecting rod 126 and the card seat 125, so that the movable plate 129 fits against the outer wall of the root-shaped cavity 12 in the initial state. In this embodiment, a portion of the telescopic member 128 is embedded in the vertical limiting groove 127 and moves vertically along the vertical limiting groove 127, which has a certain limiting effect on the main body end of the telescopic member 128.

[0050] Furthermore, in the above technical solution: the telescopic component 128 is configured as a hydraulic cylinder, and the cylinder end of the hydraulic cylinder is slidably engaged with the vertical limiting groove 127. The output shaft end of the hydraulic cylinder is driven by the movable plate 129. The connection end of multiple hydraulic cylinders is provided with a hydraulic drive mechanism for extending and retracting the output shaft of the hydraulic cylinder. By controlling the hydraulic drive mechanism to supply energy to the hydraulic cylinder, its output end pushes the movable plate 129, and multiple movable plates 129 can synchronously expand outward, thereby forming a diffusion support and improving the stability of the lower anchoring section. In addition, the movement of the movable plate 129 can also be achieved by sling pulling, that is, by connecting ropes or wire ropes to the movable wing ring 1211 and pulling it to the top, and by pulling the connecting ropes or wire ropes upward, the movable wing ring 1211 is lifted, and the connecting rods 126 on both sides of the movable plate 129 will change their tilt angle, so that the movable plate 129 can expand outward while moving upward, thus achieving the effect of rapid installation of the root-shaped cavity 12 and improving the stability of the lower anchoring section.

[0051] Furthermore, in the above technical solution: the rotary drill bit 11, the root-shaped cavity 12, the support cover plate 13, the support cylinder 14, the movable pressure plate 15, the guide rod 16, the first return spring 17, and the pull rod 18 are coaxially assembled; the interiors of both the rotary drill bit 11 and the root-shaped cavity 12 are hollow structures, and the inner cavities of the rotary drill bit 11 and the root-shaped cavity 12 are connected. This facilitates the structure's cutting into the soil layer.

[0052] Furthermore, in the above technical solution: the rotary drill bit 11 includes a first threaded section 111 and a tapered drill sleeve 112. The first threaded section 111 is integrally set at the top of the tapered drill sleeve 112. The cross-sectional shape of the top and bottom ends of the tapered drill sleeve 112 is set as a wedge shape, and a cutting tooth 113 is provided at the lower edge of the tapered drill sleeve 112. During construction, the rotary drill bit 11 uses the cutting tooth 113 to scrape the surrounding soil or reinforced soil layer T by rotating around the axis, so as to realize the drilling of the rotary drill bit 11.

[0053] Furthermore, in the above technical solution: a second threaded section 122 is integrally formed on the top of the root-shaped cavity 12, and a first mounting screw hole 121 is formed at the bottom of the inner wall of the root-shaped cavity 12, with the first mounting screw hole 121 threadedly engaging with the second threaded section 122 or the first threaded section 121. The bottom and top of the support cover plate 13 are respectively provided with a second mounting screw hole 131 and a third mounting screw hole 132, with the second mounting screw hole 131 threadedly engaging with the second threaded section 122. The bottom of the support cylinder 14 is integrally formed with a third threaded section 141, with the third threaded section 141 threadedly engaging with the third mounting screw hole 132. This facilitates rapid installation and docking of the structure.

[0054] Furthermore, in the above technical solution: the inner wall of the support cylinder 14 is provided with a plurality of vertically distributed guide grooves 142, and a plurality of vertically distributed guide blocks 151 are integrally provided on the outer peripheral wall of the movable pressure plate 15, and the plurality of guide grooves 142 and the plurality of guide blocks 151 are arranged in a one-to-one correspondence, the outer walls of the guide grooves 142 and the guide blocks 151 are fitted with a clearance, and a sealing felt is embedded in the inner wall of the guide grooves 142, and the sealing felt is pressed between the support cylinder 14 and the movable pressure plate 15.

