A method for constructing a subway station that is closely attached to an existing tunnel

Abstract

This invention discloses a construction method for subway stations with closely spaced existing tunnels, comprising the following steps: 1. Pre-supporting the area to be excavated. 2. Dividing the area to be excavated into multiple pilot tunnels, prioritizing the construction of pilot tunnels with closely spaced existing tunnels, and then constructing the remaining pilot tunnels at intervals. 3. Excavating the upper step of the pilot tunnel with closely spaced existing tunnels. After excavating one step, temporary support is erected, followed by initial support construction. After the initial support structure is formed, the corresponding lower step is excavated, and temporary support is erected, followed by initial support construction. 4. After the initial support structures of both the upper and lower steps are formed, the temporary support is removed, and secondary lining construction is carried out. 5. Repeating steps 3 and 4, advancing step by step, to complete the construction of the pilot tunnels. 6. Intermittently excavating the remaining pilot tunnels to complete the subway station construction. This invention solves the technical problem of ensuring construction safety and structural safety during the construction of subway stations with closely spaced existing tunnels, which is difficult to achieve with existing construction techniques.

Description

Technical Field

[0001] This invention relates to the field of underground structure construction technology, specifically a method for constructing subway stations that are closely connected to existing tunnels. Background Technology

[0002] To achieve optimal transfer efficiency between new and existing subway lines, a cross-shaped design is often used, where the new station passes under the existing station to minimize transfer distance. However, suitable locations for new stations often have multiple existing tunnels, leading to an increasing number of projects involving overpasses and underpasses of existing lines.

[0003] For construction projects involving close-proximity tunnels under existing structures, the tunnel section must be completed while ensuring the normal operation of the existing line. Therefore, the control of settlement in the existing tunnel is extremely strict, with a basic requirement of keeping settlement within 3mm. For subway station construction that crosses over existing tunnels, the need to excavate the soil layer above the existing structure causes a loss of pressure on the existing structure, which may lead to the uplift of the existing tunnel.

[0004] Current research on closely spaced overpass and underpass projects, both domestically and internationally, mainly focuses on single-condition projects involving closely spaced overpasses or underpasses, with limited research on projects where both the upper and lower structures are closely spaced. Furthermore, closely spaced construction often employs multiple guide holes and small step distances to ensure construction safety, primarily reducing disturbance to the existing structure from the perspective of the new structure, but it cannot actively control disturbances during construction. Another approach involves grouting between the existing structure's base slab and the new structure's top slab to provide a lifting force to the overlying structure, filling gaps caused by incomplete compaction during sealed-space pouring or concrete shrinkage, thereby reducing settlement. Existing grouting methods mainly employ pre-drilled grouting holes or embedded grouting bags. However, the location of cavities caused by concrete shrinkage is difficult to pinpoint, and pre-drilled grouting holes cannot control grout leakage and the grouting effect cannot be guaranteed. Embedded grouting bags can cause separation between the existing and new structures, posing safety hazards and failing to effectively fill shrinkage cavities. Summary of the Invention

[0005] The purpose of this invention is to provide a construction method for subway stations that are closely connected to existing tunnels, which can solve the technical problem that existing construction technologies cannot guarantee construction safety and structural safety during the construction of subway stations that are closely connected to existing tunnels.

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

[0007] A construction method for a subway station that is closely connected to an existing tunnel, comprising the following steps.

[0008] Step 1: Carry out advanced support construction in the area to be excavated.

[0009] Step 2: Divide the area to be excavated into multiple pilot tunnels. Prioritize the construction of pilot tunnels that are closely attached to the existing tunnels both above and below, and construct the remaining pilot tunnels at intervals.

[0010] Step 3: Excavate the upper bench that is closely attached to the existing tunnel guide tunnel. After excavating one step, erect temporary support. After the temporary support is erected, the initial support construction will begin immediately. After the initial support structure of the upper bench is formed, excavate the corresponding lower bench. After the excavation is in place, erect temporary support. After the temporary support is erected, the initial support construction will begin immediately.

[0011] Step 4: After the initial support structures of the upper and lower steps in a step distance are formed, remove the temporary supports and carry out the secondary lining construction for that step distance.

[0012] Step 5: Repeat steps 3 and 4 above, advancing step by step, to complete the excavation, initial support and secondary lining construction of the existing tunnel guide tunnel that is closely attached to both the top and bottom.

