Underground garage anti-floating pile and bottom plate integrated connection structure and construction method
By forming a connection structure with a flexible energy dissipation section and a rigid enlarged head between the anti-buoyancy pile and the base plate, and combining it with digital monitoring and management, the problems of excessive stiffness and insufficient flexibility at the connection node between the anti-buoyancy pile and the base plate were solved, thus achieving effective transmission of anti-buoyancy force and structural safety throughout its entire life cycle.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 十七冶安徽建设有限公司
- Filing Date
- 2026-04-27
- Publication Date
- 2026-07-31
AI Technical Summary
The existing anti-buoyancy piles and base plate connection nodes have problems of excessive stiffness and insufficient flexibility, which leads to stress concentration at the junction of the pile top and the base plate under the repeated action of water buoyancy, resulting in concrete cracking and leakage channels. The treatment is difficult and costly.
The underground garage adopts an integrated connection structure between the anti-buoyancy piles and the base slab. By opening a central reserved hole in the middle of the anti-buoyancy pile body, pre-embedding connecting steel bars, and installing a detachable double water-stop grouting ring and rubber water-stop strip on the pile top, a flexible energy dissipation section is formed. Combined with high-pressure grouting, a rigid enlarged head is formed to increase the mechanical interlocking force. The strain is monitored in real time by a prestressed sensor to achieve digital management.
It effectively avoids stress concentration, prevents concrete cracking, ensures effective transfer of anti-buoyancy force, provides structural safety and waterproof performance throughout the entire life cycle, and reduces leakage risk and construction costs.
Smart Images
Figure CN122485293A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of building construction technology, specifically to the integrated connection structure and construction method of anti-buoyancy piles and base slab for underground parking garages. Background Technology
[0002] With the increasing development of urban underground space and the continuous increase in the depth of underground parking garages, the buoyancy problem of groundwater levels on structures is becoming increasingly prominent, especially in coastal and riverside areas where seasonal water level fluctuations are drastic. Therefore, the anti-buoyancy design of underground structures has become a key factor affecting project safety and cost. Currently, conventional anti-buoyancy measures mainly include anti-buoyancy piles and anti-buoyancy anchors.
[0003] However, existing anti-buoyancy pile and base slab connection nodes generally suffer from the defects of "excessive stiffness and insufficient flexibility". The traditional approach is to directly anchor the pile head reinforcement into the base slab or use simple rebar installation. For example, CN202123287930.4 describes a top locking anchoring device for a pressure-type anti-buoyancy pile, which temporarily tensions and locks the unbonded steel strand to the top of the locking short steel pipe before the foundation is poured using anchor plates and anchorages; after the foundation is poured, the steel strand is permanently anchored inside the foundation using the pre-installed anchor plates and anchorages.
[0004] This rigid connection method, under the repeated action of buoyancy, is prone to stress concentration at the junction of the pile top and the base slab, leading to concrete cracking and subsequent leakage channels. Once the waterproof layer is damaged, groundwater will seep into the garage through the gaps between the reinforcing steel or the pile body and the base slab, making remediation extremely difficult and costly.
[0005] To address the aforementioned issues, a solution is proposed: an integrated connection structure and construction method for anti-buoyancy piles and the base slab in underground parking garages. Summary of the Invention
[0006] To address the aforementioned technical problems, this invention provides an integrated connection structure and construction method for anti-buoyancy piles and base slabs in underground parking garages. This solves the common defects of "excessive stiffness and insufficient flexibility" in existing anti-buoyancy pile-to-base-slab connection nodes. Traditional methods involve directly anchoring the pile head reinforcement into the base slab or using simple rebar installation. This rigid connection method, under the repeated action of buoyancy, easily leads to stress concentration at the junction of the pile top and the base slab, causing concrete cracking and subsequently creating leakage channels. Once the waterproofing layer is damaged, groundwater can seep into the garage through the gaps between the reinforcement or pile body and the base slab, resulting in extremely difficult and costly remediation.
