A railway shield tunnel comprehensive grounding supporting structure and construction method thereof

Abstract

The present invention provides a comprehensive grounding supporting structure for a railway shield tunnel, wherein the inherent structural steel bars in the sub-rail structure are selected to form a sub-rail structure grounding network, which together with other grounding structural facilities constitutes a complete point-through body and is connected to the grounding outside the tunnel. The present invention utilizes the inherent steel bars in the sub-rail structure to form a grounding network, which has good durability and a beneficial grounding effect.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction, and in particular to a railway shield tunnel comprehensive grounding supporting structure and a construction method thereof. Background Art

[0002] Traditional railway tunnels are mostly constructed using the New Austrian Tunneling Method (NATM), but in recent years the shield method has been widely used in railway tunnel construction due to its good safety, fast excavation speed and little impact on the surrounding environment.

[0003] Due to the obvious difference between the shield method and the New Austrian Tunneling Method, shield tunnels cannot use anchor rods, steel frames, grids, etc. as grounding electrodes. Therefore, the structural form of comprehensive grounding supporting facilities for railway shield tunnels is a new technical issue.

[0004] The existing railway shield tunnel comprehensive grounding supporting structure adopts segment bolts, segment bolt connecting steel bars, lead steel bars, longitudinal grounding steel bars on the side wall of the cable trough and grounding terminals to form an electrical connection body and connect it to the grounding body, so as to achieve the grounding effect. However, this method requires additional segment bolt connecting steel bars to weld the exposed segment connecting bolts and lead steel bars, which is difficult to construct. In addition, the bolt connecting steel bars and segment bolts are exposed to the air for a long time during operation. After rusting, the conductivity of the steel bars and bolts decreases, making it difficult to ensure the grounding effect and the failure rate of the grounding system is high.

[0005] Through the above analysis, the problems existing in the prior art are: the existing method requires additional segment bolt connection steel bars to weld the exposed segment connection bolts to the lead-in steel bars, which makes the construction difficult, and the bolt connection steel bars and segment bolts are exposed to the air for a long time during operation. After rusting, the conductivity of the steel bars and bolts decreases, making it difficult to ensure the grounding effect and the failure rate of the grounding system is high. Summary of the invention

[0006] In view of the deficiencies in the above-mentioned prior art, the present invention provides a railway shield tunnel comprehensive grounding supporting structure and a construction method thereof, which utilizes the inherent steel bars in the sub-rail structure to form a grounding network with good durability and beneficial grounding effect.

[0007] The present invention provides the following technical solutions:

[0008] The railway shield tunnel comprehensive grounding supporting structure selects the inherent structural steel bars in the sub-track structure to form a sub-track structure grounding network, which together with other grounding structure facilities constitutes a complete point system and is connected to the grounding outside the tunnel.

[0009] Among them, other grounding structural facilities include longitudinal grounding steel bars arranged on the side walls of the communication cable trough, and through-ground wires, grounding terminals, and connecting steel bars arranged at the bottom of the communication cable trough. The connecting steel bars connect the terminal blocks, the longitudinal grounding steel bars on the side walls of the cable trough, and the through-ground wires into a complete electrical path.

[0010] Furthermore, the longitudinal grounding steel bars on the side walls of the cable trough are cut off every time they extend a certain distance; the through ground wire is laid at the bottom of the communication cable trough and connected to the ground outside the tunnel, while sand protection is performed; the connecting steel bars are A16 connecting steel bars.

[0011] Furthermore, the grounding terminal is composed of a cable trough side wall grounding terminal and a cable trough bottom grounding terminal; the cable trough side wall grounding terminals are arranged on the side walls of the communication cable trough at a certain interval, and are used to provide grounding ports for electrical equipment in the tunnel; the cable trough bottom grounding terminals are arranged at a certain interval at the bottom of the communication cable trough, and are used to provide a connection port for connecting the steel bars to the through-ground wire.

[0012] Furthermore, the outer edge of the longitudinal grounding steel bar on the side wall of the cable trough is not less than 30 mm away from the outer surface of the reinforced concrete and is cut off every 50-200 m; and the grounding terminal is set every 50-100 m.

