Prefabricated double-layer segment structure

Abstract

The present invention belongs to the field of underground engineering, and in particular, relates to a superimposed prefabricated double-layer segment structure, including three interconnected standard blocks, a connection block A, a connection block B, and a wedge-shaped top block; the segment includes a UHPC protective layer and an ordinary concrete layer, and the segments are connected through longitudinally reserved screw holes and installation holes reserved on the segments. The UHPC protective layer and the ordinary concrete layer are superimposed and prefabricated. During the prefabrication process, the UHPC protective layer is used as a superimposed plate and superimposed with the ordinary concrete layer cast thereon to form a double-layer segment. The UHPC protective layer is configured with stress-bearing steel bars and truss steel grids to ensure the stress performance of the arc segment and the reliability of the interlayer connection. The outer side of the UHPC protective layer does not need to be waterproof. The advantages of the present invention are that the superimposed prefabricated double-layer segment is used to strengthen the reliability of the bonding between the UHPC layer and the concrete layer, avoid the interlayer stress concentration caused by the initial self-shrinkage of the UHPC material, save materials, have good economic effects, reduce the dead weight of the segment, facilitate transportation, and enhance the anti-seepage and corrosion resistance of the segment structure.

Description

Technical Field

[0001] The invention belongs to the field of underground engineering, and in particular relates to a superimposed prefabricated double-layer pipe segment structure. Background Art

[0002] Segment lining structures are often used in underground space projects, especially when shield construction is used. However, with the rapid development of cities, the utilization rate of ground space is getting lower and lower, and the development of underground space has become a new trend in urban construction. In recent years, major cities in China have built subways and integrated pipelines, and tunnels are often excavated in transportation to ensure the normal operation of cities and transportation. The use of shield machines has also increased, and the utilization rate of segment lining has increased accordingly. Ordinary concrete segments have high requirements for anti-seepage, especially in special areas such as corrosive groundwater and surrounding soil. Leakage of ordinary concrete segments has become a problem in the construction and later maintenance and operation process. Leakage of tunnel segments is very common, and it is difficult to repair and reinforce them in the later stage, which has a great impact on the applicability and safety of the structure. The current technologies mainly include adding anti-seepage admixtures to ordinary concrete, but the effect is not ideal, or paving and spraying additional waterproof layers, which increase the workload and difficulty of work and cannot meet the requirements of long-term anti-seepage, and require frequent maintenance and reinforcement.

[0003] Ultra-High Performance Concrete (UHPC) originated in Denmark in the 1970s. It has a history of more than 40 years of research and development. In recent years, it has also been valued and applied in various industries. It is known as the most innovative cement-based engineering material in the past 30 years. Its excellent mechanical properties, high durability, anti-seepage and anti-corrosion, and low carbon emissions are far ahead of ordinary concrete in the field of building materials. UHPC is the most durable engineering material. The mechanical properties of UHPC with proper reinforcement are close to those of steel structures. At the same time, UHPC has excellent wear resistance and explosion resistance. At present, domestic research and application are concentrated in the field of bridges. For example, steel-UHPC bridge structures have developed well in recent years, but they are less used in other fields. One important reason is that their cost is too high. Summary of the invention

[0004] In order to solve the above-mentioned technical problems, the present invention provides a laminated prefabricated double-layer segment structure, which mainly develops a laminated prefabricated double-layer segment structure, strengthens the reliability of the interface bonding between the UHPC layer and the concrete layer, avoids the interlayer stress concentration caused by the initial self-shrinkage of the UHPC material, saves the high-cost UHPC material and steel bars, has good economic effect, is convenient for construction, reduces the dead weight of the segment, facilitates transportation, and enhances the anti-seepage and corrosion resistance of the segment structure.

[0005] The technical solution adopted by the present invention is as follows: the superimposed prefabricated double-layer segment structure includes three interconnected standard blocks, a connecting block A, a connecting block B, and a wedge-shaped top block; the segment lining block is composed of an outer UHPC protective layer and an inner ordinary concrete layer; the UHPC protective layer is close to the ordinary concrete layer; screw holes are evenly distributed on the ordinary concrete layer, and adjacent standard blocks, connecting blocks A, connecting blocks B, and wedge-shaped top blocks are fastened and connected by connecting bolts passing through the screw holes; the UHPC protective layer includes stress-bearing steel bars a and part of truss steel bars, and the ordinary concrete layer includes stress-bearing steel bars b and part of truss steel bars; the UHPC protective layer and the ordinary concrete layer are tightly connected together through a truss-stress-bearing steel bar grid formed by stress-bearing steel bars a, stress-bearing steel bars b, and truss steel bars.

