Dynamic regulation and control method for water spraying maintenance of concrete warehouse surface in high-temperature season

Abstract

The invention belongs to the technical field of concrete curing, and particularly provides a high-temperature season concrete bin surface water spraying curing dynamic regulation and control method which comprises the steps that the temperature of a pouring bin is predicted by adopting a heat source pouring bin temperature calculation formula in combination with the actually measured temperature in the pouring bin, the water passing temperature and the water passing flow; an unmanned aerial vehicle airborne infrared thermal imaging technology is used for detecting and obtaining the initial temperature of the surface of the pouring bin; the surface temperature of the pouring bin is predicted in combination with the to-be-adopted maintenance water temperature or weather forecast; on the basis of a pouring bin surface water spraying maintenance measure optimization model, water spraying measures meeting the inside and outside allowable temperature difference and the surface allowable cooling rate are obtained through optimization; and in combination with optimal water spraying measures, preparing maintenance water with corresponding water temperature for water spraying maintenance. The method is used for dynamic regulation and control of concrete bin surface water spraying maintenance so as to obtain the water spraying maintenance effect meeting the inside and outside allowable temperature difference and the surface allowable cooling rate.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete curing, and in particular relates to a dynamic control method for water spraying curing of a concrete bin surface in a high temperature season. Background Art

[0002] After the large-volume concrete pouring bin is closed in the hot season, the concrete on the surface of the bin will be affected by the solar radiation heat, which will cause excessive surface temperature gradient, resulting in temperature stress exceeding the tensile strength of the concrete, thereby generating cracks that are detrimental to the structure; therefore, after the large-volume concrete pouring bin is closed in the hot season, necessary surface maintenance measures need to be taken to moisturize the bin surface to avoid cracks that endanger the safety of the structure.

[0003] At present, when pouring concrete in high temperature seasons, the method of spraying the surface of the silo to form a local microclimate is often used to reduce the impact of solar radiation heat. After the silo is closed, the top surface of the silo is maintained by sprinkling or rotating water spraying; when the silo is demoulded, the side is generally maintained by spraying water with a hanging pipe. At present, the traditional way to monitor the surface maintenance effect of the concrete silo is to have experienced technicians conduct manual inspections, which mainly rely on visual observation or some simple temperature measurement methods for evaluation. However, practice has shown that there are the following problems: (1) Due to the large area of ​​the large-volume concrete silo, especially the sides of some silos are located in high-level areas, manual inspections are not only time-consuming and labor-intensive, but also highly dangerous. (2) In the hot season, if the surface of the silo is not sprayed with water for maintenance, the surface will be dry and white, and a "high outside and low inside" temperature gradient will appear. At this time, if it encounters rain or suddenly sprays low-temperature water for maintenance, it is easy to produce cold shock, thereby generating large tensile stress, which is not conducive to the crack resistance of the structure. (3) In addition, for concrete casting silos with fast hydration rate and high final hydration temperature rise, such as pumped concrete, there will be a "high inside and low outside" type of internal and external temperature difference. At this time, spraying low-temperature water for curing is likely to cause large tensile stress due to the excessive internal and external temperature difference, which is also not conducive to the crack resistance of the structure. That is, in the hot season, if the water spraying curing measures on the surface of the casting silo are not appropriate, on the one hand, the traditional inspection method is time-consuming and labor-intensive, and on the other hand, it is easy to produce a large internal and external temperature difference or the surface temperature of the casting silo is too fast to cool down, which will cause cracks in the casting silo. Therefore, it is urgent to develop a dynamic control method for spraying water on the surface of the casting silo to ensure the construction quality of concrete engineering. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a dynamic control method for water spraying maintenance of concrete silo surface in high temperature season, which is used for dynamic control of water spraying maintenance of concrete silo surface to obtain a water spraying maintenance effect that meets the allowable temperature difference between inside and outside and the allowable surface cooling rate.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a dynamic control method for water spraying and curing of concrete silo surface in high temperature season, comprising the following steps: S1. Prediction of the internal temperature of the casting bin during the initial water cooling period: Combined with the measured temperature inside the casting bin, the water temperature and water flow rate, the casting bin temperature calculation formula with heat source is used to predict the casting bin temperature during the initial water cooling period. t Temperature at all times T in ( t ); S2. Detection of initial temperature of casting bin surface: Use the infrared thermal imaging technology onboard the drone to detect and obtain the initial temperature of the casting bin surface T sur0 ; S3. Casting bin surface temperature prediction: Combined with the proposed curing water temperature or weather forecast, predict the casting bin surface temperature; S4. Optimization of water spraying measures on the casting bin surface: Based on the optimization model of water spraying curing measures on the casting bin surface, water spraying measures that meet the allowable temperature difference between the inside and outside and the allowable surface cooling rate are preferably obtained; S5. Dynamic regulation of water spraying maintenance on the casting bin surface: Combined with the preferred water spraying measures, prepare maintenance water of corresponding water temperature for water spraying maintenance, and use the infrared thermal imaging technology onboard the drone to detect the surface temperature of the casting bin, and regulate the curing effect of the casting bin surface in real time.

