Coordinated crossing structure of new power tunnel under the influence of existing underground structures

Abstract

This invention discloses a collaborative crossing structure for new power tunnels under proximity interference from existing underground structures. The structure includes a proximity interference isolation pile foundation and a new power tunnel. The proximity interference isolation pile foundation comprises three pile caps located on both sides of the existing underground structure and elastic isolation layers. Each pile cap consists of three piles arranged in a triangle and a reinforced concrete cap positioned on top of the three piles. The elastic isolation layers are correspondingly positioned between the reinforced concrete caps and the existing underground structure. The new power tunnel comprises a box-shaped tunnel body, with both ends positioned on corresponding reinforced concrete caps. The tunnel walls are constructed of shrinkage-compensating concrete and contain prestressed steel strands. This invention reduces the impact of proximity interference on existing structures, ensures the operational safety of existing facilities, optimizes project scale, and simultaneously guarantees the stiffness, strength, and crack resistance of large-span tunnels, improving the crack resistance of new tunnels.

Description

Technical Field

[0001] This invention relates to the field of building technology, and in particular to a cooperative crossing structure for newly constructed power tunnels under proximity interference from existing underground structures. Background Technology

[0002] Currently, my country's urbanization has entered a new stage of three-dimensional intensive development of underground space. In some economically developed areas, the development level of underground space is high, and existing underground structures (such as subway tunnels, integrated utility tunnels, and existing underground passages) are distributed in a "three-dimensional interweaving" pattern. In the construction of new power tunnels, the new power tunnels are close to existing underground structures, which can easily lead to mutual influences such as deformation transmission and stress conflicts, and face the problem of close interference with the aforementioned existing underground structures. Secondly, for large-span power tunnels that need to cross existing underground structures by more than 25 meters, they must simultaneously bear the heavy vehicle loads of the upper road, the operating loads of the power tunnel, and the stress of their own structure. The traditional "thick wall + dense reinforcement" design is prone to resulting in excessively large project scale and difficulty in offsetting the tensile stress caused by the mid-span bending moment, which can easily lead to excessively wide through cracks, causing leakage and steel corrosion. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a collaborative crossing structure for new power tunnels under proximity interference from existing underground structures. This structure can reduce the impact of proximity interference on existing structures, ensure the operational safety of existing facilities, optimize the scale of structural engineering, and simultaneously ensure the stiffness, strength, and crack resistance of large-span tunnels, thereby improving the tunnel's crack resistance.

[0004] According to an embodiment of the present invention, a collaborative crossing structure for constructing a new power tunnel under proximity interference from an existing underground structure includes a proximity interference isolation type pile foundation and a new power tunnel. The proximity interference isolation type pile foundation includes three pile caps and elastic isolation layers disposed on both sides of the existing underground structure. The three pile caps include three piles arranged in a triangle and a reinforced concrete cap disposed on the upper end of the three piles. The upper end of the reinforced concrete cap protrudes relative to the existing underground structure. The elastic isolation layers are disposed one-to-one between the reinforced concrete caps and the existing underground structure. The new power tunnel includes a box-shaped tunnel body disposed on the proximity interference isolation type pile foundation. There is a gap between the box-shaped tunnel body and the existing underground structure. The two ends of the box-shaped tunnel body are disposed on corresponding reinforced concrete caps. The mid-span portion of the box-shaped tunnel body is pre-arched upward relative to the existing underground structure. The box-shaped tunnel body includes four rectangularly arranged and sequentially connected wall panels. The wall panels are made of shrinkage-compensating concrete with a strength greater than or equal to C40, and prestressed steel strands are provided inside the wall panels.

[0005] According to some embodiments of the present invention, the elastic isolation layer is configured as a modified rubber-concrete composite isolation layer.

[0006] According to some embodiments of the present invention, the prestressed steel strands are tensioned to 50% of the preset stress during the construction stage of the box-shaped tunnel body. After the box-shaped tunnel body and the proximity interference isolation pile foundation are stabilized under the stress, the prestressed steel strands are tensioned to 100% of the preset stress.

[0007] According to some embodiments of the present invention, the prestressed steel strands are steel strands with an outer diameter of 15.2 mm and a standard strength of 1860 MPa.

[0008] According to some embodiments of the present invention, the wall panel is provided with double-layer longitudinal reinforcement that cooperates with the prestressed steel strands to bear the force.

[0009] According to some embodiments of the present invention, the amount of expansive agent in the shrinkage-compensating concrete is 8% to 10%.

[0010] According to some embodiments of the present invention, a load transition section is provided between the reinforced concrete foundation and the wall panels on both sides of the box-shaped tunnel body.

