Submarine tunnel full life cycle supergravity simulation method

Abstract

The invention discloses a subsea tunnel full life cycle supergravity simulation method, which comprises the following steps: firstly, constructing a supergravity test physical model, calibrating a phase field function, and simultaneously constructing a two-phase flow model of a subsea tunnel in a supergravity environment based on a continuity equation, a momentum conservation equation and a phase field equation; and then initializing a two-phase flow model based on the calibrated phase-field function, performing loop iteration of the two-phase flow model, completing change updating of the full life cycle of the subsea tunnel in the supergravity environment, and realizing iterative simulation of the full life cycle change condition of the tunnel in the constant gravity environment. According to the method, the landslide process is reproduced through physical simulation in the supergravity environment, structural response is analyzed by means of calculation of a numerical model, and the landslide action mechanism and the tunnel failure mode are further systematically revealed.

Description

Technical Field

[0001] This invention relates to the field of submarine tunnel technology, specifically a method for simulating the entire life cycle of a submarine tunnel under hypergravity. Background Technology

[0002] Faced with the turbulent currents and extremely complex geological conditions of the seabed environment, engineers must confront the severe challenges posed by various geological hazards, especially the potential risk of submarine landslides, which are sudden, highly destructive, and pose a direct and serious threat to the deeply buried shield tunnel structure. In severe cases, it can cause cracks in the tunnel structure, and in cases of severe water seepage, it can lead to structural collapse. Therefore, how to accurately assess and effectively mitigate its impact has become a core scientific problem and technical bottleneck that must be solved in the design and safe operation and maintenance of submarine tunnels. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a hypergravity simulation method for the entire life cycle of a submarine tunnel. Under hypergravity conditions, the landslide process is reproduced through physical simulation, and the structural response is analyzed by numerical model calculation, so as to further systematically reveal the landslide mechanism and tunnel failure mode.

[0004] The technical solution of this invention is as follows: A method for simulating the entire life cycle of an undersea tunnel under hypergravity conditions includes the following steps: (1) Construct a physical model for the hypergravity experiment to calibrate the phase field function. The specific formula for calculating the phase field function is shown in the following formula (1): (1); In equation (1), Represents the phase field function, i.e., the phase field variable; This represents the supergravity factor, which is the ratio of supergravity acceleration to gravitational acceleration. This represents the vibration adjustment coefficient, with a value range of 0.85 to 0.96. Represents the hyperbolic tangent function; Represents spatial coordinates, The horizontal coordinates represent the direction of tunnel movement. Representative and The horizontal coordinate in the vertical direction; Represents amplitude; Represents time; Represents spatial frequency; Represents angular frequency; Represents the initial phase; Represents interface thickness; the interface thickness mentioned above Amplitude A and angular frequency Real-time data acquisition through hypergravity experiments; (2) Construct a two-phase flow model of a submarine tunnel under hypergravity. The two-phase flow model is based on the continuity equation, the momentum conservation equation and the phase field equation. (3) Initialize the two-phase flow model based on the calibrated phase field function: Initialize the fluid velocity field Fluid pressure field and phase field variables Phase field variables Calculated from equation (1), based on the initialized phase field variables Update the density at each point in the two-phase flow model. Dynamic viscosity and supergravity multiple ; (4) Iterative two-phase flow model: update the density Dynamic viscosity Gravitational acceleration factor and interfacial stress Substituting the continuity equation and the momentum conservation equation, the new fluid velocity field is solved. and fluid pressure field Then the new fluid velocity field Substitute into the phase field equation to calculate the new phase field variables. The value at the next time step; (5) After the two-phase flow model completes its iterative cycle, the two-phase flow model after the iteration is output, that is, the changes of the fluid velocity field, fluid pressure field and phase field function throughout the entire life cycle are updated. Thus, based on the scaling and time-reduction effect of the two-phase flow model of the submarine tunnel under hypergravity, the changes of the tunnel throughout the entire life cycle under normal gravity are iteratively simulated.

[0005] The physical model for the hypergravity test includes a shaking table and a model box fixed on the shaking table. A seabed model is set in the lower part of the model box, a tunnel model is buried in the seabed model, and the upper part of the model box is filled with seawater. When calibrating the phase field function in real time through a hypergravity experiment, the vibration table and model box are placed in the basket of the hypergravity centrifuge. The hypergravity centrifuge is then started to conduct the hypergravity experiment. The amplitude A is obtained through real-time vibration control of the vibration table, and the angular frequency... Interface thickness was obtained by controlling the hypergravity factor using a hypergravity centrifuge. The deformation of the seabed model interface before and after the hypergravity experiment was collected, and the deformation was inverted using the finite element simulation inversion method.