[0007] To achieve the above objectives, the technical solution adopted in this invention is as follows: an integrated connection structure between the anti-buoyancy pile and the base slab of an underground parking garage, comprising an anti-buoyancy pile body, a central reserved hole in the middle of the anti-buoyancy pile body, a connecting steel bar bundle pre-embedded inside the central reserved hole, a detachable double water-stop grouting ring installed on the outer side of the top of the anti-buoyancy pile body, a water-contact rubber water-stop strip installed between the detachable double water-stop grouting ring and the anti-buoyancy pile body, at least two inwardly recessed annular corrugated grooves provided on the inner wall of the central reserved hole, a grouting channel provided above the detachable double water-stop grouting ring, at least three sets of prestress sensors provided inside the central reserved hole, a cushion layer provided on the outer side of the anti-buoyancy pile body, a waterproof layer provided above the cushion layer, and a base slab provided above the waterproof layer.
[0008] The construction method for the integrated connection between the anti-buoyancy piles and the foundation slab of the underground parking garage includes:
[0009] S1: Precast concrete anti-buoyancy pile body with central reserved hole, and install a detachable double water-stop grouting ring on the outer side of the top of the pile body;
[0010] S2: Insert the prestressed connecting steel bar bundle into the central reserved hole and perform the first limiting grouting. The top surface of the grouting is controlled at a position 200mm to 350mm lower than the design elevation of the pile top, so as to form a flexible energy dissipation section with elastic-plastic deformation capacity at the pile top.
[0011] S3: Construct the foundation and waterproof layer, and seal the waterproof layer to the outer wall of the grouting ring;
[0012] S4: Tie the bottom slab reinforcement and mechanically connect the bottom slab reinforcement to the top end of the prestressed connecting reinforcement bundle extending from the top of the flexible energy dissipation section;
[0013] S5: Erect formwork and pour concrete for the base slab to form the base slab structure;
[0014] S6: After the initial setting of the bottom plate concrete, a second high-pressure grouting is performed on the pile top area through the grouting channel pre-embedded in the grouting ring or pile body. The grout fills the upper enlarged space of the central reserved hole and the gap around the flexible energy dissipation section. After solidification, a rigid enlarged head embedded in the bottom plate is formed inside the bottom plate.
[0015] S7: Perform strain monitoring on the connection nodes and feed the monitoring data back to the construction management system.
[0016] Preferably, the central reserved hole adopts a variable cross-section design, and its diameter gradually increases from the middle of the pile body to the top of the pile body in a stepped or conical shape, and the inner wall of the hole is pre-embedded with a continuous spiral metal shear key; at least two inwardly recessed annular corrugated grooves are pre-fabricated on the outer side of the top of the pile body in the area corresponding to the rigid enlarged head, which are used to increase the mechanical interlocking force between the secondary grout and the pile body.
[0017] Preferably, the first limiting grouting uses a high-fluidity, micro-expansion modified cement-based grout, whose 28-day compressive strength design value is 60%-80% of the strength grade of the pile concrete; the grouting process adopts gravity grouting or low-pressure grouting, the grouting pressure does not exceed 0.2MPa, and a biodegradable limiting baffle or airbag is preset in the duct before grouting to accurately control the elevation of the top surface of the grouting.
[0018] Preferably, the mechanical connection is achieved through a torque-controlled connector; the connector includes a sleeve that is threaded to the top of the prestressed connecting steel bar bundle and an anchor plate that is welded or mechanically connected to the bottom plate steel bar; the connector has a preset torque monitoring point, and a digital torque wrench is used to tighten it during installation. The tightening torque value is determined by a pull-out test based on the steel bar diameter and uploaded to the quality management platform in real time.
[0019] Preferably, the second high-pressure grouting uses ultrafine cement grout or modified epoxy resin grout, and the grouting adopts a "staged pressure increase-pressure stabilization" process: the initial pressure is 0.2MPa-0.4MPa, the intermediate stabilization pressure is 0.6MPa-0.8MPa, the final stabilization pressure is not less than 1.2MPa, and after the grout absorption rate in the final stabilization stage is less than 1L / min, the pressure is held for 3-5 minutes before stopping; during the grouting process, the grout filling fullness is judged by the overflow hole or pressure sensor preset on the pile top.
