Method for disassembling center block of double-shield TBM (tunnel boring machine) in tunnel

Abstract

The invention relates to a double-shield TBM center block in-hole dismounting method. The method comprises the following steps that S1, construction preparation and shield body cutting are conducted; s2, arranging lifting points; s3, the bolt is detached and separated from the center block; s4, the center block is preliminarily hoisted and moved backwards; s5, turning over the center block; and S6, reinforcing and transporting. The method has the advantages that through the arrangement of the lifting points and the cooperative operation process, the problem that the cutter head center block with the large size is disassembled in a shield body is solved, it is ensured that parts can be used for the second time after going out of a hole, and the economic value of the parts is protected.

Description

Technical Field

[0001] This invention relates to a method for dismantling a double-shield TBM central block cavity, belonging to the field of dismantling. Background Technology

[0002] The double-shield hard rock tunnel boring machine (TBM) is a highly efficient tunnel construction equipment that integrates excavation, support, and muck removal. Taking a model with an excavation diameter of Φ6300mm as an example, its overall length can reach over 100 meters, and the main unit can weigh hundreds of tons. In traditional tunnel construction projects, after completing the tunnel excavation task, the TBM will drive out of the tunnel and be systematically dismantled in a pre-constructed, spacious dismantling chamber or launching shaft using large lifting equipment (such as truck cranes or gantry cranes). This method has the advantages of ample working space and convenient hoisting.

[0003] However, as urban subway construction extends to existing operating stations and core urban areas, the construction environment is becoming increasingly complex. To address challenges such as connecting to existing stations, extremely limited construction sites, shortening construction periods, and reducing demolition, a need has emerged for TBM dismantling to be completed inside the tunnel (tunnel), namely the "in-tunnel shell disposal and dismantling" solution. In this solution, the massive 40-ton cutterhead center block, as the core component of the TBM, is crucial. Whether it can be safely and undamagedly dismantled and transported out within a confined space becomes the most critical step determining the success or failure of the entire dismantling plan. This directly relates to whether this core component can be reused in subsequent projects, and has significant economic value.

[0004] Currently, there are no mature and reliable precedents or experiences to draw upon, either domestically or internationally, for disassembling the cutterhead center block of a double-shield TBM inside a tunnel. Given the lack of open space and large lifting equipment, and facing multiple challenges such as the large weight and volume of the center block, extremely limited working space inside the tunnel, and high safety risks, designing a safe, reliable, efficient disassembly method that ensures the integrity of the components has become a critical technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a method for disassembling the central block of a dual-shield TBM. The technical solution of this invention is as follows: A method for dismantling a dual-shield TBM's central block cavity includes the following steps: Step S1, Construction Preparation and Shield Cutting: Partially cut the front shield of the double-shield TBM to provide space for subsequent hoisting operations, and pre-set lifting points on the shield flange plate retained after cutting; Step S2, Lifting Point Arrangement: Several lifting points are set on the annular flange plates of the front shield and the support shield; at the same time, several lifting lugs are bolted to the flange surface around the center block of the cutterhead as lifting points for the center block; Step S3, Bolt removal and center block separation: Remove the flange connecting bolts connecting the center block and the side block of the cutter head, as well as the double-ended studs connecting the center block and the main drive unit, so that the center block can be completely separated. Step S4, Initial hoisting and relocation of the center block: Using the lifting points set in step S2, the separated center block is lifted and supported by an electric hoist, and then the center block is moved to the telescopic shield area by a transport trolley. Step S5, Flip the center piece: Within the telescopic shield area, the lifting points on the front shield are connected to the upper lifting points of the center block, and the lifting points on the support shield are connected to the lower lifting points of the center block. By controlling the alternating tensioning and relaxation of several electric hoists, the coordinated action gradually flips the radially upright cutter head center block and finally places it horizontally on the transport trolley. Step S6, Reinforcement and Transportation: The center block, which is placed horizontally on the transport trolley, is reinforced to prevent slipping and tipping, and then safely transported out of the hole by traction.

[0006] In step S2, a lifting point is set at the left and right positions directly above the annular flange plate of the front shield; and a lifting point is set at the left and right positions 50 degrees above the annular flange plate at the rear end of the support shield.

