Newly-built small-distance overpassing existing tunnel with bench beam structure

Abstract

The utility model provides a kind of bench beam structure of new tunneling tunnel small distance overcrossing existing tunnel, belong to tunnel and underground engineering construction technical field, including multiple pile body and top pipe beam;Multiple pile body is placed in existing tunnel two sides respectively, is vertically set, and pile end is embedded in stratum;Top pipe beam is fixedly connected in the pile top of multiple pile body, is horizontally set, and two ends are located in existing tunnel two sides respectively;Multiple pile body and top pipe beam combination form bench beam structure and ride on in existing tunnel above, form the compression top structure to existing tunnel, and bench beam structure is located below new tunneling tunnel.The utility model provides a kind of bench beam structure of new tunneling tunnel small distance overcrossing existing tunnel, by the bench beam structure of multiple pile body and top pipe beam composition separates upper and lower tunnel, bears the influence produced by new tunnel excavation unloading, effectively resists the rebound deformation of existing tunnel caused by new tunnel excavation.

Description

Technical Field

[0001] This utility model belongs to the field of tunnel and underground engineering construction technology, and more specifically, it relates to a bench beam structure for a newly built mined tunnel to cross an existing tunnel with a small clearance. Background Technology

[0002] To fully utilize space and avoid urban congestion, the rapid development of urban rail transit has led to increasingly complex transportation networks. New lines inevitably intersect or closely intersect with existing lines. When constructing a tunnel that crosses an existing tunnel, the unloading during excavation can easily cause the underlying tunnel to deform upwards. The excavation of subway tunnels disrupts the original equilibrium of the strata, leading to stress redistribution and causing deformation and displacement of nearby existing tunnel structures. Ensuring the safety of new subway tunnel construction while minimizing the impact on existing tunnels is a crucial engineering problem that must be solved. When a new tunnel, especially a large-section tunnel with a small clearance, crosses an existing tunnel, the disturbance to the existing tunnel is even greater, potentially posing a greater threat to its normal operation and safe use, and increasing the construction difficulty. Due to the very small clearance between the upper and lower tunnels, commonly used ground grouting reinforcement measures are insufficient to control the deformation of the existing tunnel within acceptable limits. Therefore, a structure needs to be constructed between the new tunnel and the existing tunnel to transfer the load and ensure the structural safety of the existing tunnel. Utility Model Content

[0003] The purpose of this utility model is to provide a bench beam structure for a newly constructed underground tunnel with a small clearance spanning an existing tunnel, aiming to solve the technical problem of safety hazards caused by the upward deformation of the existing tunnel due to the excavation of the underground tunnel.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is: to provide a bench beam structure for a newly constructed mined tunnel with a small clearance spanning an existing tunnel, comprising:

[0005] Multiple piles are placed on both sides of the existing tunnel, arranged vertically, with the pile ends embedded in the stratum.

[0006] A pipe jacking beam is fixedly connected to the top of multiple piles, and the pipe jacking beam is horizontally arranged with its two ends located on both sides of the existing tunnel.

[0007] Among them, multiple piles and the jacking beam are combined to form a bench beam structure that straddles the existing tunnel, forming a capping structure for the existing tunnel. The bench beam structure is located below the newly built mined tunnel.

[0008] In one possible implementation, at least one pile is provided on each side of the existing tunnel, and the jacking beam and the piles connected to it are combined to form a set of bench beam structures, with multiple sets of bench beam structures provided across the existing tunnel.

[0009] In one possible implementation, the newly constructed tunnel is constructed using the CRD method. One of the aforementioned pipe jacking beams is arranged directly below the left and right lower guide tunnels of the newly constructed tunnel. Multiple piles are respectively connected to the two pipe jacking beams, and the axial direction of the pipe jacking beams is parallel to the length direction of the newly constructed tunnel.

[0010] In one possible implementation, the portion of the jacking beam that intersects with the pile body needs to be cut into holes.

[0011] In one possible implementation, the pile body includes a reinforcing cage and a first concrete pour, and the jacking beam includes a hollow jacking pipe and beam stirrups set inside the jacking pipe, an I-beam connected to the beam stirrups, a threaded steel bar laid on the upper part of the I-beam, and a second concrete pour inside the jacking pipe.

[0012] In one possible implementation, the reinforcing cage is a structure formed by combining multiple main bars, multiple spiral stirrups, and multiple reinforcing stirrups; the multiple main bars are arranged vertically and combined to form a circle; the spiral stirrups wrap around the outside of the multiple main bars to form a spiral shape and are connected to the multiple main bars; the reinforcing stirrups are arranged inside the multiple main bars and are connected to the multiple main bars, and the upper ends of the main bars extend into the jacking pipe.

