Longitudinal tensioning method for prefabricated top plate of assembly type entrance and exit

Abstract

The invention discloses a longitudinal tensioning method for a prefabricated top plate of an assembly type entrance and exit. The longitudinal tensioning method comprises the following steps that a counter-force anchor bed is pre-buried in a cast-in-place inverted-T-shaped beam at the corner position of the entrance and exit; mounting a prefabricated top plate connected with the main body section; the prefabricated top plate of the butt joint main body section is tensioned; a cast-in-place wet joint is constructed at the position of a corner straight section; hoisting the prefabricated top plate of the straight section; the prefabricated top plate of the straight section is tensioned; the tail block prefabricated top plate of the straight section serves as the first prefabricated top plate of the climbing section; hoisting a prefabricated top plate of a climbing section; and the prefabricated top plate of the climbing section is tensioned. The method is easy to operate, the timeliness in the construction process can be guaranteed, and the problem that the construction speed is low in a traditional cast-in-place process is solved; the connection and waterproof capability between the block prefabricated top plates is enhanced, and the later-period water leakage problem can be effectively avoided. Construction errors in the installation process of the prefabricated top plate can be effectively solved through partitioned tensioning, and the errors are adjusted according to the cast-in-place position in the later period.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground structure engineering, and particularly relates to a longitudinal tensioning method for precast roof slabs of prefabricated entrances and exits. Background Art

[0002] The longitudinal tensioning method for precast roof slabs of prefabricated entrances and exits is mainly applied in modern building construction, especially in engineering projects such as subway stations and underground passages that require rapid construction and quality assurance. The core of this method lies in assembling prefabricated roof slab components on site and using longitudinal tensioning technology to enhance the overall stability and bearing capacity of the structure.

[0003] The present invention provides a longitudinal tensioning method for precast roof slabs of prefabricated entrances and exits. In the actual application process, the longitudinal tensioning technology for precast roof slabs of prefabricated entrances and exits can significantly improve construction efficiency and reduce the time and labor costs required for on-site concrete pouring. At the same time, since the prefabricated components are produced in the factory, it is possible to better control product quality and ensure that each component meets the design standards. In addition, this method is also beneficial to environmental protection, reducing noise pollution and dust emissions at the construction site.

[0004] With the acceleration of the urbanization process and the continuous improvement of requirements for building quality and construction efficiency, the longitudinal tensioning technology for precast roof slabs of prefabricated entrances and exits, as an efficient and environmentally friendly construction method, will be more widely applied and developed in the future. Summary of the Invention

[0005] The present invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a longitudinal tensioning method for precast roof slabs of prefabricated entrances and exits.

[0006] The technical solution of the present invention is: a longitudinal tensioning method for precast roof slabs of prefabricated entrances and exits, including the following steps: A. Embedding reaction force anchor seats in the cast-in-place inverted T-shaped beams at the corner positions of the entrance and exit; B. Installing the precast roof slabs of the main body connection section; C. Tensioning the precast roof slabs of the main body connection section; D. Constructing a cast-in-place wet joint at the straight section of the corner; E. Hoisting the precast roof slabs of the straight section; F. Tensioning the precast roof slabs of the straight section; G. Using the end block precast roof slab of the straight section as the first precast roof slab of the climbing section; H. Hoisting the precast roof slabs of the climbing section; I. Tensioning the precast roof slabs of the climbing section.

[0007] Furthermore, in step A, reaction force anchor seats are embedded in the cast-in-place inverted T-beam at the entrance and exit corner position, and the specific process is as follows: First, embed reaction force anchor seats in the cast-in-place inverted T-beam at the entrance and exit corner position; Then, use the above reaction force anchor seats as the tensioning foundation for the precast top slab of the connecting main body section; Finally, after the strength of the cast-in-place inverted T-beam and the reaction force anchor seats reaches the design requirements, carry out subsequent construction.

[0008] Furthermore, in step B, install the precast top slab of the connecting main body section, and the specific process is as follows: First, hoist the first precast top slab of the connecting main body section; Then, after the first precast top slab reaches the predetermined position, pass the fine-threaded deformed steel bars through the reserved holes for fine-threaded deformed steel bars; Finally, connect the passed fine-threaded deformed steel bars to the reaction force anchor seats through connectors.

[0009] Furthermore, in step C, tension the precast top slab of the connecting main body section, and the specific process is as follows: First, carry out prestress tensioning through the fine-threaded deformed steel bars and the reaction force anchor seats; Then, after the axial force reaches the design value, hold the load for a period of time and lock it with nuts; Finally, repeat steps B and C to complete the installation and tensioning of the precast top slab of the connecting main body section.

