Pipe jacking system based on multiple casing pipes and jacking method

Abstract

The invention discloses a pipe jacking system based on multiple casing pipes and a jacking method, and belongs to the technical field of underground engineering construction. The pipe jacking system comprises a jack and a heading machine and further comprises a sleeve assembly, the heading machine is installed at the front end of the sleeve assembly, and the jack is used for jacking the rear end of the sleeve assembly. The sleeve assembly at least comprises an outer-layer pipe and an inner-layer pipe which are connected in a sliding mode, and a supporting pad is arranged in a pipe gap formed by the outer-layer pipe and the inner-layer pipe. Grouting holes are formed in the pipe walls of the inner-layer pipe and the outer-layer pipe; the shield tail of the heading machine is provided with an underground grouting system which is connected with an external ground grouting system. According to the pipe jacking system, during construction, the steps of outer-layer pipe jacking, inner-layer pipe inserting and inner-layer pipe jacking are adopted, the frictional resistance between the inner-layer pipe and a soil body is reduced, the frictional resistance in the whole casing pipe assembly jacking process is greatly reduced, meanwhile, accumulated disturbance caused by movement of the casing pipe assembly is reduced, and the construction efficiency is improved. And the protection of the proximity infrastructure is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of underground engineering construction, and in particular to a pipe jacking system and a jacking method based on multiple casings. Background Art

[0002] Pipe jacking technology is an indispensable key technology in the construction of urban lifeline projects. It does not block traffic, has little disturbance and is fast when constructing in complex environments. It shows natural technical advantages, especially when crossing railways, water bodies and existing key infrastructure. However, with the acceleration of urbanization, pipe jacking construction faces increasing technical challenges. First, the technical requirements for long-distance jacking construction have increased significantly, especially in the fields of trunk pipeline construction such as water supply, drainage and power transmission, which require a single jacking distance of more than 1,000 meters, posing a severe test to existing technologies. Secondly, in pipe jacking construction, the pipeline train needs to be moved as a whole to the destination. During the construction process, a uniform lubrication layer must be maintained on the outer periphery of the jacking pipe. As the construction distance increases and time passes, the lubrication layer is easily degraded due to factors such as soil changes or groundwater fluctuations, resulting in a sharp increase in construction friction, which not only limits the jacking distance, but also threatens the safety of the pipe segment structure. At the same time, long-distance pipe jacking often requires the construction of multiple working pits, which has a significant impact on site utilization, construction schedule and environmental protection. Especially when crossing ultra-close infrastructure, the cyclic disturbance of pipe jacking construction can easily lead to damage and deformation of existing infrastructure. Finally, when relying on traditional jacking technology close to its limit, the construction risk increases significantly, resulting in higher uncertainty for the construction unit. Once a problem occurs, it will not only bring huge economic losses, but also may have a serious impact on construction safety and the surrounding environment. Therefore, long-distance pipe jacking construction faces two technical difficulties: increased friction and cyclic disturbance, and it is urgent to explore more optimized technical solutions. Summary of the invention

[0003] In view of the above-mentioned problems, the present invention aims to provide a pipe jacking system and a jacking method based on multiple casings, which adopts the steps of outer pipe jacking-inner pipe insertion-inner pipe jacking, thereby reducing the frictional resistance between the inner pipe and the soil, thereby greatly reducing the frictional resistance during the jacking process of the entire casing assembly, and successfully realizing efficient pipe jacking construction under ultra-long distances (far exceeding 10,000 meters) and ultra-close conditions, providing an innovative solution for the sustainable development of trenchless laying technology for municipal pipelines.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A pipe jacking system based on multiple casings, comprising a jack and a tunneling machine; further comprising a casing assembly, wherein the tunneling machine is installed at the front end of the casing assembly, and the jack is used to jack the rear end of the casing assembly; The casing assembly at least comprises an outer tube and an inner tube arranged inside and outside, and both the outer tube and the inner tube are detachably connected to the tunneling machine; The shield tail of the tunnel boring machine is provided with an underground grouting system, and the underground grouting system is connected with an external ground grouting system.

[0005] Furthermore, the outer tube is coaxially arranged with the inner tube, and a support pad is provided in the tube gap formed by the outer tube and the inner tube; A plurality of gap sealing rings are axially mounted on the outer side of the inner tube, and the gap sealing rings cooperate with the support pads to seal the tube gaps.

[0006] Furthermore, an inner layer tube grouting hole is opened on the side wall of the inner layer tube, and an outer layer tube grouting hole is opened on the outer layer tube.

[0007] Furthermore, a cutter disc is installed at the front end of the tunnel boring machine, and a retractable contour knife is installed on the outer edge of the cutter disc.