[0055] Furthermore, in the above technical solution: the upper part of the support cylinder 14 is provided with at least one first annular groove 143 along the inner wall, the first annular groove 143 is embedded with an expansion water-stop strip, and the expansion water-stop strip is pressed between the support cylinder 14 and the rod body 181; the upper surface of the support cylinder 14 is provided with a second annular groove 144, and a flexible corrosion-resistant and waterproof buffer layer is pressed within the second annular groove 144. This flexible corrosion-resistant and waterproof buffer layer has a certain thickness, and in the initial state, it is pressed between the support cylinder 14 and the bottom of the anti-buoyancy structure base plate.

[0056] Furthermore, in the above technical solution: the bottom of the first anchor plate 182 is provided with a plurality of first stiffening plates 184 arranged in a ring array, the top surface of the second anchor plate 183 is provided with a plurality of second stiffening plates 185 arranged in a ring array, and a waterproof flange is provided between the first anchor plate 182 and the second anchor plate 183 and distributed around the circumference of the rod body 181.

[0057] Furthermore, in the above technical solution: the surfaces of the first anchor plate 182 and the second anchor plate 183 are respectively perforated with a plurality of first connecting through holes 1821 and second connecting through holes 1831 arranged in a ring array, and the plurality of first connecting through holes 1821 and the plurality of second connecting through holes 1831 correspond one-to-one in the vertical direction. The first connecting through holes 1821 and the second connecting through holes 1831 are all staggered with the first stiffening plate 184 and the second stiffening plate 185. After the precast structure is installed on site, prestressed anchor bars are welded through the second connecting through hole 1831. The prestressed anchor bars are reserved to pass through the first connecting through hole 1821. After the anti-buoyancy structure base plate D is constructed and cured to the design strength, the prestressed anchor bars are pulled back and further welded through the reserved prestressed anchor bars. After welding, the anchor bars are ground smooth. The tensile strength at the joint is improved by the first anchor plate 182, the second anchor plate 183, the first stiffening plate 184, the second stiffening plate 185 and the welded tie anchor bars, which suppresses the generation of concrete cracks caused by the tensile stress caused by excessive buoyancy.

[0058] This invention also provides a flexible anti-buoyancy method for a flexible anti-buoyancy prefabricated structure, comprising the following steps:

[0059] S1. Structural Assembly: Embed the expansion sealing strip into the first annular groove 143 on the upper part of the support cylinder 14, pass the guide rod 16 through the positioning mounting hole on the movable pressure plate 15, and put the first return spring 17 on the guide rod 16 to fix the guide rod 16 in the support cylinder 14. Insert the pull rod 18 into the support cylinder 14 and embed it into the groove of the movable pressure plate 15. After the bottom screw hole of the pull rod 18 is positioned with the screw hole of the movable pressure plate 15, install the connecting screw so that the bottom of the pull rod 18 is fixed in the groove of the movable pressure plate 15. Rotate the support cover plate 13 to the bottom of the support cylinder 14.

[0060] S2. Structural Construction: Calculate the required number of root cavity 12 segments based on the required pull-out resistance. Install a rotary drill bit 11 at the end of the last root cavity 12 segment. Drill the rotary drill bit 11 and root cavity 12 into the soil or reinforced soil layer in sequence. When the top of the root cavity 12 reaches the design elevation, rotate the support cover plate 13 and the upper prefabricated assembly structure to the top of the root cavity 12 through the support cover plate 13. Construct the anti-buoyancy structure base plate D on the top surface of the first anchor plate 182 and the bottom surface of the second anchor plate 183 of the tie rod 18. Pierce and plug weld the prestressed anchor bars and reserve them. After the anti-buoyancy structure base plate D reaches the design strength, pull the prestressed anchor bars and further pierce and plug weld the prestressed anchor bars in the reserved positions. After welding, grind it smooth so that it forms an integral part with the anti-buoyancy structure base plate D.

