A ring-cut steel blade foot device for pipe jacking construction in soft soil environment

Abstract

The present invention discloses a ring-cutting steel blade foot device for pipe jacking construction in a soft foundation silt environment, comprising a socket pipe and a steel blade foot assembly, wherein the steel blade foot assembly is arranged at one end of the socket pipe penetrating into the inside of the stratum, and two groups of support brackets for supporting the lateral movement of the socket pipe are arranged on the front and rear sides of the stratum, and a cast-in-place reaction wall is arranged on the side of the stratum away from the steel blade foot assembly, and a driving assembly for pushing the socket pipe into the stratum is arranged on the inner side of the cast-in-place reaction wall. The beneficial effect is that the present invention solves the influence of repeated installation of the jacking iron on the construction efficiency by adding a group of extension frames with a stepped structure in the working pit of the stratum, and using the extension frames to replace the assembled jacking iron in the existing jacking process as a force transmission mechanism, and increases the stability of the oil cylinder on the jacking action of the socket pipe, avoiding the risk of distortion and collapse of multiple groups of jacking irons spliced ​​head to tail during the jacking process, and further improving the construction safety and construction efficiency.

Description

Technical Field

[0001] The invention relates to the field of pipe jacking construction, and in particular to a ring-cutting steel blade foot device for pipe jacking construction in a soft-base silt environment. Background Art

[0002] Pipe jacking is a pipeline burial construction technology that does not involve excavation or requires minimal excavation. Specifically, the jacking force generated by the jacking equipment in the working pit overcomes the friction between the pipeline and the surrounding soil, pushes the pipeline into the soil according to the designed slope, and removes the soil. After one section of the pipe is completely pushed into the soil layer, the second section of the pipe is pushed in. The principle is to use the thrust of the main jacking cylinder to push the tool pipe from the working pit through the soil layer to the receiving pit. Pipe jacking is another underground pipeline construction method developed after shield construction. It does not require excavation of the surface layer and can pass under roads, railways, rivers, ground buildings, underground structures and various underground pipelines, etc., so it has been widely used in recent years.

[0003] When the pipe jacking construction passes through the soft foundation silt below the groundwater level, the ground is prone to uplift and subsidence during the implementation process due to the soft structure and low bearing capacity of the stratum, causing deformation and damage to the pipe jacking; and during the jacking process, since the cylinder stroke is less than the length of a single-section bell-and-spigot pipe, a jacking iron needs to be set in the actual jacking process to transmit the cylinder jacking force. The specific operation is that after the piston extends a working stroke and pushes the pipe into the soil layer for a certain distance, the cylinder returns oil and contracts, and a set of jacking irons is added between the telescopic end of the cylinder and the bell-and-spigot pipe. The cylinder extension action is repeated again to achieve the next jacking action with the help of the jacking iron, so as to repeat the above operation, by adding multiple sets of jacking irons matching the cylinder extension stroke, until a set of pipes is completely pushed into the soil layer. During the operation, the jacking irons need to be frequently disassembled and assembled, and multiple sets of jacking irons are connected end to end as a medium for transmitting power. In actual use, there is a risk of distortion or even collapse due to excessive force. Summary of the invention

[0004] The purpose of the present invention is to provide a ring-cut steel blade foot device for pipe jacking construction in a soft foundation and silt environment in order to solve the above-mentioned problems. By arranging a multi-piece assembled steel blade foot at the end of the bell and spigot pipe, the pushing resistance during the jacking process of the bell and spigot pipe is reduced, the construction efficiency is improved, and the installation is simple, as described below for details.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a ring-cutting steel blade foot device for pipe jacking construction in a soft foundation and silt environment, comprising a bell-and-spigot pipe and a steel blade foot assembly, wherein the steel blade foot assembly is arranged at one end of the bell-and-spigot pipe penetrating into the interior of the stratum, two groups of support brackets for supporting the lateral movement of the bell-and-spigot pipe are arranged on the front and rear sides of the stratum, a cast-in-place reaction wall is arranged on the side of the stratum away from the steel blade foot assembly, and a driving assembly for pushing the bell-and-spigot pipe into the interior of the stratum is arranged on the inner side of the cast-in-place reaction wall.

