Combined structure of large shield closed space passing starting base and counterforce frame and method

Abstract

The present application relates to a kind of large shield closed space passing starting base and counterforce frame combined structure and method, the arc-shaped steel structure base of the structure is respectively provided with concrete column in both sides, upper concrete large beam is fixedly connected in the top of concrete column, concrete diagonal brace is arranged between concrete column and upper concrete large beam, concrete thin-walled trapezoidal shear wall is arranged in the back side of concrete column, shield body is translated by placing in the tunnel lower segment of arc-shaped steel base and force transmission cooperation shield jacking jack jacking and passing station;Shield lower interval starts, and frame is formed by concrete column, upper concrete large beam and concrete diagonal brace, and combined with the concrete thin-walled trapezoidal shear wall behind concrete column, counterforce frame can provide enough shear bearing capacity to resist shield starting counterforce.The starting base and counterforce frame combined structure are used to solve the problems of large shield translation passing station, large-tonnage starting counterforce support and deformation control under the limited environment of closed space.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shield tunnel construction, and is suitable for shield launching construction, in particular to a large shield closed space passing station launching base and counterforce frame combined structure and method. BACKGROUND

[0002] Shield method construction is the most important construction method of tunnel construction at present, and is widely used in underground tunnel engineering field due to high safety and small influence on the surrounding environment.

[0003] When the shield launches and excavates, a component for providing a counterforce for the shield machine, i.e. a counterforce frame, needs to be installed, so as to provide a counterforce for the excavation of the shield machine in the process of advancing the shield machine. Generally, for conventional subway tunnels, the tunnel diameter is generally Φ6760~Φ7200, and the launching counterforce is generally about 2000T~4000T. The launching counterforce of a large-diameter shield (diameter > 12m) is greatly increased due to the increase of the self-weight of the shield body and the contact area between the shield shell and the soil. According to the experience of related engineering examples, the launching counterforce of a large shield reaches the level of 5000T~10000T, which brings great challenges to the strength and rigidity of the counterforce frame structure behind it.

[0004] On the other hand, for multiple large-diameter shield section construction, the high equipment cost of large shield and the progress of site construction period are comprehensively considered. After the excavation of the previous shield section and the completion of the intermediate working well, the whole shield machine is usually used for passing station in a closed space, and the next section is excavated and constructed. In order to facilitate the advancement of the large shield passing station working condition, the bottom plate elevation of the passing station area is usually smooth, and there is no structure obstruction in the left and right range. Therefore, it is not possible to set up a high-low step of the bottom plate and an L-shaped corner wall on the left and right sides as usual for the launching of the conventional working well to provide reliable permanent back counterforce seat support. There is also a major problem that cannot be solved by the setting of the large shield passing station launching counterforce frame, i.e. the lack of reliable existing permanent structure back support. SUMMARY

[0005] The purpose of the present application is to provide a closed space large shield passing station launching base and counterforce frame combined structure and method, which solves the problems of large shield translation passing station, large-tonnage launching counterforce support and deformation control in a limited closed space environment.

[0006] To achieve the above purpose, the following technical scheme is provided:

[0007] The application discloses a large-shield closed space passing starting base and counterforce frame combined structure, which comprises an arc-shaped steel structure base, concrete columns, an upper concrete large crossbeam, a concrete inclined brace and a concrete thin-wall trapezoidal shear wall at the back of the column, wherein the arc-shaped steel structure base is provided with concrete columns on both sides, the top of the concrete column is fixedly connected with the upper concrete large crossbeam, the concrete column and the upper concrete large crossbeam are provided with the concrete inclined brace, and the back of the concrete column is provided with the concrete thin-wall trapezoidal shear wall; the shield body is transmitted through the tunnel lower segment placed on the arc-shaped steel base and is pushed by the shield pushing jack to translate and pass through the station; the shield lower interval starting is formed by the left and right concrete columns, the upper concrete large crossbeam and the concrete inclined brace and is combined with the concrete thin-wall trapezoidal shear wall behind the left and right concrete columns to form the counterforce frame capable of providing sufficient shear bearing capacity to resist the shield starting counterforce.

