CN107100644B - Longitudinal rigidity strengthening structure and construction method of subway shield tunnel - Google Patents

Abstract

The invention discloses a longitudinal rigidity reinforcing structure of a subway shield tunnel and a construction method thereof, wherein the reinforcing structure comprises a track plate and a plurality of longitudinal reinforced concrete beams, wherein the track plate and the plurality of longitudinal reinforced concrete beams are overlapped on the inner surface of the subway shield tunnel; the track slab and the longitudinal reinforced concrete beam are arranged along the axial direction of the subway shield tunnel, and reserved protruding reinforcing steel bars are uniformly distributed on the design overlapping surface of the inner wall of the duct piece of the subway shield tunnel so as to be connected with the track slab and the longitudinal reinforced concrete beam to form an overlapping combined structure. The invention has the advantages that the internal clearance of the shield tunnel is reasonably utilized, the connection between the subway shield tunnel and the cast-in-situ longitudinal reinforced concrete beam and the track slab is enhanced by reserving the protruding reinforcing steel bars on the duct piece, a composite structure with good superposition is formed, the longitudinal vertical bending rigidity, the horizontal bending rigidity, the longitudinal torsional rigidity and the transverse bending rigidity of the subway shield tunnel are greatly increased, and the longitudinal uneven deformation and the transverse elliptical deformation of the shield tunnel are reduced.

Description

Longitudinal rigidity strengthening structure and construction method of subway shield tunnel

technical field

The invention belongs to the field of rail transit, and in particular relates to a longitudinal rigidity strengthening structure of a subway shield tunnel and a construction method thereof.

Background technique

The shield tunnel is a slender tubular structure assembled from segments, and its longitudinal stiffness, bending stiffness, and torsional stiffness are relatively small. Therefore, uneven settlement, torsion, and horizontal deflection are prone to occur during subway operation. Shifting and other deformation and other problems, and thus lead to excessive opening of the segment joints of the shield tunnel, water leakage, and even damage to the segment joints, which in turn leads to fragmentation of the segment edges and plastic deformation of the threads of the connecting bolts, The connecting bolts are broken or sheared and other damages. The inner sides of the existing shield tunnel segments are all smooth surfaces. Although the track slab is a cast-in-place reinforced concrete slab with high longitudinal stiffness, when the shield tunnel undergoes deformations such as uneven settlement, torsion, and horizontal deviation, Not only can the track slab fail to play its role of high longitudinal stiffness, but also the gap between the track slab and the shield tunnel is prone to occur, and the vibration between the track slab and the tunnel is prone to occur under the action of the train load, and the damage of the tunnel and the track is accelerated . The engineering problems mentioned above are more likely to occur in shield tunnels in soft soil areas.

The cross-section of the existing shield tunnels generally adopts a circular structure. In order to make more reasonable use of the cross-sectional space or improve construction efficiency, there are also shield tunnels with other cross-sectional forms, such as transverse oval and quasi-rectangular (Ningbo Metro Line 3 Adopt), semicircle, horseshoe, double circle, three circle, etc. However, the subway boundary (the minimum effective cross-section after meeting the needs of subway vehicle operation, equipment installation, and pipeline installation) is close to a rectangle, so there is always an unusable internal clearance in the shield tunnel.

In addition, because the vertical water and soil pressure on the shield tunnel is greater than the horizontal water and soil pressure, this causes the cross section of the shield tunnel to be subjected to a large internal tensile bending moment at the top and a large bending moment at the bottom of the shield tunnel. Bending moment under tension on the outside, and thus cause the longitudinal seam joints between the segments to open, and even cause damage to the longitudinal seam joints and water leakage; this difference in water and soil pressure may also lead to a larger gap in the cross section of the shield tunnel. Large transverse elliptical deformations, especially in shield tunnels located in soft soil areas.

In order to solve the above-mentioned technologies, in some existing technologies, a layer of reinforced concrete with uniform thickness will be poured on the inner surface of the shield tunnel as the inner lining of the tunnel. This method can increase the stiffness of the shield tunnel to a certain extent, but the existing The reinforced concrete lining in the technology has the following technical problems:

1. The thickness of the reinforced concrete lining is uniform, which will greatly reduce the clearance available inside the shield tunnel; in the case of the reinforced concrete lining, in order to meet the boundary requirements of the subway, the diameter of the shield tunnel needs to be increased, so that Increase the engineering cost and reduce the lateral stiffness of the shield tunnel.

