Single-layer shield tunnel full precast lane slab system and its construction method

Abstract

The present invention discloses a fully precast lane slab system for a single-layer shield tunnel and a construction method. The lane slab system includes shield segments, and wing-shaped L-shaped members are sequentially arranged inside the shield segments along the length direction of the shield segments; post-cast strips are respectively arranged on both sides of each wing-shaped L-shaped member; the construction method includes first precasting a plurality of wing-shaped L-shaped members, and then sequentially installing the precast wing-shaped L-shaped members in the shield segments, and connecting the top plates of a plurality of adjacent wing-shaped L-shaped members through connectors; after the tunnel settlement is stable, post-cast strips are respectively cast on both sides of each cast wing-shaped L-shaped member; on the premise of effectively ensuring the integrity of the lane slab system, the present invention cancels the setting of conventional cast-in-place corbels or arc plates, which is convenient for assembly construction; rapid construction can be realized and the workload on site can be reduced, thereby shortening the construction period and improving the efficiency. At the same time, the requirements for assembly accuracy are relatively low, and the interference from the misalignment and deformation of the shield segments and the internal structure is small.

Description

Technical Field

[0001] The present invention relates to the technical field of shield tunnel construction, and particularly to a fully precast lane slab system for a single-layer shield tunnel and a construction method thereof. Background Art

[0002] In recent years, with the in-depth promotion of infrastructure construction, tunnels have gradually expanded and extended from the urban central area to the surrounding undeveloped areas. Among them, the shield method is applicable to various soft strata. Due to its advantages of having little impact on ground traffic, buildings, rivers, shipping, etc., and being safe and efficient, it has become the mainstream method for constructing tunnels under the urban central area and crossing rivers and seas.

[0003] The internal structure of the shield divides the shield space and determines the overall function of the shield. The traditional internal structure of the shield has a high in-situ casting ratio, but it is difficult to meet the goal of efficient and green construction. In recent years, the internal structure of the shield has gradually changed to a precast assembly, in-situ casting, and a combination of precast assembly and in-situ casting. However, due to limitations such as the narrow space inside the shield, the overall prefabrication rate is relatively low. The current mainstream internal structure lane slab system assembly technology for single-layer shield tunnels and its disadvantages are as follows:

[0004] 1. The structure form of precasting a "mouth" - shaped member in the middle and casting the lane slabs on both sides in-situ. The connection between the in-situ cast lane slab and the segment is realized through in-situ cast corbels or arc linings. Formwork support and removal are required in the narrow arc surface space on both sides of the "mouth" - shaped member, resulting in a long construction period and consuming a large amount of formwork.

[0005] 2. The simply supported structure form of precasting a "mouth" - shaped member in the middle and precasting the slabs on both sides. Generally, in-situ cast corbels are required on both sides of the segment. It has disadvantages such as many lane slab joints, cumbersome joint treatment, poor integrity, etc., and diseases such as pavement cracking are caused under the action of vehicle vibration and temperature stress.

[0006] 3. Some projects have tried to cancel the in-situ cast corbels and fully precast the internal structure for assembly: For example, in the Tsinghua Yuan Tunnel, 1 middle "mouth" - shaped member and 2 side arc "mouth" - shaped members are assembled, and bolts are used to connect the "mouth" - shaped members; for example, the lower part of the shield of the Shanghai Airport Link uses a fully precast installation of an arc-shaped member with a triple-arch type. However, there are disadvantages such as great construction operation difficulty, high assembly accuracy requirements, and factors such as assembly errors, deformations, and offsets of the segments and the internal structure will cause great difficulties for subsequent assembly, and even lead to unevenness of the top pavement after assembly. Since it is difficult to ensure the density of the grouting filling between the internal structure and the segment, deformation may occur under the action of vehicle vibration during the later operation, and then pavement cracking may occur.

[0007] Therefore, how to effectively ensure the integrity of the lane slab system, cancel the conventional time-consuming in-situ cast corbels or arc plates, thereby shortening the construction period and improving efficiency, and at the same time being less affected by the offsets and deformations of the segments and the internal structure, and requiring relatively low assembly accuracy has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0008] In view of the above defects of the prior art, the technical object of the present invention is to provide a fully precast lane slab system and construction method for a single-layer shield tunnel, which, on the basis of ensuring the integrity of the lane slab system and eliminating conventional cast-in-place corbels or arc-shaped slabs, combines precast assembly technology to achieve the purpose of shortening the construction period and improving efficiency, while reducing the requirements for the control of assembly accuracy and making it less susceptible to the influence of the misalignment and deformation of the segment and the internal structure.

