A pipe jacking construction method with external ring cutting and jacking

Abstract

The present invention discloses a pipe jacking construction method with external ring cutting, including a bell-and-spigot pipe and a steel blade foot assembly fixed to one end of the bell-and-spigot pipe penetrating into the stratum, a working pit for accommodating the bell-and-spigot pipe is arranged on the stratum, a cast-in-place reaction wall is arranged on the side of the working pit away from the steel blade foot assembly, and a driving assembly for pushing the bell-and-spigot pipe into the stratum is fixed on the cast-in-place reaction wall. The beneficial effect is that the present invention arranges a containing frame for accommodating multiple groups of top iron plates above the oil cylinder as a jacking mechanism, and the top iron plates stacked in the containing frame automatically fall down while the oil cylinder returns and contracts, so that there is no need for manual handling to add top iron, and the cumbersome operation of the existing top iron that needs to be fixed to avoid its collapse is improved, and the influence of manual repeated installation of top iron on construction efficiency is avoided, the operation is simple, and there is no need for manual approach to add top iron during the pipe jacking process, so it is safer to use and the efficiency of pipe jacking is improved.

Description

Technical Field

[0001] The invention relates to the field of pipe jacking construction, and in particular to a pipe jacking construction method with external ring cutting and jacking. Background Art

[0002] Pipe jacking construction is a trenchless construction method and a pipeline burial construction technology that does not involve excavation or less excavation. Pipe jacking construction is to use the jacking force generated by the jacking equipment in the working well to overcome the friction between the pipeline and the surrounding soil, and jack the pipeline into the soil according to the designed slope. After one section of the pipe is jacked 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 and the pipeline and relay rooms to push the tool pipe from the working pit through the soil layer to the receiving pit for lifting. The pipeline is buried between the two pits. The jacking iron is a device for transmitting and dispersing the jacking force. It relies on manual handling during use. The existing pipe jacking construction method is to fix the jacking iron at the jack piston as a force transmission structure. After the jacking iron is installed, the oil pump is started to feed oil. The piston extends a working stroke and then returns the oil. After the piston retracts, it is manually handled to add jacking irons. The adjacent jacking irons need to be fixed to avoid the jacking irons from collapsing under pressure. The operation process is cumbersome, which affects the efficiency of pipe jacking construction. Summary of the invention

[0003] The purpose of the present invention is to provide a pipe jacking construction method with external ring cutting in order to solve the above-mentioned problems, which is safer to use and improves the efficiency of pipe jacking, as described below.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides a pipe jacking construction method of external ring cutting jacking, and the pipe jacking construction method comprises the following steps:

[0006] Step (1): designing a pipe jacking construction device, the pipe jacking construction device comprising a bell-and-spigot pipe and a steel blade foot assembly fixed to one end of the bell-and-spigot pipe penetrating into the ground, a working pit for accommodating the bell-and-spigot pipe being provided on the ground, a cast-in-place reaction wall being provided on the side of the working pit away from the steel blade foot assembly, a driving assembly for pushing the bell-and-spigot pipe into the ground being fixed on the cast-in-place reaction wall;

[0007] A circular plug is provided at one end of the bell pipe near the steel blade foot assembly, and a socket is provided at the other end of the bell pipe for plugging in and cooperating with the adjacent bell pipe plug. The steel blade foot assembly includes three groups of arc-shaped steel plates that together form a circular ring-shaped annular cutting blade, and mutually parallel channel steels are fixed on the inner sides of two adjacent groups of steel plates, and double rows of reinforcement bolts are fixedly connected between the two adjacent groups of channel steels, and sealing rings that are clamped tightly on the outer sides of the plugs are provided on the inner sides of the three groups of steel plates.

[0008] Two groups of C-shaped guide rails with openings facing each other are arranged on the front and rear sides of the working pit, a lower plate groove is arranged on the top of the guide rail close to the driving assembly side, and an upper plate groove is arranged on the top of the guide rail close to the steel blade foot assembly side, a containing frame is fixed inside the working pit above the lower plate groove, the containing frame is a through structure vertically connected to the lower plate groove, and multiple groups of top iron plates are vertically stacked inside the containing frame.

