A construction method for simultaneously reinforcing a deep-buried risk source and shield maintenance

Abstract

The application discloses a construction method for reinforcing a deep-buried risk source and shield maintenance simultaneously, comprising the following steps: S10, finding out the position of the risk source; S20, selecting a construction area, which is located between the risk source and a shield maintenance area in the longitudinal direction and deviates to one side of the shield tunnel in the lateral direction; S30, excavating a vertical shaft in the construction area; S40, constructing a lateral cross passage between the risk source and the shield maintenance area from the vertical shaft in the lateral direction; S50, respectively constructing a longitudinal risk source reinforcing cross passage and a longitudinal shield maintenance cross passage from the lateral cross passage to the risk source and the shield maintenance area; and S60, performing a risk source reinforcing construction operation and shield maintenance. The construction method provided by the application comprehensively considers the construction requirements of the risk source reinforcement and the shield maintenance, so that the grouting reinforcement of the existing risk source and the shield cutter maintenance operation can be simultaneously performed, the construction period can be saved, the construction efficiency is improved, the construction safety hidden danger is reduced, and the smooth progress of the project is ensured.

Description

Technical Field

[0001] This invention relates to the field of tunnel boring machine (TBM) construction technology, specifically a construction method that can be used simultaneously for the reinforcement of deeply buried risk sources and the maintenance of TBMs. Background Technology

[0002] Shield tunneling operations in soft soil and soft rock strata (silt, loess, pebbles, etc.) involve numerous construction risks. Currently, shield tunneling risks are classified in several ways: by cause of the accident, by consequences, by predictability, and by the construction sequence. The second category includes damage to existing tunnels, underground pipelines, and building foundations. Failure to address these risks can result in significant casualties and property damage. To mitigate the impact on these existing structures, reinforcement is typically employed. The most common reinforcement method is grouting. When the risk source structure is shallow, grouting can be performed from the surface to the underground structure. However, when the risk source structure is deep, surface grouting is not feasible, necessitating the excavation of a shaft to a designated location for internal grouting reinforcement.

[0003] Tunnel boring machines (TBMs) rely on a motor-driven cutterhead rotation to cut through the soil at the excavation face. During TBM construction, cutter wear inevitably occurs. Proper selection and maintenance of the cutters determine the quality and progress of the tunneling project. Failure to detect and replace cutters in a timely manner will accelerate the wear of other cutters, making TBM cutter wear a critical issue affecting project quality. Therefore, it is essential to monitor the wear of the cutterhead cutters closely and conduct timely inspections and replacements during TBM construction.

[0004] Therefore, in shield tunneling, there are both potential risk sources that need to be reinforced in a timely manner and the need for shield maintenance at the same time. Sometimes, the location of the risk source overlaps with the location of the cutterhead replacement (maintenance) shaft. This means that at the target location, both risk source reinforcement and maintenance shaft excavation must be carried out. If both share the same shaft, it will cause construction conflicts (such as...). Figure 4 As shown, according to previous engineering cases, construction operations ① and ② conflict with each other; if they are carried out separately and two shafts are excavated, it will not only lead to cost waste and construction delays, but also easily cause the shaft structures to interact and become unstable. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a construction method that can be used for both the reinforcement of deeply buried risk sources and the maintenance of tunnel boring machines. By comprehensively considering the construction needs of both risk source reinforcement and tunnel boring machine maintenance, it can reduce the amount of work, save construction time, improve construction efficiency, and reduce construction safety hazards.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention first provides a construction method for simultaneously reinforcing deeply buried risk sources and performing shield tunneling maintenance, comprising the following steps: S10, identifying the location of the risk source and determining that both the risk source and the shield tunneling maintenance area are located on the shield tunnel; S20, selecting a construction area on the ground based on the site conditions, wherein the construction area is located longitudinally between the risk source and the shield tunneling maintenance area, and laterally biased towards one side of the shield tunnel; S30, excavating a vertical shaft in the construction area; S40, constructing a transverse passage from the vertical shaft to the risk source and the shield tunneling maintenance area, wherein the transverse passage is excavated at least to the location of the shield tunnel; S50, constructing a longitudinal risk source reinforcement transverse passage and a longitudinal shield tunneling maintenance transverse passage from the transverse passage to the risk source and the shield tunneling maintenance area respectively; S60, performing risk source reinforcement work using the longitudinal risk source reinforcement transverse passage, and performing shield tunneling maintenance using the longitudinal shield tunneling maintenance transverse passage.

