CN116575940A - A Concrete Pouring Method for Shield Tunnel Door Ring Beam - Google Patents

Abstract

The invention discloses a concrete pouring method for a door ring beam of a shield tunnel. A concrete pouring conduit is pre-embedded in the side wall concrete above the door ring beam in a station as the only concrete pouring hole, and is separated from the vibrating hole to ensure continuous pouring of concrete; The vibrating bar guide channel is set at the waist of the door ring beam and above to effectively vibrate the concrete at the waist of the door ring beam and above; the concrete pouring conduit and the vibrator guide channel are separated from each other, and the concrete pouring and vibration can be operated at the same time . The invention can realize the separation of the pouring hole and the vibrating hole, ensure the continuous pouring of concrete, prevent concrete segregation, vibrate and compact the waist and top of the ring beam, greatly improve the quality of concrete pouring, and reduce the risk of water leakage; at the same time, the concrete pump truck is omitted , It can avoid the potential safety hazard caused by the impact force caused by the workers needing to support the pump pipe, and at the same time avoid the difficulty in coordination of the pump truck and the high cost of using the pump truck.

Description

A Concrete Pouring Method for Shield Tunnel Door Ring Beam

technical field

The invention belongs to the technical field of construction, and more specifically relates to a concrete pouring method for a portal ring beam in a shield section of a subway.

Background technique

Door ring beams need to be constructed at the connection between the two ends of the shield tunnel and the side wall of the subway station. The door ring beam is divided into two types: built-in type and external type. The built-in structure is common. The built-in door ring beam is flush with the concrete side wall, which is equivalent to being embedded in the side wall. The general embedded width is 400mm~800mm. Most of them are 600mm, and the thickness is greater than 500mm, so it is difficult to pour concrete. At present, the concrete pouring of the ring beam of the shield tunnel door is generally made by opening holes on the formwork from bottom to top when the formwork is installed, and 3 to 5 pouring holes are reserved, and the concrete pump truck has its own pump pipe to pour concrete against the pouring holes. At the same time, the pouring hole is often used as a concrete vibrating hole, which has the following defects:

(1) When pouring concrete, it is necessary to block the pouring holes intermittently. When the pouring holes are blocked, it is necessary to suspend the concrete pouring, resulting in the inability of continuous pouring of concrete, affecting the bonding quality between concrete, and causing water leakage, which is difficult to deal with;

(2) When pouring concrete, the pouring hole is often used as a vibrating hole, and the vibrating and pouring operations are alternated. The construction quality is not easy to control, resulting in insufficient vibration, water leakage often occurs, and the treatment is difficult;

(3) It is difficult to vibrate the concrete at the waist and above the ring beam of the portal, and often leaks vibration or does not vibrate properly, resulting in water leakage and difficult treatment;

(4) When the setting of pouring holes is insufficient, the height of concrete cutting in the door ring beam reinforcement exceeds 2m, which is prone to concrete segregation and poor flow, which affects the quality of concrete pouring;

(5) When pouring concrete, the operator must support the pump pipe on the support, but the impact force of the pump pipe is large, it is difficult for the operator to control it, and there are potential safety hazards;

(6) The amount of concrete required for the ring beam of the portal is small, the coordination of the pump truck is difficult, and the cost is high. At the same time, the remaining concrete in the pump pipe is wasted after the pouring is completed, resulting in higher costs.

Therefore, in order to ensure the construction quality and safety of the concrete pouring of the portal ring beam, it is necessary to research and invent new methods, overcome the deficiencies of the existing technologies, and improve the traditional methods.

Contents of the invention

Purpose of the invention: In view of the above technical problems, the present invention proposes a concrete pouring method for the ring beam of the portal, which can realize the separation of the pouring hole and the vibrating hole, ensure continuous pouring of concrete, prevent concrete segregation, and vibrate the waist and top of the ring beam densely, greatly Improve the quality of concrete pouring and reduce the risk of water leakage; at the same time, save the concrete pump truck, which can avoid potential safety hazards caused by the impact force caused by workers needing to support the pump pipe, and at the same time avoid the difficulty in coordination of pump trucks and the high cost of using pump trucks.