[0008] Further, the arc-shaped steel structure base is formed by arc-shaped variable cross-section height variation and variable height arc-shaped H-shaped steel, rectangular notch inspection grooves are arranged on both sides of the arc-shaped steel structure base, longitudinal and transverse stiffening steel ribs are arranged in the web area in combination with the positions of three supporting points under the shield track beam; the longitudinal center distance between the arc-shaped steel structure bases is 1.07-1.86 m, five longitudinal steel pipes are adopted in the longitudinal direction and are connected by flange connection bolt holes and flange bolts; and three longitudinal track beams are connected through the lower part of the shield.

[0009] Further, the control height-width ratio of the concrete column is 2.5-3.0 to ensure the column stiffness, the inner edge line of the concrete column portal is controlled to be 70-120 mm from the building boundary of the subsequent shield trolley, and the column main reinforcement of the concrete column is connected with the upper middle plate and the lower bottom plate in a reserved bar insertion or bar embedding mode.

[0010] Further, the reserved bar insertion on the concrete column is provided with a column local corbel to ensure the support of the steel negative ring rear seat.

[0011] Further, the elevation of the concrete thin-wall trapezoidal shear wall is arranged in a right-angle trapezoidal mode, the bottom is connected with the bottom plate in a reserved bar insertion or bar embedding mode, and the contact surface is chiseled to ensure the shear bearing capacity of the shear wall rear seat; the rear side section and the top of the concrete thin-wall trapezoidal shear wall are closed by a T-shaped constraint member and a top pressing plate, the flange width b of the T-shaped constraint member is not greater than the width of the concrete column, and meanwhile, the plane position is controlled to be 70-120 mm from the building boundary of the subsequent shield trolley.

[0012] Further, the top pressing plate length of the concrete thin-wall trapezoidal shear wall is controlled to be customized to be close to the lower inverted beam of the middle plate, and the total length of the shear wall bottom is determined in combination with the maximum counterforce of shield starting.

[0013] Further, the upper concrete large beam controls the height-width ratio of 2.5-3.0 to ensure the rigidity of the upper beam, the elevation of the upper concrete large beam is controlled to be 70-120 mm away from the upper building boundary of the subsequent shield trolley, and the contact area with the negative ring is ensured as much as possible, and the main reinforcement of the upper concrete large beam is effectively anchored in the two side concrete columns.

[0014] Further, the concrete diagonal brace controls the height-width ratio of 2.5-3.0 to ensure the rigidity of the diagonal brace, the position of the concrete diagonal brace is set in combination with the position of the steel negative ring, and the contact area with the negative ring is ensured as much as possible, and the lower edge of the concrete diagonal brace is controlled to be 70-120 mm away from the building boundary of the subsequent shield trolley, and the main reinforcement of the concrete diagonal brace is effectively anchored in the column and the upper concrete large beam.

[0015] An implementation method of a large shield closed space passing station starting base combined with a reaction frame structure, the steps of which are:

[0016] S1: preliminary size determination of the large shield passing station starting reaction frame combined structure:

[0017] A three-dimensional force analysis model of the reaction frame is established, the column, beam and diagonal brace frame are adopted as beam elements, and the rear thin-walled shear wall is adopted as a plate element; in combination with the shield starting reaction oil cylinder and the effective contact of the steel negative ring and the reaction frame beam, the shield reaction force is distributed as a line load acting on the reaction frame beam, the bottom of the reaction frame is adopted as a fixed constraint, the operation calculation is carried out, and the total maximum deformation of the reaction frame is controlled to be within 15 mm;

[0018] According to the bending moment M , shear force V and torque T in the column, beam and diagonal brace frame beam, the component preliminary size and reinforcement are carried out; in combination with the maximum total shear force at the bottom of the reaction frame, the most unfavorable diagonal shortest shear surface is calculated to determine the shortest total length h 0 of the bottom of the shear wall of the reaction frame and the minimum height h of the end of the shear wall; 01 and the shear wall reinforcement;

[0019]

[0020]

[0021] In the formula: - the shear span ratio of the shear wall , - the design value of the tensile strength of concrete ， - the thickness of the shear wall, - the effective height of the horizontal length direction connection between the bottom of the shear wall and the bottom plate, - vertical height of the shear wall edge constraint member, - design value of tensile strength of the shear wall reinforcement, - cross-sectional area of the shear wall horizontal reinforcement, - spacing of the shear wall horizontal reinforcement; - diagonal section crack angle;