2. In the prior art, the reinforced concrete lining is mostly connected to the segment through the connecting steel bars welded on the segment connecting bolts. This connection method is too weak to bear the tensile force; in addition, the surrounding stress of the segment bolt holes is very complicated , The concrete around the bolt holes is easily damaged, and the practice in the prior art can easily lead to damage to the segment connecting bolt holes.

3. Reserve pits and protrusions between the segment and the cast-in-place lining, and their function is to resist shearing. When uneven settlement occurs in the shield tunnel, tension is likely to appear between the segment and the cast-in-place lining, so the reserved pits and protrusions cannot play a role.

Contents of the invention

The object of the present invention is to provide a kind of subway shield tunnel longitudinal rigidity strengthening structure and its construction method according to the deficiencies of the above-mentioned prior art. The structural stiffness of the shield tunnel.

The object of the present invention is realized by the following technical solutions:

A longitudinal stiffness strengthening structure of a subway shield tunnel, characterized in that: the longitudinal stiffness strengthening structure of the subway shield tunnel includes a track plate and several longitudinal reinforced concrete beams superimposed on the inner surface of the subway shield tunnel; the track The slab and the longitudinal reinforced concrete beams are all arranged along the axial direction of the subway shield tunnel, and reserved protruding steel bars are evenly distributed on the design superposition surface of the segment inner wall of the subway shield tunnel to match the track slab And the longitudinal reinforced concrete beams are connected to form a superimposed composite structure; the position and cross-sectional shape of the longitudinal reinforced concrete beams and the track slab conform to the internal clearance of the subway shield tunnel and the subway limit.

One end of the protruding steel bar is buried and connected to the intersection point of the main bar inside the segment, and the other end is buried in the inside of the longitudinal reinforced concrete beam or the track slab, and the protruding steel bar is connected to the longitudinal reinforced concrete beam or the track slab. The main reinforcement inside the track slab is connected; the distribution density of the protruding steel bars in the radial direction on the segment is 0.03-0.04㎡/root.

The longitudinal reinforced concrete beams are superimposed on the inner walls of both sides of the subway shield tunnel, and the longitudinal reinforced concrete beams on both sides and the track slabs form a "U"-shaped integrated structure.

The top of the subway shield tunnel is superimposed with the longitudinal reinforced concrete beam.

The track slab is made of reinforced concrete, and connecting steel bars are arranged between the track slab and the longitudinal reinforced concrete beams located at the sides of the subway shield tunnel.

The outer wall of the longitudinal reinforced concrete beam is in an arc shape matching the inner wall of the subway shield tunnel, and the inner surface is in a vertical plane or a horizontal plane.

A construction method for a longitudinal stiffness-reinforced structure of a subway shield tunnel, the construction method comprising the following steps: making a segment, and pre-burying a protrusion at the preset overlapping position of the segment, a track slab, and a longitudinal reinforced concrete beam protruding steel bars on the inner surface; assembling the segments into a subway shield tunnel; binding steel bars at preset positions of the longitudinal reinforced concrete beams and the track slab, and lapping the protruding steel bars on the segment Connecting; installing formwork; pouring the concrete of the track slab and the longitudinal reinforced concrete beam, and the track slab and the longitudinal reinforced concrete beam are close to the inner surface of the subway shield tunnel.

In the process of binding the steel bars, connecting steel bars are set between the steel bars of the concrete beams and the steel bars of the longitudinal reinforced concrete beams on the side of the subway shield tunnel; in the process of pouring concrete, the track slab The longitudinal reinforced concrete beam at the side of the subway shield tunnel is poured simultaneously, or the track slab is poured first and then the longitudinal reinforced concrete beam at the side of the subway shield tunnel is poured.

During the transportation and assembly construction process of the segments, the protruding steel bars on the segments are bent.

It is characterized in that the position and cross-sectional shape of the longitudinal reinforced concrete beam are determined according to the internal clearance of the shield tunnel and the limit of the subway.