[0010] Furthermore, in S20, the construction area is far from the risk source both longitudinally and laterally, and laterally it is located outside the coverage area of ​​the risk source and the shield tunneling maintenance area.

[0011] Furthermore, in S40 and S50, the construction transverse passage, the construction longitudinal risk source reinforcement passage, and the longitudinal shield tunnel maintenance passage are all constructed using the step method, and core soil is reserved during the step method construction process.

[0012] Furthermore, in S60, the risk source reinforcement construction operation carried out by the longitudinal risk source reinforcement transverse channel includes: S601, constructing a risk source reinforcement construction operation area in the longitudinal risk source reinforcement transverse channel towards the risk source; S602, carrying out risk source reinforcement construction operation in the risk source reinforcement construction operation area.

[0013] Furthermore, in S601, the risk source reinforcement construction work area is close to the risk source.

[0014] Furthermore, in S60, shield tunneling maintenance via the longitudinal shield tunneling maintenance transverse passage includes: S611, constructing a shield tunneling maintenance area in the direction of the shield tunneling maintenance area within the longitudinal shield tunneling maintenance transverse passage; and S612, performing shield tunneling maintenance within the shield tunneling maintenance area.

[0015] Furthermore, it also includes: S70, after the shield tunneling maintenance is completed, backfilling construction is carried out, and earthwork is backfilled into the longitudinal risk source reinforcement transverse passage to retain the longitudinal shield tunneling maintenance transverse passage.

[0016] Furthermore, the risk source reinforcement is one or more of the following: grouting reinforcement, anchor spraying reinforcement, anchor cable reinforcement, steel support reinforcement, and freezing reinforcement.

[0017] The present invention also provides a shaft-to-transverse passage combination structure for the construction method, comprising: a shaft, located longitudinally between the risk source and the shield tunnel maintenance area, and laterally biased towards one side of the shield tunnel; a transverse passage, one end of which is connected to the shaft and extends laterally from the shaft towards the risk source and the shield tunnel maintenance area, and the other end extending at least to the location of the shield tunnel; a longitudinal risk source reinforcement transverse passage, located on one side of the transverse passage on the shield tunnel, one end of which is connected to the transverse passage and the other end extending towards the risk source; and a longitudinal shield tunnel maintenance transverse passage, located on the other side of the transverse passage on the shield tunnel, one end of which is connected to the transverse passage and the other end extending towards the shield tunnel maintenance area.

[0018] Furthermore, it also includes: a risk source reinforcement construction work area, excavated at the other end of the longitudinal risk source reinforcement transverse passage and close to the risk source, for construction personnel to carry out risk source reinforcement construction work; and a shield tunneling maintenance area, excavated at the other end of the longitudinal shield tunneling maintenance transverse passage, for construction personnel to carry out shield cutterhead and tool maintenance.

[0019] (III) Beneficial Effects

[0020] This invention discloses a construction method that can be used simultaneously for the reinforcement of deeply buried risk sources and the maintenance of tunnel boring machines. This method reduces the workload, saves time, improves construction efficiency, and lowers construction safety hazards. Specifically, it has at least the following beneficial effects:

[0021] The present invention provides a construction method for both reinforcing deeply buried risk sources and maintaining shield tunnels. By excavating a vertical shaft between the risk source and the shield maintenance area in the longitudinal direction, and keeping the shaft far away from the shield tunnel, the safety of the shaft excavation is ensured, while avoiding disturbance to the risk source.

