Method for hoisting out shield machine above existing underground structure

Abstract

The present invention discloses a method for hoisting a shield machine above an existing underground structure, and the method includes the following steps: S1, presetting a hoisting hole; S2, analyzing and confirming whether reinforcement is required; before reinforcement, using numerical simulation modeling, comparing the numerical changes of the existing structure with its bearing limit from three aspects: the vertical displacement of the top plate and the beam, the vertical displacement of the frame column, and the stress of the top beam, to confirm whether reinforcement is required; S3, selecting a fire escape passage; S4, selecting the position of the lifting vehicle and the transport vehicle; S5, selecting the route of pedestrians and other vehicles; S6, hoisting construction. The hoisting method of the present invention analyzes the existing ground structure near the reserved hoisting hole, and after numerical simulation comparative analysis, selects a reinforcement method for overall assembly and reinforcement. The hoisting is convenient to install and disassemble. The scaffolding is supported and fixed by I-beams and columns, which is easy to adjust and has stable support. The position routes of various parts in the hoisting process do not interfere with each other. The hoisting process is safe and stable, and the construction efficiency is high.

Description

Technical Field

[0001] The invention relates to the technical field of shield machine hoisting, in particular to a method for hoisting a shield machine above an existing underground structure. Background Art

[0002] Shield machines are expensive, large, and heavy. Hoisting the shield machine into and out of the launch shaft requires significant space at the construction site and significantly disturbs surrounding structures. Therefore, hoisting the shield machine into and out of the shaft requires high technical requirements and a comprehensive hoisting plan, including considerations such as whether the structure requires pre-existing hoisting holes, the selection of hoisting equipment, the positioning of the crane, and the selection of transport vehicle routes. Currently, two methods are used for hoisting shield machines: integral hoisting and split hoisting. Split hoisting involves hoisting the shield machine into the shaft individually into the launch shaft and then assembling it. Before hoisting it out of the shaft, the shield machine is disassembled into its individual components within the launch shaft and then hoisted out one by one. While this process is time-consuming and labor-intensive, it requires relatively little space, generates correspondingly lower hoisting loads, and is relatively safe and reliable. Therefore, split hoisting is more commonly used in actual shield installation projects.

[0003] During hoisting, the shield machine and lifting equipment are heavy, generating excessive loads on the work surface. In most cases, the shield machine's launch and receiving shafts are surrounded by urban pavement with good bearing capacity. The soil and hardened pavement at the shield hoisting construction site can directly serve as the bearing layer, requiring no foundation treatment or minimal treatment to meet the foundation bearing capacity requirements for shield machine installation. Research has been conducted on the impact of shield hoisting on soil and hardened pavement on construction sites. However, in some subway projects, the shield machine's launch and receiving shafts are not surrounded by soil and pavement with good bearing capacity, but by existing underground concrete structures. The shield hoisting construction site is located above existing underground concrete structures.

[0004] When hoisting over existing concrete structures, the load often causes unpredictable structural damage to both the ground and underground structures. Therefore, the question of how to analyze the structure, how to reinforce the underground structure, and which hoisting method to use for shield installation have become pressing issues for shield hoisting over existing structures.

[0005] The traditional solution of using steel pipes to reinforce the hoisting ground is difficult to connect and install during actual construction. The transportation of large quantities of steel pipes is time-consuming and labor-intensive, and the disassembly is inconvenient. There is often a gap between the support process and the ground, making it impossible to provide good support. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for hoisting a shield machine above an existing underground structure. The existing ground structure near the reserved hoisting hole is analyzed. After numerical simulation and comparative analysis, a scaffolding is selected for overall assembly and reinforcement. The scaffolding is easy to install and disassemble. The scaffolding is supported and fixed with I-beams and columns. The adjustment is convenient and the support is stable. The position routes of various parts during the hoisting process do not interfere with each other. The hoisting process is safe and stable, the construction efficiency is high, and the damage to the existing ground structure is reduced.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A method for hoisting a shield machine above an existing underground structure, the method comprising the following steps:

[0009] S1. Preset lifting holes.