[0007] The above-mentioned ring-cutting steel blade foot device for pipe jacking construction in a soft foundation and silt environment is adopted. When it is necessary to set the direction of the bell-and-spigot pipe for jacking into the soil layer, a cast-in-place reaction wall is pre-set in the working pit of the stratum and a guide groove is excavated. A guide assembly and an extension frame are installed in the guide groove. During the jacking process of the bell-and-spigot pipe, it is ensured that the steel blade foot assembly at the end of the bell-and-spigot pipe cuts into the soil layer of the culvert. The bell-and-spigot pipe hoisted to the end of the inner tunnel of the working pit is guided by multiple groups of guide rollers of the support frame. Then, the protective plate and the bell-and-spigot pipe are pushed into the culvert by extending the oil cylinder to push the buffer pad. After the extended length of the telescopic end of the oil cylinder reaches the maximum stroke, the oil return cylinder guides the telescopic end to retract, and at the same time, the motor The work drives the screw to rotate, and the screw is used to drive the extension frame to move upward, and the first group of top plates at the top of the extension frame is moved between the telescopic end of the cylinder and the bell pipe. At this time, the cylinder returns to oil and extends again to realize the jacking action, and uses the top plate as a force transmission medium to realize the second bell pipe jacking action. After the cylinder is extended to the maximum stroke for the second time, the cylinder retracts and the extension frame continues to move upward until the second group of top plates is flush with the telescopic end of the cylinder. The above steps are operated, and multiple groups of stepped top plates are used as force transmission media in turn to realize the periodic jacking action of the bell pipe. After one group of bell pipes is completely jacked into the culvert, the next group of bell pipes are sent into the working pit through the lifting equipment to realize continuous jacking construction.

[0008] Preferably, the bell-and-spigot pipe is a prefabricated reinforced concrete pipe, an annular plug is provided at one end of the bell-and-spigot pipe close to the steel blade foot assembly, and a socket head for plugging in a mating plug is provided at the other end of the bell-and-spigot pipe.

[0009] Preferably, the steel blade foot assembly includes three groups of arc-shaped steel plates, which together form a ring clamped to the outer circumference of the socket, and channel steels extending along the length direction of the socket are fixed on both sides of the steel plates.

[0010] Preferably, a double row of reinforcing bolts are fixedly connected between the two groups of channel steels at the junction of adjacent steel plates, a sealing ring is provided at the junction between the outer side of the plug and the inner side of the steel plate, and a 45° blade bevel is provided at the front end of the outer side of the steel plate.

[0011] Preferably, a culvert for accommodating a bell-and-spigot pipe is laterally arranged in the middle of the stratum, a laterally extending guide groove is arranged on the stratum between the two groups of supporting frames, and a receiving groove for accommodating a cast-in-place reaction wall is arranged on the top surface of the stratum away from the culvert.

[0012] Preferably, the cast-in-place reaction wall is provided with an L-shaped reaction force dispersion frame pressed against the stratum on the side away from the bell pipe, and the inner side of the reaction force dispersion frame is provided with right-angled triangle reinforcement ribs.

[0013] Preferably, the drive assembly comprises a plurality of groups of oil cylinders which are longitudinally arranged and fixed on the cast-in-place reaction wall, and buffer pads are longitudinally fixed to the telescopic ends of the plurality of oil cylinders, and a protective plate is arranged between the buffer pad and the socket pipe, and the protective plate is a circular ring structure.

[0014] Preferably, a guide assembly is provided at the bottom of the guide groove, an extension frame is provided at the top of the guide assembly, the guide assembly comprises a C-shaped concrete bottom frame with an opening facing upward, a guide block is provided inside the concrete bottom frame, and two groups of cross bars are longitudinally and parallelly provided inside the concrete bottom frame and laterally penetrate the guide blocks, and the guide blocks are laterally slidably matched with the cross bars.

[0015] Preferably, a C-shaped motor frame with an opening facing downward is fixed on the top of the guide block, a motor is fixed inside the motor frame, a screw rod vertically passing through the motor frame is fixed to the top output end of the motor, the screw rod is threadedly matched with the extension frame, and two groups of vertical rods vertically penetrating into the extension frame to support the vertical sliding of the extension frame are symmetrically arranged on both sides of the screw rod.

[0016] Preferably, a plurality of groups of top plates distributed in a stepped manner are arranged on the top side of the extension frame, the lateral lengths of the plurality of top plates are equal and are not greater than the telescopic stroke of the oil cylinder, the support frame includes a transversely extending crossbeam, a plurality of groups of guide rollers pressed against the outer circumference of the socket pipe are evenly arranged on the top side of the crossbeam, the length direction of the guide rollers is tangent to the outer circumference of the socket pipe, and the guide rollers are rotatably matched with the crossbeam.