[0008] Furthermore, an adapter pipe is provided at the rear end of the tunnel boring machine, and an extension pipe for connecting the inner layer pipe and the outer layer pipe is provided at the rear end of the adapter pipe, and the extension pipe is symmetrical with the inner layer pipe and the outer layer pipe and is detachably provided with four connecting bolts; The pipe jacking system also includes a disassembly and assembly auxiliary component for synchronously adjusting the four connecting bolts.

[0009] Furthermore, the disassembly and assembly auxiliary component includes a shell, on which four first telescopic rods are symmetrically and rotatably connected, the ends of the first telescopic rods are provided with first square pins, and the heads of the connecting bolts are provided with first square grooves corresponding to the first square pins.

[0010] Furthermore, a bidirectional motor is installed in the housing, and both output ends of the bidirectional motor are connected to a first mounting column, and two second mounting columns perpendicular to the first mounting columns are rotatably connected to the side wall of the housing; A first bevel gear is sleeved on one of the first mounting columns, and a second bevel gear meshing with the first bevel gear is sleeved on both of the second mounting columns; The first telescopic rod is mounted on both the first mounting column and the second mounting column.

[0011] Furthermore, the front end of the housing is detachably connected with a centering mechanism for connecting the adapter tube; The centering mechanism comprises a center disk, and the housing is detachably connected to the center disk; A plurality of second telescopic rods are arranged on the outer periphery of the central disk, and suction cups are arranged on the ends of the second telescopic rods.

[0012] Further, the casing assembly also includes an intermediate tube; The middle tube is located between the outer tube and the inner tube, and the support pad is arranged between the outer tube and the middle tube, and between the middle tube and the inner tube.

[0013] On the other hand, the present invention also provides a jacking method based on a multi-casing jacking system as described above, comprising the following steps: S1: Install the jack in the working well; S2: Connect the rear end of the tunnel boring machine to the outer layer pipe, adjust the diameter of the cutter head of the tunnel boring machine so that the excavation section is 10mm to 40mm larger than the size of the outer layer pipe; connect the underground grouting system with the ground grouting system; S3: Start the jack, and the jacking force of the jack is transmitted to the tunnel boring machine through the outer pipe. The tunnel boring machine excavates the soil and pushes the outer pipe into the soil at the same time; At the same time, grouting lubrication is carried out between the soil and the outer pipe through the underground grouting system and the ground grouting system to reduce the resistance of the outer pipe during excavation; S4: When the tunnel boring machine has passed through the existing near-pipe line or existing structure, the outer pipe stops pushing forward; the inner pipe is pushed forward into the outer pipe by a jack; when the inner pipe is close to the tunnel boring machine, the inner pipe is connected to the tunnel boring machine; S5: Adjust the cutter head diameter of the tunnel boring machine so that the diameter of the excavated section is 20mm-40mm larger than the diameter of the inner pipe. The jack continues to push the inner pipe forward until it reaches the receiving well.

[0014] The beneficial effects of the present invention are: 1. The jacking system of the present invention adopts the steps of outer-layer pipe jacking-inner-layer pipe insertion-inner-layer pipe jacking during construction. When the inner-layer pipe is jacked into the outer-layer pipe, the inner-layer pipe does not bear the overburden load, but only the friction resistance caused by its own weight. The required jacking force is small and the advancement speed is fast. When the inner-layer pipe is jacked into the soil, only the contact part between the inner-layer pipe and the soil generates friction resistance, thereby greatly reducing the friction resistance during the jacking process of the entire casing assembly. At the same time, it also reduces the accumulated disturbance caused by the movement of the casing assembly, which is beneficial to the protection of nearby infrastructure. It successfully realizes efficient jacking construction under ultra-long distance (far more than 1,000 meters) and ultra-close working conditions, providing an innovative solution for the sustainable development of pipeline burial technology.

[0015] 2. The jacking pipe system in the present invention is connected to the underground grouting system at the tail of the tunnel boring machine and is connected to the external ground grouting system. When either the outer layer pipe or the inner layer pipe is jacked in the soil, the frictional resistance between the soil and the pipe body can be reduced by injecting lubricating slurry between the pipe wall and the soil.

[0016] 3. The jacking system of the present invention can further add an intermediate pipe on the basis of the inner and three-layer pipes on the basis of the two-layer pipes such as the inner and outer pipes to form a three-layer pipe structure. During jacking, the outer pipe, the intermediate pipe and the inner pipe are jacked in sequence respectively, which can further increase the jacking distance on the basis of reducing frictional resistance, thereby ensuring the reliability and safety of the construction process.