[0022] S2: shield station passing axis and subsequent trolley building boundary plane position line positioning;

[0023] S3: shield station passing steel structure base installation and fixation;

[0024] S4: after the front interval is received in position, the shield machine body is separated from the trolley, the shield machine body is translated and pushed forward on the steel structure base using the lower jack oil cylinder, and the lower segment is installed while being pushed forward, so as to provide lower counterforce support;

[0025] S5: the tail of the shield machine body is translated and pushed forward to the -6 steel negative ring of the shield starting of the next interval, the construction of the concrete counterforce frame is started, and the top surface of the counterforce frame is controlled to be in subsequent contact with the -8 steel negative ring;

[0026] S6: concrete shield counterforce frame construction, subsequent trolley building boundary is carried out according to the center elevation of the shield tunnel, the inner edge of the counterforce frame column, diagonal brace and upper cross beam is controlled to be positioned at 70~120mm of the trolley boundary, and curing is carried out for 28 days after concrete pouring is completed;

[0027] S7: the upper remaining segments of the -8 steel negative ring, -7 steel negative ring and -6 steel negative ring are installed, and are reinforced and fixed;

[0028] S8: the portal is removed, and subsequent -5 steel negative ring~-1 steel negative ring~+10 steel ring shield starting excavation construction is carried out, until the shield machine completely exits the reinforced area.

[0029] The beneficial effects of the present application are:

[0030] The present application provides a large shield station passing starting base and counterforce frame combined structure and method for the harsh environmental conditions of large shield station passing starting counterforce in a closed space, and no reliable existing permanent structure rear support. Compared with the problems of large deformation of the conventional rod system diagonal brace type counterforce frame and insufficient shear resistance of the bottom node diagonal brace, the starting base and counterforce frame combined structure is used to solve the problems of large shield translation station passing and large tonnage starting counterforce support and deformation control in a closed space limited environment. The total maximum deformation of the large tonnage shield starting counterforce frame is controlled within 15mm under the starting counterforce of 10000 ton level starting counterforce. The closed space large shield station passing starting is guaranteed. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1Figure 1 is a schematic diagram of a starting longitudinal section of a shield passing station base and counterforce frame combined structure according to the present application;

[0032] Figure 2 Figure 2 is a lateral section view of the combined counterforce frame;

[0033] Figure 3 Figure 3 is a schematic diagram of a starting plane of a shield passing station base and counterforce frame combined structure according to the present application;

[0034] Figure 4 Figure 4 is a reinforcement elevation view of the counterforce frame main reinforcement and stirrup;

[0035] Figure 5 Figure 5 is a schematic diagram of a counterforce frame beam reinforcement section;

[0036] Figure 6 Figure 6 is a counterforce frame rear leaning shear wall reinforcement view;

[0037] Figure 7 is a schematic diagram of a 2-2 section view, and Figure 8 is a schematic diagram of a 3-3 section view;

[0038] Figure 7 Figure 9 is a steel base lateral section view;

[0039] Figure 8 Figure 10 is a steel base plane view;

[0040] Figure 9 Figure 11 is a steel base longitudinal steel pipe and connecting node view;

[0041] Figure 12 is a schematic diagram of a main view, and Figure 13 is a schematic diagram of a b-b section view;

[0042] Figure 10 Figure 14 is a steel base guide rail lower web reinforcement view;

[0043] Figure 15 is a schematic diagram of a main view, and Figure 16 is a schematic diagram of a b-b section view;

[0044] Figure 11 Figure 17 is a shield machine body translation and propulsion transit working condition view;

[0045] Figure 12 Figure 18 is a starting working condition view of a shield passing station base and counterforce frame combined structure according to the present application;

[0046] Figure 13 Figure 19 is a schematic diagram of a three-dimensional model loading stress analysis of a steel base counterforce frame combined structure according to the present application;

[0047] Figure 14 Figure 20 is a schematic diagram of a shear stress of an unfavorable inclined section of a counterforce frame rear leaning shear wall;