[0006] Furthermore, the arc center angle of the standard block is 72°, the arc center angles of the connecting block A and the connecting block B are 64.5°, and the arc center angle of the wedge-shaped top block is 15°.

[0007] Furthermore, mounting holes are provided on the standard block, the connection block A, the connection block B, and the wedge-shaped top block; a connection block A overlap edge is provided on the outside of the connection block A, a connection block B overlap edge is provided on the outside of the connection block B, and a top block left overlap edge and a top block right overlap edge are provided on both sides of the wedge-shaped top block; wherein the angle shape of the connection block A overlap edge corresponds to the left overlap edge of the top block, and the angle shape of the connection block B overlap edge corresponds to the right overlap edge of the top block;

[0008] Furthermore, the thickness of the UHPC protective layer is less than or equal to the thickness of the ordinary concrete layer;

[0009] Furthermore, waterproof sealing pads are provided at the joints of the three standard blocks, the connection block A, the connection block B, and the wedge-shaped top block; and no additional waterproof treatment is performed on the outer side of the UHPC protective layer;

[0010] Furthermore, when the reinforcing fibers added to the UHPC protective layer are steel fibers, no other steel bars are arranged therein except the stress-bearing steel bars a and the truss steel bars.

[0011] Furthermore, the segments are longitudinally connected with staggered overlaps, and during the assembly process, the wedge-shaped top blocks are always located on both sides of the central axis of the segment structure.

[0012] Furthermore, the UHPC protective layer and the ordinary concrete layer are both prefabricated components.

[0013] Furthermore, the prefabrication method of the UHPC protective layer and the ordinary concrete layer is as follows: first, the steel bars in the UHPC protective layer, namely the stress steel bars a and the truss steel bars, are tied and connected, and the above two kinds of steel bars are evenly and equidistantly arranged along the length direction of the pipe segment; after the steel bars are tied, the ultra-high performance concrete in the UHPC protective layer is poured, and after the pouring is completed, a part of the truss steel bars should be exposed to the outside of the UHPC protective layer; the UHPC protective layer is subjected to high-temperature steam curing for not less than 48 hours, and the temperature should be controlled at about 90°C. During the steam curing process, the exposed truss steel bars are protected by wrapping with a waterproof film or spraying with appropriate anti-corrosion materials; during the prefabrication process of the UHPC protective layer, the shrinkage amount is monitored, and after the initial self-shrinkage of the ultra-high performance concrete poured by the UHPC protective layer is basically completed and the strength reaches the requirements, the ordinary concrete layer is poured in a superimposed form, at which time the UHPC protective layer plays the role of a superimposed bottom plate, and correspondingly, the ordinary concrete layer should be poured after the side formwork is supported on both sides thereof, and an appropriate amount of expansion agent is added during the pouring process to control the shrinkage of the ordinary concrete; after the pouring is completed, the whole is cured until the strength requirements are met before it can be shipped.

[0014] Beneficial effects of the present invention:

[0015] The effects and advantages of the present invention are: the use of superimposed prefabricated double-layer segments strengthens the reliability of the interface bonding between the UHPC layer and the concrete layer, avoids the interlayer stress concentration caused by the initial self-shrinkage of the UHPC material, saves the high-cost UHPC material and steel bars, has good economic effect, is convenient for construction, reduces the dead weight of the segments, facilitates transportation, and enhances the anti-seepage and corrosion resistance of the segment structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall plane of the pipe segment of the present invention;

[0017] Figure 2 This is the overall reinforcement diagram of the segment structure;

[0018] Figure 3 It is a schematic diagram of the connection between segments;

[0019] Figure 4 It is the top view of the standard block;

[0020] Figure 5 It is a top view of the connection block A;

[0021] Figure 6 It is a top view of the connection block B;

[0022] Figure 7 It is a top view of the wedge-shaped top block;

[0023] Figure 8 This is the front view of the standard block;

[0024] Fig. 9It is the front view of the connection block A;

[0025] Fig.10 It is the front view of the connection block B;

[0026] Fig.11 It is the front view of the wedge-shaped top block;

[0027] Fig.12 This is the reinforcement diagram for the UHPC protective layer;

[0028] Fig.13 Enlarge the image of the reinforcement detail

[0029] Fig.14 This is the expanded view of the longitudinal connection of the pipe segment.

