Variable-diameter launching method for trolley

Abstract

The invention belongs to the technical field of engineering construction equipment, and discloses a trolley variable-diameter launching method which comprises the following steps: firstly, reducing the width of a trolley from 6m to 4.9 m through a trolley narrowing mechanism so as to transport and hoist in a limited space and complete assembly; when tunneling to 80m, expanding the width of the trolley to 6m, and recovering the bearing capacity of the trolley; continuously tunneling to 110m, hoisting a subsequent trolley, and connecting to form a complete machine; and after the shield body passes through the starting tunnel portal, the diameters of the cutter head, the shield body and the shield tail are synchronously expanded to the size required by construction. According to the method, through the flow design of narrowing transportation, reducing assembly and step-by-step expansion, the problems that a traditional shield tunneling machine cannot be started in a limited space and the construction efficiency is low are solved, and the construction efficiency and feasibility under the complex working condition are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering construction equipment, and in particular to a method for starting a trolley with variable diameter. Background Art

[0002] In urban subway construction, earth pressure balance shield machines (EPBs), due to their adaptability to complex strata and their safety, have become a core piece of equipment for tunnel excavation. However, with the increasing density of urban underground space development, shield machines are often required to operate in space-constrained areas such as underground stations and open-cut sections. Because these areas were originally designed as receiving ends for shield machines, the width and height of the structures often cannot meet the space requirements for parking, transit, and launching large-diameter shield machines. Currently, the most common technical solution for adapting shield machines to space-constrained scenarios is to design the cutterhead and shield in sections and use them in conjunction with a fixed-size main drive system to achieve size reduction in a single direction (e.g., only meeting width reduction requirements). However, this type of modification can only address space limitations of a specific size and requires customized design of adaptable components, making it impossible to form a universal solution. For projects that require the simultaneous launch of multiple (e.g., four) large-diameter shield machines in complex terrain (e.g., open-cut structures on sloped sections with a 10m height difference), existing solutions have significant limitations: fixed-size shields cannot pass through narrow structures, forcing the use of a high-cost split-launch model. This results in low underground space utilization, poor equipment coordination efficiency, and difficulty meeting the high-intensity tunneling requirements of simultaneous multi-machine construction. Summary of the Invention The purpose of the present invention is to provide a method for starting a trolley with variable diameter. This method solves the problem that traditional shield machines cannot start as a whole machine in a limited space and have low construction efficiency through the process design of "narrowing transportation-variable diameter assembly-step-by-step expansion", and improves the efficiency and feasibility of construction under complex working conditions.

[0003] The present invention is achieved through the following technical solutions: A method for starting a trolley with variable diameter includes the following steps: S1. Narrow the shield machine trolley assembly. The trolley narrowing mechanism drives the left and right trolley platforms to slide relative to each other along the narrowing slide bar, reducing the trolley width from 6m to 4.9m. S2. In the reduced diameter state, the retracted trolley, connecting bridge, and shield machine main components are hoisted down into the well in sequence, completing assembly within the confined space. S3. After assembly, no-load commissioning and trial excavation are carried out. When the excavation reaches 80m, the trolley width is expanded to 6m through the trolley narrowing mechanism; S4. Continue excavating to 110 m, hoist the subsequent trolley and connect it to the assembled trolley to form a complete machine; S5. After the shield passes through the starting tunnel, the diameters of the cutterhead, shield body, and shield tail are simultaneously expanded to the required dimensions for construction.

[0004] In this solution, the trolley width is first reduced from 6m to 4.9m through the trolley narrowing mechanism, making it adaptable to the transportation and hoisting requirements of narrow sites, solving the problem that traditional trolleys cannot pass through limited spaces due to their fixed size. Then, the trolley, connecting bridge, and shield machine main components are assembled in the reduced diameter state, avoiding assembly difficulties caused by space limitations. When the excavation reaches 80m, the trolley width is expanded to 6m, restoring its normal load-bearing capacity to meet subsequent construction needs. After excavating for another 110m, the subsequent trolleys are hoisted and connected to form a complete machine state, ensuring the complete performance of the equipment. Finally, after the shield body passes through the starting portal, the diameter of the cutterhead, shield body, and shield tail are simultaneously expanded, giving the shield machine full-scale construction capabilities. This method achieves efficient starting of the shield machine in a limited space through the process design of "narrowing transportation-diameter reduction assembly-step-by-step expansion", which not only ensures the equipment's passability in narrow environments, but also gradually releases construction capacity through staged diameter reduction, significantly improving construction efficiency and feasibility under complex working conditions.

[0005] Furthermore, in the narrowing modification step, the parallelogram connecting rod of the trolley narrowing mechanism is driven by a telescopic cylinder, driving the right platform of the trolley to slide along the narrowing slide rod, and the left platform of the trolley moves in the opposite direction synchronously.

[0006] In this solution, the trolley narrowing mechanism drives the parallelogram connecting rod with the help of a telescopic oil cylinder. By utilizing the motion characteristics of the parallelogram mechanism, the right platform of the trolley slides along the narrowing slide bar while the left platform of the trolley moves in the opposite direction synchronously. This design ensures that the left and right platforms of the trolley remain parallel and move synchronously during the width adjustment process, avoiding deflection or jamming, thereby achieving precise transformation of the trolley width between 4.9m and 6m, which not only ensures that the trolley can pass through the limited space smoothly in the narrowed state, but also ensures the stability of the platform structure after expansion, providing reliable width adjustment guarantee for the starting and subsequent construction of the shield machine in a limited space.

