Embedded construction method for underground engineering post-connection channel steel bar connector

Abstract

The invention relates to the technical field of underground engineering structure construction, in particular to an underground engineering post-connection channel steel bar connector pre-embedding construction method which comprises the steps that in the underground engineering outer wall construction stage, outer wall embedded columns are arranged at the preset positions of a post-connection channel; u-shaped anchoring steel bars are arranged, and steel bar connectors are fixed to the ends of the U-shaped anchoring steel bars; an isolation plate is arranged between the embedded column and the foundation pit supporting structure, and the end of the connector is embedded into the isolation plate; outer wall horizontal steel bars are bent to bypass the isolation plates and then anchored to the embedded columns, and then concrete is poured to complete main body forming; in the post-connection channel construction stage, a corresponding foundation pit supporting structure is chiseled away, an isolation plate is dismantled, a connector is cleaned, and post-connection channel outer wall steel bars are in butt joint with the connector; and constructing the communication channel reinforced concrete outer wall to form an integral structure. Precise pre-burying of the connector is achieved in the early stage, the connector is prevented from being covered by concrete, the complete connector can be exposed by directly dismantling the isolation plate in the later stage, the survival rate of the connector is greatly increased, additional steel bar planting is not needed, and the construction cost and the construction period are reduced.

Description

Technical Field

[0001] This invention relates to the field of underground engineering structure construction technology, and in particular to a method for pre-embedding steel reinforcement connectors for underground engineering post-connection channels. Background Technology

[0002] In the construction of underground projects such as urban subways, integrated utility tunnels, and underground parking garages, due to the influence of the construction site, surrounding environment, and phased construction planning, it is often necessary to connect the passage structure to the outer wall of the completed underground project. In addition, many projects have the construction conditions where the foundation pit support structure is close to the outer wall of the underground project. Under such conditions, the steel reinforcement connection construction of the connecting passage is a key process to ensure the overall structural stability of the underground project.

[0003] Currently, the conventional practice for the construction of subsequent access channels in situations where the foundation pit support structure is in close proximity to the exterior wall of the underground project is to install concealed columns at the corresponding locations of the subsequent access channels within the exterior wall of the underground project, and to pre-embed U-shaped anchor steel bars and steel bar connectors within the concealed columns. When the subsequent access channel construction is carried out later, the pre-embedded steel bar connectors are manually chiseled out, and the steel bars of the subsequent access channel are connected to the connectors, thereby achieving the structural connection between the subsequent access channel and the exterior wall of the existing underground project.

[0004] However, in practical engineering applications, conventional pre-embedded construction methods have many technical problems, specifically: Firstly, due to factors such as deviations in steel bar processing accuracy and errors in on-site binding and positioning operations, pre-embedded steel bar connectors are prone to misalignment and excessive embedment depth, resulting in the connectors being completely hidden inside the concrete of the concealed column without being exposed on the surface of the column. Later, during the construction of the connecting passage, a large amount of manpower and resources are required to remove a large area of ​​concrete from the surface of the connectors, leading to low construction efficiency. Secondly, the concrete removal process easily causes collisions and squeezing damage to the steel bar connectors, resulting in a significant reduction in the survival rate of the connectors. This leads to an insufficient number of effective connections between the steel bars and connectors in the connecting passage. Construction workers subsequently have to supplement the connections by adding chemical anchoring, which not only increases the anchoring construction process and project cost but also significantly reduces the overall connection strength between the connecting passage and the existing underground engineering exterior wall because the connection strength of chemical anchoring is far lower than that of the steel bar connector. This leaves structural safety hazards.

[0005] Therefore, it is urgent for technical personnel to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a method for pre-embedding steel rebar connectors for underground engineering access channels, aiming to solve the problems of easy misalignment and damage during the pre-embedding of connectors and low survival rate in existing designs where the foundation pit support and underground exterior wall are in close contact.