[0010] S2. Analyze and confirm whether reinforcement is required.

[0011] Before reinforcement, numerical simulation modeling is used to compare the numerical changes of the existing structure with its bearing limits from three aspects: the vertical displacement of the top plate and beam, the vertical displacement of the frame column, and the stress of the top beam, to confirm whether reinforcement is needed.

[0012] S3. Fire escape route selection.

[0013] S4. Selection of positions for lifting vehicles and transport vehicles.

[0014] S5. Route selection for pedestrians and other vehicles.

[0015] S6. Hoisting construction.

[0016] Furthermore, the S1 includes reserving a hoisting hole on the original structure and laying a pre-installed cover plate on the hoisting hole.

[0017] Furthermore, the reinforcement method of S2 is scaffolding reinforcement.

[0018] Furthermore, the scaffolding includes vertical poles, horizontal poles are connected on both sides of the vertical poles, screws are rotatably provided on the vertical poles, adjusting nuts are fastened on the vertical poles, adjustable supports are fastened on the tops of the vertical poles, and I-beams for supporting the ground structure are connected to the adjustable supports, and the I-beams on each vertical pole are fastened to each other.

[0019] Furthermore, the adjusting nut cooperates with the screw rod.

[0020] Furthermore, the S4 includes setting up stations for transport vehicles and lifting vehicles near the lifting port, which are separated from the fire passage, pedestrian and other vehicle routes. The lifting vehicle is set at a reinforced ground location, and a steel plate is provided at the bottom of the lifting vehicle. The transport route of the transport vehicle is selected at a location where the vertical displacement between the top plate and the beam is small.

[0021] Furthermore, the S6 includes splitting the shield machine into parts, and then hoisting the parts of the shield machine onto a transport vehicle in sequence for transportation.

[0022] Beneficial effects of the present invention:

[0023] 1. The hoisting method of the present invention analyzes the existing ground structure near the reserved hoisting hole. After numerical simulation and comparative analysis, scaffolding is selected for overall assembly and reinforcement. It is easy to install and disassemble. The scaffolding uses I-beams and columns for support and fixation, which is easy to adjust and provides stable support.

[0024] 2. In the hoisting method of the present invention, the positions and routes of the various parts during the hoisting process do not interfere with each other, the hoisting process is safe and stable, the construction efficiency is high, and the damage to the existing ground structure is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] Figure 1 It is a schematic diagram of the structure of the structural modeling model of the present invention;

[0027] Figure 2 It is a schematic diagram of the load arrangement of the left side hoisting model of the present invention;

[0028] Figure 3 It is a schematic diagram of the load arrangement of the right side hoisting model of the present invention;

[0029] Figure 4 is a schematic diagram of the ground model coordinate system of the present invention;

[0030] Figure 5 It is a schematic diagram of the vertical displacement of the left side hoisting top plate of the present invention;

[0031] Figure 6 It is a schematic diagram of the arrangement of the frame columns of the present invention;

[0032] Figure 7 It is a schematic diagram of the vertical displacement of the top of the left side hoisting frame column of the present invention;

[0033] Figure 8 It is a schematic diagram of the left side hoisting crack width of the present invention;

[0034] Figure 9 This is the displacement cloud diagram of the left side hoisting top beam of the present invention;

[0035] Figure 10 It is a schematic diagram of the scaffold reinforcement position structure of the present invention;

[0036] Figure 11 It is a schematic diagram of the scaffold column structure of the present invention;

[0037] Figure 12 This is a diagram of the vertical displacement of the left hoisting top plate after reinforcement according to the present invention;

[0038] Figure 13 This is a comparison diagram of the vertical displacement of the left side hoisting path 1 of the present invention and the unreinforced one;

[0039] Figure 14 This is a schematic diagram of the positions of the left and right hoisting vehicles of the present invention;

[0040] Figure 15 This is a schematic diagram of the position and transportation route of the left-side lifting and transportation vehicle of the present invention;

[0041] Figure 16 It is the vertical displacement diagram of the right side hoisting top plate of the present invention;

[0042] Figure 17 This is a vertical displacement diagram of the top of the right-side hoisting frame column of the present invention;