[0007] Furthermore, the hoisting and assembly steps include first hoisting the trolley and connecting bridge in the reduced diameter state, and then hoisting the screw machine, the middle front shield bottom block, the main drive, the left and right blocks of the middle front shield, the top block, the assembler, the shield tail and the cutter disc in sequence, and all components are in the reduced diameter state.

[0008] In this plan, the trolley and connecting bridge in the reduced diameter state are hoisted first, and then the screw machine, the bottom block of the middle front shield, the main drive, the left and right blocks of the middle front shield, the top block, the assembly machine, the shield tail and the cutterhead in the reduced diameter state are hoisted in sequence. This assembly sequence and state design is a targeted arrangement based on the limited space construction conditions. Because each component is in the reduced diameter state, its external dimensions are greatly reduced, allowing it to pass smoothly through the narrow hoisting wellhead and limited working space, avoiding the situation where hoisting is difficult or even impossible due to the oversized components. At the same time, hoisting in this order ensures that the installation position of each component in the limited space is accurate, facilitating subsequent connection and debugging, and ensuring that the shield machine can be assembled efficiently and safely in the limited space.

[0009] Furthermore, in the no-load debugging step, the trolley height is adjusted by the trolley lifting and traveling wheel mechanism, and the lifting cylinder drives the lifting plate to drive the traveling wheel to move up and down. The height adjustment range is 0 to 0.3m. After the debugging is completed, continuous excavation is 80m.

[0010] In this solution, the trolley's lifting and lowering wheel mechanism's lifting cylinder drives the lifting plate, which in turn drives the wheels, achieving height adjustment from 0 to 0.3m. This allows precise adjustment of the trolley's height based on site flatness, track elevation, or the required slope at the tunnel's initial section within a confined space, ensuring the coaxial installation and operational stability of the shield machine components. After commissioning, continuous excavation of 80m was conducted, verifying the performance of the shield machine's various systems in the reduced-diameter state and, through actual excavation, verifying the trolley's height adjustment's adaptability to complex strata, ensuring reliable operation of the equipment through confined spaces.

[0011] Furthermore, in the step of expanding the trolley width, the telescopic oil cylinder supplies oil to the oil rod cavity, pushing the connecting rod to drive the right platform of the trolley to reset, while the left platform of the trolley moves in the opposite direction synchronously.

[0012] In this solution, after the telescopic cylinder supplies oil to the rod chamber, the hydraulic power drives the parallelogram connecting rod mechanism to operate, so that the right platform of the trolley is reset to the initial position along the narrowing slide rod. At the same time, the left platform of the trolley is synchronously moved in the opposite direction by the connecting rod transmission. This design utilizes the equidistant transmission characteristics of the parallelogram connecting rod to ensure that the left and right platforms remain parallel and the displacement is consistent when the width is expanded, avoiding platform tilting or jamming, thereby accurately restoring the trolley width to the standard construction state of 6m, which not only meets the load-bearing requirements of the shield machine after passing through a limited space, but also ensures the stability and reliability of the expansion process through the action of hydraulic drive and connecting rod transmission.

[0013] Furthermore, in the step of hoisting the subsequent trolley, multiple gantry cranes and multiple slag outlets are arranged to enable multiple shield machines to start synchronously, and each shield machine is equipped with two rows of fully staffed battery vehicles.

[0014] In this plan, the layout design of multiple gantry cranes and multiple slag outlets enables the simultaneous launch of multiple shield machines. This layout fully utilizes the site resources within the limited space and significantly improves construction efficiency. Multiple gantry cranes work together to simultaneously hoist the subsequent trolleys of multiple shield machines, eliminating waiting time for equipment hoisting and accelerating construction progress. Multiple slag outlets provide multiple channels for shield machine slag discharge, preventing congestion during the slag discharge process and ensuring construction continuity. Each shield machine is equipped with two fully staffed battery-powered vehicles to promptly transport the slag generated by the shield machine operation and supply the materials required for construction, ensuring the continuous and efficient operation of the shield machine.

[0015] Furthermore, in the step of expanding the diameter of the cutter disc, shield body and shield tail, the cutter disc assembly pushes the movable end of the banner through the spoke telescopic cylinder, so that the panel knife box is separated along the T-shaped slide groove, and the movable wear-resistant ring slides outward synchronously to fill the gap, and the diameter is expanded from 8.2m to 8.6m.

[0016] In this solution, the cutterhead assembly is powered by spoke telescopic cylinders, pushing the movable ends of the spokes along T-shaped slides, driving the panel and cutter box to separate, allowing the cutterhead diameter to expand from 8.2m to 8.6m to accommodate different tunnel construction sections. Simultaneously, the movable wear-resistant ring, driven by the movable ends of the spokes, slides outward synchronously, promptly filling the gap created by the separation of the panel and cutter box. This not only protects the cutterhead edge from soil abrasion, but also ensures that the cutterhead maintains its circular structure and integrity during the diameter change process, preventing soil, sand, and groundwater from infiltrating the cutterhead and affecting equipment operation.

[0017] Furthermore, in the shield body expansion step, the tray telescopic cylinder and the middle shield telescopic cylinder of the front shield telescopic mechanism move synchronously to push the front shield blocks and the middle shield blocks to expand radially, and the compression amount of the polyurethane strip in the U-shaped groove of the socket-type sealing structure is adjusted to 2 to 3 mm.

