1. A railway shield tunnel comprehensive grounding matching structure is characterized in that structural steel bars inherent in a rail lower structure (4) are selected to form a rail lower structure grounding network, and the rail lower structure grounding network and other grounding structure facilities form a complete point whole body and are led to the outside of a tunnel to be grounded.

2. The railway shield tunnel comprehensive grounding matching structure as claimed in claim 1, wherein other grounding structure facilities comprise cable trough side wall longitudinal grounding steel bars (10) arranged on the side wall of the communication cable trough (5), and through ground wires (11), grounding terminals and lead-in steel bars (12) arranged at the bottom in the communication cable trough (5), wherein the lead-in steel bars (12) connect the wiring terminals, the cable trough side wall longitudinal grounding steel bars (10) and the through ground wires (11) into a complete electric path.

3. The railway shield tunnel comprehensive grounding matching structure as claimed in claim 2, wherein the longitudinal grounding steel bars (10) on the side wall of the cable trough are cut off every time the longitudinal grounding steel bars extend for a certain distance; the through ground wire (11) is laid at the bottom of the communication cable trough (5), is led to the outside of the tunnel to be grounded and is used for sand protection; the leading and connecting steel bar (12) is an A16 leading and connecting steel bar.

4. The railway shield tunnel comprehensive grounding matching structure as claimed in claim 2, wherein 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 terminals (8) are arranged in the side wall of the communication cable trough (5) at certain intervals and are used for providing grounding ports for electric equipment in the tunnel; the grounding terminal (9) at the bottom of the cable slot is arranged at the bottom of the communication cable slot at a certain interval and is used for providing a connecting port connected with a through ground wire (11) for leading-in reinforcing steel bars (12).

5. The railway shield tunnel comprehensive grounding matching structure as claimed in claim 2, wherein the distance from the outer edge of the longitudinal grounding steel bar (10) on the side wall of the cable trough to the outer surface of the reinforced concrete is not less than 30mm, and the longitudinal grounding steel bar is cut off every 50-200 m; the ground terminals are arranged at every 50-100 m.

6. The railway shield tunnel comprehensive grounding matching structure as claimed in claim 1, wherein the under-rail structure grounding network is composed of under-rail structure longitudinal grounding steel bars (6) and under-rail structure circumferential grounding steel bars (7) in the under-rail structure (4), the under-rail structure longitudinal grounding steel bars (6) are selected from the under-rail structure longitudinal structural steel bars at certain intervals, and the under-rail structure circumferential grounding steel bars (7) are selected from the under-rail structure circumferential structural steel bars at certain intervals; the rail lower structure (4) is provided with a plurality of structural blocks, and each structural block is internally provided with a rail lower structure longitudinal grounding steel bar (6) and a rail lower structure circumferential grounding steel bar (7); the steel bars between the adjacent structural blocks, and the under-rail structure longitudinal grounding steel bars (6) and the under-rail structure circumferential grounding steel bars (7) in the structural blocks are connected by steel bar sleeves (13) or welded to form an electric path.

7. The railway shield tunnel integrated grounding complete set structure of claim 1, wherein the grounding complete set structure resistance is not more than 1 ohm.

8. The construction method of the railway shield tunnel comprehensive grounding complete set structure as claimed in any one of claims 1 to 7, comprising the steps of:

s1: according to a certain distance, selecting a longitudinal grounding steel bar (6) of the under-rail structure and a circumferential grounding steel bar (7) of the under-rail structure from the under-rail structure (4), and stably connecting the steel bars to form an electric path;

s2: leading-in reinforcing steel bars (12) are arranged at certain intervals along the longitudinal direction of the tunnel, and the leading-in reinforcing steel bars (12) are firmly connected with the annular grounding reinforcing steel bars (7) of the under-rail structure to form an electric path;

s3: after the under-rail structure (4) is poured, binding reinforcing steel bars of the communication cable trough (5), and arranging longitudinal grounding reinforcing steel bars (10) on the side wall of the communication cable trough (5);

s4: embedding a cable trough side wall grounding terminal (8) and a cable trough bottom grounding terminal (9) at the side wall and the bottom of a communication cable trough (5) respectively according to a certain interval;

s5: the method comprises the following steps that a cable trough side wall grounding terminal (8), a cable trough bottom grounding terminal (9) and a cable trough side wall longitudinal grounding steel bar (10) are respectively and firmly connected with a leading steel bar (12) to form an electric path;

s6: and pouring a communication cable groove (5), laying a through ground wire (11) at the bottom of the communication cable groove (5), and firmly welding the through ground wire (11) and the wiring terminal (9) to form an electric path and leading the electric path to the outside of the tunnel for grounding.