[0022] This invention provides a construction method that can be used for both deep-buried risk source reinforcement and shield tunneling maintenance. By constructing a transverse passage, it ensures that risk source reinforcement and shield tunneling maintenance can be carried out simultaneously when only one vertical shaft is excavated, saving construction time and ensuring the smooth progress of the project.

[0023] This invention provides a construction method that can be used for both deep-buried risk source reinforcement and shield tunneling maintenance. Instead of constructing the shaft on the shield tunnel between the risk source and the shield tunneling maintenance area, the shaft is located laterally off to one side of the shield tunnel. Compared to the traditional method of excavating shafts on the shield tunnel, the shaft is farther away from both the risk source and the shield tunneling maintenance area, resulting in less impact on both and greater safety, thus ensuring the safety of the construction operation.

[0024] This invention provides a construction method that can be used for both deep-buried risk source reinforcement and shield tunneling maintenance. Instead of constructing the shaft on the shield tunnel between the risk source and the shield tunneling maintenance area, the shaft is located laterally off to one side of the shield tunnel. After the shield gap is completed, only local backfilling of the transverse passage is needed to ensure the normal passage of the shield, avoiding the need for shaft backfilling and not affecting the normal passage of the shield.

[0025] Since shafts are no longer constructed on shield tunnels, their location is more flexible and less constrained. For example, when the maintenance area is located in a busy urban area, a suitable location can be chosen for the shaft, minimizing the use of surface space.

[0026] It should be understood that the implementation of any embodiment of the present invention does not mean that it will simultaneously possess or achieve multiple or all of the above-mentioned beneficial effects. Attached Figure Description

[0027] To more clearly illustrate the embodiments of the present invention or the technical solutions in 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 merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0028] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0029] Figure 1 This is a schematic diagram of the overall process of the construction method according to an embodiment of the present invention;

[0030] Figure 2 This is a schematic plan view of the vertical shaft and horizontal passage combination structure according to an embodiment of the present invention;

[0031] Figure 3 This is a flowchart illustrating the construction process of the vertical shaft lock ring beam according to an embodiment of the present invention;

[0032] Figure 4 This is a plan view illustrating the conflict between the risk source and the tunnel boring machine maintenance area. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0034] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0035] It should be understood that the terms "comprising / including," "consisting of," or any other variations are intended to cover non-exclusive inclusion, such that a product, apparatus, process, or method that comprises a list of elements includes not only those elements but may also include, where necessary, other elements not expressly listed, or elements inherent to such a product, apparatus, process, or method. Without further limitation, an element defined by the phrases "comprising / including," "consisting of," does not exclude the presence of additional identical elements in the product, apparatus, process, or method that includes said element.

[0036] It should also be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device, component or structure referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation of the present invention.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] In actual shield tunneling construction, sometimes deeply buried risk sources are encountered. These risk sources may overlap with or be located on the same tunnel alignment as the inspection (cutterhead replacement) shaft. "Deeply buried" means the risk source is buried at a considerable depth, such as the same depth as or close to the depth of the shield tunnel. In such cases, it is not suitable to directly reinforce the risk source by drilling grouting holes on the surface; reinforcement must be carried out underground. This means that both risk source reinforcement and inspection shaft excavation must be performed at the target location. If both share the same shaft, it will cause construction conflicts (e.g., ...). Figure 4 As shown, according to previous engineering cases, construction operations ① and ② conflict with each other; if they are carried out separately and two shafts are excavated, it will not only lead to cost waste and construction delays, but also easily cause the shaft structures to interact and become unstable.

[0039] Therefore, this invention proposes a construction method that can be used for both deep-buried risk source reinforcement and shield tunneling maintenance. Specifically, it is a vertical shaft + horizontal passage combined structure excavation method that can simultaneously complete deep-buried risk source reinforcement and shield tunneling maintenance, shorten the construction period, save costs, and ensure the smooth progress of the project.

[0040] To better understand the above technical solution, the following will provide a detailed explanation of the technical solution in conjunction with the accompanying drawings and specific implementation methods.