[0018] In this solution, the tray telescopic cylinder of the front shield telescopic mechanism and the middle shield telescopic cylinder operate synchronously, working together to push the front and middle shield blocks to expand radially, expanding the shield diameter from its initial state to the required size for construction. This matches the change in cutterhead diameter and ensures consistent overall structural dimensions of the shield machine. Simultaneously, the polyurethane strips within the U-grooves of the shield's socket-and-spigot sealing structure are precisely compressed to a value of 2-3mm during block expansion. This compression ensures that the strips tightly fill the gaps between the blocks, forming a reliable waterproof seal that effectively prevents groundwater, soil, and sand from infiltrating the shield. It also prevents excessive compression that could cause the strips to deform and prematurely age, thereby reducing sealing performance.

[0019] Furthermore, in the shield tail expansion step, the shield tail expansion cylinder drives the outer socket structure of the upper half of the shield tail to separate from the inner socket structure of the lower half, and the single-pass brush wire compression amount of the shield tail brush is adjusted to 8-12 mm to form multiple seals.

[0020] In this solution, the shield tail expansion cylinder serves as the power source, driving the separation of the outer socket structure in the upper half of the shield tail from the inner socket structure in the lower half, thereby expanding the shield tail diameter to match the changes in the shield body and cutterhead diameter, ensuring that the overall structure of the shield machine remains consistent and adaptable after the diameter change. At the same time, the compression of the single brush wire of the shield tail is precisely adjusted to 8-12mm. Through reasonable compression control, each brush of the shield tail can not only closely fit the surface of the segment, but also form an effective sealing barrier, preventing groundwater, slurry, and soil and sand from leaking into the shield machine through the gap between the shield tail and the segment.

[0021] Furthermore, it also includes a segment assembly machine replacement step. After the diameter of the shield machine is expanded, the segment assembly machine and crane suction cup are replaced with those that match the expanded diameter, which are used for segment assembly of tunnels with different diameters.

[0022] In this solution, the segment assembly machine replacement step is implemented, replacing the existing segment assembly machine and crane suction cup with a model that matches the expanded diameter. This operation ensures that the segment assembly machine can accurately grasp, locate, and assemble the segments required for the corresponding diameter tunnel, ensuring the precision and sealing of the splicing between the segments. By adapting segment assembly machines of different diameters, the shield machine can still perform segment assembly operations efficiently and stably after the diameter expansion is completed, meeting the construction requirements of tunnels with different cross-sectional sizes.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. This invention overcomes the efficiency bottleneck of traditional single-equipment hoisting and single-channel slag discharge through the coordinated layout of multiple gantry cranes and multiple slag outlets. It enables the simultaneous start-up of multiple shield machines. Combined with the transportation configuration of two fully staffed battery vehicles for each shield machine, this significantly improves the efficiency of slag transportation and the continuity of material supply within a limited space. 2. The present invention adopts a trolley frame telescopic mechanism driven by a hydraulic cylinder, which can accurately adjust the trolley diameter from 6.2m to 8.6m according to tunnel requirements at the initial stage, breaking through the limitation of traditional trolleys with fixed diameters that require secondary disassembly and assembly, shortening the initial preparation time, and avoiding equipment replacement costs caused by changes in tunnel diameter. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings: Figure 1 This is the front view of the cutterhead's variable diameter contraction structure; Figure 2 It is the side view of the extension of the cutter head edge; Figure 3 This is a top view of the cutterhead's variable diameter contraction structure; Figure 4 This is a front view of the cutterhead variable diameter extension structure; Figure 5 This is the front view of the shield's contraction structure; Figure 6 This is a schematic diagram of the shield tail contraction structure; Figure 7 This is the front view of the shield expansion structure; Figure 8 This is a schematic diagram of the shield tail expansion structure; Figure 9 This is a side view of the shield tail movable hinge seat; Figure 10 This is a partial schematic diagram of the shield tail expansion structure; Figure 11 It is the side view of the shield's contraction structure; Figure 12 It is a side view of the shield extension structure; Figure 13 It is a side view of the shield extension mechanism; Figure 14 This is the front view of the shield extension mechanism; Figure 15 Diagram of the relationship between the trolley expansion and the tunnel; Figure 16 It is the side view of the trolley; Figure 17 This is a front view of the trolley extension mechanism; Figure 18 It is a side view of the trolley extension mechanism; Figure 19 This is the structural diagram of the trolley lifting and traveling wheels; Figure 20 This is a schematic diagram of the structure of the trolley after diameter reduction; Figure 21 This is the layout diagram of the four-line shield tunneling start; Figure 22 This is the hydraulic and electrical control diagram for the shield machine and trolley reduction; Figure 23 Schematic diagram of the process of origination; Figure 24 This is a schematic diagram of the process of avoiding gantry cranes and electric vehicles.