9. The construction method of the comprehensive grounding matching structure of the railway shield tunnel according to claim 8, wherein the step S1 specifically comprises the following steps:

s11: longitudinal grounding steel bars (6) and circumferential grounding steel bars (7) of the under-rail structure are selected at certain intervals in the box culvert in the prefabrication of the under-rail structure, and the steel bars are connected or welded by steel bar sleeves (13) to form an electric path;

s12: after the box culvert is assembled in place in the prefabrication of the under-rail structure, binding cast-in-place side box culvert reinforcing steel bars, selecting under-rail structure longitudinal grounding reinforcing steel bars (6) and under-rail structure circumferential grounding reinforcing steel bars (7) according to a certain interval, and connecting or welding the reinforcing steel bars by using reinforcing steel bar sleeves (13) to form an electric path;

s13: the selected steel bars are connected between the middle box culvert and the side box culverts by steel bar sleeves (13) or welding, so that an electric path between the box culverts is formed.

10. The construction method of the comprehensive grounding complete set structure of the railway shield tunnel according to claim 8, wherein the step S6 further comprises performing sand protection at the bottom of the communication cable trough (5);

all the grounding terminals are connected with the longitudinal grounding steel bars (10) on the side wall of the cable trough through A16 leading-in steel bars (12); the cross point of the grounding steel bar is welded by an A16 steel bar L shape; all the connections between the grounding steel bars are required to ensure the welding quality, the lap length of the single-side welding is not less than 10d, and the lap length of the double-side welding is not less than 5d, wherein d is the diameter of the steel bar.

Background

The traditional railway tunnel is mostly constructed by adopting a new Olympic method, but in recent years, the shield method is widely applied to railway tunnel construction due to the characteristics of good safety and quick tunneling speed, and small influence on the surrounding environment.

Due to the obvious difference between the shield method and the new Austrian method, the shield tunnel cannot utilize anchor rods, steel frames, grids and the like as a grounding electrode, so that the structural form of the railway shield tunnel which is comprehensively grounded and matched is a new technical problem.

The existing railway shield tunnel comprehensive grounding matching structure form adopts a duct piece bolt, a duct piece bolt connecting steel bar, a leading steel bar, a cable duct side wall longitudinal grounding steel bar and a grounding terminal to jointly form a power-on body and be connected with the grounding body, thereby achieving the grounding effect. However, in the method, the segment bolt connecting steel bars need to be additionally arranged to weld the segment connecting bolts and the leading steel bars on the exposed parts, the construction difficulty is high, the bolt connecting steel bars and the segment bolts are exposed in the air for a long time during operation, the electric conductivity of the steel bars and the bolts is reduced after corrosion, the grounding effect is difficult to guarantee, and the failure rate of a grounding system is high.

Through the analysis, the problems of the prior art are as follows: in the existing method, additionally-arranged segment bolt connecting steel bars are needed to weld the segment connecting bolts and the leading steel bars on the exposed parts, the construction difficulty is high, the bolt connecting steel bars and the segment bolts are exposed in the air for a long time in the operation period, the electric conductivity of the steel bars and the bolts is reduced after corrosion, the grounding effect is difficult to guarantee, and the failure rate of a grounding system is high.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a railway shield tunnel comprehensive grounding matching structure and a construction method thereof.

The invention provides the following technical scheme:

the railway shield tunnel comprehensive grounding matching structure selects the inherent structural steel bars in the under-rail structure to form an under-rail structure grounding network, and forms a complete point whole body together with other grounding structure facilities and is led to the outside of the tunnel for grounding.

The other grounding structure facilities comprise cable trough side wall longitudinal grounding steel bars arranged on the side wall of the communication cable trough, through ground wires arranged at the bottom in the communication cable trough, grounding terminals and leading steel bars, wherein the leading steel bars connect the wiring terminals, the cable trough side wall longitudinal grounding steel bars and the through ground wires into a complete electric path.

Further, the longitudinal grounding steel bars on the side wall of the cable trough are cut off once when extending for a certain distance; the through ground wire is laid at the bottom of the communication cable trough and is led to the outside of the tunnel for grounding, and meanwhile, sand protection is carried out; the leading and connecting steel bar is A16 leading and connecting steel bar.