[0011] According to some embodiments of the present invention, road load buffer and anti-sinking structures are provided on both sides of the top of the box-shaped tunnel body located within the road area.

[0012] According to some embodiments of the present invention, the road load buffer and anti-settlement structure includes a reinforced slab, a buffer cushion layer, and a wedge-shaped gradient corbel. The wedge-shaped gradient corbel is cast on the top of the box-shaped tunnel body. The reinforced slab is arranged above the wedge-shaped gradient corbel and protrudes outward. The buffer cushion layer is disposed below the reinforced slab and located outside the wedge-shaped gradient corbel.

[0013] According to some embodiments of the present invention, the reinforced slab is a reinforced concrete slab, the buffer cushion layer is a crushed stone cushion layer, and multiple layers of tar paper are provided between the reinforced slab, the wedge-shaped gradient corbel, and the box-shaped tunnel body.

[0014] The cooperative crossing structure for newly constructed power tunnels under proximity interference from existing underground structures, according to embodiments of the present invention, has at least the following beneficial effects: (1) Proximity interference control: Through the synergistic effect of the elastic isolation layer and the pile foundation, the maximum settlement and horizontal displacement of underground structures can be controlled, the impact of proximity interference on existing structures (such as subway operation and utility tunnel function) can be reduced, and the operational safety of existing facilities can be guaranteed.

[0015] (2) Optimization of the main structure of the tunnel: The main structure adopts a dual control system of prestressed concrete and high-strength shrinkage-compensating concrete, which reduces the wall thickness of the box structure and optimizes the scale of the project. At the same time, it ensures the stiffness, strength and crack resistance of the large-span tunnel under the dynamic load of the upper road, the operating load of the power tunnel and its own structural stress, improves the crack resistance level of the tunnel, improves the ability to withstand the impact of the dynamic load of heavy vehicles on the upper road, and has better long-term structural stability. (3) Road load adaptation: The coordinated design of the road load buffer and anti-settlement structure and the main body of the box tunnel realizes the smooth transmission of road load and coordinated control of settlement, diffuses vehicle load, protects the connection between the tunnel top and the roadbed, effectively buffers the differential settlement between the tunnel and the road foundation, and ensures road durability and driving comfort.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of a new power tunnel cooperative crossing structure under proximity interference from existing underground structures, according to an embodiment of the present invention. Figure 2 for Figure 1 Schematic diagram of the internal reinforcement of the main body of the medium-sized box-shaped tunnel; Figure 3 for Figure 2 Schematic diagram of the road load buffer and anti-settlement structure on the main body of the medium-sized box tunnel; Figure 4 for Figure 1 Schematic diagram of reinforcement details for reinforced concrete foundation caps; Figure 5 for Figure 1 Schematic diagram of the load transition section between the reinforced concrete foundation and the main body of the box tunnel.

[0018] Figure label: 110 Three-pile cap, 111 Pile foundation, 112 Reinforced concrete cap, 120 Elastic isolation layer, 130 Steel cable, 140 Elastic support block, 200 Box tunnel main body, 210 Wall panel, 211 Prestressed steel strand, 212 Double-layer longitudinal reinforcement, 220 Road load buffer and anti-settlement structure, 221 Reinforced slab, 222 Buffer cushion layer, 223 Wedge-shaped gradual corbel, 224 Asphalt felt, 230 Load transition section, 231 Longitudinal reinforcing rib, 300 Existing underground structure. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0020] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0021] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0022] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0023] Reference Figure 1 , Figure 2 and Figure 4According to an embodiment of the present invention, a new power tunnel collaborative crossing structure under proximity interference of an existing underground structure includes a proximity interference isolation type pile foundation and a new power tunnel. The proximity interference isolation type pile foundation includes three pile caps 110 disposed on both sides of the existing underground structure 300 and an elastic isolation layer 120. The three pile caps 110 include three piles 111 distributed in a triangle and a reinforced concrete cap 112 disposed on the upper end of the three piles 111 to form a support system with structural stability and less engineering work. The upper end of the reinforced concrete cap 112 protrudes relative to the existing underground structure 300. The elastic isolation layer 120 is disposed one-to-one between the reinforced concrete cap 112 and the existing underground structure 300. The elastic isolation layer 120 can absorb the impact during construction and operation. Vibration loads are applied to cut off the deformation transmission path between the new tunnel and the existing underground structure 300, so that the horizontal displacement of the existing underground structure 300 is controlled within ≤3mm. The new power tunnel includes a box-shaped tunnel body 200 set on a proximity interference isolation pile foundation. There is a gap between the box-shaped tunnel body 200 and the existing underground structure 300. The two ends of the box-shaped tunnel body 200 are set on corresponding reinforced concrete abutments 112. The mid-span of the box-shaped tunnel body 200 is pre-arched upward relative to the existing underground structure 300. The box-shaped tunnel body 200 includes four rectangular wall panels 210 connected in sequence. The wall panels 210 are made of shrinkage-compensating concrete with a strength greater than or equal to C40, and prestressed steel strands 211 are installed inside the wall panels 210.

