Bottom backfill construction method for curved components inside large shield tunnels

Abstract

The present application discloses a bottom backfill construction method for an internal curved member of a large shield tunnel. First, a bottom formwork is installed between the bottom of the curved member and the tunnel segment, and the middle part of the leveling layer is poured. Then, a ditch box formwork is installed above the middle part of the leveling layer, an end formwork is set on the side of the curved member, and filling material is poured through the discharge hole at the top of the curved member to form a backfill layer; a plug formwork is set on the windows on both sides of the bottom of the curved member; finally, through the grouting holes reserved on both sides of the bottom of the curved member and the cable groove gaps on both sides of the curved member, concrete is poured between the curved member and the tunnel segment to form the two side parts of the leveling layer, and finally a bottom backfill structure of the curved member is formed; the present application uses the bottom formwork, the end formwork and the plug formwork to cast concrete between the curved member and the tunnel segment to construct the leveling layer and the backfill layer, thereby improving the connection tightness between the curved member and the tunnel segment.

Description

Technical Field

[0001] The present application relates to the technical field of shield tunnel construction, and in particular to a bottom backfill construction method for arc-shaped components inside a large shield tunnel. Background Art

[0002] With the rapid development of modern urban construction and the increase in population, surface transportation can no longer fully meet people's daily travel needs. Expanding and utilizing underground space to alleviate urban volume and traffic pressure is an inevitable trend. The shield tunneling method has been widely promoted and applied in urban subway construction due to its rapid construction speed and minimal impact on the ground.

[0003] The internal structure of a tunnel includes curved components and intermediate partition walls. The curved components are located at the bottom of the tunnel, adjacent to the pipe segments, and are a crucial component of the prefabricated tunnel's internal structure. After the curved components are transported to the installation work surface inside the tunnel, they must be positioned and assembled with the installed adjacent curved components in a certain posture. Curved components are large structural components characterized by large dimensions, heavy weight, and high installation precision. The quality of their installation directly affects the installation of other structures above them. Their upper portion, used to install structures such as intermediate partition walls, must withstand significant stress. Existing curved components are connected to tunnel segments solely through bolts. This connection is not strong, posing certain safety risks. Therefore, there is an urgent need to improve the tightness of the connection between curved components and tunnel segments during the installation and construction of the tunnel's internal structure.

[0004] The information disclosed in this background technology section is only used to deepen the understanding of the background technology of the present disclosure and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0005] After long-term tunnel construction practice, the inventors found that the existing large shield tunnel internal arc components and tunnel segments are only connected by bolts. This connection is not firm and poses a safety hazard to the tunnel structure. However, the backbuilding construction method can improve the connection tightness between the arc components and the tunnel segments.

[0006] In view of at least one of the above technical problems, the present disclosure provides a bottom backfill construction method for the internal curved components of a large shield tunnel, by applying a leveling layer and a backfill layer between the bottom of the internal curved components and the tunnel segments, thereby improving the connection tightness between the curved components and the tunnel segments.

[0007] According to one aspect of the present disclosure, a method for backfilling the bottom of an internal curved member of a large shield tunnel is provided, comprising the following steps:

[0008] (1) Install the bottom formwork between the bottom of the curved member and the tunnel segment, and pour concrete through the reserved feed hole at the top of the curved member to form the middle part of the leveling layer;

[0009] (2) Installing a gutter box template above the middle portion of the leveling layer; and pouring filler material through the reserved feed hole on the top of the arc-shaped member to form a backfill layer;

[0010] (3) Plug templates are installed on the windows on both sides of the bottom of the arc-shaped member to block the windows, and end templates are installed on the sides of the arc-shaped member;

[0011] (4) Casting is performed between the arc-shaped member and the tunnel segment through the reserved grouting holes on both sides of the bottom of the arc-shaped member and the cable groove gaps on both sides of the arc-shaped member to form the two side portions of the leveling layer, and finally forming the bottom backfill structure of the arc-shaped member;

[0012] The bottom backfill structure includes the leveling layer arranged in the gap between the bottom of the arc-shaped component and the tunnel segment, and the backfill layer arranged above the window at the bottom of the arc-shaped component. The leveling layer is a C40 concrete layer, and the backfill layer is a C30 concrete layer. A groove for drainage is opened on one side of the backfill layer.

