Construction method for conversion of vertical support system at the interface between cross passage and expanded tunnel

Abstract

The present invention relates to the technical field of subway station construction, and in particular to a method for converting the vertical support system at the interface of a transverse passage and an expanded tunnel, comprising the following steps: S1, constructing a vertical shaft and preparing a supporting structure around the vertical shaft; S2, constructing an upper tunnel for the transverse passage; S3, constructing a middle tunnel for the transverse passage; S4, reinforcing, backfilling, and demolishing shield segments; S5, installing a gantry at the tunnel; S6, expanding the tunnel end and using the gantry to construct a force-bearing system conversion for the transverse passage wall; S7, constructing a lower pilot tunnel for the transverse passage; and S8, expanding the tunnel. First, constructing the vertical shaft and the support around the shaft facilitates the entry of construction equipment, and then constructing the upper tunnel, middle tunnel, and lower tunnel in sequence can minimize safety risks. Furthermore, the gantry at the tunnel is used to convert the force-bearing system of the transverse passage wall, thereby facilitating tunnel expansion, further reducing safety hazards, and ensuring construction safety.

Description

Technical Field

[0001] The present invention relates to the technical field of subway station construction, and in particular to a construction method for converting a vertical support system at an interface between a transverse passage and an expanded tunnel. Background Art

[0002] During subway construction, a tunnel is usually excavated using a shield machine and supported by shield segments. However, the tunnel excavated by the shield machine is small and can only accommodate subway trains. In subway station areas, platforms are required to facilitate pedestrian boarding, so it is generally necessary to excavate a cross passage and expand the tunnel on the platform side to facilitate the installation of related facilities. However, the construction space at the joint between the cross passage and the platform tunnel is extremely small, and all operations are underground, which poses a high safety risk. Therefore, a safe construction plan for the interface between the cross passage and the tunnel is urgently needed. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: in order to solve the technical problems in the prior art, the present invention provides a construction method for converting the vertical support system of the interface between the transverse channel and the expanded tunnel.

[0004] The technical solution adopted by the present invention to solve its technical problems is: a construction method for converting the vertical support system at the interface of a transverse channel and an expanded tunnel, comprising the following steps: S1, constructing a vertical shaft and preparing a supporting structure around the vertical shaft; S2, constructing an upper tunnel of the transverse channel; S3, constructing a middle tunnel of the transverse channel; S4, reinforcing, backfilling and demolishing shield segments; S5, installing a gantry at the tunnel; S6, expanding the tunnel end, and relying on the gantry to build a force system conversion for the transverse channel wall; S7, constructing a lower pilot tunnel of the transverse channel; and S8, expanding the tunnel.

[0005] The construction method for converting the vertical support system at the interface between the transverse passage and the expanded tunnel of the present invention first constructs the vertical shaft and the support around the vertical shaft to facilitate the entry of construction equipment, and then constructs the upper tunnel, the middle tunnel, and the lower tunnel in sequence, which can minimize safety risks. In addition, the portal frame at the tunnel is used to realize the conversion of the force system of the transverse passage wall, thereby facilitating the expansion of the tunnel, further reducing safety hazards, and ensuring construction safety.

[0006] Furthermore, when constructing the tunnel on the transverse channel, the construction shaft is first extended to the bottom of the tunnel on the transverse channel for the first temporary bottom sealing, and then the arch of the transverse channel is advanced to support the tunnel, and the shaft is excavated to a position about 0.3m below the bottom plate of the tunnel on the transverse channel for the second temporary bottom sealing. After that, the shaft retaining structure of the tunnel on the transverse channel is removed, and the initial support at the opening position is constructed, with three steel frames densely arranged in sequence; then the tunnel on the transverse channel is excavated, and support construction is carried out simultaneously during excavation, that is, partition walls and partitions are constructed. Finally, the tunnel on the transverse channel is excavated to the position of the end wall of the transverse channel, and the end sealing is completed.

