Annular tooling and method for deformation correction of tail shield of large-diameter shield machine in highly permeable sand layer

Abstract

The present invention discloses a circular annular tooling and method for correcting deformation of a tail shield of a large-diameter shield machine in a highly permeable sand layer, comprising: a reaction force support frame, which is a circular annular structure, wherein the outer arc surface of the reaction force support frame is provided with first piers at intervals in the longitudinal and circumferential directions, a pre-tightening jack is provided between the first piers in the longitudinal direction of the reaction force support frame, and a plurality of correction jacks are provided in the deformation area of ​​the tail shield corresponding to the outer arc surface of the reaction force support frame; a pad is filled in the gap between the first pier and the tail shield; and a meniscus structure is installed on the inner arc surface of the reaction force support frame corresponding to the deformation area of ​​the tail shield. The present invention solves the deformation of the tail shield of the shield machine and the correction of the full circle of the tail shield.

Description

Technical Field

[0001] The present invention relates to the field of shield tunnel construction, and more specifically, to a circular ring-shaped tool and method for correcting deformation of a tail shield of a large-diameter shield in a highly permeable sand layer. Background Art

[0002] Shield construction has become an important part of tunnel construction, and more and more shield machines are being put into tunnel construction. With the increase in shield projects, more and more problems are encountered when shield machines are excavating in different strata. When the shield machine is excavating in a water-rich and dense sand layer, the strata are dense, and a large foundation reaction force and passive earth pressure will be generated during the shield correction process. When the passive earth pressure on the tail shield is greater than the strength of its own steel plate, the tail shield will produce plastic deformation, resulting in contact and extrusion of the tail shield steel plate, the thrust cylinder support shoe and the pipe segment, and the shield machine is trapped and unable to continue excavation. When encountering such shield excavation problems, it is necessary to use a correction device to correct the deformation of the tail shield so that the shield machine can get out of trouble and continue excavation. Summary of the invention

[0003] The purpose of the present invention is to provide a circular ring-shaped tooling and method for correcting deformation of a large-diameter shield tail shield in a highly permeable sand layer, so as to solve the deformation of the shield machine tail shield and the correction of the full circle of the tail shield.

[0004] In order to achieve these purposes and other advantages according to the present invention, a circular annular tooling for deformation correction of a tail shield of a large-diameter shield machine in a highly permeable sand layer is provided, comprising:

[0005] The reaction support frame is a circular ring structure, the outer arc surface of the reaction support frame is provided with first piers at intervals in the longitudinal direction and the circumferential direction, pre-tightening jacks are provided between the first piers in the longitudinal direction of the reaction support frame, and a plurality of correction jacks are provided in the deformation area of ​​the tail shield corresponding to the outer arc surface of the reaction support frame;

[0006] A pad, which fills the gap between the first buttress and the tail shield;

[0007] The meniscus structure is installed on the inner arc surface of the reaction force support frame corresponding to the deformation area of ​​the tail shield.

[0008] Preferably, the reaction force support frame is composed of a plurality of blocks.

[0009] Preferably, the blocks are fixed by external flanges or by welding.

[0010] Preferably, the cross-sections of the reaction support frame and the meniscus structure are both box structures with double rectangular cross-sections;

[0011] At least two transverse partitions are arranged inside the box structure of the reaction force support frame, and a plurality of first ribs are arranged around the transverse partitions and the box structure of the reaction force support frame;

[0012] A plurality of second ribs are arranged around the inner periphery of the box structure of the meniscus structure.

[0013] Preferably, it also includes:

[0014] A track extending in the longitudinal direction and located below the reaction support frame for sliding the reaction support frame, wherein oblique supports are arranged on both sides of the track and are reinforced by the oblique supports and the tail shield;

[0015] A second pier is used to support the track.

[0016] The present invention also provides a method for correcting deformation of a large-diameter shield tail shield in a highly permeable sand layer using a circular tool, comprising the following steps:

[0017] S1. Determine the deformation of the tail shield;

[0018] S2, installation of reaction support frame, pier and jack;

[0019] S21. According to the load capacity of the segment assembly machine and the rationality of the assembly space of the reaction support frame, the reaction support frame is divided into several blocks. A group of first piers is installed on the outer arc surface of the block in the gap between every 1 to 5 groups of thrust cylinders. The first pier in each group of first piers is arranged along the longitudinal direction of the shield machine, and pre-tightening jacks are placed between the first piers; several correction jacks are installed on the outer arc surface of the block corresponding to the local deformation area of ​​the shield tail steel plate, and pads of different thicknesses are prepared for filling between the first pier and the tail shield;

[0020] S22, when assembling the reaction support frame, the assembling machine uses the tooling arc plate to grab the block and rotate it to the top of the assembling machine, and fix the first pier and the pre-tightening jack between the first piers to the outer arc surface of the block; the first pier and the pre-tightening jack are respectively fixed to the outer arc surface of the block;

