Shield receiving method

Abstract

The invention discloses a shield receiving method which comprises the following steps: constructing a subsurface tunnel which is arranged in an aligned manner along the advancing direction of a shield tunnel; constructing a front blocking wall at the front part of the subsurface tunnel; a rear blocking structure is constructed on the rear portion of the subsurface tunnel, so that a cavity is formed between the front blocking wall and the rear blocking structure; and filling a filling material into the cavity for receiving the shield tunneling machine. According to the shield receiving method provided by the invention, a closed filling area can be created, and pressure balance is realized after the shield tunneling machine tunnels to the area, so that safe and reliable shield receiving is ensured.

Description

Technical Field

[0001] This application relates to the field of tunnel construction, and more specifically, to a method for receiving a tunnel boring machine (TBM) during tunnel construction. Background Technology

[0002] With the development of tunnel construction technology, the shield tunneling method has gradually become the mainstream method for tunnel construction. Typically, the shield receiving process involves: before the shield machine approaches the receiving shaft, grouting is performed to reinforce the strata at the end, and a portal sealing device is installed on the end wall of the receiving shaft. After the shield enters the receiving base, the curtain fabric is pressed tightly onto the shield by pressure plates to form a seal, and grease or mortar is injected into the sealed cavity through grouting holes to seal the gaps. Corresponding solutions for shield receiving have been proposed in the industry. For example, Chinese invention patent publication CN111396066 A (Chinese patent application number 202010235336.1, entitled "RATB Combined Shield Receiving Construction Method") discloses a shield receiving construction method, such as... Figure 1 As shown, this method involves arranging sleeve valve pipes along both sides of the tunnel in the corresponding underground excavation section on the surface to grout the surface subsidence area and the shield receiving section; horizontal advanced curtain grouting inside the tunnel; setting up dewatering wells and well pipe dewatering; underground excavation at the receiving end; setting up a sealing wall; and backfilling with counterpressure after the sealing wall is completed.

[0003] This receiving method relies heavily on the quality of precipitation and foundation reinforcement. Insufficient reinforcement quality or coverage can lead to water and soil pressure imbalance, easily causing safety issues such as ground subsidence. Furthermore, after the shield enters the ground, emergency wall construction and counter-pressure backfilling are required. If there are localized weak points in the initial ground reinforcement or if the precipitation effect does not fully cover the area, safety hazards such as surface subsidence due to water and soil pressure imbalance will still exist during this period, making it impossible to reliably and stably receive the tunnel boring machine. In addition, the costs of precipitation and foundation reinforcement construction are also very high.

[0004] Therefore, how to propose a simple and reliable solution for receiving tunnel boring machines has become a technical problem that needs to be solved in this field. Summary of the Invention

[0005] In view of this, this application proposes a shield tunneling machine receiving method, which includes: The construction involves excavating a cut-and-cover tunnel aligned with the direction of travel of the shield tunnel; constructing a front sealing wall at the front of the cut-and-cover tunnel; constructing a rear sealing structure at the rear of the cut-and-cover tunnel, thereby forming a cavity between the front sealing wall and the rear sealing structure; and filling the cavity with filling material to receive the shield machine.

[0006] Preferably, the filling material completely fills the cavity.

[0007] Preferably, the filling material includes one or more of cohesive soil, lime-soil, graded sand and gravel, low-grade plain concrete, and foamed concrete, and the density of the filling material in the cavity reaches a medium-density state or above after filling is completed.

[0008] Preferably, the filling material includes a controllable low-strength material, such as fluidized bed soil, low-grade plain concrete, industrial solid waste-based solidified soil, biopolymer solidified soil, clinker-free cementitious material-based solidified soil, red mud-based solidified soil, engineering slag-based solidified soil, and lightweight foamed soil.

[0009] Preferably, the material of the front sealing wall is a machinable material that allows the tunnel boring machine to cut it.

[0010] Preferably, the front sealing wall comprises a wall made of C25 shotcrete and a fiberglass reinforced steel frame embedded in the wall.