[0007] Furthermore, the construction of the middle tunnel of the transverse channel is carried out in two steps. First, the vertical shaft is excavated to a position about 0.3m below the bottom plate of the middle tunnel-1 of the transverse channel, and the third temporary bottom sealing is carried out; the retaining structure of the vertical shaft of the middle tunnel-1 of the transverse channel is chiseled out, and the initial support of the opening position is constructed, with three steel frames densely arranged in sequence. Then the middle guide tunnel-1 of the transverse channel is excavated, and the support construction is carried out simultaneously, that is, the partition walls and partitions are constructed, and the middle tunnel-1 of the transverse channel is excavated to the position of the end wall of the transverse channel, and the end sealing is completed; then the construction of the middle tunnel-2 of the transverse channel is completed according to the above steps.

[0008] Furthermore, during the reinforcement, backfilling and demolition of the shield segments, the interval segments are first longitudinally tightened, circumferentially supported and partially backfilled within the cross channel range. Subsequently, M7.5 mortar is backfilled within the range 0.5m outside the cross channel excavation contour line and within 1m of the interval end excavation contour line, backfilled to half the height of the segments. A breaker hammer is then used to demolish the shield segments, and the removal of the segments at the intersection of the tunnel and the cross channel is carried out simultaneously with the excavation of the cross channel middle tunnel-2. During construction, I-beams are used as temporary support steel frames to achieve temporary conversion of the force system. That is, support rods are continuously installed during the excavation process. After the support rods are installed, reinforcing steel bars are welded on multiple support rods.

[0009] Furthermore, during the construction of the cross-channel middle tunnel-2, part of the middle partition wall of the cross-channel middle tunnel-1 located above the tunnel was demolished, and then a temporary fixing plate was constructed in the cross-channel middle tunnel-1. The temporary fixing plate was extended with the side wall of the cross-channel middle tunnel-1 using I-shaped steel and longitudinal connecting reinforcement, and was connected to the temporary fixing plate through the cross-channel side wall locking anchor pipe within the platform tunnel to improve the safety of force conversion; then the gantry was installed along the temporary fixing plate, and the top of the gantry was installed first and concrete was poured, and then excavation was carried out from top to bottom, and the support legs of the gantry were installed in sections during the excavation process, and the temporary conversion of the force system was realized again; at the same time, a pipe shed was driven into the gantry to form an advance support for the tunnel expansion, and the steel frame of the tunnel entrance was densely arranged, and then the cross-channel side wall steel frame and the densely arranged steel frame were welded and sprayed to form a whole, and the force system conversion was realized again.

[0010] Furthermore, when the tunnel under the transverse channel is excavated, the vertical shaft is pulled to a position about 0.3m below the bottom plate of the tunnel under the transverse channel, and the fourth bottom sealing is carried out; when the tunnel under the transverse channel is excavated, the shield segments are removed, and the gantry support legs are extended at the same time, and the loose sections of the support legs and the foundation are backfilled with concrete.

[0011] Furthermore, the temporary support steel frame includes a support rod, and multiple support rods are provided in the horizontal direction; a reinforcement member connected to adjacent support rods to relatively fix the adjacent support rods, and the reinforcement member includes a first clamping jaw, suitable for connecting to a support rod; a telescopic rod, suitable for connecting to the first clamping jaw; a second clamping jaw, connected to an end of the telescopic rod away from the first clamping jaw, and suitable for connecting to another adjacent support rod; and reinforcing steel bars, connected to all support rods.

[0012] Furthermore, the telescopic rod includes a first rod and a second rod, the first rod is inserted into the second rod, and the second rod is provided with a locking piece, which is suitable for locking the first rod and the second rod; the first rod is connected to the first clamping claw, and the second rod is connected to the second clamping claw.