A method for pouring concrete for shield tunnel door ring beams, comprising the following steps:

S1. Making Concrete Pouring Conduits

The lower end of the concrete pouring conduit is set at the top of the middle of the door ring beam, and the upper end vertically passes through the side wall and extends to the top of the roof. In the lower part of the crown beam and the inner side of the retaining wall, the concrete pouring conduit is used as a concrete pouring channel;

S2. Pre-embedded vibrator guide channel

The vibrator guide channel includes:

The first vibrating rod guide channel is preset in the concrete pouring conduit, and is used for vibrating the concrete at the top of the portal ring beam from the bottom of the vibrating rod to the top of the portal ring beam;

The second vibrator guide channel is preset in the main reinforcement of the door ring beam skeleton and is located on both sides of the waist of the door ring beam, including a plurality of the second vibrator guide channels arranged vertically in parallel and at intervals;

The third vibrator guide channel is preset in the main reinforcement of the door ring beam skeleton and is located between the second vibrator guide channel and the top of the door ring beam, including a plurality of third vibrator guides The holes are evenly spaced and the hole axis of the third vibrating rod guide hole passes through the center of the door ring beam;

Both the second vibrator guide channel and the third vibrator guide channel include a steel pipe embedded in the wall and a round steel channel preset in the ring beam reinforcement;

S3. Install concrete feeding hopper and vibrator

When the door ring beam steel bars and formwork are installed and passed the inspection, the concrete feeding hopper and the vibrating rod are installed. The upper end of the concrete pouring conduit is docked and fixed, and the vibrating rod enters the top of the door ring beam from the feeding port of the feeding hopper along the first vibrating rod guide channel;

Throwing vibrating rods respectively through the second vibrating rod guide tunnel and the third vibrating rod guiding tunnel;

S4. Pouring concrete for the door ring beam and plugging the pouring conduit

Concrete flows into the ring beam of the portal through the pouring hopper through the concrete pouring conduit, and as the concrete surface in the ring beam of the portal rises, when there is concrete in the guide channel of the vibrating rod, the vibrating operation is started;

Concrete is poured all the way to the top of the concrete pouring conduit, and then the pouring is stopped to complete the plugging of the concrete pouring conduit.

The concrete pouring conduit is provided with a first buffer guide structure, and the first buffer guide structure is alternately arranged at upper and lower intervals along both sides of the inner wall of the concrete pouring conduit to buffer the concrete, prevent vertical segregation of the concrete below and guide Concrete flows in an orderly manner.

The first buffer guide structure is a V-shaped chute.

The waist of the door ring beam is provided with a second buffer guide structure, the second buffer guide structure is made of square steel plates, which are alternately arranged at intervals up and down along the door ring beam waist, the square steel plates are welded and fixed to the main reinforcement of the ring beam steel bar, and the second buffer guide structure The guide structure is used to buffer the falling speed of concrete, prevent vertical segregation of concrete, and guide the orderly flow of concrete.

The structure of the first vibrating bar guide channel and the round steel channel in the second vibrating bar guide channel are the same, both of which are made of round steel plus steel wires, at least 3 round steels are inside, and the steel wires are wound outside the round steel. Form a straight cylindrical spiral channel, the inner diameter of which is 40mm~50mm larger than the outer diameter of the vibrating rod;

The round steel channel in the guide channel of the third vibrating rod is bell-shaped, and the outer stirrup is wound with a steel wire ring with a spacing of 100 mm. There are no less than three skeleton main reinforcements in it made of round steel, and the distance between adjacent skeleton main reinforcements is Smaller than the diameter of the vibrating rod, the main reinforcement of the skeleton is bound and fixed with the spiral stirrup, and the main reinforcement of the skeleton is welded and fixed with the concrete pouring conduit and the second guide plate.

When the vertical distance between the ground and the roof of the station is less than 2m, the concrete tanker on the ground directly pours concrete into the discharge hopper;

When the vertical distance between the ground and the roof of the station exceeds 2m, use a chute or string to put concrete into the lower hopper to prevent concrete segregation.

The inner and outer walls of the concrete pouring conduit are treated with anti-rust paint. When the concrete pouring conduit is pre-buried, the top and bottom of the pipe are temporarily blocked, and the temporary seal is opened before the concrete pouring of the door ring beam.

The concrete pouring conduit is a square conduit with a section side length of 300 mm to 400 mm;

The first buffer guide structure is a triangular plate, a plurality of triangular plates are alternately arranged up and down on the inner wall of the concrete pouring conduit along the height direction, and the height distance between two adjacent triangular plates is less than 2m, and they are welded on the square concrete pouring The inner wall of the conduit, the angle between the first buffer guide structure and the inner wall of the concrete pouring conduit is 45°.