[0061] S3. Flexible Anti-buoyancy: When the groundwater level rises sharply, the anti-buoyancy structure base plate D will float vertically upward under the increased water pressure. The tie rod 18 is connected to the anti-buoyancy structure base plate D, and the tie rod 18 will also move vertically upward. The movable pressure plate 15 will also move vertically upward. When the tie rod 18 drives the movable pressure plate 15 to move, the first return spring 17 will undergo compression deformation. At the same time, when the groundwater level rises, it will apply a vertical upward buoyancy force to the anti-buoyancy structure base plate D, causing the first return spring 17 to continuously compress. This is because the rotary drill bit 11 and the root-shaped cavity 12 are anchored in the surrounding soil or reinforced soil layer T. The anchor body formed by the rotary drill bit 11 and the root-shaped cavity 12 and the surrounding soil or reinforced soil layer T will provide the anti-buoyancy force required to suppress the anti-buoyancy structure base plate D. The anchor body can be considered relatively stationary, and the resulting displacement difference will be accumulated on the first return spring 17. While the first return spring 17 is being continuously compressed, it also generates a reverse force on the movable pressure plate 15. This reverse force is ultimately transmitted to the first anchor plate 182 through the tie rod 18, thereby providing a downward tensile and compressive reaction force against the floating structure bottom plate D, and thus forming a flexible constraint against the floating structure bottom plate D.

[0062] When the groundwater level recovers, the water pressure of the groundwater on the anti-buoyancy structure base plate D weakens or disappears. At this time, because the first return spring 17 is compressed, when the water pressure on the anti-buoyancy structure base plate D decreases, under the action of the self-weight of the underground structure, the overlying load, and the compression reaction force generated by the compression of the first return spring 17, the tie rod 18 moves vertically downward until it returns to the initial installation state, thus completing the flexible anti-buoyancy prevention of the anti-buoyancy structure base plate D.

[0063] The above are preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A flexible anti-floated precast structure comprising a lower anchoring segment and an upper free segment at the top thereof, characterized in that, The lower anchoring section includes a rotary drill bit (11) and at least one root-shaped cavity (12). Multiple root-shaped cavities (12) are connected end to end in sequence to form an integral structure. The rotary drill bit (11) can be detachably installed at the bottom end of the root-shaped cavity (12) located at the lowest point. The upper free section includes a support cover plate (13), a support cylinder (14), a movable pressure plate (15), a guide rod (16), a first reset spring (17), and a pull rod (18). The support cover plate (13) is detachably installed at the top of the root-shaped cavity (12) located at the topmost point. The support cylinder (14) is detachably installed at the top of the support cover plate (13). The movable pressure plate (15) passes through the bottom of the support cylinder (14) and is sleeved inside the support cylinder (14). The inner cavity of the support cylinder (14) is provided with multiple vertically distributed guide rods (16), and the bottom end of the guide rod (16) passes through the movable pressure plate (15) and is threaded with a nut for positioning the movable pressure plate (15). The first reset spring (17) is sleeved on the outside of the guide rod (16) and located between the movable pressure plate (15) and the inner cavity of the support cylinder (14). The pull rod (18) is fixedly connected to the axis of the movable pressure plate (15) by bolts. An anti-slip component is provided on the outside of the root-like cavity (12); The tie rod (18) includes a rod body (181) and a first anchor plate (182) fixed to the top of the rod body (181). A second anchor plate (183) is slidably fitted on the outside of the rod body (181). The rod body (181) passes through the support cylinder (14) and is slidably fitted with the through hole. The diameters of the first anchor plate (182) and the second anchor plate (183) are both larger than the rod body (181). The top surface of the first anchor plate (182) is flush with the top surface of the anti-buoyancy structure bottom plate, and the bottom surface of the second anchor plate (183) is flush with the bottom surface of the anti-buoyancy structure bottom plate.

2. The flexible anti-buoyancy prefabricated structure according to claim 1, characterized in that, The rotary drill bit (11), root-shaped cavity (12), support cover plate (13), support cylinder (14), movable pressure plate (15), guide rod (16), first reset spring (17) and pull rod (18) are coaxially assembled; the interior of the rotary drill bit (11) and the root-shaped cavity (12) are both hollow structures, and the rotary drill bit (11) and the inner cavity of the root-shaped cavity (12) are connected.

3. The flexible anti-buoyancy prefabricated structure according to claim 1, characterized in that, The rotary drill bit (11) includes a first threaded section (111) and a tapered drill sleeve (112). The first threaded section (111) is integrally disposed on the top of the tapered drill sleeve (112). The top and bottom cross-sectional shapes of the tapered drill sleeve (112) are both wedge-shaped, and cutting teeth (113) are provided at the lower edge of the tapered drill sleeve (112).