[0013] Furthermore, the locking member includes a locking plate and a locking sleeve. The locking plate is connected to the end face of the second rod and is provided in plurality along the circumference of the second rod. The plurality of locking plates are arranged around the first rod. The locking sleeve is sleeved on the plurality of locking plates and is threadedly connected to the locking plates. The diameters of the plurality of locking plates gradually increase in the direction from the second clamping jaw toward the first clamping jaw.

[0014] Furthermore, a universal joint is connected between the first clamping jaw and the first rod, and between the second clamping jaw and the second rod respectively.

[0015] The beneficial effects of the present invention are:

[0016] 1. First, construct the vertical shaft and the support around it to facilitate the entry of construction equipment. Construction is then carried out in the order of the upper tunnel, middle tunnel, and lower tunnel to minimize safety risks. In addition, the portal frame at the tunnel is used to achieve the transformation of the load-bearing system of the cross-channel wall, thereby facilitating the expansion of the tunnel, further reducing safety hazards and ensuring construction safety.

[0017] 2. After the middle partition wall of the cross passageway tunnel-1 was removed, a portal frame was used for reinforcement, raising the height of the tunnel expansion construction area and providing a sufficient construction platform for tunnel expansion. At the same time, the force of the upper load was transferred to the portal frame, completing the force conversion of the cross passageway temporary middle partition wall support system;

[0018] 3. By temporarily fixing plates within the platform tunnel, increasing the number of anchor pipes, constructing advance support for the portal at the gantry, and closely reinforcing the portal steel frame, a force system transformation is achieved again, effectively controlling ground subsidence, increasing construction space, and ensuring construction safety.

[0019] 4. After each tunnel is excavated, a support rod is driven in for support. At the same time, after more than two support rods are driven in, the first clamp and the second clamp are connected to the two adjacent support rods respectively so that the adjacent support rods support each other and improve the overall support strength. When the tunnel excavation is completed and all support rods have been driven in, the reinforcing steel bars are connected to all support rods so that all support rods form a whole. Since the reinforcing steel bars can undergo a certain deformation, they can adapt to support rods in different positions and compensate for the errors caused by driving the support rods in. By driving the support rods one by one and finally connecting them into one, it can not only provide real-time support for the tunnel, but also adapt to narrow installation spaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings and examples.

[0021] Figure 1 It is a cross-sectional schematic diagram of the transverse channel and the tunnel in the present invention.

[0022] Figure 2 It is a schematic diagram of the temporary fixing plate and the door frame in the present invention.

[0023] Figure 3 It is a schematic diagram of the joint between the temporary cross passage and the expanded tunnel in the present invention.

[0024] Figure 4 It is a schematic structural diagram of the overall structure of the temporary supporting steel door frame of the partition wall in the transverse passage in the present invention.

[0025] Figure 5 Schematic diagram of a reinforcement member in the present invention.

[0026] In the figure: 1. Support rod; 2. Reinforcement; 21. First clamping jaw; 211. Clamping groove; 212. Locking bolt; 22. Telescopic rod; 221. First rod; 222. Second rod; 223. Locking plate; 224. Locking sleeve; 23. Second clamping jaw; 24. Universal joint; 3. Reinforcement steel bar; 4. Vertical shaft; 41. First bottom seal; 42. Second bottom seal; 43. Third bottom seal; 44. Fourth bottom seal; 51. Upper tunnel of horizontal passage; 52. Middle tunnel of horizontal passage-1; 52. Middle tunnel of horizontal passage-2; 54. Lower tunnel of horizontal passage; 6. Gantry; 61. Support leg; 7. Temporary fixing plate; 8. Tunnel; 81. Expanded tunnel; 82. Shield pipe segment; 83. Closely packed steel frame for expanded tunnel opening; 9. Middle partition wall; 91. Partition. DETAILED DESCRIPTION

[0027] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.

[0028] The invention discloses a construction method for converting a vertical support system at an interface between a transverse passage and an expanded tunnel.

