Construction Method of Anti-buoyancy Structure System for Ultra-shallow Shield Tunneling under Terrain Constraints

Abstract

This invention provides a construction method for an anti-buoyancy structure system for ultra-shallow buried shield tunnels in terrain-constrained conditions. Before the tunnel boring machine reaches the ultra-shallow section, large pipe roofs are installed at intervals along the hillside on one side of the tunnel axis, and foundation piles are installed at intervals on the other side. A concrete beam is constructed on top of each foundation pile, consisting of a top concrete beam and a connecting beam. Simultaneously, end concrete beams are constructed at the ends of the large pipe roofs, connecting end-to-end to form a closed beam. Reinforcing steel for a concrete slab is tied between the concrete beams and the end concrete beams of the large pipe roofs, and then concrete is poured to complete the construction of the concrete cover plate, which is positioned above the shield tunnel. The concrete beams, concrete cover plate, and end concrete beams of the large pipe roofs are connected as a whole, forming an anti-buoyancy structure system together with the foundation piles and large pipe roofs. This invention is simple to operate, cost-effective, and safe and reliable.

Description

Technical Field

[0001] This invention belongs to the field of shield tunneling technology, and specifically relates to a construction method for an anti-buoyancy structure system for ultra-shallow buried shield tunnels with limited terrain. Background Technology

[0002] Currently, with the rapid development of cities, shield tunnels are often affected by geological conditions, surrounding buildings and structures, and topography. The shallow burial depth of shield tunnels makes it difficult to meet the anti-buoyancy requirements. Conventional solutions include adjusting the longitudinal slope of the shield, adjusting the depth of the receiving shaft, and adjusting the tunnel slope to increase the burial depth. Alternatively, a beam-slab and pile foundation system can be used to resist buoyancy. However, due to the influence of mountainous terrain in the surrounding environment, the above-mentioned anti-buoyancy systems are difficult to construct. Removing the mountain will result in a large amount of engineering work and increased costs. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a design method for an anti-buoyancy structure system for ultra-shallow buried shield tunnels in terrain-constrained environments. This method is simple to operate, cost-effective, and safe and reliable.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] This invention provides a construction method for an anti-buoyancy structure system for terrain-constrained ultra-shallow shield tunnels, the method comprising the following steps:

[0006] Step S1: Before the tunnel boring machine reaches the ultra-shallow buried section, large pipe sheds are set at intervals along the hillside on one side of the tunnel axis and foundation piles are set at intervals on the other side of the tunnel axis.

[0007] Step S2: Concrete beams are constructed at the top of the foundation piles. The concrete beams are composed of concrete beams at the top of the foundation piles and connecting beams. At the same time, concrete beams are constructed at the ends of the large pipe sheds. The concrete beams are connected end to end with the concrete beams at the ends of the large pipe sheds to form closed beams.

[0008] Step S3: Tie the reinforcing steel bars of the concrete slab between the concrete beam and the concrete beam at the end of the large pipe shed, and then pour the concrete to complete the construction of the concrete cover plate. The concrete cover plate is located above the shield tunnel. The concrete beam, the concrete cover plate, and the concrete beam at the end of the large pipe shed are connected into a whole, forming an anti-buoyancy structure system together with the foundation piles and the large pipe shed.

[0009] In step S4, after the foundation piles, large pipe shed, concrete beams, concrete beams at the ends of the large pipe shed, and concrete cover plate structure are reinforced, the shield tunneling passes through the ultra-shallow buried section, completes the internal structure, and restores the ground passage.

[0010] Preferably, the concrete beam includes a concrete beam at the top of the foundation pile and a connecting beam, wherein the concrete beam at the top of the foundation pile, the connecting beam, and the concrete beam at the end of the large pipe shed are connected end to end.

[0011] Preferably, the concrete beam includes a concrete beam at the top of the foundation pile and two connecting beams, with the two ends of the large pipe shed end concrete beam connected to the concrete beam at the top of the foundation pile through the two connecting beams respectively.