[0020] Preferably, the strain monitoring is achieved by a prestressed sensor embedded in the surface of the prestressed connecting steel bar bundle or inside the rigid enlarged head; the prestressed sensor is arranged with at least three measuring points (upper, middle, and lower) along the longitudinal direction of the steel bar bundle to collect stress and strain distribution and evolution data from the flexible section to the rigid section in real time.
[0021] Preferably, the construction management system has a built-in Internet of Things (IoT) based early warning and analysis module; this module receives real-time data from the prestressing sensors and calculates the health index of the nodes based on the following formula: ;
[0022] in, This is the current measured strain value. This is the initial strain value after the base plate (10) is poured. The maximum allowable elastic strain value; when When the strain rate falls below a preset threshold or a sudden change occurs, the system automatically sends a tiered warning to the management personnel.
[0023] Preferably, it also includes a digital construction collaboration step: based on BIM technology, a three-dimensional model containing all anti-buoyancy piles and the base slab structure is established, and a unique digital identity code containing its spatial coordinates, design parameters, and construction sequence is generated for each anti-buoyancy pile; this code is made into a QR code or RFID tag and set on the corresponding pile head position on site; construction personnel can scan the tag with a mobile terminal to view the reinforcement avoidance details, connector torque requirements, and real-time records of the two grouting operations at that node in the augmented reality interface.
[0024] The construction management system also includes a calculation and analysis module for pre-construction prediction and post-construction verification; before construction, the calculation and analysis module predicts the theoretical heave deformation of the base plate under temperature changes and buoyancy based on the following formula. And it is used to guide the setting of the initial tension value of prestressed connection steel strands: ;
[0025] in, This represents the standard value of the design buoyancy force acting on a single pile. The effective length of the anti-buoyancy pile body. The elastic modulus of the concrete in the anti-buoyancy pile body, The cross-sectional area of the anti-buoyancy pile body is... The coefficient of linear expansion is 1 / 3. This represents the most unfavorable temperature difference between the construction and usage periods.
[0026] During the construction and operation phases, this module converts the strain data measured by the prestressing sensor into the actual uplift value and compares it with the theoretical uplift deformation. A comparative analysis is performed; when the deviation between the two exceeds 15%, the system determines that the boundary conditions have changed and triggers a verification command to reassess the structure's anti-buoyancy safety margin.
[0027] Compared with the prior art, the advantages of the present invention are as follows:
[0028] 1. This invention leaves a 200mm to 350mm ungrouted area at the top of the pile through the first limiting grouting, forming a flexible energy dissipation section with elastic-plastic deformation capability. The prestressed connecting steel bundles in this section can undergo slight elastic deformation, absorbing and buffering the tensile stress generated by repeated buoyancy, avoiding stress concentration at the junction of the pile top and the base plate as in traditional rigid connections, effectively preventing concrete cracking and eliminating leakage channels at the source. The second high-pressure grouting is carried out through a detachable double water-stop grouting ring or a grouting channel in the pile body. The grout fills the upper enlarged space of the pre-reserved hole at the center of the variable cross-section and the gap around the flexible section. After curing, it forms a rigid enlarged head that is tightly embedded in the base plate structure. Combined with the continuous spiral metal shear key pre-embedded in the duct and the annular corrugated groove on the outside of the pile body, the mechanical interlocking force between the secondary grout and the pile body and base plate is greatly increased, ensuring effective transmission of anti-buoyancy force.
[0029] 2. This invention collects stress and strain data in real time through prestressed sensors embedded in the rebar bundles or rigid enlarged heads. The health index is calculated by the early warning analysis module built into the construction management system, realizing real-time assessment and graded early warning of node status. The digital construction collaborative steps generate a unique code for each anti-buoyancy pile based on BIM technology. On-site scanning of QR codes or RFID tags can view detailed drawings of rebar avoidance, connector torque requirements, and grouting records. The calculation and analysis module predicts the amount of bottom plate uplift deformation through theoretical formulas and compares it with measured data. When the deviation exceeds 15%, a verification command is triggered to ensure the anti-buoyancy safety margin of the structure throughout its entire life cycle. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the construction method for the integrated connection between the anti-buoyancy pile and the base slab in the underground parking garage according to the present invention.
[0031] Figure 2 This is a cross-sectional view of the integrated connection structure between the anti-buoyancy pile and the base plate of the underground garage according to the present invention.