[0017] 4. In order to enable rapid switching of the connection between the tunnel boring machine and the outer tube and the inner tube, the jacking pipe system of the present invention has an adapter pipe arranged between the tunnel boring machine and the outer tube and the inner tube, and the extension pipe at the rear end of the adapter pipe is connected to the inner tube and the outer tube by connecting bolts, and the connection switching between the inner tube and the outer tube and the extension pipe can be achieved by adjusting the connection length of the connecting bolts and the extension pipe; in addition, in order to be able to synchronously adjust multiple connecting bolts, the present invention also provides a disassembly and assembly auxiliary component, which can synchronously drive the two first mounting columns and the two second mounting columns to rotate when the bidirectional motor is started, and can synchronously adjust multiple connecting bolts in combination with the extension of the first telescopic rod, thereby avoiding long-time operation of workers in a limited space and improving the jacking efficiency.

[0018] 5. The pipe jacking system of the present invention is also provided with a centering mechanism, through which the disassembly and assembly auxiliary component can be detachably connected to the adapter pipe. When the disassembly and assembly auxiliary component is needed, the centering mechanism is first installed in the adapter pipe, with the center coinciding with the center of the adapter pipe, and then the disassembly and assembly auxiliary component is connected to the centering mechanism. This can avoid the instability of workers holding the disassembly and assembly auxiliary component for operation, thereby reducing the labor intensity of the workers. The centering mechanism and the disassembly and assembly auxiliary component are both detachably connected, which will not affect the normal use of the adapter pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the pipe jacking system in the first embodiment of the present invention.

[0020] Figure 2 It is a side view of the sleeve assembly structure in embodiment 1 of the present invention.

[0021] Figure 3 This is a front view of the sleeve assembly structure in Example 1 of the present invention.

[0022] Figure 4 This is a schematic diagram of the structure of the gap sealing ring in Embodiment 1 of the present invention.

[0023] Figure 5 This is a schematic diagram of the support pad structure in Example 1 of the present invention.

[0024] Figure 6 It is a schematic diagram of the structure of the inner layer pipe in the jacking state in the first embodiment of the present invention.

[0025] Figure 7It is a structural schematic diagram of the connection state of the inner tube, the outer tube and the adapter tube in the second embodiment of the present invention.

[0026] Figure 8 For the present invention Figure 7 A partial enlarged view of the structure of part A.

[0027] Fig. 9 This is a front view of the adapter tube structure in the second embodiment of the present invention.

[0028] Fig.10 It is a side view of the extension tube structure in the second embodiment of the present invention.

[0029] Fig.11 It is a side view of the disassembly and assembly auxiliary component structure in the second embodiment of the present invention.

[0030] Fig.12 This is a front view of the centering mechanism structure in the second embodiment of the present invention.

[0031] Fig.13 It is a side view of the centering mechanism structure in the second embodiment of the present invention.

[0032] Fig.14 It is a side view of the sleeve assembly structure in embodiment 3 of the present invention.

[0033] Fig.15 It is a schematic diagram of the structure of the jacking state after the jack is moved in the fifth embodiment of the present invention.

[0034] Among them: 1. Jack; 2. Tunneling machine; 201. Cutterhead; 202. Retractable contour knife; 3. Outer pipe; 301. Grouting hole of outer pipe; 302. Outer pipe connecting ring; 303. Connecting ring; 304. Connecting square rod; 4. Inner pipe; 401. Grouting hole of inner pipe; 402. Socket joint of inner pipe; 5. Underground grouting system; 6. Ground grouting system; 7. Pipe gap; 8. Support pad; 9. Gap sealing ring; 10. Adapter pipe; 1001. Extension pipe; 1002. Limiting square groove; 1003. Bolt hole; 1004. Socket slot; 1005. Sealing pad; 11. Backrest ; 12. Top iron; 13. Working well; 14. Receiving well; 15. Existing near-pipeline; 16. Existing structure; 17. Intermediate pipe; 18. Connecting bolt; 1801. First square groove; 19. Shell; 1901. Threaded rod; 1902. Second square rod; 1903. Fastening sleeve; 20. Bidirectional motor; 21. First mounting column; 22. Second mounting column; 23. First bevel gear; 24. Second bevel gear; 25. First telescopic rod; 26. First square pin; 27. Center disk; 2701. Second square groove; 2702. Threaded connection groove; 28. Second telescopic rod; 29. ​​Suction cup. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments. Embodiment 1

[0036] Refer to the attached Figure 1-6 As shown, this embodiment provides a pipe jacking system based on multiple casings, including a jack 1 and a tunnel boring machine 2, and also includes a casing assembly, wherein the tunnel boring machine 2 is installed at the front end of the casing assembly, and the jack 1 is used to jack the rear end of the casing assembly; In this embodiment, a two-layer pipe is used as an example for explanation. The casing assembly includes an outer layer pipe 3 and an inner layer pipe 4 arranged inside and outside. The outer layer pipe 3 and the inner layer pipe 4 are both detachably connected to the tunnel boring machine 2. The tail shield of the tunnel boring machine 2 is provided with an underground grouting system 5, which penetrates through the casing assembly and is connected to an external surface grouting system 6; the underground grouting system 5 and the surface grouting system 6 are used to perform grouting lubrication between the outer layer pipe 3 and the soil, and between the outer layer pipe 3 and the inner layer pipe 4. It should be noted here that the surface grouting system 6 is a pumping station, and the underground grouting system 5 is mainly a grouting pipe, which can pump the slurry through the underground grouting system 5 to the tail shield of the tunnel boring machine 2, so as to continuously perform grouting on the connection between the casing assembly and the tunnel boring machine 2, thereby reducing the resistance of the casing assembly during the tunneling process.

