A shield segment and tunnel bottom structure connecting assembly and a construction method thereof

Abstract

This invention relates to the field of shield tunneling technology, and more particularly to a connection component and construction method for shield tunnel segments and tunnel floor structure, comprising: steel plates; steel bars; and self-compacting concrete. This invention uses steel plates and steel bars, along with self-compacting concrete, to firmly bond them to the tunnel floor structure and tunnel segments as a whole. The horizontal sliding load of the tunnel floor structure first acts on the self-compacting concrete, then is transferred to the steel plates and steel bars through the "U"-shaped bonding interface, and finally transferred to the shield tunnel segments by the steel plates and steel bars. This effectively transforms complex loads into interface shear stress, fully utilizing material properties and exhibiting significantly superior anti-slip capability compared to traditional connection methods. Furthermore, it fully utilizes the existing longitudinal joints, pre-embedded grouting sleeves, and assembly positioning holes of the shield tunnel segments. The steel plates are inserted into the longitudinal joints, and the steel bars are embedded in the pre-embedded grouting sleeves and / or assembly positioning holes, eliminating the need for additional drilling or rebar installation on the tunnel segments, thus maximizing the protection of the integrity and waterproofing performance of the tunnel segment structure.

Description

Technical Field

[0001] This invention relates to the field of shield tunnel technology, and in particular to a connection component between shield tunnel segments and tunnel bottom structure and its construction method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Currently, the construction methods for shield tunnel bottom structures, both domestically and internationally, are mainly divided into three types based on differences in construction technology: integral cast-in-place, partial prefabrication + cast-in-place combination, and integral prefabrication. Among these, integral cast-in-place construction, due to its low level of mechanization, complex construction organization and coordination, and difficulty in quality control, has been gradually phased out by the market. While partial prefabrication + cast-in-place combination has improved construction technology and work efficiency to some extent, it still requires a large amount of on-site rebar tying and concrete pouring, which not only limits further improvement in construction efficiency but also adversely affects the health of construction workers due to dust and noise generated by wet work. Integral prefabrication, using factory-prefabricated components, demonstrates significant advantages in terms of high-efficiency construction and environmental protection—it can effectively avoid quality defects such as honeycomb and pitting that are prone to occur in cast-in-place construction, and can also significantly shorten the on-site construction period and reduce construction waste and dust pollution. Therefore, it has broad application prospects in the construction of shield tunnel bottom structures.

[0004] However, current shield tunnel floor structure construction technology has significant shortcomings in structural connection design: connecting bolts are only installed between adjacent floor structures, while no rigid connection device is installed between the shield segments and the floor structure. Flexible connection is achieved solely by filling the gap between them with self-compacting concrete. During construction, this connection method is highly susceptible to displacement deviations in the floor structure due to dynamic loads such as the passage of segment transport vehicles and the mechanical assembly of the floor structure. In extreme cases, it may even lead to instability of the floor structure, seriously affecting tunnel construction safety and subsequent operational reliability. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned shortcomings by providing a shield tunnel segment and tunnel bottom structure connection assembly and its construction method.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a shield tunnel segment and tunnel bottom structure connection assembly, comprising: A steel plate is placed at the longitudinal joint between two circumferentially assembled segments, and the upper end of the steel plate does not contact the bottom surface of the tunnel floor structure. A steel bar is embedded in the pre-embedded grouting sleeve or assembly positioning hole of the bottom segment, and the end of the steel bar maintains a gap with the tunnel bottom structure. Self-compacting concrete is used to backfill the gap between the bottom segment and the tunnel floor structure and tightly wrap the three sides of the steel plate and / or the steel bar to form a "U"-shaped wrapping and bonding. The steel plate, the steel bar, and the solidified self-compacting concrete form an integral bonded structure. The horizontal sliding load generated by the tunnel bottom structure is sequentially transferred to the tunnel segment through the self-compacting concrete, the steel plate, and / or the steel bar. The bonding effect between the self-compacting concrete and the steel plate and / or the steel bar is used to convert it into interfacial shear stress, which restricts the sliding displacement of the tunnel bottom structure within the cross section of the shield tunnel.

[0007] Furthermore, a rubber sealing gasket is provided at the longitudinal seam for connecting the two circumferentially assembled segments. The thickness of the steel plate matches the size of the longitudinal seam, and the steel plate and the rubber sealing gasket do not contact each other.