[0032] The numbers on the map are:
[0033] 1. Anti-buoyancy pile body; 2. Central reserved hole; 3. Connecting steel bar bundle; 4. Grouting ring; 5. Rubber waterstop strip; 6. Annular corrugated groove; 7. Grouting channel; 8. Subbase; 9. Waterproof layer; 10. Base plate; 11. Prestress sensor. Detailed Implementation
[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0035] Example
[0036] like Figure 1 and 2 As shown, this is one embodiment of the present invention, with reference to... Figure 2 As shown, the integrated connection structure of the anti-buoyancy pile and the base slab of the underground garage includes an anti-buoyancy pile body 1, a central reserved hole 2 in the middle of the anti-buoyancy pile body 1, a connecting steel bar bundle 3 pre-embedded in the central reserved hole 2, a detachable double water-stop grouting ring 4 installed on the outer side of the top of the anti-buoyancy pile body 1, a water-contact rubber water-stop strip 5 installed between the detachable double water-stop grouting ring 4 and the anti-buoyancy pile body 1, at least two inwardly recessed annular corrugated grooves 6 provided on the inner wall of the central reserved hole 2, a grouting channel 7 provided above the detachable double water-stop grouting ring 4, at least three sets of prestress sensors 11 provided inside the central reserved hole 2, a cushion layer 8 provided on the outer side of the anti-buoyancy pile body 1, a waterproof layer 9 provided above the cushion layer 8, and a base slab 10 provided above the waterproof layer 9.
[0037] Reference Figure 1 As shown, the construction method for the integrated connection between the anti-buoyancy piles and the base slab of the underground parking garage includes:
[0038] S1: A precast concrete anti-buoyancy pile body 1 with a central pre-drilled hole 2 is constructed, and a detachable double-layer water-stop grouting ring 4 is installed on the outer side of the top of the pile body. This precast process ensures the stability of the pile body quality. The central pre-drilled hole 2 provides a precise channel for the subsequent insertion of the connecting steel reinforcement bundles 3 and grouting operations. The detachable grouting ring 4 serves as temporary protection and positioning during the construction phase, and can be removed or retained as needed later without adversely affecting the permanent structure.
[0039] S2: The prestressed connecting steel bar bundle 3 is inserted into the central reserved hole 2, and the first limiting grouting is performed. The top surface of the grouting is controlled at a position 200mm to 350mm below the design elevation of the pile top, so as to form a flexible energy dissipation section with elastic-plastic deformation capability at the pile top. This design is the core difference between this invention and the traditional rigid connection. By reserving the ungrouted section, the connecting steel bar bundle 3 in this range can undergo slight elastic deformation when subjected to water buoyancy, which can absorb and buffer tensile stress, effectively preventing stress concentration and transmission to the bottom plate 10, thereby preventing concrete cracking. Controlling the grouting height to 200mm to 350mm is the optimal range verified by theoretical calculation and experiments: too low and the energy dissipation effect is insufficient; too high and it will affect the embedment depth of the rigid enlarged head.
[0040] S3: Construct the foundation layer 8 and waterproof layer 9, and seal the waterproof layer 9 to the outer wall of the grouting ring 4. Directly sealing the waterproof layer 9 to the grouting ring 4 avoids the drawbacks of traditional methods where the waterproof membrane is difficult to seal at the pile head and is easily damaged. The smooth outer wall of the grouting ring provides a reliable bonding surface for the waterproof layer. The water-swellable rubber waterstop 5 will automatically expand when groundwater seeps in later, forming a second physical waterproof barrier.
[0041] S4: Tie the reinforcing bars of the base slab 10 and mechanically connect the reinforcing bars of the base slab 10 to the top of the prestressed connecting reinforcing bar bundle 3 extending from the top of the flexible energy dissipation section. Using a mechanical connection instead of traditional lap tying ensures the continuity and reliability of the reinforcing bar stress. The connecting reinforcing bar bundle 3 is in a free state within the flexible section. After its top is connected to the reinforcing bars of the base slab 10, it can directly transfer the buoyancy force borne by the base slab 10 to the pile body, forming a complete stress chain.