[0025] Markings and corresponding parts names in the accompanying drawings: 1-cutter disc spoke telescopic mechanism, 1-1 banner telescopic base, 1-2 banner telescopic cylinder, 1-3 telescopic seal, 1-4 banner movable end, 1-5 banner fixed end shaft, 1-6 movable wear-resistant plate; 2-Panel knife box, 3-Spoke wear ring, 4-Middle support ring; 5- Panel movable wear-resistant ring, 5-1 movable wear-resistant ring, 5-2 fixed wear-resistant ring, 5-3 movable wear-resistant ring hinge end, 5-4 wear-resistant ring alloy, 5-5 panel dividing line, 5-6 limit pin; 6- fixed end of spoke, 7- support bracket of cutter head, 8- movable end on the left side of panel, 9- movable end on the right side of panel, 10- front shield block; 11- front shield telescopic mechanism, 11-1 telescopic pallet fixed hinge, 11-2 pallet fixed seat, 11-3 pallet telescopic cylinder movable hinge, 11-4 pallet telescopic cylinder, 11-5 pallet telescopic cylinder fixed hinge, 11-6 pallet end face; 12-front shield telescopic cylinder, 13-main drive telescopic base, 14-middle shield telescopic base, 15-middle shield telescopic cylinder; 16-articulated movable mechanism, 16-1 articulated fixed seat, 16-2 articulated seal, 16-3 articulated oil cylinder, 16-4 articulated movable seat pin, 16-5 shield tail socket section, 16-7 articulated movable seat, 16-8 shield tail; 17- telescopic mechanism at the bottom of the front shield, 18- telescopic mechanism at the bottom of the middle shield; 19-Shield tail telescopic mechanism, 19-1-Shield tail upper half external socket structure, 19-2-Shield tail lower half internal socket structure, 19-3-Shield tail expansion cylinder, 19-4-Shield tail socket seal, 19-5-Shield tail expansion cylinder support, 19-6-Shield tail brush; 20- shield body upper block, 21- shield body left block, 22- shield body right block, 23- shield body lower block; 24-trolley narrowing mechanism, 24-1-trolley left platform, 24-2-left zoom end surface, 24-3-connecting rod pin seat, 24-4-narrowing slide rod, 24-5-connecting rod, 24-6-connecting rod pin, 24-7-telescopic pull rod, 24-8-cylinder sleeve, 24-9-telescopic cylinder, 24-10-telescopic cylinder support, 24-11-trolley right platform; 25-trolley assembly; 26-Trolley lifting wheel mechanism, 26-1-Trolley base, 26-2-Trolley mechanism rib, 26-3-Cylinder fixing pin, 26-4-Lifting cylinder, 26-5-Hinged plate, 26-6-Hinged plate fixing pin, 26-7-Hinged plate movable pin, 26-8-Lifting plate, 26-9-Trolley axle, 26-10-Trolley, 26-11-Trolley rail; 27-Trolley walkway guardrail, 28-Open cut structure. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0027] Example 1 This embodiment 1 provides an earth pressure balance shield machine suitable for a confined space environment, such as Figure 1-Figure 7 and Figure 15 As shown, it includes a cutter head assembly, a shield body assembly, a shield tail assembly and a trolley assembly; Among them, the above-mentioned cutter disc assembly serves as a dynamic variable diameter and wear-resistant protection system. Its core function is to drive the panel blocks to expand / contract through the spoke telescopic mechanism to achieve diameter adjustment of 8.2m to 8.6m. At the same time, the gap is closed with the help of wear-resistant rings to maintain the sealing of the entire circle structure. It includes multiple groups of cutter disc spoke telescopic mechanisms 1 arranged along the same center of a circle. The two sides of each group of cutter disc spoke telescopic mechanisms 1 respectively drive 1 / 2 of the panel knife box 2 to expand or retract, wherein the adjacent panel knife boxes 2 are overlapping structures in the circumferential direction, and the overlapping surfaces are closed by the panel movable wear-resistant ring 5 to realize an adjustable structure of the entire circle diameter.

[0028] Specifically, see Figures 1-4 As shown, the cutterhead assembly includes 6 sets of cutterhead spoke telescopic mechanisms 1, panel cutter box 2, spoke wear-resistant ring 3, intermediate support ring 4 and panel movable wear-resistant ring 5, which can achieve diameter adjustment of 8.2m~8.6m. Among them, each set of cutterhead spoke telescopic mechanism 1 drives 1 / 2 on both sides respectively. The panel knife box 2, each set of cutter disc spoke telescopic mechanism 1 includes a banner telescopic base 1-1, a banner telescopic oil cylinder 1-2 and a telescopic seal 1-3. The banner telescopic base 1-1 is welded to the edge of the middle support ring 4 of the cutter disc using Q345B steel plate, and a hinge hole is processed on the surface of the base to provide an installation foundation for the entire mechanism. The banner telescopic oil cylinder 1-2 is a double-acting piston cylinder, and its cylinder end is hinged to the banner telescopic base 1-1 through a pin shaft, and the piston rod end is connected to the banner movable end 1-4 through a ball joint. The banner movable end 1-4 can be driven hydraulically to achieve telescopic action, and the telescopic seal 1-3 is a U-shaped polyurethane sealing ring, which is embedded in the annular groove of the banner fixed end 6 and the banner movable end 1-4, and can effectively prevent debris from invading the hydraulic system; Among them, the front end of the banner movable end 1-4 is processed with a T-shaped slide groove for installing the panel knife box 2, and the rear end is slidably matched with the banner fixed end shaft 1-5 through a linear bearing. That is, the banner movable end 1-4 is driven by hydraulic pressure to slide on the banner fixed end shaft 1-5 to achieve telescopic action, and passes through the center of the banner telescopic base 1-1 and is fixed to the banner fixed end 6 through a locking nut. The movable wear-resistant plates 1~6 are cast with ZGMn13 wear-resistant alloy and welded to the outside of the banner movable end 1-4; Among them, the panel knife box 2 and the movable wear-resistant ring 5 constitute a cutting and sealing unit, and the left movable end 8 and the right movable end 9 of the panel are welded with 16Mn steel plates. The adjacent panels are overlapped with a 15° slope, and the adjacent left movable ends 8 and the right movable ends 9 of the panel are overlapped with a 15° slope. They overlap with each other, that is, they are overlapping structures in the circumferential direction, and the overlapping surfaces are closed by the panel movable wear-resistant ring 5. A U-shaped sealing groove is also provided on the overlapping surface, and the inner side of the U-shaped sealing groove is fixed to the flange surface of the movable end 1-4 of the banner. One end of the movable wear-resistant ring 5-1 is hinged to the cutter disc support bracket 7 through a pin shaft and the movable wear-resistant ring hinge end 5-3, and the other end is inserted into the T-shaped slide groove of the movable end 1-4 of the banner through a limit pin 5-6, and the slide groove gap is ≤0.3mm To ensure that no gaps are exposed when the diameter is changed, as the cutter disc spoke telescopic mechanism 1 moves, the movable wear-resistant ring 5-1 can slide outward or retract inward to fill or cover the gap caused by the expansion or contraction of the panel knife box 2, so that the entire circle diameter of the cutter disc can be adjusted.

