Detachable hole door sealing steel ring for large-section rectangular pipe jacking construction

Abstract

The detachable hole portal sealing steel ring for the close construction of the super-large-section rectangular jacking pipe belongs to the technical field of underground passage construction engineering and comprises a hole portal steel ring assembled and a temporary steel lattice beam arranged at the middle position of the hole portal steel ring. The temporary steel lattice beam can be turned over to adapt to the jacking excavation on both sides. The end of the hole portal steel ring is turned outward to form an L-shaped structure. Anchor bars are welded to the outer side of the hole portal steel ring. The detachable hole portal sealing steel ring can make the left and right jacking constructions smoothly proceed, effectively ensure the safety of the jacking machine during multiple launching and receiving, avoid the water and sand gushing phenomenon of the jacking machine during the shallow-buried excavation of the large-section construction, facilitate the timely and effective control of the dangerous situation, and has simple structure and high practicability.

Description

Technical Field

[0001] This invention relates to the field of underground tunnel construction technology, and in particular to a detachable portal sealing steel ring for the close-fitting construction of ultra-large cross-section rectangular pipe jacking. Background Technology

[0002] With the rapid development of urban subways in my country, pipe jacking engineering has entered a period of rapid development. Currently, the width of rectangular pipe jacking in China is generally 6m and the height is 3m. Research on portal steel rings for the close-fitting construction of ultra-large cross-section rectangular pipe jacking (22.9m × 13.83m) is still lacking, making this a first. Setting up portal steel rings is beneficial for waterproofing the nodes between stations and tunnels. Since the pipe jacking machine must pass through the portal steel ring during initiation and reception, its fabrication and installation accuracy are crucial, as it will affect the position of the pipe jacking machine when entering and exiting the tunnel. In shallow buried soil strata, the construction of ultra-large cross-section rectangular pipe jacking is a high-risk operation, highly susceptible to water and sand flow problems in the gap between the portal steel ring and the pipe jacking machine, which can lead to sudden accidents such as surface subsidence and property damage. Therefore, research on portal steel ring technology for the close-fitting construction of ultra-large cross-section rectangular pipe jacking in shallow buried tunnels is essential.

[0003] For small and medium-sized pipe jacking projects, the portal steel ring is usually an integral type. However, for ultra-large cross-section rectangular pipe jacking projects, the integral portal steel ring is heavy and large in size. The overall hoisting requires high-performance hoisting machinery, poses a high safety risk, and the hoisting deformation cannot be controlled. The positioning and adjustment of the portal steel ring during installation is also difficult.

[0004] Meanwhile, due to the extremely large cross-section of the tunnel, a two-stage close-fitting pipe jacking construction method was adopted. This method involves dividing the cross-section into left and right halves, completing the left-side pipe jacking construction first, followed by the right-side pipe jacking construction, and then removing the intermediate temporary pipe segments through structural system conversion to form a whole. Therefore, a detachable portal steel ring structure suitable for close-fitting construction of rectangular pipe jacking in ultra-large cross-sections is required. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a detachable tunnel portal sealing steel ring for the close-fitting construction of ultra-large cross-section rectangular jacking pipes.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The detachable portal sealing steel ring used for the close-fitting construction of ultra-large cross-section rectangular pipe jacking includes the portal steel ring assembled together, and a temporary steel grid beam set in the middle of the portal steel ring.

[0008] The temporary steel grating beams can be flipped to adapt to the jacking excavation on both sides respectively;

[0009] The end of the portal steel ring is turned outward in an "L" shape;

[0010] Anchor bars are welded to the outer side of the portal steel ring.

[0011] In some embodiments, the anchor bars include straight anchor bars welded to the long side of the "L"-shaped structure and oblique anchor bars welded to the short side of the "L"-shaped structure.

[0012] In some embodiments, the inclined anchor bar is in a bent shape, with one end fixedly welded to the portal steel ring and the other end bent inward.

[0013] In some embodiments, the bent section of the inclined anchor bar forms an angle of 20 to 40 degrees with the short side of the portal steel ring.

[0014] In some embodiments, a water-swellable sealing strip is provided on the outer side of the portal steel ring.

[0015] In some embodiments, the portal steel ring and temporary steel grating beam are provided with screw holes for installing rubber waterstop curtains.