[0006] The continuity equation is shown in equation (2) below: (2); In equation (2), Represents the multiple of supergravity; This represents the hypergravity adjustment factor, with a value ranging from 0.85 to 1.2. Represents density; Represents the fluid velocity field; This represents the gradient operator.

[0007] The momentum conservation equation is shown in equation (3) below: (3); In equation (3), Represents the multiple of supergravity; Represents density; Represents the fluid velocity field; Represents time; Represents the gradient operator; This represents the reduction factor, with a value ranging from 0.97 to 1.12. Represents the fluid pressure field; Representative unit: Zhang Liang; Represents the dynamic viscosity of a fluid; This represents the additional load caused by hypergravity. It represents gravitational acceleration.

[0008] The phase-field equations are shown in equation (4) below: (4); In equation (4), Represents phase field variables; Represents time; Represents the gradient operator; Represents the fluid velocity field; The adjustment factor representing the chemical potential ranges from 4.51 to 5.62. This represents the mass migration adjustment parameter, with a value range of 0.0001 to 0.00001. ; Chemical potential of a representative species in a specific phase; The interfacial stress is represented by the following formula (5): (5); In equation (5), Surface tension in the XY plane direction The surface tension in the XZ plane direction. Surface tension in the YZ plane direction.

[0009] The two-phase flow model cycle iteration ends when the cycle ends. That is, before the two-phase flow model cycle iteration, the end time point of the entire life cycle is set. When the cycle iteration time of the two-phase flow model reaches the end time point, the cycle iteration of the two-phase flow model ends.

[0010] Advantages of this invention: (1) Gravity geotechnical engineering test, also known as centrifuge model test, is a revolutionary physical simulation technology in the field of geotechnical engineering. Its core principle is to use a supergravity centrifuge to generate a supergravity environment that is much greater than the Earth's gravity, so as to reproduce the real stress state of the full-size prototype structure in a scaled model, thereby revealing the mechanical behavior and failure mechanism of the soil and rock under external load, water level change, earthquake and various disaster conditions. Based on the scaled and time-reduction effect of the two-phase flow model of the submarine tunnel under supergravity, this invention iteratively simulates the changes of the tunnel throughout its entire life cycle under normal gravity.

[0011] (2) The two-phase flow model of the submarine tunnel under hypergravity constructed in this invention is based on the continuity equation, momentum conservation equation, and phase field equation, and the phase field function. Calibration was performed by constructing a physical model for a hypergravity experiment, and the phase field function was determined. Its function is to accurately track the interface information between seawater and the seabed (i.e., landslide body), and this interface information is fed back to the momentum conservation equation; at the interface, the density and dynamic viscosity of the fluid change drastically, and the momentum conservation equation is based on the phase field function. This determines whether each point belongs to the fluid phase (seawater) or the solid phase (seabed), thus applying the corresponding material properties; simultaneously, the momentum conservation equation provides the convective velocity for the phase field equation: the fluid velocity field obtained by solving the momentum equation. The convection term will be substituted into the phase field equations. In this context, it refers to the fact that the movement of fluids (such as undersea currents or flows generated by landslides) can scour, carry, and distort the fluid-solid interface. The continuity equation and the momentum conservation equation are solved simultaneously to obtain the flow field (velocity field and pressure field) that satisfies mass conservation (continuity equation) and force balance (momentum conservation equation). That is, the fluid velocity field generated in the momentum conservation equation must satisfy the constraints of the continuity equation. Attached Figure Description

[0012] Figure 1 This is a flowchart of the present invention.

[0013] Figure 2 This is a schematic diagram of the physical model for the hypergravity experiment of this invention.

