Method and system for predicting temperature field in high-ground-temperature tunnel

Abstract

The invention provides a prediction method and system for a temperature field in a high-ground-temperature tunnel, and belongs to the technical field of tunnel construction.The prediction method comprises the steps that S1, an initial value of the high-ground-temperature tunnel is obtained; s2, building a surrounding rock tunnel model; s3, the surrounding rock tunnel model is set to be in a non-uniform temperature field, and the initial value of the high-ground-temperature tunnel is substituted into the surrounding rock tunnel model to initialize the model; s4, the air flow temperature is set in the initialization model; setting underground seepage water in the initialized model by adopting a Darcy law so as to form a coupling tunnel model after coupling of the surrounding rock, the underground seepage water and the wind current; and S5, predicting a temperature field in the high-ground-temperature tunnel by using the coupling tunnel model. According to the invention, the coupling of surrounding rock, underground seepage water and wind flow is realized, the temperature field distribution in the high-ground-temperature tunnel is simulated, and the potential risk existing in the high-ground-temperature tunnel construction can be predicted according to the simulated temperature field.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel construction, and relates to high geothermal tunnel construction technology, and specifically to a method and system for predicting a temperature field in a high geothermal tunnel. Background Art

[0002] The high ground temperature problem in tunnels not only has an unignorable impact on the safety of machinery and personnel during construction, and then affects the construction quality, but also affects the normal use of equipment in the tunnel during operation. Specifically, it is manifested in the following aspects: 1. When spraying concrete on the surface of high-temperature surrounding rock, there may be problems of low bonding strength or difficulty in spraying; 2. When pouring tunnel lining concrete, the mold temperature may be too high, affecting the quality of concrete pouring; 3. The heat of cement hydration is not easy to dissipate, affecting the strength of concrete and endangering the safety of the structure; 4. It affects the tunnel support structures such as anchor rods (cables), concrete spraying layers, and linings, and may even induce failure of the tunnel support structures; 5. It reduces the construction efficiency of construction machinery and affects the labor safety of construction personnel. Therefore, high ground temperature tunnels have many influences during tunnel construction, but in the current research on high ground temperature in tunnels, the temperature field distribution of high ground temperature tunnels cannot be well predicted, resulting in the inability to predict the temperature in high ground temperature tunnels, which causes inconvenience to the construction of high ground temperature tunnels. Summary of the invention

[0003] As described in the above background technology, the prior art is unable to well predict the temperature field distribution in a high geothermal tunnel, resulting in the inability to predict the temperature in the high geothermal tunnel, which causes inconvenience to the construction of the high geothermal tunnel. To address this technical problem, the present invention proposes a method and system for predicting the temperature field in a high geothermal tunnel.

[0004] The present invention combines the actual construction situation of high geothermal tunnels, comprehensively considers the influencing factors that affect the temperature field distribution in high geothermal tunnels, couples the influencing factors such as surrounding rock, underground seepage water and wind flow, and starts from actual engineering. It takes the basic theory of heat transfer and the basic theory of seepage as the theoretical basis to achieve the coupling of surrounding rock, underground seepage water and wind flow, simulates the temperature field distribution in high geothermal tunnels, so as to provide support for the construction of high geothermal tunnels and reduce the harm caused by the high geothermal temperature of the tunnel to mechanical equipment, personnel safety and construction quality during the construction process.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for predicting the temperature field in a high ground temperature tunnel, comprising the following steps:

[0007] S1: Get the initial value of the high ground temperature tunnel;

[0008] S2: Establish the surrounding rock tunnel model;

[0009] S3: setting the surrounding rock tunnel model to be in a non-uniform temperature field, substituting the initial value of the high geothermal tunnel into the surrounding rock tunnel model to initialize the model;

[0010] S4: setting the air flow temperature in the initialization model; using Darcy's law, setting the underground seepage water in the initialization model to form a coupled tunnel model after the surrounding rock, underground seepage water and air flow are coupled;

[0011] S5: Use the coupled tunnel model to predict the temperature field in high geothermal tunnels.

[0012] It is further defined that in step S2, the surrounding rock tunnel model is established using COMSOL software.

[0013] It is further defined that in step S4, setting the air flow temperature in the initialization model specifically includes:

[0014] Establish the governing equations for heat transfer in porous media;

[0015] The air flow temperature is determined using the porous media heat transfer governing equation;

[0016] The wind flow temperature is substituted into the initialization model, thereby setting the wind flow temperature in the initialization model.