[0012] Preferably, in step S2, after excavating the pile head of the foundation pile and breaking the pile head, the reinforcing bars are straightened, and the reinforcing bars of the concrete beam and the end concrete beam of the large pipe shed are tied simultaneously. Then, the concrete beam and the end concrete beam of the large pipe shed are poured. Before pouring the concrete beam and the end concrete beam of the large pipe shed, the reinforcing bar joints of the concrete slab are pre-embedded.

[0013] Preferably, in step S1, cement grout is injected into the large pipe shed and the ends of the large pipe shed are sealed with sealing steel plates.

[0014] Preferably, the large pipe shed is arranged in one or more rows, and the inclination angle of the large pipe shed is within the range of 0° to 45°.

[0015] Preferably, the spacing between the large pipe sheds is 2 to 2.5 times the diameter of the pipe shed openings; the spacing between the foundation piles is 3 to 5 times the pile diameter, and the pile length meets the requirements for pull-out bearing capacity.

[0016] Preferably, in step S3, before tying the reinforcing bars of the concrete slab, the sides of the concrete beams and the concrete beams at the ends of the large pipe shed that are to be connected to the concrete slab are roughened.

[0017] The present invention has the following beneficial effects:

[0018] This invention provides a construction method for an anti-buoyancy structure system for ultra-shallow buried shield tunnels in terrain-constrained conditions. Large pipe roofs are installed at intervals along the hillside on one side of the shield tunnel axis, while foundation piles are installed at intervals on the other side of the shield tunnel axis. This maximizes the use of existing terrain, reduces slope excavation, and simultaneously meets the tunnel's anti-buoyancy requirements. Furthermore, the surface passage can be used normally while the shield tunnel is in operation. This invention is simple to operate, cost-effective, and safe and reliable. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention.

[0020] Figure 1 This is a schematic diagram of the anti-buoyancy structure system of an ultra-shallow buried shield tunnel with terrain constraints, according to an embodiment of the present invention.

[0021] Figure 2 for Figure 1 A cross-sectional schematic diagram.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Shield tunnel; 2. Foundation piles; 3. Concrete beams; 31. Concrete beams at the top of foundation piles; 32. Connecting beams; 4. Concrete cap slabs; 5. Concrete beams at the ends of the large pipe shed; 6. Sealing steel plates; 7. Large pipe shed; 8. Hillside. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] This embodiment provides a construction method for an anti-buoyancy structure system for terrain-constrained ultra-shallow buried shield tunnels, such as... Figure 1 and Figure 2 As shown, the method includes the following steps:

[0026] Step S1: Before the tunnel boring machine reaches the ultra-shallow buried section, large pipe sheds 7 are set at intervals along the hillside 8 on one side of the tunnel axis 1, and foundation piles 2 are set at intervals on the other side of the tunnel axis 1.

[0027] In step S2, a concrete beam 3 is constructed on the top of the foundation pile 2. The concrete beam 3 is composed of a concrete beam 31 at the top of the foundation pile and a connecting beam 32. At the same time, a concrete beam 5 at the end of the large pipe shed 7 is constructed. The concrete beam 3 and the concrete beam 5 at the end of the large pipe shed are connected end to end to form a closed beam.

[0028] Step S3: Tie the reinforcing bars of the concrete slab 4 between the concrete beam 3 and the concrete beam 5 at the end of the large pipe shed, and then pour the concrete to complete the construction of the concrete cover 4. The concrete cover 4 is located above the shield tunnel 1. The concrete beam 3, the concrete cover 4, and the concrete beam 5 at the end of the large pipe shed are connected into a whole, forming an anti-buoyancy structure system together with the foundation pile 2 and the large pipe shed 7.