[0041] A construction method that can be used for both reinforcement of deeply buried risk sources and tunnel boring machine maintenance, see [link to relevant documentation]. Figure 1 The construction flowchart shown includes the following steps: S10, identifying the location of the risk source and designing the shield tunnel maintenance area, both of which are located on the shield tunnel; S20, selecting a construction area on the ground based on the site conditions, the construction area being located longitudinally between the risk source and the shield tunnel maintenance area, and laterally biased towards one side of the shield tunnel; S30, excavating a vertical shaft in the construction area; S40, constructing a transverse passage from the shaft to the risk source and the shield tunnel maintenance area, extending at least to the shield tunnel location; S50, constructing a longitudinal risk source reinforcement transverse passage and a longitudinal shield tunnel maintenance transverse passage from the transverse passage to the risk source and the shield tunnel maintenance area respectively; S60, carrying out risk source reinforcement work through the longitudinal risk source reinforcement transverse passage, and performing shield tunnel maintenance through the longitudinal shield tunnel maintenance transverse passage.

[0042] In this invention, the location of the risk source is first identified. Risk sources include existing tunnels, existing underground pipelines, and existing building foundations. When a risk source is located within a shield tunnel, failure to take appropriate measures could result in significant casualties and property damage. In existing construction processes, to reduce the impact of shield tunneling on these existing structures, reinforcement methods are typically employed. The most common reinforcement method is grouting. When the risk source structure is shallow, grouting can be performed from the surface to the underground. However, when the risk source structure is deep, surface grouting is not feasible; instead, a vertical shaft must be excavated to the designated location, followed by in-tunnel grouting reinforcement.

[0043] Since both the risk source and the shield tunneling maintenance area are located on the shield tunnel, constructing the vertical shaft along the tunnel's direction between these two areas would minimize the excavation work for the transverse passage. However, subsequent shield tunneling would require crossing both the risk source and maintenance area, necessitating backfilling or reinforcement of the vertical shaft to meet construction requirements. This wastes both funds and time. Conversely, constructing the vertical shaft adjacent to the tunnel and then building the transverse passage only requires partial backfilling to ensure normal shield tunneling. Therefore, this invention selects the construction area longitudinally between the risk source and the shield tunneling maintenance area, and laterally biased towards one side of the shield tunnel. Figure 2 On the right side of the middle.

[0044] With the help of the transverse passage, since the shaft is biased to one side of the shield tunnel in the horizontal direction, the shaft will not affect the risk source and the shield maintenance area. This also allows the shield maintenance area to be set up as close as possible to the location of the risk source. The risk source reinforcement and shield maintenance can be completed at the same time by excavating the shortest shield maintenance transverse passage.

[0045] The shield tunneling maintenance area is also located on the shield tunnel, and is used for the maintenance and replacement of the shield cutterhead and cutting tools when the shield tunneling reaches this location.

[0046] See Figure 2 The construction area is located far from the risk source both longitudinally and laterally, and laterally outside the coverage area of ​​the risk source and the shield tunneling maintenance area, in order to minimize or reduce the disturbance to the risk source structure caused by subsequent shaft excavation. The specific distance should be determined by the construction unit based on a comprehensive consideration of factors such as the shield tunneling diameter, the shaft excavation diameter, the surrounding surface environment, and underground pipelines.

[0047] In this invention, the excavation of the vertical shaft mainly includes the construction of the shaft lock ring beam, which mainly includes the processes of surveying and setting out, earthwork excavation, rebar tying, formwork erection, and concrete pouring.

[0048] In this invention, the transverse passages for construction, as well as the longitudinal risk source reinforcement passages and the longitudinal shield tunnel maintenance passages, are all constructed using the step method. During the step method construction, core soil is reserved to prevent excessive ground settlement during excavation from affecting the structure and the ground surface. During the construction of the transverse passages, good ventilation inside the tunnel is ensured, with fresh air supplied by ventilation fans and ventilation ducts within the shaft area.

