Automatic fine simulation method for bolt connection of shield tunnel segment

Abstract

An automated and refined simulation method for bolted connections of shield tunnel segments is proposed. This method realistically simulates the stress conditions of shield tunnel lining and the bolted connections of shield tunnel segments, achieving refined automation of the bolted connection process. It eliminates the need to manually locate connection locations and set connection attributes, quickly and accurately establishing a shield tunnel segment connection model that conforms to real-world stress conditions. This provides a basis for studying the response of shield tunnels under loads and deformations. The method includes the following steps: generating a numerical calculation model; excavating the tunnel, setting up the first ring of segment lining, and generating a shield tunnel lining model; setting up circumferential connections of shield tunnel segments; setting up the second ring of segment lining and longitudinal connections of shield tunnel segments; repeating the excavation and numerical calculation model calculations; and repeating the aforementioned steps using the FILE language until the entire tunnel excavation and connection unit setup are automated.

Description

Technical Field

[0001] This invention belongs to the technical field of shield tunnel mechanics research in civil and transportation engineering, and specifically relates to an automatic and refined simulation method for bolted connections of shield tunnel segments. Background Technology

[0002] Shield tunneling has been widely used in the subway construction boom in many cities due to its advantages such as minimal environmental impact, no limitation by terrain or topography, and safe and rapid construction.

[0003] Shield tunnel lining typically employs circumferential joints to splice multiple arc-shaped lining segments into segment rings, which are then assembled into a complete tunnel using longitudinal joints, either with continuous or staggered joints. The mechanical behavior of the segment joints in a shield tunnel under load affects the mechanical characteristics of the entire tunnel structure, and the nonlinear characteristics generated by the joints complicate the overall mechanical mechanism of the shield tunnel.

[0004] Compared to laboratory experiments, numerical simulation methods are less expensive and have a shorter timeframe, which is beneficial for the development of shield tunnel research. Therefore, establishing a shield tunnel segment bolt connection model in numerical simulation software that conforms to real stress conditions is extremely important for the development and in-depth research of shield tunnels. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide an automatic and refined simulation method for bolted connections of shield tunnel segments, which can realistically simulate the stress conditions of shield tunnel lining and the bolted connections of shield tunnel segments. This method achieves refined automation of the bolted connection process, eliminating the need to find each connection location and set connection attributes individually. It can quickly and accurately establish a shield tunnel segment connection model that conforms to the actual stress conditions, providing a basis for studying the response of shield tunnels under loads and deformations.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] This invention discloses an automated and refined simulation method for bolted connections of tunnel segments, comprising the following steps:

[0008] S1. Generate numerical calculation model: The model is established using numerical simulation software. The plane size and length of the model are selected based on the range of the surrounding soil layers affected by the tunnel excavation. The numerical calculation model and its mechanical parameters and boundary conditions are set. After the numerical calculation model is initially balanced, the displacement is cleared and displacement and stress monitoring points are set.

[0009] S2. Excavate the tunnel and install the first ring of tunnel segments, and generate a shield tunnel lining model: Excavate the tunnel and install the first ring of tunnel segments according to the numerical calculation model size set in step S1. Simulate shield tunnel segments through lining units. Assign different identification numbers to lining units at different locations to form independent segments. Set a new local coordinate system for the lining unit, with its y-axis pointing to the tunnel shield's forward direction, z-axis pointing to the tunnel's radial centerline, and x-axis being the tangent of the lining plane.

[0010] S3. Set up circumferential connections for shield tunnel segments: Delete the original node-soil type connections that existed at the adjacent positions of two adjacent segments in the same ring lining. Then, establish a new node-node type circumferential connection at the deleted position. Set the spring model and its parameters connected in six degrees of freedom according to the bolt connection situation.

