Arch dam temperature load calculation method adopting permanent heat preservation measures in cold region

Abstract

The invention discloses a method for calculating temperature load of an arch dam adopting permanent heat preservation measures in a cold region, which comprises the following steps of: calculating a quasi-stable temperature field of a typical section of the arch dam by adopting a finite element method and combining thermal parameters of heat preservation materials and concrete of upstream and downstream dam surfaces of the arch dam according to a stable heat conduction principle; the calculation of the temperature load of the arch dam adopting the permanent heat preservation measure in the cold region is realized, a new method for calculating the temperature load of the arch dam adopting the heat preservation measure is explored, and the efficiency and the precision of temperature load calculation are improved.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy and hydropower engineering, and is particularly suitable for a temperature load calculation method of an arch dam that adopts permanent thermal insulation measures in cold regions. Background Art

[0002] As one of the main loads of an arch dam, the temperature load is determined by the difference between the concrete temperature of the dam body and the sealing arch temperature during operation. In general, the temperature load of the dam body should be calculated separately for the design temperature rise and the design temperature drop. For arch dams in mild climates, the dam body is in direct contact with reservoir water and air. The temperature load of the arch dam can be directly calculated using the formula recommended in the "Specifications for the Design of Concrete Arch Dams" (SL282-2018). However, for arch dams in cold regions, due to the huge annual temperature fluctuations, permanent insulation measures are usually added to the arch dam body to ensure the safety of temperature control and crack prevention during the construction period and the structural safety during the operation period. After permanent insulation measures are adopted for the arch dam body in cold regions, the external upstream water temperature and downstream air temperature transfer heat through thermal convection with the insulation material, and the insulation material then conducts heat with the dam body. However, compared with concrete, the thermal conductivity and convection coefficients of thermal insulation materials are smaller. Therefore, after thermal insulation materials are used, the temperature load of the arch dam is significantly different from that of the arch dam without thermal insulation materials. The present invention provides a method for calculating the temperature load of the arch dam that has taken permanent thermal insulation measures in cold areas. Summary of the invention

[0003] The present invention aims to provide a method for calculating the temperature load of an arch dam in cold regions which takes permanent thermal insulation measures, so as to solve the problem of calculating the temperature load of an arch dam in cold regions which takes permanent thermal insulation measures.

[0004] To achieve the above object, the present invention adopts the following technical solutions: The method for calculating the temperature load of an arch dam in cold regions with permanent insulation measures according to the present invention comprises the following steps: S1, collect meteorological data and ground temperature data of the dam site to be built, and determine the annual average water surface temperature after the arch dam is built; S2, refer to the measured reservoir bottom water temperature of similar reservoirs that have been built to determine the reservoir bottom water temperature after the arch dam is built; S3, determine the annual average water temperature at any depth of the reservoir, the annual variation of water temperature, the phase difference of water temperature variation, and the dam surface temperature directly in contact with the air temperature above the dam surface water level according to the empirical formula; S4, determining the performance parameters of the thermal insulation materials used in the arch dam to be built; S5, construct the finite element model of the typical section of the arch dam and establish the corresponding unit components and node components; S6, according to the heat conduction theory, input the unit component parameters and node component boundary conditions, and calculate the stable temperature field of the typical section of the arch dam through finite element solution; S7, taking the stable temperature field as the initial condition, modifying the boundary conditions of the node components, and calculating the quasi-stable temperature field of the arch dam typical section in different months through finite element solution; S8. Based on the quasi-stable temperature field of the typical section of the arch dam in different months, the temperature values ​​of the upstream and downstream dam surfaces in the month with the highest monthly average temperature in the dam site area are taken as the difference between the sealing arch temperature at the corresponding elevation to determine the temperature load of the arch dam under the temperature rise condition; the temperature values ​​of the upstream and downstream dam surfaces in the month with the lowest monthly average temperature in the dam site area are taken as the difference between the sealing arch temperature at the corresponding elevation to determine the temperature load of the arch dam under the temperature drop condition.

[0005] Furthermore, the insulation material performance parameters in step S4 include the thickness of the insulation material on the upstream dam surface. , thermal conductivity , surface heat release coefficient , the thickness of the insulation material on the downstream dam surface , thermal conductivity , surface heat release coefficient , Thermal conductivity of dam concrete , surface heat release coefficient , thermal conductivity of the dam foundation rock mass , surface heat release coefficient .