[0043] Figure 18 This is the displacement cloud diagram of the right side hoisting crack width of the present invention;

[0044] Figure 19 This is a comparison diagram of the vertical displacement of path 2 after hoisting on the right side of the present invention and that of the unreinforced one;

[0045] Figure 20 This is the displacement cloud diagram of the right side hoisting top beam of the present invention;

[0046] Figure 21 It is a schematic diagram of the position and transportation route of the lifting and transporting vehicle on the right side of the present invention. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0048] Example 1

[0049] A method for hoisting a shield machine above an existing underground structure includes the following steps:

[0050] S1, preset lifting hole

[0051] Reserve lifting holes on the original structure, lay pre-installed covers on the lifting holes, and remove the lifting covers during lifting.

[0052] Taking the railway station square as an example, before the construction of the station, the location and number of hoisting holes for the shield machine hoisting construction during the later subway construction should be planned, and the shield hoisting holes should be reserved during the construction of the station.

[0053] S2. Underground structure reinforcement analysis

[0054] like Figure 1 As shown, the station concourse hoisting area is assumed to be a concrete frame structure, covered with planting soil and a hardened concrete layer. When the shield machine is hoisted in the concourse, the heavy weight of the hoisting machinery and shield machine will cause deformation of the underground structure, endangering operational safety. The finite element method is used to analyze the ground surface and determine whether reinforcement is necessary. The finite element method idealizes a continuum with infinite degrees of freedom into a collection of elements with finite degrees of freedom, then uses numerical analysis to perform approximate calculations.

[0055] like Figure 2 As shown in the figure, the station square is modeled. According to the basic principles and methods of finite element analysis, the soil is approximately considered as a uniform continuous medium during calculation. In the actual modeling process, three-dimensional isoparametric units are used for simulation, among which the structural units only consider their elastic working state.

[0056] like Figure 3 、 Figure 4 As shown, the station square load includes the weight of the crane, the shield machine, and the transport vehicle load. To account for dynamic loads, wind loads, hoisting equipment mass, and personnel activity during actual hoisting operations, the hoisting load is magnified by a factor of 1.3, and the loads are divided into three categories: hoisting load, transport load, and personnel load. A 30mm-40mm thick steel plate is laid under the crane.

[0057] like Figure 1 、 Figure 4 As shown, a coordinate system is established, and the left and right surfaces are constrained in the X direction; the top is a free surface, the bottom is constrained in the Z direction, and the front and back surfaces are constrained in the Y direction.

[0058] The present invention adopts static analysis and sets four working conditions.

[0059] Working condition 1: Hoisting on the left side without reinforcement;

[0060] 1. Vertical displacement of top plate and beam

[0061] like Figure 5 As shown in the figure, when the left opening was hoisted, the maximum vertical displacement and deflection of the top plate was 0.55mm, and the minimum was -7.31mm.

[0062] Depend on Figure 5 Analysis shows that the vertical displacement and deflection of the top plate and beam are in the range of -7.3 mm to 0.55 mm. When the vertical displacement of the top plate and beam approaches or exceeds the limit, reinforcement treatment is carried out.

[0063] Calculate the vertical displacement of the frame column. To facilitate the analysis, the frame column is set as follows: Figure 6 As shown, each row is numbered from left to right.

[0064] like Figure 7 As shown in the figure, when the left opening is hoisted, the maximum vertical displacement of the top of the frame column is 0.48mm and the minimum is -2.26mm.

[0065] from Figure 7 From the analysis, it can be seen that the vertical displacement and deflection of the top plate and beam are in the range of -2.26mm to 0.48mm, and the vertical displacement of the top of 2% of the columns is above 1mm. When the maximum vertical displacement approaches or exceeds the limit, reinforcement treatment is carried out.

[0066] Table 1 Vertical displacement of the top of each column on the left side (unit: mm)

[0067]

[0068] 2. Calculate the width of the roof crack

[0069] When hoisting on the left side, the width of the crack on the top plate is as follows: Figure 8 As shown, the cracks are densely distributed near the lifting port and at the junction of the beam and slab. After querying the structure table file, it can be seen that the maximum crack width during the left lifting is at unit 239675, and the unit location is Figure 8 The maximum crack width is 0.589 mm, which is marked with dots and exceeds the crack limit of 0.2 mm specified in the design of the structure.