[0013] The leveling layer includes a middle layer cast on the bottom formwork and side layers located on both sides of the middle layer and cast below the plugging formwork.

[0014] In some embodiments of the present disclosure, the bottom template is an inflated arc-shaped airbag, which includes an airbag body and an inflation end arranged on the airbag body. The inflation end is equipped with a pressure gauge. After inflation, the maximum diameter of the arc-shaped airbag is 10-18 cm, and its maximum inflation pressure is 0.01-0.05 MPa.

[0015] In some embodiments of the present disclosure, the plug template includes a first template and a second template connected to each other by a butterfly buckle, and the upper surfaces of the first template and the second template are both provided with a plurality of reinforcing ribs for enhancing the supporting strength;

[0016] The first template and the second template are both provided with a plurality of vibration openings for observation and the entry and exit of the vibrating rod, and the vibration openings are provided with covers to facilitate the opening and closing of the vibration openings;

[0017] The size of the vibration opening is 200*200 mm, and a plurality of air outlet holes are provided on the first template and / or the second template.

[0018] In some embodiments of the present disclosure, support rods are hingedly connected to the first template and the second template, and the support rods connect the template and the arc-shaped member to support the first template and the second template to ensure the tightness of the window sealing;

[0019] Rubber sealing strips are installed at the connection between the windows on both sides of the bottom of the arc-shaped component and the first and second templates to improve their tightness, so as to facilitate subsequent concrete pouring.

[0020] In some embodiments of the present disclosure, the thickness of the leveling layer is 6-10 cm; when installing the eighth ring arc-shaped component, the bottom backbuilding construction of the 1st to 5th ring arc-shaped components is carried out at the same time, and then the backbuilding construction is carried out once every five ring arc-shaped components are installed in sequence. The backbuilding construction is carried out in the form of a pump truck and a hopper.

[0021] In some embodiments of the present disclosure, in step (2), one cutting hole is reserved for each installation of a five-ring arc-shaped component. The diameter of the cutting hole is 145-160 mm and is reserved at the top center position of the middle arc-shaped component.

[0022] In some embodiments of the present disclosure, in step (4), when pouring between the arc-shaped member and the tunnel segment, the pouring condition is observed through the vibrating port, and if bubbles are found, the vibrating rod is used to vibrate in time through the vibrating port;

[0023] The vibrating rod is a small-diameter vibrating rod with a diameter of less than 35 cm to ensure uniform and dense vibration.

[0024] In some embodiments of the present disclosure, the concrete poured in the leveling layer and backfill layer should be quality controlled and slump tested to ensure that its slump expansion is 760-850mm, the filling coefficient is 1.05-1.1, and its T50 test expansion time is 2-5 seconds.

[0025] In some embodiments of the present disclosure, the end formwork includes a formwork body corresponding to the bottom backbuilding structure and a handle provided on the formwork body, and the material thereof is 5 mm thick steel plate.

[0026] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0027] 1. This application uses a bottom formwork, an end formwork, and a plug formwork to pour concrete between the arc-shaped member and the tunnel segment to form a leveling layer and a backfill layer. Therefore, the connection tightness between the arc-shaped member and the tunnel segment is improved, and the technical problem of the loose connection between the existing arc-shaped member and the tunnel segment is effectively solved.

[0028] 2. The bottom formwork of the present application adopts an arc-shaped airbag, which, after being inflated, has a certain curvature corresponding to the bottom curvature of the arc-shaped component, which is conducive to the pouring of concrete and further improves the connection tightness between the arc-shaped component and the tunnel segment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flow chart of a construction method in one embodiment of the present application.

[0030] Figure 2 This is a schematic structural diagram of the bottom backfill structure in a tunnel in one embodiment of the present application.

[0031] Figure 3 This is a structural diagram of the bottom backfill structure in one embodiment of the present application.

[0032] Figure 4 This is one of the structural schematic diagrams of the end template in one embodiment of the present application.

[0033] Figure 5 This is the second structural diagram of the plug template in one embodiment of the present application.

[0034] Figure 6 This is a schematic structural diagram of the end template in another embodiment of the present application.