[0006] Furthermore, step S5 specifically includes that the unit components include an upstream thermal insulation material unit component, a downstream thermal insulation material unit component, a dam body unit component, and a dam foundation rock unit component; the node components include a node component where the upstream dam surface thermal insulation material contacts the reservoir water, a node component where the upstream dam surface thermal insulation material contacts the air, a node component where the downstream dam surface thermal insulation material contacts the air, a node component where the dam top contacts the air, and a dam foundation rock node component.

[0007] Furthermore, the unit component parameters in step S6 include assigning the upstream insulation material unit component, the thermal conductivity of the upstream insulation material , surface heat release coefficient ; Assign the thermal conductivity of the downstream insulation material to the unit component of the downstream insulation material , surface heat release coefficient ; Assign the thermal conductivity of the dam body unit components and the dam body concrete , surface heat release coefficient ; Assign the thermal conductivity of the dam foundation rock mass unit component to the dam foundation rock mass , surface heat release coefficient .

[0008] Furthermore, the node component boundary conditions in step S6 include applying the multi-year average water temperature of the corresponding water depth to the node component where the upstream insulation material is in contact with the reservoir water according to the water depth at the node; applying the fixed boundary condition of multi-year average air temperature + solar radiation temperature rise to the node component where the upstream dam surface insulation material is in contact with the air; applying the fixed boundary condition of multi-year average air temperature + solar radiation temperature rise to the node component where the downstream insulation material is in contact with the air; applying the fixed boundary condition of multi-year average air temperature + solar radiation temperature rise to the node component where the dam top is in contact with the air; and applying the multi-year average ground temperature of the dam site to the dam foundation rock node component.

[0009] Furthermore, the node component boundary conditions in step S7 include applying the average water temperature of the corresponding month at the corresponding water depth to the node components where the upstream insulation material contacts the reservoir water; applying the boundary conditions of multi-year average temperature + solar radiation temperature rise to produce transient convection to the node components where the upstream dam surface insulation material contacts the air; applying the boundary conditions of multi-year average temperature + solar radiation temperature rise to produce transient convection to the node components where the downstream insulation material contacts the air; applying the boundary conditions of multi-year average temperature + solar radiation temperature rise to produce transient convection to the node components where the dam top contacts the air. After completing the boundary condition adjustment, the quasi-stable temperature field of the typical section of the arch dam is calculated by finite element solution.

[0010] The advantages of the present invention are that based on the principle of stable heat conduction, the finite element method is adopted, and the thermal parameters of the thermal insulation materials and concrete of the upstream and downstream dam surfaces of the arch dam are combined. By calculating the quasi-stable temperature field of the typical section of the arch dam, the temperature load of the arch dam with permanent insulation measures in cold areas is calculated, a new method for calculating the temperature load of the arch dam with insulation measures is explored, and the efficiency and accuracy of the temperature load application are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The present invention is a flow chart of the method.

[0012] Figure 2 This is a multi-year average water temperature distribution diagram of reservoir water at different depths according to the method of the present invention.

[0013] Figure 3 This is a monthly average water temperature distribution diagram of reservoir water at different depths according to the method of the present invention.

[0014] Figure 4 This is a typical cross-sectional view of Example 2 of the present invention.

[0015] Figure 5 , Figure 6 It is a schematic diagram of the finite element unit component and the node component established in Example 2 of the present invention.

[0016] Figure 7 Schematic diagram of characteristic elevation of the arch dam in Example 2 of the present invention. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Example 1 like Figure 1 As shown, the method for calculating the temperature load of an arch dam in a cold region with permanent insulation measures according to the present invention comprises the following steps: S1, collect meteorological data and ground temperature data of the arch dam site to be built, and determine the annual average water surface temperature T after the arch dam is built. s .

[0019] The meteorological data collected mainly include the average temperature T of each month in the dam site to be built. am and solar radiation The average temperature of each month in the arch dam site area is T ai (i=1~12) can calculate the annual average temperature T of the arch dam site to be built am The specific formula is as follows: Formula (1) The annual average temperature T of the arch dam site to be built am The increase in the annual average water temperature caused by solar radiation , we can calculate the annual average water temperature T of the water surface after the arch dam is built. s The specific formula is as follows: Formula (2) S2, refer to the measured reservoir bottom water temperature of similar reservoirs that have been built to determine the reservoir bottom water temperature T after the arch dam is built b .