[0016] In some embodiments, the temporary steel grating beam is formed by welding two I-beams side by side.

[0017] In some embodiments, curved corner plates are provided at the top and bottom positions on one side of the temporary steel grating beam;

[0018] The temporary steel grating beam is equipped with connecting plates at its upper and lower ends.

[0019] In some embodiments, reinforcing supports are provided at the four corners of the portal steel ring.

[0020] In some embodiments, the assembly steps of the portal steel ring are as follows:

[0021] On the end wall, mark and position the control points of the pre-embedded steel ring outline;

[0022] The lower part of the portal steel ring is assembled on the ground and then hoisted down into the well for installation;

[0023] Then, the lower part of the temporary steel grating beam is hoisted down into the well for installation; at the same time, inner ring supports are added.

[0024] Then, the upper part of the portal steel ring is assembled on the ground and hoisted down into the well for installation;

[0025] Finally, the upper part of the temporary steel grating beam was hoisted down into the well for installation, and an inner ring support was added.

[0026] Compared with the prior art, the present invention provides a detachable portal sealing steel ring for the close-fitting construction of ultra-large cross-section rectangular jacking pipes, which has the following beneficial effects.

[0027] 1. In this invention, the left and right jacking operations are carried out smoothly, effectively ensuring the safety of multiple starts and stops of the pipe jacking machine, avoiding water and sand inrush during shallow buried tunneling with large cross-section construction, and facilitating timely and effective control of any emergencies; at the same time, the device has a simple structure and strong practicality.

[0028] 2. In this invention, the temporary steel grating beam is detachable and movable, serving two closely spaced openings on the left and right, saving materials and reducing costs; the portal steel ring is manufactured and assembled in sections, facilitating transportation; at the same time, the hoisting safety risk is small, and the deformation is minimal; the segmented construction of the portal steel ring makes it easier to control the installation accuracy of each ring, more accurate in positioning and adjustment, and easier to meet design and installation requirements; moreover, it can reduce construction difficulty and ensure construction quality.

[0029] 3. In this invention, the portal steel ring is outwardly folded into an "L" shape, which has higher strength and resistance to deformation; anchor bars are welded to the outer side of the portal steel ring to enhance the overall connection strength and positioning accuracy; after concrete pouring, the connection strength with the portal is reliable, the position is accurate, and there is no deviation; a ring of main reinforcement is set on the inner ring side of the portal steel ring for auxiliary positioning; after installation, the main reinforcement is welded to the portal steel ring to further improve the installation strength, reliability, and positioning accuracy; the inclined anchor bars are bent in shape, with an angle of ~ degrees, to further ensure reliability;

[0030] 4. In this invention, the temporary steel grating beam is formed by welding two I-beams side by side, possessing good load-bearing capacity and reliable strength; a connecting plate is provided to connect with the portal steel ring, making it easier to rotate; supports are provided inside the ring to ensure that the steel ring will not deform due to concrete compression during the construction of the end wall concrete, thus affecting the accuracy and dimensions of the steel ring; reinforcing braces are provided at the four corners to further ensure strength and structural stability.

[0031] Other advantages, objectives and features of the invention will be set forth in part in the description which follows; and in part will be apparent to those skilled in the art upon examination of the following description; or may be learned from practice of the invention. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the present invention.

[0033] Figure 2 for Figure 1 A magnified structural diagram of point A in the middle.

[0034] Figure 3 for Figure 1 A magnified structural diagram at point B in the middle.

[0035] Figure 4 This is a front view structural diagram of the present invention.

[0036] Figure 5 This is a schematic diagram of the rear structure of the present invention.

[0037] Figure 6 for Figure 5 A magnified structural diagram at point C.

[0038] Figure 7 This is a structural schematic diagram of a temporary steel grating beam.

[0039] Figure 8 This is a partial structural schematic diagram of a temporary steel grating beam.

[0040] Figure 9 This is a cross-sectional view of a temporary steel grating beam.

[0041] Figure 10 This is a partial cross-sectional view of the steel ring at the tunnel entrance.

[0042] Figure 11 This is an exploded view of the present invention.

[0043] Figure 12 for Figure 9 Right view of blocks ① and ② in the middle.

[0044] Figure 13 This is a schematic diagram of the working state of the present invention.

[0045] Figure 14 This is a schematic diagram showing the configuration with internal steel supports.

