Reinforcement structure of shield tunnel passing under viaduct foundation and reinforcement method of viaduct foundation

Abstract

The present invention provides a reinforcement structure for a shield tunnel passing under an elevated bridge foundation and a method for reinforcing an elevated bridge foundation. The reinforcement structure comprises: a slurry consolidation body for the shield tunnel to be constructed, comprising a plurality of double-tube rotary jet piles embedded between two adjacent elevated bridge pile foundations, wherein the plurality of double-tube rotary jet piles interlock and consolidate to form the slurry consolidation body; and a retaining pile wall embedded between the elevated bridge pile foundation and the slurry consolidation body, wherein the retaining pile wall has a first side surface and a second side surface facing each other, wherein the first side surface faces the elevated bridge pile foundation and the second side surface faces the slurry consolidation body. The present invention solves the problem that in soft composite strata such as silty clay, tunnels passing under existing elevated bridges at close range can easily endanger the safety of the shield machine and the existing elevated bridge.

Description

Technical Field

[0001] The present invention relates to the technical field of shield tunnel construction, and in particular to a reinforcement structure for a shield tunnel passing under a viaduct foundation and a reinforcement method for the viaduct foundation. Background Art

[0002] Urban rail transit construction often involves tunnels passing under existing viaducts at close range. This is especially true when constructing tunnels in soft composite strata such as silty clay, silt, and mud. The tunnel construction area is a strong impact zone for the viaduct during tunneling by the tunnel boring machine (TBM). These geological strata are extremely compressible, have poor self-stability, and low bearing capacity. The shield machine disturbs the soil during excavation, causing the strata to react sensitively and transmitting pressure rapidly and widely. When the shield machine's cutterhead rotates and cuts, the strata can easily destroy their original relative stability or equilibrium, causing the shield machine to crash and excessive lateral force on the existing viaduct pile foundation, endangering the safety of the shield machine and the existing viaduct. Summary of the Invention

[0003] In order to overcome the defects of the existing technology, a reinforcement structure for a shield tunnel passing under an elevated bridge foundation and a reinforcement method for the elevated bridge foundation are provided to solve the problem that in soft composite strata such as silty clay, the tunnel passing under an existing elevated bridge at close range may endanger the safety of the shield machine and the existing elevated bridge.

[0004] To achieve the above-mentioned purpose, a reinforcement structure for a shield tunnel passing under a viaduct foundation is provided, comprising:

[0005] A slurry consolidation body for the shield tunnel to be constructed comprises a plurality of double-tube jet grouting piles buried between two adjacent elevated bridge pile foundations, wherein the plurality of double-tube jet grouting piles are interlocked and consolidated to form the slurry consolidation body; and

[0006] The retaining pile wall is buried between the viaduct pile foundation and the mud consolidation body. The retaining pile wall has a first side surface and a second side surface facing each other. The first side surface faces the viaduct pile foundation, and the second side surface faces the mud consolidation body.

[0007] Furthermore, the retaining pile wall is arranged along the length direction of the shield tunnel.

[0008] Furthermore, the length of the retaining wall is greater than the outer diameter of the viaduct pile foundation.

[0009] Furthermore, the retaining pile wall includes a plurality of grouting pipe piles connected together, and the plurality of grouting pipe piles are arranged in a row along the length direction of the shield tunnel.

[0010] Furthermore, the grouting pipe pile includes slurry and a grouting pipe. The grouting pipe is provided with a slurry outlet hole. The slurry is poured into the grouting steel pipe. The slurry seeps out of the grouting pipe through the slurry outlet hole and interlocks with the slurry seeping out of the adjacent grouting pipe.

[0011] Furthermore, a plurality of the double-tube jet grouting piles are arranged in a plum blossom shape.

[0012] Furthermore, the mud solidification body is in a prismatic shape.