[0024] In the specific implementation process, the reinforced concrete foundation 112 is double-reinforced in the form of equilateral triangles and rectangles, corresponding to the three piles 111 below, thus forming a triangular stable support; the piles 111 are cast-in-place piles with a diameter of 1.2m, and the length of the piles 111 meets the requirement of penetrating the underground soft soil layer to the moderately weathered rock layer, and the characteristic value of the vertical bearing capacity of a single pile is ≥5000kN.

[0025] The proposed invention, through the synergistic effect of an elastic isolation layer 120 and pile foundation, enables the construction of a new power tunnel crossing structure under proximity interference from existing underground structures. This achieves maximum settlement and horizontal displacement of the underground structures ≤3mm, far below the limits specified in the "Technical Specification for Safety Protection of Urban Rail Transit Structures," reducing the impact of proximity interference on existing structures such as subway operations and utility tunnels, and ensuring the operational safety of existing facilities. Simultaneously, the main structure employs a dual control system of prestressed concrete and high-strength shrinkage-compensating concrete. This reduces the wall thickness of the box-type structure, optimizes the project scale, and ensures the stiffness, strength, and crack resistance of the large-span tunnel under dynamic loads from the upper road, operational loads from the power tunnel, and its own structural stress. This improves the tunnel's crack resistance level, reduces mid-span deflection by more than 40% compared to conventional designs, enhances its ability to withstand the impact of dynamic loads from heavy vehicles on the upper road, and results in better long-term structural stability.

[0026] According to some embodiments of the present invention, the elastic isolation layer 120 is configured as a modified rubber-concrete composite isolation layer. The modified rubber-concrete composite isolation layer is formed by compounding modified rubber components with a concrete substrate according to a specific process. Physical / chemical modification is used to improve the compatibility between rubber and concrete. A three-stage process of "substrate preparation—composite molding—curing" is employed to uniformly disperse rubber particles in the concrete matrix, forming a composite structure of "rigid skeleton + elastic filler," ultimately achieving the functions of isolating vibration, absorbing deformation, and preventing crack propagation.

[0027] Of course, in other embodiments, the elastic isolation layer 120 may also be made of materials such as polyurethane elastomer concrete or high ductility fiber concrete.

[0028] According to some embodiments of the present invention, the prestressed steel strands 211 are tensioned to 50% of their preset stress during the construction stage of the box-shaped tunnel body 200. After the box-shaped tunnel body 200 and the adjacent interference isolation pile foundation have stabilized under the same stress, the prestressed steel strands 211 are then tensioned to 100% of their preset stress, with the prestress controlled at 0.5~0.7MPa. The prestressed steel strands 211 adopt a staged tensioning process, which can accurately control the prestress after the box-shaped tunnel is completed.

[0029] According to some embodiments of the present invention, the prestressed steel strand 211 is a steel strand with an outer diameter of 15.2 mm and a standard strength of 1860 MPa.

[0030] Reference Figure 2 In the main body 200 of the box tunnel, the prestressed steel strands 211 are arranged in the manner of "densification at mid-span and gradual change at both ends" - one strand is set every 200mm in the longitudinal direction of the bottom plate and one strand is set every 300mm in the side wall, and the tension control stress is 0.75fptk.

[0031] Reference Figure 2 According to some embodiments of the present invention, the wall panel 210 is provided with double-layer longitudinal ribs 212 that cooperate with the prestressed steel strands 211 to bear force, so as to form a main-auxiliary cooperative force system with the prestressed steel strands 211 and improve crack resistance.

[0032] According to some embodiments of the present invention, the expansion agent content of the shrinkage-compensating concrete is 8% to 10% to ensure that the strength and micro-expansion performance of the shrinkage-compensating concrete meet the requirements.