[0009] The driving assembly includes several groups of oil cylinders arranged longitudinally and fixed on the cast-in-place reaction wall. The telescopic ends of the several groups of oil cylinders are longitudinally connected with pressure plates that push the socket pipes to move. The top side of the pressure plate extends away from the socket pipe to form a limit plate that supports the top iron plate.

[0010] Step (2): Dig a starting shaft in the working pit, adopt open-cut method, excavate in sections, support in sections, use reinforced concrete to construct the reinforced concrete bottom plate on all sides of the retaining wall, and then construct a cast-in-place reaction wall. Install two sets of parallel guide rails in the working pit according to the actual three-dimensional spatial position, and install a containing frame in the working pit above the upper plate groove of the guide rail, and stack multiple sets of top iron plates in the containing frame.

[0011] Step (3): Install a cylinder as a propulsion jack on the cast-in-place reaction wall, and use the limit plate on the pressure plate at the telescopic end of the cylinder as a support structure to prevent the top iron plate from falling. Then, hoist the prefabricated bell and spigot pipe into the working pit, and use the telescopic end of the cylinder to extend and then push the bell and spigot pipe through the pressure plate to extend into the soil layer under the guiding cutting action of the steel blade foot assembly at its end.

[0012] Step (4): After the oil cylinder is extended to the maximum stroke, the telescopic end of the oil cylinder contracts, and the oil cylinder drives the pressure plate and the limit plate to move away from the socket pipe until the limit plate moves to a state of separation from the top iron plate in the accommodating frame. At this time, the support effect on the top iron plate is released, and multiple groups of vertically stacked top iron plates fall downward at the same time. The bottom group of top iron plates falls into the two groups of guide rails along the lower plate groove. This group of top iron plates is located between the telescopic end of the oil cylinder and the socket pipe. At this time, the oil cylinder in the contracted state is extended again to use the fallen group of top iron plates as an extended force-bearing component, thereby completing the second pipe jacking action.

[0013] Step (5): When the second jacking action of the bell-and-spigot pipe is completed, the oil cylinder reaches the maximum extension stroke again. At this time, the oil cylinder contracts to drive the pressure plate and the limit plate to retreat, and the lowest set of jacking iron plates in the accommodating frame continues to fall into the guide rail along the lower plate groove. The jacking iron plates are automatically dropped during the extension and retraction of the oil cylinder, thereby continuously adding to the length of the jacking irons, so that multiple sets of jacking irons fall down in sequence and are connected end to end to transmit the jacking power until the bell-and-spigot pipe is completely pushed into the soil layer. The staff takes out the multiple sets of jacking iron plates in sequence along the upper plate groove to complete the jacking process of a section of the bell-and-spigot pipe.

[0014] By adopting the above technical scheme, when the bell-and-spigot pipe is pushed into the soil layer, a steel blade foot is first installed at the end of the bell-and-spigot pipe, and three groups of steel plates are spliced ​​and pressed against the outer circumference of the plug pipe of the bell-and-spigot pipe through a pair of channel steels, and the adjacent and pressed channel steels are locked and connected by reinforcing bolts to realize the assembly and combination process of the three groups of steel plates; the sealing ring sleeved at the junction of the outer side of the plug and the inner side of the steel plate increases the sealing of the junction between the steel blade foot assembly and the bell-and-spigot pipe, so that the outer side of the steel plate is used as the pushing blade of the steel blade foot, and then it is convenient to cut and break the soil layer inside the culvert through the outer edge of the steel plate, so as to guide the bell-and-spigot pipe to be pushed into the soil layer.

[0015] As an important design of this case, in step (1), the double-row reinforcement bolts are M12 bolts, the number of double-row reinforcement bolts is eight groups and they are evenly distributed in two columns laterally, and a 45° blade bevel is provided at the front end of the outer side of the steel plate.