[0013] In one possible implementation, the I-beam is welded to the upper main reinforcement of the steel cage to fix the jacking beam and the pile body.

[0014] In one possible implementation, the length direction of the I-beam is parallel to the axial direction of the jacking beam, and the I-beams are multiple and arranged in parallel with equal spacing, with the I-beams located in the lower middle part of the jacking beam.

[0015] In one possible implementation, the outer wall of the pile body is provided with a protective wall structure.

[0016] In one possible implementation, the diameter of the pile is smaller than the diameter of the jacking beam.

[0017] The beneficial effects of the bench beam structure for a newly constructed underground tunnel with a small clearance span over an existing tunnel provided by this utility model are as follows: Compared with the prior art, the bench beam structure for a newly constructed underground tunnel with a small clearance span over an existing tunnel includes multiple piles and a jacking beam. The multiple piles are respectively placed on both sides of the existing tunnel, arranged vertically, with the pile ends embedded in the stratum. The jacking beam is fixedly connected to the pile tops of the multiple piles, arranged horizontally, with both ends located on both sides of the existing tunnel. The multiple piles and the jacking beam combine to form a bench beam structure that straddles the existing tunnel, forming a capping structure for the existing tunnel. The bench beam structure is located below the newly constructed underground tunnel, solving the technical problem of safety hazards caused by the upward deformation of the existing tunnel due to the excavation of the underground tunnel when the newly constructed underground tunnel spans over an existing tunnel with a small clearance span. The bench beam structure formed by the jacking beam and the piles separates the upper and lower tunnels, bears the impact of unloading during the excavation of the new tunnel, and effectively resists the rebound deformation of the existing tunnel caused by the excavation of the new tunnel. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A three-dimensional schematic diagram showing the positional relationship between the bench beam structure of a newly constructed mined tunnel with a small clearance over an existing tunnel and the two types of tunnels, provided for an embodiment of this utility model.

[0020] Figure 2 A schematic diagram of a bench beam structure for a newly constructed mined tunnel with a small clearance spanning an existing tunnel, provided as an embodiment of this utility model;

[0021] Figure 3 A side view of the relative position of the bench beam structure and the tunnel in a newly constructed mined tunnel with a small clearance over an existing tunnel, provided as an embodiment of this utility model.

[0022] Figure 4 A schematic diagram showing the positional relationship between the jacking pipe and bored piles of the bench beam structure that crosses an existing tunnel with a small clearance in a newly constructed underground tunnel, and the cross-section of the newly constructed underground tunnel, provided for an embodiment of this utility model.

[0023] Figure 5 Internal structural diagram of the bench beam structure for a newly constructed mined tunnel with a small clearance over an existing tunnel, provided for an embodiment of this utility model;

[0024] Figure 6The internal cross-sectional view of the jacking beam of the bench beam structure of the newly built mined tunnel with a small clearance over an existing tunnel provided for the embodiment of this utility model (222 in the figure represents the area of ​​cast-in-place concrete);

[0025] Figure 7 A top view of the steel cage structure of the bench beam structure for a newly constructed mined tunnel with a small clearance spanning an existing tunnel, provided as an embodiment of this utility model.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1. Pile body; 11. Reinforcing cage; 111. Main reinforcement; 112. Spiral stirrups; 113. Reinforcing stirrups; 12. First concrete; 13. Retaining wall structure; 2. Pipe jacking beam; 21. I-beam; 22. Second concrete; 221. Plain concrete cushion layer; 222. Cast-in-place concrete; 23. Pipe jacking; 24. Beam stirrups; 25. Threaded steel; 3. Existing tunnel; 4. Newly constructed mined tunnel; 41. Left upper pilot tunnel; 42. Left lower pilot tunnel; 43. Right upper pilot tunnel; 44. Right lower pilot tunnel. Detailed Implementation

[0028] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0029] Please refer to the following: Figures 1 to 7 The present invention describes a bench beam structure for a newly constructed underground tunnel with a small clearance spanning an existing tunnel. The bench beam structure comprises multiple piles 1 and a jacking beam 2. The piles 1 are respectively placed on both sides of the existing tunnel 3, arranged vertically, with their ends embedded in the ground. The jacking beam 2 is fixedly connected to the tops of the piles 1, arranged horizontally, with both ends located on both sides of the existing tunnel 3. The piles 1 and the jacking beam 2 combine to form a bench beam structure that straddles the existing tunnel 3, forming a capping structure for the existing tunnel 3. The bench beam structure is located below the newly constructed underground tunnel 4.