[0013] Among them, the sub-rail structure grounding network is composed of the sub-rail structure longitudinal grounding steel bars and the sub-rail structure annular grounding steel bars in the sub-rail structure. The longitudinal grounding steel bars of the sub-rail structure are selected from the longitudinal structural steel bars of the sub-rail structure at a certain interval, and the annular grounding steel bars of the sub-rail structure are selected from the annular structural steel bars of the sub-rail structure at a certain interval; the sub-rail structure has multiple structural blocks, and each structural block has the sub-rail structure longitudinal grounding steel bars and the sub-rail structure annular grounding steel bars; the steel bars between adjacent structural blocks, as well as the sub-rail structure longitudinal grounding steel bars and the sub-rail structure annular grounding steel bars in the structural blocks are all connected by steel sleeves or welding to form an electrical path.

[0014] Wherein, the resistance of the grounding supporting structure is not greater than 1 ohm.

[0015] The present invention also provides a construction method for the above-mentioned railway shield tunnel comprehensive grounding supporting structure, comprising the following steps:

[0016] S1: Select longitudinal grounding steel bars and circumferential grounding steel bars in the rail structure at a certain interval, and make stable connections between the steel bars to form an electrical path;

[0017] S2: Leading steel bars are laid at a certain interval along the longitudinal direction of the tunnel, and the leading steel bars are firmly connected to the annular grounding steel bars of the sub-rail structure to form an electrical path;

[0018] S3: After the sub-rail structure is cast, tie the communication cable trough steel bars and lay the longitudinal grounding steel bars on the side walls of the communication cable trough;

[0019] S4: Grounding terminals on the side walls and bottom of the communication cable trough are embedded at a certain distance;

[0020] S5: firmly connect the grounding terminal of the cable trough side wall, the grounding terminal of the cable trough bottom and the longitudinal grounding steel bars of the cable trough side wall to the lead-in steel bars to form an electrical path;

[0021] S6: Cast the communication cable trough, lay the through ground wire at the bottom of the communication cable trough, weld the through ground wire to the terminal firmly to form an electrical path, and connect it to the ground outside the tunnel.

[0022] Wherein, the step S1 specifically includes the following steps:

[0023] S11: In the prefabricated box culvert under the track structure, longitudinal grounding steel bars and circumferential grounding steel bars of the under-track structure are selected at a certain interval, and the steel bars are connected by steel sleeves or welding to form an electrical path;

[0024] S12: After the prefabricated box culvert under the track structure is assembled in place, the cast-in-place side box culvert reinforcement is tied, and the longitudinal grounding reinforcement of the track structure and the circumferential grounding reinforcement of the track structure are selected at a certain interval. The reinforcements are connected by steel sleeves or welding to form an electrical path;

[0025] S13: The middle box culvert and the side box culvert are also connected by steel sleeves or welding to form an electrical path between the box culverts.

[0026] Wherein, the step S6 also includes performing sand protection at the bottom of the communication cable trough.

[0027] Among them, all grounding terminals are connected to the longitudinal grounding steel bars on the side walls of the cable trough through A16 lead-in steel bars; the intersections of the grounding steel bars are welded with A16 steel bars in L-shape; the welding quality of all connections between the grounding steel bars should be guaranteed, the lap length of single-sided welding should not be less than 10d, and the lap length of double-sided welding should not be less than 5d, where d is the diameter of the steel bar.

[0028] Compared with the prior art, the advantages and positive effects of the present invention are: simple structure, easy implementation, all grounding materials except the through ground wire and the grounding terminal are buried in the concrete structure and are not easy to corrode, the grounding materials are all taken from the inherent steel bars of the structure, and no additional special materials are required, thereby achieving the purpose of speeding up the project progress, reducing project investment, increasing the durability of the grounding system, reducing its failure rate and ensuring a good grounding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1It is a cross-sectional schematic diagram of an example of the comprehensive grounding supporting structure of the present invention.

[0030] Figure 2 It is a longitudinal structural schematic diagram of an example of the comprehensive grounding supporting structure of the present invention.

[0031] Figure 3 yes Figure 1 A partial enlargement of the lower right part.

[0032] Among them: 1. Shield segment; 2. Tunnel center line; 3. Line center line; 4. Sub-track structure; 5. Communication cable trough; 6. Longitudinal grounding steel bars of sub-track structure; 7. Circumferential grounding steel bars of sub-track structure; 8. Grounding terminal of cable trough side wall; 9. Grounding terminal of cable trough bottom; 10. Longitudinal grounding steel bars of cable trough side wall; 11. Through ground wire; 12. Lead-in steel bars; 13. Steel sleeve. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] like Figure 1-3 As shown, the railway shield tunnel comprehensive grounding supporting structure of the present invention is composed of the rail structure grounding network arranged in the rail structure 4, the longitudinal grounding steel bars 10 of the cable trough side wall arranged in the communication cable trough 5, the through ground wire 11, the lead steel bars 12 and the grounding terminal, which together form a complete point through body and are connected to the ground outside the tunnel. The longitudinal grounding steel bars 10 of the cable trough side wall are cut off once every extended distance, such as once every 100m, and their function is to dissipate the short-circuit current generated in the tunnel section within the pipe segment range, such as the pipe segment range within the 50 ring, to reduce the impact on other pipe segments.