The advantage of the present invention is that by reserving protruding steel bars on the segments, the connection between the subway shield tunnel and the cast-in-place longitudinal reinforced concrete beams and track slabs is strengthened to form a well-laminated combined structure, which greatly increases the number of subway shield tunnels. The longitudinal vertical bending stiffness, horizontal bending stiffness, and torsional stiffness of the shield tunnel can also strengthen the transverse bending stiffness of the subway shield tunnel, completely avoiding the separation between the track slab and the shield tunnel during the uneven settlement of the shield. Hollow phenomenon, while reducing the longitudinal uneven deformation of the shield tunnel, it also reduces the horizontal elliptical deformation of the subway shield tunnel.

Description of drawings

Fig. 1 is the cross-sectional schematic diagram of the subway shield tunnel in the embodiment 1 of the present invention;

Figure 2 is a side view I of the segment in Example 1 of the present invention;

Fig. 3 is a side view II of the segment in Example 1 of the present invention;

Fig. 4 is the schematic cross-sectional view of the subway shield tunnel in embodiment 2 of the present invention;

Fig. 5 is the schematic cross-sectional view of the subway shield tunnel in embodiment 3 of the present invention;

Fig. 6 is a schematic cross-sectional view of the subway shield tunnel in Embodiment 4 of the present invention;

Fig. 7 is a schematic cross-sectional view of the subway shield tunnel in Embodiment 5 of the present invention;

Fig. 8 is a schematic cross-sectional view of the subway shield tunnel in Embodiment 6 of the present invention.

Detailed ways

The features of the present invention and other relevant features are described in further detail below in conjunction with the accompanying drawings through the embodiments, so as to facilitate the understanding of those skilled in the art:

As shown in Figure 1-8, the marks 1-7 in the figure are: subway shield tunnel 1, track slab 2, longitudinal reinforced concrete beam 3, protruding steel bar 4, segment 5, longitudinal partition wall 6, and channel 7.

Embodiment 1: As shown in Figures 1 and 2, this embodiment specifically relates to a longitudinal stiffness reinforcement structure of a subway shield tunnel, which includes a track slab 2 arranged on the inner surface of a subway shield tunnel 1 and several longitudinal reinforced concrete beams 3. The subway shield tunnel 1 is assembled from several segments 5 made of reinforced concrete. The cross section of the subway shield tunnel 1 is circular; the track slab 2 and the longitudinal reinforced concrete beam 3 are along the axis of the subway shield tunnel 1 Setting, between the longitudinal reinforced concrete beam 3 and the track slab 2 and the segment 5 of the subway shield tunnel 1, there is a protruding steel bar 4 for connection; one end of the protruding steel bar 4 is buried inside the segment 5, and the other end is buried in the longitudinal Inside the reinforced concrete beam 3 or the track slab; the protruding steel bar 4 can effectively connect the track slab 2 and the longitudinal reinforced concrete beam 3 with the segments 5 of the subway shield tunnel 1 to form a superimposed composite structure.

As shown in Figures 1 and 2, the position and cross-sectional shape of the longitudinal reinforced concrete beam 3 and the track slab 2 are designed according to the internal clearance of the subway shield tunnel 1 and the boundary of the subway. When conditions permit, in this embodiment, the subway shield A longitudinal reinforced concrete beam 3 is superimposed on the top and both sides of the shield tunnel 1; the bottom edge of the longitudinal reinforced concrete beam 3 located on both sides of the subway shield tunnel 1 is respectively connected with the two sides of the track slab 2 to form a " U"-shaped overall structure, thereby forming an overall stable force-bearing structure; the track slab 2 is made of reinforced concrete, the steel cage in the track slab 2 and the steel bars of the longitudinal reinforced concrete beam 3 located on both sides of the subway shield tunnel 1 The cage is connected as a whole by connecting steel bars; the longitudinal rigidity of the longitudinal reinforced concrete beam 3 and the track slab 2 can be effectively enhanced by connecting the track slab 2 and the adjacent longitudinal reinforced concrete as a whole.

As shown in Figures 1 and 2, in this embodiment, the track slab 2 and the segments 5 of the subway shield tunnel 1 are connected to form a whole through protruding steel bars 4, forming a well-laminated combined structure, which can prevent the subway shield from During the deformation process of tunnel 1, such as uneven settlement, torsion and horizontal deviation, the track slab 2 is detached (empty).

As shown in Figures 1 and 2, in this embodiment, the length of each longitudinal reinforced concrete beam 3 is greater than the length of the segment 5, and the longitudinal reinforced concrete beam 3 and the track slab 2 connect the longitudinally arranged segments together to form a stack A well-combined structure can greatly increase the longitudinal vertical bending stiffness, horizontal bending stiffness, and torsional stiffness of the shield tunnel. At the same time, it can also strengthen the transverse bending stiffness of the shield tunnel and reduce the transverse elliptical deformation of the shield tunnel.

