A design method for stacked shield tunnels in long-distance adjacent operating subway tunnels

Abstract

The present invention discloses a design method for a stacked shield tunnel that is close to an operating subway tunnel over a long distance, including the following steps: conducting a current status survey, measurement, and data collection of an operating subway tunnel; providing a residual deformation margin control value for the operating subway tunnel through numerical three-dimensional inversion calculation, and verifying a tunnel structure bearing capacity margin control value; determining the net distance between the upper and lower holes of the newly built stacked tunnel; determining the plane net distance between the newly built stacked tunnel and the existing operating subway tunnel; determining the vertical net distance between the newly built stacked tunnel and the existing operating subway tunnel; and determining a reinforcement plan for the stacked shield tunnel. Aiming at the complexity of the stacked shield tunnel being close to an operating subway tunnel over a long distance, the present invention provides a method for determining the critical value of the mutual distance relationship between the two, and provides a reinforcement plan based on the critical value, which greatly simplifies the complexity of the problem, facilitates operation, and can be used as a reference in similar complex projects.

Description

Technical Field

[0001] The invention belongs to the field of subway tunnel engineering, and in particular relates to a stacked-line shield design method for a long-distance adjacent operating subway tunnel. Background Art

[0002] Since the 21st century, domestic subway projects have developed rapidly, and major key areas have basically had operating subways. As the network continues to be intensified, under the conditions of narrow roads in the old urban areas, the construction of multiple subway tunnels is an inevitable practical problem. The long-distance proximity of newly built overlapping tunnels to operating subway tunnels can overcome the difficulties of narrow space in the old urban areas and become a solution for cities to choose to build subways. There are already many cases in China for reference for overlapping tunnels. The long-distance proximity of newly built overlapping tunnels to operating subway tunnels must not only overcome the difficulties in tunnel construction itself, but also ensure the safety of operating lines and the personal safety of the public. This is a major technical problem to be solved in the engineering field. This complex project will bring great instability and various practical problems to the implementation of the project, and even worse, lead to operational safety accidents. Therefore, it is urgent and necessary to solve such practical difficulties. Summary of the invention

[0003] The present invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a stacked shield design method for a long-distance adjacent operating subway tunnel.

[0004] The technical solution of the present invention is: a design method of a stacked shield machine for a long-distance adjacent operating subway tunnel, comprising the following steps:

[0005] A. Conduct current status survey, measurement and data collection of operating subway tunnels;

[0006] B. Through numerical three-dimensional inversion calculation, the remaining deformation margin control value of the operating subway tunnel is given, and the bearing capacity margin control value of the tunnel structure is verified;

[0007] C. Determine the clear distance between the upper and lower tunnels of the newly built superimposed tunnel;

[0008] D. Determine the plane clearance between the newly built overlapping tunnel and the existing operating subway tunnel;

[0009] E. Determine the vertical clearance between the newly built overlapping tunnel and the existing operating subway tunnel;

[0010] F. Determine the reinforcement plan for the stacked shield tunnel.

[0011] Furthermore, step A conducts current status investigation, measurement and data collection of operating subway tunnels. The specific process is as follows:

[0012] First, investigate and collect archived construction drawings of operational subway tunnels;

[0013] Then, the deformation S of the operating subway tunnel was measured. 1 , deformed S 1 Including settlement deformation monitoring data, lateral deformation monitoring data, and radial convergence monitoring data.

[0014] Furthermore, step B uses numerical three-dimensional inversion calculation to give the remaining deformation margin control value of the operating subway tunnel and verify the tunnel structure bearing capacity margin control value. The specific process is as follows:

[0015] Firstly, based on the archived construction drawings of the operating subway tunnel, the design bearing capacity and allowable deformation of the operating tunnel were obtained;

[0016] Then, based on the archived construction drawings of the operating subway tunnel, the Midas three-dimensional numerical calculation model was established to calculate the internal forces of the operating tunnel structure;

[0017] Then, based on the design bearing capacity and the internal force of the operating tunnel structure, the control value of the tunnel structure bearing capacity margin is obtained;

[0018] Finally, the remaining deformation margin control value of the operating subway tunnel is obtained based on the allowable deformation of the operating tunnel and the deformation of the operating tunnel.