[0010] Furthermore, in step D, construct a cast-in-place wet joint at the straight section of the corner, and the specific process is as follows: First, determine the position of the first precast top slab of the straight section; Then, construct the cast-in-place wet joint; Finally, reserve reaction force anchor seats for the straight section in the cast-in-place wet joint.

[0011] Furthermore, in step E, hoist the precast top slab of the straight section, and the specific process is as follows: First, after the strength of the cast-in-place wet joint and the reaction force anchor seats for the straight section reaches the design requirements, start hoisting the first precast top slab of the straight section; Next, after the first precast top slab reaches the predetermined position, pass the fine-threaded deformed steel bars through the reserved holes for fine-threaded deformed steel bars; Finally, connect the passed fine-threaded deformed steel bars to the reaction force anchor seats for the straight section through connectors.

[0012] Furthermore, in step F, tension the precast top slab of the straight section, and the specific process is as follows: First, carry out prestress tensioning through the fine-threaded deformed steel bars and the reaction force anchor seats for the straight section; Then, after the axial force reaches the design value, hold the load for a period of time and lock it with nuts; Finally, repeat Step E and Step F to complete the installation and tensioning of the precast roof slab for the straight section.

[0013] Furthermore, in Step G, the tail precast roof slab of the straight section is used as the first precast roof slab of the ramp section, and the specific process is as follows: First, after the sequential construction of the precast roof slab of the straight section, enter the ramp section; Then, use the tail precast roof slab that has entered the ramp section as the first precast roof slab of the ramp section; Finally, use the above precast roof slab as the reaction frame for the tensioning of the ramp section.

[0014] Furthermore, in Step H, hoist the precast roof slab of the ramp section, and the specific process is as follows: First, hoist the first precast roof slab of the ramp section; After that, after the first precast roof slab reaches the predetermined position, pass the high-strength steel bar through the reserved hole of the high-strength steel bar; Finally, connect the passed high-strength steel bar to the reaction frame in the tail precast roof slab of the straight section through a connector.

[0015] Furthermore, in Step I, tension the precast roof slab of the ramp section, and the specific process is as follows: First, conduct prestress tensioning through the high-strength steel bar; Then, after the axial force reaches the design value, hold the load for a period of time and lock it with a nut; Finally, repeat Step H and Step I to complete the installation and tensioning of the precast roof slab for the connected ramp section.

[0016] The beneficial effects of the present invention are as follows: The present invention improves the structural stability: Through longitudinal tensioning, the overall stiffness of the precast roof slab can be increased, and the deformation caused by factors such as temperature changes and load effects can be reduced.

[0017] The present invention reduces cracks: Tensioning can effectively reduce the cracks caused by concrete shrinkage, temperature changes, and stress, thereby improving the durability of the structure.

[0018] The present invention improves the seismic performance of the structure: Tensioning can enhance the seismic performance of the structure, making it have better energy absorption performance in the face of natural disasters such as earthquakes.

[0019] The present invention enhances the structural stability: The application of the longitudinal tensioning technology makes the roof slab structure more stable and improves the safety performance of the overall structure. This is particularly important for important facilities such as underground entrances and exits.

[0020] The present invention has strong adaptability: This method can flexibly adjust the design of precast components and tensioning schemes according to different engineering requirements, and is applicable to construction projects in a variety of complex environments. Brief Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the reserved ducts on the precast top slab in the present invention; Figure 2 It is a schematic diagram of the reserved ducts on the precast top slab and the inserted high-strength threaded steel bars in the present invention; Figure 3 It is a schematic diagram of the tensioning area of the top slab of the connection main body section in the present invention; Figure 4 It is a detailed drawing of the tensioning of the top slab of the connection main body section in the present invention; Figure 5 It is a schematic diagram of the tensioning area of the straight section of the corner section in the present invention; Figure 6 It is a detailed drawing of the tensioning of the tensioning area of the straight section of the corner section in the present invention; Figure 7 It is a schematic diagram of the tensioning of the tensioning area of the climbing section in the present invention; Figure 8 It is a detailed drawing of the tensioning of the tensioning area of the climbing section in the present invention. Detailed Description of the Preferred Embodiment

[0022] Hereinafter, the present invention will be described in detail with reference to the drawings and embodiments: As Figures 1 to 8 shown, a longitudinal tensioning method for the precast top slab of an assembled entrance and exit includes the following steps: A. Embedding a reaction anchor seat in the cast-in-place inverted T-shaped beam at the corner position of the entrance and exit; B. Installing the precast top slab of the connection main body section; C. Tensioning the precast top slab of the connection main body section; D. Constructing a cast-in-place wet joint at the straight section of the corner; E. Hoisting the precast top slab of the straight section; F. Tensioning the precast top slab of the straight section; G. Using the tail block precast top slab of the straight section as the first precast top slab of the climbing section; H. Hoisting the precast top slab of the climbing section; I. Tensioning the precast top slab of the climbing section.