Beneficial effect

(1) A concrete pouring method for the door ring beam of the present invention. Since the concrete pouring conduit is pre-buried in the wall and outside the top of the door ring beam, the interruption of the pouring hole is avoided, and the concrete is continuously poured to ensure the quality of the continuous pouring of the concrete , reduce the risk of water leakage;

(2) A concrete pouring method for the door ring beam of the present invention, the concrete pouring hole is no longer used as a vibrating hole, the vibrating hole is set separately, and the concrete vibrating and pouring work at the same time, which is conducive to the concrete vibrating and compacting, and reduces the leakage of water risk;

(3) A method for concrete pouring of the door ring beam of the present invention, the first buffer guide plate is arranged in the pouring conduit, and the second buffer guide plate is arranged at the waist of the door ring beam, which prevents the concrete from falling vertically and segregates, which is conducive to the orderly flow of concrete, and has Conducive to the quality control of concrete pouring;

(4) A concrete pouring method for the door ring beam of the present invention, the second vibrator guide channel is set in the wall above the waist of the door ring beam and the third vibrator guide channel is set in the steel bar of the upper half of the ring beam, which is beneficial to Vibrate concrete to reduce the risk of water leakage;

(5) A concrete pouring method for the door ring beam of the present invention, the concrete tank truck is directly discharged on the ground, which can save the setting of the high-altitude concrete pouring platform, reduce the high-altitude operation, and avoid the risk of the high-altitude operation;

(6) A concrete pouring method for the door ring beam of the present invention saves the use of concrete pump trucks, avoids potential safety hazards caused by impact forces caused by workers needing to support the pump pipes, and avoids difficulties in coordination of pump trucks and high costs caused by the use of pump trucks.

Description of drawings

Fig. 1 is the vertical view of the overall structure of the door ring beam of the subway station side wall pouring of the present invention;

Among them, 1 is the ground; 2 is the retaining wall; 3 is the crown beam; 4 is the feeding hopper; 5 is the roof beam; 6 is the concrete pouring conduit; 7 is the middle plate beam; 10 is the guide channel of the second vibrator; 11 is the second buffer guide structure; 12 is the door ring beam; 13 is the underground pile or mast; 14 is the side wall of the station structure; 15 is the station structural side walls;

Fig. 2 is the sectional view of the overall structure of the door ring beam of the subway station side wall pouring of the present invention;

Among them, 16 are shield segments;

Fig. 3 is a schematic diagram of the second buffer guide structure arranged at the waist of the door ring beam;

Fig. 4 is the 3-3 direction view of Fig. 3;

Fig. 5 is the structural representation of concrete pouring conduit;

Fig. 6 is the 2-2 direction view of Fig. 5;

Fig. 7 is a structural schematic diagram of the first vibrator guide channel and the second vibrator guide channel;

Fig. 8 is a transverse sectional view of Fig. 7;

Wherein, 17 is the main reinforcement of the first skeleton; 18 is a straight cylindrical spiral steel wire stirrup;

Fig. 9 is a schematic structural view of the second vibrating rod guide channel;

Fig. 10 is a transverse sectional view of Fig. 9;

Wherein, 19 is the main reinforcement of the second skeleton; 20 is the trumpet-shaped spiral steel wire stirrup;

Fig. 11 is a schematic diagram of the channel structure communicating with the second vibrator guide channel and the third vibrator guide channel in the wall above the door ring beam;

Among them, 21 is a round steel channel; 22 is the wall around the door ring beam.

Detailed ways

The technical solution of the present invention will be described in further detail below in conjunction with specific embodiments and the accompanying drawings.

The invention provides a concrete pouring method for a ring beam of a shield tunnel door. The technical solution adopted is to pre-embed the concrete pouring conduit in the side wall concrete above the door ring beam in the station as the only concrete pouring hole, and separate it from the vibrating hole to ensure continuous pouring of concrete; The vibrator guide channel is set to effectively vibrate the concrete at the waist of the door ring beam and above; the concrete pouring conduit and the vibrator guide channel are separated from each other, and the concrete pouring and vibration can be operated at the same time, which is conducive to the continuous vibration of concrete.