[0021] S23, rotating the blocks to the top of the assembly machine, using a hand chain hoist to place the correction jack on the outer arc surface of the reaction support frame, fixing the correction jack to the flat flange of the outer arc surface of the reaction support frame, and then rotating the assembly machine to the assembly area of ​​the reaction support frame to install the blocks;

[0022] S3, the reaction support frame is assembled in blocks;

[0023] S31, the blocks of the reaction support frame are assembled symmetrically from the bottom, and finally the top block is inserted;

[0024] S4, meniscus structure installation;

[0025] The meniscus structure is symmetrically divided into blocks, which are transported to the trolley by a capacitor car, and the vacuum suction cup is removed. The trolley is lifted to the sheet feeder and transported to the bottom of the ring beam. At this time, the segment assembly machine is used to install the tooling cantilever, and the ring beam and tail shield welding hook hanging hoist is used to turn over and install them in place. According to the deformation position, the meniscus is installed to the corresponding deformation position. If there are multiple deformation positions, the meniscus combined with the correction jack can form a full circle correction.

[0026] S5, graded pressurization

[0027] After the whole circle of reaction force support frame is pre-tightened, the hydraulic pump station is activated to synchronously pressurize several correction jacks in stages. After each stage of pressurization reaches the set pressure, the pressure is stabilized for about 15 to 30 minutes. The deformation monitoring of the tail shield weld and deformation part and the stress monitoring of the circular reaction force support frame are carried out. At the same time, it is observed whether there are abnormal displacements in each structure. If there is no abnormality, the next stage of pressure is pressurized as required;

[0028] S6, push correction

[0029] The thrust correction target is set to a shield tail clearance of no less than 4 cm at the maximum deformation point. During the correction, intermittent sand removal and decompression are performed.

[0030] During the process of the correction jack pushing, the concave and deformed tail shield steel plate develops outwards, and pads of different thicknesses need to be gradually inserted. At the same time, the convex tail shield steel plate around it will shrink. At this time, the pads of the corresponding piers need to be gradually removed to achieve the effect of correcting the tail shield as a whole.

[0031] When the pushing deformation reaches 40-70% of the expected requirement, the pressure gradient should be slowed down and multiple pushing corrections should be carried out. When the accumulated residual deformation reaches the expected requirement, the correction work at this position should be stopped and the reaction support frame should be moved to the next position for correction.

[0032] S7, reaction support frame movement

[0033] Retract the correction jack, push the ring longitudinally, and move the reaction support frame forward and backward along the track to correct the uncorrected positions. When the accumulated residual deformation of the uncorrected position reaches the tail shield roundness standard, stop the correction work at that position;

[0034] S8, multiple rounds of correction

[0035] When the circular tooling is fixed in position, the maximum deformation area is constantly changing by performing support correction operations and monitoring the roundness of the tail shield steel plate at or near the position of the maximum deformation area. The position of the meniscus is adjusted to continuously correct the deformation area, thereby achieving 360° correction operations of the circular tooling; the circular tooling moves from the near-center shield to the tail shield, and continuously corrects until the entire range of the tail shield is covered, which is one round of correction; the circular tooling continues to be moved to the near-center shield position, the deformation of the tail shield is monitored, and corrections are continued for multiple times until multiple rounds are completed and the roundness of the tail shield is close to the installed state.

[0036] Preferably, S1 is specifically as follows: during the continuous excavation of the shield machine, the tail shield gap of each ring segment is measured and collected, and the gap between the cylinder support shoe and the tail shield steel plate is periodically observed. If these two gaps exceed the standard or are abnormal, the surveyor should use a total station to measure the roundness of the tail shield. If conditions permit, the ring segment with the abnormal gap should be removed, and a larger space should be reserved longitudinally for the tail shield to measure as many cross sections as possible.

[0037] Preferably, intermittent sand discharge and pressure relief are specifically as follows: a pressure relief hole is opened below the area of ​​large deformation of the shield tail, and the pressure relief hole is opened to release sand before or during the jacking correction, and the pressure relief hole avoids the jacking correction area, the shield tail pipeline and the location of the first pier. After the tail shield correction construction is completed, the tail shield opening needs to be sealed.

[0038] Preferably, S21 also includes setting a track at the bottom of the reaction support frame, and lining the bottom of the track with a second pier, the track serving as a moving path for the reaction support frame, and a plurality of second piers extending from the front end of the reaction support frame to the front end of the current segment are arranged at intervals, and oblique supports are arranged on both sides of the track and reinforced by welding with the tail shield; after the installation of the second pier and the track is completed, the height is measured and verified and fitted so that the height of the reaction support frame meets the requirements when it falls on the first pier and the track, and the lower part of the pad track is adjusted to be radially consistent if necessary.