[0030] In the figure, 1 is a standard block; 2 is a connection block A; 2-1 is the lap edge of the connection block A; 3 is a connection block B; 3-1 is the lap edge of the connection block B; 4 is a wedge-shaped top block; 4-1 is the left lap edge of the top block; 4-2 is the right lap edge of the top block; 5 is the UHPC protective layer; 6 is the ordinary concrete layer; 7 is a screw hole; 8 is the stress-bearing steel bar a; 9 is the stress-bearing steel bar b; 10 is the truss steel bar; and 11 is the installation hole. DETAILED DESCRIPTION

[0031] In order to further illustrate the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0032] Example: Figure 1-13As shown: the present invention comprises three interconnected standard blocks 1, a connection block A2, a connection block B3, and a wedge-shaped top block 4; the segment lining blocks are all composed of an outer UHPC protective layer 5 and an inner ordinary concrete layer 6; the UHPC protective layer 5 is close to the ordinary concrete layer 6; screw holes 7 are evenly distributed on the ordinary concrete layer 6, and the adjacent standard blocks 1, connection blocks A2, connection blocks B3, and wedge-shaped top blocks 4 are fastened and connected by connecting bolts passing through the screw holes 7; the UHPC protective layer 5 includes stress-bearing steel bars a8 and part of the truss steel bars 10, The ordinary concrete layer includes stress-bearing steel bars b9 and part of truss steel bars 10; the UHPC protective layer 5 and the ordinary concrete layer 6 are tightly connected together by a truss-stress-bearing steel bar grid formed by stress-bearing steel bars a8, stress-bearing steel bars b9 and truss steel bars 10; the UHPC protective layer 5 and the ordinary concrete layer 6 are both prefabricated components, and the prefabrication method is as follows: firstly, the steel bars in the UHPC protective layer, namely the stress-bearing steel bars a8 and the truss steel bars 10, are tied and connected, and the above two kinds of steel bars are evenly and equidistantly arranged along the length direction of the pipe segment; after the steel bars are tied, After the UHPC protective layer is formed, the ultra-high performance concrete in the UHPC protective layer is poured. After the pouring is completed, a part of the truss steel bar 10 should be exposed to the outside of the UHPC protective layer 5; the UHPC protective layer 5 is subjected to high-temperature steam curing for not less than 48 hours, and the temperature should be controlled at about 90°C. During the steam curing process, the exposed truss steel bars are protected by wrapping with a waterproof film or spraying with appropriate anti-corrosion materials; during the prefabrication process of the UHPC protective layer 5, the shrinkage amount is monitored, and the initial self-shrinkage of the ultra-high performance concrete poured in the UHPC protective layer 5 is basically completed and the strength reaches the required After the calculation, the ordinary concrete layer 6 is cast in the form of superposition. At this time, the UHPC protective layer 5 plays the role of the superposition bottom plate. Correspondingly, the side formwork should be supported on both sides of the ordinary concrete layer 6, and an appropriate amount of expansion agent should be added during the casting process to control the shrinkage of the ordinary concrete; after the casting is completed, the whole is cured until the strength requirements are met before it can be shipped; in the prefabrication superposition process, the reserved screw holes and installation holes should be reserved; the arc center angle of the standard block 1 is 72°, the arc center angle of the connection block A2 and the connection block B3 is 64.5°, and the arc center angle of the wedge-shaped top block 4 is 15°;