The vibrator guide channel includes:

The first vibrator guide channel 8 is preset in the concrete pouring conduit 6, and is used for vibrating the concrete at the top of the door ring beam from the bottom of the vibrator to the top of the door ring beam;

The second vibrator guide channel 10 is preset in the main reinforcement of the door ring beam skeleton and is located on both sides of the waist of the door ring beam, including a plurality of the second vibrator guide channels vertically parallel and spaced ;

The third vibrator guide channel 9 is preset in the main reinforcement of the door ring beam skeleton and is located between the second vibrator guide channel and the top of the door ring beam, including multiple, multiple third vibrator The guide holes are evenly spaced and the hole axis of the third vibrator guide hole passes through the center of the door ring beam;

A round steel channel 21 communicating with the third vibrator guide tunnel 9 and the second vibrator guide tunnel 10 is provided in the wall above the door ring beam.

A method for concrete pouring of shield tunnel door ring beam concrete in the present invention, specifically comprises the following steps:

S1. Making Concrete Pouring Conduits

The lower end of the concrete pouring conduit is set at the top of the middle of the door ring beam, and the upper end vertically passes through the side wall and extends to the top of the roof. In the lower part of the crown beam and the inner side of the retaining wall, the concrete pouring conduit is used as a concrete pouring channel;

S2. Pre-embedded vibrator guide channel

The vibrator guide channel includes:

The first vibrating rod guide channel is preset in the concrete pouring conduit, and is used for vibrating the concrete at the top of the portal ring beam from the bottom of the vibrating rod to the top of the portal ring beam;

The second vibrator guide channel 10 is preset in the main reinforcement of the door ring beam skeleton and is located on both sides of the waist of the door ring beam, including a plurality of the second vibrator guide channels vertically parallel and spaced ;

The third vibrator guide channel 9 is preset in the main reinforcement of the door ring beam skeleton and is located between the second vibrator guide channel and the top of the door ring beam, including multiple, multiple third vibrator The guide holes are evenly spaced and the hole axis of the third vibrator guide hole passes through the center of the door ring beam;

Both the second vibrator guide channel and the third vibrator guide channel include a steel pipe embedded in the wall and a round steel channel preset in the ring beam reinforcement;

S3. Install concrete feeding hopper and vibrator

When the door ring beam steel bars and formwork are installed and passed the inspection, the concrete feeding hopper and the vibrating rod are installed. The upper end of the concrete pouring conduit is docked and fixed, and the vibrating rod enters the top of the door ring beam from the feeding port of the feeding hopper along the first vibrating rod guide channel;

Throwing vibrating rods respectively through the second vibrating rod guide tunnel and the third vibrating rod guiding tunnel;

S4. Pouring concrete for the door ring beam and plugging the pouring conduit

Concrete flows into the ring beam of the portal through the feeding hopper and the concrete pouring conduit. As the concrete surface in the ring beam of the portal rises, when there is concrete in the guide channel of the vibrating rod, the vibrating operation is started. A vibrator is inserted into the hole on the beam template to vibrate, and the upper half ring of the door ring beam is vibrated by inserting a vibrator from the third vibrator guide channel;

The left and right sides of the waist of the door ring beam are vibrated by inserting the vibrating rod from the second vibrating rod guide channel;

When the concrete surface rises to the top of the door ring beam, vibrate with a vibrator dropped from the first vibrator guide channel;

Concrete is poured all the way to the top of the concrete pouring conduit, and then the pouring is stopped to complete the plugging of the concrete pouring conduit.

As a preferred embodiment of the technical solution of the present invention, the first buffer guide structure is arranged inside the concrete pouring conduit, and the first buffer guide structure is alternately arranged at upper and lower intervals along both sides of the inner wall of the concrete pouring conduit for Buffer concrete, prevent concrete from segregating vertically below and guide concrete to flow in an orderly manner. The first buffer guide structure is a V-shaped chute.

As a preferred embodiment of the technical solution of the present invention, the waist of the door ring beam is provided with a second buffer guide structure, and the second buffer guide structure is alternately arranged up and down along the waist of the door ring beam, using square steel plates, square steel plates and rings The main reinforcement of the beam reinforcement is welded and fixed, and the second buffer guide structure is used to buffer the falling speed of concrete, prevent vertical segregation of concrete, and guide the orderly flow of concrete.

As a preferred embodiment of the technical solution of the present invention, the concrete pouring conduit is a square conduit with a side length of 300 mm to 400 mm in section; Alternately arranged up and down in the height direction, the height distance between two adjacent triangular plates is less than 2m, and welded to the inner wall of the square concrete pouring duct, the angle between the first buffer guide structure and the inner wall of the concrete pouring duct is 45°.