[0017] The beneficial effect is that the present invention arranges a multi-piece assembled steel blade foot at the end of the bell-and-spigot pipe, increases the supporting strength of the overall structure of the steel blade foot by cooperating with the arc-shaped steel plate and the inner channel steel, and reduces the contact area between the pipe wall at the end of the bell-and-spigot pipe and the soil layer, thereby reducing the pushing resistance during the jacking process, improving the construction efficiency, and is easy to install, overcoming the external force exerted on the end of the pipe during the jacking process, and ensuring the overall rigidity and stability of the pipe.

[0018] A set of stepped extension frames are added in the working pit of the stratum, and the extension frames are used instead of the assembled jacking irons in the existing jacking process as the force transmission mechanism, which solves the impact of repeated installation of jacking irons on construction efficiency, increases the stability of the cylinder's jacking action on the socket pipe, and avoids the risk of distortion and collapse when multiple sets of jacking irons are spliced ​​end to end during the jacking process, further improving construction safety and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a main structural diagram of the present invention;

[0021] Figure 2 It is a three-dimensional structural schematic diagram of the present invention;

[0022] Figure 3 It is a schematic diagram of the structural decomposition of the present invention;

[0023] Figure 4 is a front cross-sectional view of the present invention;

[0024] Figure 5 It is a schematic diagram of the structural disassembly of the steel blade foot assembly of the present invention;

[0025] Figure 6 It is a schematic diagram of the structural disassembly of the steel blade foot assembly of the present invention in another direction;

[0026] Figure 7 It is a left view structural diagram of the steel blade foot assembly of the present invention;

[0027] Figure 8 It is a three-dimensional structural schematic diagram of the guide assembly of the present invention;

[0028] Fig. 9 It is a three-dimensional structural schematic diagram of the support frame of the present invention.

[0029] The following are the descriptions of the reference numerals:

[0030] 1. Socket-and-spigot pipe; 101. Plug; 102. Sealing ring; 103. Socket head; 2. Stratum; 201. Culvert; 202. Guide groove; 203. Accommodation groove; 3. Steel blade foot assembly; 301. Steel plate; 301a. Blade foot groove; 302. Channel steel; 303. Reinforcement bolt; 4. Protective plate; 401. Flange; 5. Support frame; 501. Crossbeam; 502. Guide roller; 6. Cast-in-place reaction wall; 601. Reaction force dispersion frame; 602. Reinforcement rib; 7. Drive assembly; 701. Cylinder; 702. Buffer pad; 8. Extension frame; 801. Top plate; 9. Guide assembly; 901. Concrete bottom frame; 902. Cross bar; 903. Motor frame; 904. Motor; 905. Screw; 906. Vertical bar; 907. Guide block. DETAILED DESCRIPTION

[0031] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0032] See also Figure 1-Figure 9 As shown, the present invention provides a ring-cutting steel blade foot device for pipe jacking construction in a soft foundation silt environment, comprising a bell pipe 1 and a steel blade foot assembly 3. The steel blade foot assembly 3 is arranged at one end of the bell pipe 1 penetrating into the interior of a stratum 2. The steel blade foot assembly 3 serves as a soil cutting and feeding structure for the frontmost group of bell pipes 1, and is responsible for breaking the soil layer to guide the jacking of multiple groups of bell pipes 1 connected end to end at the rear side. Two groups of support brackets 5 for supporting the lateral movement of the bell pipes 1 are arranged on the front and rear sides of the stratum 2. The support brackets 5 are used to replace the slide plates in the existing jacking equipment to improve the convenience of movement of the bell pipes 1. A cast-in-place reaction wall 6 is arranged on the side of the stratum 2 away from the steel blade foot assembly 3. A driving assembly 7 for pushing the bell pipe 1 into the interior of the stratum 2 is arranged on the inner side of the cast-in-place reaction wall 6. The cast-in-place reaction wall 6 is used to support and fix the driving assembly 7.