[0029] At the same time, the fixed wear-resistant ring 5-2 is welded to the edge of the intermediate support ring 4 and overlaps with the movable wear-resistant ring 5-1 by 3mm to form a full-circular protective structure. The wear-resistant ring alloy 5-4 covers the working surface of the movable wear-resistant ring 5-1. The plasma surfacing process is adopted and the wear-resistant life is ≥10,000 rings. The 6 groups of spoke wear-resistant rings 3 are welded to the outside of the movable ends 1-4 of the banner to protect the spoke edges. The intermediate support ring 4 is a ring-shaped steel structure, which is connected to the fixed end 6 of the spoke through 6 cutter head support brackets 7.

[0030] The shield assembly is connected to the rear side of the cutterhead assembly and includes a plurality of blocks. Each block is driven by a corresponding first adjustment assembly to enable the shield assembly and the cutterhead assembly to be expanded or retracted synchronously. Specifically, see Figure 5-Figure 14 As shown, the shield assembly is connected to the rear side of the cutter head assembly and includes multiple blocks, namely the front shield block (10), the upper shield block (20), the left block (21), the right block (22), and the lower block (23). Each block is driven by the corresponding first adjustment assembly. The cylinder end of the tray telescopic oil cylinder (11-4) of the front shield telescopic mechanism (11) is fixed, and the piston rod end is connected to the front shield block (10). One end of the middle shield telescopic oil cylinder (15) is fixed to the middle shield telescopic base (14), and the other end is connected to the middle shield block. When the diameter needs to be changed, the tray telescopic oil cylinder (11-4) and the middle shield telescopic oil cylinder (15) act synchronously to push the front shield block (10) and the middle shield block to expand radially, so that the shield assembly and the cutter head assembly are synchronously expanded or retracted. At the same time, the U-shaped groove of the socket-type sealing structure is set at the block connection. The compression amount of the polyurethane strip in the groove is adjusted to 2-3mm when the block expands, ensuring the sealing of the shield during the diameter change process and preventing groundwater and soil sand from leaking. The shield assembly includes a front shield block 10, an upper shield block 20, a left shield block 21, a right shield block 22, a lower shield block 23 and a first adjustment assembly. The front shield block 10 is located at the front end of the shield assembly and is directly connected to the rear side of the cutter head assembly. A socket flange is provided at the rear end of the front shield block 10. The upper shield block 20, the left shield block 21, the right shield block 22 and the lower shield block 223 are arranged around each other along the axis of the rear side of the front shield block 10 to form an annular cavity and the inner side is provided with a socket flange matching the socket flange. The first adjusting assembly drives the sliding mechanism between the adjacent blocks to move radially, so that the upper shield block 20, the left shield block 21, the right shield block 22 and the lower shield block 22 are synchronously expanded or retracted with the cutter head assembly. Here, the sliding mechanism includes flanges and grooves between adjacent blocks. When the diameter is expanded or reduced, the flanges and grooves on the contact surfaces of the blocks can slide relative to each other in the circumferential direction. In some embodiments, the adjacent blocks can also slide by means of a high T-shaped guide rail in combination with a graphite copper sleeve. In this embodiment, the first adjustment component serves as a hydraulic drive system, including a front shield telescopic mechanism 11 and a middle shield telescopic mechanism; each sliding mechanism is matched and connected with the front shield telescopic mechanism 11 and the middle shield telescopic mechanism, the front shield telescopic mechanism 11 is located at the rear end of the front shield block, and is distributed at 4 locations. The front shield bottom telescopic mechanism 17 in the figure is the state when the front shield telescopic mechanism 11 is installed at the bottom of the front shield, and the middle shield telescopic mechanism is located at the rear end of the middle shield block, and is correspondingly distributed at 4 locations. The middle shield bottom telescopic mechanism 18 in the figure is the state when the middle shield telescopic mechanism is installed at the bottom of the middle shield; the front shield telescopic mechanism 11 includes a tray telescopic oil cylinder 11-4, and the two ends of the tray telescopic oil cylinder 11-4 are fixedly hinged by the telescopic tray 11- The front shield block 10 and the pallet end face 11-6 are connected by a movable hinge 11-3. The pallet mounting base 11-2 is welded to the rear end of the front shield block 10. During expansion, the pallet telescopic cylinder 11-4 pushes the pallet end face 11-6 outward, causing the sliding mechanism to slide circumferentially. The middle shield telescopic mechanism comprises multiple sets of middle shield telescopic cylinders 15, each of which drives a corresponding middle shield block. The barrel ends of the middle shield telescopic cylinders 15 are fixed to the middle shield telescopic base 14. When the diameter needs to be changed, the pallet telescopic cylinders 11-4 and the middle shield telescopic cylinders 15 operate synchronously, pushing the front and middle shield blocks 10 and 11-6 radially, thereby simultaneously expanding or retracting the shield assembly and the cutterhead assembly. Furthermore, a U-shaped groove with a socket-and-spigot sealing structure is provided at the block connection. The polyurethane strip within the groove is compressed by 2-3 mm during block expansion, ensuring the shield's sealing during diameter change and preventing groundwater and soil seepage.