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 distributed on the communication cable trough side wall at certain intervals and used for providing grounding ports for electric equipment in the tunnel; the cable slot bottom grounding terminal is arranged at the bottom of the communication cable slot at a certain interval and used for providing a connecting port connected with a through ground wire for leading-in reinforcing steel bars.

Further, the distance between the outer edge of the longitudinal grounding steel bar on the side wall of the cable trough and the outer surface of the reinforced concrete is not less than 30mm, and the longitudinal grounding steel bar is cut off every 50-200 m; the ground terminals are arranged at every 50-100 m.

The under-rail structure grounding network consists of under-rail structure longitudinal grounding steel bars and under-rail structure circumferential grounding steel bars, wherein the under-rail structure longitudinal grounding steel bars are selected from the under-rail structure longitudinal structural steel bars at certain intervals; the under-rail structure is provided with a plurality of structural blocks, and each structural block is internally provided with an under-rail structure longitudinal grounding steel bar and an under-rail structure circumferential grounding steel bar; the steel bars between the adjacent structural blocks, the under-rail structure longitudinal grounding steel bars in the structural blocks and the under-rail structure circumferential grounding steel bars in the structural blocks are connected by steel bar sleeves or welded to form an electric path.

And the resistance of the grounding matching structure is not more than 1 ohm.

The invention also provides a construction method of the railway shield tunnel comprehensive grounding matching structure, which comprises the following steps:

s1: according to a certain distance, selecting a longitudinal grounding steel bar of the under-rail structure and a circumferential grounding steel bar of the under-rail structure from the under-rail structure, and stably connecting the steel bars to form an electric path;

s2: leading connecting reinforcing steel bars are arranged at certain intervals along the longitudinal direction of the tunnel, and the leading connecting reinforcing steel bars are firmly connected with the annular grounding reinforcing steel bars of the under-rail structure to form an electric path;

s3: binding communication cable trough reinforcing steel bars after the under-rail structure is poured, and laying cable trough side wall longitudinal grounding reinforcing steel bars at the side wall positions of the communication cable troughs;

s4: embedding a cable slot side wall grounding terminal and a cable slot bottom grounding terminal at the side wall and the bottom of a communication cable slot respectively according to a certain interval;

s5: the grounding terminal on the side wall of the cable trough, the grounding terminal at the bottom of the cable trough and the longitudinal grounding steel bar on the side wall of the cable trough are respectively and firmly connected with the leading steel bar to form an electric path;

s6: and pouring a communication cable groove, laying a through ground wire at the bottom of the communication cable groove, and firmly welding the through ground wire and the wiring terminal to form an electric path and leading the electric path to the outside of the tunnel for grounding.

Wherein the step S1 specifically includes the following steps:

s11: longitudinal grounding steel bars of the under-rail structure and circumferential grounding steel bars of the under-rail structure are selected at certain intervals in the box culvert in the prefabrication of the under-rail structure, and the steel bars are connected by steel bar sleeves or welded connection to form an electric path;

s12: after the box culvert is assembled in place in the prefabrication of the under-rail structure, binding cast-in-place side box culvert reinforcing steel bars, selecting longitudinal grounding reinforcing steel bars of the under-rail structure and circumferential grounding reinforcing steel bars of the under-rail structure according to a certain interval, and connecting the reinforcing steel bars by using reinforcing steel bar sleeves or welding to form an electric path;

s13: and the middle box culvert and the side box culverts are also connected with selected steel bars by steel bar sleeves or welding, so that an electric path between the box culverts is formed.

Wherein the step S6 further includes performing sand protection at the bottom of the communication cable trough.

All the grounding terminals are connected with the longitudinal grounding steel bars on the side wall of the cable trough through A16 leading-in steel bars; the cross point of the grounding steel bar is welded by an A16 steel bar L shape; all the connections between the grounding steel bars are required to ensure the welding quality, the lap length of the single-side welding is not less than 10d, and the lap length of the double-side welding is not less than 5d, wherein d is the diameter of the steel bar.

Compared with the prior art, the invention has the advantages and positive effects that: the grounding system has the advantages of simple structure, convenient implementation, and difficult corrosion of other grounding materials except the through ground wire and the grounding terminal, the grounding materials are all taken from inherent structural steel bars, and special materials do not need to be additionally arranged, so that the purposes of accelerating the engineering progress, reducing the engineering investment, increasing the durability of the grounding system, reducing the failure rate and ensuring good grounding effect are achieved.