[0016] The above structure is adopted, and the 45° blade foot groove at the front end of the outer side of the steel plate is utilized. The blade foot groove of the steel blade foot assembly serves as the soil cutting and feeding structure of the frontmost group of socket pipes. It is responsible for breaking the soil layer to guide the synchronous jacking function of the end-to-end connection of multiple groups of socket pipes at the rear side. During the jacking operation, the pipe wall pushing resistance and friction resistance of the reinforced concrete socket pipe are reduced, the construction efficiency is improved, and it has better applicability, economy and operability.

[0017] Preferably, in step (1), the cast-in-place reaction wall is provided with an L-shaped reaction force dispersion frame pressed against the bottom of the working pit on the side away from the bell-and-spigot pipe, and the inner side of the reaction force dispersion frame is provided with a right-angled triangular reinforcement rib;

[0018] Two groups of mounting frames are fixed on the front and rear sides of the top of the supporting frame. The top of the mounting frame extends toward the inner wall of the working pit, and mounting grooves for supporting the mounting frame are arranged on the front and rear sides of the top of the working pit.

[0019] Preferably, in step (1), the thickness of the top iron plate is greater than the vertical height of the pressure plate, and sliding grooves for supporting the vertical sliding of the top iron plate are arranged on the front and rear sides of the interior of the accommodating frame, and the spacing between the two groups of the sliding grooves is equal to the longitudinal width of the opening of the lower plate groove.

[0020] Preferably, in step (2), two groups of support brackets for supporting the bell-and-spigot pipes are symmetrically arranged on the front and rear sides of the working pit below the guide rail, and the support brackets include a crossbeam transversely fixed to the inner wall of the working pit, and the crossbeam is a C-shaped frame with an opening facing upward, and a plurality of rotating seats are evenly distributed on the top of the crossbeam along its length, and guide rollers are rotatably engaged on the rotating seats, and the outer sides of the guide rollers are tightly pressed against the outer circumference of the bell-and-spigot pipes.

[0021] Preferably, both ends of the guide rail are fixed to the inner wall of the working pit and the cast-in-place reaction wall by expansion bolts respectively, and the opening widths of the upper plate groove and the lower plate groove are both greater than the width of the top iron plate.

[0022] Preferably, in step (2), the pressure plate and the limit plate are both made of Q345B steel and are fixed by welding, and the limit plate and the pressure plate are fixed to the output end of the cylinder by bolts.

[0023] Preferably, the steel plate is Q345B steel with a thickness of 5 mm, the outer side of the steel plate is flush with the outer circumference of the socket pipe, the yield strength of the channel steel is ≥345N / mm², the tensile strength is 470~630Mpa, and the impact energy is ≥34kJ / m².

[0024] Preferably, in step (3), the bell-and-spigot pipe is a prefabricated reinforced concrete pipe structure, and the wall thickness of the bell-and-spigot pipe is 120 mm, and the outer circumferential side of the steel plate of the steel blade foot assembly is flush with the outer side wall of the bell-and-spigot pipe.

[0025] In summary, the beneficial effects of the present invention are as follows: a containing frame for accommodating multiple groups of top iron plates is arranged above the oil cylinder serving as a jacking mechanism, and the top iron plates stacked in the containing frame automatically fall down as the oil cylinder returns and contracts, so that there is no need for manual handling to add top irons, and the cumbersome operation of the existing top irons that need to be fixed to avoid their collapse is improved. The operation is simple, and there is no need for manual approach to add top irons during the jacking process of the pipe jacking. The use is safer and the jacking efficiency of the pipe jacking is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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.