[0029] In step S4, after the foundation piles 2, the large pipe shed 7, the concrete beam 3, the concrete beam at the end of the large pipe shed 5, and the concrete cover plate 4 are reinforced, the shield tunneling passes through the ultra-shallow buried section, completes the internal structure, and restores the ground passage.

[0030] Furthermore, the concrete beam 3 includes a concrete beam 31 at the top of the pile and a connecting beam 32, with the concrete beam 31 at the top of the pile, the connecting beam 32, and the concrete beam 5 at the end of the large pipe shed connected end to end; or the concrete beam 3 includes a concrete beam 31 at the top of the pile and two connecting beams 32, with the two ends of the concrete beam 5 at the end of the large pipe shed connected to the concrete beam 31 at the top of the pile through the two connecting beams 32 respectively.

[0031] In this embodiment, the concrete beam 3 includes a concrete beam 31 at the top of the foundation pile and a connecting beam 32. The concrete beam 31 at the top of the foundation pile, the connecting beam 32, and the concrete beam 5 at the end of the large pipe shed are connected end to end.

[0032] Further, in step S2, the pile head of the foundation pile 2 is excavated, the pile head is broken, the reinforcing bars are straightened, and the reinforcing bars of the concrete beam 3 and the end concrete beam 5 of the large pipe shed are tied simultaneously. Then the concrete beam 3 and the end concrete beam 5 of the large pipe shed are poured. Before pouring the concrete beam 3 and the end concrete beam 5 of the large pipe shed, the reinforcing bar joints of the concrete slab 4 are pre-embedded.

[0033] Furthermore, in step S1, cement grout is injected into the large pipe shed 7 and the ends of the large pipe shed 7 are sealed with sealing steel plates 6.

[0034] Furthermore, the large pipe shed 7 is arranged in one or more rows, and the inclination angle of the large pipe shed 7 is within the range of 0° to 45°.

[0035] Furthermore, the spacing between the large pipe sheds 7 is 2 to 2.5 times the diameter of the large pipe shed 7 holes; the spacing between the foundation piles 2 is 3 to 5 times the pile diameter, and the pile length must meet the requirements for pull-out bearing capacity.

[0036] Furthermore, in step S3, before binding the reinforcing bars of the concrete slab 4, the sides of the concrete beam 3 and the concrete beam 5 at the end of the large pipe shed that are to be connected to the concrete slab 4 are roughened.

[0037] Furthermore, the foundation pile 2 must meet the requirements for pile pull-out resistance and overall structural pull-out bearing capacity, and the end connection of the large pipe shed 7 must meet the shear resistance requirements, so that the anti-buoyancy safety factor of the shield tunnel 1 during the operation period is not less than 1.1.

[0038] As can be seen from the above technical solutions, the construction method of the terrain-constrained ultra-shallow buried shield tunnel anti-buoyancy structure system provided in this embodiment can maximize the use of existing terrain, reduce slope excavation, and simultaneously meet the tunnel's anti-buoyancy requirements. Furthermore, during the operation of the shield tunnel, the normal use of the surface passage can be guaranteed. This invention is simple to operate, cost-effective, safe, and reliable; it is applicable to tunnel projects such as railway tunnels, subway tunnels, and highway tunnels.

[0039] The embodiments of the present invention have been described in detail above through examples, but the content described is only an exemplary embodiment of the present invention and should not be considered as limiting the scope of implementation of the present invention. The protection scope of the present invention is defined by the claims. Any technical solutions designed by those skilled in the art using the technical solutions described in the embodiments of the present invention, or designed by those skilled in the art under the inspiration of the technical solutions of the embodiments of the present invention, within the substance and protection scope of the present invention, to achieve the above-mentioned technical effects, or any equivalent changes and improvements made to the scope of the application, should still fall within the patent protection scope of the present invention.