As shown in Figures 1 and 2, in the present embodiment, the track slab 2 and the longitudinal reinforced concrete beam 3 cover the longitudinal joints between the segments 5 of the subway shield tunnel 1, which makes the track slab 2 and the longitudinal reinforced concrete beam 3 The bending moment at the joint of the segment 5 can be shared, and the seam head of the longitudinal seam of the segment 5 is prevented from opening, thereby causing damage to the longitudinal seam of the segment and water leakage.

As shown in Figures 1 and 2, in this embodiment, the cross section of the longitudinal reinforced concrete beam 3 is determined according to the internal clearance of the shield tunnel and the boundary of the subway, that is, the outer wall of the longitudinal reinforced concrete beam 3 is suitable for the inner wall of the subway shield tunnel 1 The arc shape and the inner wall surface are in the shape of a vertical plane or a horizontal plane, so that the cross-section of the space formed by the track slab 2 and the longitudinal reinforced concrete beam 3 is a rectangular shape, and this cross-sectional shape makes the track slab 2 and the longitudinal reinforcement The concrete beam 3 can make full use of the clearance in the subway shield tunnel 1 and most effectively increase the longitudinal stiffness and lateral stiffness of the subway shield tunnel 1 .

As shown in Figures 1 and 2, in this embodiment, the protruding steel bars 4 located on the inner wall of the segment 5 are distributed at the overlapping positions of the segment 5, the longitudinal reinforced concrete beam 3 and the track slab 2; the distribution density of the protruding steel bars 4 is 0.03 m ² / root to 0.04m ² / root; the protruding steel bar 4 overlaps with the main bar in the track slab 2 or the main bar of the longitudinal reinforced concrete beam 3; the protruding length of the protruding steel bar 4 from the inner surface of the segment 5 depends on the The overlapping conditions of the steel bars of the track slab 2 and the steel bars of the longitudinal reinforced concrete beam 3 are determined; the protruding steel bars 4 make the connection between the track slab 2 and the longitudinal reinforced concrete beam 3 more reliable; through the connection of the protruding steel bars 4, the longitudinal reinforced concrete beam 3 Not only can the anti-shear force of the subway shield tunnel 1 be improved, but also the ability of the subway shield tunnel 1 to resist the tensile force can be effectively improved.

As shown in Figures 1 and 2, the construction method of the subway shield tunnel longitudinal stiffness strengthening structure of the present embodiment specifically includes the following steps:

1) As shown in Figures 2 and 3, the position and cross-sectional shape of the longitudinal reinforced concrete beam 3 and the track slab 2 are determined according to the internal clearance of the shield tunnel 1 and the subway limit, and the segment 5 is made of reinforced concrete, and the segment 5 is Embed protruding steel bars 4 radially at the predetermined overlapping positions of the track slab 2 and the longitudinal reinforced concrete beam 3, one end of the protruding steel bars 4 is buried inside the concrete of the segment 5, and the other end of the protruding steel bar 4 is embedded from the inner surface of the segment 5. protruding; the distribution density of the protruding steel bars 4 on the segment 5 is 0.03-0.04m ² / root, which should be arranged as evenly as possible, and the end of the protruding steel bars 4 located inside the segment 5 is mainly arranged at the intersection of the main bars of the segment; The length of the protruding steel bar 4 protruding from the surface of the segment 5 depends on the overlap with the steel bar of the longitudinal reinforced concrete beam 3 and the track slab 2. It should be noted that the specific length of the protruding steel bar 4 may have a certain deviation, or it may be completely consistent , depending on the actual situation, as shown in Figures 2 and 3.

2) As shown in Figures 2 and 3, before the segment 5 is transported, according to the transportation, assembly of the segment 5 and on-site, if the protruding steel bar 4 located on the inner wall of the segment 5 hinders the construction work, the reserved The protruding steel bars 4 are bent to facilitate related operations such as transportation and segment assembly.

3) As shown in Figures 1, 2, and 3, the segments 5 are assembled to form a subway shield tunnel 1 according to the design.