[0027] Figure 1 It is a top view of the structure of the present invention;

[0028] Figure 2 It is a three-dimensional structural schematic diagram of the present invention;

[0029] Figure 3 It is a schematic diagram of the structural decomposition of the present invention;

[0030] Figure 4 It is a schematic diagram of the partial structure splitting of the present invention;

[0031] Figure 5 It is a schematic diagram of the structure disassembly of the bell-and-spigot pipe of the present invention;

[0032] Figure 6 It is a schematic diagram of the structural disassembly of the steel blade foot assembly of the present invention;

[0033] Figure 7 It is a three-dimensional structural schematic diagram of the driving assembly of the present invention;

[0034] Figure 8 It is a three-dimensional structural schematic diagram of the support frame of the present invention.

[0035] The following are the descriptions of the reference numerals:

[0036] 1. Stratum; 101. Working pit; 102. Mounting groove; 2. Socket-and-spigot pipe; 201. Plug; 202. Socket head; 3. Steel blade foot assembly; 301. Steel plate; 302. Sealing ring; 303. Channel steel; 303a. Reinforcement bolt; 4. Cast-in-place reaction wall; 401. Reaction dispersion frame; 5. Driving assembly; 501. Oil cylinder; 502. Pressure plate; 502a. Limiting plate; 6. Accommodating frame; 601. Top iron plate; 602. Mounting frame; 7. Guide rail; 701. Lower plate groove; 702. Upper plate groove; 8. Support frame; 801. Crossbeam; 802. Rotating seat; 803. Guide roller. DETAILED DESCRIPTION

[0037] 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.

[0038] See also Figure 1-Figure 8 As shown, the present invention provides a pipe jacking construction method with external ring cutting and jacking, and the pipe jacking construction method comprises the following steps:

[0039] Step (1): Design a pipe jacking construction device, which includes a bell-and-spigot pipe and a steel blade foot assembly fixed to one end of the bell-and-spigot pipe that penetrates into the ground. The steel blade foot assembly is used to break the soil layer and guide the bell-and-spigot pipe to be pushed into the soil layer. A working pit for accommodating the bell-and-spigot pipe is provided on the ground layer. A cast-in-place reaction wall is provided on the side of the working pit away from the steel blade foot assembly. A driving assembly for pushing the bell-and-spigot pipe into the ground layer is fixed on the cast-in-place reaction wall.

[0040] A circular plug is provided at one end of the bell-and-spigot pipe near the steel blade foot assembly, and a socket is provided at the other end of the bell-and-spigot pipe for plugging and matching with the adjacent bell-and-spigot pipe plug, so that the plug and the socket can be plugged and matched to achieve end-to-end connection of multiple groups of bell-and-spigot pipes, thereby jacking into the soil layer to complete the jacking construction. The steel blade foot assembly includes three groups of arc-shaped steel plates that together form a circular ring-shaped annular cutting blade, and the inner sides of two adjacent groups of steel plates are fixed with mutually parallel channel steels, and double rows of reinforcement bolts are fixedly connected between the two adjacent groups of channel steels. The inner sides of the three groups of steel plates are provided with sealing rings that are clamped on the outer sides of the plugs, and the sealing rings are used to increase the sealing effect of the connection between the steel blade foot assembly and the bell-and-spigot pipe.

[0041] Two groups of C-shaped guide rails with openings facing each other are arranged on the front and rear sides of the working pit, a lower plate groove is arranged on the top of the guide rail close to the driving assembly side, and an upper plate groove is arranged on the top of the guide rail close to the steel blade foot assembly side, a containing frame is fixed inside the working pit above the lower plate groove, the containing frame is a through structure vertically connected to the lower plate groove, a plurality of groups of top iron plates are vertically stacked inside the containing frame, the top iron plates are used to be arranged between the telescopic end of the oil cylinder and the socket pipe, the top iron plates serve as a force transmission mechanism for transmitting the power of the oil cylinder to push the socket pipe.

[0042] The driving assembly includes several groups of oil cylinders arranged longitudinally and fixed on the cast-in-place reaction wall. The telescopic ends of the several groups of oil cylinders are longitudinally connected with pressure plates that push the socket pipes to move. The top side of the pressure plate extends away from the socket pipe to form a limit plate that supports the top iron plate. The top iron plate in the accommodating frame is supported by the limit plate.