[0035] In the above figures, 1 is the tunnel segment, 2 is the arc-shaped component, 3 is the bottom backfill structure, 31 is the backfill layer, 32 is the middle layer, 33 is the side layer, 4 is the cutting hole, 5 is the first formwork, 6 is the second formwork, 7 is the butterfly buckle, 8 is the support rod, 9 is the vibrating port, 91 is the cover, 51 is the exhaust hole, 11 is the formwork body, and 12 is the handle. DETAILED DESCRIPTION

[0036] Unless otherwise specified, the unit modules, components, structures, mechanisms and other devices involved in the following embodiments are conventional commercially available products.

[0037] The embodiment of the present application solves the technical problem of weak connection between existing arc components and tunnel segments by providing a bottom backfill construction method for arc components inside a large shield tunnel, and improves the connection tightness between the arc components and the tunnel segments by pouring concrete between the arc components of the tunnel internal structure and the tunnel segments.

[0038] The technical solution in the embodiment of the present application is to solve the technical problem of the loose connection between the above-mentioned existing arc-shaped components and the tunnel segments. The overall idea is as follows: first, a bottom template is installed between the bottom of the arc-shaped component and the tunnel segment, and a gutter box template is installed above the middle window at the bottom of the arc-shaped component, and an end template is set on the side of the arc-shaped component; then, filler is poured onto the gutter box template through the blanking hole reserved at the top of the arc-shaped component to form a backfill layer; and plug templates are set on the windows on both sides of the bottom of the arc-shaped component to seal the windows; finally, a leveling layer is poured between the arc-shaped component and the tunnel segment through the grouting holes reserved on both sides of the bottom of the arc-shaped component and the cable groove gaps on both sides of the arc-shaped component, thereby finally forming the bottom backfill structure of the arc-shaped component.

[0039] The above-mentioned bottom backfill structure includes the leveling layer arranged in the gap between the bottom of the arc-shaped component and the tunnel segment, and the backfill layer arranged above the bottom window of the arc-shaped component. The leveling layer is a C40 concrete layer, the backfill layer is a C30 concrete layer, and a groove is provided on one side of the backfill layer; the leveling layer includes an intermediate layer cast on the bottom formwork and side layers located on both sides of the intermediate layer and cast below the plug formwork.

[0040] The bottom backbuilding structure further improves the connection tightness between the arc-shaped components and the tunnel segments, effectively solving the technical problem of the weak connection between the existing arc-shaped components and the tunnel segments.

[0041] In order to better understand the technical solution of the present application, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0042] Example 1

[0043] This example discloses a method for backfilling the bottom of an internal arc-shaped component of a large shield tunnel. Figure 1 The general process is: install the bottom formwork - pour the middle layer of the leveling layer - install the ditch box formwork - pour the backfill layer - install the plug formwork and end formwork - pour the leveling layer and windows on both sides.

[0044] The specific steps include:

[0045] (1) A bottom formwork is installed between the bottom of the arc-shaped member 2 and the tunnel segment 1, and concrete is poured on the bottom formwork through the blanking hole reserved at the top of the arc-shaped member to form the middle part of the leveling layer, i.e., the middle layer. The bottom formwork is an inflated arc-shaped airbag, which includes an airbag body and an inflation end provided on the airbag body. A pressure gauge is installed on the inflation end. The air pressure in the airbag can be known at any time according to the indication of the pressure gauge to ensure that the maximum inflation pressure of the arc-shaped airbag after inflation is 0.01-0.05MPa, and the maximum diameter of the arc-shaped airbag is 10-18cm. Preferably, the maximum diameter of the arc-shaped airbag after inflation is 15cm. In addition, the wall thickness of the arc-shaped airbag can be selected according to construction needs.

[0046] (2) Install the gutter box template above the middle window at the bottom of the arc-shaped member 2, as shown in the figure. Figure 6 As shown, the end formwork includes a formwork body 11 corresponding to the bottom backbuilding structure 3 and a handle 12 provided on the formwork body 11, and the material thereof is a 5mm thick steel plate. Figure 2 As shown, the filling material is poured through the discharge hole 4 reserved at the top of the arc-shaped component 2 to form a backfill layer 31.