[0039] Preferably, the S31 is specifically as follows: after the bottom block of the reaction support frame is installed and positioned and consolidated, the adjacent blocks on both sides are installed and crossed in sequence; each block is assembled, the block bolts are installed and tightened, and then spot welded and fixed; after the whole ring reaction support frame is assembled, the pre-tightening jacks embedded between the first piers are used to load evenly, the bolts between the blocks are tightened again, and the longitudinal seams of the reaction support frame blocks are welded and fixed; when installing the blocks above the center line, the auxiliary tooling 7-shaped hooks need to be supplemented with welding on the tail shield to temporarily hang the upper blocks, and the segment assembly machine shall not be moved before the 7-shaped hooks are welded;

[0040] The suction of a single block includes: before the vacuum suction cup sucks the curved steel plate, it is first fixed on the vacuum suction cup through a positioning pin, a sealing gasket is installed between the positioning pin and the curved steel plate for sealing, and then the vacuum pump is turned on to suck the curved steel plate tightly, and the positioning pin is tightened at the same time;

[0041] After the assembling machine sucks up the curved steel plate, a number of screw rods are welded on the outer curved surface of the curved steel plate and fixed one by one with the outer flange of the reaction support frame.

[0042] The present invention includes at least the following beneficial effects: the present invention adopts annular tooling in combination with auxiliary measures such as opening holes and releasing sand to achieve deformation correction and rounding of the tail shield, which can ensure a gap between the tail shield steel plate and the cylinder support shoe and the formed pipe segment, thereby enabling the shield machine to escape from trouble.

[0043] Specifically:

[0044] (1) The circular tooling adopts a block design, which can be positioned in blocks by an assembly machine to achieve full circle assembly. The circular tooling is also dismantled in blocks by a pipe segment assembly machine to improve work efficiency.

[0045] (2) The circular tooling is made of Q460 steel with high structural strength. The structural form is a hollow stiffening rib plate to reduce the weight of the circular tooling. The circular reaction force support frame area at the position to be corrected is equipped with a correction jack and a meniscus structure. The meniscus structure provides rigidity reinforcement for bearing the reaction force of the correction jack.

[0046] (3) The first pier and pre-tightening jack are set between the circular tooling and the tail shield steel plate to play the role of fixing, pre-tightening and eliminating assembly stress.

[0047] (4) The meniscus structure on the circular tooling can be disassembled and assembled to achieve full-circle 360° tail shield deformation correction.

[0048] (5) A track is installed at the bottom of the circular tooling to enable the tooling to move forward and backward and correct the front and rear deformation of the tail shield.

[0049] (6) Use holes in the tail shield to release sand and reduce pressure, thereby reducing the soil pressure behind the deformed tail shield and making room for the jack to push and correct.

[0050] (7) Use the total station and tail shield end face marking to measure the roundness of the tail shield and verify the correction effect of the tail shield.

[0051] (8) Install stress and strain monitoring devices near the deformation of the tail shield and on the circular tooling to monitor the stress and strain during the correction process and ensure construction safety.

[0052] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1a A top view of the annular tooling of the present invention;

[0054] Figure 1b The circular tooling BB of the present invention;

[0055] Figure 1c It is a side view of the circular tooling of the present invention;

[0056] Figure 2 It is a detailed view of the circular annular tooling steel buttress of the present invention;

[0057] Figure 3 It is the overall design drawing of the circular tooling of the present invention;

[0058] Figure 4a It is the design drawing of the circular ring-shaped tooling diaphragm of the present invention;

[0059] Figure 4b This is a design drawing of the first rib of the circular tooling of the present invention;

[0060] Figure 5a It is a cross-sectional view of the connection of the circular tooling blocks of the present invention;

[0061] Figure 5b It is a side view of the connection of the circular tooling blocks of the present invention;

[0062] Figure 6 This is a diagram of the arrangement of opening holes and releasing sand to reduce pressure at the deformation of the tail shield of the present invention;

[0063] Figure 7 It is a detailed diagram of the installation of the first buttress of the circular annular tooling of the present invention;

[0064] Figure 8 It is a layout diagram of the bottom slide rail of the circular tooling of the present invention;

[0065] Fig. 9 This is a detailed diagram of the installation of the circular tooling blocks of the present invention.

[0066] Among them, 1. circular tooling, 2. shield machine wall, 3. reaction support frame, 4. external flange, 5. correction jack, 6. preload jack, 7. first pier, 8. pad, 9. meniscus structure, 10. diaphragm, 11. thrust cylinder, 12. first rib, 13. bolt, 14. bolt connecting plate, 15. stiffening plate, 16. tail shield deformation area, 17. 1# pressure relief hole, 18. 2# pressure relief hole, 19. 3# pressure relief hole, 20. track, 21. second pier, 22. vacuum suction cup, 23. arc steel plate, 24. positioning pin, 25. sealing gasket. DETAILED DESCRIPTION

[0067] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0068] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0069] Example 1

[0070] A circular tool 1 for correcting deformation of a tail shield of a large-diameter shield machine in a highly permeable sand layer, comprising:

[0071] The reaction support frame 3 is a circular ring structure. The outer arc surface of the reaction support frame 3 is provided with first piers 7 at intervals in the longitudinal and circumferential directions. A preload jack 6 is provided between the first piers 7 in the longitudinal direction of the reaction support frame 3. A plurality of correction jacks 5 are provided in the tail shield deformation area 16 corresponding to the outer arc surface of the reaction support frame 3. No pad is provided here, and the jack cylinder area is used as the jacking correction surface. If the effect is not good, it can be considered to add a top iron or an arc steel plate to change the jacking correction area to increase the effect.