[0070] 3. Calculate the top beam stress

[0071] When hoisting on the left side, the stress cloud diagram of the top beam is as follows Figure 9 As shown in the displacement cloud, the stress values ​​of the top beam ranged from 0.071 to 64.664 MPa during left-side hoisting. The concrete grade used in the top beam is C40, and the standard uniaxial compressive strength of C40 concrete is 26.8 MPa. During both left and right-side hoisting, the maximum stress values ​​of the top beam exceeded this value. When the maximum stress value of the top beam approaches or exceeds the limit, reinforcement is performed.

[0072] 4. Reinforcement

[0073] The disc-type scaffolding reinforcement scheme is adopted, that is, the disc-type scaffolding with a spacing of 1.2*1.2m is arranged to reinforce the structure, and the 300*300mm spacing is used within the two spans on the north side of the lifting port. Figure 10The location selected in the middle box. Each upright is in contact with the upper building structure at that location, and scaffolding supports the main and secondary beams. The scaffolding was modeled using one-dimensional linear elements with a wall thickness of 3.2 mm and an outer diameter of 63 mm.

[0074] like Figure 11 As shown, the structural system of the scaffolding should be complete and the scaffolding should have overall stability; the scaffolding includes vertical poles 4, and horizontal poles 5 are connected to both sides of the vertical poles 4. Screw rods 2 are rotatably provided on the vertical poles 4, and adjusting nuts 3 are fastened on the vertical poles 4. The adjusting nuts 3 cooperate with the screw rods 2 to fix the screw rods 2. The arrangement height of the sweeping rods is 200mm; oblique rods are provided between the sweeping rods to support and fix the sweeping rods; an adjustable support 1 is fastened to the top of the vertical pole 4, and the adjustable support 1 is connected to For I-beams, adjust the adjustable support 1 to move upwards, support the I-beam to fit tightly against the building structure, support and reinforce the building structure, and tighten the I-beams on each vertical pole 4; when erecting, adjust the screw 2 on the vertical pole 4, the cantilever length of the adjustable support 1 extending out of the horizontal pole 5 or the center line of the double-slot joist should not exceed 650mm, and the exposed length of the thread on the screw 2 should not exceed 400mm, and the length of the adjustable support 1 inserted into the vertical pole 4 or the double-slot joist shall not be less than 150mm.

[0075] Working condition 2: hoisting on the left side after reinforcement;

[0076] Calculate the vertical displacement of the top plate and beams. After reinforcement, when the left side opening is hoisted, the vertical displacement of the top plate is as follows: Figure 12 As shown in the figure, the maximum value is 0.42mm and the minimum value is -3.06mm. After reinforcement, the absolute value of the maximum vertical displacement is reduced by 58.1%.

[0077] like Figure 13 As shown, Path 1 is randomly selected in the X-axis direction at the maximum negative vertical displacement. Comparing the vertical displacement of Path 1 with that of the unreinforced path, the absolute value of the maximum vertical displacement is reduced after reinforcement on Path 1, indicating a significant reinforcement effect, and the maximum vertical displacement can be reduced by 4.25 mm.

[0078] The vertical displacement of the frame column is calculated. After reinforcement, the maximum vertical displacement of the top of the frame column is 0.34mm and the minimum is -1.67mm.

[0079] Calculating the crack width of the roof, the maximum crack width of the roof was reduced to 0.304mm, but it was still greater than the specified limit of 0.02mm.

[0080] Calculating the top plate stress, the maximum stress value of the top beam has dropped from 64.664MPa when not reinforced to 14.844MPa, which is less than the standard value of the uniaxial compressive strength of C40 concrete, which is 26.8MPa.

[0081] S3. Fire escape selection

[0082] like Figure 14 As shown, a large fire truck passage needs to be reserved near the construction site of the square. The selection of the fire passage needs to ensure the safety of the hoisting construction and be close to the hoisting port to facilitate timely rescue without affecting the hoisting construction.

