Numerical calculation method for influence of orthogonal shield tunnel detail structure

Abstract

The application discloses a numerical calculation method for influence of orthogonal shield tunnel detail structure, relates to the field of simulating an orthogonal shield tunnel excavation face, and solves the problem of long calculation time or calculation non-convergence and other problems in simulating the influence of shield excavation face instability on the existing orthogonal shield tunnel detail structure, and proposes the following scheme, which comprises the following steps: establishing a first-stage three-dimensional finite element model; performing first-stage three-dimensional finite element simulation calculation to obtain the vertical displacement curve z=f(x) and the horizontal displacement curve y=f(x) of the existing orthogonal shield tunnel; performing second-stage three-dimensional refined finite element modeling; performing second-stage three-dimensional refined finite element modeling; and performing second-stage three-dimensional finite element calculation. The device can effectively improve the calculation efficiency of simulating the influence of shield excavation face instability on the existing orthogonal shield tunnel detail structure and reduce the calculation difficulty.

Description

Technical Field

[0001] This invention relates to the field of simulating the excavation face of orthogonal shield tunnels, and more particularly to a numerical calculation method for the influence of detailed structures of orthogonal shield tunnels. Background Technology

[0002] The shield tunneling method is a fully mechanized construction method in the cut-and-cover method. It involves advancing the shield machine underground, using the shield shell and segments to support the surrounding rock and prevent collapse into the tunnel. At the same time, cutting devices are used to excavate the soil in front of the excavation face, and the soil is transported out of the tunnel by excavation machinery. Jacks are used to pressurize and push the tunnel forward from the rear, and precast concrete segments are assembled to form the tunnel structure.

[0003] In simulating the impact of shield tunnel face instability on the detailed structure of existing orthogonal shield tunnels, the use of a one-time modeling three-dimensional finite element method results in a large number of model entities and elements due to the need to simulate the detailed structure of the shield tunnel, leading to various problems such as excessively long calculation time or non-convergence. Therefore, a numerical calculation method for the impact of orthogonal shield tunnel detailed structure is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a numerical calculation method for the influence of orthogonal shield tunnel detailed structures, which solves the problems of excessively long calculation time or non-convergence in existing simulations of the influence of shield excavation face instability on the detailed structures of existing orthogonal shield tunnels.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a numerical calculation method for the influence of detailed structures in orthogonal shield tunnels, comprising the following steps:

[0006] S1: Based on the background information, establish the first-stage three-dimensional finite element model;

[0007] S2: Perform the first stage of three-dimensional finite element simulation calculation to extract the existing orthogonal shield tunnel vertical displacement curve z=f(x) and horizontal displacement curve y=f(x);

[0008] S3: Perform the second stage of three-dimensional refined finite element modeling, that is, to use refined modeling for orthogonal shield tunnels;

[0009] S4: Apply the vertical and horizontal displacement curves obtained in the first stage to the three-dimensional refined finite model in the second stage;

[0010] S5: Perform the second stage of three-dimensional finite element calculation to obtain the physical and mechanical response laws of existing orthogonal shield tunnel segments, bolts and joints under the instability of the shield excavation face.

[0011] Preferably, in S1, the existing orthogonal shield tunnel is simulated using beam elements embedded in soil elements, satisfying a displacement coordination relationship with the soil elements. The shield excavation face instability is simulated by changing the displacement constraints.

[0012] Preferably, in S3, both the pipe segments and bolts are modeled as solid elements, and the connection between pipe segments is simulated by embedding bolts into the pipe segment elements. At the same time, a contact surface is provided between the pipe segments.

[0013] Preferably, in S3, the normal direction of the contact surface is set to be under compression only and not tension, the tangential direction of the contact surface is set to frictional contact, and the interaction between the pipe segment and the soil is simulated by a soil spring, which is set to be under compression only and not tension.

[0014] Preferably, in step S4, the deformation of each tunnel division unit is coupled to its corresponding center position, and the vertical displacement curve and the horizontal displacement curve are applied to the center line formed by the corresponding centers by applying displacement constraints.

[0015] Compared with related technologies, the numerical calculation method for the influence of orthogonal shield tunnel detailed structure provided by the present invention has the following beneficial effects:

[0016] This invention provides a numerical calculation method for the influence of detailed structures of orthogonal shield tunnels, which can effectively improve the calculation efficiency of simulating the influence of shield excavation face instability on the detailed structures of existing orthogonal shield tunnels and reduce the calculation difficulty. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a three-dimensional finite element model of a numerical calculation method for the influence of orthogonal shield tunnel detailed structure according to the present invention.