[0007] In step S2, lifting lugs are provided on the center block of the cutter head, specifically including: two lifting points, an upper left lifting point and an upper right lifting point, are provided at a position 50 degrees to the left and right directly above the flange, and two lifting points, a lower left lifting point and a lower right lifting point, are provided at a position 50 degrees to the left and right directly below the flange.

[0008] The turning-over operation in step S5 specifically includes the following steps: S5.1: Use the left and right lifting points on the front shield to connect and tension the upper left and upper right lifting points on the upper part of the center block via an electric hoist, so that the center block is suspended in the air; S5.2: Use the left and right lifting points on the support shield to connect with the lower left and lower right lifting points of the center block via an electric hoist; S5.3: Simultaneously tension the electric hoist on the support shield and simultaneously loosen the electric hoist on the front shield, so that the bottom of the center block is lifted and the whole structure changes from a vertical state to an inclined state. S5.4: When tilting to the bottom, there is enough space for the transport trolley to run, move the transport trolley to below the center block; S5.5: Continue to alternately operate the electric hoists on the front shield and the support shield until the center block is placed completely horizontally on the transport trolley.

[0009] In step S1, when making partial cuts to the front shield, the cutting position is located above the shield body, and a portion of the flange plate structure is reserved for setting up lifting points during the cutting process.

[0010] The transport trolley travels on a track laid inside the shield.

[0011] Throughout the dismantling process, no additional lifting points were set up, and no chamber expansion was carried out. The shield structure of the dual-shield TBM itself was used as the support foundation for all lifting operations.

[0012] A 30-ton lifting point is set on the left and right sides directly above the annular flange plate of the front shield; a 20-ton lifting point is set on the left and right sides 50 degrees above the annular flange plate at the rear end of the support shield.

[0013] The advantages of this invention are: 1. By optimizing the arrangement of lifting points and the collaborative operation process, the problem of disassembling the massive central block of the cutterhead inside the shield body was solved, ensuring that the components could be reused after exiting the tunnel, thus protecting their economic value.

[0014] 2. There is no need to excavate additional hoisting chambers or widen existing tunnels, nor is it necessary to introduce large external hoisting equipment. Instead, the robust front shield and support shield structure of the TBM itself are creatively used as hoisting support points, which greatly saves construction costs and time and improves dismantling efficiency.

[0015] 3. Through scientific arrangement of lifting points, welding and flaw detection processes, and coordinated "loosening and tightening" turning operations, the entire disassembly process was precisely controlled, effectively avoiding huge safety risks such as the tipping and collision of heavy objects in narrow spaces, and ensuring the safety of personnel and equipment.

[0016] 4. It solved the problem of TBM dismantling in special working conditions such as urban center areas and tunnel ends where conventional receiving conditions are not available, and provided a complete and feasible technical solution for similar projects such as subway extensions connecting to operating stations and projects with limited construction space. It is of pioneering significance in the field of urban rail construction in China.

[0017] 5. Compared with traditional tunnel-exit dismantling or destructive dismantling methods, this technology not only directly saves huge costs for tunnel construction, equipment hoisting and component replacement, but also generates huge social benefits by avoiding land acquisition and demolition and shortening the construction period, providing technical support for promoting rail transit construction in complex urban environments. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0019] This invention relates to a method for dismantling a double-shield TBM central block cavity, comprising the following steps: Step S1, Construction Preparation and Shield Cutting: Partially cut the front shield of the double-shield TBM to provide space for subsequent hoisting operations, and pre-set lifting points on the shield flange plate retained after cutting; Step S2, Lifting Point Arrangement: Several lifting points are set on the annular flange plates of the front shield and the support shield; at the same time, several lifting lugs are bolted to the flange surface around the center block of the cutterhead as lifting points for the center block; Step S3, Bolt removal and center block separation: Remove the flange connecting bolts connecting the center block and the side block of the cutter head, as well as the double-ended studs connecting the center block and the main drive unit, so that the center block can be completely separated. Step S4, Initial hoisting and relocation of the center block: Using the hoisting points set in step S2, the separated center block is hoisted and supported by an electric hoist, and then the center block is moved to the telescopic shield area by a transport trolley. Step S5, Turning the center block over: In the telescopic shield area, connect the lifting point on the front shield to the upper lifting point of the center block, and connect the lifting point on the support shield to the lower lifting point of the center block; by controlling the alternating tensioning and relaxation of several electric hoists, the center block of the cutter head, which is in a radially upright state, is gradually turned over and finally placed horizontally on the transport trolley. Step S6, Reinforcement and Transportation: The center block, which is placed horizontally on the transport trolley, is reinforced to prevent slipping and tipping. The center block is then safely transported out of the hole by traction.