[0011] S4. Set the second ring segment lining and the longitudinal connection of the shield tunnel segments: Excavate the second circular tunnel and set the second ring segment lining. Then delete the original part of the node-stratum type connection at the adjacent position of the two adjacent ring segment linings. At the deleted position, establish a new node-node type longitudinal connection. Set the spring model and its parameters of the connection in six degrees of freedom according to the bolt connection situation.

[0012] S5. Repeated excavation and numerical calculation model calculation: After calculating a certain number of steps based on the time interval between the excavation of two adjacent ring linings, monitor the displacement and internal force on each node; and repeat steps S1, S2, S3, and S4 through the fish language until the entire tunnel excavation and connection unit setting are completed automatically.

[0013] The beneficial effects of this invention are mainly reflected in the following aspects:

[0014] I. To realistically simulate the stress conditions of shield tunnel lining with relatively weak segment bolt connections, based on the FISH language in numerical simulation software, the bolt connections of shield tunnel segments were realistically simulated, realizing the automation of the shield tunnel bolt connection process. It eliminates the need to find the connection position and set the connection attributes one by one, and can quickly and accurately establish a shield tunnel segment connection model that conforms to the real stress conditions, providing a basis for studying the response of shield tunnels under load and deformation.

[0015] Third, the use of automated model building greatly improves modeling efficiency, is simple to operate, and is easy to apply in practice, providing a reasonable model for studying the deformation and internal forces of shield tunnel lining.

[0016] Fourth, compared with indoor experiments, numerical simulation methods are less expensive and have a shorter cycle, which is beneficial to the development of shield tunnel research. Attached Figure Description

[0017] Figure 1 A flowchart for establishing the bolt connection model of the shield tunnel of the present invention;

[0018] Figure 2 This is a schematic diagram of a three-dimensional model of the lining segments of the present invention;

[0019] Figure 3 This is a schematic diagram of the longitudinal and circumferential bolt connection model of the lining segments of the present invention;

[0020] Figure 4 A schematic diagram showing the deformation spring installed in the circumferential connection unit of the lining segment of the present invention;

[0021] Figure 5 A schematic diagram showing the deformation spring installed in the longitudinal connection unit of the lining segment of the present invention.

[0022] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: first ring segment lining 1, first segment 11, circumferential connection first node 111, longitudinal connection first node 112, second segment 12, circumferential connection second node 121, second ring segment lining 2, third segment 21, longitudinal connection second node 211, fourth segment 22, circumferential connection of segments 3, longitudinal connection of segments 4, bending spring 5, compression spring 6, shear spring 7. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0024] Reference Figure 1 This paper presents an automated and refined simulation method for bolted connections of shield tunnel segments, comprising the following steps:

[0025] S1. Generate numerical calculation model: The model is established using numerical simulation software. The plane size and length of the model are selected based on the range of the surrounding soil layers affected by the tunnel excavation. The numerical calculation model and its mechanical parameters and boundary conditions are set. After the numerical calculation model is initially balanced, the displacement is cleared and displacement and stress monitoring points are set.

[0026] S2. Excavate the tunnel and install the first ring of tunnel segments, and generate a shield tunnel lining model: Excavate the tunnel and install the first ring of tunnel segments according to the numerical calculation model size set in step S1. Simulate shield tunnel segments through lining units. Assign different identification numbers to lining units at different locations to form independent segments. Set a new local coordinate system for the lining unit, with its y-axis pointing to the tunnel shield's forward direction, z-axis pointing to the tunnel's radial centerline, and x-axis being the tangent of the lining plane.

[0027] S3. Set up circumferential connections for shield tunnel segments: Delete the original node-soil type connections that existed at the adjacent positions of two adjacent segments in the same ring lining. Then, establish a new node-node type circumferential connection at the deleted position. Set the spring model and its parameters connected in six degrees of freedom according to the bolt connection situation.