[0031] Among them, the above-mentioned shield tail assembly is connected to the rear side of the shield body assembly through a hinged movable mechanism 16. It includes two parts, an upper part and an lower part. There is a socket structure between the upper part and the lower part. The socket structure is driven by the second adjustment assembly to expand or retract synchronously with the shield body assembly.

[0032] Specifically, see Figures 6-10 As shown, The shield tail assembly is connected to the rear side of the shield body assembly through a hinged movable mechanism (16), and comprises an upper and lower part, which are connected by a shield tail telescopic mechanism 19, wherein the upper part is an outer socket structure 19-1 of the upper half of the shield tail, and the lower part is an inner socket structure 19-2 of the lower half of the shield tail, and a socket structure is formed between the two.

[0033] The articulated movable mechanism 16 is used as a dynamic connection unit. 12 circular arrays are welded to the articulated fixed seat 16-1 at the rear end of the shield body, and each is equipped with a set of articulated oil cylinders 16-3. The cylinder end of the articulated oil cylinder 16-3 is hinged to the articulated fixed seat 16-1 through a pin shaft. The output end of the articulated oil cylinder 16-3 is hinged to the articulated movable seat pin 16-4 through a joint bearing. The articulated movable seat 16-7 is embedded in the shield body slide groove and contacts the guide roller, and a lip-shaped articulated seal 16 is set at the articulated gap. -2, to prevent water and soil intrusion, a hinged movable seat pin 16-4 is inserted into the shield tail socket section 16-5. Driven by an articulated cylinder 16-3, the shield tail can swing relative to the shield body to accommodate curved tunnel construction. A shield tail socket seal 19-4 is connected between the upper shield tail's external socket structure 19-1 and the lower shield tail's internal socket structure 19-2. Multiple shield tail brushes 19-6 are installed on the walls of the cavity formed by these two structures. When the shield body changes diameter, the shield tail expansion cylinder 19-3 drives the upper shield tail's external socket structure 19-1 and the lower shield tail's internal socket structure 19-2 apart, simultaneously adjusting the compression of each brush filament of the shield tail brush 19-6 to 8-12 mm. This creates a multi-layer seal, ensuring a tight seal between the shield tail and the segments and preventing external water and soil intrusion.

[0034] Among them, the above-mentioned trolley assembly is used to carry the earth pressure balance shield machine, which includes a trolley left platform 24-1 and a trolley right platform 24-11. Multiple sets of trolley narrowing mechanisms 24 are arranged between the trolley left platform 24-1 and the trolley right platform 24-11. Under the drive of the trolley narrowing mechanism 24, the trolley left platform 24-1 and the trolley right platform 24-11 can approach or separate from each other.

[0035] Specifically, see Figures 15-20As shown, the four narrowing slide bars 24-4 of the above-mentioned trolley narrowing mechanism 24 are fixed in parallel to the left platform 24-1 and the right platform 24-11 of the trolley, the parallelogram connecting rod 24-5 is hinged on the inner side of the platform through the connecting rod pin seat 24-3, the cylinder end of the telescopic cylinder 24-9 is fixed to the right platform 24-11 of the trolley, and the piston rod end is hinged to the parallelogram connecting rod 24-5; when the telescopic cylinder 24-9 is working, it pushes the parallelogram connecting rod 24-5, driving the right platform 24-11 of the trolley to slide along the narrowing slide bar 24-4, and at the same time the left platform 24-1 of the trolley moves in the opposite direction synchronously, so that the trolley width can be reduced from 6m to 4.9m or expanded from 4.9m to 6m in a limited space, which is convenient for the transportation and assembly of the shield machine in a limited space.

[0036] In addition, the trolley assembly 25 also includes a trolley lifting and running wheel mechanism 26, which moves along the trolley rail 26-11. The trolley lifting and running wheel mechanism 26 includes a trolley base 26-1. The trolley base 26-1 is a steel frame, and a hinged plate fixing pin 26-6 is installed to limit the stroke. The cylinder end of the lifting cylinder 26-4 is hinged to the trolley base 26-1, and the piston rod end is connected to the lifting plate 26-8 through the hinged plate 26-5. The lifting plate 26-8 is embedded in the hinged plate movable pin 26-7 of the trolley base 26-1 and slides. The running wheel shaft 26-9 is fixed to the lifting plate 26-8 through a bearing, and the running wheel 26-10 is connected to the running wheel shaft 26-9. The lifting cylinder 26-4 drives the lifting plate 26-8 to drive the walking wheel 26-10 to rise and fall. The height adjustment range is 0 to 0.3m. The height of the trolley can be adjusted according to the site conditions and construction requirements in the limited space, further enhancing the adaptability of the shield machine in a limited space environment.