[0035] The grounding network of the sub-rail structure is composed of the longitudinal grounding steel bars 6 of the sub-rail structure and the annular grounding steel bars 7 of the sub-rail structure. The longitudinal grounding steel bars 6 of the sub-rail structure are selected from the longitudinal structural steel bars of the sub-rail structure at a certain interval. The annular grounding steel bars 7 of the sub-rail structure are selected from the annular structural steel bars of the sub-rail structure at a certain interval. The grounding steel bars are all inherent to the structure and do not need to be added additionally. The sub-rail structure 4 can have multiple structural blocks. For example, the sub-rail structure 4 in the figure of this embodiment is divided into three structural blocks, which are respectively cast by a middle box culvert and two side box culverts on both sides. Each structural block has the longitudinal grounding steel bars 6 of the sub-rail structure and the annular grounding steel bars 7 of the sub-rail structure. The steel bars between adjacent structural blocks and the steel bars in the structural blocks can be connected by steel sleeves 13 or welded to form an electrical path.

[0036] The through ground wire 11 is laid at the bottom of the communication cable trough 5 and is protected from sand and connected to the ground outside the tunnel.

[0037] The grounding terminal is composed of a cable trough side wall grounding terminal 8 and a cable trough bottom grounding terminal 9. The cable trough side wall grounding terminal 8 is arranged at a certain interval in the side wall of the communication cable trough 5, and its function is to serve as a grounding port connected to the electrical equipment in the tunnel, thereby leading out the short-circuit current of the electrical equipment in the tunnel. The cable trough bottom grounding terminal 9 is arranged at a certain interval at the bottom of the communication cable trough, and its function is to serve as a connection port for connecting the steel bar 12 with the through ground wire 11, so that the current in the grounding network of the sub-rail structure is introduced into the through ground wire 11 through the grounding terminal 9 to achieve grounding outside the tunnel.

[0038] The lead-in steel bars 12 are arranged at a certain interval along the longitudinal direction of the tunnel. The grounding steel bars 6, 7 of the sub-rail structure, the longitudinal grounding steel bars 10 of the cable trough side walls, the through ground wires 11 and the grounding terminals 8, 9 are firmly connected by welding to form a complete electrical conductor, which is then connected to the ground outside the tunnel through the through ground wires 11.

[0039] The implementation process of the present invention comprises the following steps:

[0040] First, in the prefabricated box culvert under the track structure, longitudinal grounding steel bars 6 and annular grounding steel bars 7 of the under-track structure are selected at a certain interval, and the steel bars are connected by steel sleeves 13 or welding to form an electrical path.

[0041] After the prefabricated box culvert under the track structure is assembled in place, the cast-in-place side box culvert reinforcement is tied, and the longitudinal grounding reinforcement 6 and the annular grounding reinforcement 7 of the under-track structure are selected at a certain interval. The reinforcements are connected by reinforcement sleeves 13 or welding to form an electrical path.

[0042] A steel sleeve 13 or selected steel bars are also used between the middle box culvert and the side box culvert to form an electrical path between the box culverts.

[0043] Leading steel bars 12 are arranged at a certain interval along the longitudinal direction of the tunnel, and the leading steel bars are firmly welded to the annular grounding steel bars 7 of the sub-rail structure to form an electrical path.

[0044] After casting the cast-in-place side box culvert of the rail substructure, the communication cable trough 5 steel bars are tied, and the longitudinal grounding steel bars 10 of the cable trough side wall are arranged at the position of the communication cable trough 5 side wall.

[0045] Grounding terminals 8 on the side walls and 9 on the bottom of the communication cable trough 5 are embedded at certain intervals. The grounding terminals 8, 9 and the longitudinal grounding steel bars 10 on the side walls of the cable trough are welded firmly to the connecting steel bars 12 to form an electrical path.

[0046] A cast-in-situ communication cable duct 5 is cast in the rail substructure, and a through ground wire 11 is laid at the bottom of the communication cable duct 5. The through ground wire 11 and the connection terminal 9 are firmly welded to form an electrical path, and then connected to the ground outside the tunnel.