4) As shown in Figures 1 and 2, after the assembly of the subway shield tunnel 1 is completed, the steel bars are bound at the preset positions of the track slab 2 and the longitudinal reinforced concrete beam 3. During the binding process, the track slab 2 and the longitudinal reinforced concrete beam 3 are The steel bars are bound and connected with the protruding steel bars 4 on the inner surface of the segment 5, and at the same time, the steel bars of the track slab 2 are connected with the steel bars of the longitudinal reinforced concrete beam 3 located on the side of the subway shield tunnel 1 by using connecting steel bars.

5) As shown in Figures 1 and 2, the formwork is installed. The shape and structure of the formwork are determined by the shape of the molded longitudinal reinforced concrete beam 3, and the track slab 2 is located at the bottom, which can be poured directly without formwork.

6) As shown in Figures 1 and 2, the concrete for the track slab 2 and the longitudinal reinforced concrete beam 3 is poured after the steel bar binding is completed and the formwork is installed; the track slab 2 and the side of the subway shield tunnel 1 can be poured simultaneously during the pouring process Concrete for the longitudinal reinforced concrete beam 3; considering that when the combination of the track slab 2 and the longitudinal reinforced concrete beam 3 at the side forms a "U"-shaped structure, one pouring will easily cause the concrete to flow out from the top 2 of the track, and it can be considered to divide it into two Forming, that is, pouring the track slab 2 first, and pouring the longitudinal reinforced concrete beam 3 on the side of the subway shield tunnel 1 after the concrete pouring of the track slab 2 reaches a certain strength; in the process of pouring concrete, the track slab 2 and the The longitudinal reinforced concrete beams 3 on the side of the subway shield tunnel 1 are connected as a whole to form a U-shaped overall structure. When the steel bars of the poured longitudinal reinforced concrete beams 3 are connected, the concrete should be poured at the same time as possible when conditions permit. When not allowed, it can be poured in batches. It should be noted that all the steel bars of the longitudinal reinforced concrete beams 3 must be installed at the same time when they are connected to strengthen the connection between the longitudinal reinforced concrete beams 3; when there is no connection, they can be divided into different batches according to the convenience of construction Install for the first time, and allow the concrete of the previous batch of longitudinal reinforced concrete beams 3 to reach the design strength before installing the reinforcement bars of the next batch of longitudinal reinforced concrete beams 3.

7) Finally, remove the formwork when the concrete strength of the longitudinal reinforced concrete beam 4 reaches the allowable formwork removal strength.

The beneficial technical effect of this embodiment is: by reserving protruding steel bars on the segment, the connection between the subway shield tunnel and the cast-in-place longitudinal reinforced concrete beam and the track slab is strengthened to form a well-laminated combined structure, which greatly increases The longitudinal vertical bending stiffness, horizontal bending stiffness, and torsional stiffness of the subway shield tunnel are improved, and at the same time, the transverse bending stiffness of the subway shield tunnel can be strengthened, and the transverse elliptical deformation of the subway shield tunnel can be reduced.

Embodiment 2: As shown in Figure 4, the section of the subway shield tunnel 1 is circular in the present embodiment, and the main difference between the present embodiment and the embodiment 1 is the quantity and the shape of the longitudinal reinforced concrete beam 3; in the present embodiment The number of longitudinal reinforced concrete beams 3 is two, and the two longitudinal reinforced concrete beams 3 are arranged on both sides of the subway shield tunnel 1, and the two longitudinal reinforced concrete beams 3 are respectively connected to the two sides of the track slab 2, and the track slab 2 And the longitudinal reinforced concrete beam 3 constitutes a U-shaped inner lining structure.

Embodiment 3: As shown in Figure 5, the main difference between this embodiment and Embodiment 2 is the cross-sectional shape of the subway shield tunnel 1. In this embodiment, the cross-sectional shape of the subway shield tunnel 1 is the vertical egg shown in Figure 5 shape.

Embodiment 4: As shown in Figure 6, the main difference between this embodiment and Embodiment 1 is the cross-sectional shape of the subway shield tunnel 1. In this embodiment, the cross-sectional shape of the subway shield tunnel 1 is the vertical egg shown in Figure 6 shape.

Embodiment 5: As shown in Figure 7, the main difference between this embodiment and Embodiment 1 is the cross-sectional shape of the subway shield tunnel 1, and the cross-sectional shape of the subway shield tunnel 1 in this embodiment is the ellipse shown in Figure 7 .