[0029] Reference Figures 1 to 3 A construction method for converting the vertical support system at the interface between a transverse passage and an expanded tunnel comprises the following steps:

[0030] S1. Construct shaft 4 and prepare supporting structures around shaft 4;

[0031] S2. Construction of the upper tunnel 51 of the transverse channel: first, move the construction shaft 4 to the bottom surface of the upper tunnel 51 of the transverse channel to carry out the first temporary bottom sealing, then carry out advance support for the arch of the transverse channel entering the tunnel, and excavate the vertical shaft 4 to a position about 0.3m below the bottom plate of the upper tunnel 51 of the transverse channel, and carry out the second temporary bottom sealing. After that, the enclosure structure of the vertical shaft 4 of the upper tunnel 51 of the transverse channel is chiseled out, and the initial support at the construction opening position is carried out, with three steel frames densely arranged in sequence.

[0032] Then the tunnel 51 on the transverse channel is excavated, and support construction is carried out simultaneously during the excavation, that is, the partition wall 9 and the partition plate 91 are constructed. Finally, the tunnel 51 on the transverse channel is excavated to the position of the transverse channel end wall and the end is sealed.

[0033] S3, construction of the middle tunnel of the transverse passage. The construction of the middle tunnel of the transverse passage was carried out in two steps. First, the vertical shaft 4 was excavated to a position about 0.3m below the bottom plate of the middle tunnel of the transverse passage -152, and the third temporary bottom sealing was carried out.

[0034] Remove the retaining structure of the vertical shaft 4 in the middle tunnel 152 of the transverse passage and construct initial support at the opening location, with three closely spaced steel frames. Then, excavate the middle pilot tunnel 1 of the transverse passage, and simultaneously carry out support construction, namely, construct the intermediate partition wall 9 and partition board 91. Excavate the middle tunnel 152 of the transverse passage to the end wall of the transverse passage and complete the end capping.

[0035] Then follow the above steps to complete the construction of the cross channel middle tunnel-252.

[0036] S4. Shield segment 82 reinforcement, backfilling and demolition construction. Shield segment 82 reinforcement, backfilling and demolition construction are carried out during the construction of the middle tunnel of the cross channel. During construction, the interval segments are first longitudinally tightened, circumferentially supported and partially backfilled and reinforced within the cross channel range. Then, M7.5 mortar is backfilled within 0.5m outside the cross channel excavation contour line and within 1m of the interval end excavation contour line, and backfilled to half the height of the segment.

[0037] Then a breaker hammer is used to break the shield segment 82. The removal of the segments at the intersection of tunnel 8 and the cross channel is carried out simultaneously with the excavation of the cross channel middle tunnel-252. During construction, a temporary support steel frame is used to achieve temporary conversion of the force system. The temporary support steel frame consists of several support rods 1, that is, during the excavation process, the support rods 1 are continuously installed. After the support rods 1 are all installed, reinforcing steel bars 3 are welded on the multiple support rods 1.

[0038] S5. Install the portal frame 6 at the tunnel 8. When constructing the cross channel middle tunnel-252, remove part of the middle partition wall 9 of the cross channel middle tunnel-152 located above the tunnel 8. Then construct a temporary fixing plate 7 in the cross channel middle tunnel-152. The temporary fixing plate 7 is extended with the side wall of the cross channel middle tunnel-152 by using I-shaped steel and longitudinal connecting reinforcement, and is connected to the temporary fixing plate 7 by the cross channel side wall locking anchor pipe within the platform tunnel 8 to improve the safety of force conversion.

[0039] Then the portal frame 6 is installed along the temporary fixing plate 7. When installing the portal frame 6, the top of the portal frame 6 is installed first and concrete is poured. Then excavation is carried out from top to bottom, and the supporting legs 61 of the portal frame 6 are installed in sections during the excavation process, thereby realizing the temporary conversion of the force system again.

