Temperature control index optimization method for whole water cooling process of concrete dam

Abstract

The invention provides a temperature control index optimization method for the whole water cooling process of a concrete dam. The method comprises the following steps: firstly, determining concrete temperature allowed by the whole water cooling process of the concrete dam; determining temperature control measure variables and upper and lower limit values of the variables of the whole process optimization of water passing of the concrete dam; establishing a concrete temperature calculation model in the whole water passing process of the concrete dam; establishing a time calculation model for reaching the highest temperature of the concrete heating period / the target temperature of the concrete cooling period; a concrete dam water passing whole process temperature control cost function is established; a concrete temperature calculation model of the whole water passing process of the concrete dam is established according to the determined concrete highest temperature allowed in the temperature rising period of the whole water passing process of the concrete dam, the determined concrete target temperature in the temperature reducing period, temperature control measure optimization variables of the whole water passing process of the concrete dam and upper and lower limit values of the variables; and optimizing the temperature control measure variables of the whole water passing process of the concrete dam according to the time calculation model for the concrete to reach the target temperature and the temperature control cost function of the whole water passing process of the concrete dam.

Description

Technical Field

[0001] The invention relates to a method for optimizing temperature control measures, and in particular to a method for optimizing temperature control indicators during the entire process of water cooling of a concrete dam. Background Art

[0002] After the concrete dam is poured, a large amount of hydration heat will be released during its hardening process. If the temperature control measures are not appropriate, it may cause quality problems such as temperature cracks, insufficient strength, and internal defects in the dam body, which will affect the stability and life of the overall structure. Therefore, temperature control measures, namely water flow measures, are usually taken after the concrete is poured to control the temperature of the concrete. Traditional temperature control measures for concrete dams are usually designed based on experience or test data. The temperature control measures are overly conservative and do not take into account the temperature control costs, which are high.

[0003] In addition, traditional temperature control methods are often limited to adjusting a single factor or making rough estimates in terms of optimizing temperature control measures. They lack a systematic optimization method and fail to find the best balance between comprehensive consideration of temperature control effect and temperature control cost. In particular, traditional water flow temperature control measures tend to be overly conservative temperature control strategies, resulting in waste of resources or excessive costs. With the increase in engineering complexity and changes in environmental conditions, the disadvantages of traditional concrete dam temperature control methods have become more apparent. Summary of the invention

[0004] In view of the above reasons, the purpose of the present invention is to provide a method for optimizing temperature control indicators during the whole process of water cooling of concrete dams. The method comprehensively considers the key variables in the process of concrete heating and cooling, establishes a temperature calculation model for the process of water cooling of concrete dams, and optimizes the variables of temperature control measures during the whole process of water cooling of concrete dams in combination with a cost optimization model.

[0005] To achieve the above object, the present invention adopts the following technical scheme: a method for optimizing temperature control indexes during the whole process of water cooling of a concrete dam, which comprises:

[0006] S1. Determine the permissible concrete temperature during the entire process of water flow through the concrete dam;

[0007] S2. Determine the variables of temperature control measures and the upper and lower limits of the variables for optimizing the whole process of water flow in the concrete dam;

[0008] S3. Establish a concrete temperature calculation model for the entire process of water flow through the concrete dam;

[0009] S4. Establish a time calculation model to reach the maximum temperature of the concrete heating period / target temperature of the cooling period

[0010] S5. Establish the temperature control cost function of the whole process of concrete dam water flow;

[0011] According to the relationship between water temperature, flow rate, water pipe length, water flow time and the unit price of concrete water flow process, the temperature control cost function P3 of the whole process of concrete water flow is established:

[0012]

[0013] In the formula, p w The unit price for cooling 1℃ per kg of water; q w is the flow rate of cooling water pipe; T w T is the water temperature; wt is the cooling water temperature used during water supply; ρ w is the density of water; t is the duration of water flow, d t is the total amount of water-cooled concrete in a casting bin; p t The labor cost for laying each meter of cooling water pipe, excluding the material and machinery cost of cooling water pipe; b. t is the unit price of cooling water pipe; L is the total length of cooling water pipe required for each warehouse of concrete;

[0014] S6. Optimize the variables of temperature control measures during the whole process of water flow in concrete dam;

[0015] S6.1 Optimize the variables of temperature control measures during the concrete heating period;

[0016] S6.1.1 Divide the water temperature interval n during the concrete heating period into equal parts to obtain the water temperature T used for calculation wi , divide the water flow interval n into equal parts, and obtain the flow q used for calculation wi , divide the water pipe spacing into the required interval n, and obtain the horizontal spacing S used in the calculation 1i and longitudinal spacing S 2i ,