[0020] S3, determine the annual average water temperature at any depth of the reservoir according to the empirical formula , Annual variation of water temperature , Phase difference of water temperature change And the dam surface temperature Ta above the dam water level that is in direct contact with the air temperature.

[0021] Generally, the annual average water temperature of a reservoir decreases with water depth. The annual average water temperature at any depth can be determined using an empirical formula: The specific formula is as follows: (Formula 3) (Formula 4) (Formula 5) Among them, c and g are intermediate variables without specific meanings; H is the reservoir depth. y is the current calculated depth.

[0022] The annual variation of water temperature includes the annual variation of water temperature on the reservoir surface A0 and the annual variation of water temperature at any depth of the reservoir A(y), where (Formula 6) (Formula 7) T a7 It is the highest monthly average temperature in the whole year in the area of ​​the arch dam to be built. It is the increase in the annual variation of surface water temperature caused by solar radiation.

[0023] The phase difference ε(y) of reservoir water temperature change is calculated based on a large amount of measured data through data fitting and formula (8), and the unit is month. The details are as follows: (month) (Formula 8) Finally, the dam surface temperature Ta above the water level of the upstream and downstream dam surfaces that is in direct contact with the air temperature is determined according to the formula. The specific formula is as follows: (Formula 9) (Formula 10) (Formula 11) Where: A a The annual variation of the average temperature over many years in the area where the arch dam is to be built; is the lowest monthly average temperature of the whole year in the dam site of the arch dam to be built; τ0 is the initial phase of the monthly temperature change, in months, 6.5 for areas with latitudes higher than 30°, and 6.7 for areas with latitudes lower than or equal to 30°; is the temperature rise of the dam surface caused by solar radiation, and P is the annual temperature variation period, which is generally 12 months.

[0024] S4, determine the performance parameters of the insulation material used in the arch dam to be built. The performance parameters of the insulation material include the thickness of the insulation material on the upstream dam surface. , thermal conductivity , surface heat release coefficient , the thickness of the insulation material on the downstream dam surface , thermal conductivity , surface heat release coefficient , Thermal conductivity of dam concrete , surface heat release coefficient , thermal conductivity of the dam foundation rock mass , surface heat release coefficient .

[0025] S5, construct a finite element model of a typical section of an arch dam. The finite element mesh of the dam body is divided according to the body parameters of the arch dam, and the corresponding unit components and node components are established, including the node component where the upstream dam surface insulation material contacts the reservoir water, the node component where the upstream dam surface insulation material contacts the air, the node component where the downstream dam surface insulation material contacts the air, the node component where the dam top contacts the air, the upstream insulation material unit component, the downstream insulation material unit component, the dam body unit component, the dam foundation rock unit component, and the dam foundation rock node component.

[0026] S6, according to the heat conduction theory, input the unit component parameters and node component boundary conditions, and calculate the stable temperature field of the typical section of the arch dam through finite element solution.

[0027] Specifically: give the upstream insulation material unit component, the thermal conductivity of the upstream insulation material , surface heat release coefficient ; Assign the thermal conductivity of the downstream insulation material to the unit component of the downstream insulation material , surface heat release coefficient ; Assign the thermal conductivity of the dam body unit components and the dam body concrete , surface heat release coefficient ; Assign the thermal conductivity of the dam foundation rock mass unit component to the dam foundation rock mass , surface heat release coefficient .

[0028] The multi-year average water temperature T of the corresponding water depth is applied to the node components where the upstream insulation material contacts the reservoir water according to the water depth at the node. m (y); Apply the multi-year average temperature T to the node components of the upstream dam surface insulation material in contact with the air am +Fixed boundary conditions for solar radiation temperature rise Δc; multi-year average temperature T is applied to the node components where the downstream insulation material contacts the air am + fixed boundary conditions of solar radiation temperature rise Δc; the fixed boundary conditions of multi-year average temperature + solar radiation temperature rise are applied to the node components in contact with the air on the dam top; the fixed boundary conditions of multi-year average ground temperature T of the dam site area are applied to the node components of the dam foundation rock mass e .Right now When calculating the stable temperature field, the boundary conditions are: Node components where the upstream dam surface insulation material contacts the air: (Formula 12) Node components where the upstream insulation material contacts the reservoir water: (Formula 13) Components at the node where the downstream insulation material contacts the air: (Formula 14) Node components where the dam top contacts the air: (Formula 15) Dam foundation rock mass node components: (Formula 16) Then, the stable temperature field of the typical section of the arch dam is calculated through finite element solution.