[0083] S4. Position selection

[0084] The station location includes the selection of the location of the lifting vehicle and the transport vehicle and the selection of the transport route, such as Figure 14 As shown, when hoisting on the left side, the transport vehicle stops on the northwest side of the left hoisting port and transports from the place where the vertical displacement of the west top plate is smaller and the place where the vertical displacement of the south top plate is smaller.

[0085] S5. Pedestrian and vehicle route selection

[0086] like Figure 15 As shown, pedestrian and vehicle access routes are located north of the transport vehicle station. Pedestrians and vehicles must be separated from transport and firefighting vehicles within the site. Pedestrians and vehicles should be located in areas of the remaining space that are convenient for entry and exit and minimize stress and strain. Traffic diversion controls should be implemented to prevent mixing with transport and firefighting vehicles.

[0087] S6. Hoisting

[0088] After the shield machine is split and disassembled, the crane lifts the components of the shield machine one by one onto the transport vehicle for loading and transportation.

[0089] Example 2

[0090] S1, preset lifting hole

[0091] Same as Example 1.

[0092] S2. Ground reinforcement analysis

[0093] Based on Example 1, Working Condition 3: Hoisting on the right side without reinforcement

[0094] 1. Calculate the vertical displacement of the top plate and beam, such as Figure 16 As shown in the figure, when the right opening was hoisted, the maximum vertical displacement and deflection of the top plate was 0.57mm, and the minimum was -7.22mm.

[0095] Depend on Figure 16 Analysis shows that the vertical displacement and deflection of the top plate and beam are in the range of -7.22mm to 0.57mm. The deflection exceeded the limit of 7mm during left and right side hoisting. When the vertical displacement of the top plate and beam approaches or exceeds the limit, reinforcement treatment is carried out.

[0096] Calculate the vertical displacement of the frame column. To facilitate the analysis, the frame column is set as follows: Figure 6 As shown, each row is numbered from left to right.

[0097] Calculate the vertical displacement of the frame column, such as Figure 17 As shown in the figure, when the right opening is hoisted, the maximum vertical displacement of the top of the frame column is 0.487mm, and the minimum is -2.286mm. The vertical displacement and deflection of the top plate and the beam are in the range of -2.28 to 0.048mm, and the vertical displacement of the top of 4% of the columns is above 1mm. When the maximum vertical displacement approaches or exceeds the limit, reinforcement treatment is carried out.

[0098] Table 2 Vertical displacement of the top of each column on the right side (unit: mm)

[0099]

[0100] 4. Calculate the width of the roof crack

[0101] The width of the crack on the top plate is as follows: Figure 18 As shown, the maximum crack width during the right hoisting occurs at unit 260301, which is located at Figure 18 The maximum crack width is 0.341 mm, which is marked with dots and exceeds the crack limit of 0.2 mm specified in the design of the structure.

[0102] 5. Calculate the stress of the top beam

[0103] When hoisting on the left side, the stress cloud diagram of the top beam is as follows Figure 19 As shown in the displacement cloud diagram, the stress values ​​of the top beam ranged from 0.026 to 38.1846 MPa during the right-hand hoisting operation. The concrete grade used in the top beam is C40, and the standard uniaxial compressive strength of C40 concrete is 26.8 MPa. During both left and right hoisting operations, the maximum stress values ​​of the top beam exceeded this value. When the maximum stress value of the top beam approaches or exceeds the limit, reinforcement is performed.

[0104] 4. Reinforcement

[0105] Based on Example 1, working condition 4: hoisting on the right side after reinforcement;

[0106] Calculations of the vertical displacement of the roof and beams revealed that after reinforcement, during hoisting at the right opening, the maximum vertical displacement of the roof was 0.042 mm, and the minimum was -3.06 mm. The absolute value of the maximum vertical displacement decreased by 57.6% after reinforcement, demonstrating significant reinforcement effectiveness.