[0043] Step (2): dig a starting shaft in the working pit, adopt an open-cut method, excavate in sections, and support in sections to ensure the construction safety of the working pit. The surrounding retaining walls are constructed with reinforced concrete. The reinforced concrete bottom plate is then constructed, and a cast-in-place reaction wall is then constructed. Two sets of parallel guide rails are installed in the working pit according to the actual three-dimensional spatial position, and a containing frame is installed in the working pit above the upper plate groove of the guide rail. Multiple sets of top iron plates are stacked in the containing frame, and the containing frame is used as a storage structure to support the top iron plates.

[0044] Step (3): Install a cylinder as a propulsion jack on the cast-in-place reaction wall, and use the limit plate on the pressure plate at the telescopic end of the cylinder as a support structure to prevent the top iron plate from falling. Then, hoist the prefabricated bell and spigot pipe into the working pit, and use the telescopic end of the cylinder to extend and then push the bell and spigot pipe through the pressure plate to extend into the soil layer under the guiding cutting action of the steel blade foot assembly at its end.

[0045] Step (4): After the oil cylinder is extended to the maximum stroke, the telescopic end of the oil cylinder contracts, and the oil cylinder drives the pressure plate and the limit plate to move away from the socket pipe until the limit plate moves to a state of separation from the top iron plate in the accommodating frame. At this time, the support effect on the top iron plate is released, and multiple groups of vertically stacked top iron plates fall downward at the same time. The bottom group of top iron plates falls into the two groups of guide rails along the lower plate groove. This group of top iron plates is located between the telescopic end of the oil cylinder and the socket pipe. At this time, the oil cylinder in the contracted state is extended again to use the fallen group of top iron plates as an extended force-bearing component, thereby completing the second pipe jacking action.

[0046] Step (5): When the second jacking action of the bell-and-spigot pipe is completed, the oil cylinder reaches the maximum extension stroke again. At this time, the oil cylinder contracts to drive the pressure plate and the limit plate to retreat, and the lowest set of jacking iron plates in the accommodating frame continues to fall into the guide rail along the lower plate groove. The jacking iron plates are automatically dropped during the extension and retraction of the oil cylinder, thereby continuously adding to the length of the jacking irons, so that multiple sets of jacking irons fall down in sequence and are connected end to end to transmit the jacking power until the bell-and-spigot pipe is completely pushed into the soil layer. The staff takes out the multiple sets of jacking iron plates in sequence along the upper plate groove to complete the jacking process of a section of the bell-and-spigot pipe.

[0047] By adopting the above technical scheme, when the bell-and-spigot pipe is pushed into the soil layer, a steel blade foot is first installed at the end of the bell-and-spigot pipe, and three groups of steel plates are spliced ​​and pressed against the outer circumference of the plug of the bell-and-spigot pipe through a pair of channel steels, and the adjacent and pressed channel steels are locked and connected by reinforcing bolts to realize the assembly and combination process of the three groups of steel plates; the sealing ring sleeved at the junction of the outer side of the plug and the inner side of the steel plate increases the sealing of the junction between the steel blade foot assembly and the bell-and-spigot pipe, so that the outer side of the steel plate is used as the pushing blade of the steel blade foot, and then it is convenient to cut and break the soil layer inside the culvert through the outer edge of the steel plate, so as to guide the bell-and-spigot pipe to be pushed into the soil layer, reduce the friction of the bell-and-spigot pipe pushed into the soil layer, and thus improve the jacking efficiency.

[0048] As an important design of this case, the double-row reinforcement bolts in step (1) are M12 bolts, the number of double-row reinforcement bolts is eight groups and they are evenly distributed in two columns horizontally, and a 45° blade bevel is provided at the front end of the outer side of the steel plate.