[0046] Figure 15 This is a construction status diagram of the present invention.

[0047] In the picture:

[0048] 1. Portal steel ring; 2. Temporary steel grating beam; 3. Straight anchor bar; 4. Inclined anchor bar; 5. Water-swellable waterstop strip; 6. Screw hole; 7. Corner plate; 8. Connecting plate. Detailed Implementation

[0049] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0050] Reference Figure 1-15 A detachable portal sealing steel ring for the tight-fitting construction of ultra-large cross-section rectangular pipe jacking includes a portal steel ring 1 assembled from parts, and a temporary steel grid beam 2 set in the middle of the portal steel ring 1.

[0051] Among them, the portal steel ring 1, after assembly, has an overall structure of a rectangular ring; preferably, it is made of Q235B steel plate with a thickness of 16mm.

[0052] The temporary steel grating beam 2 is vertically fixed in the middle of the portal steel ring 1; this temporarily divides one portal into two portals, which is suitable for supporting the jacking excavation, allowing the pipe jacking machine to perform close-fitting jacking excavation in two separate operations, left and right.

[0053] Furthermore, the temporary steel grating beam 2 can be flipped to adapt to the jacking excavation on both sides respectively; for example, after the jacking construction on the left side is completed, the temporary steel grating beam 2 in the middle is flipped 180° along the vertical centerline to serve as the left steel beam of the right-line tunnel portal steel ring, stabilizing the soil around the tunnel entrance.

[0054] When using this device, install the aforementioned portal steel ring 1 according to the jacking construction plan, and set the position of the temporary steel grating beam 2 accordingly to adapt to the construction; after the construction on one side is completed, adjust the position of the temporary steel grating beam 2 to adapt to the construction on the other side.

[0055] It should be noted that the temporary steel grating beam 2 can be fixed by welding, and when replacement is needed, the welding points can be cut open, the position moved, and then welded again; alternatively, a detachable bolt connection can be used, etc.

[0056] In some embodiments, the end of the portal steel ring 1 near the portal is turned outward into an "L" shape; it has higher strength and resistance to deformation.

[0057] Correspondingly, the long side of the "L"-shaped structure is adapted to the tunneling construction and is used to install the entrance to the tunnel; the short side of the "L"-shaped structure serves as the outer edge, close to the inner side of the working shaft, forming a retaining ring structure.

[0058] Preferably, for the close-fitting construction of ultra-large cross-section rectangular jacking pipe (22.9m×13.83m), the long side of the "L" shape is set to 1000mm and the short side to 300mm.

[0059] Furthermore, anchor bars are welded to the outside of the portal steel ring 1 to enhance the overall connection strength and positioning accuracy; after the concrete is poured, the connection strength with the portal is reliable, the position is accurate, and there is no deviation.

[0060] It is understandable that grouting holes are provided on the portal steel ring 1.

[0061] like Figure 11 As shown, there are multiple grouting holes to accommodate each assembled panel and ensure reliable and convenient grouting at each location.

[0062] Understandably, the grouting holes are located on the long side of the portal steel ring 1.

[0063] Preferably, a ring of pre-reserved grouting pipe passage holes is provided on the long side of the portal steel ring 1, and they are arranged at equal intervals along the circumferential direction of the steel ring.

[0064] In some embodiments, the anchor bars include straight anchor bars 3 welded to the long side of the "L"-shaped structure and oblique anchor bars 4 welded to the short side of the "L"-shaped structure.

[0065] Understandably, main reinforcement bars are also installed in the end wall at the portal, and the anchor bars on the portal steel ring 1 cooperate with them.

[0066] In some embodiments, a main reinforcing bar embedded in the end wall is provided on the inner ring side of the portal steel ring 1; auxiliary positioning is performed when installing the portal steel ring 1; at the same time, after installation, the main reinforcing bar is welded to the portal steel ring 1 to further improve the strength, reliability and positioning accuracy of the installation.

[0067] In some embodiments, the straight anchor bar 3 is provided with two rings.

[0068] Preferably, two rings of ⌀16 pre-embedded anchor bars (straight anchor bars 3) are evenly welded at 150mm intervals on the outer side of the long side of the portal steel ring, with a length of 500mm; a ring of ⌀12 inclined anchor bars are evenly welded at 150mm intervals on the outer side of the short side of the portal steel ring, with a length of 380mm; the pre-embedded anchor bars are welded to the main reinforcement bars in the end wall.

