A shield tunnel segment structure and shaft connection node and construction method thereof

Abstract

The present invention provides a shield tunnel segment structure and shaft connection node, including a flexible filling layer arranged between the segment structure and the shaft wall, a cast-in-place portal ring beam, bolt holes embedded in the portal ring beam, and connecting bolts connected with the bolt holes, an inner ring steel plate embedded in the end face of the segment structure facing the portal ring beam, an outer ring steel plate embedded in the end face of the shaft wall facing the portal ring beam, one end of the bolt hole is fixed to the inner ring steel plate, and the inner ring steel plate is connected to the portal ring beam through connecting bolts. The present invention achieves the purpose of reducing the seismic response of the shield tunnel and shaft connection node and limiting the seismic deformation within an allowable range by forming a semi-flexible and semi-rigid connection node between the shield tunnel and the shaft. The present invention also provides a construction method for a shield tunnel segment structure and shaft connection node.

Description

Technical Field

[0001] The invention belongs to the field of shield tunnel engineering, and specifically relates to the seismic treatment of a shield tunnel, and in particular to a shield tunnel segment structure and shaft connection node and a construction method thereof. Background Art

[0002] The shield method is currently the most commonly used method for constructing tunnels in soft strata and urban environments at home and abroad. Due to the requirements of the construction method itself, the shield machine generally needs to be launched and received in the shaft. After the construction is completed, the tunnel structure needs to be connected to the shaft structure. The connection structure between the shield tunnel and the shaft should have the following functions: First, the gap between the segment structure and the shaft portal ring frame is blocked to prevent water and soil from gushing out from this part during operation; second, the segment joint sealing gasket is prevented from loosening when the negative ring is removed after the shield is launched or the machine is dismantled after the shield is received, thereby affecting the waterproof effect of the tunnel; third, it can limit the deformation of the tunnel under the action of earthquakes, and prevent excessive differential deformation between the main structure of the tunnel and the shaft, and between the internal structure of the tunnel and the internal structure of the shaft, which affects driving safety.

[0003] The existing technology is to use the tunnel ring beam to connect the segment structure and the shaft wall. The specific method is: pre-embed annular steel plates (referred to as inner ring steel plates and outer ring steel plates respectively) at the end of the segment and around the hole in the shaft wall, and then weld double rows of steel bars on the inner ring steel plates and the outer ring steel plates to achieve the connection between the segment structure, the shaft wall and the tunnel ring beam ( Figure 1 ), and at the same time, waterproof strips are set on the inner and outer ring steel plates to prevent groundwater from leaking into the tunnel. The main problems of the existing technology are:

[0004] (1) The hole in the shaft wall is slightly larger than the outer diameter of the shield tunnel segment (the gap between the two is generally 40 cm), resulting in a small radial thickness of the portal ring beam; and due to the great difference in stiffness between the segment structure and the shaft, the deformation difference between the two under earthquake action is large, resulting in the portal ring beam having to bear a large bending moment and axial force, which is prone to cracking or even breaking, thus affecting the structural safety and operational safety during earthquakes. Theoretical studies have shown that the node where the segment structure and the shaft are connected is one of the weakest parts of the shield tunnel in terms of earthquake resistance. Earthquake disaster surveys have also shown that the damage ratio of the connection between the shield tunnel and the shaft is much higher than that of other sections. If a flexible connection is used, the constraint capacity of the differential deformation between the segment structure and the shaft under earthquake conditions is too weak, which is not conducive to the waterproofing of the segment joints and will also cause misalignment between the segment structure and the shaft, thus affecting the structural safety and operational safety. Therefore, for tunnels in high-intensity areas or with large earthquake responses, neither rigid nor flexible connections can be used between the shield tunnel and the shaft. Instead, semi-flexible and semi-rigid connections should be used.

[0005] (2) The portal ring beam is cast with ordinary reinforced concrete, which has weak deformation capacity and will cause cracks even with a small amount of deformation. Therefore, it is necessary to improve the deformation capacity of the portal ring beam. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a shield tunnel segment structure and shaft connection node and a construction method thereof. The present invention at least solves some of the problems in the prior art.