[0009] To achieve the above technical object, the present invention provides a fully precast lane slab system for a single-layer shield tunnel, including shield segments. Inside the shield segments and along the length direction of the shield segments, winged-shaped members are sequentially arranged. The two cantilever sections on both sides of several of the winged-shaped members adopt variable cross-section slabs; the ring width of the winged-shaped members is the same as the ring width of the shield segments.

[0010] A post-cast strip is respectively arranged on both sides of each of the winged-shaped members, and two post-cast strips on both sides of each winged-shaped member form a group; a post-cast beam is arranged at intervals of the joints between several groups of the post-cast strips and the shield segments.

[0011] Anti-collision structures are respectively arranged on both sides of the top of each of the winged-shaped members, and a road surface is laid in the area between the anti-collision structures on the tops of several of the winged-shaped members.

[0012] Preferably, several of the winged-shaped members are connected into a whole through connecting members.

[0013] Preferably, the two cantilever sections on both sides of several of the winged-shaped members adopt variable cross-section slabs. The overhanging lengths of the two wings of the winged-shaped members should be determined according to factors such as the passing vehicles and the self-weight of the winged-shaped members to avoid the overturning and damage of the lane slab system caused by the eccentric load of the vehicles during the operation stage.

[0014] Preferably, the top plate of the winged-shaped member is set as a solid structure or a hollow structure.

[0015] Preferably, the post-cast beam is arranged at intervals of 1 to 4 rings of the winged-shaped members for each group of the post-cast strips.

[0016] Preferably, the winged-shaped member is composed of a box-shaped member in the shape of a Chinese character "kou" and wing plates respectively arranged on both sides of the box-shaped member in the shape of a Chinese character "kou", and the box-shaped member in the shape of a Chinese character "kou" and the wing plates are of an integral structure.

[0017] Preferably, the width of the box-shaped member in the shape of a Chinese character "kou" along the length direction of the shield segment is greater than the width of the wing plates along the length direction of the shield segment.

[0018] A construction method for the fully precast lane slab system of the shield tunnel is also provided, including the following steps:

[0019] Step 1: First, prefabricate several winged "kou" shaped components, and then successively install the prefabricated winged "kou" shaped components inside the shield segment. The top plates of several winged "kou" shaped components are connected through connectors;

[0020] Step 2: After the tunnel settlement stabilizes, cast post-cast belts on both sides of each cast winged "kou" shaped component; after the post-cast belt construction is completed, cast post-cast beams at the joints between the post-cast belt and the shield segment every 1 to 4 rings of winged "kou" shaped components;

[0021] Step 3: Finally, install prefabricated anti-collision structures or cast in-situ anti-collision structures on both sides of the top of the winged "kou" shaped component, and then complete the road surface construction subsequently.

[0022] Preferably, when prefabricating the winged "kou" shaped component in Step 1, installation embedded parts for installing temporary railings are reserved on the top plate of the winged "kou" shaped component, and the temporary railings are installed after the installation of the winged "kou" shaped component is completed.

[0023] Preferably, after the tunnel settlement stabilizes in Step 2, both sides of several winged "kou" shaped components are connected through anchor bolts to form an integral whole.

[0024] Preferably, before pouring the post-cast belt in Step 2, horizontal main reinforcement bars are placed in the post-cast belt; and before the construction of the post-cast beam, reinforcement bars are planted on the shield segment; then the horizontal main reinforcement bars are connected to the planted reinforcement bars, and finally the post-cast beam and the post-cast belt are poured.

[0025] Advantages of the present invention:

[0026] The single-layer shield tunnel full precast lane slab system of the present invention, on the premise of effectively ensuring the integrity of the lane slab system, cancels the setting of conventional cast-in-situ corbels or arc plates, has a relatively simple overall structure, fast construction speed, and is convenient for assembly construction.