[0029] S7, taking the stable temperature field as the initial condition, modifying the boundary conditions of the node components, and calculating the quasi-stable temperature field of the typical section of the arch dam in different months through finite element solution.

[0030] In this step, the parameters of the unit components remain unchanged. The average water temperature of the corresponding month at the corresponding water depth is applied to the node components where the upstream dam surface insulation material is in contact with the reservoir water; the boundary conditions of multi-year average air temperature + solar radiation temperature rise to produce transient convection are applied to the node components where the upstream dam surface insulation material is in contact with the air; the boundary conditions of multi-year average air temperature + solar radiation temperature rise to produce transient convection are applied to the node components where the downstream insulation material is in contact with the air; the boundary conditions of multi-year average air temperature + solar radiation temperature rise to produce transient convection are applied to the node components where the dam top is in contact with the air. After completing the boundary condition adjustment, the quasi-stable temperature field of the typical section of the arch dam in different months is calculated through the finite element transient solution. That is When calculating the quasi-stable temperature field, the boundary conditions are: Node components where the upstream dam surface insulation material contacts the air: (Formula 17) Node components of upstream insulation material in contact with reservoir water: (Formula 18) Components at the node where the downstream insulation material contacts the air: (Formula 19) Node components where the dam top contacts the air: (Formula 20) Dam foundation rock mass node components: (Formula 21) Where: τ is the time variable in the calculation, the unit is month.

[0031] S8. Based on the quasi-stable temperature field of the typical section of the arch dam in different months, the temperature values ​​of the upstream and downstream dam surfaces in the month with the highest monthly average temperature in the dam site area are taken as the difference between the sealing arch temperature at the corresponding elevation to determine the temperature load of the arch dam under the temperature rise condition; the temperature values ​​of the upstream and downstream dam surfaces in the month with the lowest monthly average temperature in the dam site area are taken as the difference between the sealing arch temperature at the corresponding elevation to determine the temperature load of the arch dam under the temperature drop condition.

[0032] The calculation formula for temperature load under temperature rise conditions is as follows: (Formula 21) (Formula 22) (Formula 23) (Formula 24) Where: is the temperature load at a certain characteristic elevation i on the upstream dam surface under temperature rise conditions; is the temperature load at a certain characteristic elevation i on the downstream dam surface under the temperature rise condition; is the temperature value corresponding to the characteristic elevation i of the upstream dam surface in the quasi-stable temperature field in July; is the temperature value corresponding to the characteristic elevation i of the downstream dam surface in the quasi-stable temperature field in July; is the arch sealing temperature corresponding to the characteristic elevation i of the arch dam; is the average cross-sectional temperature corresponding to the characteristic elevation i of the arch dam; is the linear temperature difference between the upstream and downstream sections corresponding to the characteristic elevation i of the arch dam; and That is, the temperature load value of the section at characteristic elevation i under temperature rise conditions.

[0033] The calculation formula for temperature load under temperature drop condition is as follows: (Formula 25) (Formula 26) (Formula 27) (Formula 28) Where: is the temperature load at a certain characteristic elevation i of the upstream dam surface under the temperature drop condition; is the temperature load at a certain characteristic elevation i of the downstream dam surface under the temperature drop condition; is the temperature value corresponding to the characteristic elevation i of the upstream dam surface in the quasi-stable temperature field in January; is the temperature value corresponding to the characteristic elevation i of the downstream dam surface in the quasi-stable temperature field in January; is the arch sealing temperature corresponding to the characteristic elevation i of the arch dam; is the average cross-sectional temperature corresponding to the characteristic elevation i of the arch dam; is the linear temperature difference between the upstream and downstream sections corresponding to the characteristic elevation i of the arch dam; and That is, the temperature load value at characteristic elevation i under temperature drop conditions.

[0034] Example 2 In a certain cold region, the arch dam has insulation measures taken on both the upstream and downstream dam surfaces. The temperature load calculation method for the arch dam with permanent insulation measures in cold regions shown in the present invention is used to calculate the temperature load as follows: Step 1: Collect meteorological data of the arch dam site in the cold region, use the cosine function to fit the multi-year monthly average temperature, and get the fitting formula: Step 2: Collect the average ground temperature data of the arch dam site for many years to determine the ground temperature T of the arch dam site in the cold region. e =13.6℃.