Drawings

Fig. 1 is a schematic cross-sectional view of an example of an integrated grounding kit according to the present invention.

Fig. 2 is a schematic longitudinal structure diagram of an example of the integrated grounding kit structure of the present invention.

Fig. 3 is a partially enlarged view of the lower right portion of fig. 1.

Wherein: 1. a shield segment; 2. a tunnel centerline; 3. a line neutral line; 4. an under-track structure; 5. a communication cable slot; 6. longitudinally grounding the steel bars of the under-rail structure; 7. the under-rail structure is a circumferential grounding steel bar; 8. a cable trough side wall ground terminal; 9. a cable trough bottom ground terminal; 10. longitudinal grounding steel bars on the side wall of the cable trough; 11. a through ground wire; 12. leading and connecting steel bars; 13. and (4) a steel bar sleeve.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

As shown in fig. 1-3, the comprehensive grounding supporting structure for the railway shield tunnel of the present invention is formed by a grounding network of the under-rail structure arranged in the under-rail structure 4, longitudinal grounding steel bars 10 arranged on the side wall of the cable trough arranged in the communication cable trough 5, a through ground wire 11, a lead-through steel bar 12 and a grounding terminal, which together form a complete point-through body and lead to the outside of the tunnel for grounding. Wherein the vertical ground connection reinforcing bar 10 of cable duct lateral wall is once cuted every a distance of extension, if once cuted every 100m, its effect is in the section of jurisdiction within range at its place with the short-circuit current dissipation that produces in the tunnel of this section, like the section of jurisdiction within the 50 rings within range, reduces the influence to other sections of jurisdiction.

The grounding network of the under-rail structure consists of longitudinal grounding steel bars 6 of the under-rail structure and circumferential grounding steel bars 7 of the under-rail structure. The longitudinal grounding steel bars 6 of the under-rail structure are selected from the longitudinal structural steel bars of the under-rail structure at certain intervals. The circumferential grounding steel bars 7 of the under-rail structure are selected from the circumferential structural steel bars of the under-rail structure at certain intervals, and the steel bars for grounding are self-existing structures and do not need to be additionally arranged. The structure 4 under the rail can have a plurality of structure pieces, if the structure 4 under the rail in this embodiment picture divide into three structure pieces, pour by two limit box culverts of box culvert and both sides in one respectively and form, have the longitudinal ground connection reinforcing bar 6 of structure under the rail and the annular ground connection reinforcing bar 7 of structure under the rail in every structure piece separately. The reinforcing steel bars between the adjacent structural blocks and the reinforcing steel bars in the structural blocks can be connected by a reinforcing steel bar sleeve 13 or welded to form an electric path.

The through ground wire 11 is laid at the bottom of the communication cable groove 5, is subjected to sand protection and is led to the outside of the tunnel for grounding.

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 terminals 8 are arranged in the side wall of the communication cable trough 5 at certain intervals and can be used as grounding ports connected with electric equipment in the tunnel, so that short-circuit current of the electric equipment in the tunnel is led out. The grounding terminals 9 at the bottom of the cable slot are arranged at the bottom of the communication cable slot at certain intervals and can be used as connecting ports for connecting the leading reinforcing steel bars 12 and the through ground wires 11, so that current in the grounding network of the under-rail structure is led into the through ground wires 11 through the grounding terminals 9 to be led out of the tunnel for grounding.

The leading and connecting steel bars 12 are arranged at a certain interval along the longitudinal direction of the tunnel, the grounding steel bars 6 and 7 of the under-rail structure, the longitudinal grounding steel bar 10 of the side wall of the cable trough, the through ground wire 11 and the grounding terminals 8 and 9 are firmly connected in a welding mode to form a complete electric conduction body, and then the whole electric conduction body is led and connected to the outside of the tunnel through the through ground wire 11 for grounding.

The implementation process of the invention comprises the following steps:

firstly, selecting the longitudinal grounding steel bars 6 of the under-rail structure and the circumferential grounding steel bars 7 of the under-rail structure at certain intervals in the box culvert in the prefabrication of the under-rail structure, and connecting the steel bars by using a steel bar sleeve 13 or welding to form an electric path.

After the box culvert is assembled in place in the prefabrication of the under-rail structure, reinforcing steel bars of the box culvert at the cast-in-place side are bound, longitudinal grounding reinforcing steel bars 6 of the under-rail structure and annular grounding reinforcing steel bars 7 of the under-rail structure are selected according to a certain interval, and reinforcing steel bars are connected or welded by using reinforcing steel bar sleeves 13 to form an electric path.