[0017] It is further defined that the porous medium heat transfer control equation is:

[0018]

[0019] (ρC p ) eff =∈ p ρ f C p，f +θ s ρ s C p，s

[0020] K eff =∈ p k f +θ s k s

[0021] In the formula, eff is the effective value, dimensionless; ∈ p is the porosity, dimensionless; θ s is the volume fraction of solid in the porous medium, dimensionless; k f k is the thermal conductivity of the fluid, unit: W / (℃·m); s is the thermal conductivity of solid, unit: W / (℃·m); ρ f is the fluid density, unit: kg / m 3 ρ sis the solid density, unit: kg / m 3 ; C p,f is the specific heat capacity of liquid at constant pressure, unit: J / (kg·K); C p,s is the constant pressure specific heat capacity of the solid, unit: J / (kg·K); v is the Darcy seepage velocity, unit: m / s; ρ is the effective density, unit: kg / m 3 ; C p is the effective specific heat capacity, unit: J / (kg·K); T is the object temperature, unit: ℃; t is the time, unit: s; is the fluid seepage temperature gradient, unit: °C / m; is the temperature gradient of the surrounding rock, unit: °C / m; q is the heat flux, unit: W / m 2 ;k eff is the effective thermal conductivity, unit: W / (℃·m).

[0022] It is further defined that in step S4, using Darcy's law, setting the underground seepage water in the initialization model specifically includes:

[0023] The groundwater seepage control equation is established using Darcy's law;

[0024] Set the seepage water flow direction and use the groundwater seepage control equation to determine the changing relationship between the seepage velocity and the seepage pressure;

[0025] The flow direction of seepage water and the changing relationship between seepage velocity and seepage pressure are substituted into the initialization model, so as to set the underground seepage water in the initialization model.

[0026] It is further defined that the groundwater seepage control equation is:

[0027]

[0028] In the formula, ∈ p is the porosity, dimensionless; ρ f is the fluid density, unit: kg / m 3 ; u is the seepage velocity field, unit: m / s; κ is the porous matrix permeability, dimensionless; μ is the fluid dynamic viscosity, unit: Pa·s; is the seepage pressure gradient, unit: N / m; t is the time, unit: s; is the viscous work gradient, unit: kg / (s·m 3 ).

[0029] It is further defined that step S4 further includes: setting irregular cracks in the surrounding rock in the initialization model of the underground seepage water.

[0030] It is further defined that the initial values ​​of the high geothermal tunnel include the tunnel bottom height, the tunnel model height, the tunnel top temperature, the temperature distribution law along the height direction in the tunnel, and the tunnel boundary temperature.

[0031] It is further defined that the temperature distribution law T in the tunnel along the height direction is Z for:

[0032] T Z =(h max -0.05*h)*1℃

[0033] Where, T Z is the temperature distribution law along the height direction in the tunnel, unit: m·℃; h max is the height of the tunnel model, unit: m; h is the change height of the model tunnel, unit: m.

[0034] The present invention provides a system for predicting the temperature field in a high geothermal tunnel, which is applied to the above-mentioned method for predicting the temperature field in a high geothermal tunnel, and comprises:

[0035] Acquisition module: used to obtain the initial value of the high ground temperature tunnel;

[0036] Model building module: used to build surrounding rock tunnel model;

[0037] Initialization module: used to set the surrounding rock tunnel model to be in a non-uniform temperature field, and substitute the initial value of the high geothermal tunnel into the surrounding rock tunnel model to initialize the model;

[0038] Coupling module: used to set the wind flow temperature in the initialization model, and use Darcy's law to set the underground seepage water in the initialization model to form a coupled tunnel model after the surrounding rock, underground seepage water and wind flow are coupled;

[0039] And the prediction module: used to predict the temperature field in the high geothermal tunnel using the coupled tunnel model.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. The present invention provides a method for predicting the temperature field in a high geothermal tunnel. The method combines the actual construction conditions of the high geothermal tunnel, comprehensively considers the influencing factors affecting the temperature field distribution in the high geothermal tunnel, couples the influencing factors such as surrounding rock, underground seepage water and wind flow, and starts from the actual project. The method takes the basic theory of heat transfer and the basic theory of seepage as the theoretical basis to achieve the coupling of the surrounding rock, underground seepage water and wind flow, simulates the temperature field distribution in the high geothermal tunnel, and predicts the potential risks in the construction of the high geothermal tunnel according to the simulated temperature field, provides technical support for the construction of the high geothermal tunnel, and reduces the harm caused by the high geothermal temperature in the tunnel to the mechanical equipment, personnel safety and construction quality during the construction process.