[0023] The process of step A for embedding the reaction anchor seat in the cast-in-place inverted T-shaped beam at the corner position of the entrance and exit is as follows: First, embed the reaction anchor seat in the cast-in-place inverted T-shaped beam at the corner position of the entrance and exit; Then, use the above reaction anchor seat as the tensioning foundation for the precast top slab of the connection main body section; Finally, after the strength of the cast-in-place inverted T-shaped beam and the reaction anchor seat reaches the design requirements, carry out subsequent construction.

[0024] Step B: Install the precast roof slab connecting to the main body section. The specific process is as follows: First, hoist the first precast roof slab connecting to the main body section; After that, when the first precast roof slab reaches the predetermined position, pass the high-strength threaded steel through the reserved holes of the high-strength threaded steel; Finally, connect the passed high-strength threaded steel to the reaction anchor block through a connector.

[0025] Step C: Tension the precast roof slab connecting to the main body section. The specific process is as follows: First, conduct prestress tensioning through the high-strength threaded steel and the reaction anchor block; Then, after the axial force reaches the design value, hold the load for a period of time and lock it with nuts; Finally, repeat Step B and Step C to complete the installation and tensioning of the precast roof slab connecting to the main body section.

[0026] Step D: Construct the cast-in-place wet joint at the corner straight section. The specific process is as follows: First, determine the position of the first precast roof slab in the straight section; Then, construct the cast-in-place wet joint; Finally, reserve the reaction anchor block for the straight section in the cast-in-place wet joint.

[0027] Step E: Hoist the precast roof slab of the straight section. The specific process is as follows: First, after the strength of the cast-in-place wet joint and the reaction anchor block of the straight section reaches the design requirements, start hoisting the first precast roof slab of the straight section; Then, when the first precast roof slab reaches the predetermined position, pass the high-strength threaded steel through the reserved holes of the high-strength threaded steel; Finally, connect the passed high-strength threaded steel to the reaction anchor block of the straight section through a connector.

[0028] Step F: Tension the precast roof slab of the straight section. The specific process is as follows: First, conduct prestress tensioning through the high-strength threaded steel and the reaction anchor block of the straight section; Then, after the axial force reaches the design value, hold the load for a period of time and lock it with nuts; Finally, repeat Step E and Step F to complete the installation and tensioning of the precast roof slab of the straight section.

[0029] Step G: Use the tail precast roof slab of the straight section as the first precast roof slab of the climbing section. The specific process is as follows: First, after the sequential construction of the precast roof slabs of the straight section, enter the climbing section; Then, use the tail precast roof slab that has entered the running slope section as the first precast roof slab of the climbing section; Finally, use the above-mentioned precast roof slab as the reaction frame for tensioning in the climbing section.

[0030] Step H: Hoist the precast roof slab of the climbing section. The specific process is as follows: First, hoist the first precast roof slab of the climbing section; After that, after the first precast roof slab reaches the predetermined position, pass the high-strength steel bar through the reserved hole of the high-strength steel bar; Finally, connect the passed high-strength steel bar to the reaction frame in the tail precast roof slab of the straight section through a connector.

[0031] Step I: Tension the precast roof slab of the climbing section. The specific process is as follows: First, perform prestress tensioning through the high-strength steel bar; Then, after the axial force reaches the design value, hold the load for a period of time and lock it with a nut; Finally, repeat Step H and Step I to complete the installation and tensioning of the precast roof slab of the connecting climbing section.

[0032] Specifically, the present invention divides the tensioning operation into zones, including the connecting main body section, the straight section, and the climbing section, and performs zone tensioning on the connecting main body section, the straight section, and the climbing section.

[0033] Specifically, within each precast roof slab area, adopt the tensioning method of each precast roof slab to perform tensioning one by one.