[0035] Step 3: Calculate the annual average temperature of the water surface after the reservoir is built based on the multi-year average temperature and solar radiation conditions in the dam site area. , refer to the measured data of the bottom water temperature of existing reservoirs with similar conditions, and determine the average water temperature at the bottom of the reservoir by analogy According to this embodiment, the annual average water temperature of the reservoir surface and the reservoir bottom is as follows: Step 4: Use the formula method to calculate the annual average water temperature of the reservoir water at any depth. The maximum height of the arch dam in this cold region is 100m, and the reservoir depth is H=95m. The specific calculation is as follows: The average water temperature distribution of reservoir water at different depths over the years is shown in Figure 2 Step 5: Calculate the annual variation of reservoir water temperature at different depths and the phase difference of reservoir water temperature change. In this example, the specific calculation is as follows: Step 6: Calculate the annual variation of reservoir water temperature at different depths. The expression is as follows: The average monthly water temperature of reservoir water at different depths is shown in Figure 3 .

[0036] Step 7: Obtain the performance parameters of the insulation material actually used in the arch dam. According to the shape parameters of the arch dam, the arch crown beam section of the arch dam is selected as the typical section. The typical section in this example is as follows: Figure 4 As shown in Figure 2. L represents the thickness of the dam.

[0037] Step 8: According to the geometric dimensions of the typical section of the arch dam and the thickness of the insulation material of the upstream and downstream dam surfaces, the thickness of the rock mass below the dam foundation is selected as 1.0 times the dam height. A geometric model is established, the geometric model is meshed, and corresponding units and node components are established. The model is shown in Figure 5 , Figure 6 As shown. Among them, up_fn1 is the node component where the upstream dam surface insulation material contacts the reservoir water; up_fn2 is the node component where the upstream dam surface insulation material contacts the air; down_fn1 is the node component where the downstream dam surface insulation material contacts the air; dam_tn is the node component where the dam top contacts the air; up_bw_e is the upstream insulation material unit component; down_bw_e is the downstream insulation material unit component; dam_e is the dam body unit component; base_e is the dam foundation rock unit component; base_n is the dam foundation rock node component.

[0038] Step 9: Assign the thermal conductivity of the upstream insulation material unit component up_bw_e to the upstream insulation material , surface heat release coefficient , assign the thermal conductivity of the downstream insulation material to the downstream insulation material unit component down_bw_e , surface heat release coefficient , assign the dam body unit component dam_e the thermal conductivity of the dam body concrete , surface heat release coefficient , assign the thermal conductivity of the dam foundation rock mass unit component base_e to the dam foundation rock mass , surface heat release coefficient .

[0039] The first type of boundary condition is applied to the node component up_fn1 where the upstream insulation material contacts the reservoir water according to the water depth at the node, that is, the multi-year average water temperature at the corresponding water depth is constrained. Fixed boundary conditions: Apply the first type of boundary conditions to the node component up_fn2 where the upstream dam surface insulation material contacts the air, i.e., constrain the multi-year average temperature. + Solar radiation temperature rise Fixed boundary conditions; the first type of boundary conditions are applied to the node component down_fn1 where the downstream insulation material contacts the air, that is, the constraint is the multi-year average temperature + Solar radiation temperature rise Fixed boundary conditions: The first type of boundary conditions are applied to the node component dam_tn where the dam top contacts the air, i.e., the constraint is the multi-year average temperature. + Solar radiation temperature rise Fixed boundary conditions.

[0040] After completing the setting of the above material parameters and boundary conditions, the finite element method can be used to calculate the stable temperature field of the typical section of the arch dam.

[0041] Step 10: After completing the calculation of the stable temperature field of the typical dam section of the arch dam, the calculation results of the stable temperature field are used as the initial conditions. The material parameters of the upstream insulation material, downstream insulation material, dam body concrete and dam foundation rock remain unchanged, and the boundary conditions are adjusted. For the node component up_fn1 where the upstream insulation material contacts the reservoir water, the first type of boundary conditions are applied according to the water depth at different months and nodes, that is, the average water temperature of the corresponding month at the corresponding water depth; for the node component up_fn2 where the upstream dam surface insulation material contacts the air, the second type of boundary conditions are applied, that is, the boundary conditions for transient convection with the multi-year average temperature + solar radiation temperature rise; for the node component down_fn1 where the downstream insulation material contacts the air, the second type of boundary conditions are applied, that is, the boundary conditions for transient convection with the multi-year average temperature + solar radiation temperature rise; for the node component dam_tn where the dam top contacts the air, the second type of boundary conditions are applied, that is, the boundary conditions for transient convection with the multi-year average temperature + solar radiation temperature rise.