[0072] A pad 8, which fills the gap between the first buttress 7 and the tail shield;

[0073] The meniscus structure 9 is installed on the inner arc surface of the reaction force support frame 3 corresponding to the tail shield deformation area 16 .

[0074] In the above technical solution, a circular reaction support frame 3 is designed, and the pre-tightening jack 6 on the outer arc surface of the reaction support frame 3 is used to push the local deformation area of ​​the shield machine wall 2 to correct the deformation of the tail shield. A meniscus tooling is set in the local correction jack 5 area to strengthen the strength and rigidity of the circular support frame. In order to position and fix the reaction support frame 3, the first pier 7 and the pre-tightening jack 6 are set in the non-correction area between the outer arc surface of the reaction support frame 3 and the inner arc surface of the tail shield, corresponding to the position between every two groups of thrust cylinders 11 of the shield machine, such as Figure 1a to 1c In this embodiment 1, the first buttress 7 is shown in detail as follows: Figure 2 As shown, 2 steel piers are set at each point, for a total of 16 steel piers; pre-tightening jacks 6 are set in the remaining non-correction areas, and the pre-tightening jacks 6 use 60t hydraulic jacks to tighten and fix the reaction support frame 3; 6 correction jacks 5 are set in the deformation correction area, and the correction jacks 5 are 320t hydraulic jacks. The design diagram of the overall reaction support frame 3 is shown in Figure 3 shown.

[0075] Furthermore, the reaction support frame 3 is composed of a plurality of blocks, and the reaction support frame 3 is reasonably divided into blocks according to the load capacity of the segment assembly machine and the space for assembling the reaction support frame 3. In the present embodiment 1, in order to facilitate on-site installation and match the working load capacity of the vacuum suction cup 22 of the shield machine segment assembly machine, the reaction support frame 3 is divided into 8 blocks. The smallest block corresponds to a central angle of 17°. All blocks should avoid the cross partition 10 of the reaction support frame 3 and the hydraulic jacks (pre-tightening jacks 6 and correction jacks 5) and the first pier 7. The blocks are connected in the form of an external flange 4 and then spot welded. The specific block angles and block methods have the following effects: Figure 1b As shown, the cross-section and side design of the block connection are as follows Figure 5a-5b shown.

[0076] Furthermore, the blocks are fixed or welded by the outer flange 4. In order to facilitate on-site installation, the working load capacity of the vacuum suction cup 22 of the shield machine segment assembly machine is matched.

[0077] Furthermore, the cross-sections of the reaction support frame 3 and the meniscus structure 9 are both box structures with double rectangular cross-sections;

[0078] At least two transverse partitions 10 are arranged inside the box structure of the reaction force support frame 3, and a plurality of first ribs 12 are arranged around the transverse partitions 10 and the box structure of the reaction force support frame 3;

[0079] A plurality of second ribs are arranged around the inner periphery of the box structure of the meniscus structure 9 .

[0080] In this embodiment 1, the reaction support frame 3 has an inner diameter (radius) of 4650mm, an outer diameter (radius) of 5350mm, and a box structure with a double rectangular cross section. The reaction support frame 3 needs to be provided with a diaphragm 10 to ensure structural rigidity. Two diaphragms 10 are provided at the positions corresponding to the positions between each group of thrust cylinders 11 of the shield machine, which are also the positions of the first pier 7 and the preload jack 6 on the outside of the reaction support frame 3. In order to ensure the strength and rigidity of the preload jack 6 and the first pier 7, eight first ribs 12 are designed between the diaphragms 10. The specific dimensions and structural forms of the diaphragms 10 and the first ribs 12 are as follows: Figure 4a-4b shown.

[0081] In this embodiment 1, a meniscus structure 9 is provided for the correction area of ​​the reaction support frame 3 to strengthen the rigidity of the reaction support frame 3 in the correction area. The cross section of the meniscus structure 9 is a box structure with a double rectangular cross section. A diaphragm 10 of the same form as the reaction support frame 3 is provided inside the meniscus structure 9 at the position corresponding to the correction jack 5, and the second rib plate on the diaphragm 10 is also consistent with the first rib plate 12 of the reaction support frame 3. Form and detailed structure of the meniscus structure 9.

[0082] Furthermore, it also includes:

[0083] A track 20 extending in the longitudinal direction and located below the reaction support frame 3 for sliding the reaction support frame 3. Oblique supports are provided on both sides of the track 20 and are reinforced by the oblique supports and the tail shield;

[0084] The second pier 21 is used to support the track 20 .