[0019] Furthermore, based on the archived construction drawings of the operating subway tunnel, the design bearing capacity and allowable deformation of the operating tunnel are obtained. The specific process is as follows:

[0020] First, check the segment type and reinforcement form of the operating tunnel according to the archived construction drawings of the operating subway tunnel;

[0021] Then, the design bearing capacity F is obtained, which includes bending moment, axial force and shear force;

[0022] Finally, the allowable operational tunnel deformation S is obtained.

[0023] Furthermore, the allowed deformation S of the operating tunnel includes settlement deformation of the subway tunnel, lateral deformation of the operating subway tunnel, and radial convergence of the operating subway tunnel.

[0024] Furthermore, based on the archived drawings of the construction of the operating subway tunnel, a Midas three-dimensional numerical calculation model was established to calculate the internal forces of the operating tunnel structure. The specific process is as follows:

[0025] Firstly, a MIDAS three-dimensional numerical calculation model was established based on the archived construction drawings of the operating subway tunnel;

[0026] Then, the transformed S 1 , namely, the settlement deformation monitoring data, lateral deformation monitoring data, and radial convergence monitoring data, which are applied to the operating subway tunnel as additional displacement deformation;

[0027] Finally, the internal force F of the operating tunnel structure is calculated. 1 .

[0028] Furthermore, the tunnel structure bearing capacity margin control value is F 0 =FF 1 The remaining deformation margin control value of the operating subway tunnel is S 0 =SS 1 .

[0029] Furthermore, step C determines the clearance between the upper and lower tunnels of the newly built superimposed tunnel. The specific process is as follows:

[0030] First, determine the construction sequence of the upper and lower tunnels of the new overlapping tunnel;

[0031] Then, determine the construction distance between the upper and lower tunnels of the newly built overlapping tunnel;

[0032] Finally, determine the net distance between the upper and lower holes of the newly built stacked tunnel.

[0033] Furthermore, step D determines the plane clearance between the newly built overlapping tunnel and the existing operating subway tunnel. The specific process is as follows:

[0034] First, it is assumed that the vertical clearance L between the upper tunnel of the newly built superimposed tunnel and the operating subway tunnel is 0;

[0035] Then, based on the Midas three-dimensional numerical calculation model in step B, a new stacked tunnel is added, and the plane distances of the new stacked tunnel are respectively multiple groups;

[0036] Then, after adding the newly built superimposed tunnel, the additional internal forces of the operating subway tunnel structure are extracted respectively;

[0037] After that, after adding the newly built overlapping tunnel, the deformation value of each operating tunnel is added;

[0038] Finally, the power function is used to simulate the curve function of the plane clearance D and the additional internal force of the operating subway tunnel structure and the additional deformation value of the operating tunnel. The plane clearance D at the inflection point of the curve is obtained by curve fitting. 0 .

[0039] Furthermore, step E determines the vertical clearance between the newly built superimposed tunnel and the existing operating subway tunnel. The specific process is as follows:

[0040] First, based on step D, we get the plane clearance D 0 ;

[0041] Then, establish multiple groups of vertical clearances between the upper tunnel of the newly built superimposed tunnel and the operating subway tunnel;

[0042] Then, according to the three-dimensional numerical calculation results, the additional internal forces of the operating subway tunnel structure are extracted respectively;

[0043] Then, according to the three-dimensional numerical calculation results, the additional deformation values ​​of the operating tunnels were extracted respectively;

[0044] Finally, the power function is used to simulate the curve function of the vertical clearance L and the additional internal force of the operating subway tunnel structure and the additional deformation value of the operating tunnel. The vertical clearance L is obtained by curve fitting. 0 Here, the additional internal force of the operating subway tunnel structure is greater than the control value of the tunnel structure bearing capacity margin, and the additional deformation value is greater than the control value of the remaining deformation margin of the operating subway tunnel.