[0017] S6.1.2 The flow rate q calculated in step S6.1.1 is wi , water temperature T wi And the horizontal distance S of the water pipe 1i , longitudinal spacing S 2i Perform permutations and combinations, substitute all permutation and combination data into the calculation formula for reaching the maximum temperature time during the heating period established in step S4, and combine the maximum allowable concrete temperature [T max ], calculate the time when the concrete reaches the highest temperature under each combination of variables, and then substitute the time when the concrete reaches the highest temperature calculated by each combination into the temperature calculation model of the concrete water flow process S3 to calculate the temperature T1 of the concrete after water flow;

[0018] S6.1.3 When the calculated concrete temperature T1 after the variables are combined is less than or equal to the maximum allowable concrete temperature T max Greater than the allowable temperature T of the concrete heating process c1When (allowable temperature T c1 <Maximum temperature T max ), retain the flow, water temperature and water pipe spacing values ​​of this group of variable combinations; when the concrete temperature T1 calculated after the variable combination is greater than the maximum allowable concrete temperature T max Or less than the allowable temperature T of the concrete heating process c1 When , the variable combination is discarded;

[0019] S6.1.4 adopts the conversion formula between water pipe spacing and water pipe length in S2.1.2 to convert the water pipe spacing that meets the requirements in S6.1.3 into water pipe length. According to the temperature control cost function of the whole process of water supply of concrete dam established in step S5, calculate the temperature control cost of all variable combinations that meet the maximum temperature of concrete in step S6.1.3, and select the variable combination with the smallest temperature control cost as the optimized variable of temperature control measure during concrete heating period;

[0020] S6.2 Optimize the variables of temperature control measures during the concrete cooling period;

[0021] S6.2.1 Divide the water temperature interval n during the concrete cooling period into equal parts to obtain the water temperature T used for calculation wi , divide the water flow interval n into equal parts, and obtain the flow rate q used in the calculation wi ;

[0022] S6.2.2 The cooling period water temperature T calculated in step S6.2.1 is wi , flow rate q during cooling period wi Perform permutations and combinations, substitute all permutation and combination data and the optimal water pipe spacing calculated in S6.1.4 into the time calculation formula for reaching the target temperature of the concrete cooling period established in step S4, and combine the target temperature T of the concrete cooling period determined in step S1. M , calculate the time for the concrete to reach the target temperature under each optimization combination, and then substitute the calculated optimization combination and target temperature time into the temperature calculation model of the concrete water flow process established in S3 to calculate the concrete temperature T2 after water flow;

[0023] S6.2.3 When the calculated concrete temperature T2 after variable combination is less than or equal to the target temperature T of the concrete cooling period M , greater than or equal to the allowable temperature T of concrete during cooling period c2 When the flow rate, water temperature and water pipe spacing values ​​of the variable combination are retained; when the concrete temperature T2 calculated after the variable combination is greater than the target temperature T of the concrete cooling period M Or less than the allowable temperature T during cooling process c2 , then discard the variable combination;

[0024] S6.2.4 Calculate the temperature control costs of all variable combinations that meet the target temperature of the concrete cooling period in step S6.2.3 based on the temperature control cost function relationship of the cooling process in step S5, and select the variable combination with the smallest temperature control cost as the temperature control measure variable after optimization of the concrete cooling period.

[0025] Preferably, the concrete temperature calculation model for the whole process of water flow through the concrete dam established in step S3 is:

[0026] T c =T w +(T1-T w )φ(t)+θ0ψ(t)

[0027]

[0028] p=kga / 1.362S1S2

[0029] k=2.09-1.35ξ+0.32ξ 2

[0030]

[0031] Where, T c T is the concrete temperature during the whole process of water supply to the concrete dam; w is the water temperature during the water flow process; T1 is the concrete pouring temperature; φ(t) is the water cooling function; θ0 is the final adiabatic temperature rise of concrete; ψ(t) is the adiabatic temperature rise function of concrete; p is the cooling coefficient of the water pipe; t is the water flow time; m is the adiabatic temperature rise coefficient of concrete, which is determined according to the engineering concrete experiment; k is the comprehensive water cooling coefficient; a is the thermal conductivity of concrete; S1 is the horizontal spacing of water pipes, S2 is the longitudinal spacing of water pipes; λ is the thermal conductivity of concrete; L is the length of the water pipe; c w is the specific heat of water in the water supply measure; ρ w is the density of water in the water supply measure; q w For water flow.