[0020] This invention creatively transforms the robust shield body (front shield and support shield) of the TBM into a natural lifting load-bearing structure. Through local cutting and pre-setting of lifting points, it provides a stable and reliable working foundation for heavy components without relying on external lifting equipment or additional excavation chambers.

[0021] By utilizing the telescopic shield area for coordinated overturning operations, the high-risk posture changes are transformed into a series of controllable micro-movements, thus mitigating the risk of overturning.

[0022] The ultimate goal and direct benefit of this method is to ensure that the expensive cutter head center block is ready for reassembly and use after exiting the hole. All steps are designed with the protection of components in mind. Through non-destructive disassembly and safe handling and transportation processes, the method directly avoids the huge replacement costs caused by component damage, resulting in extremely significant economic benefits.

[0023] In step S2, a 30-ton lifting point is set on the left and right sides directly above the annular flange plate of the front shield; and a 20-ton lifting point is set on the left and right sides at 50 degrees above the annular flange plate at the rear end of the support shield.

[0024] The main load-bearing lifting points (30-ton class) are positioned directly above the thickest (100mm) and most rigid front shield annular flange plate, matching the actual stress state where most of the weight of the central block is borne by the upper lifting points. This point layout design based on mechanical principles ensures the inherent stability and reliability of the lifting system.

[0025] By setting high-tonnage lifting points on the front shield to bear the main weight, and setting auxiliary lifting points (20-ton class) on the support shield to work together, a spatial dual-support point force system is formed. This division of labor not only rationally distributes the load and avoids overloading of a single structure, but also provides the necessary torque control basis for the smooth turning of the central block, which is a prerequisite for achieving controllable turning.

[0026] The support shield lifting point is positioned 50 degrees to the left and right above the flange plate, a very ingenious spatial layout. It avoids the equipment and structure directly below, leaving space for operation and ensuring the optimal force angle when the lifting slings are connected to the lower lifting point of the center block. This effectively prevents the hoist chain from colliding or jamming with the shield or the center block itself during the turning process.

[0027] In step S2, lifting lugs are provided on the center block of the cutter head, specifically including: two lifting points, an upper left lifting point and an upper right lifting point, are provided at a position 50 degrees to the left and right directly above the flange, and two lifting points, a lower left lifting point and a lower right lifting point, are provided at a position 50 degrees to the left and right directly below the flange.

[0028] In step S2, four lifting lugs are set at specific positions on the center block of the cutter head. The advantages of this are: By symmetrically arranging four lifting points—upper left, upper right, lower left, and lower right—both vertically (directly above and below) and horizontally (50 degrees off each), on the central block flange, these points, together with the corresponding front and rear lifting points on the shield body, form a spatial equilibrium force system. This layout ensures that during subsequent turning operations, the center of gravity of the central block is always effectively constrained within the stable geometric area formed by the four lifting points. This allows for precise and stable adjustment of the spatial attitude of the massive component by controlling the tension at each point, avoiding the risks of single-point stress, swaying, or loss of control.

[0029] The lifting lug base plate is welded perpendicular to the flange plate, ensuring that when the lifting lug is under stress, the direction of the force is perpendicular to the plane of the weld seam. This primarily transforms the force into pressure or tension on the weld seam, rather than shear force, greatly improving the load-bearing capacity and reliability of the weld seam. After welding, non-destructive testing can eliminate potential defects such as internal porosity, slag inclusions, or incomplete penetration.

[0030] The four-point design perfectly matches the turning steps of "lifting the front shield lifting point and lowering the support shield lifting point", which makes the lifting function and dismantling process seamlessly connected. While realizing the operation, it ensures the efficiency of the dismantling process and the integrity of the components themselves.