[0028] S4. Set the second ring segment lining and the longitudinal connection of the shield tunnel segments: Excavate the second circular tunnel and set the second ring segment lining. Then delete the original part of the node-stratum type connection at the adjacent position of the two adjacent ring segment linings. At the deleted position, establish a new node-node type longitudinal connection. Set the spring model and its parameters of the connection in six degrees of freedom according to the bolt connection situation.

[0029] S5. Repeated excavation and numerical calculation model calculation: After calculating a certain number of steps based on the time interval between the excavation of two adjacent ring linings, monitor the displacement and internal force on each node; and repeat steps S1, S2, S3, and S4 through the fish language until the entire tunnel excavation and connection unit setting are completed automatically.

[0030] In the above technical solution:

[0031] The soil layer selection for the numerical calculation model described in step S1 is the Mohr-Coulomb model;

[0032] In step S2, the lining unit retains some joints that are connected to the soil layer;

[0033] The new circumferential connection described in step S3 is a spring model and its parameters in six degrees of freedom, including stiffness, internal friction angle, cohesion and yield strength;

[0034] The new longitudinal connection described in step S4 is a spring model and its parameters in six degrees of freedom, including spring stiffness, internal friction angle, cohesion and yield strength.

[0035] In step S3, the new circumferential connection is provided with a bending spring in the y-direction, a compression spring in the x-direction, and a shear spring in the z-direction.

[0036] In step S4, the new longitudinal connection is provided with a compression spring in the y direction, a bending spring in the x direction, and a shear spring in the z direction.

[0037] Example:

[0038] Reference Figures 1 to 5 The steps of the automatic and refined simulation method for bolted connections of shield tunnel segments according to the present invention in this embodiment are as follows:

[0039] S1. Generate a numerical calculation model.

[0040] Numerical simulation software was used to establish a numerical calculation model. The model's planar dimensions and length were selected based on the extent to which the tunnel excavation would affect the surrounding soil layers. The numerical calculation model and its mechanical parameters and boundary conditions were set according to the actual situation. Specifically, the dimensions of the numerical calculation model were assumed to be: a cross-section length of 200m and a height of 100m, with a length of 100m along the longitudinal direction; the tunnel was a circular cross-section with a radius of 5, and each excavation depth was 5m; the soil layer was uniform soft clay, conforming to the Mohr-Coulomb strength theory, with a bulk modulus and tangential modulus of 50MPa and 18MPa, respectively; the friction angle was 20°; the internal cohesion was 50KPa; the loads applied were gravity load and a uniform top load; and the boundary conditions were displacement boundary conditions. After the numerical calculation model reached initial equilibrium, the displacement was cleared, and displacement and stress monitoring points were set.

[0041] S2. Excavate the tunnel and install the first ring of segment lining, and generate a shield tunnel lining model:

[0042] According to the numerical calculation model dimensions set in S1, the tunnel is excavated and the first ring of segment lining 1 is installed. The lining units simulate the segment lining of a shield tunnel. By assigning different identification numbers to lining units at different locations, they are divided into independent segments. Each ring of segments is formed by connecting different segments using circumferential connecting units. Adjacent rings of segment lining are connected together by longitudinal connecting units to form a complete tunnel model. Specifically, the first section of the circular tunnel is excavated (a section of the circular tunnel is excavated every 5m) and the first ring of segment lining 1 is installed, as follows... Figure 2 and Figure 3 As shown, the shield tunnel segment lining system includes a first ring segment lining 1, a second ring segment lining 2, ..., an Nth ring segment lining connected longitudinally in sequence; the first ring segment lining 1 includes a first segment 11 and a second segment 12 connected circumferentially in sequence; the first segment 11 and the second segment 12 are connected by a segment circumferential connection 3; the second ring segment lining 2 includes a third segment 21 and a fourth segment 22 connected circumferentially in sequence; the third segment 21 and the fourth segment 22 are connected by a segment circumferential connection unit 3; the first segment 11 and the third segment 21 are connected by a segment longitudinal connection unit 4, and the second segment 12 and the fourth segment 22 are also connected by a segment longitudinal connection unit 4; as shown Figure 2 As shown, a new local coordinate system is set for the lining unit: the y-axis points to the direction of tunnel shield advance, the z-axis points to the radial centerline of the tunnel, and the x-axis is the tangent of the lining plane.