[0032] Preferably, the step S4 establishes a time calculation model for reaching the maximum temperature of the concrete heating period / the target temperature of the cooling period as follows:

[0033]

[0034] Where, T max / M T is the maximum temperature of concrete during the heating period or the target temperature of concrete during the cooling period; w is the water temperature; T1 is the concrete pouring temperature; p is the water pipe cooling coefficient.

[0035] Preferably, the temperature control measure variables to be optimized in the whole process of water supply to the concrete dam in step S2 include temperature control measure variables in the concrete heating period and temperature control measure variables in the concrete cooling period;

[0036] The temperature control measure variables during the concrete heating period include water temperature, flow rate and water pipe spacing;

[0037] The temperature control measure variables during the concrete cooling period include water temperature and flow rate;

[0038] The upper limit of water temperature during the concrete heating period is T w-max It is the natural temperature of the cooling water during water cooling;

[0039] The lower limit of water temperature during the concrete heating period is T w·min for:

[0040]

[0041] T w·min =T w·max -Δt w

[0042] Where: Δt w is the maximum temperature drop of cooling water; Q w is the rated cooling capacity of the cooling water system; c w is the specific heat capacity of water; m w T is the mass of cooling water required per hour; w·min T is the lower limit of water temperature during water cooling; w·max is the upper limit of water temperature during water cooling, k is the loss coefficient, which is 1.1 to 1.2;

[0043] For the convenience of calculation, the upper and lower limits of the spacing between water pipes during the concrete heating period are reflected by the upper and lower limits of the total length of water pipes required in a casting bin; the upper limit of the total length of water pipes required in a casting bin L max for:

[0044]

[0045] Where, L max The maximum length of water pipe required to control the temperature of concrete in a pouring bin; is the minimum horizontal spacing of water pipes; The minimum longitudinal spacing of water pipes; d t is the total amount of concrete in a pouring bin;

[0046] The lower limit of the total length of water pipes required in a casting bin is L min for:

[0047]

[0048] Where, L min The minimum length of water pipe required to control the temperature of concrete in a pouring bin; is the maximum horizontal spacing of water pipes; is the maximum longitudinal spacing of the water pipes; d t is the total amount of concrete in a pouring bin;

[0049] The upper limit of water flow rate during concrete heating period q w·max and the lower limit q w·min Determined according to the technical standards for temperature control during the concrete heating period;

[0050] The upper limit value of water temperature during the concrete cooling period is T w·max and the lower limit T w·min , flow upper limit value q w·max and the lower limit q w·min All of them are determined according to the technical standards for temperature control during the concrete cooling period.

[0051] Preferably, during the concrete heating period, the temperature difference between the concrete temperature and the cooling water at the water inlet should not exceed 20°C;

[0052] |T c -T w |≤20

[0053] Where, T c is the average temperature of concrete during the water flow process, T w It is the temperature of water in water cooling.

[0054] Preferably, during the concrete cooling period, the temperature difference between the concrete temperature and the cooling water should not exceed 15°C, that is:

[0055] |T w -T c |≤15

[0056] Where, T c is the average temperature of concrete during the water flow process of the concrete dam, T w The temperature of the water in the water cooling system;

[0057] During the concrete cooling period, the water flow rate should not exceed 1.2m 3 / h is appropriate, that is:

[0058] 0<q w ≤1.2

[0059] In the formula, q w It is the water flow rate during the cooling period. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1This is a flow chart of the method for optimizing temperature control indexes during the whole process of water cooling of a concrete dam according to the present invention;

[0061] Figure 2 This is a flow chart of the method for optimizing temperature control measure variables of the present invention. DETAILED DESCRIPTION

[0062] The structure and features of the present invention are described in detail below in conjunction with the accompanying drawings and embodiments. It should be noted that various modifications can be made to the embodiments disclosed herein, and therefore, the embodiments disclosed in the specification should not be regarded as limiting the present invention, but are merely examples of embodiments, the purpose of which is to make the features of the present invention obvious.

[0063] like Figure 1 As shown, the method for optimizing the temperature control index of the whole process of water cooling of concrete dam in the present invention is:

[0064] S1. Determine the permissible concrete temperature during the entire process of water flow through the concrete dam.

[0065] According to the temperature requirements for the concrete water flow process in the temperature control technical requirements, the maximum concrete temperature allowed during the whole temperature rise period of the concrete dam water flow process [T max ], the allowable concrete temperature T during the heating period c1 and the concrete target temperature T during the cooling period M , the allowable concrete temperature T during the cooling period c2 .

[0066] S2. Determine the variables of temperature control measures for optimization of the entire process of water flow in the concrete dam and the upper and lower limits of the variables.