[0013] Step 6: Excavate the remaining pilot tunnels at intervals to complete the construction of the subway station that is closely connected to the existing tunnel.

[0014] Furthermore, in step three, after the upper step is excavated to the desired position, an arch foot groove is excavated at the bottom of the sidewall along the tunnel length direction. The arch foot groove is cleaned and reinforced. An upper step support plate, an arch top support plate, and support rods for temporary support are installed. The lower part of the upper step support plate has a protrusion that is embedded in the arch foot groove. One end of the support rod is connected to the inner side of the protrusion, and the other end is connected to the bottom of the arch top support plate. This is used to simultaneously provide upward support force to the arch top support plate and pressure to the tunnel sidewall provided by the upper step support plate. The temporary support of the upper step is then completed.

[0015] After the lower step is excavated, the arch foot is cleaned and reinforced. Lower step support plates and support rods are installed for temporary support. The lower step support plates are L-shaped, and two lower step support plates are set opposite each other for temporary support of the lower step. One end of the support rod in the lower step is connected to the connection point on the support rod in the upper step, and the other end is connected to the corner of the lower step support plate to apply downward and guide tunnel sidewall pressure to the lower step support plate.

[0016] Furthermore, the length of the support rod is adjustable. The support rod includes a support part and an adjustment part. The two ends of the adjustment part are provided with threads of opposite directions. The two support parts are respectively engaged with the two ends of the adjustment part through threads. Rotating the adjustment part can make the two support parts move closer or further away from each other to shorten or lengthen the support rod. The end of the support part is provided with a hinge hole for connecting with the support plate.

[0017] Furthermore, the support part is provided with a locking structure for locking the support part and the adjustment part. The locking structure includes a tapered threaded clamp and a locking nut located at one end of the support part near the adjustment part. The support part is provided with a tapered thread at one end near the adjustment part, and multiple slots are provided circumferentially at the location where the tapered thread is provided to form multiple tapered threaded clamps. Rotating the locking nut can cause the tapered threaded clamp to clamp the adjustment part, thereby locking the support part and the adjustment part.

[0018] Furthermore, in step three, when constructing the initial support structure for the upper step, rubber bags are first placed on the top of the guide tunnel before the initial support structure is constructed.

[0019] Furthermore, the rubber bladder is provided with a sealed grouting port that can be broken open under certain pressure, and a rigid grouting pipe is inserted inside the rubber bladder, with grouting ports evenly distributed on the grouting pipe.

[0020] Furthermore, in step five, after the secondary lining of the existing tunnel guide tunnel is tightly attached to both the top and bottom, grout is injected into the pre-embedded rubber bag through a rigid grouting pipe to fill the gap between the new structure and the bottom of the existing tunnel above, so that the new structure and the existing tunnel above are solidified into an integral structure through grout.

[0021] Furthermore, in step six, when excavating the remaining pilot tunnels, the upper step of the pilot tunnel is excavated first. After excavating one step distance, temporary support is erected. After the temporary support is erected, the initial support construction is carried out immediately. After the initial support structure of the upper step is formed, the corresponding lower step is excavated. After the excavation is in place, temporary support is erected. After the temporary support is erected, the initial support construction is carried out immediately. After the initial support structure is formed, the temporary support is removed, and the secondary lining construction of that step distance is carried out. The construction is advanced step by step to complete the construction of the corresponding pilot tunnel.

[0022] Furthermore, since there are no existing tunnels below the remaining pilot tunnels, the temporary support adopts a normal vertical arch frame or jack structure.

[0023] Furthermore, in step six, after the secondary lining structure strength of the previous batch of pilot tunnels reaches 80%, the construction of the next batch of pilot tunnels will begin.

[0024] By adopting the above technical solution, the present invention has the following beneficial effects:

[0025] 1. The present invention prioritizes excavating a pilot tunnel that is closely attached to the existing tunnel from top to bottom. At this time, the soil is not disturbed and is in a safe state. Furthermore, after the pilot tunnel is excavated, the surrounding rock can serve as a load-bearing structure, providing conditions for the installation of the support structure.

[0026] 2. The pilot tunnel is excavated in stages, with upper and lower steps, and temporary support and initial support are carried out in a timely manner to further reduce the disturbance to the surrounding soil and existing structure caused by the excavation.