[0048] In the diagram: 1. Base plate; 1-1. Shield shell; 1-2. Shield jacking jack; 2. Lower segments; 3. Base plate; 4. Arc-shaped steel structure base; 4-1. Variable height arc-shaped H-beam; 4-2. Inspection slot; 4-3. Longitudinal steel pipe; 4-301. Flange connection bolt holes; 4-302. Reinforcing rib steel plate; 4-4. Guide rail; 4-5. Web plate reinforcing rib; 5. Concrete column; 5-1. Partial corbel of column; 5-2. Main reinforcement of column; 5-3. Stirrups of column; 6. 1. Concrete main beam, 6-1 main reinforcement of beam, 6-2 stirrups of beam, 7. Concrete diagonal brace, 7-1 main reinforcement of diagonal brace, 7-2 stirrups of diagonal brace, 8. Shear wall, 8-1 main reinforcement of shear wall, 8-2 tie bars of shear wall, 9. Edge restraint member, 9-1 main reinforcement of restraint member, 10. Top plate, 10-1 main reinforcement of top plate, 11. Steel negative ring, 12. Middle plate, 13. Middle plate under-turning beam, 14. Shield tunnel trolley construction boundary, 15. Segment already connected in the previous section. Detailed Implementation

[0049] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0050] like Figures 1-14 As shown, a combined structure of a large shield tunneling machine (TBM) launching base and reaction frame in a confined space includes an arc-shaped steel base 4, left and right concrete columns 5, an upper concrete horizontal beam 6, concrete diagonal braces 7, and a thin-walled trapezoidal shear wall 8 behind the columns. Left and right concrete columns 5 are located on both sides of the arc-shaped steel base 4. The upper concrete horizontal beam 6 is fixed to the top of each column 5. Concrete diagonal braces 7 are located between the columns 5 and the beam 6. The thin-walled trapezoidal shear wall 8 is located behind the columns 5. The shield body is moved across the station by transmitting force through the lower tunnel segments 2 placed on the arc-shaped steel base 4, combined with the pushing action of the TBM jacks 1-2. When the TBM launches into the next section, a frame is formed by the concrete columns 5, the upper concrete horizontal beam 6, and the concrete diagonal braces 7, which, together with the thin-walled trapezoidal shear wall 8 behind the columns 5, forms a reaction frame providing sufficient shear resistance to resist the TBM launching reaction force.

[0051] Arc-shaped steel structure base 4, gradually changes from H2000x500x20x30 to H900x500x20x30 (wing plate width 500 mm, thickness 30 mm, web thickness 20 mm) arc-shaped variable cross-section height changes, forms variable height arc-shaped H-shaped steel 4-1, each side is provided with a rectangular notch maintenance groove 4-2, and three longitudinal 100x100 mm track beams are connected through below the shield support. The arc-shaped steel structure base 4 is provided with longitudinal and transverse stiffening steel ribs 4-302 in the web area in combination with the positions of the three support points of the shield track beam below, and the stiffening rib steel plate 4-302 has a thickness of 20 mm. The longitudinal center distance between the arc-shaped steel structure bases 4 is 1.07-1.86 m. Five longitudinal steel pipes 4-3 with a diameter of 529x10 are used in the longitudinal direction, and are connected by flange connection bolt holes 4-301 using flange bolts.

[0052] The concrete column 5 of the counterforce frame is made of C35-C40 concrete material, has a section of 1000-1200 mm and a height of 2500-3500 mm (the height direction is parallel to the center line direction of the shield), the height-width ratio is controlled to be 2.5-3.0 to ensure the rigidity of the column, the inner edge line of the column portal is controlled to be 70-120 mm away from the building boundary of the subsequent trolley of the shield, and the contact area with the negative ring is ensured as much as possible. The main reinforcement 5-2 of the column can be connected to the upper middle plate and the lower bottom plate by using the reserved reinforcing bar or the embedded reinforcing bar at the top and the bottom of the column. Further, the gap between the lower segment 2 and the concrete column 5 is provided with a local column bracket 5-1 by reserving the reinforcing bar on the concrete column 5 to ensure the support of the rear seat of the steel negative ring.