[0013] The present invention provides a method for reinforcing an elevated bridge foundation, which is characterized by comprising the following steps:

[0014] A retaining pile wall is buried between an elevated bridge pile foundation and a construction site of a shield tunnel to be constructed that passes under two adjacent elevated bridge pile foundations, the retaining pile wall having a first side surface and a second side surface facing each other, such that the first side surface faces the elevated bridge pile foundation and the second side surface faces the construction site;

[0015] A plurality of double-tube jet grouting piles are buried at the construction site, and the double-tube jet grouting piles are interlocked and consolidated to form a mud consolidation body for the shield tunnel to be constructed to pass through.

[0016] Furthermore, the step of burying a retaining pile wall between the pile foundation of the elevated bridge and the construction station of the shield tunnel to be constructed passing under two adjacent pile foundations of the elevated bridge comprises:

[0017] Between the viaduct pile foundation and the construction station, a plurality of grouting pipe piles are buried along the length direction of the shield tunnel, and the plurality of grouting pipe piles are connected together to form the retaining pile wall.

[0018] The beneficial effect of the present invention is that the reinforcement structure of the shield tunnel passing under the elevated bridge foundation of the present invention is achieved by setting a mud consolidation body on the tunnel construction route between the pile foundations of the elevated bridge, and later using a shield machine to excavate the mud consolidation body to form a crossing tunnel in the mud consolidation body, and using the mud consolidation body to resist the stratum pressure, relying on the mud consolidation body to resist the pressure, thereby avoiding the pressure from spreading irregularly to the surroundings under the squeezing of the shield machine, disturbing the elevated bridge pile foundation and thus avoiding the occurrence of danger. On the other hand, if there is stratum disturbance and stratum stress that cannot be completely eliminated by the mud consolidation body, a retaining pile wall is set between the mud consolidation body and the elevated bridge pile foundation to resist the remaining stratum disturbance and stratum stress, avoiding the influence of stratum disturbance and pressure on the elevated bridge pile foundation, thereby ensuring the safety and zero settlement of the elevated bridge. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of a reinforcement structure for a shield tunnel passing under a viaduct foundation according to an embodiment of the present invention.

[0020] Figure 2 This is a front view of a mud consolidation body according to an embodiment of the present invention.

[0021] Figure 3 FIG. 4 is a top view of a mud consolidation body according to an embodiment of the present invention.

[0022] Figures 4 to 6 This is a schematic diagram of the steps of a method for reinforcing a shield tunnel passing under a viaduct foundation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0024] Figure 1 Schematic diagram of the structure of the reinforcement structure of the shield tunnel passing under the viaduct foundation according to the embodiment of the present invention, Figure 2 This is a front view of a mud consolidation body according to an embodiment of the present invention. Figure 3 A top view of a mud consolidation body according to an embodiment of the present invention; Figures 4 to 6 This is a schematic diagram of the steps of a method for reinforcing a shield tunnel passing under a viaduct foundation according to an embodiment of the present invention.

[0025] Reference Figures 1 to 6 As shown, the present invention provides a reinforcement structure for a shield tunnel passing under a viaduct foundation, comprising: a mud consolidation body 1 and a retaining pile wall 2.

[0026] Specifically, the slurry consolidation body 1 comprises a plurality of double-tube jet grouting piles 11. These piles 11 are buried between two adjacent elevated bridge pile foundations 31. These piles 11 interlock and consolidate to form the slurry consolidation body 1. During subsequent shield tunneling, the shield machine 5 excavates the slurry consolidation body 1 along the tunnel's central axis, with the tunnel being constructed passing through the slurry consolidation body.

[0027] The retaining pile wall 2 is embedded between the elevated bridge pile foundation 31 and the slurry consolidation body 1. The retaining pile wall 2 has a first side and a second side facing each other. The first side of the retaining pile wall 2 faces the elevated bridge pile foundation 31, and the second side of the retaining pile wall 2 faces the slurry consolidation body 1.