Claims

1. A construction method for an anti-buoyancy structure system for ultra-shallow buried shield tunnels in terrain-constrained conditions, characterized in that, The method includes the following steps: Step S1: Before the tunnel boring machine reaches the ultra-shallow buried section, large pipe sheds (7) are set at intervals along the hillside (8) on one side of the shield tunnel (1) axis, and foundation piles (2) are set at intervals on the other side of the shield tunnel (1) axis. Step S2: Concrete beam (3) is constructed on the top of the foundation pile (2). The concrete beam (3) is composed of the concrete beam (31) at the top of the foundation pile and the connecting beam (32). At the same time, a concrete beam (5) at the end of the large pipe shed (7) is constructed. The concrete beam (3) and the concrete beam (5) at the end of the large pipe shed are connected end to end to form a closed beam. Step S3: Tie the reinforcing steel of the concrete slab (4) between the concrete beam (3) and the concrete beam (5) at the end of the large pipe shed, and then pour concrete to complete the construction of the concrete cover plate (4). The concrete cover plate (4) is located above the shield tunnel (1). The concrete beam (3), the concrete cover plate (4), and the concrete beam (5) at the end of the large pipe shed are connected into a whole, forming an anti-buoyancy structure system together with the foundation pile (2) and the large pipe shed (7). In step S4, after the foundation piles (2), the large pipe shed (7), the concrete beam (3), the concrete beam at the end of the large pipe shed (5), and the concrete cover plate (4) are structurally reinforced, the shield tunneling passes through the ultra-shallow buried section, completes the internal structure, and restores the ground passage. In step S2, the pile head of the foundation pile (2) is excavated, the pile head is broken, the reinforcing bars are straightened, and the reinforcing bars of the concrete beam (3) and the end concrete beam (5) of the large pipe shed are tied simultaneously. Then the concrete beam (3) and the end concrete beam (5) of the large pipe shed are poured. Before the concrete beam (3) and the end concrete beam (5) of the large pipe shed are poured, the reinforcing bar joints of the concrete slab (4) are pre-embedded.

2. The construction method of the anti-buoyancy structure system for terrain-constrained ultra-shallow buried shield tunnels according to claim 1, characterized in that, The concrete beam (3) includes a concrete beam (31) at the top of the foundation pile and a connecting beam (32), and the concrete beam (31) at the top of the foundation pile, the connecting beam (32), and the concrete beam (5) at the end of the large pipe shed are connected end to end.

3. The construction method of the anti-buoyancy structure system for terrain-constrained ultra-shallow buried shield tunnels according to claim 1, characterized in that, The concrete beam (3) includes a concrete beam (31) at the top of the foundation pile and two connecting beams (32). The two ends of the large pipe shed end concrete beam (5) are connected to the concrete beam (31) at the top of the foundation pile through the two connecting beams (32).

4. The construction method of the anti-buoyancy structure system for terrain-constrained ultra-shallow buried shield tunnels according to claim 1, characterized in that, In step S1, cement grout is injected into the large pipe shed (7) and the end of the large pipe shed (7) is sealed with a sealing steel plate (6).

5. The construction method of the anti-buoyancy structure system for terrain-constrained ultra-shallow buried shield tunnels according to claim 1, characterized in that, The large pipe shed (7) is arranged in one or more rows, and the inclination angle of the large pipe shed (7) is within the range of 0° to 45°.

6. The construction method of the anti-buoyancy structure system for terrain-constrained ultra-shallow buried shield tunnels according to claim 1, characterized in that, The spacing of the large pipe shed (7) is 2 to 2.5 times the diameter of the large pipe shed (7); the spacing of the foundation piles (2) is 3 to 5 times the pile diameter, and the pile length meets the requirements of pull-out bearing capacity.

7. The construction method of the anti-buoyancy structure system for terrain-constrained ultra-shallow buried shield tunnels according to claim 1, characterized in that, In step S3, before binding the reinforcing bars of the concrete slab (4), the sides of the concrete beam (3) and the concrete beam (5) at the end of the large pipe shed that are to be connected to the concrete slab (4) are roughened.

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