[0008] Furthermore, a rubber isolation pad is pre-installed at one end of the steel plate within the longitudinal seam. The rubber isolation pad is a polytetrafluoroethylene sheet or a nitrile rubber pad layer.

[0009] Furthermore, the steel rod adopts a cylindrical structure, and the diameter of the steel rod matches the size of the pre-embedded grouting sleeve or the assembly positioning hole. The length of the steel rod at the pre-embedded grouting sleeve is inconsistent with that at the assembly positioning hole.

[0010] Furthermore, both the steel plate and the steel bar have an anti-corrosion layer on their outer surfaces. The anti-corrosion layer is either a galvanized layer or an epoxy primer layer, wherein the thickness of the galvanized layer is not less than 85 μm.

[0011] A construction method employing a shield tunnel segment and tunnel floor structure connection assembly specifically includes the following steps: Step 1: Complete the assembly of the tunnel lining segments; Step 2: Place the steel plate at the longitudinal joint of the segment and embed the steel rod into the pre-embedded grouting sleeve or assembly positioning hole of the segment; Step 3: Assemble the tunnel floor structure, ensuring that the bottom surface of the tunnel floor structure does not directly contact the steel plates and steel bars; Step 4: Backfill and inject self-compacting concrete into the gap between the tunnel segments and the tunnel floor structure through the reserved grouting holes.

[0012] The steel plate, the steel bar, and the solidified self-compacting concrete form an integral bonded structure, which restricts the sliding displacement of the tunnel bottom structure within the cross-section of the shield tunnel.

[0013] Furthermore, in step four, the self-compacting concrete fills all the gaps between the steel plate, the steel bar, and the tunnel floor structure, forming a continuous force transmission medium.

[0014] Furthermore, the design bond strength between the steel plate and the self-compacting concrete... Determine using the following formula:

[0015] In the formula, This refers to the standard value of the compressive strength of self-compacting concrete cubes. The surface treatment coefficient for steel plates is 1.0 to 1.2 for galvanizing or epoxy treatment. This is the width-to-thickness ratio coefficient of the steel plate; it is taken as 1.0 when the width-to-thickness ratio is ≥8. The concrete restraint factor is 1.2 for three-sided wrapping.

[0016] Furthermore, the steel rod is secured using an adhesive method: The steel bar is bonded and anchored to the pre-embedded grouting sleeve or the assembly positioning hole through the self-compacting concrete, and its ultimate pull-out bearing capacity is... The calculation is as follows:

[0017] In the formula, The interfacial bond strength between the steel rod and the grouting material is taken as 3.0~5.0 MPa; The diameter of the steel bar For effective embedding length.

[0018] Furthermore, the anti-slip ultimate bearing capacity of the connecting component The calculation is as follows:

[0019] In the formula, For the effective bonding area of ​​the steel plate, according to calculate, The length of the steel plate The width of the steel plate. The thickness of the steel plate; This refers to the number of steel bars; The shear-drawing conversion factor for the steel bar is taken as 0.5~0.7; and it satisfies the following conditions: ,in, This represents the design value for the horizontal sliding load on the tunnel floor structure. For safety factors, the serviceability limit state is taken as 1.5, and the ultimate limit state is taken as 2.0~2.5.

[0020] The beneficial effects of this invention are reflected in: This invention uses steel plates and steel bars, along with self-compacting concrete, to firmly bond them to the tunnel floor structure and tunnel segments as a whole. The horizontal sliding load of the tunnel floor structure first acts on the self-compacting concrete, then is transferred to the steel plates and steel bars through the "U"-shaped bonding interface, and finally transferred to the tunnel segments by the steel plates and steel bars. This effectively transforms complex loads into interfacial shear stress, fully utilizing material properties and exhibiting significantly superior anti-slip capability compared to traditional connection methods. Furthermore, it fully utilizes the existing longitudinal joints, pre-embedded grouting sleeves, and assembly positioning holes of the tunnel segments. The steel plates are inserted into the longitudinal joints, and the steel bars are embedded in the pre-embedded grouting sleeves and / or assembly positioning holes, eliminating the need for additional drilling or rebar installation on the segments and maximizing the protection of the segment structure's integrity and waterproofing performance. Attached Figure Description

[0021] Figure 1 This is an overall schematic diagram of an embodiment of the present invention; Figure 2 This is a side view of a steel plate connection in one embodiment of the present invention; Figure 3 This is a side view of the steel bar connection in one embodiment of the present invention; Figure 4 This is a connection view of the steel plates in one embodiment of the present invention; Figure 5 This is a connection view of the steel bars in one embodiment of the present invention.