[0042] 2. The present invention provides a method for predicting the temperature field in a high geothermal tunnel. It can also set irregular cracks in the surrounding rock in the initialization model of the underground seepage water, with the purpose of forming a fault fracture zone in the surrounding rock. While coupling the surrounding rock, underground seepage water and wind flow, it fully considers the influence of the fault fracture zone, making the coupled tunnel model more in line with the actual situation of the tunnel. At the same time, the present invention provides a complete operation idea and operation process by setting the fault fracture zone in the surrounding rock, and also provides ideas for comprehensively, completely and reliably simulating the temperature field distribution in the high geothermal tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of a method for predicting temperature field in a high geothermal tunnel according to the present invention;

[0044] Figure 2 It is a schematic diagram of a prediction system for temperature field in a high geothermal tunnel of the present invention;

[0045] Figure 3 This is the non-uniform initial temperature field cloud diagram of the surrounding rock tunnel model;

[0046] Figure 4 This is the convection heat transfer boundary diagram of the initialized model after setting the air flow temperature in the initialized model;

[0047] Figure 5 The seepage water streamline diagram of the initialized model after setting the underground seepage water in the initialized model;

[0048] Figure 6 The cloud diagram of the seepage water velocity field of the initialized model after setting the underground seepage water in the initialized model;

[0049] Figure 7 The seepage water pressure cloud diagram of the initialized model after setting the underground seepage water in the initialized model;

[0050] Figure 8 This is a simulation diagram of setting a fault fracture zone in the surrounding rock. DETAILED DESCRIPTION

[0051] The technical solution of the present invention is further explained below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited to the implementation modes described below.

[0052] At present, the research on the high geothermal problem in the prior art has not taken into account the mutual coupling of underground seepage water, surrounding rock and wind flow, and the temperature field inside the high geothermal tunnel is complex and changeable. The present invention starts from the actual situation of the actual project, takes the basic theory of heat transfer and the basic theory of seepage as the theoretical basis, and based on the COMSO software, realizes the coupling of surrounding rock, underground seepage water and wind flow, forms a fault fracture zone, and simulates the temperature distribution in the high geothermal tunnel, so as to provide a theoretical basis and operational support for the construction of the high geothermal tunnel.

[0053] Example 1

[0054] See also Figure 1 The present embodiment provides a method for predicting the temperature field in a high ground temperature tunnel, which comprises the following steps:

[0055] S1: Obtaining initial values ​​of the high geothermal tunnel; wherein the initial values ​​of the high geothermal tunnel include tunnel bottom height, tunnel model height, tunnel top temperature, temperature distribution law along the height direction in the tunnel, and tunnel boundary temperature; specifically, the temperature distribution law along the height direction in the tunnel is:

[0056] T Z =(h max -0.05*h)*1℃

[0057] Where, T Z is the temperature distribution law along the height direction in the tunnel, unit: m·℃; h max is the height of the tunnel model, unit: m; h is the change height of the model tunnel, unit: m.

[0058] In this embodiment, the height of the tunnel model established is 60m, that is, the temperature distribution law along the height direction in the tunnel corresponding to this embodiment is:

[0059] T Z =(60-0.05*h)*1℃.

[0060] S2: Establish the surrounding rock tunnel model; for details, see Figure 3 The surrounding rock tunnel model is established by using COMSOL software, and the following steps S3, S4 and S5 are also completed in COMSOL software. In addition, the surrounding rock tunnel model is not limited to being established by COMSOL software, and it can also be established by other software that can perform tunnel simulation known to those skilled in the art.

[0061] S3: The surrounding rock tunnel model is set in a non-uniform temperature field, and the initial value of the high geothermal tunnel is substituted into the surrounding rock tunnel model to initialize the model; specifically, in COMSOL software, the tunnel bottom height, tunnel model height, tunnel top temperature, temperature distribution law along the height direction in the tunnel, and tunnel boundary temperature are set for the surrounding rock tunnel model to initialize the surrounding rock tunnel model and establish an initialization model.