[0047] (3) A plug template is set up on the windows on both sides of the bottom of the arc-shaped member 2 to block the windows, and an end template is set on the side of the arc-shaped member 2; Figure 4 and 5 As shown, the plug template includes a first template 5 and a second template 6 connected to each other by a butterfly buckle 7. The upper surfaces of the first template 5 and the second template 6 are provided with a plurality of reinforcing ribs for enhancing the supporting strength. The setting of the reinforcing ribs can be set according to actual construction needs. The main purpose is to enhance the supporting strength of the first template 5 and the second template 6.

[0048] Furthermore, the first and second templates 5 and 6 are each provided with multiple vibration ports 9 for observation and the insertion and removal of vibrating rods. These ports are equipped with covers 91 to facilitate opening and closing. The vibration ports 9 measure 200 x 200 mm, and the first and / or second templates 5 and 6 are each provided with multiple air vents. Support rods 8 are hingedly connected to the first and second templates 5 and 6, connecting the templates to the curved member 2 to support the first and second templates 5 and 6, ensuring a tight seal between the windows. Rubber sealing strips are installed at the connection between the windows on both sides of the bottom of the curved member 2 and the first and second templates 5 and 6 to enhance their tightness, facilitating subsequent concrete pouring.

[0049] (4) Through the grouting holes reserved on both sides of the bottom of the arc-shaped member 2 and the cable groove gaps on both sides of the arc-shaped member 2, pouring is performed between the arc-shaped member 2 and the tunnel segment 1 to form the two side portions of the leveling layer, that is, the side layers, and finally form the bottom backfill structure 3 of the arc-shaped member 2; when pouring between the arc-shaped member 2 and the tunnel segment 1, the pouring situation is observed through the vibrating port 9. If bubbles are found, the vibrating rod is used to vibrate in time through the vibrating port 9. In addition, the vibrating rod is a small-diameter vibrating rod with a diameter of less than 35 cm to ensure uniform and dense vibration.

[0050] Furthermore, if Figure 3 As shown, the bottom backfill structure 3 includes the leveling layer arranged in the gap between the bottom of the arc-shaped member 2 and the tunnel segment 1, and the backfill layer 31 arranged above the bottom window of the arc-shaped member 2. The leveling layer is a C40 concrete layer, and the backfill layer 31 is a C30 concrete layer. A groove for collecting water and draining water is opened on one side of the backfill layer 31. The groove is formed by casting the ditch box template to facilitate drainage. In addition, the concrete cast in the leveling layer and the backfill layer 31 should be quality controlled and slump tested to ensure that its slump expansion is 760-850mm, the filling coefficient is 1.05-1.1, and its T50 test expansion time is 2-5 seconds, so as to ensure the quality of the concrete and improve its supporting strength.

[0051] Furthermore, the thickness of the leveling layer is 6-10 cm, preferably 8 cm. Those skilled in the art can select this thickness based on actual conditions during construction. When installing the eighth circular arc-shaped member 2, the bottom backfilling of the first to fifth circular arc-shaped members 2 is performed simultaneously. Subsequently, backfilling is performed for each fifth circular arc-shaped member 2 installed. Backfilling is performed using a pump truck and a hopper. A feed hole 4 is reserved for each fifth circular arc-shaped member 2 installed. The diameter of the feed hole 4 is 145-160 mm and is located at the top center of the intermediate circular arc-shaped member 2.

[0052] The leveling layer includes an intermediate layer 32 cast on the bottom formwork and side layers 33 cast below the plugging formwork on either side of the intermediate layer 32. The leveling layer and backfill layer 31 of the bottom backfill structure 3 further enhance the connection between the curved member 2 and the tunnel segment 1, effectively resolving the existing technical issue of a weak connection between the curved member 2 and the tunnel segment 1.

[0053] Although some preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0054] Obviously, those skilled in the art may make various modifications and variations to this application without departing from the spirit and scope of the invention. Thus, if such modifications and variations to the present invention fall within the scope of the claims of this application and their equivalents, this application is intended to include such modifications and variations.