[0043] S3. Set up circumferential connections for shield tunnel segments:

[0044] Delete the original node-soil type connections at adjacent positions between two adjacent segments in the same ring lining. Then, establish a new node-node type circumferential connection at the deleted position (e.g., Figure 4 The first node 111 of the circumferential connection (to the second node 121 of the circumferential connection) is shown. The spring models and their parameters for this first connection in six degrees of freedom are set, including stiffness E, internal friction angle φ, cohesion c, yield strength, etc. Specifically, a bending spring 5 is set in the y-direction of the new circumferential connection, a compression spring 6 is set in the x-direction, and a shear spring 7 is set in the z-direction. The spring type is selected as linear springs, and the stiffnesses are represented by KR, KC, and KT respectively. The other directions are set as rigid connections. The parameters of the deformable springs are set according to the bolted connection, such as stiffness E, internal friction angle φ, cohesion c, yield strength, etc. Figure 4 As shown, the bending spring 5, the compression spring 6, and the shear spring 7 are all disposed between the first circumferential connection node 111 on the first tube segment 11 and the second circumferential connection node 121 on the second tube segment 12; the compression spring 6 and the shear spring 7 are arranged perpendicular to each other; the two ends of the bending spring 5 are respectively connected to the first circumferential connection node 111 and the second circumferential connection node 121.

[0045] S4. Install the second ring segment lining and longitudinal connection of shield tunnel segments:

[0046] A second circular tunnel section is excavated 5 meters away from the first circular tunnel section, and a second ring of segment lining is installed. Starting from the second ring of segment lining, each new ring of segments will establish a new connection with the previous ring of segment lining to simulate a longitudinal bolted connection; such as Figure 5 As shown, firstly, some existing node-soil type connections at adjacent positions of the lining of two adjacent ring segments are deleted. Then, a new longitudinal connection of node-node type is established at the deleted position (e.g., Figure 5 The longitudinal connection from node 112 to node 122 (shown) is configured with spring models and parameters in six degrees of freedom, including stiffness E, internal friction angle φ, cohesion c, and yield strength. Specifically, a compression spring 6, a bending spring 5, and a shear spring 7 are set in the x-direction, y-direction, and z-direction of the second node connection unit, respectively. The spring type is selected as linear springs, and the stiffnesses are represented by KR, KC, and KT. The remaining directions are set as rigid connections. The parameters of the deformable springs, such as stiffness E, internal friction angle φ, cohesion c, and yield strength, are set according to the bolt connection. Figure 5As shown, the bending spring 5, the compression spring 6, and the shear spring 7 are all located between the first longitudinal connection node 112 on the first tube segment 11 and the second longitudinal connection node 211 on the third tube segment 21; the compression spring 6 and the shear spring 7 are arranged perpendicular to each other; the two ends of the bending spring 5 are respectively connected to the first longitudinal connection node 112 and the second longitudinal connection node 122.

[0047] Step 5, S5, repeated excavation, numerical calculation model calculation:

[0048] After the new circumferential and longitudinal connections are set in steps 3 and 4, a certain number of steps are calculated based on the time interval between the excavation of two adjacent ring linings, and the displacement and internal force on each node are monitored. Steps 1, 2, 3 and 4 are repeated using the fish language, thereby realizing the automated processing of the entire tunnel excavation and connection unit setting.