[0007] To address the aforementioned technical problems, this invention relates to a method for pre-embedding steel reinforcement connectors for underground engineering conduits. This method is applicable to the pre-embedding of steel reinforcement connectors for conduits in underground engineering projects where the foundation pit support structure is in close contact with the external wall of the underground engineering structure. The method includes the following construction steps: S1. During the construction phase of the underground project's exterior wall, concealed columns are installed at the pre-set locations of the subsequent access passages; U-shaped anchoring steel bars are laid inside the concealed columns; and steel bar connectors are fixed at the ends of the U-shaped anchoring steel bars. S2. Install an isolation plate between the concealed column of the exterior wall and the foundation pit support structure, and extend the end of the steel bar connector out of the concealed column of the exterior wall and embed it into the isolation plate to a set depth. S3. After bending the horizontal steel bars of the exterior wall around the isolation plate on the outside of the concealed column of the exterior wall, extend them into the concealed column of the exterior wall to complete the anchoring. S4. Pour concrete for the exterior walls of the underground works to complete the forming construction of the exterior walls and hidden columns of the underground works. S5. During the construction phase of the connecting passage, the foundation pit support structure within the construction area of ​​the connecting passage is removed, the isolation plate is exposed and removed, and the exposed surfaces of the hidden columns and steel rebar connectors on the exterior walls are cleaned. S6. Connect the steel reinforcement of the outer wall of the connecting passage to the cleaned steel reinforcement connector, and then construct the reinforced concrete outer wall of the connecting passage so that the connecting passage and the outer wall of the underground project constructed earlier form an integral structure.

[0008] As a further improvement to the technical solution disclosed in this invention, in step S1, the ends of the rebar connector and the U-shaped anchor rebar are fixed by welding or mechanical connection.

[0009] As a further improvement to the technical solution disclosed in this invention, in step S2, the isolation plate is preferably made of lightweight foam board.

[0010] As a further improvement to the technical solution disclosed in this invention, the end of the rebar connector is embedded in the isolation plate at a depth of 25mm to 35mm.

[0011] Of course, as another modified design of the above technical solution, in step S2, the isolation plate can also preferably be a composite isolation plate, which includes an inner rigid support layer and an outer easily peelable buffer layer; the rigid support layer abuts against the side wall of the concealed column of the outer wall, the easily peelable buffer layer abuts against the foundation pit support structure, and the end of the steel bar connector is embedded in the rigid support layer to a set depth.

[0012] As a further improvement to the technical solution disclosed in this invention, the rigid support layer is extruded polystyrene foam board; the easily peelable buffer layer is molded polystyrene foam board; the rigid support layer and the easily peelable buffer layer are bonded and fixed together by a self-adhesive layer, and the thickness of the rigid support layer is greater than the thickness of the easily peelable buffer layer.

[0013] As a further improvement to the technical solution disclosed in this invention, in step S3, the horizontal steel bars of the outer wall are bent at an angle of 1:5 to 1:7 on the outside of the concealed column of the outer wall and then bypass the isolation plate.

[0014] As a further improvement to the technical solution disclosed in this invention, in step S2, the isolation plate is detachably fixed to the external wall hidden column and the foundation pit support structure through the positioning component, and a grouting gap with a width of 5mm to 15mm is reserved between the isolation plate and the external wall hidden column; after step S3 is completed and before step S4, micro-expansion mortar is injected into the grouting gap, and after the micro-expansion mortar is cured, it forms an integral protective layer that adheres to the external wall hidden column and the isolation plate.