[0085] Example 2

[0086] The method for correcting deformation of the tail shield of a large-diameter shield machine in a highly permeable sand layer using the annular tooling 1 in Example 1 comprises the following steps:

[0087] S1. Determine the deformation of the tail shield

[0088] Specifically: During the continuous excavation of the shield, the gap between the tail shield of each ring of segments is measured and collected, and the gap between the propulsion cylinder 11 support shoe and the tail shield steel plate is periodically observed. If these two gaps exceed the standard or are abnormal, the surveyor should use a total station to measure the roundness of the tail shield. If conditions permit, the ring segment with abnormal gap should be removed, and a larger space should be reserved longitudinally for the tail shield to measure as many cross sections as possible. In this embodiment, there is a longitudinal measuring line between each of the 23 groups of cylinders of the shield machine, and the measuring lines of the deformation range of the tail shield are encrypted, with a total of 33 measuring lines, 6 points on each measuring line, and a total of 6 sections. The measuring line position is calculated from the middle and tail shield welds, and the distances are: 0.1m, 0.4m, 0.7m, 1.1m, 1.6m, and 1.9m respectively. The surveyor obtains the roundness of the tail shield of different sections based on the measuring points, and accurately determines the deformation position and deformation value of the tail shield.

[0089] S2, reaction support frame 3, pier and jack installation.

[0090] S21. In the second embodiment, the reaction support frame 3 is divided into 8 blocks with a ring width of 1.2 meters. A group of first piers 7 are installed on the outer arc surface of the block in the gap between every two groups of propulsion cylinders 11. The first pier 7 in each group of first piers 7 is arranged along the longitudinal direction of the shield machine, and pre-tightening jacks 6 (60t jacks) are placed between the first piers 7 to eliminate the stress of the reaction support frame 3 after the full circle assembly; 6 correction jacks 5 (320t hydraulic jacks) are installed on the outer arc surface of the block corresponding to the local deformation area of ​​the shield tail steel plate, and pads 8 of different thicknesses are prepared for filling between the first pier 7 and the tail shield. The specific structural form is as follows: Figure 7 shown.

[0091] According to the on-site construction requirements, a track 20 is set at the bottom of the reaction support frame 3, and a second pier 21 is padded under the track 20. The track 20 serves as the moving path of the reaction support frame 3. A plurality of second piers 21 are arranged at intervals extending from the front end of the reaction support frame 3 to the front end of the current segment, with a spacing of 40 cm. Oblique supports are set on both sides of the track 20 and welded to the tail shield for reinforcement. Figure 8 After the second pier 21 and the track 20 are installed, the heights are measured and checked and fitted so that the height of the reaction support frame 3 when it falls on the first pier 7 and the track 20 meets the requirements, and if necessary, the lower part of the support track 20 is adjusted to be consistent in radial direction.

[0092] S22, when the reaction support frame 3 is assembled, the assembling machine uses the tooling arc plate to grab the block and rotate it to the top of the assembling machine. The first pier 7 and the pre-tightening jack 6 between the first pier 7 are fixed to the outer arc surface of the block using the ear plate welded on the upper part of the tail shield and the hand chain hoist. The first pier 7 and the pre-tightening jack 6 are respectively welded and fixed to the outer arc surface of the block using triangular steel plates to ensure that the first pier 7 and the pre-tightening jack 6 will not fall off during the assembly and correction of the blocks.

[0093] S23, rotate the blocks to the top of the assembly machine, use the hand winch to place the correction jack 5 on the outer arc surface of the reaction support frame 3, fix the correction jack 5 to the flat flange of the outer arc surface of the reaction support frame 3, and then rotate the assembly machine to the assembly area of ​​the reaction support frame 3 to install the blocks.

[0094] S3, the reaction support frame is assembled in 3 parts;

[0095] S31. The blocks of the reaction support frame 3 are assembled symmetrically from the bottom, and the top block is inserted at last. Specifically, after the bottom blocks of the reaction support frame 3 are installed, positioned and consolidated, the adjacent blocks on both sides are installed and crossed in sequence. Each time a block is assembled, the block bolts 13 are installed on the bolt connection plate 14 and fastened and then spot welded to fix. The bolt connection plate 14 is provided with a stiffening plate 15. After the whole ring reaction support frame 3 is assembled, the pre-tightening jacks 6 embedded in the first pier 7 are used for uniform loading to eliminate the adverse stress between the reaction support frames 3. The bolts 13 between the blocks are fastened again and the longitudinal seams of the reaction support frame 3 are welded and fixed. When installing the blocks above the center line, the auxiliary tooling 7-shaped hook needs to be supplemented with welding on the tail shield to temporarily hang the upper block. The segment assembly machine shall not be moved before the 7-shaped hook is welded.