[0031] The turning-over operation in step S5 specifically includes the following steps: S5.1: Use the left and right lifting points on the front shield to connect and tension the upper left and upper right lifting points on the upper part of the center block via an electric hoist, so that the center block is suspended in the air; S5.2: Use the left and right lifting points on the support shield to connect with the lower left and lower right lifting points of the center block via an electric hoist; S5.3: Simultaneously tension the electric hoist on the support shield and simultaneously loosen the electric hoist on the front shield, so that the bottom of the center block is lifted and the whole structure changes from a vertical state to an inclined state. S5.4: When tilting to the bottom, there is enough space for the transport trolley to run, move the transport trolley to below the center block; S5.5: Continue to alternately operate the electric hoists on the front shield and the support shield until the center block is placed completely horizontally on the transport trolley.

[0032] In step S1, when making partial cuts to the front shield, the cutting position is located above the shield body, and a portion of the flange plate structure is reserved for setting up lifting points during the cutting process.

[0033] The transport trolley travels on a track laid inside the shield.

[0034] Throughout the dismantling process, no additional lifting points were set up, and no chamber expansion was carried out. The shield structure of the dual-shield TBM itself was used as the support foundation for all lifting operations.

[0035] In step S5, the flipping operation of the cutter head center block is the core step, which achieves the following advantages: By coordinating the operation of two sets of electric hoists on the front shield and the support shield, the trajectory of the 40-ton weight was guided. Finally, inside the shield, which is only about 6.3 meters in diameter, the weight was safely and smoothly turned 180 degrees from upright to flat, solving the operational problem of dismantling inside the tunnel.

[0036] The entire overturning process relies entirely on the stable spatial force system formed by four pre-set lifting points: the upper left, upper right, lower left, and lower right. During operation, the weight of the central block and the overturning torque are scientifically distributed to the two independent load-bearing structures, the front shield and the support shield. The balance of the force system is regulated by controlling the length of the lifting chains, thereby transforming the risk of overturning into a controllable mechanical process.

[0037] From the pre-tensioning in S5.1 to ensure initial stability, to the coordinated action initiating the flipping in S5.3, to the timely introduction of the transport trolley in S5.4, and finally to the precise placement in S5.5, a smooth operational loop is formed. This not only ensures the safety and reliability of this construction project but also makes the technology valuable for promotion and reuse in subsequent similar projects.

[0038] This invention provides a method for dismantling the central block of a double-shield TBM inside the tunnel. It transforms the TBM's shield structure into a complete hoisting platform, and through step design and mechanical control, achieves the safe dismantling and transfer of heavy core components within the extremely confined tunnel space. Its working principle is as follows: Phase 1: (corresponding to steps S1-S2) By precisely cutting the front shield in certain areas, operational space was created while preserving the main load-bearing structure. The remaining flange plates were then converted into natural lifting bases. Subsequently, a 30-ton main lifting point was installed directly above the front shield, and a 20-ton auxiliary lifting point was installed at a 50-degree angle above the support shield, forming a tiered load-bearing system. Correspondingly, four lifting points—upper left, upper right, lower left, and lower right—were symmetrically arranged on the flange surface of the cutterhead center block. Vertical welding and non-destructive testing ensured reliable connections.

[0039] Phase Two: (Corresponding to steps S3-S4) After all connecting bolts were removed, the central block was hoisted and stabilized using the pre-assembled hoisting system. This ensured that the 40-ton core component was completely under control the moment it was disconnected from the structural connections, eliminating the risk of instability. The central block was then precisely transferred to the telescopic shield area using a transport trolley.

[0040] Phase 3: (corresponding to step S5) Initial suspension stability is achieved by connecting the front shield lifting point with the upper lifting point of the center block; Then, a flipping torque control system is established by connecting the support shield lifting point and the lower lifting point; Through coordinated control of upper tension and lower tension: the hoist of the support shield is tensioned simultaneously to raise the bottom, while the hoist of the front shield is relaxed to lower the top. The torque difference generated by the two independent shields drives the central block to achieve a smooth attitude change around its center of gravity. When tilted to a predetermined angle, a transport trolley is introduced, and the safe load transfer is finally completed through precise adjustment of the electric hoist.

[0041] Phase 4: (corresponding to step S6) By reinforcing the center block with anti-rollover measures, the central block and the transport trolley are integrated into a stable transport unit, which is then safely transported out of the tunnel via a track system, achieving the lossless recycling of the core components.

