A reinforcing structure for local anti-floating failure of a bottom plate

Abstract

The utility model discloses a kind of reinforcing structure of bottom plate local anti-floating failure, it is related to building construction technology field, including the reinforced concrete slab being set on the bottom plate of original basement, and the anti-floating anchor rod passing through bottom plate and anchoring into foundation;Waterproof layer is arranged between the reinforced concrete slab and bottom plate;The top of the anti-floating anchor rod is anchored in the reinforced concrete slab, double-layer steel mesh is arranged in the reinforced concrete slab;The anti-floating anchor rod includes outer sleeve tube and inner rod of coaxial sliding arrangement, the bottom of the outer sleeve tube is provided with multiple split joints;The top of the inner rod is also provided with support rod, two groups of steel reinforcement suspension mechanism are slidably arranged on the support rod, for suspending double-layer steel mesh.The utility model significantly improves anchoring reliability in silt, sandy soil and other poor strata and the ultimate uplift bearing capacity of single anchor rod.

Description

Technical Field

[0001] This utility model relates to the field of building construction technology, and in particular to a reinforcement structure for local anti-buoyancy failure of the base plate. Background Technology

[0002] As urban construction continues to expand underground, multi-story basements have become a standard design feature. When the basement floor is below the groundwater level, it will be subjected to significant buoyancy from groundwater for extended periods. To counteract this buoyancy, anti-buoyancy anchors are commonly used as the primary anti-buoyancy measure in engineering projects. Anti-buoyancy anchors provide pull-out resistance by anchoring their rods to stable strata beneath the floor and utilizing the bond friction between the rod and the borehole wall mortar, and between the mortar and the stratum.

[0003] However, traditional anti-buoyancy anchors (usually formed by binding several steel bars together, inserting them into a drilled hole, and then injecting cement grout) have significant limitations in anti-buoyancy performance in practical engineering, especially in soft soil layers (such as silt and sand). This is mainly because their pull-out resistance depends primarily on the bond friction between the grout and the surrounding soil. In soft soil, this friction value is low and highly variable. When the water level rises sharply and the buoyancy increases, the bond surface between the anchor and the soil is prone to slippage or even complete pull-out, leading to localized anti-buoyancy failure. This failure can cause the base slab to heave and crack, which in turn damages the waterproofing layer, causing leakage and seriously threatening the safety and durability of underground structures.

[0004] Furthermore, during the construction of anti-buoyancy reinforcement, when binding double-layer steel mesh on the upper part of the base slab, the traditional approach is to temporarily find pads, square timbers, etc. on site for support and positioning. This method has significant drawbacks: First, the support height is not uniform, making it difficult to ensure the design spacing and flatness of the two layers of steel mesh; second, the stability of temporary supports is poor, and they are prone to displacement under the impact of personnel movement and concrete pouring, causing the steel mesh to sink or deform, making it unable to be in the correct stress position in the concrete slab, which seriously weakens the load-bearing capacity of the newly added structural slab. Utility Model Content

[0005] The purpose of this invention is to solve the problems of poor anchoring reliability and poor support stability during steel mesh pouring in the prior art, and to propose a reinforcement structure for local anti-buoyancy failure of the base plate.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A reinforcement structure for localized buoyancy failure of a base slab includes a reinforced concrete slab placed on top of the existing basement base slab, and an anti-buoyancy anchor rod that passes through the base slab and is anchored into the foundation; a waterproof layer is provided between the reinforced concrete slab and the base slab; the top end of the anti-buoyancy anchor rod is anchored inside the reinforced concrete slab, and a double-layer steel mesh is provided inside the reinforced concrete slab.

[0008] The anti-buoyancy anchor bolt includes an outer sleeve and an inner rod that are coaxially slidably arranged. The bottom of the outer sleeve has multiple slits, and the inner side of the bottom of the outer sleeve has an inner chamfer. The bottom of the inner rod is provided with a spindle-shaped cone, and the upper end of the cone fits into the inner chamfer. The top of the inner rod extends beyond the outer sleeve and is provided with a lifting mechanism between it and the outer sleeve. The lifting mechanism can push the inner rod upward, causing the cone to slide along the inner chamfer, and expanding the bottom of the outer sleeve outward along the slits to form an inverted cone structure.

[0009] The top of the inner rod is also provided with a support rod, on which two sets of steel bar suspension mechanisms are slidably mounted for suspending the double-layer steel mesh.