[0045] The beneficial effects of the present invention are as follows:

[0046] Aiming at the complexity problem of stacked shield tunnels being close to operating subway tunnels at a long distance, the present invention provides a method for determining the critical value of the distance relationship between the two, and provides a reinforcement plan based on the critical value, which greatly simplifies the complexity of the problem and facilitates operation, and can be used as a reference in similar complex projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a flow chart of the method of the present invention;

[0048] Figure 2 The deformation S of the subway tunnel in operation is measured by the present invention. 1 , namely, settlement deformation monitoring data, lateral deformation monitoring data, and radial convergence monitoring data;

[0049] Figure 3 It is a numerical calculation model diagram in the present invention;

[0050] Figure 4 It is a curve function of the plane clearance D and the additional settlement deformation value of the operating subway tunnel in the present invention;

[0051] Figure 5 It is the curve function of the vertical clearance L and the additional settlement deformation value of the operating subway tunnel in the present invention;

[0052] Figure 6 It is a schematic diagram of grouting in a hole in the present invention;

[0053] Figure 7 It is a schematic diagram of isolation pile reinforcement in the present invention;

[0054] Figure 8 It is a schematic diagram of the full-section reinforcement of the surface in the present invention; DETAILED DESCRIPTION

[0055] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and embodiments:

[0056] like Figures 1 to 8 As shown, a design method for a stacked shield machine for a long-distance adjacent operating subway tunnel includes the following steps:

[0057] A. Conduct current status survey, measurement and data collection of operating subway tunnels;

[0058] B. Through numerical three-dimensional inversion calculation, the remaining deformation margin control value of the operating subway tunnel is given, and the bearing capacity margin control value of the tunnel structure is verified;

[0059] C. Determine the clear distance between the upper and lower tunnels of the newly built superimposed tunnel;

[0060] D. Determine the plane clearance between the newly built overlapping tunnel and the existing operating subway tunnel;

[0061] E. Determine the vertical clearance between the newly built overlapping tunnel and the existing operating subway tunnel;

[0062] F. Determine the reinforcement plan for the stacked shield tunnel.

[0063] Step A is to conduct current status investigation, measurement and data collection of operating subway tunnels. The specific process is as follows:

[0064] First, investigate and collect archived construction drawings of operational subway tunnels;

[0065] Then, the deformation S of the operating subway tunnel was measured. 1 , deformed S 1 Including settlement deformation monitoring data, lateral deformation monitoring data, and radial convergence monitoring data.

[0066] Furthermore, step B uses numerical three-dimensional inversion calculation to give the remaining deformation margin control value of the operating subway tunnel and verify the tunnel structure bearing capacity margin control value. The specific process is as follows:

[0067] Firstly, based on the archived construction drawings of the operating subway tunnel, the design bearing capacity and allowable deformation of the operating tunnel were obtained;

[0068] Then, based on the archived construction drawings of the operating subway tunnel, the Midas three-dimensional numerical calculation model was established to calculate the internal forces of the operating tunnel structure;

[0069] Then, based on the design bearing capacity and the internal force of the operating tunnel structure, the control value of the tunnel structure bearing capacity margin is obtained;

[0070] Finally, the remaining deformation margin control value of the operating subway tunnel is obtained based on the allowable deformation of the operating tunnel and the deformation of the operating tunnel.

[0071] Based on the archived construction drawings of the operating subway tunnel, the design bearing capacity and allowable deformation of the operating tunnel are obtained. The specific process is as follows:

[0072] First, check the segment type and reinforcement form of the operating tunnel according to the archived construction drawings of the operating subway tunnel;

[0073] Then, the design bearing capacity F is obtained, which includes bending moment, axial force and shear force;

[0074] Finally, the allowable operational tunnel deformation S is obtained.

[0075] The allowed deformation S of the operating tunnel includes settlement deformation of the subway tunnel, lateral deformation of the operating subway tunnel, and radial convergence of the operating subway tunnel.

[0076] Based on the archived drawings of the construction of the operating subway tunnel, the Midas three-dimensional numerical calculation model was established to calculate the internal forces of the operating tunnel structure. The specific process is as follows:

[0077] Firstly, a MIDAS three-dimensional numerical calculation model was established based on the archived construction drawings of the operating subway tunnel;

[0078] Then, the transformed S 1 , that is, the settlement deformation monitoring data, lateral deformation monitoring data, and radial convergence monitoring data are applied to the operating subway tunnel as additional displacement deformation;

[0079] Finally, the internal force F of the operating tunnel structure is calculated. 1 .

