Novel shield launching end reinforcing method

Abstract

The invention discloses a novel shield launching end reinforcing method, and relates to the field of large and medium-sized public buildings and the like, in particular to urban rail transit, roads, railways and the like. The method comprises the specific steps that S1, a defense wall body is constructed at the position of a to-be-broken diaphragm wall on the outer side of a capped opening of a station shield tunneling machine placement position; s2, deep hole grouting reinforcement is conducted on the periphery of the defense wall, and a wall back reinforcement body is formed; s3, sealing grouting is conducted at the joint of the defense wall body and the underground diaphragm wall to be broken; and S4, after the wall back reinforcing body is maintained, the underground diaphragm wall to be broken and removed on the outer side of the hole in the position where the shield tunneling machine is placed is broken and removed, and the defense wall is reserved. The gravel sand mixture of the rock filling layer and the sand layer gradually fills the gap between the shield tunneling machine and the soil body along with cutting of the defense wall body by the cutter head in the propelling process of the shield tunneling machine, and dynamic sealing is achieved. The technology is economical, safe, clean, energy-saving, low-carbon and environment-friendly, the scheme is economical and reliable, and the technology is an efficient, energy-saving, environment-friendly and sustainable green shield construction technology.

Description

Technical Field

[0001] This invention relates to fields such as large and medium-sized public buildings, specifically urban rail transit, highways, railways, etc., and particularly to a novel method for reinforcing the starting end of a tunnel boring machine. Background Technology

[0002] Tunnel boring machines (TBMs) are large pieces of equipment used in the construction of tunnels for railways, highways, and subways, and are known in the industry as the "king of construction machinery." They use a cutterhead at the front to break up rock and soil, and then a conveyor system removes the excavated material. Their efficiency far surpasses that of manual labor; a task that would take a thousand workers a year to complete can be finished in a month by a single TBM. Safety is also much higher, as workers do not directly contact hazardous environments, resulting in a near-zero injury or death rate. While existing tunnel boring machine (TBM) construction technology is highly mature in terms of construction safety, operational efficiency, forming quality, adaptability to complex geological conditions, and level of intelligence, there is still room for improvement in some aspects. If the tunnel portal wall cannot be reinforced with fiberglass due to adjustments in the tunnel alignment or material constraints, the initial launch phase will face significant risks and time consumption.

[0003] A novel method for reinforcing the starting end of a tunnel boring machine (TBM) can solve the problems caused by track adjustments and material shortages. This method enables efficient and safe construction during the station retaining structure construction phase, with significant advantages in terms of construction period. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a novel method for reinforcing the starting end of a tunnel boring machine. Includes the following steps: S1: Construct a defensive wall at the location outside the tunnel entrance where the shield tunneling machine is placed, where the diaphragm wall to be demolished is located.

[0005] S2: Deep hole grouting is used to reinforce the outer perimeter of the defensive wall to form a wall back reinforcement.

[0006] S3: Seal and grout at the joint between the defensive wall and the diaphragm wall to be demolished.

[0007] S4: After the wall back is reinforced and cured, the diaphragm wall outside the tunnel entrance where the tunnel boring machine is placed is to be demolished, while the defensive wall is preserved.

[0008] Specifically, the interior of the defensive wall is constructed using fiberglass reinforced steel cages.

[0009] Specifically, the width of the defensive wall is the diameter of the tunnel opening where the tunnel boring machine is placed plus 6 meters, the height is the diameter of the tunnel opening where the tunnel boring machine is placed plus 6 meters, and the thickness is 0.8 to 1.2 meters.

[0010] Specifically, a staged grouting method is adopted, which includes deep hole grouting and sealing grouting. The parameters for deep hole grouting are: grouting diffusion radius ≥ 1.5 meters, grouting pressure 0.3~0.8MPa in the grouting hole; the grouting pressure for sealing grouting is 0.3-0.8MPa in the sealing grouting hole.

[0011] Specifically, the deep hole grouting adopts a quincunx pattern of drilling and skip-hole grouting, and the back wall reinforcement grouting is carried out in sections with a grouting pressure of ≥0.5MPa for each section. The grouting is preferably carried out from bottom to top, and the grouting height of each section does not exceed 3 meters above the shield machine placement location.

[0012] Specifically, after 14 days of curing of the defensive wall, the joint between the diaphragm wall to be demolished and the defensive wall is sealed with grout. Specifically, after the station's retaining structure is broken, the defensive wall, through a composite structure formed by the wall back reinforcement and sealing grouting, independently bears the soil pressure and water pressure.