[0010] Preferably, the lifting mechanism includes a first support pad installed on the top of the outer tube and a second support pad installed on the top of the inner rod. Two sets of mounting ears are installed on the facing sides of the first and second support pads. A support rod is rotatably mounted on the mounting ear. Two support rods in the same set are rotatably connected to the same rotating sleeve. A threaded rod is inserted between the two rotating sleeves. The threaded rod is rotatably connected to one of the rotating sleeves and threadedly connected to the other rotating sleeve.

[0011] Preferably, the rebar suspension mechanism includes two rotating rings that are rotatably connected to each other on the support rod and sleeved on the support rod. The rotating rings have upward-opening support plates installed on their sides. The outer circumferential surface of the support rod has multiple equally spaced annular grooves and a through groove that axially penetrates all the annular grooves. The inner wall of the rotating rings is provided with a locking block that matches the cross-section of the through groove. When the locking blocks in both rotating rings rotate to the position of the through groove, the height can be adjusted by axial displacement.

[0012] Preferably, the waterproof layer comprises a cement mortar leveling layer and an SBS waterproof membrane layer arranged sequentially from bottom to top.

[0013] Preferably, the reinforced concrete slab is connected to the structural columns and shear walls of the basement by means of rebar installation.

[0014] This utility model has the following advantages compared with the prior art:

[0015] 1. This utility model achieves controllable expansion of the bottom of the anti-buoyancy anchor rod within the hole by using a coaxially sliding outer tube and inner rod. The outer tube has a split bottom and an inner chamfer, forming an inverted cone structure. This transforms the pull-out resistance mechanism of the anti-buoyancy anchor rod from the traditional "surface friction" that depends on soil conditions to a reliable "mechanical interlocking". The inverted cone structure is embedded in the surrounding soil and grout, so that the tensile strength of the anti-buoyancy anchor rod no longer depends entirely on the frictional resistance of the soft soil. This significantly improves the anchoring reliability and the ultimate pull-out bearing capacity of a single anchor rod in poor strata such as silt and sand.

[0016] 2. The jacking mechanism of this utility model provides a slow, continuous, and torque-controllable jacking method. By rotating the threaded rod, the inner rod can be smoothly pushed upwards by a predetermined stroke, ensuring that the cone head can evenly and fully expand the bottom of the outer sleeve, avoiding damage to the rod or soil that may be caused by impact expansion. This structure is easy to operate, requires little working space, and is particularly suitable for use in narrow basement environments. During the jacking process, construction personnel can clearly judge whether the anchor has been successfully expanded by the height of the inner rod extension, effectively ensuring the final forming quality of each anti-buoyancy anchor and avoiding the quality hazards caused by problems such as insufficient grouting in traditional anchors.

[0017] 3. This utility model features a support rod with a steel bar suspension mechanism at the top of the inner rod of the anti-buoyancy anchor rod, enabling rapid and precise height adjustment and reliable locking. Two mutually perpendicular support plates can stably support the longitudinal and transverse bars of the double-layer steel mesh, ensuring that they maintain the designed position and spacing before and during concrete pouring. This eliminates the instability of traditional temporary pads, ensuring that the protective layer thickness and interlayer distance of the double-layer steel mesh meet design requirements, thereby guaranteeing the structural performance of the newly added concrete slab. At the same time, it combines the anchor rod construction and steel mesh support processes into one, reducing material waste and process handover, significantly improving construction efficiency, and reducing the uncertainty of human operation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of a reinforcement structure for local anti-buoyancy failure of the bottom plate proposed in this utility model;

[0019] Figure 2 This is a schematic diagram of the reinforcement structure arrangement for local anti-buoyancy failure of the bottom plate proposed in this utility model.

[0020] Figure 3 for Figure 1 A magnified structural diagram of part A in the middle;

[0021] Figure 4 This is a schematic diagram of the anti-buoyancy anchor rod in a reinforcement structure for local anti-buoyancy failure of the base plate proposed in this utility model;

[0022] Figure 5 for Figure 4 A magnified structural diagram of part B in the middle section;

[0023] Figure 6 This is a schematic diagram of the structure of the anti-buoyancy anchor in its initial state.

[0024] Figure 7 A schematic diagram of the structure under anti-buoyancy anchor reinforcement.