4. The flexible anti-buoyancy prefabricated structure according to claim 1, characterized in that, The top of the root-shaped cavity (12) is integrally provided with a second threaded section (122), and a first mounting screw hole (121) is provided at the bottom of the inner wall of the root-shaped cavity (12), and the first mounting screw hole (121) is threadedly engaged with the second threaded section (122) or the first threaded section (111). The support cover plate (13) has a second mounting screw hole (131) at the bottom and a third mounting screw hole (132) at the top. The second mounting screw hole (131) is threadedly engaged with the second threaded section (122). The bottom of the support cylinder (14) is integrally provided with a third threaded section (141), and the third threaded section (141) is threadedly engaged with the third mounting screw hole (132).

5. A flexible anti-buoyancy prefabricated structure according to claim 1, characterized in that, The anti-slip component includes a T-shaped wing ring (123) and a toothed wing ring (124) located on the outer side of the root cavity (12). Both the T-shaped wing ring (123) and the toothed wing ring (124) are fixedly connected to the root cavity (12). The number of the T-shaped wing ring (123) and the toothed wing ring (124) is set to multiple, and the multiple T-shaped wing rings (123) and toothed wing rings (124) are distributed along the axial direction of the root cavity (12), and multiple T-shaped wing rings (123) are distributed at equal intervals between every two toothed wing rings (124).

6. The flexible anti-buoyancy prefabricated structure according to claim 1, characterized in that, The anti-slip component includes a movable wing ring (1211) and a toothed wing ring (124) located on the outer side of the root-shaped cavity (12). Each root-shaped cavity (12) has at least two toothed wing rings (124), and the toothed wing rings (124) are fixedly connected to the root-shaped cavity (12). A movable wing ring (1211) is slidably fitted between two adjacent toothed wing rings (124). Multiple corresponding retaining seats (125) are fixedly connected to the bottom of the toothed wing rings (124) located at the top of the movable wing ring (1211) and above it. A connecting rod (126) is hinged to the inner side of each retaining seat (125). The root-shaped cavity... A vertical limiting groove (127) runs through the outer wall of the body (12). A telescopic member (128) runs through the vertical limiting groove (127). A movable plate (129) is fixedly connected to the free end of the telescopic member (128). The side of the movable plate (129) away from the root cavity (12) is set as a wedge. The ends of the two connecting rods (126) away from the card seat (125) are respectively hinged to the top and bottom of the movable plate (129). A torsion spring (1210) is provided at the connection between the connecting rod (126) and the card seat (125) so that the movable plate (129) fits against the outer wall of the root cavity (12) in the initial state.

7. A flexible anti-buoyancy prefabricated structure according to claim 6, characterized in that, The telescopic component (128) is configured as a hydraulic cylinder, and the cylinder end of the hydraulic cylinder is slidably engaged with the vertical limiting groove (127). The output shaft end of the hydraulic cylinder is driven by the movable plate (129). The connection end of multiple hydraulic cylinders is provided with a hydraulic drive mechanism for extending and retracting the output shaft of the hydraulic cylinder.

8. A flexible anti-buoyancy prefabricated structure according to claim 1, characterized in that, The inner wall of the support cylinder (14) is provided with a plurality of vertically distributed guide grooves (142), and a plurality of vertically distributed guide blocks (151) are integrally provided on the outer peripheral wall of the movable pressure plate (15). The plurality of guide grooves (142) and the plurality of guide blocks (151) are arranged in a one-to-one correspondence. The outer walls of the guide grooves (142) and the guide blocks (151) are fitted with a clearance. Sealing felt is embedded in the inner wall of the guide grooves (142), and the sealing felt is pressed between the support cylinder (14) and the movable pressure plate (15). The upper part of the support cylinder (14) is provided with at least one first annular groove (143) around the inner wall. An expansion water-stop strip is embedded in the first annular groove (143) and the expansion water-stop strip is pressed between the support cylinder (14) and the rod (181). A second annular groove (144) is provided around the upper surface of the support cylinder (14), and a flexible corrosion-resistant and waterproof buffer layer is pressed in the second annular groove (144).