[0062] S4: Set the air flow temperature in the initialization model; for details, see Figure 4 , in COMSOL software, establish the porous medium heat transfer control equation; use the porous medium heat transfer control equation to determine the air flow temperature; substitute the air flow temperature into the initialization model, so as to set the air flow temperature in the initialization model. The time scale of temperature change in the temperature field of the surrounding rock in the tunnel is days or months, while the time scale of ventilation temperature change in the tunnel is seconds. Therefore, when studying the temperature field of the surrounding rock in the tunnel, it can be considered that the ventilation in the tunnel has been stable, and the input of the wind flow temperature can be simplified to the setting of boundary conditions. In COMSOL software, the simulation of ventilation is achieved by setting the convection heat transfer boundary. The established porous medium heat transfer control equation is introduced into COMSOL software, that is, a new "heat flux" module is created in the heat transfer module, all surfaces of the inner wall of the tunnel are selected, and the boundary relies on the lining structure. The material type is "solid", the flux type is selected as "convective heat flux", and the heat transfer coefficient is selected as "user defined". The required "heat transfer coefficient" and "external temperature" are set according to the working conditions. Among them, one side of the boundary is the lining, and the other side (i.e., the outside) is the simulated wind flow, and the "external temperature" is the wind flow temperature.

[0063] Using Darcy's law, underground seepage water is set in the initialization model to form a coupled tunnel model after coupling of surrounding rock, underground seepage water and wind flow; specifically, Darcy's law is used to establish the groundwater seepage control equation; the seepage water flow direction is set, and the changing relationship between the seepage velocity and the seepage pressure is determined using the groundwater seepage control equation; the seepage water flow direction and the changing relationship between the seepage velocity and the seepage pressure are substituted into the initialization model, thereby setting the underground seepage water in the initialization model.

[0064] In COMSOL software, Darcy's law module is used to simulate underground seepage water. The initialization model is under standard atmospheric pressure, and the initial value of the seepage water pressure of the initialization model is 0. Underground seepage water will flow due to gravity. Assuming that the seepage water in the initialization model flows from the upper left to the lower right, an "inlet" boundary is applied to the left and upper boundaries of the initialization model, and the "boundary condition" is selected as the "velocity" boundary. The required seepage velocity is set according to the working conditions. An "outlet" boundary is applied to the right and lower boundaries of the initialization model, and the "boundary condition" is set to "pressure". The pressure value is set to 0Pa to simulate the free flow of underground seepage water. See Figure 5 , Figure 6 and Figure 7 , and then the groundwater seepage water is set in the initialization model and the simulation calculation is performed to obtain the following results: Figure 5 The flow line diagram of seepage water, such as Figure 6 The seepage water velocity field cloud diagram and Figure 7 Seepage water pressure cloud diagram.

[0065] S5: The temperature field in the high geothermal tunnel is predicted using the coupled tunnel model. Specifically, the temperature of each point in the tunnel can be simulated and calculated using the coupled tunnel model. Based on the temperature of each point in the tunnel, the temperature field in the high geothermal tunnel is obtained, thereby realizing the prediction of the temperature field in the high geothermal tunnel.

[0066] Among them, step S4 also includes: setting irregular cracks in the surrounding rock in the initialization model of underground seepage water to form a fault fracture zone in the surrounding rock. The difference between the fault fracture zone and the surrounding rock is that there are cracks inside the fault fracture zone and the thermal physical parameters and seepage velocity inside the fault fracture zone are different from those of the surrounding surrounding rocks. Different thermal physical parameters can be achieved by setting different materials to assign values; different seepage velocities can be achieved through different seepage water velocity inlet boundaries. In the COMSOL software, the fault fracture zone has a built-in discrete_fracture_network_3d plug-in, wherein discrete_fracture_network_3d refers to a discrete fracture network in 3D space. This plug-in can realize the random distribution of irregular thin surfaces, so irregular thin surfaces can be used to realize the simulation of fractures inside the fault fracture zone. The random distribution of cracks within the fault fracture zone can be achieved by setting the size, direction, and properties of the thin surface. In this embodiment, the size of the thin surface is: the minimum axis length is 1 meter, the maximum axis length is 5 meters, and the power law index is 2; the direction distribution of the thin surface is Fisher, the inclination angle of the thin surface is 60°, and the diffusion coefficient of the thin surface is 0.1; the porosity is 0.7, the roughness coefficient is 1, and the scale factor is 0.001, forming the following Figure 8 The fault zone shown.