[0037] An inner layer pipe grouting hole 401 is opened on the side wall of the inner layer pipe 4, and an outer layer pipe grouting hole 301 is opened on the side wall of the outer layer pipe 3. A branch pipe is vertically connected to the grouting pipe of the underground grouting system 5, and the branch pipe corresponds to the inner layer pipe grouting hole 401 and the outer layer pipe grouting hole 301. When the outer layer pipe 3 is pushed forward, the branch pipe on the grouting pipe is connected to the outer layer pipe grouting hole 301 accordingly, and the grouting pipe and the outer layer pipe 3 are pushed forward synchronously, so that grouting lubrication can be performed synchronously between the outer layer pipe 3 and the soil. When the inner layer pipe 4 is pushed forward, the branch pipe on the grouting pipe is connected to the corresponding grouting hole 401 of the inner layer pipe, and the grouting pipe and the inner layer pipe 4 are pushed forward synchronously, so that when the inner layer pipe 4 is pushed forward in the outer layer pipe 3, the gap between the inner layer pipe 4 and the outer layer pipe 3 can be grouting lubricated, and when the inner layer pipe 4 is pushed outside the outer layer pipe 3 and connected to the tunneling machine 2, grouting lubrication can be performed between the inner layer pipe 4 and the soil.

[0038] Specifically, the outer tube 3 is coaxially arranged with the inner tube 4. In order to ensure the stability of the inner tube 4 during the jacking process, a support pad 8 is laid in the tube gap 7 formed by the outer tube 3 and the inner tube 4. The support pad 8 is made of flexible material, wear-resistant and smooth, which will not affect the movement of the inner tube 4 in the outer tube 3, and can disperse the contact stress between the inner tube 4 and the outer tube 3 after the construction is completed. It should be noted that both the inner tube 4 and the outer tube 3 adopt a multi-section pipe section structure, which is jacked in sections during jacking. Relay rooms can be used between the pipe sections according to the jacking requirements. This operation is a prior art and will not be described in detail in the present invention. Since the outer tube 3 needs to bear the load of the surrounding soil, steel pipes are considered to be used as pipes. The design method takes into account the jacking force and load, and the surface is smoothed. The inner layer pipe 4 can be a concrete pipe, but other types of pipes can also be used depending on the purpose of the pipeline, the buried pipe diameter and the construction method. For example, the inner layer pipe 4 can use a cast iron pipe, PVC pipe, FRPM pipe, etc. for pushing, and the outer layer pipe 3 can also choose to use a concrete pipe.

[0039] In order to prevent the inner tube 4 from axially deflecting during the jacking process and reduce the probability of hard contact between the inner tube 4 and the outer tube 3, a plurality of gap sealing rings 9 are axially installed on the outer side of the inner tube 4. The gap sealing rings 9 cooperate with the support pads 8 to seal the tube gaps 7.

[0040] Furthermore, a cutter head 201 is installed at the front end of the tunnel boring machine 2, and a retractable profiling knife 202 is installed at the outer edge of the cutter head 201. The retractable profiling knife 202 is used to adjust the diameter of the excavation section. The rear end of the tunnel boring machine 2 is connected to the front end of the inner layer pipe 4 or the outer layer pipe 3 through an adapter pipe 10. When the outer pipe 3 is pushed forward, the rear end of the adapter pipe 10 is connected to the outer pipe 3, and the jack 1 in the working well 13 applies a pushing force to the outer pipe 3, and transmits the pushing force to the tunnel boring machine 2 through the outer pipe 3, and the tunnel boring machine 2 excavates the soil; when the inner pipe 4 is pushed forward, the outer pipe 3 does not move, and the inner pipe 4 first moves in the outer pipe 3. When the front end of the inner pipe 4 moves to the front end of the outer pipe 3, the front end of the inner pipe 4 is connected to the adapter pipe 10, and the jack 1 continues to push the inner pipe 4, and the pushing force of the jack 1 is transmitted to the tunnel boring machine 2 through the inner pipe 4, and the tunnel boring machine 2 further excavates the soil until it reaches the receiving well 14.

[0041] Furthermore, a backrest 11 is installed on the side wall of the working well 13 to prevent the reaction force of the jack 1 from damaging the working well 13; a top iron 12 is installed at the front end of the jack 1, and the top iron 12 is used to perform equal pressure jacking on the inner layer pipe 4 or the outer layer pipe 3. It should be noted here that the diameter of the top iron 12 needs to be adjusted and replaced according to the inner layer pipe 4 or the outer layer pipe 3 being jacked at present.