[0040] S6: Expand the end of tunnel 8 and build a force system conversion for the cross channel wall based on portal frame 6. At the same time, drive a pipe shed along portal frame 6 to form advanced support for tunnel 8 expansion. Then, construct a dense steel frame 83 for the expanded tunnel portal. Then, weld and spray-mix the cross channel side wall steel frame and the expanded tunnel portal dense steel frame 83 to form a whole. This realizes the force system conversion again, facilitating the expansion of tunnel 8.

[0041] S7. Construction of the pilot tunnel under the transverse channel. When the tunnel 54 under the transverse channel is excavated, the vertical shaft 4 is pulled to a position about 0.3m below the bottom plate of the tunnel 54 under the transverse channel, and the fourth bottom sealing 44 is carried out.

[0042] When the tunnel 54 under the transverse passage is excavated, the shield segments 82 are removed, and the support legs 61 of the portal frame 6 are extended simultaneously, and the support legs 61 and the loose sections of the foundation are backfilled with concrete.

[0043] S8. Expand tunnel 8 to form expanded tunnel 81.

[0044] Reference Figure 4 and Figure 5The temporary support steel frame includes a support rod 1, and multiple support rods 1 are arranged in the horizontal direction. The support rod 1 adopts an I-beam, and the support rod 1 is arranged at an angle. Reinforcement members 2 are provided between adjacent support rods 1 to relatively fix the adjacent support rods 1. The reinforcement member 2 includes a first clamping jaw 21, a telescopic rod 22 and a second clamping jaw 23. The first clamping jaw 21 is suitable for connecting to one support rod 1, and the second clamping jaw 23 is suitable for connecting to another adjacent support rod 1. One end of the telescopic rod 22 is connected to the first clamping jaw 21, and the other end is connected to the second clamping jaw 23. Reinforcement steel bars 3 are also welded between all the support rods 1, and multiple reinforcement steel bars 3 are provided in the vertical direction.

[0045] After each tunnel is excavated, a support rod 1 is driven in for support. At the same time, after more than two support rods 1 are driven in, the first clamp 21 and the second clamp 23 are connected to the two adjacent support rods 1 respectively, so that the adjacent support rods 1 support each other and improve the overall support strength. When the tunnel excavation is completed, all support rods 1 have also been driven in. At this time, the reinforcing steel bars 3 are connected to all support rods 1 so that all support rods 1 form a whole. Since the reinforcing steel bars 3 can undergo a certain deformation, they can adapt to support rods 1 in different positions and compensate for the errors caused by the driving of support rods 1.

[0046] The telescopic rod 22 comprises a first rod 221 and a second rod 222. The first rod 221 extends through the second rod 222, and a locking member is provided on the second rod 222, which is adapted to lock the first and second rods 221 and 222. The first rod 221 is connected to the first clamping jaw 21, while the second rod 222 is connected to the second clamping jaw 23. The locking member comprises a locking piece 223 and a locking sleeve 224. The locking piece 223 is connected to the end surface of the second rod 222 and is provided along the circumference of the second rod 222. The locking pieces 223 are arranged around the first rod 221. The locking sleeve 224 is threadedly connected to the locking pieces 223. The diameter of the locking pieces 223 gradually increases from the second clamping jaw 23 toward the first clamping jaw 21, so that when the locking sleeve 224 is tightened toward the first clamping jaw 21, the first rod 221 is locked.

[0047] A universal joint 24 is connected between the first clamping jaw 21 and the first rod 221, and between the second clamping jaw 23 and the second rod 222. The first clamping jaw 21 and the universal joint 24 are detachably connected by a threaded connection, and the second clamping jaw 23 and the universal joint 24 are detachably connected by a threaded connection.

[0048] The first clamping jaw 21 is provided with a clamping groove 211 for receiving the support rod 1. A locking bolt 212 is threadedly connected to the side wall of the clamping groove 211. The head of the locking bolt 212 abuts against the support rod 1 to lock the support rod 1. The structure of the second clamping jaw 23 is the same as that of the first clamping jaw 21 and will not be repeated here.

