Tunnel secondary lining steel bar prefabricated structure and construction method

Abstract

The invention relates to the technical field of tunnel construction, and discloses a tunnel secondary lining steel bar prefabricated structure and a construction method.The tunnel secondary lining steel bar prefabricated structure comprises arch unit steel bars, side wall unit steel bars and inverted arch unit steel bars, and the side wall unit steel bars comprise first module steel bar components oppositely arranged at the two ends of the inverted arch unit steel bars; the first module steel bar component is divided into a putting-in section, a normal section and an inserting section from top to bottom. Through modular design, the secondary lining steel bar structure is prefabricated in a factory and then transported to a construction site to be quickly assembled, the workload and labor intensity of manual steel bar binding on site are reduced, the mounting efficiency of secondary lining steel bars is effectively improved, and the construction operation intensity is reduced; the putting-in section and the inserting section of the first module reinforcing steel bar component are engaged together in a socket matching mode to form stable connection, and the strength of the inserting position of the second lining reinforcing steel bar is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction, and in particular to a tunnel secondary lining steel bar prefabricated structure and a construction method. Background Art

[0002] The secondary lining of a tunnel is the only part of the tunnel structure that is exposed to the outside. It not only ensures the stability of the tunnel structure, but also bears the heavy responsibility of the tunnel's appearance. The surrounding rock with good location conditions is basically stable after the initial support. At this time, the secondary lining serves as a safety reserve and is generally a plain concrete structure. It is difficult to ensure the long-term stability of the structure of a poor surrounding rock section after the initial support. The secondary lining is required to provide support to ensure the stability of the tunnel structure. At this time, the secondary lining is a reinforced concrete structure. At present, the secondary lining steel bars of tunnels are generally manually tied on site, which is labor-intensive and takes a long time to complete. Therefore, how to quickly and efficiently lay the secondary lining steel bars of tunnels is a technical problem that needs to be solved urgently by technicians in this field. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention adopts a technical solution to solve the technical problems: a tunnel secondary lining steel bar prefabricated structure, including arch unit steel bars, side wall unit steel bars and inverted arch unit steel bars, the side wall unit steel bars include a first module steel bar component relatively arranged at both ends of the inverted arch unit steel bars, the first module steel bar component is divided into an insertion section, a normal section and an insertion section from top to bottom.

[0004] Preferably, the normal section includes a longitudinal main reinforcement, and a plurality of annular connecting reinforcements are sleeved on the outer side of the longitudinal main reinforcement along the length direction. The insertion section and the insertion section are engaged together and connected by means of a socket fit.

[0005] Preferably, the center angle of the arc line where the arch unit reinforcement is located is 144°, and the center angle of the arc line where the first module reinforcement member is located is 35°53′55″.

[0006] Preferably, the inverted arch unit reinforcement includes an arch bottom module reinforcement component and an arch foot module reinforcement component.

[0007] Preferably, an end of the arch foot module reinforcement member away from the arch bottom module reinforcement member is provided with an inserting section, and the inserting section cooperates with the insertion section of the first module reinforcement member.

[0008] Preferably, the center angle of the arc line where the reinforcement member of the arch bottom module is located is 32°37′, and the center angle of the arc line where the reinforcement member of the arch foot module is located is 55°.

[0009] The invention also discloses a construction method of a tunnel secondary lining steel bar prefabricated structure, comprising the following steps:

[0010] S1. Design the secondary lining steel prefabricated structure according to the tunnel diameter and the structural divisions of the vault, side wall and invert;

[0011] S2. Processing and shaping the arch unit steel bars, side wall unit steel bars and invert unit steel bars, and the actual bending degree of each unit steel bar is coordinated with the tunnel;

[0012] S3. Hoist the inverted arch unit steel bars into the inverted arch foundation pit for assembly to form a single inverted arch section. Position the inverted arch section, install the side wall unit steel bars on both sides of the inverted arch unit steel bars to form a side wall section, install the arch unit steel bars between the side wall unit steel bars, and leave a 1.5m area on the arch top to tie and weld the steel bars on site to form a full ring of secondary lining steel bars.

[0013] Preferably, in S2, the length of the arc in which the arch unit steel bar, the side wall unit steel bar and the inverted arch unit steel bar are located is calculated as follows: L=πR|α| / 180, wherein R is the radius and α is the center angle.

[0014] Preferably, the radius is calculated as follows:

[0015] R1=w / 2,

[0016] R2=R1-dcscβ,

[0017] R3=asec{arctan[(h-R1-e) / a+arccos(ψ1 / ψ2)},

[0018] Where w is the internal net width of the secondary lining (m), h is the internal net height of the secondary lining (m), t is the thickness of the secondary lining, and e is the rise of the secondary lining invert.

[0019] Preferably, in S3, before installing the inverted arch unit reinforcement, it is necessary to perform measurement and layout to determine the end positions on both sides of the inverted arch section.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. Through modular design, the secondary lining steel bar structure is prefabricated in the factory and then transported to the construction site for rapid assembly, reducing the workload and labor intensity of on-site manual steel bar binding, effectively improving the installation efficiency of the secondary lining steel bars and reducing the intensity of construction operations; the placement section and the insertion section of the steel bar component of the first module are engaged together in a socket-and-spigot manner to form a stable connection, effectively improving the strength of the secondary lining steel bar insertion point.