[0042] Furthermore, two adjacent outer layer tubes 3 are connected via an outer tube connecting ring 302 , and two adjacent inner layer tubes 4 are connected via an inner tube socket joint 402 .

[0043] The jacking method of the pipe jacking system in the present invention specifically comprises the following steps: S1: Install the backrest 11 and the jack 1 in the working well 13, and install the top iron 12 matching the diameter of the outer tube 3 at the front end of the jack 1; S2: Connect the rear end of the tunnel boring machine 2 to the outer layer pipe 3 through the adapter pipe 10, unfold the retractable contour knife 202 on the outer edge of the cutter head 201 of the tunnel boring machine 2, so that the excavation section is 20mm to 50mm larger than the size of the outer layer pipe 3; connect the underground grouting system 5 to the ground grouting system 6; S3: starting the jack 1, the jacking force of the jack 1 is transmitted to the tunnel boring machine 2 through the outer layer pipe 3, the tunnel boring machine 2 excavates the soil and pushes the outer layer pipe 3 into the soil at the same time; At the same time, grouting lubrication is performed between the soil and the outer pipe 3 through the underground grouting system 5 and the ground grouting system 6 to reduce the resistance of the outer pipe 3 during the excavation process; S4: After the tunnel boring machine 2 has passed through the existing near-pipeline 15 or the existing structure 16, or the requirements for the inner layer pipe 4 to be pushed are met, the outer layer pipe 3 stops pushing, and the top iron 12 matching the diameter of the inner layer pipe 4 is replaced at the front end of the jack 1; the inner layer pipe 4 is pushed into the outer layer pipe 3 by the jack 1. At this time, the inner layer pipe 4 does not bear the overburden load, and the pushed part in the outer layer pipe 3 only bears the friction caused by its own weight. The required pushing force is small and the pushing speed is fast. When the inner layer pipe 4 reaches the position of the adapter pipe 10, the inner layer pipe 4 is connected to the adapter pipe 10 (the outer layer pipe 3 is disconnected from the adapter pipe 10).

[0044] S5: retract the retractable profiling knife 202 on the outer edge of the cutter head 201 of the tunnel boring machine 2, so that the diameter of the excavated section of the retractable profiling knife 202 is 20mm-40mm larger than the diameter of the inner tube 4, and the jack 1 continues to push the inner tube 4. The jacking force of the jack 1 is transmitted to the tunnel boring machine 2 through the inner tube 4. The tunnel boring machine 2 continues to excavate the soil and pushes the inner tube 4 into the soil until it reaches the receiving well 14. At this time, the underground grouting system 5 and the ground grouting system 6 continue to work, grouting between the inner tube 4 and the soil to reduce the frictional resistance of the inner tube 4. Since the outer tube 3 is stationary, only the inner tube 4 at the front end of the outer tube 3 contacts the soil for pushing, which greatly reduces the frictional resistance between the inner tube 4 and the soil, and also reduces the accumulated disturbance caused by the overall movement of the pipe array, which is beneficial to protect the existing adjacent facilities. Embodiment 2

[0045] On the basis of the first embodiment, the second embodiment provides a connection method of the adapter tube 10 with the inner tube 4 and the outer tube 3, as shown in the attached Figure 7-13 shown.

[0046] Specifically, the rear end of the adapter tube 10 is provided with an extension tube 1001 for connecting the inner tube 4 and the outer tube 3. The extension tube 1001 and the inner tube 4 and the outer tube 3 are symmetrically and detachably provided with four connecting bolts 18. By adjusting the connection length between the connecting bolts 18 and the extension tube 1001, the connection switching between the extension tube 1001 and the inner tube 4 or the outer tube 3 can be achieved.

[0047] More specifically, the outer tube 3 is made of a steel tube with a small thickness. A circle of connecting rings 303 is provided on the inner side wall of the outer tube 3. Four connecting square rods 304 are symmetrically provided on the connecting rings 303. Four limiting square grooves 1002 matching the connecting square rods 304 are provided on the rear end surface of the extension tube 1001. The connecting square rods 304 are provided with threaded holes matching the connecting bolts 18. When connecting the outer tube 3 and the extension tube 1001, the connecting square rods 304 are first inserted into the corresponding limiting square grooves 1002, and then the connecting bolts 18 are screwed into the corresponding threaded holes of the connecting square rods 304 from the inside of the extension tube 1001, so that the extension tube 1001 and the outer tube 3 can be connected; similarly, the connecting bolts 18 can be screwed out of the connecting square rods 304 to realize the disassembly of the outer tube 3 and the extension tube 1001. The side wall of the extension tube 1001 is provided with bolt holes 1003 matching the connecting bolts 18 , and the bolt holes 1003 are connected to the limiting square grooves 1002 in a one-to-one correspondence.