[0030] The bench beam structure for a newly constructed underground tunnel with a small clearance spanning an existing tunnel provided by this utility model, compared with the prior art, uses multiple piles 1 combined with a jacking beam 2 to form a bench beam that straddles the existing tunnel 3, enabling load transfer and ensuring the structural safety of the existing tunnel 3. It solves the technical problem of safety hazards caused by the upward deformation of the existing tunnel 3 due to the excavation of the newly constructed underground tunnel 4 spanning the existing tunnel 3 with a small clearance. The bench beam structure formed by the jacking beam 2 and the piles 1 separates the upper and lower tunnels (referring to the existing tunnel 3 and the newly constructed underground tunnel 4), bears the impact of unloading during the excavation of the newly constructed underground tunnel 4, and effectively resists the rebound deformation of the existing tunnel 3 caused by the excavation of the newly constructed underground tunnel 4.

[0031] In this utility model Figure 1 and Figure 2 The text indicates that each jacking beam 2 is connected to three piles 1, meaning that the existing tunnel is a two-way tunnel, consisting of two tunnels set up in parallel.

[0032] In this invention, "small clearance" refers to a tunnel layout where the soil thickness between adjacent tunnels is less than a certain value. With the development of highway, railway, and urban rail transit construction, route selection is often constrained by conditions, resulting in minimum clearances between adjacent tunnels at intersections that are less than a certain value, adversely affecting the structural safety of existing tunnels. Therefore, measures such as the bench beam structure of this invention are necessary to reduce the impact of new tunnel construction on existing tunnels.

[0033] In this embodiment, if there is only one existing tunnel 3, then one pile 1 is installed on each side of the existing tunnel 3, and the jacking beam 2 spans across the existing tunnel 3 and is connected to the pile 1. If there are two existing tunnels 3 arranged side by side (bidirectional tunnels), then at least three piles 1 are installed side by side, with the middle pile 1 located between the two existing tunnels 3, such as... Figure 1 and Figure 3 As shown. The jacking beam 2 is a horizontal cylindrical shape, fixedly connected to the upper ends of three piles 1, forming a structure similar to a "bench", hence the name "bench beam". Since this bench beam is placed on top of the existing tunnel 3, it is called a "coping" structure, i.e., a bench beam coping structure. The diameter of the jacking beam 2 is larger than the outer diameter of the piles 1.

[0034] In some embodiments, please refer to Figures 1 to 7At least one pile 1 is installed on each side of the existing tunnel 3. The pipe jacking beam 2 and the pile 1 connected to it form a set of bench beam structures. Multiple sets of bench beam structures are installed across the existing tunnel 3. The pile ends of the pile 1 are stably embedded in the stratum. To minimize the upward deformation of the existing tunnel 3, multiple sets of bench beam structures are installed across the length of the existing tunnel 3. They can be installed at equal intervals or close to each other, depending on the actual conditions of the stratum. This ensures the safe construction of the new mined tunnel 4 and the normal operation of the existing tunnel 3.

[0035] In some embodiments, please refer to Figures 1 to 7 The newly constructed underground tunnel 4 was constructed using the CRD method. Internally, the tunnel is divided into a left upper pilot tunnel 41, a left lower pilot tunnel 42, a right upper pilot tunnel 43, and a right lower pilot tunnel 44. Figure 4 The four areas divided by the newly constructed mined tunnel 4 are correspondingly arranged. This construction method can refer to existing technologies and will not be elaborated here. A pipe jacking beam 2 is arranged directly below the left lower guide tunnel 42 and the right lower guide tunnel 44 of the newly constructed mined tunnel 4. Multiple piles 1 are respectively connected to two pipe jacking beams 2, and the axial direction of the pipe jacking beams 2 is parallel to the length direction of the newly constructed mined tunnel 4. In this embodiment, this arrangement of the pipe jacking beams 2 can maximize the structural safety of the existing tunnel 3, and the effect is good. Figure 4 The dashed line in the diagram indicates the location of pile 1.

[0036] In some embodiments, please refer to Figures 1 to 7 The portion of the jacking beam 2 that intersects with pile 1 needs to be cut into holes, i.e. Figure 2 , Figure 3 and Figure 5 The lower and upper ends of the pipe jacking beam 2, which are in contact with the pile body 1, are cut with holes. During construction, the pile body 1 can pass through the holes, and the pile body 1 and the pipe jacking beam 2 are fixedly connected. Figure 5 Two holes are cut at the positions where the upper and lower ends of the jacking beam 2 intersect with the pile body 1.