[0042] After completing the adjustment and setting of the above boundary conditions, the quasi-stable temperature field calculation of the typical section of the arch dam is carried out with a time step of 1 month and a total calculation time of 100 years.

[0043] Step 11: Based on the calculation results of the quasi-stable temperature field of the arch dam typical section in July of the 100th year, extract the temperature values ​​of each characteristic elevation of the upstream and downstream dam surface of the typical dam section, and subtract the sealing arch temperature of the corresponding elevation from it to obtain the temperature load of each characteristic elevation of the upstream and downstream dam surface under the temperature rise condition. After calculation using formula 23 and formula 24, the temperature load value of the section at each characteristic elevation under the temperature rise condition can be obtained: and Specifically, the characteristic elevation of the arch dam in this example is as follows: Figure 7 In this example, the temperature loads at various characteristic elevations of the arch dam under the temperature rise condition are shown in Table 1.

[0044] Table 1 Temperature rise load of arch dams with insulation measures in cold regions S12: Based on the calculation results of the quasi-stable temperature field of the arch dam typical section in January of the 100th year, extract the temperature values ​​of each characteristic elevation of the upstream and downstream dam surface of the typical dam section, subtract the sealing arch temperature of the corresponding elevation, and then obtain the temperature load of each characteristic elevation of the upstream and downstream dam surface under the temperature drop condition. After calculation using formula 27 and formula 28, the temperature load value of the section at each characteristic elevation under the temperature drop condition can be obtained. and , as shown in Table 2.

[0045] Table 2 Temperature drop load of arch dams with insulation measures in cold regions It should be noted that in the cold northern regions, the air temperature and water temperature are usually the highest in July. Therefore, the temperature load of the arch dam under the temperature rise condition can be obtained by taking the calculation results of the quasi-stable temperature field of the arch dam typical section in July as the benchmark and subtracting the sealing arch temperature at the corresponding position of the arch dam typical section. In the cold northern regions, the air temperature and water temperature are usually the lowest in January. Therefore, the temperature load of the arch dam under the temperature drop condition can be obtained by taking the calculation results of the quasi-stable temperature field of the arch dam typical section in January as the benchmark and subtracting the sealing arch temperature at the corresponding position of the arch dam typical section.

[0046] Finally, the present invention uses the empirical formula method to obtain the upstream reservoir water temperature of the arch dam in cold regions and the air temperature above the upstream dam surface water level and the downstream dam surface based on the collected meteorological and hydrological data. Based on the above boundary conditions, the finite element method is first used to calculate the stable temperature field at the typical section of the arch dam. Subsequently, the quasi-temperature field calculation of the arch dam is carried out with the stable temperature field of the typical section of the arch dam as the initial condition and the interannual varying reservoir water temperature and air temperature as the boundary condition. Based on the principle of stable heat conduction, the present invention uses the finite element method, combined with the thermal parameters of the upstream and downstream dam surface insulation materials and concrete of the arch dam, and calculates the quasi-stable temperature field of the typical section of the arch dam, thereby realizing the calculation of the temperature load of the arch dam that takes permanent insulation measures in cold regions, exploring a new method for calculating the temperature load of the arch dam that takes insulation measures, and improving the efficiency and accuracy of the temperature load calculation.