[0049] The above structure is adopted, and the 45° blade foot groove at the front end of the outer side of the steel plate is utilized. The blade foot groove of the steel blade foot assembly serves as the soil cutting and feeding structure of the frontmost group of socket pipes. It is responsible for breaking the soil layer to guide the synchronous jacking function of the end-to-end connection of multiple groups of socket pipes at the rear side. During the jacking operation, the pipe wall pushing resistance and friction resistance of the reinforced concrete socket pipe are reduced, the construction efficiency is improved, and it has better applicability, economy and operability.

[0050] As a preferred technical solution in this case, the cast-in-place reaction wall in step (1) is provided with an L-shaped reaction force dispersion frame pressed against the bottom side of the working pit on the side away from the socket pipe, and the inner side of the reaction force dispersion frame is provided with a right-angled triangle reinforcement rib. The cast-in-place reaction wall is used in conjunction with the reaction force dispersion frame to support the oil cylinder, thereby improving the stability of the oil cylinder pushing into the socket pipe; two sets of mounting frames are fixed on the front and rear sides of the top of the support frame, the top of the mounting frame extends toward the inner side wall of the working pit, and the front and rear sides of the top of the working pit are provided with mounting grooves for supporting the mounting frames. The thickness of the top iron plate is greater than the vertical height of the pressure plate. After a group of top iron plates falls into the guide rail along the lower plate groove, the pressure plate is used to push the group of top iron plates to support the socket pipe. At this time, it is ensured that the limit plate on the top side of the pressure plate can continue to support several groups of top iron plates above. The front and rear sides of the interior of the accommodating frame are both provided with sliding grooves for supporting the vertical sliding of the top iron plates. The spacing between the two groups of sliding grooves is equal to the longitudinal width of the opening of the lower plate groove, ensuring that the top iron plate can move down along the sliding groove and fall into the guide rail along the lower plate groove.

[0051] In step (2), two groups of support brackets for supporting the bell-and-spigot pipes are symmetrically arranged on the front and rear sides of the working pit below the guide rail, the support brackets include a crossbeam transversely fixed to the inner wall of the working pit, the crossbeam is a C-shaped frame with an opening facing upward, and a plurality of rotating seats are evenly distributed on the top of the crossbeam along its length direction, and guide rollers are rotatably matched on the rotating seats, and the outer sides of the guide rollers are tightly abutted against the outer circumferential sides of the bell-and-spigot pipes, thereby facilitating the lateral movement of the bell-and-spigot pipes by supporting the guide rollers on the crossbeams, thereby improving the stability of the bell-and-spigot pipes being pushed into the soil layer, and the two ends of the guide rails are respectively fixed to the inner wall of the working pit and the cast-in-place reaction wall by expansion bolts, and the opening widths of the upper plate groove and the lower plate groove are both larger than the width of the top iron plate, ensuring that the top iron plate can be smoothly taken and placed through the upper plate groove and the lower plate groove. In step (2), the pressure plate and the limit plate are both made of Q345B steel and are fixed by welding to ensure the structural strength of the pressure plate and the limit plate, and the limit plate and the pressure plate are fixed to the output end of the cylinder by bolts. The steel plate is Q345B steel with a thickness of 5 mm. The outer side of the steel plate is flush with the outer circumferential side of the socket pipe. The yield strength of the channel steel is ≥345N / mm², the tensile strength is 470~630Mpa, and the impact energy is ≥34kJ / m², ensuring that the structural strength of the channel steel can support the socket pipe to be pushed into the soil layer, overcome the external force on the end of the pipe during the pipe pushing process, and ensure the overall rigidity and stability of the pipe.

[0052] Furthermore, in step (3), the bell-and-spigot pipe is a prefabricated reinforced concrete pipe structure, and the wall thickness of the bell-and-spigot pipe is 120 mm, and the outer circumferential side of the steel plate of the steel blade foot assembly is flush with the outer side wall of the bell-and-spigot pipe.