[0049] In this invention, the risk source reinforcement construction operation by the longitudinal risk source reinforcement transverse channel further includes: constructing a risk source reinforcement construction operation area in the direction of the risk source within the longitudinal risk source reinforcement transverse channel; and carrying out risk source reinforcement construction operations within the risk source reinforcement construction operation area.

[0050] The risk source reinforcement work area is located close to the risk source to facilitate the reinforcement work carried out by construction personnel. The excavation size of the longitudinal risk source reinforcement cross passage is relatively small, just enough to allow passage for personnel and construction equipment. The risk source reinforcement work area can be a larger excavation space than the longitudinal risk source reinforcement cross passage to meet the requirements of the construction personnel to carry out reinforcement work.

[0051] In this invention, the risk source reinforcement is carried out by grouting reinforcement, especially by deep hole grouting for formation reinforcement.

[0052] In this invention, shield tunneling maintenance via a longitudinal shield tunneling maintenance cross passage includes: constructing a shield tunneling maintenance area within the longitudinal shield tunneling maintenance cross passage towards the shield tunneling maintenance area; and conducting shield tunneling maintenance within the shield tunneling maintenance area. Similarly, the excavation size of the longitudinal shield tunneling maintenance cross passage is relatively small, just enough to allow passage for personnel and construction equipment. The shield tunneling maintenance area can be a larger excavation space than the longitudinal shield tunneling maintenance cross passage, to meet the operational requirements for personnel to perform shield cutterhead and tool replacement maintenance within it.

[0053] In this invention, after the risk source reinforcement and shield tunneling maintenance are completed, backfilling is carried out by backfilling earth into the longitudinal risk source reinforcement transverse passage. After the longitudinal risk source reinforcement transverse passage is backfilled, the longitudinal shield tunneling maintenance transverse passage is retained for subsequent continuous shield machine advancement. Thus, only the longitudinal risk source reinforcement transverse passage needs to be backfilled to ensure normal shield tunneling; there is no need to backfill the longitudinal shield tunneling maintenance transverse passage or the vertical shaft, reducing the workload, ensuring normal shield tunneling, and improving construction efficiency.

[0054] Of course, during backfilling, the risk source reinforcement construction area at the end of the longitudinal risk source reinforcement cross passage should also be backfilled.

[0055] See also Figure 2 The present invention further provides a vertical shaft horizontal passage combination structure involved in the construction method, comprising:

[0056] The vertical shaft is located longitudinally between the risk source and the shield tunnel maintenance area, and laterally it is biased towards one side of the shield tunnel.

[0057] The transverse passage connects to the vertical shaft at one end and extends laterally from the vertical shaft between the risk source and the shield tunnel maintenance area, while the other end extends at least to the location of the shield tunnel.

[0058] The longitudinal risk source reinforcement transverse passage and the risk source reinforcement construction work area are located on one side of the transverse transverse passage on the shield tunnel. One end of the longitudinal risk source reinforcement transverse passage is connected to the transverse transverse passage, and the other end is connected to the risk source reinforcement construction work area. The risk source reinforcement construction work area is used by construction personnel to carry out risk source reinforcement construction work.

[0059] The longitudinal shield tunnel maintenance cross passage and shield maintenance area are located on the other side of the transverse cross passage on the shield tunnel. One end of the longitudinal shield tunnel maintenance cross passage is connected to the transverse cross passage, and the other end is connected to the shield maintenance area. The shield maintenance area is used by construction personnel to carry out maintenance and repair of the shield cutterhead and tools.

[0060] In locations far from existing structures, vertical shafts are excavated to clear underground mud or silt, creating a platform for subsequent construction work and also serving as ventilation openings.

[0061] The transverse passage serves to connect the risk source reinforcement construction area and the shield tunneling maintenance area simultaneously.

[0062] The longitudinal risk source reinforcement transverse passage provides a channel for transporting equipment and materials for the grouting reinforcement operation of existing risk sources.

[0063] The longitudinal tunnel maintenance cross passage provides a channel for transporting equipment and materials for the replacement (maintenance) of the cutterhead cutters of the tunnel boring machine.