[0067] In this embodiment, the porous medium heat transfer control equation is:

[0068]

[0069] (ρC p ) eff =∈ p ρ f C p，f +θ s ρ s C p，s

[0070] K eff =∈ p k f +θ s k s

[0071] In the formula, eff is the effective value, dimensionless; ∈ p is the porosity, dimensionless; θ s is the volume fraction of solid in the porous medium, dimensionless; k f k is the thermal conductivity of the fluid, unit: W / (℃·m); s is the thermal conductivity of solid, unit: W / (℃·m); ρ f is the fluid density, unit: kg / m 3 ρ s is the solid density, unit: kg / m 3 ; C p,f is the specific heat capacity of liquid at constant pressure, unit: J / (kg·K); C p,s is the constant pressure specific heat capacity of the solid, unit: J / (kg·K); v is the Darcy seepage velocity, unit: m / s; ρ is the effective density, unit: kg / m 3 ; C p is the effective specific heat capacity, unit: J / (kg·K); T is the object temperature, unit: ℃; t is the time, unit: s; is the fluid seepage temperature gradient, unit: °C / m; is the temperature gradient of the surrounding rock, unit: °C / m; q is the heat flux, unit: W / m 2 ;k eff is the effective thermal conductivity, unit: W / (℃·m).

[0072] In this embodiment, the groundwater seepage control equation is:

[0073]

[0074] In the formula, ∈ p is the porosity, dimensionless; ρ f is the fluid density, unit: kg / m 3; u is the seepage velocity field, unit: m / s; κ is the porous matrix permeability, dimensionless; μ is the fluid dynamic viscosity, unit: Pa·s; is the seepage pressure gradient, unit: N / m; t is the time, unit: s; is the viscous work gradient, unit: kg / (s·m 3 ).

[0075] In this embodiment, the tunnel boundary temperature includes the left boundary temperature of the tunnel, the right boundary temperature of the tunnel, the upper boundary temperature of the tunnel, and the lower boundary temperature of the tunnel.

[0076] In this embodiment, the seepage pressure is determined according to the boundary conditions.

[0077] The present embodiment provides a method for predicting the temperature field in a high geothermal tunnel. Starting from actual engineering, the method takes the basic theory of heat transfer and the basic theory of seepage as theoretical foundations, and based on COMSOL software, realizes the coupling of surrounding rock, underground seepage water and wind flow, and simulates the temperature field distribution in the high geothermal tunnel. According to the simulated temperature field, the potential risks in the construction of the high geothermal tunnel can be predicted in advance, and improvement measures can be arranged in advance according to the prediction results, so as to provide technical support for the construction of the high geothermal tunnel, so as to reduce the harm caused by the high geothermal in the tunnel to the mechanical equipment, personnel safety and construction quality during the construction process.

[0078] Example 2

[0079] See also Figure 2 The present embodiment provides a system for predicting the temperature field in a high geothermal tunnel, which is applied to the method for predicting the temperature field in a high geothermal tunnel of Embodiment 1, and includes:

[0080] Acquisition module: used to obtain the initial value of the high ground temperature tunnel;

[0081] Model building module: used to build surrounding rock tunnel model;

[0082] Initialization module: used to set the surrounding rock tunnel model in a non-uniform temperature field, and substitute the initial value of the high ground temperature tunnel into the surrounding rock tunnel model to initialize the model;

[0083] Coupling module: used to set the air flow temperature in the initialization model; using Darcy's law, set the underground seepage water in the initialization model to form a coupled tunnel model after the surrounding rock, underground seepage water and air flow are coupled;

[0084] And the prediction module: used to predict the temperature field in the high geothermal tunnel using the coupled tunnel model.

[0085] The prediction method of the temperature field in the high geothermal tunnel of this embodiment is completely corresponding to the prediction system of the temperature field in the high geothermal tunnel of Example 1. For the specific contents of the acquisition module, model building module, initialization module, coupling module and prediction module, please refer to the description of the prediction method of the temperature field in the high geothermal tunnel in Example 1.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the present invention.

Claims

1. A method for predicting temperature field in a high geothermal tunnel, characterized in that: The following steps are involved: S1: Get the initial value of the high ground temperature tunnel; S2: Establish surrounding rock tunnel model; S3: setting the surrounding rock tunnel model to be in a non-uniform temperature field, substituting the initial value of the high geothermal tunnel into the surrounding rock tunnel model to initialize the model; S4: setting the air flow temperature in the initialization model; using Darcy's law, setting the underground seepage water in the initialization model to form a coupled tunnel model after the surrounding rock, underground seepage water and air flow are coupled; S5: Use the coupled tunnel model to predict the temperature field in high geothermal tunnels.