[0027] 3. The present invention uses support plates and support rods as temporary support structures, both of which can be prefabricated in the factory and assembled on site, making construction convenient, safe and quick; the support rods adopt a telescopic design, which can actively control the settlement of the existing structure above and transfer some of the pressure to the existing tunnel below, which can effectively prevent the existing tunnel below from floating; the support rods are connected to the support plates by high-strength bolts, which are convenient for installation and dismantling and can be recycled.

[0028] 4. Using support plates and support rods as temporary supports, the existing tunnel structure below is not directly subjected to force, avoiding potential damage to the existing structure during construction. The inclined setting of the support rods from the arch crown to the arch foot can minimize the occupation of construction space.

[0029] 5. Grouting bags are installed between the initial support structure of the pilot tunnel and the existing tunnel above. After the secondary lining structure is completed, grout is injected into the gap between the new structure and the existing structure. Grouting can also actively control the settlement of the existing structure above. Grouting makes the new structure and the existing structure form a whole, improving the safety of the overall structure. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of dividing the area to be excavated into multiple pilot tunnels in this invention.

[0031] Figure 2 This is a schematic diagram showing the location of the pilot tunnel that is preferentially constructed in this invention, with both the upper and lower sections closely attached to the existing tunnel.

[0032] Figure 3 This is a schematic diagram showing the state of the first batch of construction pilot tunnels in the intermittent excavation of the remaining pilot tunnels in this invention.

[0033] Figure 4 This is a schematic diagram showing the status of the second batch of construction pilot tunnels in the intermittent excavation of the remaining pilot tunnels in this invention.

[0034] Figure 5 This is a schematic diagram of the state of the excavation of the upper step of the existing tunnel guide tunnel, which is closely attached to both the top and bottom of the present invention.

[0035] Figure 6 This is a schematic diagram of the arch foot groove of the existing tunnel guide tunnel, which is tightly attached to both the top and bottom.

[0036] Figure 7 This is a schematic diagram of the overall structure of the temporary support for the upper step of the existing tunnel guide tunnel in this invention, which is closely attached to both the top and bottom.

[0037] Figure 8 This is a schematic diagram of the state in which the upper and lower parts of the existing tunnel guide tunnel are closely attached to the lower step during excavation in this invention.

[0038] Figure 9This is a schematic diagram of the overall structure of the temporary support for the lower step of the existing tunnel guide tunnel, which is closely attached to both the top and bottom of the tunnel in this invention.

[0039] Figure 10 yes Figure 9 Enlarged diagram of point A in the middle.

[0040] Figure 11 This is a schematic diagram of the overall structure of the support rod in this invention.

[0041] Figure 12 This is an enlarged schematic diagram of the support rod locking structure in this invention.

[0042] Attached diagram descriptions: 1. Existing tunnel; 2. New structure; 21. Existing tunnel guide tunnels closely attached to both the top and bottom; 22. Other guide tunnels; 3. Upper step; 31. Arch foot groove; 4. Lower step; 51. Upper step support plate; 52. Arch top support plate; 53. Lower step support plate; 6. Support rod; 61. Support part; 62. Adjustment part; 63. Tapered threaded clamp; 64. Locking nut. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the features and performance of a subway station construction method for closely adjacent to an existing tunnel according to the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0044] Example 1

[0045] Please see the appendix Figures 1-12 A method for constructing subway stations that are closely integrated with existing tunnels, comprising the following steps.

[0046] Step 1: Conduct advanced support construction in the area to be excavated. Considering that the new tunnel is closely adjacent to the existing tunnel above and below, large pipe roofs and full-section grouting can be used to reinforce the soil in front of the excavation.

[0047] Step 2: Divide the area to be excavated into multiple pilot tunnels. Prioritize the construction of pilot tunnel 21, which is closely attached to the existing tunnel both above and below. The remaining pilot tunnels will be constructed at intervals.

[0048] like Figures 1-4 As shown, the area to be excavated is divided into multiple pilot tunnel locations. First, the pilot tunnel 21, which is closely connected to the existing tunnel above and below, is excavated, i.e., the pilot tunnel in area I. Then, the pilot tunnel in area II is excavated at intervals. After the secondary lining structure strength of the pilot tunnel in area II reaches 80%, the pilot tunnel in area III is finally excavated.