[0014] Attached labels: 1-vibration table, 2-model box, 3-seabed model, 4-tunnel model, 5-seawater. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] See Figure 1 A method for simulating the entire life cycle of an undersea tunnel under hypergravity includes the following steps: (1) Construct a physical model for the hypergravity experiment to calibrate the phase field function. The specific formula for calculating the phase field function is shown in the following formula (1): (1); In equation (1), Represents the phase field function, i.e., the phase field variable; This represents the supergravity factor, which is the ratio of supergravity acceleration to gravitational acceleration. This represents the vibration adjustment coefficient, with a value range of 0.85 to 0.96. Represents the hyperbolic tangent function; Represents spatial coordinates, The horizontal coordinates represent the direction of tunnel movement. Representative and The horizontal coordinate in the vertical direction; Represents amplitude; Represents time; Represents spatial frequency; Represents angular frequency; Represents the initial phase; Represents interface thickness; Interface thickness Amplitude A and angular frequency Real-time data acquisition through hypergravity experiments; (2) Construct a two-phase flow model of a submarine tunnel under hypergravity. The two-phase flow model is based on the continuity equation, the momentum conservation equation and the phase field equation. The continuity equation is shown in equation (2) below: (2); In equation (2), Represents the multiple of supergravity; This represents the hypergravity adjustment factor, with a value ranging from 0.85 to 1.2. Represents density; Represents the fluid velocity field; Represents the gradient operator; The specific equation for the conservation of momentum is shown in equation (3) below: (3); In equation (3), Represents the multiple of supergravity; Represents density; Represents the fluid velocity field; Represents time; Represents the gradient operator; This represents the reduction factor, with a value ranging from 0.97 to 1.12. Represents the fluid pressure field; Representative unit: Zhang Liang; Represents the dynamic viscosity of a fluid; This represents the additional load caused by hypergravity. Represents gravitational acceleration; The phase field equation is shown in equation (4) below: (4); In equation (4), Represents phase field variables; Represents time; Represents the gradient operator; Represents the fluid velocity field; The adjustment factor representing the chemical potential ranges from 4.51 to 5.62. This represents the mass migration adjustment parameter, with a value range of 0.0001 to 0.00001. ; Chemical potential of a representative species in a specific phase; The interfacial stress is represented by the following formula (5): (5); In equation (5), Surface tension in the XY plane direction The surface tension in the XZ plane direction. Surface tension in the YZ plane direction; (3) Initialize the two-phase flow model based on the calibrated phase field function: Initialize the fluid velocity field Fluid pressure field and phase field variables Phase field variables Calculated from equation (1), based on the initialized phase field variables Update the density at each point in the two-phase flow model. Dynamic viscosity and supergravity multiple ; (4) Iterative two-phase flow model: update the density Dynamic viscosity Gravitational acceleration factor and interfacial stress Substituting the continuity equation and the momentum conservation equation, the new fluid velocity field is solved. and fluid pressure field Then the new fluid velocity field Substitute into the phase field equation to calculate the new phase field variables. The value at the next time step; (5) After the two-phase flow model completes its iterative cycle (reaches the set end time point), the two-phase flow model after the iteration is completed is output, that is, the changes of the fluid velocity field, fluid pressure field and phase field function throughout the entire life cycle are updated. Thus, based on the scaling and time-reduction effect of the two-phase flow model of the submarine tunnel under hypergravity, the changes of the tunnel throughout the entire life cycle under normal gravity are iteratively simulated.

[0017] See Figure 2 The physical model for the hypergravity test includes a shaking table 1 and a model box 2 fixed on the shaking table 1. A seabed model 3 is set in the lower part of the model box 2, a tunnel model 4 is buried in the seabed model 3, and the upper part of the model box 1 is filled with seawater 5. When calibrating the phase field function in real time through a hypergravity experiment, the vibration table 1, together with the model box 2, is placed in the basket of the hypergravity centrifuge. The hypergravity centrifuge is then started to conduct the hypergravity experiment. The amplitude A is obtained through the real-time vibration control of the vibration table, and the angular frequency... Interface thickness was obtained by controlling the hypergravity factor using a hypergravity centrifuge. The deformation of the seabed model interface before and after the hypergravity experiment was collected, and the deformation was inverted using the finite element simulation inversion method.

[0018] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for simulating the entire life cycle of an undersea tunnel under hypergravity, characterized in that: Specifically, it includes the following steps: (1) Construct a physical model for the hypergravity experiment to calibrate the phase field function. The specific formula for calculating the phase field function is shown in the following formula (1): （1）； In equation (1), Represents the phase field function, i.e., the phase field variable; This represents the supergravity factor, which is the ratio of supergravity acceleration to gravitational acceleration. This represents the vibration adjustment coefficient, with a value range of 0.85 to 0.