[0025] Figure 8This is a schematic diagram of the steel bar suspension mechanism in a reinforcement structure for local anti-buoyancy failure of the base plate proposed in this utility model.

[0026] In the diagram: 1. Base plate; 2. Reinforced concrete slab; 21. Double-layer steel mesh; 3. Anti-buoyancy anchor; 31. Outer sleeve; 311. Dividing crack; 312. Inner edge chamfer; 32. Inner rod; 321. Conical head; 33. Lifting mechanism; 331. First support pad; 332. Second support pad; 333. Mounting ear; 334. Support rod; 335. Rotating sleeve; 336. Threaded rod; 34. Support rod; 341. Ring groove; 342. Through groove; 35. Steel bar suspension mechanism; 351. Rotating ring; 352. Support plate; 353. Locking block; 4. Waterproof layer; 41. Cement mortar leveling layer; 42. SBS waterproof membrane layer. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0028] Reference Figure 1-3 A reinforcement structure for localized buoyancy failure of the base slab includes a newly added reinforced concrete slab 2 placed on the existing basement base slab 1. The reinforced concrete slab 2 is a key component for resisting buoyancy. It has a double-layer steel mesh 21 with a diameter of 20mm and a spacing of 200mm×200mm inside to provide sufficient structural strength and crack resistance. The reinforced concrete slab 2 is reliably connected to the existing structural columns or shear walls in the basement by means of rebar installation, thereby transferring part of the buoyancy to the main structure and forming an overall anti-buoyancy system.

[0029] Between the newly added reinforced concrete slab 2 and the original base slab 1, a continuous waterproof layer 4 is installed. The waterproof layer 4 consists of a 25mm thick cement mortar leveling layer 41 and an SBS waterproof membrane layer 42 from bottom to top. Its core function is to form a reliable isolation barrier. The cement mortar leveling layer 41 is used to fill the uneven areas of the base slab 1 and provide a flat base surface for the construction of the SBS waterproof membrane layer 42. The SBS waterproof membrane layer 42 can effectively prevent groundwater vapor from seeping up through the micro-cracks of the original base slab, protect the newly added reinforced concrete slab 2 from water erosion, and ensure its long-term durability.

[0030] The core of this invention is the anti-buoyancy anchor 3 that passes through the base plate 1 and is anchored into the foundation. The top of the anti-buoyancy anchor 3 is anchored inside the reinforced concrete slab 2.

[0031] Reference Figure 3-8The anti-buoyancy anchor 3 is not a traditional straight anchor, but includes an outer sleeve 31 and an inner rod 32 that are coaxially slidably arranged. The bottom of the outer sleeve 31 has multiple slits 311, and the inner side of the bottom of the outer sleeve 31 has an inner edge chamfer 312. The bottom of the inner rod 32 is provided with a spindle-shaped cone 321, and the upper end of the cone 321 fits snugly with the inner edge chamfer 312. The top of the inner rod 32 extends beyond the outer sleeve 31 and is provided with a lifting mechanism 33 between it and the outer sleeve 31. The spindle-shaped cone 321 is easy to insert into the drill hole. After the anti-buoyancy anchor 3 is inserted into the drill hole, the inner rod 32 is pushed upward a small section by operating the lifting mechanism 33 provided at the top of the anti-buoyancy anchor 3. During the predetermined process, the cone head 321 is forced to slide upward along the inner chamfer 312. Due to its spindle-shaped design, a huge radial force is generated. This force forces the bottom of the outer sleeve 31 to expand and bulge outward along the split crack 311, eventually forming an inverted cone structure at the bottom of the borehole that is larger than the diameter of the anti-buoyancy anchor rod 3. After the cement grout is injected, this inverted cone structure forms a strong mechanical interlock with the surrounding soil and grout. Its pull-out resistance principle changes from the traditional "friction resistance" that depends on soil conditions to a reliable "shape resistance", thereby greatly improving the anchoring reliability in soft soil layers and the ultimate pull-out bearing capacity of a single anchor rod.