[0048] The inner tube 4 is a concrete tube with a large thickness. A circle of receiving slots 1004 can be directly opened on the rear end surface of the extension tube 1001. The receiving plug of the inner tube 4 is inserted into the receiving slots 1004, and a threaded hole matching the connecting bolt 18 is also opened on the receiving plug of the inner tube 4. The connecting bolt 18 is first unscrewed from the outer tube 3, and then the inner tube 4 is inserted into the receiving slots 1004, and then the connecting bolt 18 is screwed into the threaded hole of the inner tube 4, and the end of the connecting bolt 18 is located between the receiving slots 1004 and the limiting square groove 1002, so that the connection between the inner tube 4 and the extension tube 1001 can be realized, and at the same time, the outer tube 3 and the extension tube 1001 are in a non-connected state.

[0049] Furthermore, in order to improve the sealing performance between the extension tube 1001 and the outer tube 3 and the inner tube 4, a sealing gasket 1005 is provided between the receiving slot 1004, the limiting square groove 1002 and the end of the outer tube 3 and the extension tube 1001.

[0050] Furthermore, in order to be able to synchronously adjust the screwing in and out of the four connecting bolts 18, the jacking system also includes a disassembly and assembly auxiliary component, through which the four connecting bolts 18 can be synchronously adjusted to avoid workers working for a long time in a small space.

[0051] Specifically, the disassembly and assembly auxiliary component includes a shell 19, which is a square structure. A bidirectional motor 20 is installed in the shell 19. The two output ends of the bidirectional motor 20 are connected to a first mounting column 21. The first mounting column 21 rotates through the shell 19. The side wall of the shell 19 is also rotatably connected to two second mounting columns 22 that are perpendicular to the first mounting columns 21; the two first mounting columns 21 and the two second mounting columns 22 correspond to the four connecting bolts 18 one by one. A first bevel gear 23 is sleeved on one of the first mounting columns 21, and a second bevel gear 24 that is meshed with the first bevel gear 23 is sleeved on the two second mounting columns 22. When the bidirectional motor 20 is working, it synchronously drives the two first mounting columns 21 to rotate. The first mounting column 21 synchronously drives the two second mounting columns 22 to rotate through the meshing of the first bevel gear 23 and the second bevel gear 24.

[0052] The first telescopic rod 25 is installed on both the first mounting column 21 and the second mounting column 22. The first telescopic rod 25 has a first square pin 26 at its end. The head of the connecting bolt 18 has a first square slot 1801 corresponding to the first square pin 26. The first square pin 26 is inserted into the corresponding first square slot 1801. When the first mounting column 21 and the second mounting column 22 rotate, the corresponding first telescopic rod 25 is driven to rotate. At the same time, the first telescopic rod 25 is extended and retracted, which can drive the connecting bolt 18 to be screwed in or out.

[0053] Furthermore, in order to improve the ease of use and stability of the disassembly and assembly auxiliary components, a centering mechanism for connecting the adapter tube 10 is detachably connected to the front end of the shell 19; when using the functional disassembly and assembly auxiliary components to adjust the four connecting bolts 18, the centering mechanism is first installed in the adapter tube 10, with the center coinciding with the center of the adapter tube 10, and then the disassembly and assembly auxiliary components are installed at the rear end of the centering mechanism, which can avoid instability when workers hold the disassembly and assembly auxiliary components for operation.

[0054] Specifically, the centering mechanism includes a center disk 27, a plurality of second telescopic rods 28 are arranged on the periphery of the center disk 27, and a suction cup 29 is arranged at the end of the second telescopic rod 28. By extending and retracting the second telescopic rod 28, the suction cup 29 is adsorbed on the inner wall of the adapter tube 10, so that the connection between the entire centering mechanism and the adapter tube 10 can be achieved. It should be noted here that both the first telescopic rod 25 and the second telescopic rod 28 are electric telescopic rods, and the plurality of first telescopic rods 25 are synchronously controlled, and the plurality of second telescopic rods 28 are synchronously controlled.

[0055] A threaded rod 1901 is connected to the center of the front end of the shell 19, and a second square rod 1902 is provided at the front end of the threaded rod 1901. A second square groove 2701 corresponding to the second square rod 1902 is provided at the center of the center disk 27. A fastening sleeve 1903 is threadedly connected to the threaded rod 1901, and a circle of threaded connection grooves 2702 matching the fastening sleeve 1903 is provided on the center disk 27. The shell 19 and the center disk 27 can be detachably connected by the mutual cooperation between the second square rod 1902 and the second square groove 2701, and the mutual cooperation between the fastening sleeve 1903 and the threaded connection groove 2702.