96. Represents the hyperbolic tangent function; Represents spatial coordinates, The horizontal coordinates represent the direction of tunnel movement. Representative and The horizontal coordinate in the vertical direction; Represents amplitude; Represents time; Represents spatial frequency; Represents angular frequency; Represents the initial phase; Represents interface thickness; the interface thickness mentioned above Amplitude A and angular frequency Real-time data acquisition through hypergravity experiments; (2) Construct a two-phase flow model of a submarine tunnel under hypergravity. The two-phase flow model is based on the continuity equation, the momentum conservation equation and the phase field equation. (3) Initialize the two-phase flow model based on the calibrated phase field function: Initialize the fluid velocity field Fluid pressure field and phase field variables Phase field variables Calculated from equation (1), based on the initialized phase field variables Update the density at each point in the two-phase flow model. Dynamic viscosity and supergravity multiple ; (4) Iterative two-phase flow model: update the density Dynamic viscosity Gravitational acceleration factor and interfacial stress Substituting the continuity equation and the momentum conservation equation, the new fluid velocity field is solved. and fluid pressure field Then the new fluid velocity field Substitute into the phase field equation to calculate the new phase field variables. The value at the next time step; (5) After the two-phase flow model completes its iterative cycle, the two-phase flow model after the iteration is output, that is, the changes of the fluid velocity field, fluid pressure field and phase field function throughout the entire life cycle are updated. Thus, based on the scaling and time-reduction effect of the two-phase flow model of the submarine tunnel under hypergravity, the changes of the tunnel throughout the entire life cycle under normal gravity are iteratively simulated.

2. The method for simulating the entire life cycle of a submarine tunnel under hypergravity as described in claim 1, characterized in that: The physical model for the hypergravity test includes a shaking table and a model box fixed on the shaking table. A seabed model is set in the lower part of the model box, a tunnel model is buried in the seabed model, and the upper part of the model box is filled with seawater. When calibrating the phase field function in real time through a hypergravity experiment, the vibration table and model box are placed in the basket of the hypergravity centrifuge. The hypergravity centrifuge is then started to conduct the hypergravity experiment. The amplitude A is obtained through real-time vibration control of the vibration table, and the angular frequency... Interface thickness was obtained by controlling the hypergravity factor using a hypergravity centrifuge. The deformation of the seabed model interface before and after the hypergravity experiment was collected, and the deformation was inverted using the finite element simulation inversion method.

3. The method for simulating the entire life cycle of a submarine tunnel under hypergravity as described in claim 1, characterized in that: The continuity equation is shown in equation (2) below: （2）； In equation (2), Represents the multiple of supergravity; This represents the hypergravity adjustment factor, with a value ranging from 0.85 to 1.

2. Represents density; Represents the fluid velocity field; This represents the gradient operator.

4. The method for simulating the entire life cycle of a submarine tunnel under hypergravity as described in claim 3, characterized in that: The momentum conservation equation is shown in equation (3) below: （3）； In equation (3), Represents the multiple of supergravity; Represents density; Represents the fluid velocity field; Represents time; Represents the gradient operator; This represents the reduction factor, with a value ranging from 0.97 to 1.

12. Represents the fluid pressure field; Representative unit: Zhang Liang; Represents the dynamic viscosity of a fluid; This represents the additional load caused by hypergravity. It represents gravitational acceleration.

5. The method for simulating the entire life cycle of a submarine tunnel under hypergravity as described in claim 4, characterized in that: The phase-field equations are shown in equation (4) below: （4）； In equation (4), Represents phase field variables; Represents time; Represents the gradient operator; Represents the fluid velocity field; The adjustment factor representing the chemical potential ranges from 4.51 to 5.

62. This represents the mass migration adjustment parameter, with a value range of 0.0001 to 0.00001. ; Chemical potential of a representative species in a specific phase; The interfacial stress is represented by the following formula (5): （5）； In equation (5), Surface tension in the XY plane direction The surface tension in the XZ plane direction. Surface tension in the YZ plane direction.

6. The method for simulating the entire life cycle of a submarine tunnel under hypergravity as described in claim 1, characterized in that: The two-phase flow model cycle iteration ends when the cycle ends. That is, before the two-phase flow model cycle iteration, the end time point of the entire life cycle is set. When the cycle iteration time of the two-phase flow model reaches the end time point, the cycle iteration of the two-phase flow model ends.

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