[0032] Reference Figure 3-8 The lifting mechanism 33 includes a first support pad 331 installed on the top of the outer sleeve 31 and a second support pad 332 installed on the top of the inner rod 32. Two sets of mounting ears 333 are installed on the facing sides of the first support pad 331 and the second support pad 332. Support rods 334 are rotatably mounted on the mounting ears 333. Two support rods 334 in the same set are rotatably connected to the same rotating sleeve 335. A threaded rod 336 is inserted between the two rotating sleeves 335. The threaded rod 336 is rotatably connected to one of the rotating sleeves 335 and to the other rotating sleeve 332. 5. Threaded connection: To avoid interference with the movement of the threaded rod 336, the inner rod 32 has a through groove in the center for the threaded rod 336 to pass through. When the threaded rod 336 is screwed, one rotating sleeve 335 is driven by the thread while the other rotates freely. The two rotating sleeves 335 will move towards or away from each other, thereby smoothly lifting or lowering the second support pad 332 through the lever action of the support rod 334, which drives the inner rod 32 to move. This provides a slow, continuous and torque-controllable lifting method, which is labor-saving and ensures that the bottom of the anchor rod can be expanded evenly and fully.

[0033] The top of the inner rod 32 is also provided with a support rod 34, and two sets of steel bar suspension mechanisms 35 are slidably arranged on the support rod 34 for suspending the double-layer steel bar mesh 21.

[0034] Reference Figure 3-8The rebar suspension mechanism 35 includes two rotating rings 351 that are rotatably connected to and sleeved on the support rod 34. One rotating ring 351 has a protruding ring on its side wall, and the other rotating ring 351 has a mating groove on its side wall. The protruding ring and the mating groove are rotatably engaged to achieve the rotational engagement of the two rotating rings 351. The side of the rotating ring 351 is equipped with an upward-opening support plate 352, which can support the rebar and provide support for the laying of the double-layer rebar mesh 21. The outer circumferential surface of the support rod 34 has multiple equally spaced annular grooves 341 and a through groove 342 that axially penetrates the annular grooves 341. The inner wall of the rotating ring 351 is provided with a locking block 353 that matches the cross-section of the through groove 342. When the locking blocks 353 in both rotating rings 351 are rotated to the position of the through groove 342, the height can be adjusted by axial displacement.

[0035] Specifically, when the suspension height needs to be adjusted, the construction personnel can simultaneously rotate the two rotating rings 351 so that the locking blocks 353 inside are aligned with the through grooves 342 on the support rod 34. At this time, the entire suspension structure can slide freely up and down along the through grooves 342. When it slides to the predetermined position of the annular groove 341, the two rotating rings 351 need to be rotated and adjusted so that their support plates 352 are roughly perpendicular to each other (one is used to support the longitudinal reinforcement and the other is used to support the transverse reinforcement). At this time, the two locking blocks 353 will also rotate, thereby disengaging from the through grooves 342 and locking into the corresponding annular grooves 341. Due to the limiting effect of the annular grooves 341, the suspension structure is firmly locked at this height and cannot be easily moved. This completely eliminates the instability of traditional temporary pads and can quickly and accurately establish the support system of the double-layer steel mesh 21, ensuring that the thickness of the steel reinforcement protective layer and the interlayer distance fully meet the design requirements, laying a solid foundation for the subsequent concrete pouring quality.

[0036] When working, follow these steps:

[0037] S1. Dewatering operation: Install manholes with a diameter of 600mm and a depth of 12.5m around the failed part of the original basement floor slab 1. Through continuous dewatering, the groundwater level will be stably lowered to 500mm below the bottom surface of floor slab 1, creating conditions for subsequent dry construction.

[0038] S2. Construction of anti-buoyancy anchor rod 3: After the water level meets the requirements, points are laid out on the base plate 1 at a horizontal and vertical spacing of 1.5m. A drill with a diameter of 150mm is drilled using a casing drill. Then, the assembled anti-buoyancy anchor rod 3 is inserted into the drill hole to the design depth. Next, the threaded rod 336 of the lifting mechanism 33 is operated. Through its transmission, the inner rod 32 is smoothly pushed upward, so that the cone head 321 opens the bottom of the outer sleeve 31 to form a solid inverted cone structure. Finally, cement slurry is injected into the drill hole under pressure to fill the gap between the rod body and the hole wall, forming a complete anchor body.

[0039] S3. Waterproofing layer construction: After all the anti-buoyancy anchors 3 are installed, thoroughly clean the surface of the base plate 1, and then construct a 25mm thick cement mortar leveling layer 41. After it hardens, lay the SBS waterproof membrane layer 42 on it and seal the joints.

