Shield launching tunnel-entering structure under deep foundation pit support

Abstract

The utility model provides a shield launching hole entering structure under deep foundation pit supporting. A foundation pit at least comprises a first foundation pit protecting wall, a second foundation pit protecting wall and a third foundation pit protecting wall. A row of first fender posts are embedded in the first foundation pit retaining wall; second fender posts arranged on the two sides of the to-be-excavated starting hole and third fender posts arranged above the to-be-excavated starting hole are embedded in the third foundation pit retaining wall. The top ends of all the fender posts are connected through a crown beam; a first inclined strut and at least one second inclined strut are sequentially arranged between the first foundation pit protection wall and the third foundation pit protection wall from top to bottom, and the two ends of each inclined strut abut against the first fender post and the third fender post correspondingly. The tunnel entering structure further comprises a first anchor cable and a third anchor cable which are anchored into the side wall of the foundation pit in a downward inclined mode. Shield starting hole entering and tunneling construction under the backfill soil area deep foundation pit supporting state is achieved, engineering investment is reduced, meanwhile, interval tunnel work planning is optimized, and the construction period is greatly shortened.

Description

Technical Field

[0001] The utility model relates to the field of underground engineering construction, in particular to a shield starting hole entry structure under deep foundation pit support. Background Art

[0002] The shield starting and receiving construction is the most important part of shield construction, a major source of risk, and even the key to the success or failure of shield construction. Therefore, in the shield starting and receiving construction, construction units often invest a lot of manpower and material resources and adopt more conservative construction methods to ensure construction safety.

[0003] Before the existing shield machine starts, it is necessary to complete the pouring of the station (or section) main structure and backfilling of the foundation pit, and then cut the original retaining piles of the end foundation pit to reserve space for the entrance and exit. The project investment is high and the construction period is long, which is not conducive to the overall planning of the section shield machine. Sometimes it is restricted by the relocation of station pipelines and traffic diversion conditions, which will seriously affect the construction progress of the section tunnels of the entire line. Utility Model Content

[0004] In view of the defects in the prior art, the utility model provides an industrialized construction of the underground station structure transverse segment unit, which solves the technical problems of the existing shield starting scheme, such as long construction period and disadvantageous overall construction arrangement of the interval shield.

[0005] In order to achieve the above purpose, the utility model is implemented through the following technical solutions:

[0006] A shield tunneling structure for starting under deep foundation pit support, the foundation pit at least comprising a first foundation pit retaining wall and a second foundation pit retaining wall arranged on both sides of a track, and a third foundation pit retaining wall connecting the first foundation pit retaining wall and the second foundation pit retaining wall, the third foundation pit retaining wall being used to open a starting tunnel opening; a row of first retaining piles is embedded in the first foundation pit retaining wall; second retaining piles and third retaining piles are embedded in the third foundation pit retaining wall, and there are multiple second retaining piles and they are arranged on both sides of a starting tunnel opening to be excavated, and the third retaining piles are arranged above the starting tunnel opening to be excavated; the top ends of the first retaining piles, the second retaining piles and the third retaining piles are connected by a crown beam; a first diagonal brace and at least one second diagonal brace are arranged in sequence from top to bottom between the first foundation pit retaining wall and the third foundation pit retaining wall, and the two ends of the first diagonal brace and the second diagonal brace are respectively abutted against the first retaining pile and the third retaining pile;

[0007] The entry structure also includes a first anchor cable and a third anchor cable anchored downwardly into the side wall of the foundation pit, the first anchor cable passing through the first foundation pit retaining wall and anchored around the first retaining pile, and the third anchor cable passing through the third foundation pit retaining wall and anchored around the third retaining pile.

[0008] Optionally, the third anchor cable is anchored at one end away from the third retaining pile on the peripheral side of the tunnel primary support steel frame.

[0009] Optionally, the third retaining pile is provided with a concrete block on the side facing the foundation pit, and a pad is provided on the surface of the concrete block. The third anchor cable passes through the pad, the concrete block, the third retaining pile and the third foundation pit retaining wall in sequence, and the third anchor cable is anchored to the pad surface through an anchor.

[0010] Optionally, the cross-section of the backing plate is arched, and the anchor fits against the arch top surface of the backing plate.

[0011] Optionally, an L-shaped concrete beam is further provided between the first foundation pit retaining wall and the third foundation pit retaining wall, and the L-shaped concrete beam is fixedly connected to the first retaining pile, the second retaining pile and the third retaining pile respectively, and the two ends of the second diagonal brace are respectively abutted against the two arms of the L-shaped concrete beam.

[0012] Optionally, the first diagonal brace is a concrete support, and the second diagonal brace is a steel support.