[0096] The suction of a single block includes: before the vacuum suction cup 22 sucks the curved steel plate 23, it is first fixed on the vacuum suction cup 22 by the positioning pin 24, and a sealing gasket 25 is installed between the positioning pin 24 and the curved steel plate 23 for sealing, and then the vacuum pump is turned on to suck the curved steel plate 23 tightly, and the positioning pin 24 is tightened at the same time to prevent the curved steel plate 23 and the vacuum suction cup 22 from slipping and falling off during the grabbing of the reaction force support frame 3. The specific structural form is as follows Fig. 9 shown.

[0097] In this embodiment, the arc-curved steel plate 23 is a t=20mm steel plate with an arc length of 3m, a width of 1.8m and an inner diameter of 10.8m. After the arc-curved steel plate 23 is sucked up by the assembling machine, a number of screws with a diameter of 30mm are welded on the outer arc surface of the arc-curved steel plate 23, and fixed one by one with the outer flange 4 of the reaction support frame 3. The screws can be plug-welded by perforation, and the inner arc surface of the arc-curved steel plate 23 is polished to prevent damage to the vacuum suction cup 22.

[0098] S4, meniscus structure 9 installation;

[0099] The meniscus structure 9 is symmetrically divided into blocks, transported to the trolley by a capacitor car, the vacuum suction cup 22 is removed, the trolley is lifted to the sheet feeding machine, and then transported to the bottom of the ring beam; at this time, the cantilever of the tooling is installed by the pipe segment assembly machine, and the ring beam and the tail shield are welded by hooks and hanging hoists to turn over and install them in place; according to the deformation position, the meniscus is installed to the corresponding deformation position. If there are multiple deformation positions, the meniscus combined with the correction jack 5 can form a full circle correction;

[0100] S5, graded pressurization

[0101] After the whole circle of reaction support frame 3 is pre-tightened, ensure that the flanges of the six correction jacks 5 are firmly fixed. At the same time, the correction jacks 5 are bound and fixed as necessary, and then the hydraulic pump station is activated to synchronously and graded pressurize the six correction jacks 5. The pressurization gradient is temporarily set to 5MPa. After each level of pressurization reaches the set pressure, the pressure is stabilized for about 15 to 30 minutes. The deformation monitoring of the tail shield weld and the deformation part and the stress monitoring of the circular reaction support frame 3 are carried out. At the same time, observe whether there is abnormal displacement of each structure. If there is no abnormality, the next level of pressure is pressurized as required. The graded pressurization table 1 is as follows.

[0102] Table 1 Tail shield correction graded pressure table

[0103] Serial number Pressure MPa Voltage stabilization time min Single jacking force t Six jacking t 1 10 15～30 50 300 2 15 15～30 75 450 3 20 15～30 100 600 4 25 15～30 125 750 5 30 15～30 150 900 6 35 15～30 175 1050 7 40 15～30 200 1200 8 45 15～30 225 1350 9 50 15～30 250 1500 10 55 15～30 275 1650 11 60 15～30 300 1800

[0104] S6, push correction

[0105] In order to achieve the smooth escape of the inner pipe segment of the tail shield from the tail shield, the contact between the outer wall of the pipe edge at the deformation and the guide strip of the inner support shoe of the tail shield is eliminated, and a certain margin is left. The thrust correction target is set to a gap of not less than 4cm between the tail shield and the maximum deformation. Before correction, intermittent sand discharge is performed to reduce pressure. In this embodiment 2, the 1# pressure relief hole 17 is the first pressure relief hole determined, and the drilling position is in the lower area of ​​the 19th oil cylinder (below the position with larger deformation). The specific position and size are as follows: Figure 6 After the pressure relief holes are opened, the sand is released before the circular tooling 1 is corrected. After the sand is released, the jacking correction work begins. The 2# pressure relief holes 18 and 3# pressure relief holes 19 are used as backup opening locations when the effect is not good. The opening locations should avoid the jacking correction area, the tail shield pipeline and the location of the first pier 7 as much as possible. The opening layout is as follows: Figure 6 After the tail shield correction construction is completed, the tail shield opening needs to be sealed to facilitate subsequent normal excavation.

[0106] The intermittent sand discharge and pressure relief are specifically as follows: a pressure relief hole is opened below the area with large deformation of the shield tail, and the pressure relief hole is opened to release sand before the jacking correction. The pressure relief hole avoids the jacking correction area, the shield tail pipeline and the location of the first pier 7. After the tail shield correction construction is completed, the tail shield opening needs to be sealed.

[0107] According to the graded pressure table, the concave deformed shield steel plate is pushed and corrected by a 320t hydraulic jack. During the round correction process, the circumference of the tail shield remains basically unchanged. During the 320t jack pushing process, the concave deformed tail shield steel plate develops outward, and pads 8 of different thicknesses need to be gradually clamped. At the same time, the convex tail shield steel plate around it will shrink. At this time, the pads 8 corresponding to the first pier 7 need to be gradually removed to achieve the effect of correcting the whole round of the tail shield.