[0011] Preferably, the construction tunnel includes a construction tunnel support structure, the inner diameter of which is greater than or equal to the outer diameter of the cutterhead of the tunnel boring machine.

[0012] Preferably, the support structure for the mined tunnel includes a support reinforcement section with a reduced inner diameter, which is arranged adjacent to the front sealing wall, and the inner diameter of the support reinforcement section is greater than or equal to the outer diameter of the cutterhead of the tunnel boring machine.

[0013] Preferably, the post-sealing structure includes a post-sealing wall.

[0014] Preferably, the shield receiving method includes: the rear sealing wall is integrally cast and formed, and a grouting pipe is pre-embedded in the lower part of the rear sealing wall, and an exhaust hole is provided in the upper part of the rear sealing wall, and a controllable low-strength material is filled from bottom to top through the grouting pipe to saturate the cavity.

[0015] Preferably, the post-sealing structure includes a sealing wall support, which is located on the free side of the sealing wall and supports the post-sealing wall.

[0016] Preferably, the net distance between the rear sealing structure and the front sealing wall is greater than the length of the tunnel boring machine head.

[0017] The shield receiving method proposed in this application can create a closed filling zone, achieving pressure balance after the shield machine tunnels into this area, thereby ensuring safe and reliable shield receiving. When the filling zone is saturated, it forms an impermeable barrier, blocking external groundwater seepage channels and providing an impermeable construction environment for the shield receiving process. This avoids safety accidents such as foundation collapse caused by water and sand inrush, improves the safety of construction and production, and reduces production costs.

[0018] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application, and the illustrative embodiments and descriptions thereof are used to explain this application. In the drawings: Figure 1 This is a construction flowchart for the background technology. Figure 2 This is a schematic diagram of the tunnel cross-section before the shield tunneling filling zone. Figure 3 This is a schematic diagram of the tunnel cross-section after the shield is received. Detailed Implementation

[0020] The technical solution of this application will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] like Figure 2 As shown, this application proposes a shield tunneling receiving method, which includes: constructing a mined tunnel 1, which is aligned with the travel direction of the shield tunnel 2; constructing a front sealing wall 3 at the front 1a of the mined tunnel 1; constructing a rear sealing structure 5 at the rear of the mined tunnel 1, thereby forming a cavity 4 between the front sealing wall 3 and the rear sealing structure 5; and filling the cavity 4 with filling material for receiving the shield machine.

[0022] The above method can create a closed filling zone. After the tunnel boring machine (TBM) tunnels into this zone, it can achieve pressure balance, allowing the TBM to complete the receiving work under normal tunneling conditions, thus ensuring the safe and reliable TBM receiving. At the same time, the mined tunnel 1 acts as a protective cylinder, reducing the disturbance to the soil above during the TBM receiving operation and avoiding safety accidents such as foundation collapse.

[0023] To simulate a conventional underground soil environment, the filling material preferably completely fills the cavity 4. The filling material includes one or more of the following: cohesive soil, lime-soil, graded sand and gravel, low-grade plain concrete, and foamed concrete. After filling, the density of the filling material in the cavity 4 reaches a medium-dense state or higher. After being cut and mixed by the cutterhead, this type of filling material forms a uniform and continuous plastic flow state within the soil chamber, achieving uniform pressure distribution. Simultaneously, the dense soil possesses a certain degree of self-stability, providing uniform reaction force for shield tunneling, maintaining the stability of the shield machine's posture, preventing axial deviation, and ensuring the safety of the shield structure and tunnel segments.

[0024] When the filling area is saturated, it forms an impermeable barrier, blocking external groundwater seepage channels and providing an impermeable construction environment for the tunnel boring machine (TBM) to receive the material. This avoids safety accidents such as foundation collapse caused by water and sand inrush, improving the safety of construction and production. Therefore, the construction method eliminates a large amount of dewatering work, significantly reducing production costs. Preferably, the filling material may include controllable low-strength materials, such as fluidized bed soil, low-grade plain concrete, industrial solid waste-based solidified soil, biopolymer solidified soil, clinker-free cementitious material-based solidified soil, red mud-based solidified soil, engineering slag-based solidified soil, and lightweight foamed soil.