[0042] S5: Erect formwork and pour concrete for the base slab 10 to form the base slab 10 structure. Use standard base slab pouring techniques, but ensure proper compaction, especially around the pile heads, to guarantee full contact between the concrete and the embedded components. At this point, the flexible energy dissipation section remains in an elasto-plastic state and has not yet formed a rigid embedment with the base slab 10. Therefore, the shrinkage deformation of the base slab 10 during the hardening process will not generate additional constraint stress on the pile body.
[0043] S6: After the initial setting of the concrete in the base slab 10, a second high-pressure grouting is performed on the pile top area through the grouting channel 7 pre-embedded in the grouting ring 4 or the pile body. The grout fills the upper enlarged space of the central reserved hole 2 and the gaps around the flexible energy dissipation section. After curing, a rigid enlarged head is formed inside the base slab 10 and is embedded in the base slab 10. This is the final step in realizing the two-stage design of "flexible connection-rigid locking". Grouting after initial setting avoids the disturbance of the grout body to the grout body caused by the plastic shrinkage of the base slab concrete, and ensures that the grout can fully fill all the small gaps under pressure. High-pressure grouting allows the grout to penetrate into the gaps of the corrugated groove and the spiral shear key. After curing, it forms an enlarged head with extremely strong mechanical interlocking force, firmly embedding the pile body and the base slab 10 together, providing the final pull-out bearing capacity.
[0044] S7: Strain monitoring is performed on the connection nodes, and the monitoring data is fed back to the construction management system. By embedding prestressed sensors 11 in key locations, the hidden works are transformed into transparent works. The monitoring data can not only be used for quality control during construction, but also serve as a basis for structural health assessment in the later operation and maintenance phase, realizing full life cycle management.
[0045] Furthermore, the central reserved hole 2 adopts a variable cross-section design, with its diameter gradually increasing from the middle of the pile body towards the top of the pile in a stepped or conical shape, and a continuous spiral metal shear key is pre-embedded in the inner wall of the duct; at least two inwardly recessed annular corrugated grooves 6 are prefabricated on the outer side of the top of the pile body in the area corresponding to the rigid enlarged head, which are used to increase the mechanical interlocking force between the secondary grout and the pile body. The combination design of variable cross-section and shear key makes the secondary grout form an inverted wedge-shaped structure with "small outside and large inside" in the duct. With the embedding of the spiral shear key, the pull-out bearing capacity of the grout and the pile body is greatly enhanced.
[0046] Furthermore, the first limiting grouting uses a high-fluidity, micro-expansion modified cement-based grout, whose 28-day compressive strength design value is 60%-80% of the pile concrete strength grade. The grouting process adopts gravity or low-pressure grouting, with a grouting pressure not exceeding 0.2MPa. Before grouting, a biodegradable limiting baffle or airbag is preset in the duct to accurately control the grouting top elevation. The grout strength is selected to be slightly lower than the pile strength to ensure that the flexible energy dissipation section can preferentially undergo controllable deformation under stress, thus protecting the pile body and the base plate. The use of limiting baffles or airbags solves the problem of accurately controlling the liquid level height in traditional grouting, ensuring that the flexible section length of each pile is consistent and the stress performance is uniform.
[0047] Specifically, the mechanical connection is achieved through a torque-controlled connector. The connector includes a sleeve that threads with the top of the prestressed steel bar bundle 3 and an anchor plate that is welded or mechanically connected to the bottom slab reinforcement 10. The connector has pre-set torque monitoring points. During installation, a digital torque wrench is used for tightening. The tightening torque value is determined based on the steel bar diameter through a pull-out test and uploaded to the quality management platform in real time. The torque-controlled connector transforms the traditional "tightening based on experience" into "data-driven precise control." The torque value of each connector is uploaded in real time, forming a traceable quality record and avoiding inconsistent connection quality caused by human error. The anchor plate design disperses the concentrated tensile force of the steel bar bundle, ensuring it is evenly distributed to the bottom slab reinforcement.