[0080] The tunnel structure bearing capacity margin control value is F 0 =FF 1 The remaining deformation margin control value of the operating subway tunnel is S 0 =SS 1 .

[0081] Step C determines the clearance between the upper and lower tunnels of the newly built superimposed tunnel. The specific process is as follows:

[0082] First, determine the construction sequence of the upper and lower tunnels of the new overlapping tunnel;

[0083] Then, determine the construction distance between the upper and lower tunnels of the newly built overlapping tunnel;

[0084] Finally, determine the net distance between the upper and lower holes of the newly built stacked tunnel.

[0085] Step D determines the plane clearance between the newly built overlapping tunnel and the existing operating subway tunnel. The specific process is as follows:

[0086] First, it is assumed that the vertical clearance L between the upper tunnel of the newly built superimposed tunnel and the operating subway tunnel is 0;

[0087] Then, based on the Midas three-dimensional numerical calculation model in step B, a new stacked tunnel is added, and the plane distances of the new stacked tunnel are respectively multiple groups;

[0088] Then, after adding the newly built superimposed tunnel, the additional internal forces of the operating subway tunnel structure are extracted respectively;

[0089] After that, after adding the newly built overlapping tunnel, the deformation value of each operating tunnel is added;

[0090] Finally, the power function is used to simulate the curve function of the plane clearance D and the additional internal force of the operating subway tunnel structure and the additional deformation value of the operating tunnel. The plane clearance D at the inflection point of the curve is obtained by curve fitting. 0 .

[0091] Specifically, a new stacked tunnel is added to the calculation model, and nine three-dimensional numerical models with plane distances of 0.1dm, 0.2dm, 0.4dm, 0.6dm, 0.8dm, 1.0dm, 1.5dm, 2.0dm, and 3.0dm are established, where d is the diameter of the shield tunnel.

[0092] Specifically, the plane clearance D at the inflection point of the curve is obtained by curve fitting: 0 , as follows:

[0093] X=A 1 (D+B 1 ) C +D 1

[0094] Where X is the additional internal force and additional deformation of the operating subway tunnel structure; A 1 , B 1 , C, D 1 is the fitting coefficient.

[0095] Step E determines the vertical clearance between the newly built superimposed tunnel and the existing operating subway tunnel. The specific process is as follows:

[0096] First, based on step D, we get the plane clearance D 0 ;

[0097] Then, establish multiple groups of vertical clearances between the upper tunnel of the newly built superimposed tunnel and the operating subway tunnel;

[0098] Then, according to the three-dimensional numerical calculation results, the additional internal forces of the operating subway tunnel structure are extracted respectively;

[0099] Then, according to the three-dimensional numerical calculation results, the additional deformation values ​​of the operating tunnels were extracted respectively;

[0100] Finally, the power function is used to simulate the curve function of the vertical clearance L and the additional internal force of the operating subway tunnel structure and the additional deformation value of the operating tunnel. The vertical clearance L is obtained by curve fitting. 0 Here, the additional internal force of the operating subway tunnel structure is greater than the control value of the tunnel structure bearing capacity margin, and the additional deformation value is greater than the control value of the remaining deformation margin of the operating subway tunnel.

[0101] Specifically, nine three-dimensional numerical models were established with vertical clearances L of 0.1dm, 0.2dm, 0.4dm, 0.6dm, 0.8dm, 1.0dm, 1.5dm, 2.0dm and 3.0dm between the upper hole of the newly built superimposed tunnel and the operating subway tunnel, where d is the diameter of the shield tunnel.

[0102] Specifically, step F determines the reinforcement scheme for the stacked shield tunnel, and the specific process is as follows:

[0103] For D>D 0 Under these conditions, the stacked shield tunnel does not need to adopt a reinforcement solution, and the operating tunnel adopts a dynamic monitoring solution;

[0104] For D=D 0 , L ≥ L 0 Under these conditions, the stacked shield tunnel does not need to adopt a reinforcement solution, and the operating tunnel adopts a dynamic monitoring solution;

[0105] For D=D 0 , L<L 0 Under these conditions, the stacked shield tunnel adopts the in-tunnel grouting scheme, and the operating tunnel adopts the dynamic monitoring scheme;