[0033] Reference Figure 1According to some embodiments of the present invention, the proximity interference isolation type pile foundation further includes steel cables 130 disposed between reinforced concrete pile caps 112 on both sides of the existing underground structure 300. Elastic support blocks 140 are installed at the mid-span of the steel cables 130, and the elastic support blocks 140 abut against the middle of the box-shaped tunnel body 200. The elastic support blocks 140 are spaced apart from the existing underground structure 300, and the steel cables 130 pass through the elastic isolation layer 120. Through this arrangement, a gap is left between the top of the existing underground structure 300 and the box-shaped tunnel body 200, eliminating the need for the existing underground structure 300 to support the newly constructed box-shaped tunnel body 200. The reinforced concrete pile caps 112 can utilize the steel cables 130 to provide mid-span elastic support for the box-shaped tunnel body 200, thereby controlling the mid-span deformation of the box-shaped tunnel body 200 and improving its crack resistance. In addition, the steel cable 130 can connect the reinforced concrete foundation 112 and the elastic isolation layer 120 together, which can prevent the elastic isolation layer 120 from settling relative to the reinforced concrete foundation 112, and can also transmit the vibration at the mid-span of the box tunnel body 200 to the elastic isolation layer 120 for absorption through the steel cable 130, thereby reducing the proximity interference between the existing underground structure 300 and the newly built box tunnel body 200.

[0034] Reference Figure 5 According to some embodiments of the present invention, a load transition section 230 is provided between the reinforced concrete foundation 112 and the two side wall panels 210 of the box-shaped tunnel body 200 to avoid stress abrupt changes between the reinforced concrete foundation 112 and the box-shaped tunnel body 200.

[0035] Reference Figure 5 In the specific implementation process, the load transition section 230 includes multiple longitudinal reinforcing ribs 231 arranged side by side. The longitudinal reinforcing ribs 231 are connected to the wall panels 210 on the side of the box-shaped tunnel body 200, and the lower end of the longitudinal reinforcing ribs 231 is connected to the reinforced concrete foundation 112.

[0036] Reference Figure 2 and Figure 3 According to some embodiments of the present invention, road load buffer and anti-settlement structures 220 are provided on both sides of the top of the box-shaped tunnel body 200 located within the road area. Thus, the coordinated design of the road load buffer and anti-settlement structures 220 and the box-shaped tunnel body enables smooth transmission of road loads and coordinated control of settlement, dissipates vehicle loads, protects the junction between the tunnel top and the roadbed, effectively buffers differential settlement between the tunnel and the road foundation, and ensures road durability and driving comfort.

[0037] Reference Figure 2 and Figure 3According to some embodiments of the present invention, the road load buffer and anti-settlement structure 220 includes a reinforced slab 221, a buffer cushion layer 222, and a wedge-shaped gradient corbel 223. The wedge-shaped gradient corbel 223 is cast on the top of the box-shaped tunnel body 200. The reinforced slab 221 is arranged above the wedge-shaped gradient corbel 223 and protrudes outward. The buffer cushion layer 222 is disposed below the reinforced slab 221 and located outside the wedge-shaped gradient corbel 223. Thus, the gradient design of the wedge-shaped gradient corbel 223 eliminates the abrupt change in stiffness between the box-shaped tunnel body 200 and the reinforced slab 221, making the load transfer path smoother. The road load can be transferred from the reinforced slab 221 to the wedge-shaped gradient corbel 223, and the road load is diffused and the minor settlement of the road is absorbed by the buffer cushion layer 222, ultimately achieving a differential settlement between the box-shaped tunnel body 200 and the road foundation ≤5mm.

[0038] According to some embodiments of the present invention, the reinforced slab 221 is a reinforced concrete slab to ensure the load-bearing capacity of the reinforced slab 221.

[0039] According to some embodiments of the present invention, the buffer layer 222 is a crushed stone layer, which has a certain buffering capacity and water absorption performance.

[0040] Reference Figure 2 and Figure 3 According to some embodiments of the present invention, multiple layers of tar paper 224 are provided between the reinforced slab 221, the wedge-shaped gradient corbel 223, and the box-shaped tunnel body 200, to further eliminate the abrupt change in stiffness between the box-shaped tunnel body 200 and the reinforced slab 221.

[0041] The collaborative crossing structure provided by this invention eliminates the need to reinforce existing underground structures 300, as well as the need for additional large-scale pile foundations 111 and grouting isolation layers. Compared with conventional construction methods, it saves 50% of the construction period and reduces construction costs by approximately 30%. The prestressed concrete with shrinkage compensation design reduces the frequency of tunnel leakage repairs, lowering the overall life-cycle operation and maintenance costs. The construction method of the collaborative crossing structure provided by this invention is compatible with mature methods such as open-cut and pile foundations 111, offering strong controllability. It can be directly applied to projects such as power tunnels and integrated utility tunnels in densely populated underground facilities areas, promoting the upgrading of intensive underground space development technology.