[0049] Working principle: After each tunnel is excavated, a support rod 1 is driven in for support. At the same time, after two or more support rods 1 are driven in, the first clamping jaw 21 and the second clamping jaw 23 are respectively connected to the two adjacent support rods 1 so that the adjacent support rods 1 support each other and improve the overall support strength. When the tunnel excavation is completed, all support rods 1 have also been driven in. At this time, the reinforcing steel bars 3 are connected to all support rods 1 so that all support rods 1 form a whole. Since the reinforcing steel bars 3 can undergo a certain deformation, they can adapt to support rods 1 in different positions and compensate for the errors caused by the driving of support rods 1.

[0050] The first clamping jaw 21, the second clamping jaw 23, the first rod 221 and the second rod 222 can be rotated by the universal joint 24 to adapt to the support rod 1 at different positions, thereby facilitating the support rod 1 at different positions.

[0051] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A construction method for converting the vertical support system at the interface between a transverse passage and an expanded tunnel, characterized in that: The steps include: S1, constructing the vertical shaft (4) and building the supporting structure around the vertical shaft (4); S2, construction of the upper pilot hole (51) of the transverse passage; S3. Construction of pilot tunnel in cross passage; S4, reinforcement, backfilling and demolition of shield segments (82). During the reinforcement, backfilling and demolition of shield segments (82), firstly, longitudinal tensioning, circumferential support and backfilling of segments within the cross channel are performed on the interval segments. Then, M7.5 mortar is backfilled within the range of 0.5 m outside the cross channel excavation contour line and within 1 m of the interval end excavation contour line, and backfilled to half the height of the segments. Then, a breaker hammer is used to break the shield segment (82), and the segment removal at the intersection of the tunnel (8) and the cross channel is carried out simultaneously with the excavation of the cross channel middle guide tunnel-2. During the construction, a temporary support steel frame is used to realize the temporary conversion of the force system; The temporary support steel frame includes A support rod (1), wherein a plurality of support rods (1) are provided along the horizontal direction; A reinforcement member (2) is connected to adjacent support rods (1) to relatively fix the adjacent support rods (1), and the reinforcement member (2) includes A first clamping jaw (21) adapted to be connected to a support rod (1); a telescopic rod (22) adapted to be connected to the first clamping jaw (21); A second clamping jaw (23) is connected to an end of the telescopic rod (22) away from the first clamping jaw (21) and is suitable for connecting to another adjacent support rod (1); Reinforcing steel bars (3) connected to all support rods (1); S5, installing the portal frame (6) at the tunnel (8); S6, expand the end of the tunnel (8), and build a cross channel wall force system conversion based on the portal frame (6); S7, construction of pilot tunnel under the cross passage; S8. Expand the tunnel (8).

2. The construction method for converting the vertical support system at the interface between the transverse passage and the expanded tunnel according to claim 1 is characterized in that: During the construction of the upper pilot hole (51) of the transverse channel, the vertical shaft (4) is first constructed to the bottom surface of the upper pilot hole (51) of the transverse channel, and the first temporary bottom sealing is carried out. Then, the cross channel arch is used for advance support of the hole, and the vertical shaft (4) is excavated to a position 0.3m below the bottom plate of the upper pilot hole (51) of the transverse channel, and the second temporary bottom sealing is carried out. After that, the vertical shaft (4) enclosure structure of the upper pilot hole (51) of the transverse channel is removed, and the initial support of the hole opening position is constructed, and three steel frames are arranged closely in sequence. Then the guide hole (51) on the transverse channel is excavated, and the middle partition wall (9) and the partition (91) are constructed synchronously during the excavation. Finally, the guide hole (51) on the transverse channel is excavated to the position of the transverse channel end wall and the end is sealed.