[0040] S4. Rebar Mesh Binding: Using the pre-installed rebar suspension mechanism 35 at the top of the anti-buoyancy anchor rod 3, adjust and lock the height of the rotating ring 351 according to the design elevation, place the longitudinal and transverse rebars of the double-layer rebar mesh 21 on the mutually perpendicular support plates 352, and then bind and fix them. At the same time, at the junction of the reinforced concrete slab 2 and the existing structural columns and walls, connect them by rebar installation to enhance the overall integrity.

[0041] S5. Concrete pouring: Set up the side formwork and pour waterproof concrete with a strength grade of not less than C30. Vibrate and compact it. The thickness of the newly added reinforced concrete slab 2 should be controlled between 300mm and 500mm to ensure that it has sufficient rigidity and strength to distribute and transmit buoyancy.

[0042] S6. Well sealing and curing: When the concrete slab strength measured on site reaches more than 75% of the design strength, the well dewatering can be stopped, and the dewatering well should be sealed tightly with early-strength and fast-hardening concrete immediately. The entire project needs to be cured for 28 days before it can be considered officially completed.

Claims

1. A reinforcement structure for localized buoyancy failure of a base plate, characterized in that, It includes a reinforced concrete slab (2) set on the original basement floor slab (1), and an anti-buoyancy anchor rod (3) passing through the floor slab (1) and anchored into the foundation; a waterproof layer (4) is provided between the reinforced concrete slab (2) and the floor slab (1); the top of the anti-buoyancy anchor rod (3) is anchored inside the reinforced concrete slab (2), and a double-layer steel mesh (21) is provided inside the reinforced concrete slab (2); The anti-buoyancy anchor (3) includes an outer tube (31) and an inner rod (32) that are coaxially slidably arranged. The bottom of the outer tube (31) is provided with multiple splits (311), and the inner side of the bottom of the outer tube (31) has an inner edge chamfer (312). The bottom of the inner rod (32) is provided with a spindle-shaped cone (321), and the upper end of the cone (321) fits in close contact with the inner edge chamfer (312). The top of the inner rod (32) extends beyond the outer tube (31) and a lifting mechanism (33) is provided between the inner rod (32) and the outer tube (31). The lifting mechanism (33) can push the inner rod (32) upward, so that the cone (321) slides along the inner edge chamfer (312), and the bottom of the outer tube (31) expands outward along the splits (311) to form an inverted cone structure. The top of the inner rod (32) is also provided with a support rod (34), and two sets of steel bar suspension mechanisms (35) for suspending the double-layer steel bar mesh (21) are slidably provided on the support rod (34).

2. The reinforcement structure for localized anti-buoyancy failure of the base plate according to claim 1, characterized in that, The lifting mechanism (33) includes a first support pad (331) installed on the top of the outer sleeve (31) and a second support pad (332) installed on the top of the inner rod (32). Two sets of mounting ears (333) are installed on the opposite side of the first support pad (331) and the second support pad (332). A support rod (334) is rotatably mounted on the mounting ear (333). The two support rods (334) in the same set are rotatably connected to the same rotating sleeve (335). A threaded rod (336) is inserted between the two rotating sleeves (335). The threaded rod (336) is rotatably connected to one of the rotating sleeves (335) and threadedly connected to the other rotating sleeve (335).

3. The reinforcement structure for localized anti-buoyancy failure of the bottom plate according to claim 1, characterized in that, The steel bar suspension mechanism (35) includes two rotating rings (351) that are rotatably connected to each other on the support rod (34) and sleeved on the support rod (34). The rotating rings (351) have support plates (352) with openings facing upwards installed on their sides. The outer circumferential surface of the support rod (34) is provided with multiple equally spaced annular grooves (341) and a through groove (342) that axially penetrates all the annular grooves (341). The inner wall of the rotating rings (351) is provided with a locking block (353) that matches the cross section of the through groove (342). When the locking blocks (353) in both rotating rings (351) are rotated to the position of the through groove (342), the height can be adjusted by axial displacement.

4. The reinforcement structure for localized anti-buoyancy failure of the bottom plate according to claim 1, characterized in that, The waterproof layer (4) includes a cement mortar leveling layer (41) and an SBS waterproof membrane layer (42) arranged sequentially from bottom to top.

5. The reinforcement structure for localized anti-buoyancy failure of the bottom plate according to claim 1, characterized in that, The reinforced concrete slab (2) is connected to the structural columns and shear walls of the basement by means of rebar installation.

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