[0108] When the pushing deformation reaches 40-70% of the expected requirement (40mm), that is, 24mm, the pressure gradient should be slowed down and multiple pushing corrections should be performed. When the accumulated residual deformation reaches the expected requirement, the correction work at this position is stopped and the reaction support frame 3 is moved to the next position for correction.

[0109] S7, reaction support frame 3 moves

[0110] Retract the cylinder of the correction jack 5, and move the reaction support frame 3 forward and backward along the track 20 by pushing the cylinder 11 or the jack and the longitudinal pushing ring of the tooling to correct the uncorrected front and rear positions. When the accumulated residual deformation of the uncorrected position reaches the tail shield roundness standard, stop the correction work at that position.

[0111] S8, multiple rounds of correction

[0112] When the annular tooling 1 is fixed in position, the maximum deformation area is constantly changing by performing support correction operations and monitoring the roundness of the tail shield steel plate at or near the position of the maximum deformation area. The position of the meniscus is adjusted to continuously correct the deformation area, so that the 1360° correction operation of the annular tooling is achieved to the best effect; the annular tooling 1 moves from the near-center shield to the tail shield, and continuously corrects until the entire range of the tail shield is covered, which is one round of correction; the annular tooling 1 continues to be moved to the near-center shield position, the deformation status of the tail shield is monitored, and corrections are continued for multiple times until multiple rounds are completed and the roundness of the tail shield is close to the installed state.

[0113] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A method for correcting deformation of a large-diameter shield tail shield in a highly permeable sand layer using a circular tooling, characterized in that: The annular tooling comprises: a reaction force support frame, which is an annular structure, wherein the outer arc surface of the reaction force support frame is provided with first buttresses at intervals in the longitudinal direction and the circumferential direction, a pre-tightening jack is provided between the first buttresses in the longitudinal direction of the reaction force support frame, and a plurality of correction jacks are provided in the deformation area of ​​the tail shield corresponding to the outer arc surface of the reaction force support frame; A pad, which fills the gap between the first buttress and the tail shield; A meniscus structure, which is installed on the inner arc surface of the reaction support frame corresponding to the deformation area of ​​the tail shield; The reaction force support frame is composed of a number of blocks; The blocks are fixed by external flanges or welding; The cross-sections of the reaction support frame and the meniscus structure are both box structures with double rectangular cross-sections; At least two transverse partitions are arranged inside the box structure of the reaction force support frame, and a plurality of first ribs are arranged around the transverse partitions and the box structure of the reaction force support frame; A plurality of second ribs are arranged around the inner periphery of the box structure of the meniscus structure; A track extending in the longitudinal direction and located below the reaction support frame for sliding the reaction support frame. Oblique supports are arranged on both sides of the track and are reinforced by the oblique supports and the tail shield; a second buttress for supporting the track; The deformation correction method includes the following steps: S1. Determine the deformation of the tail shield; S2, installation of reaction support frame, pier and jack; S21. According to the load capacity of the segment assembly machine and the rationality of the assembly space of the reaction support frame, the reaction support frame is divided into several blocks. A group of first piers is installed on the outer arc surface of the block in the gap between every 1 to 5 groups of thrust cylinders. The first pier in each group of first piers is arranged along the longitudinal direction of the shield machine, and pre-tightening jacks are placed between the first piers; several correction jacks are installed on the outer arc surface of the block corresponding to the local deformation area of ​​the shield tail steel plate, and pads of different thicknesses are prepared for filling between the first pier and the tail shield; S22, when assembling the reaction support frame, the assembling machine uses the tooling arc plate to grab the block and rotate it to the top of the assembling machine, and fix the first pier and the pre-tightening jack between the first piers to the outer arc surface of the block; the first pier and the pre-tightening jack are respectively fixed to the outer arc surface of the block; S23, rotating the blocks to the top of the assembly machine, using a hand chain hoist to place the correction jack on the outer arc surface of the reaction support frame, fixing the correction jack to the flat flange of the outer arc surface of the reaction support frame, and then rotating the assembly machine to the assembly area of ​​the reaction support frame to install the blocks; S3, the reaction support frame is assembled in blocks; S31, the blocks of the reaction support frame are assembled symmetrically from the bottom, and finally the top block is inserted; S4, meniscus structure installation; The meniscus structure is symmetrically divided into blocks, which are transported to the trolley by a capacitor car, and the vacuum suction cup is removed. The trolley is lifted to the sheet feeder and transported to the bottom of the ring beam. At this time, the segment assembly machine is used to install the tooling cantilever, and the ring beam and tail shield welding hook hanging hoist is used to turn over and install them in place. According to the deformation position, the meniscus is installed to the corresponding deformation position. If there are multiple deformation positions, the meniscus combined with the correction jack can form a full circle correction. S5, graded pressurization After the whole circle of reaction force support frame is pre-tightened, the hydraulic pump station is activated to synchronously pressurize several correction jacks in stages. After each stage of pressurization reaches the set pressure, the pressure is maintained for 15 to 30 minutes. The deformation monitoring of the tail shield weld and deformation part and the stress monitoring of the circular reaction force support frame are carried out. At the same time, it is observed whether there is any abnormal displacement of each structure. If there is no abnormality, the next stage of pressure is pressurized as required; S6, push correction The thrust correction target is set to a shield tail clearance of no less than 4 cm at the maximum deformation point. During the correction, intermittent sand removal and decompression are performed. During the process of the correction jack pushing, the concave and deformed tail shield steel plate develops outwards, and pads of different thicknesses need to be gradually inserted. At the same time, the convex tail shield steel plate around it will shrink. At this time, the pads of the corresponding piers need to be gradually removed to achieve the effect of correcting the tail shield as a whole. When the pushing deformation reaches 40-70% of the expected requirement, the pressure gradient should be slowed down and multiple pushing corrections should be performed. When the accumulated residual deformation reaches the expected requirement, the correction work at this position should be stopped and the reaction support frame should be moved to the next position for correction. S7, reaction support frame movement Retract the correction jack, push the ring longitudinally, and move the reaction support frame forward and backward along the track to correct the uncorrected positions. When the accumulated residual deformation of the uncorrected position reaches the tail shield roundness standard, stop the correction work at that position; S8, multiple rounds of correction When the circular tooling is fixed in position, the maximum deformation area is constantly changing by performing support correction operations and monitoring the roundness of the tail shield steel plate at or near the position of the maximum deformation area. The position of the meniscus is adjusted to continuously correct the deformation area, thereby achieving 360° correction operations of the circular tooling; the circular tooling moves from the near-center shield to the tail shield, and continuously corrects until the entire range of the tail shield is covered, which is one round of correction; the circular tooling continues to be moved to the near-center shield position, the deformation of the tail shield is monitored, and corrections are continued for multiple times until multiple rounds are completed and the roundness of the tail shield is close to the installed state.