[0022] In the picture: 1. Steel plate; 2. Steel bar; 3. Segment; 4. Tunnel floor structure; 5. Self-compacting concrete; 6. Longitudinal joint; 7. Pre-embedded grouting sleeve; 8. Assembly positioning hole. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1-5 The present invention discloses a connection component between a shield tunnel segment and a tunnel bottom structure, including a steel plate 1 and a steel bar 2, which achieves a strong connection function through the synergistic effect of the self-compacting concrete 5 backfilled in the gap cavity formed by the shield tunnel segment 3 and the tunnel bottom structure 4.

[0025] The steel plate 1 is made of Q355B steel, with a length ranging from 1.5m to 1.8m, a width of 72.55mm, and a thickness ranging from 8mm to 10mm. Its overall dimensions match the dimensions of the longitudinal joint 6 of the tunnel segment 3. In practical applications, the dimensions of the steel plate 1 can be further adjusted according to specific requirements, and its width design must be strictly controlled: on the one hand, it must be avoided from being too wide and directly contacting the tunnel floor structure 4 to prevent interference with the assembly operation of the tunnel floor structure 4; on the other hand, it must avoid contact with the rubber sealing gasket at the longitudinal joint 6 between the two circumferentially assembled tunnel segments 3 to prevent adverse effects on the waterproof performance of the shield tunnel joint.

[0026] Further, a 2mm thick polytetrafluoroethylene sheet is pre-attached as a rubber isolation pad at one end of the steel plate 1 inserted into the longitudinal seam 6. Before embedding steel plate 1, special anti-corrosion treatment is required. Galvanizing (zinc layer thickness ≥ 85μm) or applying epoxy primer can effectively prevent steel plate 1 from rusting and ensure the long-term durability of the structure.

[0027] The steel bar 2 adopts a cylindrical structure with a diameter ranging from 6mm to 10mm, which matches the size of the pre-embedded grouting sleeve 7 or the assembly positioning hole 8 of the pipe segment 3 located at the bottom.

[0028] It should be noted that the length of steel bar 2 should be selected appropriately to avoid direct contact with the tunnel bottom structure 4, so as to prevent the tunnel bottom structure 4 from being unable to be assembled properly due to interference. Further optimization means that the steel rod 2 at the pre-embedded grouting sleeve 7 can be of different lengths from the steel plate 1 at the assembly positioning hole 8, so as to more accurately match the size for embedding and installation; The surface of steel bar 2 can be galvanized (zinc layer thickness ≥85μm) or coated with epoxy primer to prevent rust from affecting the structural connection performance and ensure long-term reliability.

[0029] The self-compacting concrete 5 has a strength grade of C40 and exhibits good fluidity, filling properties, and micro-expansion. Its standard value for cubic compressive strength is... It is 40 MPa.

[0030] In practice, steel plate 1 is inserted into the longitudinal joint 6 between the two circumferentially assembled segments 3, and EPDM rubber sealing gaskets are placed inside the longitudinal joint 6 for waterproofing. When self-compacting concrete 5 is backfilled into the cavity between segment 3 and tunnel floor structure 4, it tightly wraps the three sides of steel plate 1 and / or steel rod 2, forming a "U"-shaped wrapping bond. After solidification, a reliable bond is formed between steel plate 1 and / or steel rod 2 and self-compacting concrete 5, generating shear resistance through the bond. At this time, the horizontal sliding load generated by tunnel floor structure 4 is sequentially transferred to segment 3 through self-compacting concrete 5, steel plate 1 and / or steel rod 2, and converted into interfacial shear stress through the bond between self-compacting concrete 5 and steel plate 1 and / or steel rod 2, limiting the sliding displacement of tunnel floor structure 4 in the cross section of shield tunnel.