[0069] In some embodiments, the inclined anchor bar 4 is in a bent shape, with one end fixedly welded to the portal steel ring 1 and the other end bent inward.

[0070] like Figure 10 As shown, the bent section of the inclined anchor bar 4 forms an angle of 20 to 40 degrees with the short side of the portal steel ring 1.

[0071] Preferably, the included angle is set to 30 degrees.

[0072] In some embodiments, a water-swellable sealing strip 5 is provided on the outer side of the portal steel ring 1.

[0073] In some embodiments, the portal steel ring 1 and the temporary steel grating beam 2 are provided with screw holes 6 for installing rubber waterstop curtains.

[0074] It is understandable that the screw hole 6 is set on the short side of the steel ring 1 of the tunnel entrance; preferably, several screw holes 6 are reserved evenly at intervals of 250mm.

[0075] In some embodiments, the temporary steel grating beam 2 is formed by welding two I-beams side by side.

[0076] like Figure 9 The figure shown is a top sectional view of temporary steel grating beam 2; it has good load-bearing capacity and reliable strength.

[0077] Preferably, two HM500X300 I-beams are used.

[0078] Furthermore, it is understandable that the screw hole 6 for installing the rubber waterstop curtain should be matched to the flipped state and opened on the flange of the I-beam.

[0079] In addition, it is understandable that temporary steel grating beams 2 are arranged on the steel rings of the starting end portal and the receiving end portal, for a total of two sets.

[0080] In some embodiments, curved corner plates 7 are provided on one side of the temporary steel grating beam 2 at the upper and lower positions to adapt to the overall structure.

[0081] It should be noted that the curved corner plate 7 is to correspond to the corner structure of the portal steel ring 1, and is not necessary; similarly, the corner structure of the portal steel ring 1 is to improve strength, and is not a necessary feature.

[0082] In some embodiments, the upper and lower ends of the temporary steel grating beam 2 are provided with connecting plates 8, and bolts are passed through the connecting plates 8 to connect with the portal steel ring 1.

[0083] like Figure 3 , 7 As shown in Figures 8 and 8, the connecting plate 8 is a flat plate that is connected to the temporary steel grating beam 2 and the arc-shaped plate 7 to form the upper and lower installation structures. When fixing the temporary steel grating beam 2, bolts are inserted through the reserved bolt holes to connect it to the portal steel ring 1.

[0084] Using bolted connections makes it easier to flip the temporary steel grating beam 2; however, it is important to note that the bolted connections must be strong enough.

[0085] Similarly, it can also be welded directly.

[0086] In some embodiments, the portal steel ring 1 is composed of eight pieces; the pieces are connected by bolts and welded together.

[0087] Understandably, the portal steel ring is manufactured in eight pieces, transported to the site, assembled, and then installed. The assembly uses bolt connections and continuous welding to ensure strength and reliability.

[0088] like Figure 11 As shown; ①~⑩ are the component blocks of the portal steel ring 1 and the temporary steel grating beam 2; the portal steel ring 1 includes four corner positions and four straight sections, and the temporary steel grating beam 2 is composed of upper and lower parts.

[0089] The steel ring is large in size, making it difficult to hoist it as a whole. The solution is to process it into sections, hoist them into the well, and then install them. This will reduce the difficulty of construction and ensure the quality of construction.

[0090] It should be noted that because the steel ring embedded in the portal is a long and narrow component, it is prone to bending and twisting during assembly; in order to ensure the quality of assembly, the outline of the steel ring must be strictly controlled.

[0091] The assembly steps for the portal steel ring 1 are as follows:

[0092] On the end wall, mark and position the control points of the pre-embedded steel ring outline;

[0093] First, assemble the four lower parts ①, ②, ③, and ④ of the portal steel ring 1 on the ground, totaling 6.62t, and then hoist them down into the well for installation;

[0094] Then, the lower part of the temporary steel grating beam 2, component 9, is hoisted down into the well for installation; at the same time, an inner ring support is added.

[0095] like Figure 14 As shown, the steel ring 1 of the tunnel portal is provided with internal supports in both horizontal and vertical directions; preferably, two rows of steel supports are provided in front and behind to temporarily support the steel ring 1 of the tunnel portal; at this time, the temporary steel grating beam 2 is not set up.