[0067] During the solidification and hardening process of concrete, its temperature history is divided into a heating period and a cooling period. Therefore, the water flow temperature control for concrete dams is divided into heating period temperature control and cooling period temperature control. During the heating period of concrete, the temperature control measure variables mainly include water flow temperature, flow rate and water pipe spacing (for the convenience of subsequent calculation, the spacing and length are converted); during the cooling period of concrete, the temperature control measure variables mainly include water flow temperature and flow rate.

[0068] S2.1. Determine the variables of temperature control measures during the concrete heating period and the upper and lower limits of the variables.

[0069] During the concrete heating period, the temperature control variables include water temperature, flow rate and water pipe spacing.

[0070] S2.1.1. Determine the upper limit value of water temperature during the concrete heating period T w·max and the lower limit T w·min .

[0071] According to the configuration of the cooling water system during the water supply process at the project site, the upper limit value of the water temperature during the concrete heating period T is determined.w·max and the lower limit T w·min . Upper limit of water temperature T w·max It is the natural temperature of the cooling water during water cooling.

[0072] Determine the rated cooling capacity Q of the cooling water system according to its configuration w , determine the mass of cooling water required per hour based on the maximum flow of concrete w , calculate the maximum cooling amplitude Δt of the cooling water w , thus determining the lower limit of water temperature T w·min , the specific calculation formula is as follows:

[0073]

[0074] T w·min =T w·max -Δt w

[0075] Where: Δt w is the maximum temperature drop of cooling water; Q w is the rated cooling capacity of the cooling water system; c w is the specific heat capacity of water; m w T is the mass of cooling water required per hour; w·min T is the lower limit of water temperature during water cooling; w·max is the upper limit of water temperature during water cooling, k is the loss coefficient, which is taken as 1.1~1.2.

[0076] In particular, according to the relevant specifications for concrete dam projects, the temperature difference between the concrete temperature and the cooling water at the water inlet should not exceed 20°C during the concrete heating period; i.e.

[0077] |T c -T w |≤20

[0078] Where, T c is the average temperature of concrete during the water flow process, T w It is the temperature of water in water cooling.

[0079] S2.1.2. Determine the upper and lower limits of the spacing between water pipes during the concrete temperature rise period.

[0080] The arrangement of the water pipes includes a transverse spacing S1 and a longitudinal spacing S2. According to the arrangement of the transverse and longitudinal spacing of the water pipes, the cooling range A1 of a single water pipe with a length of l is

[0081] A1=S1×S2×l

[0082] In the formula, A1 is the cooling range of a single water pipe; S1 is the horizontal spacing of the water pipes; S2 is the longitudinal spacing of the water pipes; l is the length of a single water pipe.

[0083] The total length L of the water pipe required for a concrete pouring bin is:

[0084]

[0085] Where, d t is the total amount of concrete in a casting bin; S1 is the horizontal spacing of water pipes; S2 is the longitudinal spacing of water pipes.

[0086] The upper limit of the total length of water pipes required in a casting bin is L max The calculation method is:

[0087]

[0088] Where, L max The maximum length of water pipe required to control the temperature of concrete in a pouring bin; is the minimum horizontal spacing of water pipes; The minimum longitudinal spacing of water pipes; d t is the total amount of concrete in a pouring bin;

[0089] The lower limit of the total length of water pipes required in a casting bin is L min The calculation method is:

[0090]

[0091] Where, L min The minimum length of water pipe required to control the temperature of concrete in a pouring bin; is the maximum horizontal spacing of water pipes; is the maximum longitudinal spacing of the water pipes; d t The total amount of concrete in a casting bin.

[0092] Through the above formula, the upper and lower limits of the water pipe spacing are converted into the upper limit of the water pipe length L max and the lower limit L min S2.1.3. Determine the upper limit of water flow rate during concrete heating period q w·max and the lower limit q w·min .

[0093] The upper and lower limits of water flow rate during the water flow and temperature control stage of concrete are given according to the temperature control technical requirements.

[0094] S2.2. Determine the variables of temperature control measures during the concrete cooling period and the upper and lower limits of the variables.

[0095] During the concrete cooling period, the temperature control variables are mainly the water temperature and flow rate.

[0096] According to the requirements of the temperature control standard for concrete cooling period on water temperature and flow rate, determine the upper limit value of water temperature during cooling period T w·max and the lower limit T w·min , flow upper limit value q w·max and the lower limit q w·min .