[0042] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A structure for a new power tunnel to cross over in coordination with an existing underground structure under the influence of close-by interference, characterized in that, include: The proximity interference isolation type pile foundation includes three pile caps (110) and elastic isolation layers (120) set on both sides of the existing underground structure (300). The three pile caps (110) include three piles (111) distributed in a triangle and a reinforced concrete cap (112) set on the upper end of the three piles (111). The upper end of the reinforced concrete cap (112) protrudes relative to the existing underground structure (300). The elastic isolation layers (120) are set one-to-one between the reinforced concrete cap (112) and the existing underground structure (300). The newly constructed power tunnel includes a box-shaped tunnel body (200) set on a proximity interference isolation type pile foundation. There is a gap between the box-shaped tunnel body (200) and the existing underground structure (300). The two ends of the box-shaped tunnel body (200) are set on corresponding reinforced concrete abutments (112). The mid-span portion of the box-shaped tunnel body (200) is pre-arched upward relative to the existing underground structure (300). The box-shaped tunnel body (200) includes four rectangular wall panels (210) arranged in sequence. The wall panels (210) are made of shrinkage-compensating concrete with a strength greater than or equal to C40, and the wall panels (210) are provided with prestressed steel strands (211). A steel cable (130) is installed between the reinforced concrete foundations (112) on both sides of the existing underground structure (300). An elastic support block (140) is installed in the middle of the steel cable (130). The elastic support block (140) abuts against the middle of the box-shaped tunnel body (200). The steel cable (130) passes through the elastic isolation layer (120).

2. The cooperative crossing structure for newly constructed power tunnels under proximity interference from existing underground structures as described in claim 1, characterized in that, The elastic isolation layer (120) is configured as a modified rubber-concrete composite isolation layer.

3. The cooperative crossing structure for newly constructed power tunnels under proximity interference from existing underground structures as described in claim 1, characterized in that, The prestressed steel strand (211) is tensioned to 50% of the preset stress during the construction stage of the box-shaped tunnel body (200). After the box-shaped tunnel body (200) and the proximity interference isolation type pile bearing foundation are stabilized under the stress, the prestressed steel strand (211) is tensioned to 100% of the preset stress.

4. The cooperative crossing structure for newly constructed power tunnels under proximity interference from existing underground structures as described in claim 1, characterized in that, The prestressed steel strand (211) is made of steel strand with an outer diameter of 15.2 mm and a standard strength of 1860 MPa.

5. The cooperative crossing structure for newly constructed power tunnels under proximity interference from existing underground structures as described in claim 1, characterized in that, The wall panel (210) is provided with double-layer longitudinal reinforcement (212) that works in conjunction with the prestressed steel strands (211) to bear the force.

6. The cooperative crossing structure for newly constructed power tunnels under proximity interference from existing underground structures as described in claim 1, characterized in that, The expansion agent content of the shrinkage-compensating concrete is 8%~10%.

7. The cooperative crossing structure for newly constructed power tunnels under proximity interference from existing underground structures as described in claim 1, characterized in that, A load transition section (230) is provided between the reinforced concrete foundation (112) and the wall panels (210) on both sides of the box-shaped tunnel body (200).

8. The cooperative crossing structure for newly constructed power tunnels under proximity interference from existing underground structures as described in claim 1, characterized in that, The top sides of the main body (200) of the box-shaped tunnel located within the road area are provided with road load buffer and anti-sinking structures (220).

9. The cooperative crossing structure for newly constructed power tunnels under proximity interference from existing underground structures as described in claim 8, characterized in that, The road load buffer and anti-settlement structure (220) includes a reinforced slab (221), a buffer cushion layer (222), and a wedge-shaped gradient corbel (223). The wedge-shaped gradient corbel (223) is cast on the top of the box-shaped tunnel body (200). The reinforced slab (221) is arranged above the wedge-shaped gradient corbel (223) and protrudes outward. The buffer cushion layer (222) is arranged below the reinforced slab (221) and located outside the wedge-shaped gradient corbel (223).

10. The cooperative crossing structure for newly constructed power tunnels under proximity interference from existing underground structures as described in claim 9, characterized in that, The reinforced slab (221) is a reinforced concrete slab, the buffer cushion layer (222) is a crushed stone cushion layer, and multiple layers of asphalt felt (224) are provided between the reinforced slab (221), the wedge-shaped gradual corbel (223), and the box-shaped tunnel body (200).

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