[0033] like Figure 4-11 As shown: the standard block 1, the connection block A2, the connection block B3, and the wedge-shaped top block 4 are provided with mounting holes 11, the connection block A overlap edge 2-1 is provided on the outer side of the connection block A2, the connection block B overlap edge 3-1 is provided on the outer side of the connection block B3, and the left overlap edge 4-1 and the right overlap edge 4-2 of the top block are provided on both sides of the wedge-shaped top block 4; wherein the overlap edge 2-1 of the connection block A corresponds to the angle shape of the left overlap edge 4-1 of the top block, and the overlap edge 3-1 of the connection block B corresponds to the angle shape of the right overlap edge 4-2 of the top block;

[0034] The thickness of the UHPC protective layer 5 is less than or equal to the thickness of the ordinary concrete layer 6; in this embodiment, taking the thickness of a 300mm segment as an example, the thickness of the UHPC protective layer 5 can be 120mm, and the thickness of the ordinary concrete layer 6 can be 180mm. At this time, the overall deadweight of each segment can be reduced by 10% to 15% compared with the full ordinary concrete segment, achieving more convenient transportation and assembly, and the proportion of its deadweight reduction has basically no effect on the anti-floating of the segment structure by deadweight; preferably, when the thickness of the UHPC protective layer 5 is equal to that of the ordinary concrete layer 6, the deadweight of the segment is the lowest, the force effect and the anti-seepage and anti-corrosion effect are the best, and the overall cost may be increased accordingly;

[0035] Waterproof sealing pads are provided at the joints of the three standard blocks 1, the connection block A2, the connection block B3, and the wedge-shaped top block 4; no additional waterproofing treatment is performed on the outside of the UHPC protective layer 5; when the reinforcing fiber added to the UHPC protective layer 5 is steel fiber, no other steel bars are configured therein except the stress-bearing steel bars a8 and the truss steel bars 10; due to the super strong impermeability and anti-corrosion performance of the UHPC material, the UHPC material is directly used as a waterproof material and a stress-bearing material without additional waterproofing treatment, and the impermeability and compactness of the UHPC itself are used to resist the infiltration of groundwater, and the tensile and compressive performance of the UHPC with steel fibers is greatly improved compared with ordinary concrete, and the crack resistance is also enhanced, and the configuration of ordinary stress-bearing steel bars is sufficient to resist the external forces caused by the settlement and soil pressure of the pipe segment, so the reinforcement is reduced to achieve excellent economic effects;

[0036] like Fig.14 As shown: the segments are longitudinally connected with staggered overlaps, and during the assembly process, the wedge-shaped top blocks 4 are always located on both sides of the central axis of the segment structure.

[0037] In particular, considering that the UHPC material has a large initial self-shrinkage, the present invention can only use the UHPC material as the superimposed formwork layer in the prefabrication process, and during the production process, it should be cured with high-temperature steam at 90°C for not less than 48 hours before demolding, and the self-shrinkage of the ultra-high performance concrete material should be monitored during the prefabrication process, and the concrete of the ordinary concrete layer 6 can be poured only after the initial rapid self-shrinkage is basically completed; after the UHPC protective layer 5 is poured, the inner side does not need to be plastered, and the ordinary concrete layer 6 on it is superimposed with a natural rough surface; considering the possibility of interlayer shedding and displacement between the UHPC protective layer 5 and the ordinary concrete layer 6 of the pipe segment, the stress steel bars a8 and the truss steel bars 10 are arranged evenly along the length direction of the pipe segment, and when the thickness of the selected UHPC protective layer 5 is too thin and the ordinary concrete layer 6 is very thick and has a large deadweight, it is preferred to penetrate the ordinary concrete layer 6 with concrete nails and extend them into the UHPC protective layer 5 to enhance the reliability of the interlayer connection. In this embodiment, the thickness ratio of the two layers is 2:3, and the deadweight of the ordinary concrete layer is not large, so only the stress steel bars a8 and the truss steel grid 10 are configured.