[0013] It can be seen from the above technical solution that the beneficial effects of the utility model are:

[0014] The utility model provides a shield tunneling structure for starting deep foundation pit support, wherein the foundation pit at least comprises a first foundation pit retaining wall, a second foundation pit retaining wall and a third foundation pit retaining wall; a row of first retaining piles is embedded in the first foundation pit retaining wall; a second retaining pile and a third retaining pile are embedded in the third foundation pit retaining wall, and the second retaining piles have a plurality of them and are arranged on both sides of the starting tunnel to be excavated, and the third retaining pile is arranged above the starting tunnel to be excavated; the tops of the first retaining piles, the second retaining piles and the third retaining piles are provided with a plurality of first retaining piles and a plurality of second retaining piles. Connected by a crown beam; a first diagonal brace and at least one second diagonal brace are provided between the first foundation pit retaining wall and the third foundation pit retaining wall from top to bottom, and the two ends of the first diagonal brace and the second diagonal brace are respectively abutted against the first retaining pile and the third retaining pile; the tunnel entry structure also includes a first anchor cable and a third anchor cable that are anchored downwardly into the side wall of the foundation pit, the first anchor cable passes through the first foundation pit retaining wall and is anchored around the first retaining pile, and the third anchor cable passes through the third foundation pit retaining wall and is anchored around the third retaining pile. Based on the combination of pile support and pile-anchor support, it not only solves the space requirements for shield starting, but also solves the safety and technical problems of fill foundation pit support, realizes the shield starting, tunnel entry and excavation construction under the deep foundation pit support state in the backfill area, not only reduces the project investment, but also optimizes the planning arrangement of the interval tunnel, greatly shortening the construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the specific implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the specific implementation or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0016] Figure 1 This is a schematic diagram of a deep foundation pit;

[0017] Figure 2 This is a schematic diagram of the shield tunneling structure for deep foundation pit support;

[0018] Figure 3 for Figure 2 The enlarged view of point A in the middle;

[0019] Figure 4 It is the structural schematic diagram of the third retaining pile;

[0020] Figure 5 Schematic diagram of the three-dimensional structure of the pad;

[0021] Figure 6 is a cross-sectional view of the pad;

[0022] Reference numerals:

[0023] 1-foundation pit, 2-starting hole, 3-first retaining pile, 4-second retaining pile, 5-third retaining pile, 6-crown beam, 7-first diagonal brace, 8-second diagonal brace;

[0024] 11-first foundation pit retaining wall, 12-second foundation pit retaining wall, 13-third foundation pit retaining wall, 31-first anchor cable, 51-concrete block, 52-third anchor cable, 53-pad, 54-connecting reinforcement, 81-L-shaped concrete beam. DETAILED DESCRIPTION

[0025] The following embodiments of the technical solution of the utility model are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the utility model, and are therefore only used as examples, and cannot be used to limit the protection scope of the utility model.

[0026] See also Figure 1-3The utility model provides a shield starting tunneling structure under deep foundation pit support. The foundation pit 1 at least includes a first foundation pit retaining wall 11 and a second foundation pit retaining wall 12 arranged on both sides of the track, and a third foundation pit retaining wall 13 connecting the first foundation pit retaining wall 11 and the second foundation pit retaining wall 12, and the third foundation pit retaining wall 13 is used to open a starting tunnel opening 2. A row of first retaining piles 3 are embedded in the first foundation pit retaining wall 11; second retaining piles 4 and third retaining piles 5 are embedded in the third foundation pit retaining wall 13, and the second retaining piles 4 have multiple pieces and are arranged on both sides of the starting tunnel opening 2 to be excavated, and the third retaining piles 5 are arranged above the starting tunnel opening 2 to be excavated. The tops of the first retaining piles 3, the second retaining piles 4 and the third retaining piles 5 are connected by a crown beam 6. A first diagonal brace 7 and at least one second diagonal brace 8 are sequentially arranged between the first foundation pit retaining wall 11 and the third foundation pit retaining wall 13 from top to bottom, and the two ends of the first diagonal brace 7 and the second diagonal brace 8 are respectively abutted against the first retaining pile 3 and the third retaining pile 5. The entry structure also includes a first anchor cable 31 and a third anchor cable 52 anchored downwardly into the side wall of the foundation pit 1, the first anchor cable 31 passes through the first foundation pit retaining wall 11 and is anchored around the first retaining pile 3, and the third anchor cable 52 passes through the third foundation pit retaining wall 13 and is anchored around the third retaining pile 5. The second retaining pile 4 has the same structure as the first retaining pile 3, and the first anchor cable 31 is also arranged around the second retaining pile 4, and all anchor cables should be anchored below the potential sliding surface.

[0027] As a further improvement to the above solution, the third anchor cable 52 is anchored at one end away from the third retaining pile 5 on the side of the tunnel primary support steel frame. Figure 4-6 The third retaining pile 5 is provided with a concrete block 51 on the side facing the foundation pit 1. The concrete block 51 is formed by supporting a formwork and casting on site after planting reinforcement on the surface of the third retaining pile 5. The surface of the concrete block 51 is provided with a pad 53, which can be welded and fixed to the connecting reinforcement 54 implanted in the third retaining pile 5. The third anchor cable 52 passes through the pad 53, the concrete block 51, the third retaining pile 5 and the third foundation pit retaining wall 13 in sequence, and the third anchor cable 52 is anchored on the surface of the pad 53 through an anchor. The pad 53 has an arched cross-section, and the anchor is fitted with the arch top surface of the pad 53. The arched structure evenly spreads the load to the third retaining pile 5, thereby increasing the force-bearing area, especially for the prestress applied by the third anchor cable 52 when the tunnel initial support steel frame is anchored.