[0097] In particular, according to the requirements of the relevant specifications for concrete dams, the temperature of the cooling water during the cooling period should not exceed 15°C, that is:

[0098] |T w -T c |≤15

[0099] Where, T c is the average temperature of concrete during the water flow process of the concrete dam, T w The temperature of the water in the water cooling

[0100] According to the specification, the flow rate of concrete during the water cooling period is generally not more than 1.2m 3 / h is appropriate, that is:

[0101] 0<q w ≤1.2

[0102] In the formula, q w It is the water flow rate during the cooling period.

[0103] S3. Establish a concrete temperature calculation model for the entire process of water flow in the concrete dam.

[0104] According to the water temperature, flow rate and water pipe spacing in the temperature control measures of the whole process of water supply to the concrete dam, a concrete temperature calculation model for the whole process of water supply to the concrete dam is established:

[0105] T c =T w +(T1-T w )φ(t)+θ0ψ(t)

[0106]

[0107] p=kga / 1.362S1S2

[0108] k=2.09-1.35ξ+0.32ξ 2

[0109]

[0110] Where, T c T is the concrete temperature during the whole process of water supply to the concrete dam; wis the water temperature during the water flow process; T1 is the concrete pouring temperature; φ(t) is the water cooling function; θ0 is the final adiabatic temperature rise of concrete; ψ(t) is the adiabatic temperature rise function of concrete; p is the cooling coefficient of the water pipe; t is the water flow time; m is the adiabatic temperature rise coefficient of concrete, which is determined according to the engineering concrete experiment; k is the comprehensive water cooling coefficient; a is the thermal conductivity of concrete; S1 is the horizontal spacing of water pipes, S2 is the longitudinal spacing of water pipes; λ is the thermal conductivity of concrete; L is the length of water pipes; c is the thermal conductivity of concrete; w is the specific heat of water in the water supply measure; ρ w is the density of water in the water supply measure; q w For water flow.

[0111] S4. Establish a time calculation model to reach the maximum temperature of the concrete heating period / target temperature of the cooling period

[0112] According to the water pipe spacing, water temperature and flow rate, determine the time t for the concrete to reach the highest temperature / target temperature during the water flow process:

[0113]

[0114] Where, T max / M T is the maximum temperature of concrete during the heating period or the target temperature of concrete during the cooling period; w is the water temperature; T1 is the concrete pouring temperature; p is the water pipe cooling coefficient.

[0115] S5. Establish a temperature control cost function for the entire process of water flow through the concrete dam.

[0116] According to the relationship between water temperature, flow rate, water pipe length, water flow time and the unit price of concrete water flow process, the temperature control cost function P3 of the whole process of concrete water flow is established:

[0117]

[0118] In the formula, p w The unit price for cooling 1℃ per kg of water; q w is the flow rate of cooling water pipe; T w T is the water temperature; wt is the cooling water temperature used during water supply; ρ w is the density of water; t is the duration of water flow, d t is the total amount of water-cooled concrete in a casting bin; p t The labor, material (excluding cooling water pipes) and machinery costs required for laying each meter of cooling water pipe; b t is the unit price of cooling water pipe; L is the total length of cooling water pipe required for each warehouse of concrete.

[0119] S6. Optimize the variables of temperature control measures during the entire process of water flow through the concrete dam.

[0120] According to the maximum concrete temperature allowed in the heating period and the target concrete temperature in the cooling period during the whole process of water flow through the concrete dam determined in step S1, the optimized variables and the upper and lower limits of the temperature control measures during the whole process of water flow through the concrete dam determined in step S2, the concrete temperature calculation model during the whole process of water flow through the concrete dam established in step S3, the time calculation model for the concrete to reach the target temperature established in step S4, and the temperature control cost function during the whole process of water flow through the concrete dam established in step S5, the variables of the temperature control measures during the whole process of water flow through the concrete dam are optimized.

[0121] like Figure 2 As shown in the figure, the specific optimization process is:

[0122] S6.1 Optimize the variables of temperature control measures during the concrete heating period.

[0123] S6.1.1 Divide the water temperature interval n during the concrete heating period into equal parts to obtain the water temperature T used for calculation wi , divide the water flow interval n into equal parts, and obtain the flow q used for calculation wi , divide the water pipe spacing into the required interval n, and obtain the horizontal spacing S used in the calculation 1i and longitudinal spacing S 2i ,

[0124] S6.1.2 The flow rate q calculated in step S6.1.1 is wi , water temperature T wi And the horizontal distance S of the water pipe 1i , longitudinal spacing S 2i Perform permutations and combinations, substitute all permutation and combination data into the time calculation formula for reaching the maximum temperature of concrete during the heating period established in step S4, and combine the maximum allowable concrete temperature [T max ], calculate the time when the concrete reaches the highest temperature under each combination of variables, and then substitute the time when the concrete reaches the highest temperature calculated by each combination into the temperature calculation model of the concrete water flow process S3 to calculate the temperature T1 of the concrete after water flow;