Claims

1. A method for calculating the temperature load of an arch dam in cold regions with permanent insulation measures, characterized in that: The following steps are involved: S1, collect meteorological data and ground temperature data of the arch dam site to be built, and determine the annual average water surface temperature T after the arch dam is built. s ; S2, refer to the measured reservoir bottom water temperature of similar reservoirs that have been built to determine the reservoir bottom water temperature T after the arch dam is built b ; S3, determine the annual average water temperature at any depth of the reservoir according to the empirical formula , the annual variation of water temperature and the phase difference of water temperature variation, as well as the dam surface temperature above the dam surface water level that is in direct contact with the air temperature; S4, determining the performance parameters of the thermal insulation materials used in the arch dam to be built; S5, construct the finite element model of the typical section of the arch dam and establish the corresponding unit components and node components; S6, according to the heat conduction theory, input the unit component parameters and node component boundary conditions, and calculate the stable temperature field of the typical section of the arch dam through finite element solution; S7, taking the stable temperature field as the initial condition, modifying the boundary conditions of the node components, and calculating the quasi-stable temperature field of the arch dam typical section in different months through finite element solution; S8. Based on the quasi-stable temperature field of the typical section of the arch dam in different months, the temperature values ​​of the upstream and downstream dam surfaces in the month with the highest monthly average temperature in the dam site area are taken as the difference between the sealing arch temperature at the corresponding elevation to determine the temperature load of the arch dam under the temperature rise condition; the temperature values ​​of the upstream and downstream dam surfaces in the month with the lowest monthly average temperature in the dam site area are taken as the difference between the sealing arch temperature at the corresponding elevation to determine the temperature load of the arch dam under the temperature drop condition.

2. The method for calculating temperature load of arch dams in cold regions with permanent insulation measures according to claim 1 is characterized by: The insulation material performance parameters in step S4 include the thickness of the insulation material on the upstream dam surface , thermal conductivity , surface heat release coefficient , the thickness of the insulation material on the downstream dam surface , thermal conductivity , surface heat release coefficient , Thermal conductivity of dam concrete , surface heat release coefficient , thermal conductivity of the dam foundation rock mass , surface heat release coefficient .

3. The method for calculating temperature load of arch dams in cold regions with permanent insulation measures according to claim 1 is characterized by: Step S5 specifically includes that the unit components include an upstream thermal insulation material unit component, a downstream thermal insulation material unit component, a dam body unit component, and a dam foundation rock unit component; the node components include a node component where the upstream dam surface thermal insulation material contacts the reservoir water, a node component where the upstream dam surface thermal insulation material contacts the air, a node component where the downstream dam surface thermal insulation material contacts the air, a node component where the dam top contacts the air, and a dam foundation rock node component.

4. The method for calculating the temperature load of an arch dam in cold regions with permanent insulation measures according to claim 3 is characterized by: The unit component parameters in step S6 include assigning the upstream insulation material unit component, the thermal conductivity of the upstream insulation material , surface heat release coefficient ; Assign the thermal conductivity of the downstream insulation material to the unit component of the downstream insulation material , surface heat release coefficient ; Assign thermal conductivity coefficient of dam body unit components and dam body concrete , surface heat release coefficient ; Assign the thermal conductivity of the dam foundation rock mass unit component to the dam foundation rock mass , surface heat release coefficient.

5. The method for calculating temperature load of arch dams in cold regions with permanent insulation measures according to claim 3 is characterized by: The node component boundary condition in step S6 includes applying the multi-year average water temperature of the corresponding water depth to the node component where the upstream insulation material contacts the reservoir water according to the water depth at the node; Apply fixed boundary conditions of multi-year average temperature + solar radiation temperature rise to the node components where the upstream dam surface insulation material contacts the air; The fixed boundary conditions of multi-year average air temperature + solar radiation temperature rise are applied to the node components where the downstream insulation material is in contact with the air; the fixed boundary conditions of multi-year average air temperature + solar radiation temperature rise are applied to the node components where the dam top is in contact with the air; the multi-year average ground temperature of the dam site area is applied to the node components of the dam foundation rock mass.

6. The method for calculating temperature load of arch dams in cold regions with permanent insulation measures according to claim 3 is characterized by: The node component boundary condition in step S7 includes applying the average water temperature of the corresponding month at the corresponding water depth to the node component where the upstream insulation material contacts the reservoir water; Apply the boundary conditions of multi-year average temperature + solar radiation temperature rise to the node components where the upstream dam surface insulation material contacts the air to generate transient convection; The boundary conditions of transient convection generated by multi-year average temperature + solar radiation temperature rise are applied to the node components where the downstream insulation material is in contact with the air; the boundary conditions of transient convection generated by multi-year average temperature + solar radiation temperature rise are applied to the node components where the dam top is in contact with the air; after completing the boundary condition adjustment, the quasi-stable temperature field of the typical section of the arch dam is calculated through finite element solution.

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