[0096] Then, the upper four parts ⑤, ⑥, ⑦, and ⑧ of the portal steel ring 1 were assembled on the ground, totaling 5.68t, and then hoisted down into the well for installation;

[0097] Finally, the upper part of the temporary steel grating beam 2, component 10, was hoisted down into the well for installation, and an inner ring support was added.

[0098] The components are connected by bolts and are embedded into the steel mesh of the inner lining wall with the required precision.

[0099] It is understandable that the temporary steel grating beam 2 can be installed after the concrete is poured; in the above steps, only components ①~⑧ and the inner ring support are installed.

[0100] After installation, measure and check the position and clearance radius of the steel ring, and whether it meets the accuracy requirements for being horizontal and vertical to the tunnel centerline. If it does not meet the requirements, adjustments must be made. During the adjustment process, use a hand-operated hoist to lift and place the steel ring. If the hand-operated hoist does not have a fulcrum, a fulcrum can be welded to the wall, using a tripod made of channel steel to form a fulcrum.

[0101] Regarding the installation of the inner ring supports: To ensure that the steel ring will not deform due to concrete compression during the end wall concrete construction process, thus affecting the accuracy and dimensions of the steel ring, steel supports are installed inside the steel ring and welded to it for reinforcement. The supports are made of [12 channel steel, with a total of 4 rows of horizontal supports and 6 rows of vertical supports, with two supports in each row, one at the front and one at the back.

[0102] Specific layout as follows Figure 14 As shown (temporary steel grating 2 is shown, or may not be installed).

[0103] In some embodiments, reinforcing supports are provided at the four corners of the portal steel ring 1.

[0104] like Figure 11As shown; the reinforcing brace includes diagonal braces connected at both ends to the inner side of the portal steel ring 1, and short braces connecting the portal steel ring 1 and the diagonal braces.

[0105] like Figure 12 As shown, the reinforcing brace is made of 20# channel steel; preferably, it is set in two rows, front and back.

[0106] This invention provides a detachable portal sealing steel ring structure for tight-fitting construction of ultra-large cross-section rectangular pipe jacking. It prepares for two separate tight-fitting jacking operations (left and right), controls the risk of sand and water inrush at the portal, and ensures the safety of the pipe jacking machine's starting and receiving phases. The portal steel ring structure of this invention allows for smooth two-stage jacking operations, effectively ensuring the safety of multiple starting and receiving phases of the pipe jacking machine, avoiding sand and water inrush during shallow-buried, large-section tunneling, and facilitating timely and effective control of any potential hazards. Furthermore, the device has a simple structure and is highly practical.

[0107] This invention addresses the problem of large-sized and easily deformable portal steel rings by using temporary steel grating beams to support the portal. These temporary steel grating beams are detachable and movable, serving both adjacent portal openings, thus saving materials and reducing costs. The portal steel rings are manufactured and assembled in sections, facilitating transportation. Furthermore, the hoisting safety risks are low, resulting in minimal deformation. The segmented construction of the portal steel rings allows for easier control of the installation accuracy of each section, more precise positioning and adjustment, and better fulfillment of design and installation requirements. Additionally, it reduces construction difficulty and ensures construction quality.

[0108] In this invention, the portal steel ring 1 is outwardly folded into an "L" shape, which has higher strength and resistance to deformation. Anchor bars are welded to the outer side of the portal steel ring 1 to enhance the overall connection strength and positioning accuracy. After concrete is poured, the connection strength with the portal is reliable, the position is accurate, and there is no deviation. A ring of main reinforcement is set on the inner ring side of the portal steel ring 1 for auxiliary positioning. After installation, the main reinforcement is welded to the portal steel ring 1 to further improve the installation strength, reliability, and positioning accuracy. The inclined anchor bar 4 is bent at an angle of 20 to 40 degrees to further ensure reliability.

[0109] In this invention, the temporary steel grating beam 2 is made of two I-beams welded side by side, which has good load-bearing performance and reliable strength; a connecting plate 8 is set to connect with the portal steel ring 1, which makes it easier to flip over; a support is set inside the ring to ensure that the steel ring will not be deformed by the concrete pressure during the construction of the end wall concrete, thus affecting the accuracy and size of the steel ring; and a reinforcing brace is set at the four corners to further ensure strength and structural stability.