[0125] S6.1.3 When the calculated concrete temperature T1 after the variables are combined is less than or equal to the maximum allowable concrete temperature T max Greater than the allowable temperature T of the concrete heating process c1 When (allowable temperature T c1 <Maximum temperature T max ), retain the flow, water temperature and water pipe spacing values ​​of this group of variable combinations; when the concrete temperature T1 calculated after the variable combination is greater than the maximum allowable concrete temperature T max Or less than the allowable temperature T of the concrete heating process c1 When , the variable combination is discarded;

[0126] S6.1.4 uses the conversion formula between water pipe spacing and water pipe length in S2.1.2 to convert the water pipe spacing that meets the requirements in S6.1.3 into water pipe length. According to the temperature control cost function of the entire process of water flow through the concrete dam established in step S5, calculate the temperature control cost of all variable combinations that meet the maximum temperature of concrete in step S6.1.3, and select the variable combination with the smallest temperature control cost as the optimized variable for temperature control measures during the concrete heating period.

[0127] S6.2 Optimize the variables of temperature control measures during the concrete cooling period.

[0128] S6.2.1 Divide the water temperature interval n during the concrete cooling period into equal parts to obtain the water temperature T used for calculation wi , divide the water flow interval n into equal parts, and obtain the flow rate q used in the calculation wi ;

[0129] S6.2.2 The cooling period water temperature T calculated in step S6.2.1 is wi , flow rate q during cooling period wi Perform permutations and combinations, substitute all permutation and combination data and the optimal water pipe spacing calculated in S6.1.4 into the time calculation formula for reaching the target temperature of the concrete cooling period established in step S4, and combine the target temperature T of the concrete cooling period determined in step S1. M , calculate the time for the concrete to reach the target temperature under each optimization combination, and then substitute the calculated optimization combination and target temperature time into the temperature calculation model of the concrete water flow process established in S3 to calculate the concrete temperature T2 after water flow;

[0130] S6.2.3 When the calculated concrete temperature T2 after variable combination is less than or equal to the target temperature T of the concrete cooling period M , greater than or equal to the allowable temperature T of concrete during cooling period c2 When the flow rate, water temperature and water pipe spacing values ​​of the variable combination are retained; when the concrete temperature T2 calculated after the variable combination is greater than the target temperature T of the concrete cooling period M Or less than the allowable temperature T during cooling process c2 , then discard the variable combination;

[0131] S6.2.4 Calculate the temperature control costs of all variable combinations that meet the target temperature of the concrete cooling period in step S6.2.3 based on the temperature control cost function relationship of the cooling process in step S5, and select the variable combination with the smallest temperature control cost as the temperature control measure variable after optimization of the concrete cooling period.

[0132] Compared with the traditional temperature control method of the whole process of water flow in concrete dam, the present invention has the following innovations:

[0133] 1. The temperature control measures for the whole process of water flow in the concrete dam of the present invention comprehensively consider the three key variables of water temperature, flow rate and water pipe spacing, and determine the upper and lower limits of these variables through scientific methods. Compared with the prior art, the present invention provides a more systematic temperature control optimization method to ensure the accuracy and effect of temperature control. 2. By establishing a temperature calculation model and a temperature control cost model, the present invention can accurately predict and control the temperature change of concrete during the water flow process, especially during the concrete heating and cooling periods. The present invention can effectively avoid problems such as excessive temperature gradient and concrete cracking, and improve the quality and structural stability of the concrete dam. 3. The optimization model of the present invention achieves the best allocation of resources by accurately calculating the temperature control cost, thereby significantly improving the effect of temperature control measures while reducing the temperature control cost. Compared with traditional methods, the present invention can effectively reduce the waste of water, energy and equipment, and reduce the cost of temperature control. 4. The present invention is suitable for various engineering environments and conditions. Whether it is large-volume concrete pouring or the construction of complex structures, it can provide an effective temperature control solution and has a wide range of applicability.

[0134] In summary, the present invention provides an efficient, economical and engineering-compliant temperature control solution by scientifically optimizing the key variables in the concrete temperature control process, which significantly improves the temperature control effect during concrete pouring and curing.

[0135] Finally, it should be noted that the above-described 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, those 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 embodiments of the present invention.