The concrete pouring conduit of the present invention adopts a square shape, because the square pipe is easier to process than the round pipe, the round pipe needs to be cut, the first buffer guide structure is connected with the round pipe in an arc shape, and it is difficult to process and weld, but the square pipe can be made of steel plate or thin-walled angle steel It is also convenient to manufacture and weld the built-in first buffer guide structure, so it is considered to use a square shape.

The first buffer guide structure uses a V-shaped chute, which is more conducive to the falling of concrete than a straight chute.

The concrete pouring conduit of the present invention has a built-in guide hole for the first vibrating rod, which is made of round steel, which is conducive to the up and down movement of the vibrating rod, and the distance between the main ribs of adjacent skeletons is smaller than the diameter of the vibrating rod, so as to prevent the vibrating rod from moving up and down or vibrating. The rod ran out of the guide hole of the vibrating rod, stuck the vibrating rod, etc. When pouring the square conduit to block the concrete, the vibrating rod vibrates in the guide channel, and the surrounding concrete is compacted by vibrating the concrete.

The structure of the first vibrating bar guide channel and the round steel channel in the second vibrating bar guide channel are the same, both of which are made of round steel plus steel wires, at least 3 round steels are inside, and the steel wires are wound outside the round steel. Form a straight cylindrical spiral channel, the inner diameter of which is 40mm~50mm larger than the outer diameter of the vibrating rod;

The round steel channel in the guide channel of the third vibrating rod is bell-shaped, and the outer stirrup is wound with a steel wire ring with a spacing of 100 mm. There are no less than three skeleton main reinforcements in it made of round steel, and the distance between adjacent skeleton main reinforcements is Smaller than the diameter of the vibrating rod, the main reinforcement of the skeleton is bound and fixed with the spiral stirrup, and the main reinforcement of the skeleton is welded and fixed with the concrete pouring conduit and the second guide plate.

Further, when the vertical distance between the ground and the roof of the station is less than 2m, the ground concrete tanker directly puts concrete into the discharge hopper; Concrete is placed in the hopper to prevent concrete segregation.

As a preferred embodiment of the technical solution of the present invention, the inner and outer walls of the concrete pouring conduit are treated with antirust paint, and when the concrete pouring conduit is pre-buried, the top and bottom of the pipe are temporarily blocked, and before the concrete pouring of the door ring beam, Open the temporary block.

Using the concrete pouring method for the shield door ring beam of the present invention, the lowering hopper is directly installed above the concrete pouring conduit, and the concrete tank truck can directly discharge the material into the hopper, which saves the use of concrete pump trucks and avoids the difficulties caused by the difficulty in controlling the pump pipe on the platform for workers. Safety risk, to avoid the cost of pump truck.

Claims (8)

1. The concrete pouring method for the shield tunnel portal ring beam is characterized by comprising the following steps of:

s1, manufacturing a concrete pouring guide pipe

The lower end of the concrete pouring guide pipe is arranged at the middle top of the portal ring beam, the upper end vertically upwards penetrates through the side wall and extends to the top of the top plate, and the concrete pouring guide pipe is used as a concrete pouring channel in the lower part of the inner side surfaces of the crown beam and the retaining wall;

s2, pre-buried vibrating rod guide pore canal

The vibrating rod guide duct comprises:

the first vibrating rod guide pore canal is preset in the concrete pouring guide pipe and is used for vibrating the concrete at the top of the portal ring beam from the lower part of the vibrating rod to the top of the portal ring beam;

the second vibrating rod guide pore canals are preset in the main ribs of the portal ring beam framework and are positioned at two sides of the waist of the portal ring beam, and the second vibrating rod guide pore canals are vertically and parallelly arranged at intervals;

the third vibrating rod guide pore canals are preset in the main ribs of the portal ring beam framework and are positioned between the second vibrating rod guide pore canals and the top of the portal ring beam, and the third vibrating rod guide pore canals comprise a plurality of third vibrating rod guide pore canals which are uniformly arranged at intervals, and the pore axes of the third vibrating rod guide pore canals penetrate through the circle center of the portal ring beam;

the second vibrating rod guide pore canal and the third vibrating rod guide pore canal both comprise a pre-embedded steel pipe in the secondary wall body and a steel channel preset in the ring beam steel bar;