[0047] The bottom of the communication cable trough 5 is protected by sand.

[0048] The technical requirements for the implementation of the present invention are as follows:

[0049] In the prefabricated middle box culvert and cast-in-place side box culvert of the tunnel track structure, the longitudinal structural steel bars are selected at intervals of 1m as the longitudinal grounding steel bars 6 of the track structure.

[0050] In each operation section of the longitudinal grounding steel bars of the sub-track structure (length 2m, the same as the length of each ring of the shield segment, and one is set every 2 rings of segments), select 2 annular structural steel bars as the annular grounding steel bars 7 of the sub-track structure. The annular and longitudinal grounding steel bars can be reliably welded, and the annular grounding steel bars should be connected to the two through ground wires 11 on both sides.

[0051] The annular grounding steel bars 7 of the sub-rail structure in each working section (2 m) are connected to the longitudinal grounding steel bars 10 of the cable trough side walls of the communication cable troughs 5 on both sides close to the outer edge of the line side through connecting steel bars 12 .

[0052] The longitudinal grounding steel bars 10 (with a diameter of not less than 16 mm) on the upper side walls of the communication cable trough 5 are used as the longitudinal grounding steel bars on the side walls of the cable trough. The outer edge of the longitudinal grounding steel bars 10 on the side walls of the cable trough is not less than 30 mm from the outer surface of the reinforced concrete and is disconnected every 100 m.

[0053] The grounding terminals are all bridge-tunnel type grounding terminals.

[0054] A grounding terminal is set every 100m at the bottom of the communication cable trough for connection between the tunnel grounding device and the through ground wire.

[0055] A grounding terminal is set every 50m on the side wall of the communication cable trough.

[0056] All grounding terminals are connected to the longitudinal grounding steel bars 10 on the side walls of the cable trough via A16 lead-in steel bars 12.

[0057] The welding quality of all grounding steel bars should be guaranteed, and the lap length of single-side welding should not be less than 10d, and the lap length of double-side welding should not be less than 5d, where d is the diameter of the steel bar. The intersection of grounding steel bars should be welded with A16 steel bar L-type, and the welding length is the same as the above requirements.

[0058] An A16 longitudinal through-ground wire 11 is laid in the communication cable trough 5 along the line in the tunnel and is connected to the ground outside the tunnel.

[0059] Sand protection measures are taken at the bottom of the communication cable trough.

[0060] After the grounding project is completed, a resistance test should be carried out to ensure that the resistance is no greater than 1 ohm to meet the grounding requirements.

[0061] Practice has proved that the railway shield tunnel comprehensive grounding supporting structure of the present invention has a simple structure and is easy to implement. Except for the through ground wire and the grounding terminal, other grounding materials are buried in the concrete structure and are not easy to corrode. The grounding materials are all taken from the inherent steel bars of the structure, and no additional special materials are required. Therefore, the purpose of accelerating the progress of the project, reducing the project investment, increasing the durability of the grounding system, reducing its failure rate and ensuring a good grounding effect can be achieved.

[0062] The protection scope of the present invention is not limited thereto, and any person skilled in the art can easily make changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A railway shield tunnel integrated grounding supporting structure, wherein the structural steel bars inherent in the sub-track structure (4) are selected to form a sub-track structure grounding network, which together with other grounding structural facilities forms a complete point body and is connected to the tunnel external grounding; The track structure grounding network is composed of track structure longitudinal grounding steel bars (6) and track structure annular grounding steel bars (7) in the track structure (4); the track structure longitudinal grounding steel bars (6) are selected from the track structure longitudinal structural steel bars at a certain interval, and the track structure annular grounding steel bars (7) are selected from the track structure annular structural steel bars at a certain interval; the track structure (4) has a plurality of structural blocks, each structural block has track structure longitudinal grounding steel bars (6) and track structure annular grounding steel bars (7); the steel bars between adjacent structural blocks, and the track structure longitudinal grounding steel bars (6) and track structure annular grounding steel bars (7) in the structural blocks are all connected by steel sleeves (13) or welded to form an electrical path; Other grounding structural facilities include longitudinal grounding steel bars (10) arranged on the side walls of the communication cable trough (5), a through ground wire (11), a grounding terminal, and a connecting steel bar (12) arranged at the bottom of the communication cable trough (5), wherein the connecting steel bar (12) connects the grounding terminal, the longitudinal grounding steel bars (10) on the side walls of the cable trough (5), and the through ground wire (11) into a complete electrical path; The grounding terminal is composed of a cable trough side wall grounding terminal (8) and a cable trough bottom grounding terminal (9); the cable trough side wall grounding terminal (8) is arranged at a certain interval in the side wall of the communication cable trough (5) and is used to provide a grounding port for electrical equipment in the tunnel; the cable trough bottom grounding terminal (9) is arranged at a certain interval at the bottom of the communication cable trough (5) and is used to provide a connection port for connecting the lead-in steel bar (12) to the through ground wire (11).