[0106] For D < D 0 Under these conditions, the stacked shield tunnel adopts isolation piles and full-section grouting scheme, and the operating tunnel adopts a dynamic monitoring scheme. Example

[0107] A design method for a stacked shield machine for a long-distance adjacent operating subway tunnel, as shown in Figure 1, includes the following steps:

[0108] Step A. Conduct current status survey, measurement and data collection of operating subway tunnels;

[0109] The main tasks include investigating, measuring and collecting the construction archive drawings of the subway line 4 tunnel, the settlement and deformation monitoring data of the subway line 4 tunnel, the lateral deformation monitoring data of the subway line 4 tunnel, and the radial convergence monitoring data of the subway line 4 tunnel, such as Figure 2 As shown;

[0110] Step B. by numerical three-dimensional inversion calculation, the control value of the remaining deformation margin of the operating subway tunnel and the control value of the bearing capacity margin of the tunnel structure are given;

[0111] According to the archived construction drawings of the subway line 4 tunnel in operation, it was found that the segment type of the operating tunnel is 6.2m in outer diameter, the segment thickness is 0.35m, the reinforcement is Class 3, the design bearing capacity is F (bending moment is 250kN*m, axial force is 800kN and shear force is 380kN) and the allowable deformation of the subway line 4 tunnel in operation is S (subway tunnel settlement deformation is 20mm, operating subway tunnel lateral deformation is 10mm, and operating subway tunnel radial convergence is 10mm). According to the measurement results, the operating tunnel has deformed S 1 , that is, the settlement deformation monitoring data is 11mm, the lateral deformation monitoring data is 5.1mm, and the radial convergence monitoring data is 5.3mm;

[0112] The Midas three-dimensional numerical calculation model was established based on the archived construction drawings of the operating subway tunnel. The settlement deformation monitoring data, lateral deformation monitoring data, and radial convergence monitoring data of the operating subway tunnel were applied to the operating subway tunnel as additional displacement deformation to calculate the internal force F of the operating tunnel structure. 1 (bending moment is 180kN*m, axial force is 650kN and shear force is 280kN);

[0113] The tunnel structure bearing capacity margin control value is obtained as F 0 (bending moment is 70kN*m, axial force is 150kN and shear force is 100kN) = FF 1 ; Control value S of remaining deformation margin of operating subway tunnel 0 (settlement deformation 9mm, lateral deformation 4.9mm, radial convergence 4.7mm) = SS 1 ;

[0114] Step C. Determine the net distance between the upper and lower tunnels of the newly built overlapping tunnel;

[0115] The construction sequence of the present invention is to construct the lower hole first and then the upper hole. The construction distance between the two holes differs by 30m to 50m, and the net distance between the upper and lower holes is 0.5d to 1d, where d is the diameter of the shield tunnel.

[0116] Step D: Determine the plane clearance D between the newly built overlapping tunnel and the existing operating subway tunnel 0 ;

[0117] Based on the conditions determined in step C, it is assumed that the vertical clearance L between the upper hole of the newly built superimposed tunnel and the operating subway tunnel is 0. According to the calculation conditions of step B, the newly built superimposed tunnel is added to the calculation model, and 9 three-dimensional numerical models with plane distances of 0.1dm, 0.2dm, 0.4dm, 0.6dm, 0.8dm, 1.0dm, 1.5dm, 2.0dm, and 3.0dm (d is the diameter of the shield tunnel) are established;

[0118] According to the results of three-dimensional numerical calculation, the additional internal forces (bending moment, axial force, shear force) of the operating subway tunnel structure and the additional deformation values ​​(settlement deformation, lateral deformation, radial convergence value of the operating subway tunnel) of the operating tunnel are extracted respectively.