[0028] The reinforcement structure of the shield tunnel under the elevated bridge foundation of the present invention is achieved by setting a mud consolidation body on the tunnel construction route between the elevated bridge pile foundations, and later using a shield machine to excavate the mud consolidation body to form a through tunnel in the mud consolidation body, using the mud consolidation body to resist the stratum pressure, and relying on the mud consolidation body to resist the pressure (surrounding soil pressure, groundwater bearing pressure, pressure of ground buildings, pressure of ground traffic), thereby avoiding the pressure from spreading irregularly to the surroundings under the squeezing of the shield machine, disturbing the elevated bridge pile foundation and thus avoiding the occurrence of danger. On the other hand, if there is stratum disturbance and stratum stress that cannot be completely eliminated by the mud consolidation body, a retaining pile wall is set between the mud consolidation body and the elevated bridge pile foundation to resist the remaining stratum disturbance and stratum stress, avoiding the influence of stratum disturbance and pressure on the elevated bridge pile foundation, thereby ensuring the safety and zero settlement of the elevated bridge.

[0029] In this embodiment, the mud consolidation body 1 is prismatic and is coaxially arranged with the shield tunnel 4 .

[0030] A plurality of double-tube jet grouting piles 11 are arranged in a plum blossom shape.

[0031] The diameter of the double-tube jet-jet piles 11 is 600 mm, and the pile spacing is 1.1 m × 1.1 m in a plum blossom shape. The reinforcement plane range is 5 m on both sides of the axis of the shield tunnel, and the reinforcement depth is 3 m above the top of the shield tunnel to 4 m below the bottom of the tunnel.

[0032] Double-tube jet grouting piles:

[0033] (1) Grouting should use ordinary Portland cement of grade 42.5 or above, with a water-cement ratio of 0.8:1 to 1.5:1, and the grouting pressure should be no less than 20 MPa;

[0034] (2) Spray nozzle lifting speed: 10cm / min~25cm / min, rotation speed: 10r / min~20r / min;

[0035] (3) Before the construction of double-tube rotary jet grouting piles, test piles shall be carried out to determine the predetermined slurry ratio, injection pressure, injection volume and other technical parameters based on the actual situation. The number of test piles shall not be less than 3.

[0036] (4) After the construction is completed, the pile body should be cored and tested. The unconfined compressive strength should be no less than 0.8 MPa, and the reinforcement effect should be uniform.

[0037] The above-mentioned double-tube rotary jet piles are provided with pressure by compressed air and use cement slurry as the medium. During construction, the rotary jet pile machine is lifted up and down and rotated at the same time. Under the combined action of pressure and medium, a pile with a diameter of 600mm is formed (the diameter of the pile varies according to the machine model). After the construction of one pile is completed, the next rotary jet pile is constructed immediately. The pile spacing is set to 1.1 meters. When the next double-tube rotary jet pile is constructed, it forms an interlocking pile with the previous double-tube rotary jet pile (pile diameter 600mm, spacing 1.1m, interlock 10cm). By analogy, a solid mud consolidation body is formed at the construction station A of the shield tunnel between the pile foundations of adjacent elevated bridges, and the solid mud consolidation body can block the stress disturbance to the stratum caused by the shield machine passing through the mud consolidation body.

[0038] The mud consolidation body in this embodiment is a mixture of cement slurry and surrounding soil, not a complete set of pure cement slurry piles. Its strength is lower than that of cement slurry, but greater than the strength of the surrounding soil itself. Since the strength of the mud consolidation body is lower than that of pure cement, the shield machine's excavation is not affected. However, during the process of the shield machine passing through the mud consolidation body, because the mud consolidation body is stronger than the soil itself, it can block more stratum pressure than the soil itself. At the same time, it assists the retaining pile wall and completely blocks the stratum stress.

[0039] In this embodiment, the role of the mud consolidation body is not only to bear the weight, because the shield machine is dynamic when passing through the mud consolidation body. On the one hand, it is necessary to pass through it safely, and on the other hand, it is necessary to reduce the impact on the surrounding environment. It can both block the formation pressure and pass through it quickly.

[0040] The reinforcement structure of the shield tunnel passing under the viaduct foundation of the present invention has a fast construction speed and low cost, and only requires a small area. It is suitable for construction such as crossing ultra-close viaducts, railway bridges, etc.

[0041] In this embodiment, the retaining pile wall 2 is arranged along the length direction of the shield tunnel 4. The length of the retaining wall is greater than the outer diameter of the viaduct pile foundation 31.