And the middle box culvert and the side box culverts are also connected with selected steel bars by adopting steel bar sleeves 13 or welding, so that an electric path between the box culverts is formed.

Leading connecting reinforcing steel bars 12 are arranged at certain intervals along the longitudinal direction of the tunnel, and the leading connecting reinforcing steel bars and the annular grounding reinforcing steel bars 7 of the under-rail structure are welded firmly to form an electric path.

And after the cast-in-place side box culvert of the structure below the rail is poured, binding the reinforcing steel bars of the communication cable trough 5, and arranging the longitudinal grounding reinforcing steel bars 10 on the side wall of the communication cable trough 5.

The side wall and the bottom of the communication cable trough 5 are respectively embedded with a cable trough side wall grounding terminal 8 and a cable trough bottom grounding terminal 9 at certain intervals, and the grounding terminals 8 and 9 and the longitudinal grounding steel bars 10 of the side wall of the cable trough are respectively and firmly welded with the leading steel bars 12 to form an electric path.

And pouring the cast-in-place communication cable groove 5 of the structure under the rail, laying the through ground wire 11 at the bottom of the communication cable groove 5, and firmly welding the through ground wire 11 and the wiring terminal 9 to form an electric path and leading the electric path to the outside of the tunnel for grounding.

And sand protection is performed at the bottom of the communication cable groove 5.

The technical requirements for implementing the invention are as follows:

in box culvert and cast-in-place limit box culvert in the structure prefabrication under the tunnel rail to 1m is the interval, selects its longitudinal structure reinforcing bar as the longitudinal ground connection reinforcing bar 6 of structure under the rail.

Every operation section (length 2m, with shield structure section of jurisdiction per ring length the same, and every 2 ring canal pieces set up one department) of the longitudinal ground connection reinforcing bar of structure under the rail selects 2 to encircle the structural reinforcement as the circumferential ground connection reinforcing bar 7 of structure under the rail, and reliable welding between ring, longitudinal ground connection reinforcing bar to the circumferential ground connection reinforcing bar should be connected with two through earth wires 11 of both sides.

The annular grounding steel bars 7 of the under-rail structure in each operation section (2m) are connected with the longitudinal grounding steel bars 10 of the side edges of the cable troughs close to the line side of the communication cable troughs 5 at two sides through connecting steel bars 12.

The longitudinal grounding steel bars 10 (the diameter is not less than 16mm) of the side wall of the cable trough on the upper part of the side wall of the communication cable trough 5 are used as the longitudinal grounding steel bars of the side wall of the cable trough, the distance between the outer edges of the longitudinal grounding steel bars 10 of the side wall of the cable trough and the outer surface of the reinforced concrete is not less than 30mm, and the longitudinal grounding steel bars are disconnected once every 100 m.

The ground terminals all adopt bridge tunnel type ground terminals.

And one grounding terminal is arranged at every 100m interval at the bottom of the communication cable groove, so that the tunnel grounding device is connected with the through ground wire.

One ground terminal is provided at every 50m interval on the side wall of the communication cable trough.

All the ground terminals are connected with the cable trough side wall longitudinal ground reinforcing bars 10 through a16 lead-in reinforcing bars 12.

All the connections between the grounding steel bars are required to ensure the welding quality, the lap length of the single-side welding is not less than 10d, and the lap length of the double-side welding is not less than 5d, wherein d is the diameter of the steel bar. The cross point of the grounding steel bars is welded by an A16 steel bar L shape, and the welding length is the same as the requirement.

An a16 longitudinal earth wire 11 is laid inside the tunnel along the line in the communication cable trough 5 and is led to the ground outside the tunnel.

And taking sand protection measures at the bottom of the communication cable slot.

After the grounding project is finished, a resistance test is carried out, and the grounding requirement can be met by ensuring that the resistance is not more than 1 ohm.

Practice proves that the railway shield tunnel comprehensive grounding matching structure is simple in structure and convenient to implement, other grounding materials except the through ground wire and the grounding terminal are all embedded in a concrete structure and are not easy to corrode, the grounding materials are all taken from inherent structural steel bars, and special materials do not need to be additionally arranged, so that the purposes of accelerating the engineering progress, reducing the engineering investment, increasing the durability of a grounding system, reducing the failure rate and ensuring a good grounding effect can be achieved.

The 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 of the present invention, and the present invention is covered thereby. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.