[0025] When constructing the front sealing wall 3 at the front 1a of the mined tunnel 1, since the tunnel boring machine (TBM) needs to excavate the front sealing wall 3 in this embodiment, conventional reinforced concrete structures prevent the TBM from forming an effective cutting surface and establishing or maintaining pressure balance within the chamber. Preferably, the material of the front sealing wall 3 is a machinable material that allows the TBM to cut. Simultaneously, to prevent instability and collapse of the exposed face of the mined tunnel 1, the front sealing wall 3 should have appropriate strength. Therefore, the front sealing wall 3 includes a wall made of C25 shotcrete and a fiberglass reinforced steel frame embedded in the wall.

[0026] The aforementioned tunnel 1 includes a tunnel support structure 8. During the support construction of the tunnel 1, depending on the specific geological conditions, it is possible to choose to construct only the initial support structure 9 or continue constructing the secondary lining structure 10. After the tunnel support structure 8 is completed, the cross-sectional dimensions are checked to ensure that the inner diameter of the tunnel support structure 8 is greater than or equal to the outer diameter of the cutterhead of the tunnel boring machine, and that the two are located on the same axis.

[0027] Depending on the specific geological conditions, it may be selected whether to install a reduced-diameter support reinforcement section 11 at the front 1a of the mined tunnel 1. Here, "reduced inner diameter" refers to the thickening of the cross-section of the mined tunnel support structure 8 at the front 1a of the tunnel. This support reinforcement section 11 is arranged adjacent to the front sealing wall 3. Similarly, after the construction of the support reinforcement section 11 is completed, the end face dimensions are checked, and the inner diameter of the support reinforcement section 11 is greater than or equal to the outer diameter of the cutterhead of the tunnel boring machine.

[0028] A rear sealing structure 5 is constructed at the rear of the mined tunnel 1, thereby forming a cavity 4 between the front sealing wall 3, the rear sealing structure 5, and the mined tunnel support structure 8. This rear sealing structure 5 can participate in resisting the thrust of the tunnel boring machine. The rear sealing structure 5 is not limited to a specific form; in this embodiment, it includes a rear sealing wall 6. The rear sealing wall 6 is integrally cast, and grouting pipes are pre-embedded in its lower part. Vent holes are provided in its upper part. Controllable low-strength material is filled from bottom to top through the grouting pipes to saturate the cavity 4.

[0029] Alternatively, as another implementation, when the filling material is cohesive or non-cohesive soil, the rear sealing wall 6 is poured in layers, forming an alternating cycle with the backfilling of the filling material behind the wall. That is, after each section of the wall concrete reaches the specified strength, the corresponding area is immediately backfilled and mechanically compacted. When there is no space for mechanical compaction above, the rear sealing wall 6 is poured to the lower surface of the tunnel support structure 8, with grouting holes and venting holes reserved. Low-strength self-compacting concrete or cement-stabilized gravel and other fluid materials are used for filling to ensure complete filling of the lower voids of the tunnel 1. In order to better resist the thrust of the shield tunneling, the rear sealing structure 5 includes a sealing wall support 7, which is located on the free side of the rear sealing wall 6 to support the rear sealing wall 6.

[0030] To allow sufficient space for receiving the tunnel boring machine (TBM), the net distance between the rear sealing structure 5 and the front sealing wall 3 is greater than the length of the TBM head.

[0031] When the tunnel boring machine (TBM) reaches the position of the front sealing wall 3, the tunneling parameters must be strictly controlled to maintain a low speed and steady advance, ensuring that the cutterhead accurately tunnels into the front sealing wall 3. Subsequently, the cutter head slowly cuts into the wall and gradually enters the filling area (i.e., cavity 4). This process should be carried out under the premise of maintaining the normal thrust, torque, and earth pressure balance of the TBM, so as to enable the TBM to complete the receiving operation without stopping or changing the mode.