[0048] Specifically, the second high-pressure grouting uses ultrafine cement grout or modified epoxy resin grout, employing a "staged pressure increase-stabilization" process: the initial pressure is 0.2MPa-0.4MPa, the intermediate stabilization pressure is 0.6MPa-0.8MPa, and the final stabilization pressure is not less than 1.2MPa. After the grout absorption rate in the final stabilization stage is less than 1L / min, the pressure is maintained for 3-5 minutes before stopping. During grouting, the grout filling fullness is judged by overflow holes pre-installed at the pile top or by pressure sensors. The staged pressure increase process avoids the impact of instantaneous high pressure on the initial set concrete of the foundation slab, while ensuring that the grout can gradually penetrate into the small gaps. Controlling the grout absorption rate during the stabilization stage is a key indicator for judging the filling density. When the grout absorption rate drops to an extremely low level and the pressure stabilizes, it indicates that all voids have been fully filled, and the quality of the rigid enlarged head is guaranteed.
[0049] Specifically, strain monitoring is achieved through prestressed sensors 11 embedded in the surface of the prestressed connecting steel strands or inside the rigid enlarged head. At least three measuring points (upper, middle, and lower) are arranged along the longitudinal direction of the connecting steel strands to collect real-time data on the stress and strain distribution and evolution from the flexible section to the rigid section. The arrangement of these three measuring points allows for a comprehensive understanding of the stress conditions in the transition area from the flexible energy dissipation section to the rigid enlarged head. When abnormal stress changes occur at a certain location, the system can promptly detect and locate the problem, providing accurate information for subsequent reinforcement or maintenance.
[0050] The construction management system has a built-in IoT-based early warning and analysis module; this module receives real-time data from the prestressing sensor 11 and calculates the health index of the nodes based on the following formula: ;
[0051] in, This is the current measured strain value. This is the initial strain value after the base plate (10) is poured. The maximum allowable elastic strain value; when When the strain rate falls below a preset threshold or a sudden change occurs, the system automatically sends a tiered warning to the management personnel.
[0052] The introduction of the Health Index transforms abstract stress data into intuitive health status indicators. Managers can quickly determine whether a node is in a safe state using the HI value without needing specialized structural analysis knowledge. A tiered early warning mechanism (such as yellow, orange, and red alerts) provides a basis for taking different levels of response measures, avoiding overreactions like "shutting down at the slightest fluctuation" and preventing the potential for "small problems to escalate into major accidents."
[0053] Furthermore, a digital construction collaboration step is included: A 3D model containing all anti-buoyancy piles and the base slab structure is created based on BIM technology, and a unique digital identification code is generated for each anti-buoyancy pile, containing its spatial coordinates, design parameters, and construction sequence. This code is then made into a QR code or RFID tag and placed on-site at the corresponding pile head location. Construction personnel can scan the tag with a mobile terminal to view detailed rebar avoidance drawings, connector torque requirements, and real-time records of two grouting operations in an augmented reality interface. Digital collaboration upgrades the traditional "drawing-based construction" to "model-based construction." On-site personnel can obtain the unique construction information for each pile simply by scanning, avoiding errors in drawing interpretation or information transmission distortion. The augmented reality interface can overlay the 3D model onto the actual structure, intuitively displaying the rebar direction and connection positions, which is particularly suitable for precise construction of complex joints.
[0054] The construction management system also includes a calculation and analysis module for pre-construction prediction and post-construction verification; before construction, the calculation and analysis module predicts the theoretical heave deformation of the base plate under temperature changes and water buoyancy based on the following formula. And used to guide the setting of the initial tension value of the prestressed connection steel bar bundle (3):
[0055] ;
[0056] in, This represents the standard value of the design buoyancy force acting on a single pile. The effective length of the anti-buoyancy pile body. The elastic modulus of the concrete in the anti-buoyancy pile body, The cross-sectional area of the anti-buoyancy pile body is... The coefficient of linear expansion is 1 / 3. This represents the most unfavorable temperature difference between the construction and usage periods.
[0057] During the construction and operation phases, this module converts the strain data measured by the prestressed sensor (11) into the actual uplift value and compares it with the theoretical uplift deformation. A comparative analysis is performed; when the deviation between the two exceeds 15%, the system determines that the boundary conditions have changed and triggers a verification command to reassess the structure's anti-buoyancy safety margin.