[0015] In practical applications, the pre-embedded construction method for rebar connectors in underground engineering conduits disclosed in this invention can achieve at least the following beneficial technical effects: 1) Steps S1 to S4 first involve the installation of concealed columns in the outer wall at the preset position of the connecting channel, the fixed installation of U-shaped anchor steel bars and steel bar connectors in the concealed columns, and then the precise setting of the isolation plate between the concealed column and the foundation pit support structure, so that the end of the steel bar connector is freed from the concrete wrapping and forms a dedicated reserved space. At the same time, combined with the design of the horizontal steel bars of the outer wall being bent around the isolation plate and anchored to the concealed column, not only is the integrity of the main structure of the underground project guaranteed, but the precise pre-embedding of the steel bar connector is also achieved, avoiding the problem of the connector being covered by concrete from the early stage of construction. 2) After the foundation pit support structure is removed in steps S5 to S6, the isolation plate can be directly removed to expose the intact rebar connectors, which greatly simplifies the subsequent cleaning and rebar connection procedures. Combined with the accuracy of the pre-embedded parts, the survival rate of the rebar connectors is maximized, and there is no need to add an additional chemical anchoring process. In this way, not only is the construction cost and construction period reduced, but also the effective mechanical connection of the rebar connectors allows the rebar of the subsequent connecting passage to form a solid structural connection with the outer wall of the underground project, ultimately achieving an integrated connection between the subsequent connecting passage and the outer wall of the underground project constructed in the earlier stage. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a construction diagram of the pre-embedded steel bar connector for the underground engineering connecting channel disclosed in this invention.

[0018] 1-Reinforced concrete exterior wall of underground engineering; 2-Hidden column of exterior wall; 3-Foundation pit support structure; 4-U-shaped anchoring steel bar; 5-Steel bar connector; 6-Isolation plate; 7-Horizontal steel bar of exterior wall; 8-Reinforced concrete exterior wall of rear connecting passage; 9-Steel bar of exterior wall of rear connecting passage. Detailed Implementation

[0019] Given that the expected technical effects are basically the same, namely to achieve accurate pre-embedding of rebar connectors, improve the integrity of connector retention, strengthen the structural connection strength between the subsequent channel and the outer wall of the underground project, and ensure the overall structural stability of the underground project, the pre-embedding construction method for rebar connectors in the subsequent channel of the underground project disclosed in this invention is applicable to the pre-embedding construction of rebar connectors in the subsequent channel under various conditions where the foundation pit support structure and the outer wall of the underground project are in close contact.

[0020] The contents disclosed in this invention will be further described in detail below with reference to specific embodiments. Figure 1 The diagram illustrates the pre-embedded construction structure of the rebar connector for the underground engineering connecting passage disclosed in this invention. It shows that its core structure includes: 1. Reinforced concrete exterior wall of the underground engineering; 2. Hidden columns in the exterior wall; 3. Foundation pit support structure; 4. U-shaped anchoring rebar; 5. Rebar connector; 6. Isolation plate; 7. Horizontal rebar of the exterior wall; 8. Reinforced concrete exterior wall of the connecting passage; and 9. Rebar of the exterior wall of the connecting passage. These structures are arranged collaboratively around the preset positions of the connecting passage, forming a complete pre-embedded connection system. The specific construction method is as follows: S1. During the construction phase of the underground engineering exterior wall, a concealed column 2 is set at the pre-set location of the subsequent passage; U-shaped anchor steel bars 4 are laid in the concealed column 2; steel bar connectors 5 are fixed at the ends of the U-shaped anchor steel bars 4; the ends of the steel bar connectors 5 and the U-shaped anchor steel bars 4 are preferably fixed by welding or mechanical connection to ensure the firmness of the connection and the structural stability. S2. An isolation plate 6 is installed between the concealed column 2 in the outer wall and the foundation pit support structure 3, and the end of the steel bar connector 5 extends out of the concealed column 2 in the outer wall and is embedded in the isolation plate 6 to a set depth. The isolation plate 6 is preferably made of lightweight foam board; the end of the steel bar connector 5 is embedded in the isolation plate 6 at a depth of 25mm to 35mm; Of course, depending on the specific implementation conditions, the isolation plate 6 can also be set as a composite isolation plate, which includes an inner rigid support layer and an outer easily peelable buffer layer; wherein, the rigid support layer is extruded polystyrene foam board, the easily peelable buffer layer is molded polystyrene foam board, the rigid support layer and the easily peelable buffer layer are bonded and fixed together by a self-adhesive layer, and the thickness of the rigid support layer is greater than the thickness of the easily peelable buffer layer. The rigid support layer abuts against the side wall of the concealed column 2 of the exterior wall, the easily peelable buffer layer abuts against the foundation pit support structure 3, and the end of the steel bar connector 5 is embedded in the rigid support layer to a set depth. At the same time, the isolation plate 6 can be detachably fixed to the concealed column 2 of the exterior wall and the foundation pit support structure 3 through the positioning parts, and a grouting gap with a width of 5mm to 15mm is reserved between the isolation plate 6 and the concealed column 2 of the exterior wall. S3. After bending the horizontal steel bar 7 on the outside of the hidden column 2 of the outer wall and bypassing the isolation plate 6, it is inserted into the hidden column 2 of the outer wall to complete the anchorage. The horizontal steel bar 7 on the outside of the hidden column 2 of the outer wall is bent at an angle of 1:5 to 1:7 and then bypassed by the isolation plate 6 to ensure the anchorage stability and structural stress rationality of the steel bar after bending. After this step is completed and before step S4 is started, micro-expansion mortar is injected into the grouting gap. After the micro-expansion mortar has cured, it forms an integral protective layer that adheres to the external wall hidden column 2 and the isolation board 6, preventing the mortar from seeping into the gap during concrete pouring and affecting subsequent construction. S4. Pour concrete for the outer wall of the underground project to complete the forming construction of the reinforced concrete outer wall 1 and the hidden column 2 of the outer wall of the underground project, and ensure the integrity and structural strength of the main structure of the underground project. S5. During the construction phase of the subsequent access channel, the foundation pit support structure 3 within the construction area of ​​the subsequent access channel is removed, the isolation plate 6 is exposed and removed, and the exposed surfaces of the external wall hidden column 2 and the steel bar connector 5 are cleaned to ensure the cleanliness of the connection surface of the steel bar connector 5, so as to provide a good foundation for subsequent steel bar connection. S6. Connect the steel reinforcement 9 of the rear connecting passage outer wall to the cleaned steel reinforcement connector 5, and then construct the reinforced concrete outer wall 8 of the rear connecting passage, so that the rear connecting passage and the reinforced concrete outer wall 1 of the underground project constructed earlier form an integral structure, and realize the firm connection between the rear connecting passage and the main body of the underground project.