[0007] The present invention is achieved in that:

[0008] The present invention provides a connecting node between a segment structure and a shaft of a shield tunnel, comprising a flexible filling layer arranged between the segment structure and the shaft wall, a cast-in-place portal ring beam, bolt holes embedded in the portal ring beam, and connecting bolts connected with the bolt holes, an inner ring steel plate is embedded in the end face of the segment structure facing the portal ring beam, an outer ring steel plate is embedded in the end face of the shaft wall facing the portal ring beam, one end of the bolt hole is fixed to the inner ring steel plate, and the inner ring steel plate is connected to the portal ring beam through the connecting bolts.

[0009] Furthermore, a wedge-shaped notch is provided on one side of the shaft wall facing the flexible filling layer, and the wedge-shaped notch is filled with the flexible filling material.

[0010] Furthermore, a plurality of rows of connecting anchor bars connected to the tunnel portal ring beam are provided on the outer ring steel plate.

[0011] Furthermore, a first waterproof strip is provided at the connection portion between the portal ring beam and the segment structure.

[0012] Furthermore, a second waterproof strip is provided at the connection portion between the tunnel portal ring beam and the shaft wall.

[0013] Furthermore, the portal ring beam is cast in situ using steel fiber reinforced concrete.

[0014] Furthermore, the inner diameter of the bolt hole is larger than the outer diameter of the connecting bolt.

[0015] The present invention also provides a method for constructing a connection node between a shield tunnel segment structure and a shaft, comprising the following steps:

[0016] S1. Carry out the construction of the shaft and make the pre-embedding of the outer ring steel plate and the reservation of the wedge-shaped gap according to the design requirements;

[0017] S2. Carry out shield tunnel construction and pre-embed the inner ring steel plate according to the design requirements;

[0018] S3, mounting bolt hole;

[0019] S4. Install the shaft wall connecting anchor bars;

[0020] S5. Clean the debris in the remaining gap between the segment structure and the holes in the shaft wall, and install a flexible filling layer;

[0021] S6. Install the flexible filling material for the wedge-shaped gap outside the hole in the shaft wall;

[0022] S7. Install the first waterproof strip at the connection between the portal ring beam and the segment structure;

[0023] S8. Install the second waterproof strip at the connection between the tunnel gate ring beam and the shaft wall;

[0024] S9, pour the portal ring beam and cure it to the designed strength;

[0025] S10. Install the connecting bolts;

[0026] S11. Complete the construction.

[0027] The present invention has the following beneficial effects:

[0028] 1. The shield tunnel segment structure and shaft connection node proposed in the present invention can effectively reduce the seismic response of the shield tunnel, reduce the damage to the shield tunnel segment structure and the portal ring beam under the action of earthquake, and improve the seismic performance and structural toughness of the shield tunnel.

[0029] 2. Compared with the connection structure between the existing shield tunnel segment structure and the shaft, the construction method remains basically unchanged, the pre-embedded method of the annular steel plate remains unchanged, the water-stopping method of the joint surface remains unchanged, and only the connection bolts between the segment structure and the portal ring beam have changed the construction process requirements. However, the present invention significantly improves the seismic resistance and toughness of the structure.

[0030] 3. While realizing the waterproofing function of the joint surface between the portal ring beam and the shield tunnel segment structure, and the joint surface between the portal ring beam and the shaft wall, the present invention achieves the purpose of reducing the seismic response of the part and limiting the seismic deformation within the allowable range by appropriately reducing the bending stiffness of the portal ring beam, improving the deformation capacity of the portal ring beam itself, and allowing moderate differential deformation between the segment structure and the shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 It is a schematic diagram of the connection between the pipe segment structure and the shaft wall in the prior art;

[0033] Figure 2An overall schematic diagram of the connection between the pipe segment structure and the shaft wall provided by an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of bolt connection between a portal ring beam and a segment end face provided by an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of a wedge-shaped notch and a flexible filling material on the outside of a hole in a shaft wall provided by an embodiment of the present invention;

[0036] Figure 5 A schematic diagram of the connection between the tunnel gate ring beam and the shaft wall provided in an embodiment of the present invention;

[0037] Figure 6 A schematic diagram of the connection between the portal ring beam and the end face of the segment structure provided in an embodiment of the present invention.