[0107] like Figure 20As shown in the figure, path 2 is randomly selected in the X-axis direction at the maximum negative vertical displacement. Comparing the vertical displacement of path 2 with that of the unreinforced path, the absolute value of the maximum vertical displacement is reduced after reinforcement, indicating a significant reinforcement effect, and the maximum vertical displacement can be reduced by 4.16 mm.

[0108] The vertical displacement of the frame column was calculated. After reinforcement, the maximum vertical displacement at the top of the frame column was 0.35 mm, and the minimum was -1.17 mm. The maximum vertical displacement after reinforcement was less than the limit.

[0109] The crack width of the top plate was calculated. After reinforcement with disc-type scaffolding, the maximum crack width of the top plate was reduced to 0.135mm.

[0110] Calculating the top plate stress shows that the maximum stress in the top beam has dropped from 38.184 MPa without reinforcement to 14.048 MPa, which is less than the standard uniaxial compressive strength of C40 concrete, 26.8 MPa. This shows that using a disc-type scaffold can effectively reduce top beam stress.

[0111] S3. Fire escape selection

[0112] Same as Example 1.

[0113] S4. Position selection

[0114] The station location includes the selection of the location of the lifting vehicle and the transport vehicle and the selection of the transport route, such as Figure 21 As shown, when hoisting on the right side, the transport vehicle stops on the north side of the left hoisting port and transports from the west side top plate where the vertical displacement is smaller and the south side top plate where the vertical displacement is smaller.

[0115] S5. Pedestrian and vehicle route selection

[0116] like Figure 15 As shown, pedestrian and vehicle access routes are located north of the transport vehicle station. Pedestrians and vehicles must be separated from transport and firefighting vehicles within the site. Pedestrians and vehicles should be located in areas of the remaining space that are convenient for entry and exit and minimize stress and strain. Traffic diversion controls should be implemented to prevent mixing with transport and firefighting vehicles.

[0117] S6. Hoisting

[0118] After the shield machine is split and disassembled, the crane lifts the components of the shield machine one by one onto the transport vehicle for loading and transportation.

[0119] Example 3

[0120] Based on Example 1, the west side of the left tunnel opening can be reinforced, the lifting vehicle is located at the reinforced position on the west side of the left tunnel opening, and the loading vehicle is set on the south side of the left tunnel opening to shorten the transportation path.

[0121] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these 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 any one or more embodiments or examples.

[0122] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A method for hoisting a shield machine above an existing underground structure, characterized in that: The method comprises the following steps: S1, preset lifting hole; S2. Analyze and confirm whether reinforcement is necessary; Before reinforcement, numerical simulation modeling was used to compare the numerical changes of the existing structure with its bearing limits from three aspects: the vertical displacement of the top plate and beams, the vertical displacement of the frame columns, and the stress of the top beams, to determine whether reinforcement was necessary. S3, fire escape selection; S4. Selection of positions for lifting vehicles and transport vehicles; S5. Route selection for pedestrians and other vehicles; S6, hoisting construction; Said S1 includes reserving a hoisting hole on the original structure and laying a pre-installed cover plate on the hoisting hole; Said S4 includes setting up stations for transport vehicles and lifting vehicles near the lifting port, separated from the fire passage, pedestrian and other vehicle routes, the lifting vehicle is set at the reinforced ground, the bottom of the lifting vehicle is provided with a steel plate, and the transport route of the transport vehicle is selected at a position where the vertical displacement between the top plate and the beam is small; Said S6 comprises: after the shield machine is split, the hoisting vehicle sequentially hoists the components of the shield machine onto a transport vehicle for transportation; The reinforcement method of S2 is scaffolding reinforcement; The scaffolding comprises a vertical pole (4), both sides of which are connected to horizontal poles (5), a screw rod (2) is rotatably provided on the vertical pole (4), an adjusting nut (3) is fastened on the vertical pole (4), an adjustable support (1) is fastened on the top of the vertical pole (4), an I-beam for supporting the ground structure is connected to the adjustable support (1), and the I-beams on each vertical pole (4) are fastened to each other.

2. The method for hoisting a shield machine above an existing underground structure according to claim 1, characterized in that: The adjusting nut (3) cooperates with the screw rod (2).

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