[0033] As an optional embodiment, the bell-and-spigot pipe 1 is a reinforced concrete prefabricated pipe, and an annular plug 101 is provided at one end of the bell-and-spigot pipe 1 close to the steel blade foot assembly 3, and a socket 103 for plugging and matching the plug 101 is provided at the other end of the bell-and-spigot pipe 1. The plug 101 is plugged and matched with the socket 103 to facilitate the connection of multiple groups of bell-and-spigot pipes 1 connected end to end and then pushed into the culvert 201 in sequence. The steel blade foot assembly 3 includes three groups of arc-shaped steel plates 301, and the three groups of steel plates 301 together form a circular ring clamped to the outer circumference of the plug, and channel steels 302 extending along the length direction of the bell-and-spigot pipe 1 are fixed on both sides of the steel plates 301. Adjacent steel plates 30 A double row of reinforcing bolts 303 are fixedly connected between the two groups of channel steels 302 at the joint 1, and the adjacent and tightly pressed channel steels 302 are locked and connected by the reinforcing bolts 303 to realize the assembly and combination process of the three groups of steel plates 301. A sealing ring 102 is sleeved at the joint between the outer side of the plug 101 and the inner side of the steel plate 301. The sealing ring 102 increases the sealing performance of the joint between the steel blade foot assembly 3 and the socket pipe 1. A 45° blade foot groove 301a is arranged at the front end of the outer side of the steel plate 301. The outer side of the steel plate 301 is used as the blade foot groove 301a, thereby increasing the sharp effect of the outer edge of the steel plate 301 on cutting and breaking the internal soil layer of the culvert 201.

[0034] A culvert 201 for accommodating the bell-and-spigot pipe 1 is transversely arranged in the middle of the stratum 2, a transversely extending guide groove 202 is arranged on the stratum 2 between the two groups of support brackets 5, and a receiving groove 203 for accommodating the cast-in-place reaction wall 6 is arranged on the top surface of the stratum 2 away from the culvert 201. The cast-in-place reaction wall 6 is cast in-situ inside and above the receiving groove 203 through formwork support, and an L-shaped reaction force dispersion frame 601 is arranged on the side of the cast-in-place reaction wall 6 away from the bell-and-spigot pipe 1, which is pressed against the stratum 2, and a right-angled triangle reinforcement rib 602 is arranged on the inner side of the reaction force dispersion frame 601. The driving assembly 7 includes a plurality of groups of oil cylinders 701 arranged longitudinally and fixed on the cast-in-situ reaction wall 6. A buffer pad 702 is longitudinally fixed to the telescopic end of multiple groups of oil cylinders 701, and a protective plate 4 is arranged between the buffer pad 702 and the bell-and-spigot pipe 1. The protective plate 4 is a circular ring structure, and a flange 401 extending into the inside of the bell-and-spigot pipe 1 is arranged on the inner side of the protective plate 4, so as to increase the connection stability between the protective plate 4 and the bell-and-spigot pipe 1 through the flange 401. The protective plate 4 and the buffer pad 702 are used to increase the stability of the oil cylinder 701 pushing the bell-and-spigot pipe 1. A guide assembly 9 is arranged at the bottom of the guide groove 202, and an extension frame 8 is arranged at the top of the guide assembly 9. The guide assembly 9 includes a C-shaped concrete bottom frame 901 with an opening facing upward, and the concrete bottom frame 901 is cast on the guide groove 202. Into the groove, a guide block 907 is arranged inside the concrete bottom frame 901, and two groups of cross bars 902 are arranged longitudinally and parallelly inside the concrete bottom frame 901, which penetrate the guide block 907 laterally. The guide block 907 slides with the cross bar 902 laterally, and the guide block 907 slides laterally through the cross bar 902. A C-shaped motor frame 903 with an opening facing downward is fixed on the top of the guide block 907. A motor 904 is fixed inside the motor frame 903. A screw 905 that vertically penetrates the motor frame 903 is fixed at the top output end of the motor 904. The screw 905 is threadedly matched with the extension frame 8. Two groups of vertically penetrating screws are symmetrically arranged on both sides of the screw 905. The interior of the extension frame 8 is provided with a vertical rod 906 for supporting the vertical sliding of the extension frame 8. A plurality of groups of top plates 801 distributed in a stepped manner are arranged on the top side of the extension frame 8. The lateral lengths of the plurality of top plates 801 are equal and are not greater than the telescopic stroke of the oil cylinder 701. The support frame 5 includes a transversely extending crossbeam 501. A plurality of groups of guide rollers 502 pressed against the outer circumference of the bell-and-spigot 1 are evenly arranged laterally on the top side of the crossbeam 501. The guide rollers 502 are tangent to the outer circumference of the bell-and-spigot 1 in length direction, and the guide rollers 502 are rotatably matched with the crossbeam 501. The guide rollers 502 are used to support the lateral movement of the bell-and-spigot 1 to increase the smoothness and stability of the bell-and-spigot 1 in the process of pressing the soil layer laterally.