[0049] This invention provides an automated and refined simulation method for bolted connections of tunnel segments in shield tunnels. Compared to laboratory experiments, numerical simulation methods are less costly and have a shorter cycle time, which is beneficial to the development of shield tunnel research. For the relatively weak bolted connections of tunnel segments, this method realistically simulates the stress conditions of the shield tunnel lining. Based on the FILE language in the simulation calculation unit, it realistically simulates the bolted connections of shield tunnel segments, automating the bolted connection process. It eliminates the need to find each connection location and set connection attributes individually, and can quickly and accurately establish a shield tunnel segment connection model that conforms to the actual stress conditions. This provides a basis for studying the response of shield tunnels under loads and deformations. Its automated model building method greatly improves modeling efficiency, and the invention is simple to operate and easy to apply in practice, providing a reasonable model for studying the deformation and internal forces of shield tunnel linings.

Claims

1. An automated and refined simulation method for bolted connections of tunnel segments, comprising the following steps: S1. Generate numerical calculation model: The model is established using numerical simulation software. The plane size and length of the model are selected based on the range of the surrounding soil layers affected by the tunnel excavation. The numerical calculation model and its mechanical parameters and boundary conditions are set. After the numerical calculation model is initially balanced, the displacement is cleared and displacement and stress monitoring points are set. S2. Excavate the tunnel and install the first ring of tunnel segments, and generate a shield tunnel lining model: Excavate the tunnel and install the first ring of tunnel segments according to the numerical calculation model size set in step S1. Simulate shield tunnel segments through lining units. Assign different identification numbers to lining units at different locations to form independent segments. Set a new local coordinate system for the lining unit, with its y-axis pointing to the tunnel shield's forward direction, z-axis pointing to the tunnel's radial centerline, and x-axis being the tangent of the lining plane. S3. Set up circumferential connections for shield tunnel segments: Delete the original node-soil type connections that existed at the adjacent positions of two adjacent segments in the same ring lining. Then, establish a new node-node type circumferential connection at the deleted position. Set the spring model and its parameters connected in six degrees of freedom according to the bolt connection situation. S4. Set the second ring segment lining and the longitudinal connection of the shield tunnel segments: Excavate the second circular tunnel and set the second ring segment lining. Then delete the original part of the node-stratum type connection at the adjacent position of the two adjacent ring segment linings. At the deleted position, establish a new node-node type longitudinal connection. Set the spring model and its parameters of the connection in six degrees of freedom according to the bolt connection situation. S5. Repeated excavation and numerical calculation model calculation: After calculating a certain number of steps based on the time interval between the excavation of two adjacent ring linings, monitor the displacement and internal force on each node; and repeat steps S1, S2, S3, and S4 through the fish language until the entire tunnel excavation and connection unit setting are completed automatically.

2. The method of claim 1, wherein the method is characterized by: The soil layer selection for the numerical calculation model described in step S1 is the Mohr-Coulomb model.

3. The automatic and refined simulation method for bolted connections of shield tunnel segments as described in claim 1, characterized in that: In step S2, the lining unit retains some nodes connected to the soil layer.

4. The automatic and refined simulation method for bolted connections of shield tunnel segments as described in claim 1, characterized in that: The new circumferential connection described in step S3 is a spring model and its parameters in six degrees of freedom, including stiffness, internal friction angle, cohesion and yield strength.

5. The automatic and refined simulation method for bolted connections of shield tunnel segments as described in claim 1, characterized in that: The new longitudinal connection described in step S4 is a spring model and its parameters in six degrees of freedom, including spring stiffness, internal friction angle, cohesion and yield strength.

6. The automatic and refined simulation method for bolted connections of shield tunnel segments as described in claim 1, characterized in that: In step S3, the new circumferential connection is provided with a bending spring in the y-direction, a compression spring in the x-direction, and a shear spring in the z-direction.

7. The automatic and refined simulation method for bolted connections of shield tunnel segments as described in claim 1, characterized in that: In step S4, the new longitudinal connection is provided with a compression spring in the y direction, a bending spring in the x direction, and a shear spring in the z direction.

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