[0056] In this embodiment, the specific connection process of the outer layer tube 3 and the inner layer tube 4 with the adapter tube 10 includes the following steps: When the outer tube 3 is pushed forward, the connecting square rod 304 is inserted into the corresponding limiting square groove 1002, and the suction cup 29 is adsorbed on the inner wall of the adapter tube 10 by adjusting the length of the second telescopic rod 28, so as to realize the connection between the entire centering mechanism and the adapter tube 10. Then the second square rod 1902 at the front end of the shell 19 is inserted into the second square groove 2701, and the fastening sleeve 1903 is screwed into the threaded connection groove 2702 to realize the connection between the disassembly and assembly auxiliary component and the centering mechanism. Finally, the bidirectional motor 20 is started to drive the four first telescopic rods 25 to rotate. At the same time, the first telescopic rod 25 is extended, so that the four connecting bolts 18 can be synchronously screwed into the threaded holes of the corresponding connecting square rods 304, so as to realize the connection between the outer tube 3 and the adapter tube 10. When it is necessary to disassemble the disassembly and assembly auxiliary component and the connecting bolt 18, it is only necessary to control the shortening of the first telescopic rod 25 so that the first telescopic rod 25 is separated from the connecting bolt 18.

[0057] When pushing the inner tube 4 forward, it is necessary to first disassemble the extension tube 1001 and the outer tube 3, first insert the first square pin 26 at the end of the first telescopic rod 25 into the corresponding first square groove 1801, start the bidirectional motor 20, drive the first telescopic rod 25 to rotate, and at the same time, control the first telescopic rod 25 to retract, so that the connecting bolt 18 can be removed from the connecting square rod 304; then insert the socket plug of the inner tube 4 into the socket slot 1004 of the extension tube 1001, and then screw the connecting bolt 18 into the threaded hole of the inner tube 4, and the end of the connecting bolt 18 is located between the socket slot 1004 and the limiting square groove 1002, so that the connection between the inner tube 4 and the extension tube 1001 can be realized, and at the same time, the outer tube 3 and the extension tube 1001 are in a non-connected state. Embodiment 3

[0058] Embodiment 3 Based on the embodiment 1, the casing assembly can also use a three-layer tube, in addition to the outer tube 3 and the inner tube 4, an intermediate tube 17 can be set between the outer tube 3 and the inner tube 4, and a support pad 8 is set between the outer tube 3 and the intermediate tube 17, and a support pad 8 is also set between the intermediate tube 17 and the inner tube 4; and gap sealing rings 9 are arranged on the outer side walls of the intermediate tube 17 and the inner tube 4; the intermediate tube 17 can slide in the outer tube 3, and the inner tube 4 can slide in the intermediate tube 17, as shown in the attached Fig.14 shown.

[0059] During jacking, the outer pipe 3 is jacked first. When the jacking requirement of the intermediate pipe 17 is reached, the position of the outer pipe 3 remains unchanged, and the intermediate pipe 17 is jacked. When the intermediate pipe 17 is jacked into the soil and the jacking requirement of the inner pipe 4 is reached, the positions of the outer pipe 3 and the intermediate pipe 17 remain unchanged, and only the inner pipe 4 is jacked. In this way, efficient jacking construction can be achieved under ultra-long distance (far more than 1,000 meters) and ultra-close working conditions. Embodiment 4

[0060] As another embodiment, on the basis of the embodiment 1, the embodiment 4 can connect the outer layer pipe 3 and the inner layer pipe 4 with a clamp before the jacking operation, the inner layer pipe 4 is connected to the boring machine 2, and the jack 1 pushes the inner layer pipe 4, and the jacking force of the jack 1 is only transmitted from the inner layer pipe 4 to the boring machine 2, and the outer layer pipe 3 moves synchronously with the pushing of the inner layer pipe 4; when the outer layer pipe 3 moves to the desired position, the clamp is cut off, the outer layer pipe 3 is no longer pushed with the inner layer pipe 4, and the inner layer pipe 4 is pushed alone to the receiving well 14. The jacking method of the three-layer pipe in the embodiment 3 is similar. Embodiment 5

[0061] As another embodiment, in the fifth embodiment, the jack 1 can be moved forward in the outer tube 3, and then the jack 1 can be used to continue to push the inner tube 4, so as to further extend the pushing distance. Fig.15 shown.

[0062] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A pipe jacking system based on multiple casings, comprising a jack (1) and a tunnel boring machine (2); characterized in that: It also includes a casing assembly, the tunneling machine (2) is installed at the front end of the casing assembly, and the jack (1) is used to push the rear end of the casing assembly; The casing assembly comprises at least an outer layer pipe (3) and an inner layer pipe (4) which are arranged inside and outside the casing, and the outer layer pipe (3) and the inner layer pipe (4) are both detachably connected to the tunnel boring machine (2); The shield tail of the tunnel boring machine (2) is provided with an underground grouting system (5), and the underground grouting system (5) is connected to an external ground grouting system (6).