3. The construction method for converting the vertical support system at the interface between the transverse passage and the expanded tunnel according to claim 1 is characterized in that: The construction of the pilot tunnel in the transverse channel is carried out in two steps. First, the vertical shaft (4) is excavated to a position 0.3m below the bottom plate of the pilot tunnel-1 in the transverse channel, and the third temporary bottom sealing is carried out. Remove the enclosure structure of the vertical shaft (4) of the pilot hole-1 in the transverse channel, construct the initial support at the opening position, and sequentially arrange three steel frames closely. Then, excavate the pilot hole-1 in the transverse channel, and simultaneously construct the middle partition wall (9) and partition (91). Install steel frames on the side walls of the transverse channel, excavate the pilot hole-1 in the transverse channel to the position of the transverse channel end wall, and complete the end sealing. Then follow the above steps to complete the construction of the pilot tunnel-2 in the cross channel.

4. The construction method for converting the vertical support system at the interface between the transverse passage and the expanded tunnel as claimed in claim 3 is characterized in that: During the construction of the cross channel middle guide hole-2, part of the middle partition wall (9) of the cross channel middle guide hole-1 located above the tunnel (8) is removed, and then a temporary fixing plate (7) is constructed in the cross channel middle guide hole-1. The temporary fixing plate (7) is connected to the side wall of the cross channel middle guide hole-1 by using I-shaped steel and longitudinal connecting reinforcement, and is densely connected to the temporary fixing plate (7) within the range of the platform tunnel (8) through the cross channel side wall locking anchor pipe, so as to improve the safety of force conversion; Then, the portal frame (6) is installed along the temporary fixing plate (7). When installing the portal frame (6), the top of the portal frame (6) is first installed and concrete is poured. Then, excavation is carried out from top to bottom, and the supporting legs (61) of the portal frame (6) are installed in sections during the excavation process, thereby realizing temporary conversion of the force system again. At the same time, a pipe shed is driven into the portal frame (6) to form an advanced support for the tunnel (8) expansion, and a densely packed steel frame (83) is constructed to expand the tunnel pilot opening. Then, the cross channel side wall steel frame and the densely packed steel frame (83) of the expanded tunnel pilot opening are welded and sprayed to form a whole, thereby realizing the force system conversion again.

5. The construction method for converting the vertical support system at the interface between the transverse passage and the expanded tunnel as claimed in claim 4 is characterized in that: When the lower pilot tunnel (54) of the transverse passage is excavated, the vertical shaft (4) is pulled to a position 0.3 m below the bottom plate of the lower pilot tunnel (54) of the transverse passage, and the fourth bottom sealing (44) is performed; When the guide hole (54) under the transverse channel is excavated, the shield segments (82) are removed and the support legs (61) of the portal frame (6) are extended simultaneously. The support legs (61) and the loose foundation section are backfilled with concrete.

6. The construction method for converting the vertical support system at the interface between the transverse passage and the expanded tunnel as claimed in claim 5 is characterized in that: The telescopic rod (22) comprises a first rod (221) and a second rod (222), wherein the first rod (221) is inserted into the second rod (222), and a locking member is provided on the second rod (222), wherein the locking member is suitable for locking the first rod (221) and the second rod (222); The first rod (221) is connected to the first clamping jaw (21), and the second rod (222) is connected to the second clamping jaw (23).

7. The construction method for converting the vertical support system at the interface between the transverse passage and the expanded tunnel according to claim 6 is characterized in that: The locking member includes a locking piece (223) and a locking sleeve (224). The locking piece (223) is connected to the end surface of the second rod (222) and is provided with a plurality of locking pieces (223) along the circumference of the second rod (222). The plurality of locking pieces (223) are arranged around the first rod (221). The locking sleeve (224) is sleeved on the plurality of locking pieces (223) and is threadedly connected to the locking pieces (223). The diameters of the plurality of locking pieces (223) gradually increase in the direction from the second clamping jaw (23) toward the first clamping jaw (21).

8. The construction method for converting the vertical support system at the interface between the transverse passage and the expanded tunnel as claimed in claim 7 is characterized in that: A universal joint (24) is connected between the first clamping jaw (21) and the first rod (221), and between the second clamping jaw (23) and the second rod (222), respectively.

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