[0064] In this invention, the cross-sectional dimensions of the longitudinal risk source reinforcement cross passage and / or the longitudinal shield tunnel maintenance cross passage are smaller than those of the transverse cross passage. This reduces the amount of excavation work required for the longitudinal risk source reinforcement cross passage and / or the longitudinal shield tunnel maintenance cross passage, allowing passage for personnel and construction equipment. Since backfilling is still required later, the amount of backfilling work can also be reduced.

[0065] The risk source reinforcement construction work area (grouting area) is located at the corresponding location of the risk source, such as below existing tunnels, existing underground pipelines, existing building structure foundations, etc., and is the work area for construction personnel to carry out grouting reinforcement.

[0066] The shield tunneling maintenance area is the work area where construction workers inspect and maintain the cutterhead and cutting tools of the shield tunneling machine.

[0067] Engineering applications:

[0068] The section between Niujie Station and Financial Street Station has two lines: the right line runs from K41+720.402 to K43+604.139, with a total length of 1883.737m; the left line runs from K41+720.402 to K43+604.139, with a total length of 1883.854m (including a 0.117m long chain). This section passes under the underground tunnel section between Fuxingmen Station and Xidan Station of Metro Line 1. Prior to the tunnel crossing, shield tunneling inspection and grouting reinforcement of the existing soil beneath the Line 1 section are required.

[0069] Based on the surrounding environment of the underpass section, a construction area was selected within the green space in the southeast quadrant of the intersection of Fuxingmennei Street and Naoshikou Street. A vertical shaft was constructed, along with a cross passage and a shield tunneling maintenance area. The shield tunneling machine cutterhead will be inspected before passing under the Fuxingmen Station to Xidan Station section of Line 1. The deep-hole grouting reinforced mining method will be used for construction. The vertical shaft dimensions are 6.2m × 4.4m (length × width), with a depth of 21.24m, and the inverted shaft wall method will be used. The grouting reinforced cross passage dimensions are 4.1m × 3.6m (width × height), 4.1m × 4.6m (width × height), and 5.6m × 4.1m (width × height), constructed using the step method. The shield tunneling maintenance cross passage dimensions are 3.1m × 3.1m (width × height), 3.1m × 4.3m (width × height), and 3.6m × 3.1m (width × height), constructed using the step method.

[0070] 1. Shaft construction

[0071] The construction of the shaft lock ring beam mainly includes surveying and setting out, earthwork excavation, rebar tying, formwork erection, and concrete pouring. See the construction process flow chart below. Figure 3 The details are as follows.

[0072] (1) Excavation and shotcrete support of the lock ring beam

[0073] Draw the outline of the grouting shaft excavation on the ground according to the design dimensions in the drawings. Use mechanical excavation with manual assistance for finishing. Excavation must be carried out strictly according to the outline to avoid under-excavation and large-bottom excavation. Excavate in steps. After the excavation is formed, manually clean and level the bottom. Shotcrete a thick cushion layer is sprayed on the bottom of the pit. Steel mesh is hung on the vertical surface and shotcrete is sprayed for support.

[0074] (2) Binding of reinforcement bars for lock-joint ring beam

[0075] Within 0.8m below ground level, there is a 1.5m wide concrete interlocking ring beam, and the reinforcement binding is strictly carried out according to the design specifications in the drawings. The concrete retaining wall of the grouting shaft has a specification of 1000mm (height) × 200mm (thickness), located on the outside of the construction shaft. A guardrail is installed at the top of the retaining wall, and a drainage ditch is installed behind it. The reinforcement requirements for the concrete retaining wall are as follows:

[0076] ① The welding length of the reinforcing bars shall meet the requirement of 10d for single-sided welding, and the lap length of the reinforcing bars shall not be less than 35d; the anchorage length of the stressed reinforcing bars shall not be less than 35d, and the main reinforcing bars of the inner concrete retaining wall of the lock ring beam and the wellhead section shall be anchored into the concrete.