Embodiment 6: As shown in Figure 8, the section of the subway shield tunnel 1 in this embodiment is a rectangular shape, and the interior of the subway shield tunnel 1 is provided with a longitudinal partition wall 6, which divides the subway shield tunnel 1 into two parts. channel 7; track slab 2 is arranged at the bottom of each channel 7, and longitudinal reinforced concrete beam 3 is arranged on the side wall opposite to channel 7 and longitudinal partition wall 6; track slab 2 and longitudinal reinforced concrete beam 3 are connected with subway The connection structure of the shield tunnel 1 is the same as that of the embodiment 1, but there is no connection structure between the track slab 2 and the longitudinal reinforced concrete beam 3 in this embodiment.

Claims (7)

1. A subway shield tunnel longitudinal rigidity reinforced structure which is characterized in that: the longitudinal rigidity reinforcing structure of the subway shield tunnel comprises a track plate and a plurality of longitudinal reinforced concrete beams, wherein the track plate is overlapped on the inner surface of the subway shield tunnel; the track plate and the longitudinal reinforced concrete beam are arranged along the axial direction of the subway shield tunnel, and reserved protruding steel bars are uniformly distributed on the design overlapping surface of the inner wall of the duct piece of the subway shield tunnel so as to be connected with the track plate and the longitudinal reinforced concrete beam to form an overlapped combined structure; the position and the section shape of the longitudinal reinforced concrete beam and the track plate conform to the internal clearance of the subway shield tunnel and the subway limit;

one end of the protruding reinforcing steel bar is embedded into a main reinforcement intersection point connected to the inside of the duct piece, the other end of the protruding reinforcing steel bar is embedded into the longitudinal reinforced concrete beam or the inside of the track slab, and the protruding reinforcing steel bar is connected with the main reinforcement inside the longitudinal reinforced concrete beam or the track slab; the distribution density of the radial protruding reinforcing steel bars on the duct piece is 0.03-0.04 square meter per square meter;

the longitudinal reinforced concrete beams are overlapped on the inner walls of the two sides in the subway shield tunnel, and the longitudinal reinforced concrete beams positioned on the two sides and the track slab form an integral structure in a U shape;

the track slab is made of reinforced concrete, and connecting steel bars are arranged between the track slab and the longitudinal reinforced concrete beams positioned on the side edges of the subway shield tunnel.

2. The subway shield tunnel longitudinal rigidity reinforcing structure according to claim 1, wherein: the top in the subway shield tunnel is overlapped and provided with the longitudinal reinforced concrete beam.

3. A subway shield tunnel longitudinal rigidity reinforcing structure according to claim 1 or 2, characterized in that: the outer wall of the longitudinal reinforced concrete beam is in an arc shape matched with the inner wall surface of the subway shield tunnel, and the inner side of the longitudinal reinforced concrete beam is in a vertical plane shape or a horizontal plane shape.

4. A construction method related to the longitudinal rigidity reinforcing structure of the subway shield tunnel according to any one of claims 1 to 3, characterized in that: the construction method comprises the following steps: manufacturing a duct piece, and embedding protruding reinforcing steel bars protruding out of the inner surface at preset overlapping positions of the duct piece, the track plate and the longitudinal reinforced concrete beam; assembling the segments into a subway shield tunnel; binding steel bars at preset positions of the longitudinal reinforced concrete beam and the track plate, and overlapping the protruding steel bars on the duct piece; installing a template; and pouring concrete of the track slab and the longitudinal reinforced concrete beam, wherein the track slab and the longitudinal reinforced concrete beam are tightly attached to the inner surface of the subway shield tunnel.

5. The construction method according to claim 4, wherein: in the process of binding the steel bars, connecting steel bars are arranged between the steel bars of the track plate and the steel bars of the longitudinal reinforced concrete beam positioned at the side edge of the subway shield tunnel; in the process of pouring concrete, the track slab and the longitudinal reinforced concrete beam at the side part of the subway shield tunnel are poured simultaneously, or the track slab is poured first and then the longitudinal reinforced concrete beam at the side part of the subway shield tunnel is poured.

6. The construction method according to claim 4, wherein: and bending the protruding reinforcing steel bars on the duct piece in the transportation and assembly construction process of the duct piece.

7. The construction method according to claim 4, wherein: and determining the position and the section shape of the longitudinal reinforced concrete beam according to the internal clearance of the shield tunnel and the subway limit.

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