[0021] Through the organic coordination of each construction step and the matching layout of each structural component, the overall optimization of pre-embedded construction and structural connection was achieved. The various technical features cooperated to form a complete construction system, resulting in significant construction effects and structural benefits. The entire construction process was carried out in stages and in an orderly manner according to the construction of the underground engineering exterior wall and the subsequent passage construction. From the layout of the exterior wall hidden column 2 at the preset position of the subsequent passage, to the fixed connection of the U-shaped anchor steel bar 4 and the steel bar connector 5, and then to the precise setting of the isolation plate 6 and the bending and anchoring of the exterior wall horizontal steel bar 7, each process was closely connected. This not only ensured the integrity of the main structure composed of the underground engineering reinforced concrete exterior wall 1 and the exterior wall hidden column 2, but also created a dedicated reserved space for the steel bar connector 5 through the isolation plate 6, allowing the end of the steel bar connector 5 to be separated from the concrete wrapping, thus achieving precise pre-embedding of the steel bar connector 5. This ensured the accuracy of the pre-embedding position of the connector from the source of construction. It is particularly noteworthy that during subsequent construction, the intact rebar connectors 5 can be directly exposed by removing the isolation plate 6, eliminating the need for large-scale concrete removal. This significantly simplifies the cleaning and rebar connection procedures. Combined with the precise pre-embedded construction in the early stage, the survival rate of the rebar connectors 5 is maximized, enabling the rebar 9 of the subsequent connecting passage to be effectively mechanically connected to the main body of the underground project through the rebar connectors 5. This eliminates the need for additional chemical anchoring procedures, reducing the consumption of construction manpower and materials, lowering construction costs, and effectively shortening the construction period.

[0022] Finally, it should be emphasized that the material selection and size parameters of the isolation plate 6, the bending angle of the horizontal steel bars 7 of the external wall, the width of the grouting gap, and other construction parameters can all be flexibly adjusted according to the geological conditions and underground engineering structural design requirements of the actual project. Under the premise of ensuring the pre-embedded effect of the steel bar connector 5 and the integrity of the main structure of the underground project, it can adapt to the construction needs of different projects and improve the versatility and engineering adaptability of this construction method.