[0037] In some embodiments, please refer to Figures 1 to 7 The pile body 1 includes a reinforcing cage 11 and a first concrete 12. The jacking beam 2 includes a hollow jacking pipe 23, beam stirrups 24 installed inside the jacking pipe 23, I-beams 21 connected to the beam stirrups 24, threaded steel bars 25 laid on top of the I-beams 21, and a second concrete 22 poured inside the jacking pipe 23. The use of I-beams 21 and threaded steel bars 25 enhances the structural rigidity of the jacking beam. After the first concrete 12 solidifies, it bonds with the reinforcing cage 11 to form a whole, namely the pile body 1. After the second concrete 22 solidifies, it combines with the jacking pipe 23, beam stirrups 24, I-beams 21, and threaded steel bars 25 to form a whole, namely the jacking beam 2.

[0038] Specifically, the second concrete 22 includes a plain concrete cushion layer 221 and a cast-in-place concrete 222. The plain concrete cushion layer 221 is located below the I-beam 21, forming a support for the I-beam 21, and is constructed first. The cast-in-place concrete 222 is located above the plain concrete cushion layer 221, and is cast after the I-beam 21, threaded steel 25, etc. are laid, so that the inside of the jacking pipe 23 is filled, and is constructed later.

[0039] In some embodiments, please refer to Figures 1 to 7 The reinforcing cage 11 is a structure formed by combining multiple main reinforcing bars 111, multiple spiral stirrups 112, and multiple reinforcing stirrups 113. The main reinforcing bars 111 are arranged vertically and combined to form a circle. The spiral stirrups 112 wrap around the outside of the circular main reinforcing bars 111, forming a spiral shape, and are welded or tied to the main reinforcing bars 111. The reinforcing stirrups 113 are arranged inside the main reinforcing bars 111 and are welded or tied to them. The upper ends of the main reinforcing bars 111 extend into the holes of the jacking beam 2 and are placed inside the jacking pipe 23. The pile body 1 serves as an anti-tension pile. During welding, the concrete at the upper end of the pile body 1 is broken to expose the main reinforcing bars 111 extending from the upper end of the reinforcing cage 11. The main reinforcing bars 111 are then bent, anchored into the jacking beam 2, and then welded to the I-beam 21.

[0040] To achieve a fixed connection between the pipe jacking beam 2 and the pile 1, in some embodiments, please refer to... Figures 1 to 6 The I-beam 21 is welded to the upper end of the reinforcing cage 11 to fix the jacking beam 2 and the pile 1. The welding connection can permanently fix the jacking beam 2 and the pile 1 into a whole, which can improve the overall structural stability.

[0041] In some embodiments, please refer to Figures 1 to 7 The length direction of the I-beam 21 is parallel to the axial direction of the jacking beam 2. There are multiple I-beams 21 arranged in parallel and at equal intervals. The I-beams 21 are located in the lower middle part of the inner side of the jacking beam 2.

[0042] In some embodiments, please refer to Figures 1 to 5 The outer wall of the pile body 1 is provided with a protective wall structure 13.

[0043] The retaining wall structure 13 is used when manually excavated bored piles are subjected to earth pressure, which can lead to soil collapse. To ensure the safety and quality of bored pile construction, retaining wall measures are usually required, especially in complex geological conditions. Different types of retaining wall structures 13 should be used for different soil conditions, taking into account structural strength and economic costs. Commonly used retaining wall structures include: brick retaining walls, cast-in-place concrete retaining walls, steel sleeve retaining walls, shotcrete quick-setting concrete retaining walls, and corrugated steel formwork retaining walls. In special cases, retaining walls are also used for the enlarged head portion of the pile end, such as combined steel plate concrete retaining walls. Each type of retaining wall has its advantages, disadvantages, and applicable scope. The appropriate retaining wall structure should be selected based on the specific engineering geological and hydrogeological conditions of the site, ensuring the safety of construction personnel, and comprehensively considering factors such as construction period and economy.

[0044] In some embodiments, please refer to Figures 1 to 5 Pile 1 is a manually excavated bored pile. Manually excavated bored piles are reinforced concrete piles that are manually excavated and cast on-site. Their installation method or construction method can be found in existing technology. For example... Figure 5 As shown, the portion of the manually excavated bored pile above the jacking beam 2 is an empty pile, and the first concrete 11 is not poured. During the excavation of the newly constructed cut-and-cover tunnel 4, the excess artificial retaining wall is removed. The first concrete 11 is poured from bottom to top up to the height of the plain concrete cushion layer 221, and then pouring is stopped, exposing the main reinforcement 111. If the main reinforcement 111 is not exposed, it can be exposed by manual chiseling. Only after it is exposed can it be welded to the I-beam 21.