[0053] The rear side thin-walled shear wall 8 of the counterforce frame column is made of C35-C40 concrete material, has a thickness of 250-400 mm, and the vertical face of the shear wall 8 is arranged in a right-angle trapezoidal shape. The bottom is connected to the bottom plate by using the reserved reinforcing bar or the embedded reinforcing bar, and the contact surface is chiseled to ensure the shear resistance of the rear seat of the shear wall. The rear side section of the shear wall is closed by using a T-shaped constraint member and a top pressing plate, the flange width b of the T-shaped constraint member is not greater than the width of the column, the thickness is controlled to be 400-600 mm, and the plane position is ensured to be 70-120 mm away from the building boundary of the subsequent trolley of the shield. The length of the top pressing plate of the shear wall is controlled to be the length of the custom-made lower turning beam 13 of the adjacent middle plate, and the total length of the bottom of the shear wall is determined in combination with the calculation of the maximum counterforce of the shield starting.

[0054] The upper concrete large beam 6 of the counterforce frame adopts C35-C40 concrete material, has a cross-sectional width of 1200-1500 mm, a height of 3000-3500 mm (the height direction is parallel to the center line direction of the shield), and a height-width ratio of 2.5-3.0 to ensure the rigidity of the upper beam, and the elevation of the upper concrete large beam 6 is controlled to be 70-120 mm away from the upper building boundary of the subsequent shield trolley, and the contact area with the negative ring is ensured as much as possible. The beam main reinforcement 6-1 of the upper concrete large beam 6 is effectively anchored in the two side columns.

[0055] The concrete inclined strut 7 of the counterforce frame adopts C35-C40 concrete material, has a cross-sectional width of 1000-1200 mm, a height of 2500-3000 mm (the height direction is parallel to the center line direction of the shield), and a height-width ratio of 2.5-3.0 to ensure the rigidity of the inclined strut, and the position of the concrete inclined strut 7 is set in combination with the position of the steel negative ring, and the contact area with the negative ring is ensured as much as possible, and the distance between the lower edge of the concrete inclined strut 7 and the building boundary 14 of the subsequent shield trolley is controlled to be 70-120 mm. The inclined strut main reinforcement 7-1 is effectively anchored in the column and the upper concrete large beam 6.

[0056] An implementation method of a closed space large shield passing station starting base and counterforce frame combined structure, the steps of which are:

[0057] S1: preliminary size determination of the large shield passing station starting counterforce frame combined structure:

[0058] A three-dimensional stress analysis model of the counterforce frame is established, the column, beam and inclined strut frame are adopted as beam elements, and the rear thin-walled shear wall is adopted as a plate element. In combination with the effective contact of the shield starting counterforce cylinder and the steel negative ring with the frame beam of the counterforce frame, the shield counterforce is distributed as a line load acting on the frame beam of the counterforce frame, the bottom of the counterforce frame is adopted as a fixed constraint, and the operation calculation is performed, and the total maximum deformation of the counterforce frame is controlled to be within 15 mm.

[0059] The member preliminary size and reinforcement are determined according to the internal force (bending moment M , shear force V and torque T ) of the column, beam and inclined strut frame beam.

[0060] The maximum total shear force at the bottom of the counterforce frame is determined in combination with the total horizontal counterforce at the bottom of the counterforce frame, and the shear calculation is performed on the most unfavorable inclined shortest shear surface, so as to determine the shortest total length h 0 of the shear wall at the bottom of the counterforce frame, and the minimum height h 01 of the end of the shear wall.

[0061]

[0062]

[0063] In the formula: - shear wall shear span ratio , - design value of concrete tensile strength ， - shear wall thickness, - effective height of horizontal length direction connection between shear wall bottom and floor, - vertical height of shear wall edge restraint member, - design value of shear wall steel tensile strength, - shear wall horizontal steel sectional area, - shear wall horizontal steel spacing; - diagonal section fracture angle.

[0064] S2: Positioning of the shield passing through the station axis and the subsequent trolley building boundary plane position.

[0065] S3: Installation and fixation of the shield passing through the station steel structure base.

[0066] S4: After the front interval is received in place, the shield body is separated from the trolley, and the shield body is translated and advanced on the steel structure base using the lower jack cylinder, and the lower segment is installed while advancing, to provide lower counterforce support.

[0067] S5: The tail of the shield body is translated and advanced to the -6 steel negative ring of the shield starting point of the next interval, and the construction of the concrete counterforce frame is started, and the top surface of the counterforce frame is controlled to be in contact with the -8 steel negative ring.