[0053] A containing frame for accommodating multiple groups of top iron plates is provided above the oil cylinder serving as a jacking mechanism. The top iron plates stacked in the containing frame automatically drop down as the oil cylinder returns and contracts, thereby eliminating the need for manual handling to add top irons. This improves the cumbersome operation of the existing top irons, which need to be fixed to avoid their collapse, and avoids the influence of manual repeated installation of top irons on construction efficiency. The operation is simple, and there is no need for manual labor to add top irons during the jacking process. This makes it safer to use and improves the jacking efficiency of the jacking pipe.

[0054] 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 pipe jacking construction method with external ring cutting and jacking, characterized in that: The steps include: Step (1): designing a pipe jacking construction device, the pipe jacking construction device comprising a bell-and-spigot pipe and a steel blade foot assembly fixed to one end of the bell-and-spigot pipe penetrating into the ground, a working pit for accommodating the bell-and-spigot pipe being provided on the ground, a cast-in-place reaction wall being provided on the side of the working pit away from the steel blade foot assembly, a driving assembly for pushing the bell-and-spigot pipe into the ground being fixed on the cast-in-place reaction wall; In step (1), a circular plug is provided at one end of the bell-and-spigot pipe near the steel blade foot assembly, and a socket head is provided at the other end of the bell-and-spigot pipe for plugging and matching the circular plug of the adjacent bell-and-spigot pipe. The steel blade foot assembly includes three groups of arc-shaped steel plates that together form a circular annular cutting blade, and mutually parallel channel steels are fixed to the inner sides of two adjacent groups of arc-shaped steel plates, and double rows of reinforcing bolts are fixedly connected between the two adjacent groups of channel steels, and sealing rings that are clamped tightly to the outer sides of the circular plugs are provided on the inner sides of the three groups of arc-shaped steel plates; Two groups of C-shaped guide rails with openings facing each other are arranged on the front and rear sides of the working pit, a lower plate groove is arranged on the top of the guide rail near the driving assembly, and an upper plate groove is arranged on the top of the guide rail near the steel blade foot assembly, a containing frame is fixed inside the working pit above the lower plate groove, the containing frame is a through structure vertically connected to the lower plate groove, and multiple groups of top iron plates are vertically stacked inside the containing frame; The driving assembly includes a plurality of groups of oil cylinders arranged longitudinally and fixed on the cast-in-place reaction wall, the telescopic ends of the plurality of groups of oil cylinders are longitudinally connected with pressure plates for pushing the bell-and-spigot pipes to move, and the top side of the pressure plate extends away from the bell-and-spigot pipes to form a limit plate supporting the top iron plate; The thickness of the top iron plate is greater than the vertical height of the pressure plate, and the front and rear sides of the interior of the accommodating frame are both provided with sliding grooves for supporting the vertical sliding of the top iron plate, and the spacing between the two groups of the sliding grooves is equal to the longitudinal width of the opening of the lower plate groove; Step (2): dig a starting shaft in the working pit, adopt an open-cut method, excavate in sections, support in sections, use reinforced concrete to construct the reinforced concrete bottom plate on the surrounding retaining walls, and then construct a cast-in-place reaction wall. Install two sets of parallel guide rails in the working pit according to the actual three-dimensional spatial position, and install a containing frame in the working pit above the upper plate groove of the guide rail, and stack multiple sets of top iron plates in the containing frame; Two groups of support brackets for supporting the bell-and-spigot pipes are symmetrically arranged on the front and rear sides of the working pit below the guide rail, and the support brackets include a crossbeam transversely fixed on the inner wall of the working pit, and the crossbeam is a C-shaped frame with an opening facing upward, and a plurality of groups of rotating seats are evenly distributed on the top of the crossbeam along its length direction, and guide rollers are rotatably matched on the rotating seats, and the outer sides of the guide rollers are tightly pressed against the outer circumference of the bell-and-spigot pipes; Step (3): Install a cylinder as a propulsion jack on the cast-in-place reaction wall, and use the limit plate on the pressure plate at the telescopic end of the cylinder as a support structure to prevent the top iron plate from falling. Then, hoist the prefabricated bell-and-spigot pipe into the working pit, and use the telescopic end of the cylinder to extend and then push the bell-and-spigot pipe through the pressure plate to extend it into the soil layer under the guiding cutting action of the steel blade foot assembly at its end; Step (4): After the oil cylinder is extended to the maximum stroke, the telescopic end of the oil cylinder contracts, and the oil cylinder drives the pressure plate and the limit plate to move away from the socket pipe until the limit plate moves to a state of separation from the top iron plate in the accommodating frame. At this time, the support effect on the top iron plate is released, and multiple groups of vertically stacked top iron plates fall downward at the same time. The bottom group of top iron plates falls into the two groups of guide rails along the lower plate groove. This group of top iron plates is located between the telescopic end of the oil cylinder and the socket pipe. At this time, the oil cylinder in the contracted state is extended again to use the fallen group of top iron plates as an extended force-bearing component, thereby completing the second pipe jacking action; Step (5): When the second jacking action of the bell-and-spigot pipe is completed, the oil cylinder reaches the maximum extension stroke again. At this time, the oil cylinder contracts to drive the pressure plate and the limit plate to retreat, and the lowest set of jacking iron plates in the accommodating frame continues to fall into the guide rail along the lower plate groove. The jacking iron plates are automatically dropped during the extension and retraction of the oil cylinder, thereby continuously adding to the length of the jacking irons, so that multiple sets of jacking irons fall down in sequence and are connected end to end to transmit the jacking power until the bell-and-spigot pipe is completely pushed into the soil layer. The staff takes out the multiple sets of jacking iron plates in sequence along the upper plate groove to complete the jacking process of a section of the bell-and-spigot pipe.