[0031] A construction method Step 1: Construct the tunnel segment 3 according to the conventional shield tunneling method, ensure that the tunnel segment 3 is in good position, that there is no misalignment in the longitudinal joint 6, and embed a rubber sealing gasket at the longitudinal joint 6.

[0032] Step two: Inside the tunnel, insert the processed steel plates 1 one by one into the circumferential longitudinal joints 6 of the segment 3 to make them stable and upright. At the same time, insert the steel rods 2 one by one into the pre-embedded grouting sleeves 7 and assembly positioning holes 8 at the bottom of the segment 3 arch.

[0033] Step 3: Hoist and assemble the precast tunnel bottom structure 4 (such as a precast box culvert). During the assembly process, strictly control the installation accuracy of the tunnel bottom structure 4 to ensure that its bottom surface does not directly contact the top of the steel plate 1 and the steel bar 2, leaving a gap of about 15-20mm to provide space for subsequent grouting.

[0034] Step four: Inject self-compacting concrete 5 between the tunnel bottom structure 4 and the segment 3, through the grouting holes reserved at the top of both ends of the tunnel bottom structure 4. During grouting, use a bottom-up, continuous grouting method until all gaps are completely filled, and confirm that the steel plate 1 and steel rod 2 are tightly wrapped by the self-compacting concrete 5 from the bottom and sides, forming a "U" shape or a completely wrapped state. After the self-compacting concrete 5 has solidified, complete the assembly of the connecting components.

[0035] Further optimization explains the bond strength between the steel plate 1 and the self-compacting concrete 5. :

[0036] In the formula, The standard value of the 5-cubic-meter compressive strength of self-compacting concrete is taken as 40 MPa. For steel plate 1, the surface treatment coefficient is 1.1 for galvanizing or 1.0 for epoxy treatment; The width-to-thickness ratio coefficient of steel plate 1 is taken as 1.0 when the width-to-thickness ratio is ≥8; The concrete restraint factor is 1.2 for three-sided wrapping.

[0037] The steel bar 2 is bonded and anchored to the pre-embedded grouting sleeve 7 or the assembled positioning hole 8 by self-compacting concrete 5, and its ultimate pull-out bearing capacity :

[0038] In the formula, The interfacial bond strength between steel rod 2 and grouting material is taken as 4.0 MPa; For a steel bar with a diameter of 2, For the effective embedding length, the average value of the embedding lengths of multiple steel bars 2 is taken.

[0039] Ultimate slip resistance of connecting components :

[0040] In the formula, For the effective bonding area of ​​steel plate 1, according to calculate, For the length of steel plate 1, For the width of the steel plate 1, The thickness of the steel plate is 1. The quantity of steel bars 2; The shear-drawing conversion factor for steel bar 2 is 0.6.

[0041] The design value for the horizontal sliding load of the tunnel bottom structure is set at 1500 kN. For safety, a factor of 2.0 is used under the ultimate limit state of bearing capacity.

[0042] Calculated This connecting component can effectively transfer loads and limit the horizontal displacement of the tunnel bottom structure 4 within the shield tunnel.

[0043] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0044] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0045] Additionally, "multiple" refers to two or more.

[0046] 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 principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A connection assembly between shield tunnel segments and tunnel floor structure, characterized in that, include: A steel plate (1) is placed at the longitudinal joint (6) between two circumferentially assembled segments (3), and the upper end of the steel plate (1) does not contact the bottom surface of the tunnel bottom structure (4); The steel rod (2) is embedded in the pre-embedded grouting sleeve (7) or the assembly positioning hole (8) of the bottom segment (3), and the end of the steel rod (2) maintains a gap with the tunnel bottom structure (4); Self-compacting concrete (5) is backfilled in the gap between the bottom segment (3) and the tunnel bottom structure (4) and tightly wraps the three sides of the steel plate (1) and / or the steel bar (2) to form a "U" shaped wrapping bond; The steel plate (1), the steel rod (2), and the solidified self-compacting concrete (5) form an integral bonded structure. The horizontal sliding load generated by the tunnel bottom structure (4) is sequentially transferred to the segment (3) through the self-compacting concrete (5), the steel plate (1), and / or the steel rod (2). The bonding effect between the self-compacting concrete (5) and the steel plate (1) and / or the steel rod (2) is converted into interface shear stress, which restricts the sliding displacement of the tunnel bottom structure (4) in the cross section of the shield tunnel.