2. The method for correcting deformation of the tail shield of a large-diameter shield machine in a highly permeable sand layer using a circular tool as claimed in claim 1, characterized in that: Specifically, S1 is as follows: during the continuous excavation of the shield machine, the tail shield gap of each ring segment is measured and collected, and the gap between the cylinder support shoe and the tail shield steel plate is periodically observed. If these two gaps exceed the standard or are abnormal, the surveyor should use a total station to measure the roundness of the tail shield. If conditions permit, the ring segment with the abnormal gap should be removed, and a larger space should be reserved longitudinally for the tail shield to measure as many cross sections as possible.

3. The method for correcting deformation of the tail shield of a large-diameter shield machine in a highly permeable sand layer using a circular tool as claimed in claim 1, characterized in that: Intermittent sand discharge and pressure relief are specifically as follows: a pressure relief hole is opened below the area with large deformation at the shield tail, and the pressure relief hole is opened to release sand before or during the jacking correction. The pressure relief hole avoids the jacking correction area, the shield tail pipeline and the location of the first pier. After the tail shield correction construction is completed, the tail shield opening needs to be sealed.

4. The method for correcting deformation of the tail shield of a large-diameter shield machine in a highly permeable sand layer using a circular tool as claimed in claim 1, characterized in that: The S21 also includes setting a track at the bottom of the reaction support frame, and lining the bottom of the track with a second pier, the track serving as a moving path for the reaction support frame, and a plurality of second piers extending from the front end of the reaction support frame to the front end of the current segment at intervals, and oblique supports are set on both sides of the track and reinforced by welding with the tail shield; after the second pier and the track are installed, the height is measured and checked and fitted so that the height of the reaction support frame meets the requirements when it falls on the first pier and the track, and the lower part of the pad track is adjusted to be consistent in radial direction if necessary.

5. The method for correcting deformation of the tail shield of a large-diameter shield machine in a highly permeable sand layer using a circular tool as claimed in claim 1, characterized in that: The S31 is specifically as follows: after the bottom block of the reaction support frame is installed and positioned and consolidated, the adjacent blocks on both sides are installed and crossed in sequence; each time a block is assembled, the block bolts are installed and tightened, and then spot welded and fixed. After the whole ring reaction support frame is assembled, the pre-tightening jacks embedded between the first piers are used to load evenly, and the bolts between the blocks are tightened again and the longitudinal seams of the reaction support frame blocks are welded and fixed; when installing the blocks above the center line, the auxiliary tooling 7-shaped hooks need to be supplemented with welding on the tail shield to temporarily hang the upper block, and the segment assembly machine shall not be moved before the 7-shaped hooks are welded; The suction of a single block includes: before the vacuum suction cup sucks the curved steel plate, it is first fixed on the vacuum suction cup through a positioning pin, a sealing gasket is installed between the positioning pin and the curved steel plate for sealing, and then the vacuum pump is turned on to suck the curved steel plate tightly, and the positioning pin is tightened at the same time; After the assembling machine sucks up the curved steel plate, a number of screw rods are welded on the outer curved surface of the curved steel plate and fixed one by one with the outer flange of the reaction support frame.

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