2. The railway shield tunnel comprehensive grounding supporting structure according to claim 1 is characterized in that: The longitudinal grounding steel bars (10) on the side walls of the cable trough are cut off once each time they extend a certain distance; the through ground wire (11) is laid at the bottom of the communication cable trough (5) and connected to the ground outside the tunnel, while sand protection is performed; the connecting steel bars (12) are A16 connecting steel bars.

3. The railway shield tunnel comprehensive grounding supporting structure according to claim 2 is characterized in that: The outer edge of the longitudinal grounding steel bar (10) on the side wall of the cable trough is not less than 30 mm from the outer surface of the reinforced concrete and is cut off every 50-200 m; and the grounding terminal is arranged every 50-100 m.

4. The railway shield tunnel comprehensive grounding supporting structure according to claim 1 is characterized in that: The resistance of the grounding supporting structure is not greater than 1 ohm.

5. A construction method for a railway shield tunnel comprehensive grounding supporting structure according to any one of claims 1 to 4, comprising the following steps: S1: Selecting longitudinal grounding steel bars (6) and annular grounding steel bars (7) of the sub-rail structure in the sub-rail structure (4) at a certain interval, and stably connecting the steel bars to form an electrical path; S2: Leading steel bars (12) are arranged at a certain interval along the longitudinal direction of the tunnel, and the leading steel bars (12) are firmly connected to the annular grounding steel bars (7) of the sub-rail structure to form an electrical path; S3: After the sub-rail structure (4) is cast, the communication cable trough (5) reinforcement is tied, and the longitudinal grounding reinforcement (10) of the side wall of the communication cable trough (5) is arranged at the side wall of the communication cable trough (5); S4: pre-embed the cable trough side wall grounding terminal (8) and the cable trough bottom grounding terminal (9) at a certain interval on the side wall and bottom of the communication cable trough (5); S5: firmly connecting the cable trough side wall grounding terminal (8), the cable trough bottom grounding terminal (9) and the cable trough side wall longitudinal grounding steel bar (10) to the lead steel bar (12) to form an electrical path; S6: Cast the communication cable trough (5), lay the through-ground wire (11) at the bottom of the communication cable trough (5), firmly weld the through-ground wire (11) and the grounding terminal (9) at the bottom of the cable trough to form an electrical path, and connect it to the ground outside the tunnel.

6. The construction method of the railway shield tunnel comprehensive grounding supporting structure according to claim 5 is characterized in that: The step S1 specifically includes the following steps: S11: In the prefabricated box culvert of the under-rail structure, longitudinal grounding steel bars (6) and annular grounding steel bars (7) of the under-rail structure are selected at a certain interval, and the steel bars are connected by steel sleeves (13) or welded to form an electrical path; S12: After the prefabricated middle box culvert of the under-track structure is assembled in place, the cast-in-place side box culvert reinforcement is tied, and longitudinal grounding reinforcements (6) of the under-track structure and annular grounding reinforcements (7) of the under-track structure are selected at a certain interval, and the reinforcements are connected by reinforcement sleeves (13) or welding to form an electrical path; S13: A steel sleeve (13) or selected steel bars are also connected by welding between the middle box culvert and the side box culvert, thereby forming an electrical path between the box culverts.

7. The construction method of the railway shield tunnel comprehensive grounding supporting structure according to claim 5 is characterized in that: The step S6 further comprises performing sand protection at the bottom of the communication cable trough (5); All grounding terminals are connected to the longitudinal grounding steel bars (10) on the side walls of the cable trough through A16 lead-in steel bars (12). The intersections of the grounding steel bars are welded with A16 steel bars in L-shaped pattern. The welding quality of all connections between the grounding steel bars should be guaranteed. The lap length of single-sided welding should be not less than 10d, and the lap length of double-sided welding should be not less than 5d, where d is the diameter of the steel bar.

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