[0037] Example 2 This embodiment 2 provides a method for starting a trolley with variable diameter, such as Figure 21-24 As shown, the following steps are included: S1. Narrow the shield machine trolley assembly. The trolley narrowing mechanism drives the left and right trolley platforms to slide relative to each other along the narrowing slide bar, reducing the trolley width from 6m to 4.9m. Specifically, the telescopic cylinder 24-9 of the trolley narrowing mechanism 24 is started, and the cylinder supplies oil to the rodless cavity, pushing the parallelogram connecting rod 24-5 to rotate around the connecting rod pin seat 24-3, driving the trolley right platform 24-11 to slide along the four narrowing slide rods 24-4 toward the trolley left platform 24-1. At the same time, the left platform 24-1 is synchronously moved in the opposite direction by the connecting rod transmission. The hard chrome plating on the surface of the narrowing slide rod 24-4 ensures that the sliding friction coefficient is ≤0.1, and the platform movement speed is controlled within 5mm / s until the width is reduced from 6m to 4.9m. During the narrowing process, the telescopic pull rod 24-7 prevents the platform from being stuck due to overload, and the cylinder sleeve 24-8 protects the piston rod from being bumped. S2. In the reduced diameter state, the retracted trolley, connecting bridge, and shield machine main components are hoisted down into the well in sequence, completing assembly within the confined space. Specifically, multiple gantry cranes coordinated the operation, first hoisting trolleys 1-5 and the connecting bridge, which had been reduced to a diameter of 4.9m, and lowering them underground via the derrick rails. Subsequently, the screw conveyor, the center front shield base block, the main drive, the left and right center front shield sections, the top block, the assembly machine, the shield tail, and the cutterhead were successively hoisted, all in a reduced diameter state (for example, the cutterhead diameter was temporarily maintained at 8.2m). During the hoisting, the lifting cylinder 26-4 of the trolley's lifting wheel mechanism 26 lowered the height of the running wheel 26-10 by 0.15m to accommodate the deviation in the underground rail surface elevation.

[0038] S3. After assembly, no-load commissioning and trial excavation are carried out. When the excavation reaches 80m, the trolley width is expanded to 6m through the trolley narrowing mechanism; Specifically, the trolley lifting wheel mechanism 26 was activated, and the lifting cylinder 26-4 supplied oil to the rodless chamber, pushing the hinged plate 26-5, which in turn caused the lifting plate 26-8 to slide vertically along the hinged plate movable pin 26-7. The height of the running wheel 26-10 was continuously adjusted within a range of 0 to 0.3 meters, and the trolley levelness was calibrated to ±1 mm / m. The cutterhead spoke extension mechanism 1 was debugged, and the spoke extension cylinder 1-2 drove the panel cutter box 2 to perform three reciprocating diameter reduction tests with a diameter of 8.2 to 8.6 meters. The clearance between the limit pin 5-6 of the movable wear ring 5-1 and the T-shaped slideway was ≤0.3 mm.

[0039] S4. Continue excavating to 110 m, hoist the subsequent trolley and connect it to the assembled trolley to form a complete machine; Specifically, when excavation reaches 80 meters, telescopic cylinder 24-9 supplies oil to the rod chamber, retracting the piston rod and pulling parallelogram connecting rod 24-5 in the opposite direction. The right platform 24-11 of the trolley returns along the narrowing slide bar 24-4, and the left platform 24-1 simultaneously moves in the opposite direction until the trolley width is restored to 6 meters. After expansion, the clearance between connecting rod pin 24-6 and the pin seat is ≤0.2mm, ensuring the stability of the platform structure.

[0040] Continue to excavate to 110m, using 4 gantry cranes (such as Figure 21 40, 45, 47, 50) to hoist the subsequent trolleys 6-7, and connect them with the assembled trolley 5 through bolts to form a trolley group with a total length of about 100m. Each shield machine is equipped with 2 full battery cars (such as Figure 21 54, 37), and the slag transportation is realized through 8 slag outlets (such as 38, 44, 46, and 49 on the left line).

[0041] S5. After the shield passes through the starting tunnel, the diameters of the cutterhead, shield, and shield tail are simultaneously expanded to the required dimensions for construction. After the shield passes through the initial tunnel portal, the hydraulic pump station supplies oil to the banner extension cylinder 1-2, pushing the banner's movable end 1-4 radially outward along the T-shaped slot, separating the left and right movable ends 8 and 9 of the panel cutter box 2. The movable wear ring 5-1, guided by the limit pin 5-6, slides outward synchronously, filling the panel gap and expanding the diameter from 8.2m to 8.6m. A tungsten carbide alloy overlay layer on the surface of the movable wear ring 5-1 ensures edge wear resistance during expansion.

[0042] Then, the tray telescopic cylinder 11-4 of the front shield telescopic mechanism 11 and the middle shield telescopic cylinder 15 operate synchronously to push the front shield block 10 and the middle shield block to expand radially. The compression amount of the polyurethane strip in the U-shaped groove of the socket-type sealing structure is adjusted to 2-3 mm to form a waterproof barrier. The four-bar linkage of the main drive telescopic base 13 synchronously compensates for the main drive displacement.

[0043] Finally, the tail expansion cylinder 19-3 separates the upper outer socket structure 19-1 from the lower inner socket structure 19-2. The tail brush 19-6 adjusts the compression of each brush pass to 8-12 mm, creating a multi-layer seal. The articulated cylinder 16-3 of the articulated mechanism 16 simultaneously adjusts the tail's posture to ensure a tight fit with the segment after expansion.