[0042] Specifically, the retaining pile wall 2 includes a plurality of grouting pipe piles connected together. The plurality of grouting pipe piles are arranged in a row along the length direction of the shield tunnel 4.

[0043] The grouting pipe pile includes slurry and a grouting pipe 211. The grouting pipe 211 is provided with a grouting hole. The slurry is poured into the grouting steel pipe. The slurry seeps out of the grouting pipe 211 through the grouting hole and interlocks with the slurry seeping out of the adjacent grouting pipe 211.

[0044] The present invention provides a method for reinforcing an elevated bridge foundation, comprising the following steps:

[0045] S1: A retaining pile wall 2 is buried between the elevated bridge pile foundation 31 and the construction station A of the shield tunnel 4 to be constructed passing under two adjacent elevated bridge pile foundations 31. The retaining pile wall 2 has a first side surface and a second side surface relative to each other, so that the first side surface faces the elevated bridge pile foundation 31 and the second side surface faces the construction station A.

[0046] Specifically, step S1 includes:

[0047] Between the elevated bridge pile foundation 31 and the construction station A, a plurality of grouting pipe piles are buried along the length direction of the shield tunnel 4 , and the plurality of grouting pipe piles are connected together to form a retaining pile wall 2 .

[0048] See Figure 4 As shown, multiple grouting pipes are driven into the soil between the viaduct pile foundation 31 and the construction station A. The multiple grouting pipes are arranged in a row.

[0049] See Figure 5 As shown, cement slurry is injected into the grouting pipe, and the cement slurry seeps out of the grouting pipe through the slurry holes and connects with the cement slurry seeping out of the adjacent grouting pipes to solidify into a retaining pile wall.

[0050] S2: A plurality of double-tube jet grouting piles 11 are buried at the construction site A. The double-tube jet grouting piles 11 are interlocked and consolidated to form a slurry consolidation body for the shield tunnel 4 to be constructed to penetrate.

[0051] Later, during the tunneling process of the shield machine, the shield machine passes through the mud consolidation body. The mud consolidation body and the retaining pile wall jointly resist the pressure and work together to ensure the safety of the elevated bridge pile foundation and ground traffic.

[0052] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for understanding and reading by those familiar with this technology, and are not used to limit the conditions for implementation of the present invention. Therefore, they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0053] The present invention has been described in detail above with reference to the embodiments of the accompanying drawings. A person skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention. The scope of protection of the present invention shall be determined by the scope defined by the appended claims.

Claims

1. A method for reinforcing a reinforced structure of a shield tunnel passing under a viaduct foundation, characterized in that: The reinforcement structure for the shield tunnel passing under the viaduct foundation includes a slurry consolidation body and a retaining pile wall for the shield tunnel to be constructed. The reinforcement method includes the following steps: A retaining pile wall is buried between the elevated bridge pile foundation and the mud consolidation body, wherein the retaining pile wall has a first side surface and a second side surface opposite to each other, such that the first side surface faces the elevated bridge pile foundation and the second side surface faces the mud consolidation body; A plurality of double-tube jet grouting piles are buried at the mud consolidation body, wherein the double-tube jet grouting piles are interlocked and consolidated with each other to form the mud consolidation body; The retaining pile wall is arranged along the length direction of the shield tunnel; The length of the retaining pile wall is greater than the outer diameter of the viaduct pile foundation; The retaining pile wall comprises a plurality of grouting pipe piles connected together, wherein the plurality of grouting pipe piles are arranged in a row along the length direction of the shield tunnel; The grouting pipe pile includes slurry and a grouting pipe. The grouting pipe is provided with a slurry outlet hole. The slurry is poured into the grouting pipe. The slurry seeps out of the grouting pipe through the slurry outlet hole and interlocks with the slurry seeping out of the adjacent grouting pipe.

2. The reinforcement method according to claim 1, characterized in that: A plurality of the double-tube jet grouting piles are arranged in a plum blossom shape.

3. The reinforcement method according to claim 1, characterized in that: The mud consolidation body is in a prismatic shape.

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