[0038] In the figure: segment structure 1, inner ring steel plate 1-1, shaft wall 2 (shaft wall), outer ring steel plate 2-1, portal ring beam 3, connecting bolts 4, connecting anchor bars 5, bolt holes 6, first waterproof strip 7, second waterproof strip 8, flexible filling layer 9, wedge-shaped notch 10, flexible filling material 11, grouting filling 12, double-row anchor bars 13, shaft enclosure structure 14. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] like Figure 2-Figure 6 Embodiment 1 of the present invention provides a connection node between a shield tunnel segment structure and a shaft, comprising a shield tunnel segment structure 1 and an inner ring steel plate 1-1 embedded in the end face, a shaft wall 2 and an outer ring steel plate 2-1 embedded in the surface, a cast-in-place large strain capacity steel fiber reinforced concrete portal ring beam 3, connecting bolts 4 between the portal ring beam and the end face of the segment structure, connecting anchor bars 5 between the portal ring beam and the shaft wall, bolt holes 6 for installing the connecting bolts 4, a first waterproof strip 7 at the connection between the portal ring beam and the segment, a second waterproof strip 8 at the connection between the portal ring beam and the shaft, a flexible filling layer 9 for the remaining gap between the segment structure 1 and the shaft wall hole, a wedge-shaped notch 10 outside the shaft wall hole, and a flexible filling material 11 for the wedge-shaped notch outside the shaft wall hole, etc.

[0041] The portal ring beam 3 and the shaft wall 2 are fixedly connected, which can transmit bending moment, axial force and shear force; the portal ring beam 3 and the segment structure 1 are hinged axially, which can transmit axial force but not bending moment, and prevent the two from separating; the radial direction is first slidingly connected and then hinged, allowing the end of the segment structure 1 to produce a certain amount of radial movement first, and then form a hinge with the portal ring beam 3, which can transmit shear force and prevent excessive differential deformation between the two.

[0042] By reasonably setting the radial height and width of the wedge-shaped notch 10 outside the hole in the shaft wall and the thickness of the portal ring beam 3, the portal ring beam 3 has a suitable span and thickness, thereby achieving the purpose of reducing the bending stiffness and shear stiffness of the portal ring beam.

[0043] The portal ring beam 3 is cast in situ using steel fiber reinforced concrete with high ductility and large strain capacity.

[0044] By providing the flexible filling material 11 in the wedge-shaped notch outside the hole in the shaft wall, the constraint of the shaft wall 2 on the tunnel portal ring beam 3 when it is bent and deformed in the tunnel direction is reduced.

[0045] The bolt hole 6 for installing the connecting bolt 4 has a diameter slightly larger than the outer diameter of the connecting bolt 4, and the center of the connecting bolt 4 is substantially the same as the center of the bolt hole 6, so that the end of the segment structure 1 has a certain horizontal and vertical displacement space, but the displacement can be limited within the design allowable range.

[0046] The present invention achieves the purpose of reducing the seismic response of the connection node between the shield tunnel and the shaft and limiting the seismic deformation within an allowable range by forming a semi-flexible and semi-rigid connection node between the shield tunnel and the shaft.

[0047] Embodiment 2 of the present invention provides a method for constructing a connection node between a shield tunnel segment structure and a shaft, comprising the following steps:

[0048] (1) Perform seismic calculations on shield tunnels with traditional rigid connections, obtain the seismic responses of the shield tunnel segment structure 1 and the portal ring beam 3, analyze their impact on safety, and propose whether measures need to be taken to reduce the seismic response;

[0049] (2) According to the allowable strength and allowable deformation value of the shield tunnel segment structure 1 under earthquake action, different schemes for the portal ring beam 3 and its connection with the segment structure 1 and the shaft wall 2 are formulated, and seismic response analysis is performed to obtain the most reasonable design parameters, including: the height, width, structural material and reinforcement of the portal ring beam 3, the number, diameter and material of the connecting bolts 4, the gap between the connecting bolts 4 and the bolt holes 6, the number, diameter and material of the connecting anchor bars 5 between the portal ring beam 3 and the shaft wall 2, the material of the flexible filling layer 9 of the remaining gap between the holes of the segment structure 1 and the shaft wall 2, the width and height of the wedge-shaped notch 10 outside the hole of the shaft wall 2, the material of the flexible filling material 11 of the wedge-shaped notch 10 outside the hole of the shaft wall, the pre-embedding method of the inner ring steel plate 1-1, the pre-embedding method of the outer ring steel plate 2-1, etc.;