s3, mounting a concrete blanking hopper and a vibrating rod

When the installation of the reinforcing steel bars and the templates of the portal ring beam is completed and the reinforcing steel bars and the templates pass through inspection and acceptance, installing a concrete blanking hopper and a vibrating rod, firstly installing the blanking hopper, and then installing the vibrating rod, wherein the blanking opening of the concrete blanking hopper is fixedly in butt joint with the upper end of a concrete pouring guide pipe at the top plate, and the vibrating rod enters the top of the portal ring beam from the blanking opening of the blanking hopper along a first vibrating rod guide pore channel;

respectively putting vibrating rods through the second vibrating rod guide pore canal and the third vibrating rod guide pore canal;

s4, pouring portal ring beam concrete and plugging pouring guide pipe

Concrete flows into the portal ring beam through the concrete pouring guide pipe through the blanking hopper, and rises along with the concrete surface in the portal ring beam, and when the concrete exists in the vibrating rod guide pore canal, vibrating operation is started;

and (5) pouring concrete until the top opening of the concrete pouring conduit is reached, and stopping pouring the concrete pouring conduit to complete the plugging of the concrete pouring conduit.

2. The method for pouring concrete into a shield tunnel portal beam according to claim 1, wherein a first buffer guiding structure is arranged in the concrete pouring conduit, and the first buffer guiding structure is alternately arranged at intervals of up and down along two sides of the inner wall of the concrete pouring conduit, so as to buffer the concrete, prevent the concrete from being isolated vertically below and guide the concrete to flow orderly.

3. The method for pouring concrete into a shield tunnel portal beam according to claim 2, wherein the first buffer guiding structure is a V-shaped chute.

4. The method for pouring the concrete of the ring beam of the shield tunnel portal according to claim 2, wherein the waist of the ring beam of the tunnel portal is provided with a second buffer guide structure, the second buffer guide structure adopts square steel plates which are alternately arranged up and down along the waist of the ring beam of the tunnel portal at intervals, the square steel plates are welded and fixed with the main bars of the ring beam steel bars, and the second buffer guide structure is used for buffering the falling speed of the concrete, preventing the concrete from falling vertically and segregating and guiding the concrete to flow orderly.

5. The concrete pouring method for the shield tunnel portal beam according to claim 3, wherein the round steel channel structures in the first vibrating rod guide channel and the second vibrating rod guide channel are the same, and are made of round steel and steel wires, at least 3 round steel wires are arranged inside the round steel wires, and the steel wires are wound outside the round steel wires to form a spiral channel, and the inner diameter of the spiral channel is 40 mm-50 mm larger than the outer diameter of the vibrating rod;

the round steel channel in the third vibrating rod guide pore canal is bell mouth-shaped, the outer stirrups of the third vibrating rod guide pore canal are wound by adopting steel wire rings, the distance is 100mm, at least 3 framework main ribs in the third vibrating rod guide pore canal are made of round steel, the distance between adjacent framework main ribs is smaller than the diameter of the vibrating rod, the framework main ribs are fixedly bound with spiral stirrups, and the framework main ribs are fixedly welded with a concrete pouring guide pipe and a second guide plate.

6. The method for pouring concrete of a shield tunnel portal beam according to claim 1, wherein,

when the vertical distance between the ground and the top plate of the station is less than 2m, the ground concrete tank truck directly puts concrete into the discharging hopper;

when the vertical distance between the ground and the top plate of the station exceeds 2m, concrete is put into the discharging hopper by adopting a chute or a serial cylinder so as to prevent the concrete from segregating.

7. The method for pouring concrete of the shield tunnel portal ring beam according to claim 1, wherein the inner wall and the outer wall of the concrete pouring conduit are treated by adopting antirust paint, temporary plugging is carried out on the top and the bottom of the conduit when the concrete pouring conduit is pre-buried, and the temporary plugging is opened before the tunnel portal ring beam is poured.

8. The method for pouring concrete of a shield tunnel portal beam according to claim 2, wherein,

the concrete pouring guide pipe is a square guide pipe with the section side length of 300-400 mm;

the first buffering guide structure is a triangular plate, a plurality of triangular plates are alternately arranged on the inner wall of the concrete pouring guide pipe along the height direction up and down, the height distance between every two adjacent triangular plates is smaller than 2m, the triangular plates are welded on the inner wall of the square concrete pouring guide pipe, and an included angle between the first buffering guide structure and the inner wall of the concrete pouring guide pipe is 45 degrees.