[0027] The construction method of the single-layer shield tunnel full precast lane slab system of the present invention, due to the relatively simple overall structure combined with the precast assembly technology, can achieve fast construction and reduce the on-site workload, thereby shortening the construction period. At the same time, the assembly accuracy requirements are relatively low, and it is less affected by the misalignment and deformation of the shield segment and the internal structure. Description of the drawings

[0028] Figure 1 It is a front view structural schematic diagram of the single-layer shield tunnel full precast lane slab system of the present invention;

[0029] Figure 2 It is a top view structural schematic diagram of the single-layer shield tunnel full precast lane slab system of the present invention;

[0030] Figure 3 It is a top view structural schematic diagram of the winged "kou" shaped component in the single-layer shield tunnel full precast lane slab system of the present invention;

[0031] Figure 4 This is a schematic diagram of the post-cast strip in the full precast lane slab system of the single-layer shield tunnel of the present invention;

[0032] Figure 5 This is a schematic diagram of installing the winged cross-shaped member in the construction method of the full precast lane slab system of the single-layer shield tunnel of the present invention;

[0033] Figure 6 This is a schematic diagram of constructing the post-cast beam in the construction method of the full precast lane slab system of the single-layer shield tunnel of the present invention.

[0034] In the figure: 1 shield segment, 2 winged cross-shaped member, 21 cross-shaped box body, 22 wing plate, 3 temporary railing, 4 post-cast beam, 5 post-cast strip, 6 anti-collision structure, 7 road surface. Specific embodiments

[0035] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the drawings to fully understand the purpose, features and effects of the present invention.

[0036] Example:

[0037] As Figures 1-4 shown, the full precast lane slab system of the single-layer shield tunnel includes a shield segment 1. Inside the shield segment 1 and along the length direction of the shield segment 1, winged cross-shaped members 2 are sequentially arranged; the overhanging sections on both sides of several of the winged cross-shaped members 2 adopt variable cross-section plates; post-cast strips 5 are respectively arranged on both sides of each winged cross-shaped member 2, and two post-cast strips 5 on both sides of each winged cross-shaped member 2 form a group; post-cast beams 4 are arranged at intervals in the joints between several groups of post-cast strips 5 and the shield segment 1; anti-collision structures 6 are respectively arranged on both sides of the top of each winged cross-shaped member 2, and road surfaces 7 are laid in the areas between the anti-collision structures 6 on the tops of several winged cross-shaped members 2.

[0038] More specifically, the top plates of several winged cross-shaped members 2 are connected into a whole through connecting members such as bolts and shear pins.

[0039] The top plate of the winged cross-shaped member 2 can be set as a solid structure or a hollow structure. When the hollow structure is adopted, the self-weight of the precast winged cross-shaped member 2 can be reduced, the amount of concrete used can be reduced, and thus carbon emissions can be reduced.

[0040] A post-cast beam 4 is arranged every 1 to 4 rings of winged cross-shaped members 2 for each group of post-cast strips 5 to strengthen the connection between the winged cross-shaped member 2 and the shield segment 1 and enhance the stability of the lane slab system.

[0041] The longitudinal spacing of the post-cast beams 4 should be adjusted according to the actual situation.

[0042] The winged square-shaped member 2 is composed of a square-shaped box body 21 and wing plates 22 respectively arranged on both sides of the square-shaped box body 21. The square-shaped box body 21 and the wing plates 22 are of an integral structure. The overhanging length L of the wing plates 22 should be determined according to factors such as the actual passing vehicles and the self-weight of the winged square-shaped member 2, and should not be too large to avoid the overturning and damage of the lane slab system caused by vehicle eccentric load during the operation stage.

[0043] To adapt to the deformation interference of the shield segment 1 and the internal structure misalignment, and reduce the requirements for the control of the assembly accuracy and accelerate the construction efficiency, the width of the square-shaped box body 21 along the length direction of the shield segment 1 is greater than the width of the wing plates 22 along the length direction of the shield segment 1.

[0044] As Figures 5-6 shown, the construction method of the above shield tunnel fully precast lane slab system specifically includes the following steps:

[0045] Step 1: First, precast a number of winged square-shaped members 2, and then sequentially install the precast winged square-shaped members 2 in the shield segment 1. The top plates of the number of winged square-shaped members 2 are connected through connectors.

[0046] Step 2: After the tunnel settlement is stable, cast post-cast strips 5 on both sides of each cast winged square-shaped member 2 respectively. After the construction of the post-cast strips 5 is completed, then every 1 to 4 rings of winged square-shaped members 2, cast post-cast beams 4 at the joints between the post-cast strips 5 and the shield segment 1.