[0028] As a further improvement to the above scheme, an L-shaped concrete beam 81 is further provided between the first foundation pit retaining wall 11 and the third foundation pit retaining wall 13, and the L-shaped concrete beam 81 is respectively fixedly connected to the first retaining pile 3, the second retaining pile 4 and the third retaining pile 5, and the two ends of the second diagonal brace 8 are respectively abutted against the two arms of the L-shaped concrete beam 81, and the middle or bottom of each retaining pile is connected by the L-shaped concrete beam 81, and a triangular structure is formed with the second diagonal brace 8. By setting the first diagonal brace, the second diagonal brace, the crown beam and the L-shaped concrete beam, the first retaining pile is incorporated into the hole support system, and the force is synergistically exerted, which effectively improves the stability of the hole support structure.

[0029] As a further improvement to the above scheme, the first diagonal brace 7 is a concrete support and is cast integrally with the crown beam 6, and the second diagonal brace 8 is a steel support. Concrete supports can withstand both compression and tension, and can withstand the impact of construction equipment, and have high rigidity and small overall deformation; while steel supports can only withstand compression but not tension, and have low rigidity and large overall deformation. Their stability depends on the quality of on-site assembly, including the centering accuracy of the node axis, the degree of eccentricity of the rod force, and the reliability of the node connection. Instability of individual nodes will cause overall damage. Therefore, concrete supports are used at the top of the third retaining pile 5 to form a stable support system, while steel supports are used in the middle or bottom support of the third retaining pile 5 to facilitate later removal.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the utility model, and they should all be included in the scope of the claims and specification of the utility model.

Claims

1. A shield tunneling starting tunneling structure under deep foundation pit support, the foundation pit (1) comprising at least a first foundation pit retaining wall (11) and a second foundation pit retaining wall (12) arranged on both sides of a track, and a third foundation pit retaining wall (13) connecting the first foundation pit retaining wall (11) and the second foundation pit retaining wall (12), the third foundation pit retaining wall (13) being used to open a starting tunnel opening (2); characterized in that: A row of first retaining piles (3) is embedded in the first foundation pit retaining wall (11); a second retaining pile (4) and a third retaining pile (5) are embedded in the third foundation pit retaining wall (13), and the second retaining pile (4) has a plurality of piles and is disposed on both sides of the starting hole (2) to be excavated, and the third retaining pile (5) is disposed above the starting hole (2) to be excavated; the tops of the first retaining pile (3), the second retaining pile (4) and the third retaining pile (5) are connected by a crown beam (6); a first diagonal brace (7) and at least one second diagonal brace (8) are sequentially disposed between the first foundation pit retaining wall (11) and the third foundation pit retaining wall (13) from top to bottom, and the two ends of the first diagonal brace (7) and the second diagonal brace (8) are respectively in contact with the first retaining pile (3) and the third retaining pile (5); The entry structure further comprises a first anchor cable (31) and a third anchor cable (52) which are anchored downwardly and obliquely into the side wall of the foundation pit (1); the first anchor cable (31) passes through the first foundation pit retaining wall (11) and is anchored around the first retaining pile (3); and the third anchor cable (52) passes through the third foundation pit retaining wall (13) and is anchored around the third retaining pile (5).

2. The shield tunneling structure for starting deep foundation pit support according to claim 1 is characterized in that: One end of the third anchor cable (52) away from the third retaining pile (5) is anchored on the peripheral side of the tunnel primary support steel frame.

3. A shield tunneling starting structure under deep foundation pit support according to claim 1 or 2, characterized in that: A concrete block (51) is provided on the side of the third retaining pile (5) facing the foundation pit (1), a pad (53) is provided on the surface of the concrete block (51), the third anchor cable (52) passes through the pad (53), the concrete block (51), the third retaining pile (5) and the third foundation pit retaining wall (13) in sequence, and the third anchor cable (52) is anchored to the surface of the pad (53) by an anchor.

4. The shield tunneling structure for starting deep foundation pit support according to claim 3 is characterized in that: The backing plate (53) has an arched cross-section, and the anchor is in contact with the arched top surface of the backing plate (53).

5. The shield tunneling structure for starting deep foundation pit support according to claim 1 is characterized in that: An L-shaped concrete beam (81) is further provided between the first foundation pit retaining wall (11) and the third foundation pit retaining wall (13); the L-shaped concrete beam (81) is respectively fixedly connected to the first retaining pile (3), the second retaining pile (4) and the third retaining pile (5); and the two ends of the second diagonal brace (8) are respectively abutted against two arms of the L-shaped concrete beam (81).

6. The shield tunneling structure for starting and entering a deep foundation pit according to claim 1, characterized in that: The first diagonal brace (7) is a concrete support, and the second diagonal brace (8) is a steel support.

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