[0013] Specifically, during the construction of the defensive wall, a hollow pile structure is used in the area 3 meters above the location of the tunnel boring machine, with a stone filling layer and a sand layer set up and backfilled with a mixture of crushed stone and sand.

[0014] Specifically, the crushed stone has a particle size of 5-20mm, the sand is medium to coarse sand, and the mass ratio of crushed stone to sand is 3-2:1.

[0015] Specifically, the mixture of crushed stone and sand in the fill layer and sand layer gradually fills the gap between the tunnel boring machine and the soil as the cutterhead cuts through the defensive wall during the tunnel boring machine's advance, achieving "dynamic sealing".

[0016] This invention provides the following beneficial effects: This invention provides a novel method for reinforcing the starting end of a tunnel boring machine (TBM). This technology is economical, safe, clean, energy-saving, low-carbon, and environmentally friendly. The solution is economical and reliable, and it is a green TBM construction technology that is efficient, energy-saving, environmentally friendly, and sustainable.

[0017] This invention provides a novel method for reinforcing the starting end of a tunnel boring machine. The technology has been demonstrated through extensive scientific research and has significant advantages such as feasibility, operability, short construction period, low construction cost, minimal environmental impact, and good safety performance in tunnel spatial locations under force majeure conditions. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, 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 the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the novel shield tunneling starting end reinforcement structure in this invention; Figure 2 This is a construction schematic diagram of the novel shield tunneling starting end reinforcement method of the present invention; Attached reference numerals: 1-Diaphragm wall of station, 2-Site side wall of station, 3-Diaphragm wall to be demolished, 4-Defense wall, 5-Wall back reinforcement, 6-Grouting hole, 7-Sealed grouting hole, 8-Shield machine placement location, 9-Shield tunnel outline, 10-Plain soil layer, 11-Rock fill layer, 12-Sand layer. Detailed Implementation

[0020] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0021] The following detailed description of the implementation method of the present invention is in conjunction with the accompanying drawings. The description is only a partial embodiment and not all embodiments. For clarity, representations and descriptions unrelated to the present invention are omitted in the drawings and description.

[0022] To provide a clearer understanding of the technical features, objectives, and beneficial effects of this invention, the following detailed description of the technical solution is provided. Obviously, the described embodiments are only a portion of the embodiments of this invention, not all of them, and should not be construed as limiting the scope of implementation of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention.

[0023] Example 1 This embodiment provides a novel method for reinforcing the starting end of a tunnel boring machine (TBM): it mainly involves a series of operations performed at the tunnel portal outside the already capped diaphragm wall 1 of the station. In this embodiment, the width of the defensive wall 4 to be constructed is first measured, and the thickness is determined according to the actual situation. Then, the construction is carried out in sections close to the diaphragm wall 3 to be demolished. The steel cage inside the defensive wall 4 is made of glass fiber reinforcement. After it is lowered into place, it is poured. No concrete is poured above 3 meters of the opening, which is an empty pile part. The mixture of gravel and sand is backfilled to ensure that the sealing is guaranteed after the start. In this embodiment, the construction of the wall back reinforcement 5 begins 14 days after the completion of the defensive wall 4. The reinforcement construction first involves drilling grouting holes 7 at the joints and grouting. After completion, the reinforcement behind the wall is reinforced by drilling and grouting. The holes are arranged in a quincunx pattern and grouting is done in a skip-hole manner to ensure that the grout can spread to all the gaps.

[0024] In this embodiment, the diaphragm wall to be demolished is carried out 28 days after the grouting of the wall back reinforcement 5. After demolition, preparations are made for the launch of the tunnel boring machine 8. During the launch preparation period, the safety of the station is ensured by the defensive wall 4 and the wall back reinforcement 5. The tunnel can be started immediately after the preparation work is completed, without any interruption time.

[0025] Example 2 In this embodiment, after the construction of the station enclosure structure is completed and the foundation pit is closed, earthwork excavation begins, and after excavation to the foundation, the main structure is constructed. In this embodiment, a circular tunnel portal for shield tunneling is reserved on the end wall during the construction of the main structure of the station. After the main structure is completed, a defensive wall 4 is constructed within the area of ​​the shield tunnel portal. The thickness of the defensive wall 4 is 0.8~1.2m, the width is the diameter of the tunnel portal plus 6m, that is, it covers 3m on the left and right sides. The height of the defensive wall 4 is the diameter of the tunnel portal, that is, it covers 3m on the top and bottom sides. In this embodiment, after the defensive wall 4 is constructed, the wall back reinforcement 5 is grouted. Grouting is carried out first at the joint between the retaining wall and the defensive wall 4. After the joint is reinforced, the wall back reinforcement 5 is reinforced. The reinforcement is reinforced by drilling holes in a quincunx pattern. Grouting is done by skipping holes. Grouting should preferably be done in sections from bottom to top. The pipe can only be lifted after the grouting pressure or grouting volume of the previous section reaches the required level. The grouting of the hole can be stopped 3 meters above the entrance. This step is repeated to reinforce the remaining holes.