[0044] In this embodiment, after the shield machine's diameter is expanded, the segment assembly machine and crane suction cup are replaced with one matching the expanded diameter to assemble segments for tunnels of different diameters. For the expanded tunnel diameter of 8.6m, the segment assembly machine originally designed for an 8.2m diameter is removed and replaced with one matching the 8.6m diameter. The assembly machine is equipped with a high-precision hydraulic positioning system and a laser guide device to ensure segment assembly accuracy within ±5mm. The crane suction cup uses an electromagnetic structure with a suction force of ≥1.5 times the segment weight, ensuring safe lifting.

[0045] It should be noted that, in the attached drawings, serial numbers 11.1, 14.1, 17.1, and 18.1 respectively represent the states of serial numbers 11, 14, 17, and 18 when the shield body is expanded; serial number 19 represents the state of the shield tail when it is contracted, and serial number 19.1 represents the state of the shield tail when it is expanded; and serial numbers 20.1, 21.1, 22.1, and 23.1 respectively represent the states of serial numbers 20, 21, 22, and 23 when the upper, left, right, and lower blocks of the shield body are expanded.

[0046] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for starting a trolley with variable diameter, characterized in that: The steps include: S1. Narrowing the shield machine trolley assembly, driving the trolley left platform (24-1) and the trolley right platform (24-11) to slide relative to each other along the narrowing slide bar (24-4) through the trolley narrowing mechanism (24), thereby reducing the trolley width from 6m to 4.9m; S2. In the reduced diameter state, the retracted trolley, connecting bridge, and shield machine main components are hoisted down into the well in sequence, completing assembly within the confined space. S3. After assembly, no-load commissioning and trial excavation are carried out. When the excavation reaches 80m, the trolley width is expanded to 6m through the trolley narrowing mechanism (24); S4. Continue excavating to 110 m, hoist the subsequent trolley and connect it to the assembled trolley to form a complete machine; S5. After the shield passes through the starting tunnel, the diameters of the cutterhead, shield body, and shield tail are simultaneously expanded to the required dimensions for construction.

2. A method for starting a trolley with variable diameter according to claim 1, characterized in that: In the narrowing modification step, the parallelogram connecting rod (24-5) of the trolley narrowing mechanism (24) is driven by a telescopic oil cylinder (24-9), driving the trolley right platform (24-11) to slide along the narrowing slide bar (24-4), and the trolley left platform (24-1) moves synchronously in the opposite direction.

3. A method for starting a trolley with variable diameter according to claim 2, characterized in that: The hoisting and assembly steps include first hoisting the trolley and connecting bridge in a reduced diameter state, and then hoisting the screw machine, the middle front shield bottom block, the main drive, the left and right blocks of the middle front shield, the top block, the assembler, the shield tail and the cutter disc in sequence, and all components are in a reduced diameter state.

4. A method for starting a trolley with variable diameter according to claim 3, characterized in that: In the no-load debugging step, the trolley height is adjusted by the trolley lifting and running wheel mechanism (26), and the lifting cylinder (26-4) drives the lifting plate (26-8) to drive the running wheel (26-10) to move up and down. The height adjustment range is 0 to 0.3 m. After the debugging is completed, continuous excavation is 80 m.

5. A method for starting a trolley with variable diameter according to claim 4, characterized in that: In the step of expanding the trolley width, the telescopic oil cylinder (24-9) supplies oil to the oil rod chamber, pushing the connecting rod (24-5) to drive the trolley right platform (24-11) to reset, while the trolley left platform (24-1) moves synchronously in the opposite direction.

6. A method for starting a trolley with variable diameter according to claim 5, characterized in that: In the step of hoisting the subsequent trolley, multiple gantry cranes and multiple slag outlets are arranged to enable multiple shield machines to start synchronously, and each shield machine is equipped with two rows of fully staffed battery cars.

7. A method for starting a trolley with variable diameter according to claim 6, characterized in that: In the step of expanding the diameter of the cutter disc, shield body and shield tail, the cutter disc assembly pushes the movable end (1-4) of the strip through the spoke telescopic cylinder (1-2), so that the panel cutter box (2) is separated along the T-shaped slide groove, and the movable wear-resistant ring (5-1) slides outward synchronously to fill the gap, and the diameter is expanded from 8.2m to 8.6m.

8. A method for starting a trolley with variable diameter according to claim 7, characterized in that: In the shield body expansion step, the tray telescopic oil cylinder (11-4) of the front shield telescopic mechanism (11) and the middle shield telescopic oil cylinder (15) operate synchronously to push the front shield block (10) and the middle shield block to expand radially, and the compression amount of the polyurethane rubber strip in the U-shaped groove of the socket-type sealing structure is adjusted to 2 to 3 mm.

9. A method for starting a trolley with variable diameter according to claim 8, characterized in that: In the shield tail expansion step, the shield tail expansion cylinder (19-3) drives the outer socket structure (19-1) of the upper half of the shield tail to separate from the inner socket structure (19-2) of the lower half, and the single-pass brush wire compression amount of the shield tail brush (19-6) is adjusted to 8 to 12 mm, forming multiple seals.

10. A method for starting a trolley with variable diameter according to claim 9, characterized in that: It also includes the step of replacing the segment assembly machine. After the diameter of the shield machine is expanded, the segment assembly machine and crane suction cup are replaced to match the expanded diameter, which are used for segment assembly of tunnels with different diameters.

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