[0050] (3) Carry out the construction of the vertical shaft, and embed the outer ring steel plate 2-1 and reserve the wedge-shaped notch 10 according to the design requirements;

[0051] (4) Conduct shield tunnel construction and pre-embed the inner ring steel plate 1-1 according to design requirements;

[0052] (5) When the conditions for constructing the opening connection node are met, the construction shall be carried out as follows:

[0053] ①Installation bolt hole 6;

[0054] ②Install the shaft wall connecting anchor bars 5;

[0055] ③ Clean the debris in the remaining gap between the segment structure 1 and the hole in the shaft wall, and install the flexible filling layer 9;

[0056] ④ Install the flexible filling material 11 of the wedge-shaped notch 10 outside the hole in the shaft wall;

[0057] ⑤ Install the first waterproof strip 7 at the connection between the tunnel ring beam 3 and the segment structure 1;

[0058] ⑥ Install the second waterproof strip 8 at the connection between the tunnel gate ring beam 3 and the shaft wall 2;

[0059] ⑦ Cast the portal ring beam 3 and maintain it to the designed strength;

[0060] ⑧Install the connecting bolt 4;

[0061] (6) Complete the construction.

[0062] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A shield tunnel segment structure and shaft connection node, characterized in that: The invention comprises a flexible filling layer (9) arranged between a segment structure (1) and a shaft wall (2), a cast-in-place portal ring beam (3), a bolt hole (6) pre-buried in the portal ring beam (3), and a connecting bolt (4) connected to the bolt hole (6); an inner ring steel plate (1-1) is pre-buried on the end face of the segment structure (1) facing the portal ring beam (3); an outer ring steel plate (2-1) is pre-buried on the end face of the shaft wall (2) facing the portal ring beam (3); one end of the bolt hole (6) is fixedly connected to the end face of the shaft wall (2); The inner ring steel plate (1-1) is fixed on the inner ring steel plate (1-1), and the inner ring steel plate (1-1) is connected to the tunnel gate ring beam (3) through a connecting bolt (4); a wedge-shaped notch (10) is provided on the side of the shaft wall (2) facing the flexible filling layer (9), and the wedge-shaped notch (10) is filled with a flexible filling material (11); a plurality of rows of connecting anchor bars (5) connected to the tunnel gate ring beam (3) are provided on the outer ring steel plate (2-1); and the inner diameter of the bolt hole (6) is larger than the outer diameter of the connecting bolt (4).

2. The shield tunnel segment structure and shaft connection node according to claim 1, characterized in that: A first waterproof strip (7) is provided at a connection portion between the tunnel portal ring beam (3) and the segment structure (1).

3. The shield tunnel segment structure and shaft connection node according to claim 1, characterized in that: A second waterproof strip (8) is provided at the connection portion between the tunnel portal ring beam (3) and the shaft wall (2).

4. The shield tunnel segment structure and shaft connection node according to claim 1, characterized in that: The tunnel gate ring beam (3) is cast in situ using steel fiber reinforced concrete.

5. A construction method for a shield tunnel segment structure and a shaft connection node as claimed in any one of claims 1 to 4, characterized in that: The steps include: S1. Carry out the construction of the vertical shaft and prepare the pre-embedded outer ring steel plate (2-1) and the reserved wedge-shaped notch (10) according to the design requirements; S2. Carry out shield tunnel construction and pre-embed the inner ring steel plate (1-1) according to the design requirements; S3, mounting bolt hole (6); S4, installing shaft wall connecting anchor bars (5); S5, cleaning the debris in the remaining gap between the segment structure (1) and the hole in the shaft wall, and installing a flexible filling layer (9); S6, installing a flexible filling material (11) in the wedge-shaped notch (10) outside the hole in the shaft wall; S7, installing a first waterproof strip (7) at the connection position between the tunnel gate ring beam (3) and the segment structure (1); S8, installing a second waterproof strip (8) at the connection between the tunnel gate ring beam (3) and the shaft wall (2); S9, casting the portal ring beam (3) and curing it to the designed strength; S10, install the connecting bolts (4); S11. Complete the construction.

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