[0119] The power function is used to simulate the curve function of the plane clearance D and the additional internal force and additional deformation value of the operating subway tunnel structure. The plane clearance D at the inflection point of the curve is obtained by curve fitting. 0 is 0.8d, such as Figure 4 The curve function of plane clearance D and additional settlement deformation value of operating subway tunnel is shown as an example;

[0120] Step E. Determine the vertical clearance L between the new overlapping tunnel and the existing operating subway tunnel 0 ;

[0121] Under step D, the plane distance is D 0 , establish nine three-dimensional numerical models with vertical clearance L of 0.1dm, 0.2dm, 0.4dm, 0.6dm, 0.8dm, 1.0dm, 1.5dm, 2.0dm and 3.0dm (d is the diameter of the shield tunnel) between the upper hole of the newly built superimposed tunnel and the operating subway tunnel;

[0122] According to the results of three-dimensional numerical calculation, the additional internal forces (bending moment, axial force, shear force) of the operating subway tunnel structure and the additional deformation values ​​(settlement deformation, lateral deformation, radial convergence value of the operating subway tunnel) of the operating tunnel are extracted respectively.

[0123] The power function is used to simulate the curve functions of the vertical clearance L and the additional internal force and additional deformation of the operating subway tunnel structure. The vertical clearance L at the curve where the additional internal force and additional deformation of the operating subway tunnel structure are greater than the control value of the tunnel structure bearing capacity margin and the control value of the remaining deformation margin of the operating subway tunnel is obtained through curve fitting. 0 is 0.4d, such as Figure 5 The vertical clearance L and the additional settlement deformation value curve function of the operating subway tunnel are shown as an example;

[0124] Step F. Determine the reinforcement scheme for the stacked shield tunnel;

[0125] For D>D 0 Under these conditions, the stacked shield tunnel does not need to adopt a reinforcement solution, and the operating tunnel adopts a dynamic monitoring solution;

[0126] For D=D 0 , L ≥ L 0 Under these conditions, the stacked shield tunnel does not need to adopt a reinforcement solution, and the operating tunnel adopts a dynamic monitoring solution;

[0127] For D=D 0 , L<L 0Under these conditions, the stacked shield tunnel adopts the in-tunnel grouting scheme, such as Figure 6 As shown, a dynamic monitoring solution is adopted in the operating tunnel;

[0128] For D < D 0 Under these conditions, isolation piles are used in stacked shield tunnels, such as Figure 7 As shown in the figure, and the full-section grouting scheme, as Figure 8 As shown, a dynamic monitoring solution is adopted in the operating tunnel.

[0129] Aiming at the complexity problem of stacked shield tunnels being close to operating subway tunnels at a long distance, the present invention provides a method for determining the critical value of the distance relationship between the two, and provides a reinforcement plan based on the critical value, which greatly simplifies the complexity of the problem and facilitates operation, and can be used as a reference in similar complex projects.

Claims

1. A design method for a stacked shield machine for a long-distance adjacent operating subway tunnel, characterized in that: The following steps are involved: A. Conduct current status survey, measurement and data collection of operating subway tunnels; B. Through numerical three-dimensional inversion calculation, the remaining deformation margin control value of the operating subway tunnel is given, and the bearing capacity margin control value of the tunnel structure is verified; C. Determine the clear distance between the upper and lower tunnels of the newly built superimposed tunnel; D. Determine the plane clearance between the newly built overlapping tunnel and the existing operating subway tunnel; E. Determine the vertical clearance between the newly built overlapping tunnel and the existing operating subway tunnel; F. Determine the reinforcement plan for the stacked shield tunnel; Step A is to conduct current status investigation, measurement and data collection of operating subway tunnels. The specific process is as follows: First, investigate and collect archived construction drawings of operational subway tunnels; Then, the deformation S1 of the operating subway tunnel is measured, and the deformation S1 includes the settlement deformation monitoring data, the lateral deformation monitoring data, and the radial convergence monitoring data; Step B uses numerical three-dimensional inversion calculation to give the remaining deformation margin control value of the operating subway tunnel and verify the tunnel structure bearing capacity margin control value. The specific process is as follows: Firstly, based on the archived construction drawings of the operating subway tunnel, the design bearing capacity and allowable deformation of the operating tunnel were obtained; Then, based on the archived construction drawings of the operating subway tunnel, the Midas three-dimensional numerical calculation model was established to calculate the internal forces of the operating tunnel structure; Then, based on the design bearing capacity and the internal force of the operating tunnel structure, the control value of the tunnel structure bearing capacity margin is obtained; Finally, the remaining deformation margin control value of the operating subway tunnel is obtained based on the allowable deformation of the operating tunnel and the deformation of the operating tunnel.