[0049] Step 3, as follows Figure 5 As shown, the excavation closely follows the upper step 3 of the existing tunnel guide tunnel 21 both above and below. After excavating one step distance, an arch foot groove 31 is excavated at the bottom of the sidewall along the tunnel length direction, as shown. Figure 6As shown, the arch foot groove 31 is cleaned and reinforced. The length of each step is determined according to factors such as project scale and terrain structure. Preferably, in this embodiment, each step is set to 0.5 meters.

[0050] like Figure 7 As shown, after the upper step 3 is excavated to its position, temporary support is erected, and upper step support plate 51, arch support plate 52, and support rod 6 are installed for temporary support. The lower part of the upper step support plate 51 has a protrusion that is embedded in the arch foot groove 31. One end of the support rod 6 is connected to the inner side of the protrusion, and the other end is connected to the bottom of the arch support plate 52. This is used to simultaneously provide upward support force to the arch support plate 52 and pressure to the guide tunnel sidewall from the upper step support plate 51. The temporary support for the upper step 3 is then completed. After the temporary support is erected, the initial support construction is carried out immediately. During the initial support construction of the upper step 3, rubber bags are first placed at the top of the guide tunnel, and then the initial support structure is constructed. The rubber bags are equipped with closed grouting ports that can be broken under certain pressure. Rigid grouting pipes are inserted inside the rubber bags, and grouting ports are evenly distributed on the grouting pipes.

[0051] After the initial support structure of the upper step 3 is formed, the corresponding lower step 4 is excavated. After the lower step 4 is excavated, the arch foot is cleaned and reinforced, as follows: Figure 8 As shown.

[0052] like Figure 9 As shown, after the lower step 4 is excavated to its position, temporary support is erected, and lower step support plates 53 and support rods 6 are installed for temporary support. The lower step support plates 53 are L-shaped, and two lower step support plates 53 are set opposite each other for temporary support of the lower step 4. One end of the support rod 6 in the lower step 4 is connected to the connection point on the support rod 6 in the upper step 3, and the other end is connected to the corner of the lower step support plate 53. This is used to apply downward and guide tunnel sidewall pressure to the lower step support plate 53 to prevent the existing tunnel below from floating due to the unloading of earthwork excavation. After the temporary support is erected, the initial support construction is carried out immediately.

[0053] When the existing tunnel guide tunnel 21 is excavated, the excavated sidewall is not vertical, but rather arc-shaped towards the surrounding rock. This shape can better distribute the pressure of the upper support structure to the sidewall surrounding rock.

[0054] The length of the aforementioned support rod 6 is adjustable, such as... Figure 11 As shown, the support rod 6 includes a support part 61 and an adjustment part 62. The two ends of the adjustment part 62 are provided with threads with opposite directions of rotation. The two support parts 61 are respectively engaged with the two ends of the adjustment part 62 through threads. Rotating the adjustment part 62 can make the two support parts 61 move closer or further away from each other to shorten or lengthen the support rod 6. The end of the support part 61 is provided with a hinge hole for connecting with the support plate.

[0055] like Figure 12As shown, the support part 61 is also provided with a locking structure for locking the support part 61 and the adjustment part 62. The locking structure includes a tapered threaded clamp 63 and a locking nut 64 located at one end of the support part 61 near the adjustment part 62. The support part 61 has a tapered thread at one end near the adjustment part 62, and multiple slots are provided circumferentially at the location where the tapered thread is located to form multiple tapered threaded clamps 63. Rotating the locking nut 64 can cause the tapered threaded clamps 63 to clamp the adjustment part 62, thereby locking the support part 61 and the adjustment part 62.

[0056] When using the support rod 6 to support the support plate, rotate the adjusting part 62 to adjust the length of the support rod 6, so that its two ends are connected to the connecting members set at corresponding positions on the support plate through high-strength bolts. Continue to rotate the adjusting part 62 to extend the support rod 6, pressing the support plates at both ends tightly onto the corresponding support surfaces. When the supporting force reaches the predetermined value by rotating the adjusting part 62, rotate the locking nut 64 to clamp the adjusting part 62 with the tapered threaded clamp 63, thereby locking the length of the support rod 6.

[0057] The initial support structure construction includes erecting I-beams, hanging wire mesh, and spraying concrete. The I-beams can be set up close to the temporary support structure. After the initial support is formed, the main support structure is transferred from the temporary support structure to the initial support structure.