[0038] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. The prefabricated double-layer segment structure is characterized by: The invention comprises three interconnected standard blocks (1), a connection block A (2), a connection block B (3), and a wedge-shaped top block (4); the segment lining block comprises an outer UHPC protective layer (5) and an inner ordinary concrete layer (6); the UHPC protective layer (5) is in close contact with the ordinary concrete layer (6); screw holes (7) are evenly distributed on the ordinary concrete layer (6); adjacent standard blocks (1), connection blocks A (2), connection blocks B (3), and wedge-shaped top blocks (4) are fastened and connected by connecting bolts passing through the screw holes (7); the UHPC protective layer (5) comprises stress-bearing steel bars a (8) and part of truss steel bars (10), and the ordinary concrete layer comprises stress-bearing steel bars b (9) and part of truss steel bars (10); the UHPC protective layer (5) and the ordinary concrete layer (6) are tightly connected together by a truss-stress-bearing steel bar grid formed by the stress-bearing steel bars a (8), the stress-bearing steel bars b (9), and the truss steel bars (10); The arc center angle of the standard block (1) is 72°, the arc center angles of the connecting block A (2) and the connecting block B (3) are 64.5°, and the arc center angle of the wedge-shaped top block (4) is 15°; The standard block (1), the connection block A (2), the connection block B (3), and the wedge-shaped top block (4) are provided with mounting holes (11); the connection block A lap edge (2-1) is provided on the outside of the connection block A (2); the connection block B lap edge (3-1) is provided on the outside of the connection block B (3); and the wedge-shaped top block (4) is provided with a top block left lap edge (4-1) and a top block right lap edge (4-2) on both sides; wherein the connection block A lap edge (2-1) corresponds to the left lap edge (4-1) of the top block, and the connection block B lap edge (3-1) corresponds to the right lap edge (4-2) of the top block.

2. The laminated prefabricated double-layer segment structure according to claim 1 is characterized in that: The thickness of the UHPC protective layer (5) is less than or equal to the thickness of the ordinary concrete layer (6).

3. The laminated prefabricated double-layer segment structure according to claim 1 is characterized in that: Waterproof sealing pads are provided at the joints of the three standard blocks (1), the connection block A (2), the connection block B (3), and the wedge-shaped top block (4); and no additional waterproofing treatment is performed on the outside of the UHPC protective layer (5).

4. The laminated prefabricated double-layer segment structure according to claim 1 is characterized in that: When the reinforcing fibers added to the UHPC protective layer (5) are steel fibers, no other steel bars are arranged therein except for the stress-bearing steel bars a (8) and the truss steel bars (10).

5. The laminated prefabricated double-layer segment structure according to claim 1 is characterized in that: The segments are overlapped with staggered seams when connected longitudinally, and during the assembly process, the wedge-shaped top blocks (4) are always located on both sides of the central axis of the segment structure.

6. The laminated prefabricated double-layer segment structure according to claim 1, characterized in that: The UHPC protective layer (5) and the ordinary concrete layer (6) are both prefabricated components.

7. The laminated prefabricated double-layer segment structure according to claim 6 is characterized in that: The prefabrication method of the UHPC protective layer (5) and the ordinary concrete layer (6) is as follows: firstly, the steel bars in the UHPC protective layer, namely the load-bearing steel bars a (8) and the truss steel bars (10) are tied and connected, and the above two kinds of steel bars are evenly and equidistantly arranged along the length direction of the pipe segment; after the steel bars are tied, the ultra-high performance concrete in the UHPC protective layer is poured, and after the pouring is completed, a part of the truss steel bars (10) should be exposed to the outside of the UHPC protective layer (5); the UHPC protective layer (5) is subjected to high-temperature steam curing for not less than 48 hours, and the temperature should be controlled at about 90°C. During the steam curing process, the exposed truss steel bars are The steel bars are protected by wrapping with a waterproof membrane or spraying with an appropriate anti-corrosion material. During the prefabrication process of the UHPC protective layer (5), the shrinkage is monitored. After the initial self-shrinkage of the ultra-high performance concrete cast by the UHPC protective layer (5) is basically completed and the strength reaches the required level, the ordinary concrete layer (6) is cast in a superimposed manner. At this time, the UHPC protective layer (5) plays the role of a superimposed bottom plate. Accordingly, side formworks should be supported on both sides of the UHPC protective layer before the ordinary concrete layer (6) is cast. During the casting process, an appropriate amount of expansion agent is added to control the shrinkage of the ordinary concrete. After the casting is completed, the entire structure is cured until the strength requirements are met before it can be shipped out of the factory.

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