[0045] The diameter, length, and quantity of the jacking beam 2 and manually excavated piles under the newly constructed underground tunnel 4 are set according to the actual project needs; the diameter of the manually excavated piles (pile body 1) is slightly smaller than the diameter of the jacking beam 2, and the net distance between the manually excavated piles and the existing tunnel 3 should not be too small, so as to prevent adverse effects on the existing tunnel 3 when the excavated piles are constructed.

[0046] This utility model proposes a micro-deformation control measure for a newly constructed underground tunnel 4 that crosses an existing tunnel 3 with a small clearance, which has at least the following advantages and effects:

[0047] 1) During the construction process of this utility model, the manually excavated bored piles can be constructed in the underground tunnel without being affected by external conditions; the construction of the pipe jacking beam 2 is carried out in the working shaft, which has little impact on ground traffic.

[0048] 2) This utility model separates the upper and lower tunnels through the bench beam structure formed by the jacking beam 2 and the pile body 1, and bears the impact of unloading during the excavation of the new underground tunnel 4. It can effectively resist the rebound deformation of the existing tunnel 3 caused by the excavation of the new underground tunnel 4.

[0049] 3) The bench beam structure straddles the existing tunnel 3 as its permanent protective structure, which can reduce the adverse effects of the dynamic load of the subway operation on the existing tunnel 3 structure in the later stage.

[0050] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A bench beam structure for newly-built under excavation tunnel small clear distance overpass existing tunnel, characterized in that, include: Multiple piles are placed on both sides of the existing tunnel, arranged vertically, with the pile ends embedded in the stratum. A pipe jacking beam is fixedly connected to the top of multiple piles, and the pipe jacking beam is horizontally arranged with its two ends located on both sides of the existing tunnel. Among them, multiple piles and the jacking beam are combined to form a bench beam structure and straddle the existing tunnel, forming a capping structure for the existing tunnel. The bench beam structure is located below the newly built mined tunnel. The pile body includes a reinforcing cage and a first concrete pour. The jacking beam includes a hollow jacking pipe, beam stirrups set inside the jacking pipe, I-beams connected to the beam stirrups, threaded steel laid on the upper part of the I-beams, and a second concrete pour inside the jacking pipe.

2. The bench beam structure for a newly constructed mined tunnel with a small clearance spanning an existing tunnel as described in claim 1, characterized in that, At least one pile is installed on each side of the existing tunnel. The jacking beam and the pile connected to it are combined to form a set of bench beam structures. Multiple sets of bench beam structures are installed across the existing tunnel.

3. The bench beam structure for a newly constructed mined tunnel with a small clearance spanning an existing tunnel as described in claim 1, characterized in that, The newly constructed tunnel is constructed using the CRD method. One of the aforementioned pipe jacking beams is arranged directly below the left and right lower pilot tunnels of the newly constructed tunnel. Multiple piles are respectively connected to the two pipe jacking beams. The axial direction of the pipe jacking beams is parallel to the length direction of the newly constructed tunnel.

4. The bench beam structure for a newly constructed mined tunnel with a small clearance spanning an existing tunnel as described in claim 1, characterized in that, The portion of the jacking beam that intersects with the pile body needs to be cut into holes.

5. The bench beam structure for a newly constructed mined tunnel with a small clearance spanning an existing tunnel as described in claim 1, characterized in that, The steel cage is a structure formed by combining multiple main bars, multiple spiral stirrups, and multiple reinforcing stirrups. The multiple main bars are arranged vertically and combined to form a circle. The spiral stirrups wrap around the outside of the multiple main bars to form a spiral shape and are connected to the multiple main bars. The reinforcing stirrups are arranged inside the multiple main bars and are connected to the multiple main bars. The upper ends of the main bars extend into the jacking pipe.

6. The bench beam structure for a newly constructed mined tunnel with a small clearance spanning an existing tunnel as described in claim 1, characterized in that, The I-beam is welded to the upper main reinforcement of the steel cage to fix the jacking beam and the pile.

7. The bench beam structure for a newly constructed mined tunnel with a small clearance spanning an existing tunnel as described in claim 1, characterized in that, The length direction of the I-beam is parallel to the axial direction of the jacking beam. There are multiple I-beams arranged in parallel and at equal intervals. The I-beams are located in the lower middle part of the jacking beam.

8. The bench beam structure for a newly constructed mined tunnel with a small clearance spanning an existing tunnel as described in claim 1, characterized in that, The outer wall of the pile is provided with a protective wall structure.

9. The bench beam structure for a newly constructed mined tunnel with a small clearance spanning an existing tunnel as described in claim 1, characterized in that, The diameter of the pile is smaller than the diameter of the jacking beam.

Images