[0077] ② The distance from the end of the lap length to the bend of the reinforcing bar shall not be less than 10 times the diameter of the reinforcing bar. The upper reinforcing bar splice shall be located at 1 / 3 of the span, and the lower reinforcing bar splice shall be located at the support.

[0078] ③ Prepare tying tools and materials such as 20# to 22# heat-resistant wire and rebar hooks, and prepare cement mortar spacers according to the thickness of the protective layer of each part. The net protective layer thickness of the rebar in the lock ring beam shall not be less than 40mm.

[0079] ④ When pouring concrete, a dedicated person must be on duty to correct any displacement or loosening of the reinforcing bars in a timely manner.

[0080] ⑤ Before concrete pouring, pre-embed the foundation of the lifting well frame, the steel pipe of the wellhead guardrail, and the pre-embedded parts of the pedestrian escalator.

[0081] (3) Concrete pouring

[0082] After the reinforcement of the lock-type ring beam is tied, the formwork is erected, and the formwork is inspected and approved by the supervisor, the concrete pouring of the lock-type ring beam is carried out. The lock-type ring beam and the concrete retaining wall of the wellhead section are poured in one go. When pouring concrete, the vertical connecting bars of the reserved vertical shaft steel grid should be installed to ensure the excavation of the well body. At the same time, care should be taken to ensure that the pre-embedded bolts of the lifting frame are vertical and well protected. The concrete is poured using a 5cm immersion vibrator, and the vibration should follow the principle of quick insertion and slow withdrawal. The lock-type ring beam is poured in one go, but in layers, with the thickness of each layer controlled at about 300-500mm. The time between layers should be minimized to avoid cold joints. During the concrete pouring process, the height difference between the concrete pouring surfaces on both sides should not exceed 0.5 meters to avoid excessive deviation that could cause the overall displacement of the scaffolding support system.

[0083] 2. Grouting reinforcement of risk sources

[0084] To control the settlement of underground pipelines and ensure that surface settlement, pipeline settlement, and the settlement of the tunnel arch and structural convergence are within allowable ranges, thus guaranteeing the safety of the pipelines and structures, deep-hole grouting is employed for ground reinforcement. Pre-grouting is performed on the strata surrounding the initial support structure to form a partial reinforcement ring, reducing the disturbance to surrounding pipelines caused by the initial support structure construction and effectively controlling the settlement and deformation of the surrounding pipelines.

[0085] The deep-hole grouting process has a longitudinal length of 12m and employs a double-tube backward grouting technique. Each hole is continuously grouted at four angles, with a circumferential spacing of 900mm between grouting holes and a planned grout diffusion radius of 600mm. Grouting parameters will be determined based on field test results, and monitoring and measurement will be strengthened to avoid damage to existing buildings and structures.

[0086] To prevent cross-grouting, measures such as grouting between holes or increasing the spacing between skip holes should be taken. Before formal grouting construction, 1-2 holes should be tested to check and adjust the grouting parameters. Attention should be paid to timely adjustment of the grout mix ratio and pressure to ensure good grouting effect.

[0087] 3. Earthwork backfilling

[0088] After the shield cutterhead is inspected and repaired, the earthwork backfilling process will be carried out, using well-graded crushed stone and fine sand. After the grouting reinforcement of the cross passage is completed and backfilled, the shield inspection cross passage will be retained for subsequent continuous advancement of the shield machine.

[0089] 4. Application benefits

[0090] By adopting this construction technique in the Niujie Station to Financial Street Station section, the shield cutterhead and cutting tools can be repaired smoothly while the risk sources are reinforced. This not only avoids waste of costs, but also improves construction efficiency, saves construction time, and ensures construction safety, resulting in good social benefits.

[0091] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0092] While several specific implementation details are included in the foregoing discussion, these should not be construed as limiting the scope of the invention. Certain features described in the context of individual embodiments may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented individually or in any suitable sub-combination in multiple implementations.