2. The method for predicting the temperature field in a high geothermal tunnel according to claim 1, characterized in that: In step S2, the surrounding rock tunnel model is established using COMSOL software.

3. The method for predicting the temperature field in a high geothermal tunnel according to claim 1, characterized in that: In step S4, setting the air flow temperature in the initialization model specifically includes: Establish the governing equations for heat transfer in porous media; The air flow temperature is determined using the porous media heat transfer governing equation; The wind flow temperature is substituted into the initialization model, thereby setting the wind flow temperature in the initialization model.

4. The method for predicting the temperature field in a high geothermal tunnel according to claim 3, characterized in that: The porous medium heat transfer control equation is: (ρC p ) eff =∈ p r f C p，f +θ s r s C p，s k eff =∈ p k f +θ s k s In the formula, eff is the effective value, dimensionless; ∈ p is the porosity, dimensionless; θ s is the volume fraction of solid in the porous medium, dimensionless; k f k is the thermal conductivity of the fluid, unit: W / (℃·m); s is the thermal conductivity of solid, unit: W / (℃·m); ρ f is the fluid density, unit: kg / m 3 ; ρ s is the solid density, unit: kg / m 3 ; C p，f is the specific heat capacity of liquid at constant pressure, unit: J / (kg·K); C p，s is the constant pressure specific heat capacity of solid, unit: J / (kg·K); v is the Darcy seepage field velocity, unit: m / s; ρ is the effective density, unit: kg / m 3 ; C p is the effective specific heat capacity, unit: J / (kg·K); T is the object temperature, unit: ℃; t is time, unit: s; is the fluid seepage temperature gradient, unit: °C / m; is the temperature gradient of the surrounding rock, unit: °C / m; q is the heat flux, unit: W / m 2 ;k eff is the effective thermal conductivity, unit: W / (℃·m).

5. The method for predicting the temperature field in a high geothermal tunnel according to claim 3, characterized in that: In step S4, Darcy's law is used to set the underground seepage water in the initialization model, which specifically includes: The groundwater seepage control equation is established using Darcy's law; Set the flow direction of seepage water and use the groundwater seepage control equation to determine the relationship between seepage velocity and seepage pressure; The flow direction of seepage water and the changing relationship between seepage velocity and seepage pressure are substituted into the initialization model, so as to set the underground seepage water in the initialization model.

6. The method for predicting the temperature field in a high ground temperature tunnel according to claim 5, characterized in that: The groundwater seepage control equation is: In the formula, ∈ p is the porosity, dimensionless; ρ f is the fluid density, unit: kg / m 3 ; u is the seepage velocity field, unit: m / s; κ is the porous matrix permeability, dimensionless; μ is the fluid dynamic viscosity, unit: Pa·s; Vp is the seepage pressure gradient, unit: N / m; t is the time, unit: s; is the viscous work gradient, unit: kg / (s·m 3 ).

7. The method for predicting the temperature field in a high geothermal tunnel according to claim 4, characterized in that: The step S4 also includes: setting irregular cracks in the surrounding rock in the initialization model of underground seepage water.

8. The method for predicting the temperature field in a high geothermal tunnel according to claim 1, characterized in that: The initial values ​​of the high geothermal tunnel include the tunnel bottom height, the tunnel model height, the tunnel top temperature, the temperature distribution law along the height direction in the tunnel, and the tunnel boundary temperature.

9. The method for predicting the temperature field in a high geothermal tunnel according to claim 8, characterized in that: The temperature distribution law along the height direction in the tunnel T Z for: T Z =(h max -0.05*h)*1℃ Where, T Z is the temperature distribution law along the height direction in the tunnel, unit: m·℃; h max is the height of the tunnel model, unit: m; h is the change height of the model tunnel, unit: m.

10. A system for predicting temperature field in a high geothermal tunnel, applied to the method for predicting temperature field in a high geothermal tunnel according to claim 1, characterized in that: include: Acquisition module: used to obtain the initial value of the high ground temperature tunnel; Model building module: used to build surrounding rock tunnel model; Initialization module: used to set the surrounding rock tunnel model to be in a non-uniform temperature field, and substitute the initial value of the high geothermal tunnel into the surrounding rock tunnel model to initialize the model; Coupling module: used to set the air flow temperature in the initialization model; Using Darcy's law, underground seepage water is set in the initialization model to form a coupled tunnel model after the surrounding rock, underground seepage water and wind flow are coupled; And the prediction module: used to predict the temperature field in the high geothermal tunnel using the coupled tunnel model.

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