2. According to claim 1, a pipe jacking construction method with external ring cutting and jacking is characterized in that: In step (1), the double-row reinforcement bolts are M12 bolts, the number of the double-row reinforcement bolts is eight groups and they are evenly distributed in two columns laterally, and a 45° blade foot groove is provided at the front end of the outer side of the arc-shaped steel plate.

3. The pipe jacking construction method of external ring cutting jacking according to claim 1 is characterized in that: In step (1), an L-shaped reaction force dispersion frame is provided on the side of the cast-in-place reaction force wall away from the bell-and-spigot pipe, which is pressed against the bottom side of the working pit, and a right-angled triangular reinforcement rib is provided on the inner side of the reaction force dispersion frame; Two groups of mounting frames are fixed on the front and rear sides of the top of the accommodating frame. The top of the mounting frame extends toward the inner side wall of the working pit, and mounting grooves for supporting the mounting frame are arranged on the front and rear sides of the top of the working pit.

4. The pipe jacking construction method of external ring cutting jacking according to claim 1 is characterized in that: The two ends of the guide rail are respectively fixed to the inner wall of the working pit and the cast-in-place reaction wall by expansion bolts, and the opening widths of the upper plate groove and the lower plate groove are both greater than the width of the top iron plate.

5. The pipe jacking construction method of external ring cutting jacking according to claim 1 is characterized in that: In step (2), the pressure plate and the limit plate are both made of Q345B steel and are fixed by welding, and the limit plate and the pressure plate are fixed to the output end of the cylinder by bolts.

6. The pipe jacking construction method of external ring cutting jacking according to claim 5 is characterized by: The arc-shaped steel plate is Q345B steel with a thickness of 5 mm. The outer side of the arc-shaped steel plate is flush with the outer circumference of the socket pipe. The yield strength of the channel steel is ≥345N / mm², the tensile strength is 470-630Mpa, and the impact energy is ≥34kJ / m².

7. The pipe jacking construction method of external ring cutting jacking according to claim 1, characterized in that: In step (3), the bell-and-spigot pipe is a prefabricated reinforced concrete pipe structure, and the wall thickness of the bell-and-spigot pipe is 120 mm, and the outer circumferential side of the arc-shaped steel plate of the steel blade foot assembly is flush with the outer side wall of the bell-and-spigot pipe.

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