2. The multi-casing based pipe jacking system according to claim 1, characterized in that: The outer layer tube (3) and the inner layer tube (4) are coaxially arranged, and a support pad (8) is provided in a tube gap (7) formed by the outer layer tube (3) and the inner layer tube (4); A plurality of gap sealing rings (9) are axially mounted on the outer side of the inner layer tube (4); the gap sealing rings (9) cooperate with the support pad (8) to seal the tube gap (7).

3. The multi-casing based pipe jacking system according to claim 2, characterized in that: An inner layer pipe grouting hole (401) is provided on the side wall of the inner layer pipe (4), and an outer layer pipe grouting hole (301) is provided on the outer layer pipe (3).

4. The multi-casing based pipe jacking system according to claim 1, characterized in that: A cutterhead (201) is installed at the front end of the tunnel boring machine (2), and a retractable contour knife (202) is installed at the outer edge of the cutterhead (201).

5. The multi-casing based pipe jacking system according to claim 1, characterized in that: The rear end of the tunnel boring machine (2) is provided with an adapter pipe (10), the rear end of the adapter pipe (10) is provided with an extension pipe (1001) for connecting the inner layer pipe (4) and the outer layer pipe (3), and the extension pipe (1001) is symmetrically and detachably provided with four connection bolts (18) between the inner layer pipe (4) and the outer layer pipe (3); The pipe jacking system also includes a disassembly and assembly auxiliary component for synchronously adjusting the four connecting bolts (18).

6. The multi-casing based pipe jacking system according to claim 5, characterized in that: The disassembly and assembly auxiliary component comprises a shell (19), four first telescopic rods (25) are symmetrically and rotatably connected to the shell (19), a first square pin (26) is provided at the end of the first telescopic rod (25), and a first square groove (1801) corresponding to the first square pin (26) is formed at the head of the connecting bolt (18).

7. The multi-casing based pipe jacking system according to claim 6, characterized in that: A bidirectional motor (20) is installed in the housing (19), two output ends of the bidirectional motor (20) are connected to a first mounting column (21), and two second mounting columns (22) that are perpendicular to the first mounting columns (21) are rotatably connected to the side wall of the housing (19); A first bevel gear (23) is sleeved on one of the first mounting columns (21), and a second bevel gear (24) meshing with the first bevel gear (23) is sleeved on both of the second mounting columns (22); The first telescopic rod (25) is mounted on both the first mounting column (21) and the second mounting column (22).

8. The multi-casing based pipe jacking system according to claim 7, characterized in that: The front end of the housing (19) is detachably connected to a centering mechanism for connecting to the adapter tube (10); The centering mechanism comprises a center disk (27), and the housing (19) is detachably connected to the center disk (27); A plurality of second telescopic rods (28) are provided on the outer periphery of the central disk (27), and suction cups (29) are provided at the ends of the second telescopic rods (28).

9. The multi-casing based pipe jacking system according to any one of claims 1 to 8, characterized in that: The casing assembly also includes an intermediate tube (17); The intermediate tube (17) is located between the outer tube (3) and the inner tube (4), and the support pad (8) is provided between the outer tube (3) and the intermediate tube (17), and between the intermediate tube (17) and the inner tube (4).

10. The jacking method based on a multi-casing jacking system according to any one of claims 1 to 8, characterized in that: The following steps are included: S1: Install the jack (1) in the working well (13); S2: Connect the rear end of the tunnel boring machine (2) to the outer layer pipe (3), adjust the diameter of the cutter head of the tunnel boring machine (2) so that the excavation section is 20 mm to 50 mm larger than the size of the outer layer pipe (3); connect the underground grouting system (5) to the ground grouting system (6); S3: starting the jack (1), the jacking force of the jack (1) is transmitted to the tunnel boring machine (2) through the outer layer pipe (3), the tunnel boring machine (2) excavates the soil, and at the same time pushes the outer layer pipe (3) into the soil; At the same time, grouting lubrication is performed between the soil and the outer layer pipe (3) through the underground grouting system (5) and the ground grouting system (6), thereby reducing the resistance of the outer layer pipe (3) during the excavation process; S4: After the tunnel boring machine (2) has passed through the existing near-pipeline (15) or the existing structure (16), the outer pipe (3) stops being pushed forward; the inner pipe (4) is pushed forward into the outer pipe (3) by means of the jack (1); when the inner pipe (4) is close to the tunnel boring machine (2), the inner pipe (4) is connected to the tunnel boring machine (2); S5: The cutter head diameter of the tunnel boring machine (2) is adjusted so that the diameter of the excavated section is 20 mm to 40 mm larger than the diameter of the inner layer pipe (4), and the jack (1) continues to push the inner layer pipe (4) until it reaches the receiving well (14).

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