[0035] By adopting the above structure, when it is necessary to set the direction of the bell-and-spigot pipe 1 to be pushed into the soil layer, a cast-in-place reaction wall 6 is pre-set in the working pit of the stratum 2 and a guide groove 202 is excavated. A guide assembly 9 and an extension frame 8 are installed in the guide groove 202. During the pushing process of the bell-and-spigot pipe 1, it is ensured that the steel blade foot assembly 3 at the end of the bell-and-spigot pipe 1 cuts into the soil layer of the culvert 201. The bell-and-spigot pipe 1 hoisted to the end of the culvert 201 in the working pit is guided by multiple groups of guide rollers 502 of the support frame 5. Then, the oil cylinder 701 is extended to push the buffer pad 702 to push the protective plate 4 and the bell-and-spigot pipe 1 into the culvert 201. After the extension length of the telescopic end of the oil cylinder 701 reaches the maximum stroke, the oil cylinder 701 returns oil to guide the telescopic end to retract, and at the same time, the motor 904 works to drive the screw 905 Rotate and use the screw 905 to drive the extension frame 8 to move upward, and move the first group of top plates 801 at the top of the extension frame 8 to between the telescopic end of the cylinder 701 and the bell-and-spigot pipe 1. At this time, the cylinder 701 returns to oil and extends again to realize the jacking action, so as to use the top plate 801 as a force transmission medium to realize the second jacking action of the bell-and-spigot pipe 1. After the cylinder 701 is extended to the maximum stroke for the second time, the cylinder 701 retracts and the extension frame 8 continues to move upward until the second group of top plates 801 is flush with the telescopic end of the cylinder 701. Operate in the above steps, and use multiple groups of stepped top plates 801 as force transmission media in turn to realize the periodic jacking action of the bell-and-spigot pipe 1. After one group of bell-and-spigot pipes 1 is completely jacked into the culvert 201, the next group of bell-and-spigot pipes 1 are sent into the working pit through the lifting equipment to realize continuous jacking construction.

[0036] By arranging a multi-piece assembled steel blade foot at the end of the bell-and-spigot pipe 1, the supporting strength of the overall structure of the steel blade foot is increased by cooperating with the arc-shaped steel plate 301 and the inner channel steel 302, and the contact area between the pipe wall at the end of the bell-and-spigot pipe 1 and the soil layer is reduced, thereby reducing the jacking resistance during the jacking process, improving the construction efficiency, and making the installation simple, overcoming the external force on the end of the pipeline during the jacking process, and ensuring the overall rigidity and stability of the pipeline.

[0037] A set of extension frames 8 with stepped structures are added in the working pit of the formation 2. The extension frames 8 are used to replace the assembled jacking irons in the existing jacking process as the force transmission mechanism, which solves the influence of repeated installation of jacking irons on the construction efficiency, increases the stability of the jacking action of the cylinder 701 on the socket pipe 1, avoids the risk of distortion and collapse when multiple sets of jacking irons are spliced ​​end to end during the jacking process, and further improves the construction safety and efficiency.

[0038] The applicant, China Water Resources and Hydropower Fourth Engineering Bureau Co., Ltd., implemented the structure of the present invention during the construction of the rainwater and sewage pipeline project on No. 39 Road, Ganquanbao Industrial Park, Midong District, Urumqi. The rainwater and sewage pipeline was designed to pass through the D1000*2 source water pipeline of Xinjiang Guoneng Chemical Plant under K1+787 (made of fiberglass, with a clear distance of 1.5 meters between pipes and a wall thickness of 0.12m). The thickness of the soil covering the source water pipeline is about 2.1m. The site is Class II non-self-weight collapsible and has groundwater exposure. D1200 reinforced concrete (wall thickness 120mm) jacking pipe is used to pass through the source water pipeline, and light well point dewatering is arranged before the jacking construction. The dewatering depth is greater than 0.5m below the bottom of the well to ensure that the soil covering around the source water pipeline is stable during the jacking operation. The area where the jacking pipeline passes through is in soft foundation silt below the groundwater level. During the implementation process, the stratum is prone to uplift and subsidence, causing the source water pipeline to deform and be damaged, resulting in extremely bad adverse effects and great economic losses. Therefore, providing effective technical measures during the jacking operation is the key to ensuring stratum stability and increasing the jacking speed.