[0058] Before construction, deformation is predicted through theoretical calculations to guide the setting of prestressing tension values. During the operation phase, the accuracy of the theoretical model is verified through measured data. If deviations exceed a reasonable range, a review process is initiated promptly to reassess structural safety. The 15% deviation threshold is set based on empirical values from a large amount of engineering statistical data: deviations less than 15% can be considered normal fluctuations, while deviations exceeding 15% indicate a significant difference between actual working conditions and design assumptions, requiring attention.
[0059] Working principle: First, a flexible energy dissipation section is reserved at the top of the pile to absorb and buffer the tensile stress under repeated buoyancy, avoiding concrete cracking caused by stress concentration. After the bottom slab concrete hardens, a second high-pressure grouting is used to form a rigid enlarged head, which is tightly embedded with the pile body and bottom slab, providing the final pull-out bearing capacity. The detachable double water-stop grouting ring and variable cross-section duct design solve the two major problems of joint waterproofing and stress transfer. A digital monitoring and management system runs through the entire process, from pre-prediction and in-process control to post-evaluation, forming a complete quality assurance closed loop, significantly improving the reliability and construction efficiency of the underground parking garage anti-buoyancy system.
Claims
1. An integrated connection structure between anti-buoyancy piles and the base slab of an underground parking garage, characterized in that, include: The anti-buoyancy pile body (1) has a central reserved hole (2) in the middle of the anti-buoyancy pile body (1), and a connecting steel bar bundle (3) is pre-embedded inside the central reserved hole (2). A grouting ring (4) is installed on the outer side of the top of the anti-buoyancy pile body (1), and a rubber waterstop strip (5) is installed between the grouting ring (4) and the anti-buoyancy pile body (1). Annular corrugated grooves (6) are opened on the inner wall of the central reserved hole (2), and at least two grooves are opened and are recessed radially toward the anti-buoyancy pile body (1); The grouting channel (7) extends into the grouting ring (4) at the bottom and is connected to the central reserved hole (2); At least three sets of prestressed sensors (11) are installed inside the central reserved hole (2). A cushion layer (8) is installed on the outside of the anti-buoyancy pile body (1). A waterproof layer (9) is installed above the cushion layer (8). A base plate (10) is installed above the waterproof layer (9).
2. A construction method for an integrated connection structure between anti-buoyancy piles and the base slab of an underground parking garage, comprising the integrated connection structure of anti-buoyancy piles and the base slab of claim 1, characterized in that, It also includes the following steps: S1: The precast concrete anti-buoyancy pile body (1) with a central reserved hole (2) is integrally cast with an annular corrugated groove (6); First, install a rubber waterstop strip (5) on the outer side of the top of the anti-buoyancy pile body (1), and then install a grouting ring (4). S2: Insert the connecting steel bar bundle (3) into the central reserved hole (2) and check the alignment; Multiple sets of prestressed sensors (11) are installed in the central reserved hole (2) at different heights; Then, the first limiting grouting is carried out. The top surface of the grouting is controlled at a position 200-350mm lower than the design elevation of the top of the anti-buoyancy pile body (1) to form a flexible energy dissipation section. S3: Construction cushion layer (8) and waterproof layer (9): First, lay the construction cushion layer (8) around the outside of the anti-buoyancy pile body (1); then, surround the waterproof layer (9) on the outer wall of the grouting ring (4) and seal it; the waterproof layer (9) is located on top of the construction cushion layer (8); S4: Tie the reinforcing bars used for casting the base slab (10) and connect the reinforcing bars to the top of the connecting reinforcing bar bundle (3) extending from the top of the flexible energy dissipation section; S5: Erect formwork and pour concrete to form the base plate (10), thus forming the base plate (10) structure; S6: After the concrete of the base plate (10) has initially set, the second high-pressure grouting is carried out in the pile top area of the anti-buoyancy pile through the grouting channel (7) embedded in the grouting ring (4) or the pile body. The grout fills the upper enlarged space of the central reserved hole (2) and the gap around the flexible energy dissipation section. After solidification, a rigid enlarged head is formed inside the base plate (10) and embedded in the base plate (10). S7: Perform strain monitoring on the connection structure and feed the monitoring data back to the construction management system.