Claims

1. A method for optimizing temperature control indexes during the whole process of water cooling of a concrete dam, characterized in that: It includes the following: S1. Determine the permissible concrete temperature during the entire process of water flow through the concrete dam; S2. Determine the variables of temperature control measures and the upper and lower limits of the variables for optimizing the whole process of water flow in the concrete dam; S3. Establish a concrete temperature calculation model for the entire process of water flow through the concrete dam; S4. Establish a time calculation model to reach the maximum temperature of the concrete heating period / target temperature of the cooling period S5. Establish the temperature control cost function of the whole process of water flow in the concrete dam; According to the relationship between water temperature, flow rate, water pipe length, water flow time and the unit price of concrete water flow process, the temperature control cost function P3 of the whole process of concrete water flow is established: In the formula, p w The unit price for cooling 1℃ per kg of water; q w is the flow rate of cooling water pipe; T w T is the water temperature; wt is the cooling water temperature used during water supply; ρ w is the density of water; t is the duration of water flow, d t is the total amount of water-cooled concrete in a casting bin; p t The labor cost for laying each meter of cooling water pipe, excluding the material and machinery cost of cooling water pipe; b. t is the unit price of cooling water pipe; L is the total length of cooling water pipe required for each warehouse of concrete; S6. Optimize the variables of temperature control measures during the whole process of water flow in concrete dam; S6.1 Optimize the variables of temperature control measures during the concrete heating period; S6.1.1 Divide the water temperature interval n during the concrete heating period into equal parts to obtain the water temperature T used for calculation wi , divide the water flow interval n into equal parts, and obtain the flow q used for calculation wi , divide the water pipe spacing into the required interval n, and obtain the horizontal spacing S used in the calculation 1i and longitudinal spacing S 2i , S6.1.2 The flow rate q calculated in step S6.1.1 is wi , water temperature T wi And the horizontal distance S of the water pipe 1i , longitudinal spacing S 2i Perform permutations and combinations, substitute all permutation and combination data into the calculation formula for reaching the maximum temperature time during the heating period established in step S4, and combine the maximum allowable concrete temperature [T max ], calculate the time when the concrete reaches the highest temperature under each combination of variables, and then substitute the time when the concrete reaches the highest temperature calculated by each combination into the temperature calculation model of the concrete water flow process S3 to calculate the temperature T1 of the concrete after water flow; S6.1.3 When the calculated concrete temperature T1 after the variables are combined is less than or equal to the maximum allowable concrete temperature T max Greater than the allowable temperature T of the concrete heating process c1 When , the flow rate, water temperature and water pipe spacing values ​​of this group of variable combinations are retained; When the calculated concrete temperature T1 after the variables are combined is greater than the maximum allowable concrete temperature T max Or less than the allowable temperature T of the concrete heating process c1 When , the variable combination is discarded; S6.1.4 adopts the conversion formula between water pipe spacing and water pipe length in S2.1.2 to convert the water pipe spacing that meets the requirements in S6.1.3 into water pipe length. According to the temperature control cost function of the whole process of water supply of concrete dam established in step S5, calculate the temperature control cost of all variable combinations that meet the maximum temperature of concrete in step S6.1.3, and select the variable combination with the smallest temperature control cost as the optimized variable of temperature control measure during concrete heating period; S6.2 Optimize the variables of temperature control measures during the concrete cooling period; S6.2.1 Divide the water temperature interval n during the concrete cooling period into equal parts to obtain the water temperature T used for calculation wi , divide the water flow interval n into equal parts, and obtain the flow rate q used in the calculation wi ; S6.2.2 The cooling period water temperature T calculated in step S6.2.1 is wi , flow rate q during cooling period wi Perform permutations and combinations, substitute all permutation and combination data and the optimal water pipe spacing calculated in S6.1.4 into the time calculation formula for reaching the target temperature of the concrete cooling period established in step S4, and combine the target temperature T of the concrete cooling period determined in step S1. M , calculate the time for the concrete to reach the target temperature under each optimization combination, and then substitute the calculated optimization combination and target temperature time into the temperature calculation model of the concrete water flow process established in S3 to calculate the concrete temperature T2 after water flow; S6.2.3 When the calculated concrete temperature T2 after variable combination is less than or equal to the target temperature T of the concrete cooling period M , greater than or equal to the allowable temperature T of concrete during cooling period c2 When , the flow rate, water temperature and water pipe spacing values ​​of this group of variable combinations are retained; When the calculated concrete temperature T2 after variable combination is greater than the target temperature T M Or less than the allowable temperature T during cooling process c2 , then discard the variable combination; S6.2.4 Calculate the temperature control costs of all variable combinations that meet the target temperature of the concrete cooling period in step S6.2.3 based on the temperature control cost function relationship of the cooling process in step S5, and select the variable combination with the smallest temperature control cost as the temperature control measure variable after optimization of the concrete cooling period.