[0018] Figure 2 This is a schematic diagram of displacement curves for a numerical calculation method of the influence of orthogonal shield tunnel detailed structure according to the present invention.

[0019] Figure 3 This is a schematic diagram of a three-dimensional refined finite element model of a numerical calculation method for the influence of orthogonal shield tunnel detailed structure according to the present invention. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Example

[0021] Please see Figure 1-3 The present invention provides a technical solution:

[0022] Step 1: Based on the background information, establish the first-stage 3D finite element model, as shown in the attached manual. Figure 1 As shown, the existing orthogonal shield tunnel is simulated using beam elements embedded in soil elements, satisfying displacement compatibility relationships with the soil elements. The shield excavation face instability is simulated by changing the displacement constraints.

[0023] Step 2: Perform the first-stage three-dimensional finite element simulation calculation to extract the existing orthogonal shield tunnel's vertical displacement curve z=f(x) and horizontal displacement curve y=f(x). Schematic diagrams of the vertical and horizontal displacement curves are shown in the attached instruction manual. Figure 2 As shown.

[0024] Step 3: Perform the second stage of refined 3D finite element modeling, that is, apply refined modeling to the orthogonal shield tunnel, as shown in the appendix to the instruction manual. Figure 3 As shown, both the pipe segments and bolts are modeled using solid elements. The connection between pipe segments is simulated by embedding bolts into the pipe segment elements. Contact surfaces are also established between the pipe segments, with the normal direction of the contact surfaces set to be under compression only, and the tangential direction set to frictional contact. The interaction between the pipe segments and the soil is simulated using soil springs, which are set to be under compression only, not tension.

[0025] Step 4: Apply the vertical and horizontal displacement curves obtained in the first stage to the refined 3D finite element model in the second stage. The specific application method is as follows: ① Couple the deformation of each tunnel subdivision element to its corresponding center position; ② Apply the vertical and horizontal displacement curves to the center line formed by the corresponding centers by applying displacement constraints.

[0026] Step 5: Perform the second stage of three-dimensional finite element calculation to obtain the physical and mechanical response laws of existing orthogonal shield tunnel segments, bolts and joints under the instability of the shield excavation face.

[0027] This invention can effectively improve the calculation efficiency of simulating the impact of shield tunneling face instability on the detailed structure of existing orthogonal shield tunnels, and reduce the calculation difficulty.

Claims

1. A numerical calculation method for the influence of detailed structure on orthogonal shield tunnels, characterized in that, Includes the following steps: S1: Based on the background information, establish the first-stage three-dimensional finite element model; S2: Perform the first stage of three-dimensional finite element simulation calculation to extract the existing orthogonal shield tunnel vertical displacement curve z=f(x) and horizontal displacement curve y=f(x); S3: Perform the second stage of three-dimensional refined finite element modeling, that is, to use refined modeling for orthogonal shield tunnels; S4: Apply the vertical and horizontal displacement curves obtained in the first stage to the three-dimensional refined finite model in the second stage; S5: Perform the second stage of three-dimensional finite element calculation to obtain the physical and mechanical response laws of existing orthogonal shield tunnel segments, bolts and joints under the instability of the shield excavation face; In S1, the existing orthogonal shield tunnel is simulated using beam elements, which are embedded in the soil elements and satisfy the displacement coordination relationship with the soil elements. The shield excavation face is simulated to be unstable by changing the displacement constraints. In S3, both the pipe segments and bolts are modeled as solid elements. The connection between pipe segments is simulated by embedding bolts into the pipe segment elements, and a contact surface is set between the pipe segments.

2. The numerical calculation method for the influence of detailed structure of orthogonal shield tunnels according to claim 1, characterized in that, In S3, the normal direction of the contact surface is set to be under compression only and not tension, the tangential direction of the contact surface is set to frictional contact, and the interaction between the pipe segment and the soil is simulated by a soil spring, which is set to be under compression only and not tension.

3. The numerical calculation method for the influence of detailed structure of orthogonal shield tunnels according to claim 1, characterized in that, In S4, the deformation of each tunnel division unit is coupled to its corresponding center position, and the vertical displacement curve and horizontal displacement curve are applied to the center line formed by the corresponding centers by applying displacement constraints.

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