2. The design method of a stacked shield machine for a long-distance adjacent operating subway tunnel according to claim 1 is characterized by: Based on the archived construction drawings of the operating subway tunnel, the design bearing capacity and allowable deformation of the operating tunnel are obtained. The specific process is as follows: First, check the segment type and reinforcement form of the operating tunnel according to the archived construction drawings of the operating subway tunnel; Then, the design bearing capacity F is obtained, which includes bending moment, axial force and shear force; Finally, the allowable operational tunnel deformation S is obtained.

3. The design method of a stacked shield machine for a long-distance adjacent operating subway tunnel according to claim 2 is characterized in that: The allowed deformation S of the operating tunnel includes settlement deformation of the subway tunnel, lateral deformation of the operating subway tunnel, and radial convergence of the operating subway tunnel.

4. The design method of a stacked shield for a long-distance adjacent operating subway tunnel according to claim 2 is characterized in that: Based on the archived drawings of the construction of the operating subway tunnel, the Midas three-dimensional numerical calculation model was established to calculate the internal forces of the operating tunnel structure. The specific process is as follows: Firstly, a MIDAS three-dimensional numerical calculation model was established based on the archived construction drawings of the operating subway tunnel; Then, the deformation S1 of the operating subway tunnel, i.e., the settlement deformation monitoring data, the lateral deformation monitoring data, and the radial convergence monitoring data, are applied to the operating subway tunnel as additional displacement deformation; Finally, the internal force F1 of the operating tunnel structure is calculated.

5. The design method of a stacked shield machine for a long-distance adjacent operating subway tunnel according to claim 4 is characterized in that: The control value of the tunnel structure bearing capacity margin is F0=F-F1; the control value of the operating subway tunnel residual deformation margin is S0=S-S1.

6. The design method of a stacked shield for a long-distance adjacent operating subway tunnel according to claim 1 is characterized by: Step C determines the clearance between the upper and lower tunnels of the newly built superimposed tunnel. The specific process is as follows: First, determine the construction sequence of the upper and lower tunnels of the new overlapping tunnel; Then, determine the construction distance between the upper and lower tunnels of the newly built overlapping tunnel; Finally, determine the net distance between the upper and lower holes of the newly built stacked tunnel.

7. The design method of a stacked shield machine for a long-distance adjacent operating subway tunnel according to claim 1 is characterized by: Step D determines the plane clearance between the newly built overlapping tunnel and the existing operating subway tunnel. The specific process is as follows: First, it is assumed that the vertical clearance L between the upper tunnel of the newly built superimposed tunnel and the operating subway tunnel is 0; Then, based on the Midas three-dimensional numerical calculation model in step B, a new stacked tunnel is added, and the plane distances of the new stacked tunnel are respectively multiple groups; Then, after adding the newly built superimposed tunnel, the additional internal forces of the operating subway tunnel structure are extracted respectively; After that, after adding the newly built overlapping tunnel, the deformation value of each operating tunnel is added; Finally, the power function is used to simulate the curve function of the plane clearance D and the additional internal force of the operating subway tunnel structure and the additional deformation value of the operating tunnel, and the plane clearance D0 at the inflection point of the curve is obtained by curve fitting.

8. The design method of a stacked shield machine for a long-distance adjacent operating subway tunnel according to claim 7 is characterized in that: Step E determines the vertical clearance between the newly built superimposed tunnel and the existing operating subway tunnel. The specific process is as follows: First, based on step D, the plane clearance D0 is obtained; Then, establish multiple groups of vertical clearances between the upper tunnel of the newly built superimposed tunnel and the operating subway tunnel; Then, according to the three-dimensional numerical calculation results, the additional internal forces of the operating subway tunnel structure are extracted respectively; Then, according to the three-dimensional numerical calculation results, the additional deformation values ​​of the operating tunnels were extracted respectively; Finally, the power function is used to simulate the curve function of the vertical clearance L and the additional internal force of the operating subway tunnel structure and the additional deformation value of the operating tunnel. The vertical clearance L0 is obtained by curve fitting. Here, the additional internal force of the operating subway tunnel structure is greater than the control value of the tunnel structure bearing capacity margin, and the additional deformation value is greater than the control value of the remaining deformation margin of the operating subway tunnel.

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