[0068] S6: Construction of the concrete shield counterforce frame, with the subsequent trolley building boundary being the center elevation of the shield tunnel, and the counterforce frame column, diagonal brace and upper beam inner edge are positioned 70-120mm from the trolley boundary. After the concrete is poured, it is cured for 28 days.

[0069] S7: Installation of the -8 steel negative ring, -7 steel negative ring and the upper remaining segments of the -6 steel negative ring, and reinforcement and fixation.

[0070] S8: Hole portal is removed, and subsequent -5~ -1~+10 ring shield starting excavation construction is carried out until the shield machine completely exits the reinforced area.

Claims

1. A method for implementing a combined structure of a large shield tunneling machine's enclosed space station launching base and reaction frame, comprising an arc-shaped steel structure base, concrete columns, an upper concrete horizontal beam, concrete diagonal braces, and a thin-walled trapezoidal shear wall of concrete behind the columns. Concrete columns are respectively provided on both sides of the arc-shaped steel structure base. The upper concrete horizontal beam is fixedly connected to the top of each concrete column. Concrete diagonal braces are provided between the concrete columns and the upper concrete horizontal beam. A thin-walled trapezoidal shear wall of concrete is provided behind the concrete columns. The shield body is moved across the station by transmitting force through the lower tunnel segments placed on the arc-shaped steel base and by being pushed by shield tunneling jacks. The shield machine launches into the next section, forming a frame through the left and right concrete columns, the upper concrete horizontal beam, and the concrete diagonal braces, combined with the thin-walled trapezoidal shear wall behind the left and right concrete columns to form a reaction frame that provides sufficient shear bearing capacity to resist the shield machine's launching reaction force. Its features are, The implementation method involves the following steps: S1: Preliminary dimensions of the combined reaction frame structure for the large shield tunneling machine's starting station have been determined. Establish a three-dimensional stress analysis model of the reaction frame. The concrete columns, upper concrete main beams and concrete diagonal bracing frames adopt beam elements, and the concrete thin-walled trapezoidal shear wall at the rear adopts plate elements; considering the effective contact between the shield starting reaction cylinders and the steel negative ring and the frame beams of the reaction frame, the shield reaction force is correspondingly distributed and applied to the frame beams of the reaction frame as a line load. The bottom of the reaction frame is subjected to fixed constraints, and the operation calculation is carried out to control the overall maximum deformation of the reaction frame within 15 mm; according to the bending moment M , shear force V and torque T in the concrete columns, upper concrete main beams and concrete diagonal bracing frame beams, the preliminary dimensions and reinforcement of the components are carried out; The maximum total shear force at the bottom of the reaction frame is determined by combining the total horizontal reaction force at the bottom of the reaction frame. Shear resistance is then checked using the shortest shear plane along the most unfavorable diagonal direction, thereby determining the shortest total length at the bottom of the reaction frame shear wall. h 0, and the minimum height at the end of the shear wall h 01 and reinforcement of shear walls; In the formula: -Shear wall shear span ratio , -Design value of concrete tensile strength ， -Shear wall thickness -Effective height of the horizontal length connection between the shear wall base and the base slab. - Vertical height of shear wall edge restraint members -Design value of tensile strength of shear wall reinforcement - Cross-sectional area of ​​horizontal reinforcement in shear wall - Spacing of horizontal reinforcement bars in shear walls; -Angle of fracture at inclined section; S2: Laying out and positioning the shield tunnel's transit axis and the subsequent trolley building boundary in plan view; S3: Installation and fixing of steel structure base for shield tunneling station; S4: After the previous section is received, the shield machine body separates from the trolley. The shield machine body is moved and advanced on the arc-shaped steel structure base by the lower jack cylinder. The lower segments are installed while advancing to provide lower reaction support. S5: The tail of the tunnel boring machine moves horizontally to the -6 steel negative ring where the next section of the tunnel boring machine starts, and begins the construction of the concrete reaction frame, controlling the top surface of the reaction frame to make subsequent contact with the -8 steel negative ring; S6: Concrete shield reaction frame construction, the subsequent trolley construction boundary is determined by the center elevation of the shield tunnel, and the inner edge of the concrete column, concrete brace and upper concrete beam of the reaction frame is positioned 70~120mm away from the trolley boundary. After the concrete is poured, it is cured for 28 days. S7: Install the remaining segments above the -8 steel negative ring, -7 steel negative ring, and -6 steel negative ring, and reinforce and fix them; S8: The tunnel portal is removed, and subsequent shield tunneling construction begins with the -5 steel negative ring ~ -1 steel negative ring ~ +10 steel ring, until the shield machine completely exits the reinforced area.