[0039] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A ring-cutting steel blade foot device for pipe jacking construction in a soft foundation silt environment, characterized in that: It comprises a bell-and-spigot pipe (1) and a steel blade foot assembly (3), wherein the steel blade foot assembly (3) is arranged at one end of the bell-and-spigot pipe (1) penetrating into the interior of the stratum (2), two groups of support brackets (5) for supporting the lateral movement of the bell-and-spigot pipe (1) are arranged on the front and rear sides of the stratum (2), a cast-in-place reaction wall (6) is arranged on the side of the stratum (2) away from the steel blade foot assembly (3), and a driving assembly (7) for pushing the bell-and-spigot pipe (1) into the interior of the stratum (2) is arranged on the inner side of the cast-in-place reaction wall (6); A culvert (201) for accommodating a bell-and-spigot pipe (1) is transversely arranged in the middle of the stratum (2), a transversely extending guide groove (202) is arranged on the stratum (2) between the two groups of support frames (5), and a receiving groove (203) for accommodating a cast-in-place reaction wall (6) is arranged on the top surface of the stratum (2) away from the culvert (201); The cast-in-place reaction wall (6) is provided with an L-shaped reaction dispersion frame (601) which is pressed against the stratum (2) on the side away from the bell-and-spigot pipe (1), and a right-angled triangle reinforcement rib (602) is provided on the inner side of the reaction dispersion frame (601); The driving assembly (7) comprises a plurality of groups of oil cylinders (701) which are longitudinally arranged and fixed to the cast-in-place reaction wall (6); buffer pads (702) are longitudinally fixed to the telescopic ends of the plurality of groups of oil cylinders (701); a protective plate (4) is provided between the buffer pad (702) and the bell-and-spigot pipe (1); and the protective plate (4) is a circular ring structure; A guide assembly (9) is arranged at the bottom of the guide groove (202), an extension frame (8) is arranged at the top of the guide assembly (9), the guide assembly (9) comprises a C-shaped concrete bottom frame (901) with an opening facing upward, a guide block (907) is arranged inside the concrete bottom frame (901), and two groups of cross bars (902) are arranged longitudinally and parallel inside the concrete bottom frame (901) and laterally penetrate the guide blocks (907), and the guide blocks (907) and the cross bars (902) are laterally slidably matched; A C-shaped motor frame (903) with an opening facing downward is fixed on the top of the guide block (907), a motor (904) is fixed inside the motor frame (903), a screw rod (905) vertically passing through the motor frame (903) is fixed to the top output end of the motor (904), the screw rod (905) is threadedly engaged with the extension frame (8), and two groups of vertical rods (906) vertically passing through the extension frame (8) to support the vertical sliding of the extension frame (8) are symmetrically arranged on both sides of the screw rod (905); The top side of the extension frame (8) is provided with a plurality of groups of top plates (801) distributed in a stepped manner, the plurality of groups of top plates (801) have equal transverse lengths and are not greater than the telescopic stroke of the oil cylinder (701), the support frame (5) comprises a transversely extending crossbeam (501), the top side of the crossbeam (501) is evenly provided with a plurality of guide rollers (502) pressed against the outer circumference of the bell-and-spigot (1), the length direction of the guide rollers (502) is tangent to the outer circumference of the bell-and-spigot (1), and the guide rollers (502) are rotatably matched with the crossbeam (501).

2. According to claim 1, a ring-cutting steel blade foot device for pipe jacking construction in a soft foundation silt environment, characterized in that: The bell-and-spigot pipe (1) is a reinforced concrete prefabricated pipe, one end of the bell-and-spigot pipe (1) close to the steel blade foot assembly (3) is provided with an annular plug (101), and the other end of the bell-and-spigot pipe (1) is provided with a socket (103) for plugging into the mating plug (101).

3. According to claim 2, a ring-cutting steel blade foot device for pipe jacking construction in a soft foundation silt environment, characterized in that: The steel blade foot assembly (3) comprises three groups of arc-shaped steel plates (301), which together form a circular ring clamped to the outer circumference of the spigot, and channel steels (302) extending along the length direction of the socket pipe (1) are fixed on both sides of the steel plates (301).

4. According to claim 3, a ring-cutting steel blade foot device for pipe jacking construction in a soft foundation silt environment, characterized in that: A double row of reinforcing bolts (303) are fixedly connected between two groups of channel steels (302) at the junction of adjacent steel plates (301), a sealing ring (102) is sleeved at the junction between the outer side of the plug (101) and the inner side of the steel plate (301), and a 45° blade bevel (301a) is provided at the front end of the outer side of the steel plate (301).

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