9. A flexible anti-buoyancy prefabricated structure according to claim 1, characterized in that, The bottom of the first anchor plate (182) is provided with a plurality of first stiffening plates (184) arranged in a ring array, the top surface of the second anchor plate (183) is provided with a plurality of second stiffening plates (185) arranged in a ring array, and a waterproof flange is provided between the first anchor plate (182) and the second anchor plate (183) and distributed around the circumference of the rod body (181). The first anchor plate (182) and the second anchor plate (183) are respectively perforated by a plurality of first connecting through holes (1821) and second connecting through holes (1831) arranged in a ring array, and the plurality of first connecting through holes (1821) and the plurality of second connecting through holes (1831) correspond one-to-one in the vertical direction.

10. The flexible anti-buoyancy method for a flexible anti-buoyancy prefabricated structure as described in claim 8, characterized in that, Includes the following steps: S1. Structural assembly: The expansion sealing strip is embedded in the first annular groove (143) on the upper part of the support cylinder (14), the guide rod (16) is passed through the positioning mounting hole on the movable pressure plate (15), the first reset spring (17) is sleeved on the guide rod (16), the guide rod (16) is fixed in the support cylinder (14), the pull rod (18) is inserted into the support cylinder (14) and embedded in the groove of the movable pressure plate (15), after the bottom screw hole of the pull rod (18) is positioned with the screw hole of the movable pressure plate (15), the connecting screw is installed so that the bottom of the pull rod (18) is fixed in the groove of the movable pressure plate (15), and the support cover plate (13) is rotated and connected to the bottom of the support cylinder (14); S2, Structural Construction: Calculate the required number of segments of the root cavity (12) according to the required pull-out force. Install a rotary drill bit (11) at the end of the last root cavity (12). Drill the rotary drill bit (11) and the root cavity (12) into the soil or reinforced soil layer in sequence. When the top of the root cavity (12) reaches the design elevation, connect the support cover plate (13) and the upper prefabricated assembly structure to the top of the root cavity (12) through the support cover plate (13). Construct the anti-buoyancy structure base plate on the top surface of the first anchor plate (182) and the bottom surface of the second anchor plate (183) of the tie rod (18). Pierce and plug weld and reserve the prestressed anchor bars. After the anti-buoyancy structure base plate reaches the design strength, pull the prestressed anchor bars and further pierce and plug weld the prestressed anchor bars in the reserved parts. After welding, grind it flat so that it forms an integral part with the anti-buoyancy structure base plate. S3, Flexible Anti-buoyancy: When the groundwater level rises sharply, the bottom plate of the anti-buoyancy structure will float vertically upward under the action of increased water pressure. The tie rod (18) is connected to the bottom plate of the anti-buoyancy structure. The tie rod (18) will also move vertically upward, and the movable pressure plate (15) will also move vertically upward. When the tie rod (18) drives the movable pressure plate (15) to move, the first return spring (17) will be compressed and deformed. At the same time, when the groundwater level rises, it will apply a vertical upward buoyancy force to the bottom plate of the anti-buoyancy structure, causing the first return spring (17) to be continuously compressed. While the first return spring (17) is being continuously compressed, it will also generate a reverse force on the movable pressure plate (15). This reverse force is finally transmitted to the first anchor plate (182) through the tie rod (18), thereby providing a downward tensile and compressive reaction force to the bottom plate of the anti-buoyancy structure, and thus forming a flexible constraint on the bottom plate of the anti-buoyancy structure. When the groundwater level recovers, the water pressure of the groundwater on the anti-buoyancy structure base plate weakens or disappears. At this time, due to the compression of the first reset spring (17), when the water pressure on the anti-buoyancy structure base plate decreases, under the action of the self-weight of the underground structure, the overlying load, and the compression reaction force generated by the compression of the first reset spring (17), the tie rod (18) moves vertically downward until it returns to the initial installation state, thus completing the flexible anti-buoyancy prevention of the anti-buoyancy structure base plate.

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