[0042] This invention overcomes the challenge of disassembling heavy components in confined spaces by combining the structural characteristics of the TBM with hoisting technology. The entire process achieves disassembly within the tunnel without relying on external hoisting equipment or requiring tunnel expansion.

[0043] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for disassembling a double-shield TBM's central block cavity, characterized in that, Includes the following steps: Step S1, Construction Preparation and Shield Cutting: Partially cut the front shield of the double-shield TBM to provide space for subsequent hoisting operations, and pre-set lifting points on the shield flange plate retained after cutting; Step S2, Lifting Point Arrangement: Several lifting points are set on the annular flange plates of the front shield and the support shield; at the same time, several lifting lugs are bolted to the flange surface around the center block of the cutterhead as lifting points for the center block; Step S3, Bolt removal and center block separation: Remove the flange connecting bolts connecting the center block and the side block of the cutter head, as well as the double-ended studs connecting the center block and the main drive unit, so that the center block can be completely separated. Step S4, Initial hoisting and relocation of the center block: Using the lifting points set in step S2, the separated center block is lifted and supported by an electric hoist, and then the center block is moved to the telescopic shield area by a transport trolley. Step S5, Flip the center piece: Within the telescopic shield area, the lifting points on the front shield are connected to the upper lifting points of the center block, and the lifting points on the support shield are connected to the lower lifting points of the center block. By controlling the alternating tensioning and relaxation of several electric hoists, the coordinated action gradually flips the radially upright cutter head center block and finally places it horizontally on the transport trolley. Step S6, Reinforcement and Transportation: The center block, which is placed horizontally on the transport trolley, is reinforced to prevent slipping and tipping, and then safely transported out of the hole by traction.

2. The method for dismantling the central block of a dual-shield TBM according to claim 1, characterized in that, In step S2, a lifting point is set at the left and right positions directly above the annular flange plate of the front shield; and a lifting point is set at the left and right positions 50 degrees above the annular flange plate at the rear end of the support shield.

3. The method for dismantling the central block of a dual-shield TBM according to claim 1, characterized in that, In step S2, lifting lugs are provided on the center block of the cutter head, specifically including: two lifting points, an upper left lifting point and an upper right lifting point, are provided at a position 50 degrees to the left and right directly above the flange, and two lifting points, a lower left lifting point and a lower right lifting point, are provided at a position 50 degrees to the left and right directly below the flange.

4. The method for dismantling the central block of a dual-shield TBM according to claim 3, characterized in that, The turning-over operation in step S5 specifically includes the following steps: S5.1: Use the left and right suspension points on the front shield to connect and tension the upper left and upper right suspension points on the upper part of the center block via an electric hoist, so that the center block is suspended in the air; S5.2: Use the left and right lifting points on the support shield to connect with the lower left and lower right lifting points of the center block via an electric hoist; S5.3: Simultaneously tension the electric hoist on the support shield and simultaneously loosen the electric hoist on the front shield, so that the bottom of the center block is lifted and the whole structure changes from a vertical state to an inclined state. S5.4: When tilting to the bottom, there is enough space for the transport trolley to run, move the transport trolley to below the center block; S5.5: Continue to alternately operate the electric hoists on the front shield and the support shield until the center block is placed completely horizontally on the transport trolley.

5. The method for dismantling the central block of a dual-shield TBM according to claim 1, characterized in that, In step S1, when making partial cuts to the front shield, the cutting position is located above the shield body, and a portion of the flange plate structure is reserved for setting up lifting points during the cutting process.

6. The method for dismantling the central block of a dual-shield TBM according to claim 4, characterized in that, The transport trolley travels on a track laid inside the shield.

7. The method for dismantling the central block of a dual-shield TBM according to claim 5, characterized in that, Throughout the dismantling process, no additional lifting points were set up, and no chamber expansion was carried out. The shield structure of the dual-shield TBM itself was used as the support foundation for all lifting operations.

8. The method for dismantling the central block of a dual-shield TBM according to claim 2, characterized in that, A 30-ton lifting point is set on the left and right sides directly above the annular flange plate of the front shield; a 20-ton lifting point is set on the left and right sides 50 degrees above the annular flange plate at the rear end of the support shield.