[0058] Step 4: After the initial support structures of the upper and lower steps in a step distance are formed, remove the temporary supports and carry out the secondary lining construction for that step distance.

[0059] Step 5: Repeat steps 3 and 4 above, advancing step by step, to complete the excavation, initial support and secondary lining construction of the existing tunnel guide tunnel 21, which is closely attached to both the upper and lower sides.

[0060] After the secondary lining of the existing tunnel guide tunnel 21 is completed and tightly attached to both the top and bottom, grout is injected into the pre-embedded rubber bag through a rigid grouting pipe. The grout flows along the rigid grouting pipe and enters the rubber bag through the grouting port on the rigid grouting pipe. When there is a cavity between the bottom of the existing tunnel above and the top slab of the new station, the closed grouting hole on the rubber bag located at the cavity position breaks open under pressure, and the grout flows into the cavity to compact it, thus solidifying the new station and the tunnel above into an integral structure through the grout.

[0061] Alternatively, by monitoring the settlement of the tunnel above, if the settlement at a certain location becomes too large, grouting can be injected into the rubber bags to raise the tunnel above.

[0062] Step Six: Excavate the remaining pilot tunnels at intervals to complete the construction of the subway station, which is closely connected to the existing tunnel. (For example...) Figures 3-4As shown, the pilot tunnel in area I has been excavated. The remaining pilot tunnels will be excavated first in area II. After the secondary lining structure strength of the previous batch of pilot tunnels reaches 80%, the construction of the next batch of pilot tunnels, namely the pilot tunnels in area III, will begin.

[0063] When excavating the remaining pilot tunnels, the upper step 3 of the pilot tunnel is excavated first. After excavating one step distance, temporary support is erected. After the temporary support is erected, the initial support construction is carried out immediately. After the initial support structure of the upper step 3 is formed, the corresponding lower step 4 is excavated. After the excavation is in place, temporary support is erected. After the temporary support is erected, the initial support construction is carried out immediately. After the initial support structure is formed, the temporary support is removed, and the secondary lining construction of that step distance is carried out. The construction is carried out step by step to complete the construction of the corresponding pilot tunnel.

[0064] In particular, since there are no existing tunnels below the other pilot tunnels, the temporary support adopts the normal vertical arch frame or jack structure.

[0065] Example 2

[0066] Unlike Embodiment 1, in Embodiment 2, there are multiple existing tunnels below the newly constructed structure 2. After the excavation of the pilot tunnels that are closely adjacent to the existing tunnels above and below is completed, the pilot tunnels that are closely adjacent to the existing tunnels below are excavated first when the remaining pilot tunnels are excavated at intervals.

[0067] The method and steps for excavating the pilot tunnel below closely attached to the existing tunnel are the same as those for excavating the pilot tunnels above and below closely attached to the existing tunnel. Support plates and support rods are also used to form temporary support to avoid damage to the existing tunnel structure below.

[0068] It should be noted that the parts not described in detail in this solution are all prior art. The above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for constructing a subway station that is closely connected to an existing tunnel, characterized in that: Includes the following steps, Step 1: Conduct advanced support construction for the area to be excavated; Step 2: Divide the area to be excavated into multiple pilot tunnels, prioritize the construction of the existing tunnel pilot tunnels that are closely attached to the upper and lower sides (21), and construct the remaining pilot tunnels at intervals; Step 3: Excavate the upper step (3) that is closely attached to the existing tunnel guide tunnel (21) at both the top and bottom. After excavating one step distance, excavate the arch foot groove (31) at the bottom of the sidewall along the tunnel length direction. Clean and reinforce the arch foot groove (31). Install the upper step support plate (51), the arch top support plate (52), and the support rod (6) for temporary support. The lower part of the upper step support plate (51) is provided with a protrusion that is embedded in the arch foot groove (31). One end of the support rod (6) is connected to the inner side of the protrusion, and the other end is connected to the bottom of the arch top support plate (52). It is used to simultaneously provide upward support force to the arch top support plate (52) and pressure to the guide tunnel sidewall to the upper step support plate (51). The temporary support of the upper step (3) is completed. After the temporary support is completed, the initial support construction is carried out. After the initial support structure of the upper step (3) is formed, the corresponding lower step (4) is excavated. After the lower step (4) is excavated, the arch foot is cleaned and reinforced. The lower step support plate (53) and support rod (6) for temporary support are installed. The lower step support plate (53) is L-shaped. The two lower step support plates (53) are set opposite each other for temporary support of the lower step (4). One end of the support rod (6) in the lower step (4) is connected to the connection point on the support rod (6) in the upper step (3), and the other end is connected to the corner of the lower step support plate (53) to apply downward and guide tunnel sidewall pressure to the lower step support plate (53). After the temporary support is completed, the initial support construction is carried out. Step 4: After the initial support structure of the upper and lower steps in a step distance is completed, remove the temporary support and carry out the secondary lining construction for that step distance. Step 5: Repeat steps 3 and 4 above, advancing step by step, to complete the excavation, initial support and secondary lining construction of the existing tunnel guide tunnel (21) which is closely attached to both the upper and lower sides; Step 6: Excavate the remaining pilot tunnels at intervals to complete the construction of the subway station that is closely connected to the existing tunnel.