Claims

1. A method for backfilling the bottom of an arc-shaped component inside a large shield tunnel, characterized in that: The steps include: (1) Install the bottom formwork between the bottom of the curved member and the tunnel segment, and pour concrete through the reserved feed hole at the top of the curved member to form the middle part of the leveling layer; (2) Installing a gutter box template above the middle portion of the leveling layer; The filling material is poured through the discharge hole reserved at the top of the arc-shaped component to form a backfill layer; (3) Plug templates are installed on the windows on both sides of the bottom of the arc-shaped member to block the windows, and end templates are installed on the sides of the arc-shaped member; (4) Casting is performed between the arc-shaped member and the tunnel segment through the reserved grouting holes on both sides of the bottom of the arc-shaped member and the cable groove gaps on both sides of the arc-shaped member to form the two side portions of the leveling layer, and finally forming the bottom backfill structure of the arc-shaped member; The bottom backfill structure includes the leveling layer arranged in the gap between the bottom of the arc-shaped component and the tunnel segment, and the backfill layer arranged above the window at the bottom of the arc-shaped component. The leveling layer is a C40 concrete layer, and the backfill layer is a C30 concrete layer. A groove for drainage is opened on one side of the backfill layer. The leveling layer includes a middle layer cast on the bottom formwork and side layers located on both sides of the middle layer and cast below the plugging formwork.

2. The bottom backfill construction method of the internal arc-shaped member of a large shield tunnel according to claim 1 is characterized in that: The bottom template is an inflated arc-shaped airbag, which includes an airbag body and an inflation end arranged on the airbag body. The inflation end is equipped with a pressure gauge. After inflation, the maximum diameter of the arc-shaped airbag is 10-18 cm, and its maximum inflation pressure is 0.01-0.05 MPa.

3. The bottom backfill construction method of the internal arc-shaped member of a large shield tunnel according to claim 1 is characterized in that: The plug template includes a first template and a second template connected to each other by a butterfly buckle, and the upper surfaces of the first template and the second template are both provided with a plurality of reinforcing ribs for enhancing the supporting strength; The first template and the second template are both provided with a plurality of vibration openings for observation and the entry and exit of the vibrating rod, and the vibration openings are provided with covers to facilitate the opening and closing of the vibration openings; The size of the vibration opening is 200*200 mm, and a plurality of air outlet holes are provided on the first template and / or the second template.

4. The bottom backfill construction method of the internal arc-shaped member of a large shield tunnel according to claim 3 is characterized in that: The first template and the second template are hinged with support rods, and the support rods connect the template and the arc-shaped member to support the first template and the second template to ensure the tightness of the window sealing; Rubber sealing strips are installed at the connection between the windows on both sides of the bottom of the arc-shaped component and the first and second templates to improve their tightness, so as to facilitate subsequent concrete pouring.

5. The bottom backfill construction method of the internal arc-shaped member of a large shield tunnel according to claim 1 is characterized in that: The thickness of the leveling layer is 6-10 cm; when installing the eighth ring arc-shaped component, the bottom backbuilding construction of the 1st to 5th ring arc-shaped components is carried out at the same time, and then the backbuilding construction is carried out once every five ring arc-shaped components are installed. The backbuilding construction is carried out in the form of a pump truck and a hopper.

6. The bottom backfill construction method of the internal arc-shaped member of a large shield tunnel according to claim 1 is characterized in that: In the step (2), a cutting hole is reserved for each installation of a five-ring arc-shaped component. The diameter of the cutting hole is 145-160 mm and is reserved at the top center position of the middle arc-shaped component.

7. The bottom backfill construction method of the internal arc-shaped member of a large shield tunnel according to claim 3 is characterized in that: In the step (4), when pouring between the arc-shaped member and the tunnel segment, the pouring condition is observed through the vibrating port. If bubbles are found, the vibrating rod is used to vibrate the structure in a timely manner through the vibrating port. The vibrating rod is a small-diameter vibrating rod with a diameter of less than 35 cm to ensure uniform and dense vibration.

8. The bottom backfill construction method of the internal arc-shaped member of a large shield tunnel according to claim 1 is characterized in that: The concrete poured in the leveling layer and backfill layer should be subjected to quality control and slump test to ensure that its slump expansion is 760-850mm, the filling coefficient is 1.05-1.1, and the T50 test expansion time is 2-5 seconds.

9. The bottom backfill construction method of the internal arc-shaped member of a large shield tunnel according to claim 1 is characterized in that: The end formwork includes a formwork body corresponding to the bottom backbuilding structure and a handle arranged on the formwork body, and the material of the end formwork is 5mm thick steel plate.

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