[0110] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0111] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0112] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A detachable portal sealing steel ring for tight-fitting construction of ultra-large cross-section rectangular pipe jacking, characterized in that, It includes a portal steel ring (1) assembled from parts, and a temporary steel grating beam (2) set in the middle of the portal steel ring (1); After assembly, the portal steel ring (1) has a rectangular ring as a whole structure; the temporary steel grating beam (2) is vertically fixed in the middle position of the portal steel ring (1), temporarily dividing one portal into two portals, which is suitable for supporting the jacking excavation; The temporary steel grating beam (2) is made of two I-beams welded side by side; it can be flipped to adapt to the jacking excavation on both sides respectively; The end of the portal steel ring (1) is turned outward into an "L" shape; the long side of the "L" shape is adapted to the tunneling construction and is buried at the portal position; the short side of the "L" shape serves as the outer edge, close to the inner side of the working shaft, forming a retaining ring structure. An anchor bar is welded to the outside of the portal steel ring (1); after the concrete is poured, it is connected to the portal. The anchor bars include straight anchor bars (3) welded to the long side of the "L" shaped structure and oblique anchor bars (4) welded to the short side of the "L" shaped structure; main reinforcement bars are also provided at the end wall of the portal, and the anchor bars on the portal steel ring (1) cooperate with them. The straight anchor bar (3) is provided with two rings; the inclined anchor bar (4) is in a bent shape, with one end fixedly welded to the portal steel ring (1) and the other end bent inward; The outer side of the portal steel ring (1) is provided with a water-swellable water-stop strip (5). The portal steel ring (1) and temporary steel grating beam (2) are provided with screw holes (6) for installing rubber waterstop cloth. The temporary steel grating beam (2) has an arc-shaped plate (7) installed on one side at the top and bottom. The temporary steel grating beam (2) is provided with connecting plates (8) at its upper and lower ends; The assembly steps of the portal steel ring (1) are as follows: On the end wall, mark and position the control points of the pre-embedded steel ring outline; Assemble the lower part of the portal steel ring (1) on the ground and hoist it down into the well for installation; Then, the lower part of the temporary steel grating beam (2) is hoisted down into the well for installation; at the same time, an inner ring support is added; Then, the upper part of the portal steel ring (1) is assembled on the ground and hoisted down into the well for installation; Finally, the upper part of the temporary steel grating beam (2) was hoisted down into the well for installation, and an inner ring support was added; After installation, measure and check the position and clearance radius of the steel ring, and whether it meets the accuracy requirements of being horizontal and vertical to the center line of the tunnel. If it does not meet the requirements, adjustments must be made. During the adjustment process, use a hand-operated hoist to lift and place the steel ring. If the hand-operated hoist has no support point, a support point can be welded to the ground wall, and a tripod made of channel steel can be used to form a support point.

2. The detachable portal sealing steel ring for tight-fitting construction of ultra-large cross-section rectangular pipe jacking as described in claim 1, characterized in that, The portal steel ring (1) is composed of eight pieces; each piece is connected by bolts and welded together.

3. The detachable portal sealing steel ring for ultra-large cross-section rectangular pipe jacking construction according to claim 1, characterized in that, The bent section of the inclined anchor bar (4) forms an angle of 20 to 40 degrees with the short side of the portal steel ring (1).

4. The detachable portal sealing steel ring for ultra-large cross-section rectangular pipe jacking construction according to claim 1, characterized in that, Two rings of φ16 pre-embedded anchor bars are evenly welded at 150mm intervals on the outer side of the long side of the portal steel ring, with a length of 500mm. A ring of φ12 inclined anchor bars is evenly welded at 150mm intervals on the outer side of the short side of the portal steel ring, with a length of 380mm. The pre-embedded anchor bars are then welded to the main reinforcement bars inside the end wall.

5. The detachable portal sealing steel ring for tight-fitting construction of ultra-large cross-section rectangular pipe jacking as described in claim 1, characterized in that, The portal steel ring (1) is provided with grouting holes; There are multiple grouting holes, which are set on the long side of the portal steel ring (1).

6. The detachable portal sealing steel ring for ultra-large cross-section rectangular pipe jacking construction according to claim 1, characterized in that, The four corners of the portal steel ring (1) are provided with reinforcing supports.

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