2. The construction method for a subway station that is closely connected to an existing tunnel as described in claim 1, characterized in that: The length of the support rod (6) is adjustable. The support rod (6) includes a support part (61) and an adjustment part (62). The two ends of the adjustment part (62) are provided with threads with opposite directions. The two support parts (61) are respectively engaged with the two ends of the adjustment part (62) by threads. Rotating the adjustment part (62) can make the two support parts (61) move closer or further away from each other to shorten or lengthen the support rod (6). The end of the support part (61) is provided with a hinge hole for connecting with the support plate.

3. The construction method for a subway station that is closely connected to an existing tunnel as described in claim 2, characterized in that: The support part (61) is provided with a locking structure for locking the support part (61) and the adjustment part (62). The locking structure includes a tapered threaded clip (63) and a locking nut (64) located at one end of the support part (61) near the adjustment part (62). The support part (61) is provided with a tapered thread at one end near the adjustment part (62), and multiple slots are provided circumferentially at the location where the tapered thread is provided to form multiple tapered threaded clips (63). Rotating the locking nut (64) can cause the tapered threaded clips (63) to clamp the adjustment part (62) to achieve locking of the support part (61) and the adjustment part (62).

4. The construction method for a subway station that is closely connected to an existing tunnel as described in claim 1, characterized in that: In step three, when constructing the initial support of the upper step (3), rubber bags are first placed on the top of the guide tunnel before the construction of the initial support structure is carried out.

5. A method for constructing a subway station that is closely connected to an existing tunnel, as described in claim 4, characterized in that: The rubber bladder has a sealed grouting port that can be broken open under certain pressure. A rigid grouting pipe is inserted inside the rubber bladder, and grouting ports are evenly distributed on the grouting pipe.

6. The construction method for a subway station that is closely connected to an existing tunnel as described in claim 5, characterized in that: In step five, after the secondary lining of the existing tunnel guide tunnel (21) is tightly attached to both the top and bottom, grout is injected into the pre-embedded rubber bag through a rigid grouting pipe to fill the gap between the new structure and the bottom of the existing tunnel above, so that the new structure and the existing tunnel above are solidified into an integral structure through grout.

7. The construction method for a subway station that is closely connected to an existing tunnel as described in claim 1, characterized in that: In step six, when excavating the remaining pilot tunnels, the upper step (3) of the pilot tunnel is excavated first. After excavating one step distance, temporary support is erected. After the temporary support is erected, the initial support construction is carried out. After the initial support structure of the upper step (3) is formed, the corresponding lower step (4) is excavated. After the excavation is in place, temporary support is erected. After the temporary support is erected, the initial support construction is carried out. After the initial support structure is formed, the temporary support is removed, and the secondary lining construction of that step distance is carried out. The construction of the corresponding pilot tunnel is completed step by step.

8. A method for constructing a subway station that is closely connected to an existing tunnel, as described in claim 7, characterized in that: Since there are no existing tunnels below the remaining pilot tunnels, the temporary support adopts the normal vertical arch frame or jack structure.

9. A method for constructing a subway station that is closely connected to an existing tunnel, as described in claim 1, characterized in that: In step six, after the secondary lining structure strength of the previous batch of pilot tunnels reaches 80%, the construction of the next batch of pilot tunnels will begin.

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