[0022] 2. Each unit of steel bars is processed centrally and can only be transported to the site for use after passing the factory acceptance, which greatly improves the pass rate of various steel bar inspection items and the accuracy of steel bar construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the present invention;

[0024] Figure 2 It is a structural schematic diagram of the first module steel bar component in the present invention;

[0025] Figure 3 It is a structural schematic diagram of the inverted arch unit steel bar in the present invention;

[0026] Figure 4 It is the tunnel section division diagram in the present invention.

[0027] In the figure: 1. Arch unit steel bar; 2. Side wall unit steel bar; 21. First module steel bar component; 211. Placement section; 212. Normal section; 213. Insertion section; 3. Inverted arch unit steel bar; 31. Arch bottom module steel bar component; 32. Arch foot module steel bar component. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0029] Prefabricated assembled secondary lining steel bars are assembled in a certain way from several unit steel bars. For the prefabricated secondary lining of the tunnel constructed by the drilling and blasting method, the division of units is affected by factors such as the production, transportation, hanging and assembly of prefabricated steel bars. From the perspective of the convenience of production, transportation, hanging and assembly of prefabricated steel bars, when the tunnel full ring secondary lining adopts more blocks, the mass of each prefabricated steel bar is small, but there are more lining joints after the prefabricated steel bars are assembled, which will inevitably increase the difficulty of waterproofing the secondary lining; if a smaller number of blocks is used, although there are fewer tunnel lining joints after assembly, which is conducive to the waterproofing of the tunnel lining, the mass of a single prefabricated steel bar is large, which will bring difficulties to the processing, transportation and assembly of the prefabricated steel bars. Therefore, the division of the number of prefabricated steel bars for the tunnel secondary lining should be considered in combination with multiple factors such as the net width, the convenience of production, transportation and hanging of prefabricated steel bars, and waterproof performance.

[0030] like Figure 1-3 As shown, a tunnel secondary lining steel prefabricated structure is mainly composed of arch unit steel bars 1, side wall unit steel bars 2 and inverted arch unit steel bars 3. The side wall unit steel bars 2 include first module steel bar components 21 relatively arranged at both ends of the inverted arch unit steel bars 3. The first module steel bar components 21 are divided from top to bottom into 211, a normal section 212 and an inserted section 213, wherein the normal section 212 includes longitudinal main bars, and a plurality of annular connecting bars are sleeved on the outer side of the longitudinal main bars along the length direction. The inserted section 211 and the inserted section 213 are engaged together and connected by a socket-and-spigot fit.

[0031] The inverted arch unit reinforcement 3 includes an arch bottom module reinforcement component 31 and an arch foot module reinforcement component 32. The arch foot module reinforcement component 32 is arranged at both ends of the arch bottom module reinforcement component 31, and an insertion section is provided at one end of the arch foot module reinforcement component 32 away from the arch bottom module reinforcement component 31, and the insertion section cooperates with the insertion section 213 of the first module reinforcement component 21.

[0032] The center angle of the arc line where the arch unit steel bar 1 is located is 144°, the center angle of the arc line where the first module steel bar component 21 is located is 35°53′55″, the center angle of the arc line where the arch bottom module steel bar component 31 is located is 32°37′, and the center angle of the arc line where the arch foot module steel bar component 32 is located is 55°.

[0033] A construction method for a tunnel secondary lining steel prefabricated structure comprises the following steps:

[0034] S1. Design the secondary lining steel prefabricated structure according to the tunnel diameter and the structural divisions of the vault, side wall and invert;

[0035] S2, processing and shaping the arch unit steel bar 1, the side wall unit steel bar 2 and the inverted arch unit steel bar 3, and the actual bending degree of each unit steel bar is matched with the tunnel;

[0036] S3, hoist the inverted arch unit steel bars 3 into the inverted arch foundation pit for assembly to form a single inverted arch section, position the inverted arch section, install the side wall unit steel bars 2 on both sides of the inverted arch unit steel bars 3 to form a side wall section, install the arch unit steel bars 1 between the side wall unit steel bars 2, and leave a 1.5m area on the arch top to tie and weld the steel bars on site to form a full ring of secondary lining steel bars.

[0037] In S3, before installing the inverted arch unit reinforcement 3, it is necessary to perform measurement and layout to determine the end positions on both sides of the inverted arch section.

[0038] Refer to the prefabricated segment division method of shield tunnel, and according to the cross-sectional characteristics of the secondary lining, such as Figure 4 As shown in the figure, the full ring secondary lining is divided into six steel module sections based on the tunnel centerline. Except for the 1.5-meter arch crown, the single-side arch + side wall area is divided into two steel module sections, and the invert area is divided into two steel module sections. The purpose of such block division is to reduce the number and difficulty of processing prefabricated steel bar molds as much as possible, facilitate on-site assembly of prefabricated steel bars and reduce the project cost. Only one set of molds is needed to process the arch unit steel bar 1, the side wall unit steel bar 2, and the invert unit steel bar 3, so the total number of molds for processing prefabricated structures is 3 sets.