2. The method for optimizing temperature control indexes during the whole process of water cooling of a concrete dam according to claim 1, characterized in that: The concrete temperature calculation model for the whole process of water flow through the concrete dam established in step S3 is: T c =T w +(T1-T w )φ(t)+θ0ψ(t) p=kga / 1.362S1S2 k=2.09-1.35ξ+0.32ξ 2 Where, T c T is the concrete temperature during the whole process of water supply to the concrete dam; w is the water temperature during the water flow process; T1 is the concrete pouring temperature; φ(t) is the water cooling function; θ0 is the final adiabatic temperature rise of concrete; ψ(t) is the adiabatic temperature rise function of concrete; p is the cooling coefficient of the water pipe; t is the water flow time; m is the adiabatic temperature rise coefficient of concrete, which is determined according to the engineering concrete experiment; k is the comprehensive water cooling coefficient; a is the thermal conductivity of concrete; S1 is the horizontal spacing of water pipes, and S2 is the vertical spacing of water pipes; λ is the thermal conductivity of concrete; L is the length of the water pipe; c w is the specific heat of water in the water supply measure; ρ w is the density of water in the water supply measure; q w For water flow.

3. The method for optimizing temperature control indexes during the whole process of water cooling of a concrete dam according to claim 1, characterized in that: The step S4 establishes a time calculation model for reaching the maximum temperature of the concrete heating period / the target temperature of the cooling period as follows: Where, T max / M T is the maximum temperature of concrete during the heating period or the target temperature of concrete during the cooling period; w is the water temperature; T1 is the concrete pouring temperature; p is the water pipe cooling coefficient.

4. The method for optimizing temperature control indexes during the whole process of water cooling of a concrete dam according to claim 1, characterized in that: The step S2 determines that the temperature control measure variables that need to be optimized during the whole process of concrete dam water supply include the temperature control measure variables during the concrete heating period and the temperature control measure variables during the concrete cooling period; The temperature control measure variables during the concrete heating period include water temperature, flow rate and water pipe spacing; The temperature control measure variables during the concrete cooling period include water temperature and flow rate; The upper limit value of water temperature during the concrete heating period is T w-max It is the natural temperature of the cooling water during water cooling; The lower limit of water temperature during the concrete heating period is T w·min for: Where: Δt w is the maximum temperature drop of cooling water; Q w is the rated cooling capacity of the cooling water system; c w is the specific heat capacity of water; m w T is the mass of cooling water required per hour; w·min T is the lower limit of water temperature during water cooling; w·max is the upper limit of water temperature during water cooling, k is the loss coefficient, which is 1.1 to 1.2; For the convenience of calculation, the upper and lower limits of the spacing between water pipes during the concrete heating period are reflected by the upper and lower limits of the total length of water pipes required in a casting bin; the upper limit of the total length of water pipes required in a casting bin L max for: Where, L max The maximum length of water pipe required to control the temperature of concrete in a pouring bin; is the minimum horizontal spacing of water pipes; The minimum longitudinal spacing of water pipes; d t is the total amount of concrete in a pouring bin; The lower limit of the total length of water pipes required in a casting bin is L min for: Where, L min The minimum length of water pipe required to control the temperature of concrete in a pouring bin; is the maximum horizontal spacing of water pipes; is the maximum longitudinal spacing of the water pipes; d t is the total amount of concrete in a pouring bin; The upper limit of water flow rate during concrete heating period q w·max and the lower limit q w·min Determined according to the technical standards for temperature control during the concrete heating period; The upper limit value of water temperature during the concrete cooling period is T w·max and the lower limit T w·min , flow upper limit value q w·max and the lower limit q w·min All of them are determined according to the temperature control technical standards during the concrete cooling period.

5. The method for optimizing temperature control indexes during the whole process of water cooling of a concrete dam according to claim 4 is characterized in that: During the concrete heating period, the temperature difference between the concrete temperature and the cooling water at the water inlet should not exceed 20°C; |T c -T w |≤20 Where, T c is the average temperature of concrete during the water flow process, T w It is the temperature of water in water cooling.

6. The method for optimizing temperature control indexes during the whole process of water cooling of a concrete dam according to claim 4, characterized in that: During the concrete cooling period, the temperature difference between the concrete temperature and the cooling water should not exceed 15°C, that is: |T w -T c |≤15 Where, T c is the average temperature of concrete during the water flow process of the concrete dam, T w The temperature of the water in the water cooling system; During the concrete cooling period, the water flow rate should not exceed 1.2m 3 / h is appropriate, that is: 0<q w ≤1.2 In the formula, q w It is the water flow rate during the cooling period.

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