[0023] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for pre-embedding rebar connectors for underground engineering access channels, applicable to the pre-embedding of rebar connectors for access channels in situations where the foundation pit support structure is in close contact with the external wall of the underground engineering project, characterized in that... The construction steps include the following: S1. During the construction phase of the underground engineering exterior wall, a concealed column is installed at the pre-set location of the subsequent passage; U-shaped anchoring steel bars are installed inside the concealed column; and steel bar connectors are fixed to the ends of the U-shaped anchoring steel bars. S2. An isolation plate is installed between the concealed column of the outer wall and the foundation pit support structure, and the end of the steel bar connector extends out of the concealed column of the outer wall and is embedded in the isolation plate to a set depth. S3. After bending the horizontal steel bars of the outer wall around the isolation plate on the outside of the hidden column of the outer wall, extend them into the hidden column of the outer wall to complete the anchoring. S4. Pour concrete for the outer wall of the underground project to complete the forming construction of the outer wall of the underground project and the hidden columns of the outer wall; S5. During the construction phase of the connecting passage, the foundation pit support structure within the construction area of ​​the connecting passage is removed, the isolation plate is exposed and removed, and the exposed surfaces of the external wall hidden columns and the steel bar connectors are cleaned. S6. Connect the steel reinforcement of the outer wall of the subsequent connecting passage to the cleaned steel reinforcement connector, and then construct the reinforced concrete outer wall of the subsequent connecting passage so that the subsequent connecting passage and the outer wall of the underground project constructed earlier form an integral structure.

2. The method for pre-embedding the reinforcing steel connector for the underground engineering conduit as described in claim 1, characterized in that, In step S1, the rebar connector is fixed to the end of the U-shaped anchor rebar by welding or mechanical connection.

3. The method for pre-embedding the reinforcing steel connector for the underground engineering conduit as described in claim 1, characterized in that, In step S2, the isolation plate is made of lightweight foam board.

4. The method for pre-embedding the reinforcing steel connector for the underground engineering conduit as described in claim 3, characterized in that, The end of the rebar connector is embedded in the isolation plate at a depth of 25mm to 35mm.

5. The method for pre-embedding the reinforcing steel connector for the underground engineering conduit as described in claim 1, characterized in that, In step S2, the isolation plate is a composite isolation plate, which includes an inner rigid support layer and an outer easily peelable buffer layer; the rigid support layer abuts against the side wall of the concealed column of the outer wall, the easily peelable buffer layer abuts against the foundation pit support structure, and the end of the steel bar connector is embedded in the rigid support layer to a set depth.

6. The method for pre-embedding the reinforcing steel connector for the underground engineering conduit as described in claim 5, characterized in that, The rigid support layer is extruded polystyrene foam board; the easily peelable buffer layer is molded polystyrene foam board; the rigid support layer and the easily peelable buffer layer are bonded and fixed together by a self-adhesive layer, and the thickness of the rigid support layer is greater than the thickness of the easily peelable buffer layer.

7. The method for pre-embedding the reinforcing steel connector for the underground engineering conduit as described in claim 1, characterized in that, In step S3, the horizontal steel bars of the outer wall are bent at an angle of 1:5 to 1:7 on the outside of the concealed column of the outer wall and then bypass the isolation plate.

8. The method for pre-embedding the reinforcing steel connector for the underground engineering conduit as described in claim 1, characterized in that, In step S2, the isolation plate is detachably fixed to the concealed column of the outer wall and the foundation pit support structure through the positioning component, and a grouting gap with a width of 5mm to 15mm is reserved between the isolation plate and the concealed column of the outer wall; after step S3 is completed and before step S4, micro-expansion mortar is injected into the grouting gap, and after the micro-expansion mortar is cured, it forms an integral protective layer that adheres to the concealed column of the outer wall and the isolation plate.

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