[0026] In this embodiment, the enclosure wall can be broken down after 28 days of reinforcement, while the defensive wall 4 is preserved. The vibration generated during the breaking down will affect the defensive wall 4, but the reinforced body behind the wall will provide protection, so there will be no safety risk.

[0027] Example 3 In this embodiment, if a sudden shortage of materials or adjustments to the entire route during construction causes the rear portal space to be adjusted upwards, this reinforcement scheme can be used to compensate for this in order to ensure the smooth passage of the tunnel boring machine and maintain control over the construction period and safety. This method is significantly cheaper and greatly improves safety. This method can guarantee construction quality and ensure delivery according to the owner's predetermined schedule, and even deliver ahead of schedule, thus obtaining an early completion bonus.

[0028] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A novel method for reinforcing the starting end of a tunnel boring machine, characterized in that, Includes the following steps: S1: Construct a defensive wall (4) at the location of the shield tunneling machine (8) outside the tunnel opening of the station that has been capped and is to be demolished, at the diaphragm wall (3). S2: Deep hole grouting is carried out to reinforce the perimeter of the defensive wall (4) to form a wall back reinforcement body (5); S3: Seal and grout at the joint between the defensive wall (4) and the diaphragm wall (3) to be demolished; S4: After the wall back reinforcement (5) is cured, the diaphragm wall (3) outside the tunnel opening (8) where the tunnel boring machine is placed is broken, and the defensive wall (4) is retained.

2. The shield tunneling starting end reinforcement method according to claim 1, characterized in that: The interior of the defensive wall (4) is made of glass fiber reinforced steel cage.

3. The shield tunneling starting end reinforcement method according to claim 1, characterized in that: The width of the defensive wall (4) is the diameter of the tunnel boring machine placement (8) plus 6 meters, the height is the diameter of the tunnel boring machine placement (8) plus 6 meters, and the thickness is 0.8~1.2 meters.

4. The shield tunneling starting end reinforcement method according to claim 1, characterized in that: The grouting is carried out in stages, which includes deep hole grouting and sealing grouting. The parameters of deep hole grouting are: grouting diffusion radius ≥ 1.5 meters, grouting pressure 0.3-0.8 MPa in grouting hole (6); the grouting pressure of sealing grouting is 0.3-0.8 MPa in sealing grouting hole (7).

5. The shield tunneling starting end reinforcement method according to claim 3, characterized in that: The deep hole grouting adopts a plum blossom pattern of drilling and skip-hole grouting. The wall back reinforcement (5) is grouted in sections, with a grouting pressure of ≥0.5MPa for each section. The grouting is carried out from bottom to top, and the grouting height of each section does not exceed 3 meters above the opening of the shield machine placement (8). After the defensive wall (4) has been cured for 14 days, the joint between the diaphragm wall (3) to be broken and the defensive wall (4) is sealed with grout.

6. The shield tunneling starting end reinforcement method according to claim 1, characterized in that: After the station enclosure structure is broken, the defensive wall (4) independently bears the soil pressure and water pressure through the composite structure formed by the wall back reinforcement (5) and sealing grouting.

7. The shield tunneling starting end reinforcement method according to claim 1, characterized in that: During the construction of the defensive wall (4), a hollow pile structure is adopted in the area 3 meters above the shield machine placement area (8), with a stone filling layer (11) and a sand layer (12) set up and backfilled with a mixture of crushed stone and sand.

8. The shield tunneling starting end reinforcement method according to claim 7, characterized in that: The crushed stone has a particle size of 5-20mm, the sand is medium to coarse sand, and the mass ratio of crushed stone to sand is 3-2:

1.

9. The shield tunneling starting end reinforcement method according to claim 7, characterized in that: During the tunnel boring machine's advance, the mixture of crushed stone and sand in the fill layer (11) and sand layer (12) gradually fills the gap between the tunnel boring machine and the soil as the cutterhead cuts the defensive wall (4), thus achieving "dynamic sealing".

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