Claims

1. A construction method for simultaneously reinforcing deeply buried risk sources and inspecting tunnel boring machines, characterized in that, Includes the following steps: S10, Identify the location of the risk source and determine that both the risk source and the shield tunnel maintenance area are located on the shield tunnel; S20. Based on the site conditions, a construction area is selected on the ground. The construction area is located longitudinally between the risk source and the shield tunnel maintenance area, and laterally biased towards one side of the shield tunnel. The construction area is far away from the risk source both longitudinally and laterally, and laterally located outside the coverage area of ​​the risk source and the shield tunnel maintenance area. S30, excavating a vertical shaft in the construction area; S40, a transverse passage is constructed from the vertical shaft between the risk source and the shield tunnel maintenance area, and the transverse passage is excavated at least to the location of the shield tunnel. S50, the transverse passages are used to construct longitudinal risk source reinforcement transverse passages and longitudinal shield maintenance transverse passages to the risk source and shield maintenance area, respectively. S60, risk source reinforcement construction is carried out by the longitudinal risk source reinforcement transverse passage, and shield tunneling is repaired by the longitudinal shield tunneling maintenance transverse passage. S70 After the tunnel boring machine (TBM) is repaired, backfilling will be carried out. Earthwork will be backfilled into the longitudinal risk source reinforcement transverse passage, and the longitudinal TBM repair transverse passage will be preserved.

2. The construction method according to claim 1, characterized in that, In S40 and S50, the construction transverse passage, the construction longitudinal risk source reinforcement passage, and the longitudinal shield tunnel maintenance passage are all constructed using the step method, with core soil reserved during the step method construction process.

3. The construction method according to claim 1, characterized in that, In S60, the risk source reinforcement construction work carried out by the longitudinal risk source reinforcement transverse passage includes: S601, construct the risk source reinforcement work area in the longitudinal risk source reinforcement transverse channel in the direction of the risk source; S602, carry out risk source reinforcement construction work in the risk source reinforcement construction work area.

4. The construction method according to claim 3, characterized in that, In S601, the risk source reinforcement construction work area is close to the risk source.

5. The construction method according to claim 1, characterized in that, In S60, shield tunneling maintenance via the longitudinal shield tunneling maintenance transverse passage includes: S611, Construct the shield maintenance area in the longitudinal shield maintenance transverse passage towards the shield maintenance area; S612, Shield tunneling maintenance is carried out within the shield tunneling maintenance area.

6. The construction method according to any one of claims 1 to 5, characterized in that, The risk source reinforcement includes one or more of the following: grouting reinforcement, anchor spraying reinforcement, anchor cable reinforcement, steel support reinforcement, and freezing reinforcement.

7. A vertical shaft transverse passage assembly structure for use in the construction method according to any one of claims 1 to 6, characterized in that, include: The vertical shaft is located longitudinally between the risk source and the shield tunnel maintenance area, and laterally it is biased towards one side of the shield tunnel. A transverse passage, one end of which is connected to the vertical shaft and extends laterally from the vertical shaft between the risk source and the shield tunnel maintenance area, and the other end extends at least to the location of the shield tunnel. The longitudinal risk source reinforcement transverse channel is located on one side of the transverse transverse channel on the shield tunnel. One end of the longitudinal risk source reinforcement transverse channel is connected to the transverse transverse channel, and the other end extends towards the risk source. The longitudinal shield tunnel maintenance transverse passage is located on the other side of the transverse transverse passage on the shield tunnel. One end of the longitudinal shield tunnel maintenance transverse passage is connected to the transverse transverse passage, and the other end extends into the shield tunnel maintenance area.

8. The vertical shaft and horizontal passage combination structure according to claim 7, characterized in that, Also includes: The risk source reinforcement construction work area is excavated at the other end of the longitudinal risk source reinforcement transverse channel and close to the risk source, for construction personnel to carry out risk source reinforcement construction work; The shield tunneling maintenance area is excavated at the other end of the longitudinal shield tunneling maintenance cross passage, and is used by construction personnel to inspect and maintain the shield cutterhead and cutting tools.

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