[0034] Specifically, two Φ60 reserved holes for high-strength steel bars are longitudinally reserved in the above-mentioned precast roof slab. The reserved holes for high-strength steel bars are used to pass through the high-strength steel bars, and the two reserved holes for high-strength steel bars are evenly distributed in the precast roof slab.

[0035] Specifically, during the zone tensioning process, embed reaction force anchor seats in the cast-in-place inverted T-shaped beam at the entrance and exit corner positions. After the reaction force anchor seats are stable and can bear the load, the tensioning of the roof slab in the standard section area at the connecting station main body position can be carried out. After the tensioning of the standard section area at the connecting station main body position is completed, the tensioning of the roof slab in the standard section after the corner section is carried out, and finally the tensioning of the precast roof slab in the climbing section is carried out.

[0036] Specifically, during the process of tensioning one by one, hoist the first precast roof slab in the expected tensioning area to the designated position, then pass the high-strength steel bar through the two reserved holes for high-strength steel bars on the precast roof slab, connect it firmly with the reaction frame, apply prestress, hold the load for a period of time, and then tighten and fix it with the supporting nut. After the above steps are completed, hoist the next precast roof slab to the designated position in sequence, continue to pass the high-strength steel bar through the reserved hole for high-strength steel bar, connect it with the connector in the previous diaphragm wall, apply prestress, hold the load for a period of time, and then tighten and fix it with the supporting nut until all precast roof slabs are installed.

[0037] Specifically, as Figure 1 、 Figure 2As shown, an exhaust hole is also provided at the reserved hole of the precision rolled ribbed steel, which is vertically connected thereto for exhausting during the grouting process.

[0038] Specifically, a reserved hand hole is formed on one side of the precast roof slab for accommodating the connector and the anchor head through the reserved hand hole.

[0039] More specifically, a grouting hole is provided in the reserved hand hole and is communicated therewith, and grouting is carried out into the reserved hand hole after tensioning through the grouting hole.

[0040] Specifically, as Figure 3 、 Figure 4 shown, it is the installation and tensioning diagram of the connecting main body section. The cast-in-place inverted T-beam is located at the corner of the entrance and exit, and the tensioning direction of the precast roof slab of the connecting main body section is from the cast-in-place inverted T-beam to the cast-in-place roof slab direction.

[0041] Specifically, as Figure 5 、 Figure 6 shown, it is the installation and tensioning diagram of the straight section. The cast-in-place wet joint is located at one end of the straight section, and a reaction anchor seat for the straight section is embedded in the cast-in-place wet joint, and the tensioning direction is from the cast-in-place wet joint to the climbing section.

[0042] Specifically, as Figure 7 、 Figure 8 shown, it is the installation and tensioning diagram of the climbing section. The precast roof slab at the tail end of the straight section is used as a reaction frame, and the tensioning direction is away from the straight section direction.

[0043] The present invention improves the structural stability: through longitudinal tensioning, the overall stiffness of the precast roof slab can be increased, and the deformation caused by factors such as temperature change and load action can be reduced.

[0044] The present invention reduces cracks: Tensioning can effectively reduce the cracks caused by concrete shrinkage, temperature change and stress, thereby improving the durability of the structure.

[0045] The present invention improves the seismic performance of the structure: Tensioning can enhance the seismic performance of the structure, making it have better energy absorption performance in the face of natural disasters such as earthquakes.

[0046] The present invention enhances the structural stability: The application of the longitudinal tensioning technology makes the roof slab structure more stable and improves the safety performance of the overall structure. This is particularly important for important facilities such as underground entrances and exits.

[0047] The present invention has strong adaptability: This method can flexibly adjust the design of precast components and tensioning schemes according to different engineering requirements, and is applicable to construction projects in a variety of complex environments.

Claims

1. A method for longitudinal tensioning of a prefabricated roof of an assembled entrance and exit, characterized in that: The following steps are involved: A. Pre-embed the reaction force anchor in the cast-in-place inverted T-beam at the entrance and exit corner; B. Install the prefabricated top plate connected to the main body section; C. Tensioning the prefabricated top plate of the main section; D. Cast-in-place wet joints are constructed at the straight section of the corner; E. Hoisting of the straight section of prefabricated top plate; F. Tension the prefabricated top plate of the straight section; G. Use the tail prefabricated top plate of the straight section as the first prefabricated top plate of the climbing section; H. Hoisting the prefabricated top plate of the climbing section; I. Tension the prefabricated top plate of the climbing section.