2. The shield tunnel segment and tunnel floor structure connection assembly according to claim 1, characterized in that: A rubber sealing gasket is provided at the longitudinal seam (6) for connecting the two circumferentially assembled segments (3). The thickness of the steel plate (1) matches the size of the longitudinal seam (6), and the steel plate (1) and the rubber sealing gasket do not contact each other.

3. The shield tunnel segment and tunnel floor structure connection assembly according to claim 2, characterized in that: A rubber isolation pad is pre-installed on one end of the steel plate (1) within the longitudinal seam (6). The rubber isolation pad is a polytetrafluoroethylene sheet or a nitrile rubber pad layer.

4. The shield tunnel segment and tunnel floor structure connection assembly according to claim 1, characterized in that: The steel rod (2) adopts a cylindrical structure, and the diameter of the steel rod (2) matches the size of the pre-embedded grouting sleeve (7) or the assembly positioning hole (8). The length of the steel rod (2) at the pre-embedded grouting sleeve (7) is inconsistent with that at the assembly positioning hole (8).

5. The shield tunnel segment and tunnel floor structure connection assembly according to claim 1, characterized in that: The outer surfaces of the steel plate (1) and the steel bar (2) are provided with an anti-corrosion layer, which is a galvanized layer or an epoxy primer layer, wherein the thickness of the galvanized layer is not less than 85μm.

6. A construction method, employing a shield tunnel segment and tunnel floor structure connection assembly as described in claims 1-5, characterized in that, Specifically, the following steps are included: Step 1: Complete the assembly of the shield tunnel segments (3); Step 2: Place the steel plate (1) at the longitudinal joint (6) of the segment (3), and embed the steel rod (2) into the pre-embedded grouting sleeve (7) or the assembly positioning hole (8) of the segment (3); Step 3: Assemble the tunnel bottom structure (4) and ensure that the bottom surface of the tunnel bottom structure (4) does not directly contact the steel plate (1) and steel bar (2); Step 4: Backfill and grout the gap between the segment (3) and the tunnel bottom structure (4) through the reserved grouting holes and inject self-compacting concrete (5). The steel plate (1), the steel rod (2), and the solidified self-compacting concrete (5) form an integral bonded structure, which restricts the sliding displacement of the tunnel bottom structure (4) within the cross section of the shield tunnel.

7. A construction method according to claim 6, characterized in that: In step four, the self-compacting concrete (5) fills all the gaps between the steel plate (1), the steel rod (2) and the tunnel bottom structure (4) to form a continuous force transmission medium.

8. A construction method according to claim 6, characterized in that, Design bond strength between the steel plate (1) and the self-compacting concrete (5) Determine using the following formula: In the formula, The standard value of the cubic compressive strength of self-compacting concrete (5) is given. The surface treatment coefficient for steel plate (1) is 1.0~1.2 for galvanizing or epoxy treatment; The width-to-thickness ratio coefficient of the steel plate (1) is 1.0 when the width-to-thickness ratio is ≥8; The concrete restraint factor is 1.2 for three-sided wrapping.

9. A construction method according to claim 8, characterized in that, The steel rod (2) is secured by an adhesive bonding method: The steel bar (2) is bonded and anchored to the pre-embedded grouting sleeve (7) or the assembly positioning hole (8) through the self-compacting concrete (5), and its ultimate pull-out bearing capacity is... The calculation is as follows: In the formula, The interfacial bonding strength between the steel rod (2) and the grouting material is taken as 3.0~5.0MPa; The diameter of the steel bar (2) is... For effective embedding length.

10. A construction method according to claim 9, characterized in that, The ultimate anti-slip bearing capacity of the connecting component The calculation is as follows: In the formula, For the effective bonding area of ​​steel plate (1), according to calculate, The length of the steel plate (1) is... The width of the steel plate (1) is... The thickness of the steel plate (1); The number of steel bars (2); The shear-drawing conversion factor for the steel bar (2) is taken as 0.5~0.7; and satisfies the following conditions: ,in, The design value of the horizontal sliding load of the tunnel bottom structure (4) is given. For safety factors, the serviceability limit state is taken as 1.5, and the ultimate limit state is taken as 2.0~2.5.

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