3. The construction method of the underground garage anti-floating pile and bottom plate integrated connection structure according to claim 2, characterized in that: The central reserved hole (2) adopts a variable cross-section design, and the depth of the central reserved hole (2) extends to the middle of the anti-buoyancy pile body (1); the diameter of the central reserved hole (2) gradually increases from the bottom to the top of the pile in a stepped or conical shape; at least two inwardly recessed annular corrugated grooves (6) are prefabricated in the central reserved hole (2).
4. The construction method of the underground garage anti-floating pile and bottom plate integrated connection structure according to claim 2, characterized in that: The first limiting grouting uses a high-fluidity, micro-expansion modified cement-based grout, so that the design value of the 28-day compressive strength is 60%~80% of the concrete strength grade of the anti-buoyancy pile body (1); During the grouting process, gravity grouting or low-pressure grouting is used, and the grouting pressure does not exceed 0.2 MPa; Before grouting, a biodegradable limiting baffle or airbag is pre-installed in the central reserved hole (2) to precisely control the elevation of the top surface of the grouting.
5. The construction method of the underground garage anti-floating pile and bottom plate integrated connection structure according to claim 2, characterized in that: The second high-pressure grouting uses ultrafine cement grout or modified epoxy resin grout, and the grouting adopts a graded process: The initial pressure is 0.2MPa-0.4MPa, the intermediate stabilizing pressure is 0.6MPa-0.8MPa, and the final stabilizing pressure is not less than 1.2MPa; After the grout absorption rate is less than 1L / min in the final pressure stabilization stage, stop grouting after holding the pressure for 3-5 minutes.
6. The construction method of the underground garage anti-floating pile and bottom plate integrated connection structure according to claim 2, characterized in that: For strain monitoring in step S7, it is monitored by prestressing sensor (11) embedded in the surface of prestressed connecting steel bar bundle (3) or in the central reserved hole (2); The prestressed sensor (11) is arranged with at least three measuring points (upper, middle, and lower) along the axial direction of the connecting steel bar bundle (3) to collect strain distribution and evolution data after grouting in real time.
7. The construction method of the underground garage anti-floating pile and bottom plate integrated connection structure according to claim 6, characterized in that: An IoT-based early warning analysis module is built into the construction management system; the early warning analysis module is used to receive real-time data from the prestressed sensor (11) and calculate the health index of the connection structure based on the following formula: ； in, This is the current measured strain value. This is the initial strain value after the base plate (10) is poured. The maximum allowable elastic strain value; when When the strain rate falls below a preset threshold or a sudden change occurs, the system automatically sends a tiered warning to the management personnel.
8. The construction method for the integrated connection structure of anti-buoyancy piles and base slab in underground parking garages according to claim 2, characterized in that: It also includes a digital construction collaboration step: based on BIM technology, a three-dimensional model containing all anti-buoyancy piles and the base plate (10) structure is established, and a unique digital identity code containing its spatial coordinates, design parameters and construction sequence is generated for each anti-buoyancy pile; the code is made into a QR code or RFID tag and set on the site at the corresponding visible position of the pile head; the construction personnel can scan the tag with a mobile terminal to view the steel reinforcement avoidance details of the connection structure and the real-time record of the two grouting in the augmented reality interface.
9. The construction method of the integrated connection structure between the anti-buoyancy pile and the base slab of the underground garage according to claim 8, characterized in that: The construction management system also includes a calculation and analysis module for pre-construction prediction and post-construction verification; before construction, the calculation and analysis module predicts the theoretical heave deformation of the bottom plate (10) under temperature change and water buoyancy based on the following formula. And used to guide the setting of the initial tension value of the prestressed connection steel bar bundle (3): ； in, This represents the standard value of the design buoyancy force acting on a single pile. The effective length of the anti-buoyancy pile body. The elastic modulus of the concrete in the anti-buoyancy pile body, The cross-sectional area of the anti-buoyancy pile body is... The coefficient of linear expansion is 1 / 3. This represents the most unfavorable temperature difference between the construction and usage periods. During the construction and operation phases, this module converts the strain data measured by the prestressed sensor (11) into the actual uplift value and compares it with the theoretical uplift deformation. A comparative analysis is performed; when the deviation between the two exceeds 15%, the system determines that the boundary conditions have changed and triggers a verification command to reassess the structure's anti-buoyancy safety margin.