2. A method for longitudinally tensioning a prefabricated roof of an assembled entrance and exit according to claim 1, characterized in that: Step A: embed the reaction force anchor in the cast-in-place inverted T-beam at the entrance and exit corner. The specific process is as follows: First, embed the reaction force anchor in the cast-in-place inverted T-beam at the entrance and exit corners; Then, the reaction anchor seat is used as a tensioning foundation for the prefabricated top plate of the main body section; Finally, after the strength of the cast-in-place inverted T-beam and reaction anchor seat reaches the design requirements, subsequent construction will be carried out.

3. A longitudinal tensioning method for a prefabricated roof of an assembled entrance and exit according to claim 1, characterized in that: Step B installs the prefabricated top plate of the main body section. The specific process is as follows: First, the first prefabricated top plate of the main section is hoisted and installed; Then, after the first prefabricated top plate reaches the predetermined position, the fine-rolled threaded steel bar is inserted through the reserved hole of the fine-rolled threaded steel bar; Finally, the inserted fine-rolled threaded steel bar is connected to the reaction anchor seat through a connector.

4. A method for longitudinally tensioning a prefabricated roof of an assembled entrance and exit according to claim 1, characterized in that: Step C: tensioning the prefabricated top plate of the main section. The specific process is as follows: First, prestressing is performed through precision-rolled threaded steel bars and reaction anchors; Then, after the axial force reaches the design value, the load is maintained for a period of time and the nut is used for locking; Finally, repeat steps B and C to complete the installation and tensioning of the prefabricated top plate of the main body section.

5. The longitudinal tensioning method of a prefabricated roof plate of an assembled entrance and exit according to claim 1, characterized in that: Step D: Cast-in-place wet joints are constructed at the straight section of the corner. The specific process is as follows: First, determine the position of the first prefabricated top plate of the straight section; Then, the cast-in-place wet joint is constructed; Finally, reserve a straight section reaction anchor seat in the cast-in-place wet joint.

6. A method for longitudinally tensioning a prefabricated roof of an assembled entrance and exit according to claim 1, characterized in that: Step E: hoist the prefabricated top plate of the straight section. The specific process is as follows: First, after the strength of the cast-in-place wet joint and the straight section reaction anchor seat reaches the design requirements, the first prefabricated top plate of the straight section is hoisted; Then, after the first prefabricated top plate reaches the predetermined position, the fine-rolled threaded steel bar is inserted through the reserved hole of the fine-rolled threaded steel bar; Finally, the inserted fine-rolled threaded steel bar is connected to the straight section reaction anchor seat through a connector.

7. A method for longitudinally tensioning a prefabricated roof of an assembled entrance and exit according to claim 1, characterized in that: Step F is to tension the prefabricated top plate of the straight section, and the specific process is as follows: First, prestressing is performed through the precision-rolled threaded steel bars and the straight section reaction anchor seats; Then, after the axial force reaches the design value, the load is maintained for a period of time and the nut is used for locking; Finally, repeat steps E and F to complete the installation and tensioning of the prefabricated top plate of the straight section.

8. The longitudinal tensioning method of a prefabricated roof plate of an assembled entrance and exit according to claim 1, characterized in that: Step G uses the tail prefabricated top plate of the straight section as the first prefabricated top plate of the climbing section. The specific process is as follows: First, after sequentially constructing the prefabricated top slab of the straight section, enter the climbing section; Then, the tail prefabricated top plate that has entered the running slope section is used as the first prefabricated top plate of the climbing section; Finally, the prefabricated top plate is used as a reaction frame for tensioning the climbing section.

9. A method for longitudinally tensioning a prefabricated roof of an assembled entrance and exit according to claim 1, characterized in that: Step H: hoisting the prefabricated top plate of the climbing section. The specific process is as follows: First, the first prefabricated top plate of the climbing section was hoisted; Then, after the first prefabricated top plate reaches the predetermined position, the fine-rolled threaded steel bar is inserted through the reserved hole of the fine-rolled threaded steel bar; Finally, the inserted fine-rolled threaded steel bar is connected to the reaction frame in the prefabricated top plate of the tail block of the straight section through a connector.

10. A longitudinal tensioning method for a prefabricated roof of an assembled entrance and exit according to claim 1, characterized in that: Step I is to tension the prefabricated top plate of the climbing section, and the specific process is as follows: First, prestressing is performed by fine-rolling rebar; Then, after the axial force reaches the design value, the load is maintained for a period of time and the nut is used for locking; Finally, repeat steps H and I to complete the installation and tensioning of the prefabricated top plate of the climbing section.

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