[0032] As the tunnel boring machine advances, the assembly of segment 12 proceeds normally. After assembly, synchronous grouting is promptly implemented, and secondary grouting can be carried out if necessary to fill the gaps between segment 12 and the filling material, ensuring the structural stability of segment 12.

[0033] After the grout behind segment 12 reaches its designed strength, the previously constructed sealing structure 5 is removed. Then, the filling material pre-filled into the cavity for stable tunneling is removed. Finally, the tunnel boring machine (TBM) is systematically disassembled, including the cutterhead, shield body, and auxiliary equipment, which are then lifted out in sections, completing the entire TBM receiving process.

[0034] like Figure 3 As shown, after clearing the working face, a shield post-cast ring beam 13 is constructed to connect the shield segment 12 and the tunnel support structure 8 into a whole. This is used to seal the gap between the shield segment 12 and the tunnel support structure 8 and prevent the infiltration of groundwater.

[0035] The preferred embodiments of this application have been described in detail above. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

[0036] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0037] Furthermore, various different embodiments of this application can be combined in any way, as long as they do not violate the spirit of this application, they should also be regarded as the content disclosed by this invention.

Claims

1. A shield receiving method, characterized in that, The shield receiving method includes: The construction of the cut-and-cover tunnel (1) is aligned with the direction of travel of the shield tunnel (2); A front sealing wall (3) is constructed at the front (1a) of the cut-and-cover tunnel (1); A rear sealing structure (5) is constructed at the rear (1b) of the cut-and-cover tunnel (1), thereby forming a cavity (4) between the front sealing wall (3) and the rear sealing structure. Filling material is filled into the cavity (4) for receiving the tunnel boring machine.

2. The shield receiving method according to claim 1, characterized in that, The filling material completely fills the cavity (4).

3. The shield receiving method according to claim 1 or 2, characterized in that, The filling material includes one or more of cohesive soil, lime soil, graded sand and gravel, low-grade plain concrete, and foamed concrete. After filling, the density of the filling material in the cavity (4) reaches a medium density state or above.

4. The shield receiving method according to claim 1, characterized in that, The filling material includes controllable low-strength materials, such as fluidized solid soil, low-grade plain concrete, industrial solid waste-based solidified soil, biopolymer solidified soil, clinker-free cementitious material-based solidified soil, red mud-based solidified soil, engineering slag-based solidified soil, and lightweight foamed soil.

5. The shield receiving method according to claim 1 or 2, characterized in that, The material of the front sealing wall (3) is a machinable material that allows the tunnel boring machine to cut.

6. The shield receiving method according to claim 5, characterized in that, The front sealing wall (3) includes a wall made of C25 shotcrete and a fiberglass reinforced steel frame embedded in the wall.

7. The shield receiving method according to claim 1 or 2, characterized in that, The construction tunnel (1) includes a construction tunnel support structure (8), the inner diameter of which is greater than or equal to the outer diameter of the cutterhead of the tunnel boring machine.

8. The shield receiving method according to claim 7, characterized in that, The tunnel support structure (8) includes a support reinforcement part (11) with a reduced inner diameter. The support reinforcement part (11) is arranged adjacent to the front sealing wall (3). The inner diameter of the support reinforcement part (11) is greater than or equal to the outer diameter of the cutterhead of the tunnel boring machine.

9. The shield receiving method according to claim 1 or 2, characterized in that, The post-sealing structure (5) includes a post-sealing wall (6).

10. The shield receiving method according to claim 9, characterized in that, The shield receiving method includes: The rear sealing wall (6) is integrally cast and formed, and a grouting pipe is pre-embedded in the lower part of the rear sealing wall (6). An exhaust hole is set in the upper part of the rear sealing wall (6). Controllable low strength material is filled from bottom to top through the grouting pipe so that the cavity (4) is saturated.

11. The shield receiving method according to claim 10, characterized in that, The rear sealing structure (5) includes a sealing wall support (7), which is located on the free side of the rear sealing wall (6) and supports the rear sealing wall (6).

12. The shield receiving method according to claim 10, characterized in that, The net distance between the rear sealing structure (5) and the front sealing wall (3) is greater than the length of the tunnel boring machine head.

Images