[0047] Step 3: Finally, install or cast in-situ the anti-collision structures 6 on both sides of the top of the winged square-shaped members 2, and then complete the construction of the road surface 7 subsequently.

[0048] In Step 1, when precasting the winged square-shaped member 2, installation embedded parts for installing the temporary railing 3 are reserved on the top plate of the winged square-shaped member 2. After the installation of the winged square-shaped member 2 is completed, install the temporary railing 3 to prevent vehicles from entering the areas on both sides of the winged square-shaped member 2 during construction and avoid the overturning of the winged square-shaped member 2.

[0049] In Step 2, after the tunnel settlement is stable, both sides of the number of winged square-shaped members 2 are connected through anchor fittings to form an integral body, and the anchor fittings adopt wet joints or shear pins + prestressed steel bars.

[0050] Before pouring the post-cast strip 5 in Step 2, place horizontal main reinforcement bars in the post-cast strip 5; and before the construction of the post-cast beam 4, implant steel bars on the shield segment 1; then connect the horizontal main reinforcement bars with the implanted steel bars, and finally pour the post-cast beam 4 and the post-cast strip 5.

[0051] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field according to the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art should fall within the protection scope determined by the claims.

Claims

1. A fully precast lane slab system for single-layer shield tunnels, including shield segments, characterized in that, Inside the shield segment and along the length direction of the shield segment, winged cross-shaped members are sequentially arranged; variable cross-section plates are used for the cantilevered segments on both sides of several of the winged cross-shaped members. Post-cast strips are respectively arranged on both sides of each of the winged cross-shaped members, and two post-cast strips on both sides of each winged cross-shaped member form a group; post-cast beams are arranged at intervals of the joints between several groups of post-cast strips and the shield segment. Anti-collision structures are respectively arranged on both sides of the top of each of the winged cross-shaped members, and a road surface is laid in the area between the anti-collision structures on the tops of several of the winged cross-shaped members. The winged cross-shaped member is composed of a cross-shaped box body and wing plates respectively arranged on both sides of the cross-shaped box body, and the cross-shaped box body and the wing plates are of an integral structure. The width of the cross-shaped box body along the length direction of the shield segment is greater than the width of the wing plate along the length direction of the shield segment.

2. The precast full-lane slab system for shield tunnels according to claim 1, wherein, Several adjacent winged cross-shaped members are connected into a whole through connecting members.

3. The precast full-lane slab system for shield tunnels according to claim 1 or 2, characterized in that The top plate of the winged cross-shaped member is provided with a solid structure or a hollow structure.

4. The precast lane slab system for shield tunnels according to claim 3, characterized in that, For each group of post-cast strips, the post-cast beams are arranged at intervals of 1 to 4 rings of the winged cross-shaped members.

5. The construction method of the fully prefabricated lane slab system for shield tunnels according to any one of claims 1 to 4, characterized in that, It includes the following steps: Step 1: First, prefabricate several winged cross-shaped members, and then sequentially install the prefabricated winged cross-shaped members in the shield segment. The top plates between several adjacent winged cross-shaped members are connected through connecting members. Step 2: After the tunnel settlement is stable, pour the post-cast strips on both sides of each cast winged cross-shaped member respectively; after the construction of the post-cast strips is completed, pour the post-cast beams at the joints between the post-cast strips and the shield segment every 1 to 4 rings of the winged cross-shaped members. Step 3: Finally, install or cast in-situ the anti-collision structures on both sides of the top of the winged cross-shaped members, and then complete the construction of the road surface subsequently.

6. The single-layer shield tunnel full precast lane slab system and construction method according to claim 5, characterized in that, In Step 1, when prefabricating the winged cross-shaped members, installation embedded parts for installing temporary railings are reserved on the top plates of the winged cross-shaped members, and the temporary railings are installed after the installation of the winged cross-shaped members is completed.

7. The single-layer shield tunnel full precast lane slab system and construction method according to claim 6, characterized in that, In Step 2, after the tunnel settlement is stable, both sides of several winged cross-shaped members are connected through anchor bolts to form a whole.

8. The single-layer shield tunnel full precast lane slab system and construction method according to claim 7, characterized in that, In Step 2, before pouring the post-cast strips, place horizontal main reinforcement bars in the post-cast strips; and before the construction of the post-cast beams, implant steel bars in the shield segment; then connect the horizontal main reinforcement bars with the implanted steel bars, and finally pour the post-cast beams and post-cast strips.

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