2. The implementation method of the combined structure of the large shield tunneling machine's enclosed space station starting base and reaction frame according to claim 1, characterized in that: The arc-shaped steel structure base is formed by arc-shaped variable cross-section height change and variable height arc-shaped H-beams. Rectangular recessed maintenance grooves are set on both sides. The arc-shaped steel structure base is equipped with longitudinal and transverse stiffening steel ribs in the web area in conjunction with the three support points under the shield tunnel track beam. The longitudinal center spacing between the arc-shaped steel structure bases is 1.07~1.86m. Five longitudinal steel pipes are used in the longitudinal direction and connected by flange bolts through flange connection bolt holes. Three longitudinal track beams are connected and connected through the shield tunnel to transmit force below.

3. The implementation method of the combined structure of the large shield tunneling machine's enclosed space station starting base and reaction frame according to claim 1, characterized in that: The height-to-width ratio of the concrete column is controlled at 2.5 to 3.0 to ensure the column's rigidity. The inner edge of the concrete column gantry is controlled to be 70mm to 120mm from the boundary of the shield tunneling trolley. The main reinforcement bars of the concrete column are connected to the upper middle plate and the lower bottom plate by pre-reserved dowel bars or anchor bars at the top and bottom of the column.

4. The implementation method of the combined structure of the large shield tunneling machine's enclosed space station starting base and reaction frame according to claim 3, characterized in that: The concrete column has pre-reserved reinforcing bars to form a partial corbel, ensuring the support of the steel negative ring rear seat.

5. The implementation method of the combined structure of the large shield tunneling machine's enclosed space station starting base and reaction frame according to claim 1, characterized in that: The facade of the concrete thin-walled trapezoidal shear wall is arranged in a right-angled trapezoidal shape. The bottom is connected to the base plate by pre-reserved dowel bars or anchor bars, and the contact surface is roughened to ensure the shear bearing capacity of the rear seat of the shear wall. The rear section and top of the concrete thin-walled trapezoidal shear wall are closed by T-shaped restraint members and capping plates. The flange width b of the T-shaped restraint members is not greater than the width of the concrete column, while ensuring that the plane position is 70mm~120mm away from the boundary of the shield tunneling trolley.

6. The implementation method of the combined structure of the large shield tunneling machine's enclosed space station starting base and reaction frame according to claim 5, characterized in that: The length of the top capping plate of the concrete thin-walled trapezoidal shear wall is controlled by customizing the adjacent middle plate under-turning beam. The total length of the bottom of the concrete thin-walled trapezoidal shear wall is determined by combining the calculation of the maximum reaction force at the start of the shield tunnel.

7. The implementation method of the combined structure of the large shield tunneling machine's enclosed space station starting base and reaction frame according to claim 1, characterized in that: The upper concrete main beam is controlled with a height-to-width ratio of 2.5 to 3.0 to ensure its rigidity. The elevation of the upper concrete main beam is controlled such that the lower edge of the beam is 70mm to 120mm away from the upper building boundary of the shield tunneling trolley, and the contact area with the negative ring is maximized. The main reinforcement of the upper concrete main beam is effectively anchored in the concrete columns on both sides.

8. The implementation method of the combined structure of the large shield tunneling machine's enclosed space station starting base and reaction frame according to claim 1, characterized in that: The concrete diagonal bracing is controlled with a height-to-width ratio of 2.5 to 3.0 to ensure its rigidity. The position of the concrete diagonal bracing is set in conjunction with the position of the steel negative ring, and the contact area with the negative ring is maximized. The lower edge of the concrete diagonal bracing is controlled to be 70mm to 120mm away from the boundary of the shield tunneling trolley. The main reinforcement of the concrete diagonal bracing is effectively anchored in the column and the upper concrete beam.

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