[0039] The inner contour of the cross section of the secondary lining of the tunnel is composed of tangent arcs with four centers and their corresponding radii; the length of the arcs where the arch unit steel bar 1, the side wall unit steel bar 2 and the invert unit steel bar 3 are located is calculated as follows: L = πR|α| / 180, where R is the radius and α is the center angle;

[0040] The radius is calculated as:

[0041] R1=w / 2,

[0042] R2=R1-dcscβ,

[0043] R3=asec{arctan[(h-R1-e) / a+arccos(ψ1 / ψ2)},

[0044] Where: ψ1=R 2 1+a 2 +(h-R1-e)-2R1dcscβ;ψ2=2(R1-dcscβ)√[(h-R1-e) 2 +a 2 ]; w is the internal clear width of the secondary lining (m), h is the internal clear height of the secondary lining (m), t is the thickness of the secondary lining, e is the rise of the secondary lining invert, and a is the width of the tunnel construction limit.

[0045] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field and related fields without creative work should fall within the scope of protection of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention are implemented according to the conventional means in the field unless otherwise specified and limited.

Claims

1. A tunnel secondary lining steel prefabricated structure, characterized in that: The invention comprises an arch unit steel bar (1), a side wall unit steel bar (2) and an inverted arch unit steel bar (3); the side wall unit steel bar (2) comprises a first module steel bar component (21) arranged at two ends of the inverted arch unit steel bar (3); the first module steel bar component (21) is divided from top to bottom into an insertion section (211), a normal section (212) and an insertion section (213).

2. A tunnel secondary lining steel prefabricated structure according to claim 1, characterized in that: The normal section (212) comprises a longitudinal main rib, and a plurality of annular connecting ribs are sleeved on the outer side of the longitudinal main rib along the length direction. The insertion section (211) and the insertion section (213) are engaged together and connected in a socket-and-spigot fit.

3. A tunnel secondary lining steel prefabricated structure according to claim 1, characterized in that: The center angle of the arc line where the arch unit steel bar (1) is located is 144°, and the center angle of the arc line where the first module steel bar component (21) is located is 35°53′55″.

4. The tunnel secondary lining steel prefabricated structure according to claim 1, characterized in that: The inverted arch unit reinforcement (3) comprises an arch bottom module reinforcement component (31) and an arch foot module reinforcement component (32).

5. A tunnel secondary lining steel prefabricated structure according to claim 4, characterized in that: An end of the arch foot module reinforcement member (32) away from the arch bottom module reinforcement member (31) is provided with an inserting section, and the inserting section cooperates with the insertion section (213) of the first module reinforcement member (21).

6. A tunnel secondary lining steel prefabricated structure according to claim 4 or 5, characterized in that: The center angle of the arc line where the arch bottom module reinforcement member (31) is located is 32°37′, and the center angle of the arc line where the arch foot module reinforcement member (32) is located is 55°.

7. A construction method for the tunnel secondary lining steel prefabricated structure according to claim 1, characterized in that: The following steps are involved: S1. Design the secondary lining steel prefabricated structure according to the tunnel diameter and the structural divisions of the vault, side wall and invert; S2, processing and shaping the arch unit steel bars (1), the side wall unit steel bars (2) and the inverted arch unit steel bars (3), and the actual bending degree of each unit steel bar is matched with the tunnel; S3, hoisting the inverted arch unit steel bars (3) into the inverted arch foundation pit for assembly to form a single inverted arch section, positioning the inverted arch section, installing the side wall unit steel bars (2) on both sides of the inverted arch unit steel bars (3) to form a side wall section, installing the arch unit steel bars (1) between the side wall unit steel bars (2), and leaving a 1.5m area on the arch top to tie and weld the steel bars on site to form a complete ring of secondary lining steel bars.

8. The construction method of a tunnel secondary lining steel prefabricated structure according to claim 7, characterized in that: In S2, the length of the arcs of the arch unit reinforcement (1), the side wall unit reinforcement (2) and the inverted arch unit reinforcement (3) is calculated as: L = πR|α| / 180, where R is the radius and α is the center angle.

9. The construction method of a tunnel secondary lining steel prefabricated structure according to claim 8, characterized in that: The radius is calculated as: R1=w / 2, R2=R1-dcscβ, R3=asec{arctan[(h-R1-e) / a+arccos(ψ1 / ψ2)}, Where w is the internal net width of the secondary lining (m), h is the internal net height of the secondary lining (m), t is the thickness of the secondary lining, and e is the rise of the secondary lining invert.

10. The construction method of a tunnel secondary lining steel prefabricated structure according to claim 7, characterized in that: In S3, before installing the inverted arch unit reinforcement (3), it is necessary to carry out measurement and layout to determine the end positions on both sides of the inverted arch section.

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