[0006] In the preferred solution, in step S1, the temperature calculation formula of the heat source casting bin is: (1); is the water cooling function, and its expression is: ; p=dka / D 2 ; k= 2.09-1.35 x +0.320 x 2 ; ξ=λL / ( c w r w q w ); For metal water pipes: d =1.947( α 1 b ) 2 ; α 1 b=0.926exp[-0.0314(b / c-20)0.48], (20≤ b / c ≤130); For plastic water pipes: d =ln100 / [ln( b / c )+( l / l 1 )ln( c / r 0 )]; D = 2b = 2 × 0.5836 ( s 1 s 2 ) 1 / 2 ; For a single exponential adiabatic temperature rise i (τ) = i 0 (1- e -mτ ),but: P ( t )= m / ( m - p )( e -pt - e -mt ); For combined exponential adiabatic temperature rise ,but: ; Where: T w The water temperature is the water temperature; T 0 is the initial temperature of concrete, measured by a thermometer buried inside the pouring bin; t For cooling time; a is the thermal conductivity; D , b , c are the diameter, outer radius and inner radius of the equivalent cooling column respectively; r 0 is the inner radius of the polyethylene water pipe; l、l 1 are the thermal conductivity of concrete and water pipe respectively; s 1 , s 2 They are the horizontal and vertical spacing of cooling water pipes respectively; L is the cooling water pipe length;c w is the specific heat of cooling water; r w is the cooling water density; q w is the water flow rate; i 0 is the final value of the adiabatic temperature rise of single exponential concrete, i 1 and i 2 It is the combined index type concrete insulation temperature rise value; m is a single exponential adiabatic temperature rise rate, m 1 and m 2 is the combined exponential adiabatic temperature rise rate, P ( t ) represents the function related to the adiabatic temperature rise and water cooling of concrete, and τ represents the age of concrete.

[0007] In the preferred embodiment, in step S1, if multiple water temperatures are used for water cooling during the initial water cooling period, for [ t i , t ] period (i.e., the i-th water temperature), the temperature calculation formula of the pouring bin with heat source is: (2) ; Water cooling function The expression is: ; For a single exponential adiabatic temperature rise, The expression is: ; For the combined exponential adiabatic temperature rise, The expression is: ; Where: T wi Indicates i Water temperature T i express i -1 The concrete temperature when the water flow of the water barrier temperature ends and the water flow of the water barrier temperature i begins, Indicates i Water cooling function when water is flowing through the water temperature, p i Indicates i Water temperature when water is flowing p , t iTo change the water temperature or flow rate, when changing the water temperature or flow rate, the time t Need to start from 0.

[0008] In the preferred solution, in step S3, the casting bin surface temperature prediction includes the following situations: 1) When using river surface water for water spraying maintenance, combined with weather forecast T a ( t ), the surface temperature of the casting bin T sur Predict and calculate the rate of change of casting bin surface temperature , t Surface temperature of casting bin at all times T sur ( t ) is expressed as: T sur ( t )= T spw ( t )= T a ( t )+Δ b 1 (3); (4); Where: T a ( t ) Take the weather forecast temperature, Δ b 1 is the temperature increment affected by sunlight and the length of the water pipe from the water intake to the warehouse surface; i =0, T sur-t0 = T sur0 ; i Indicates ordinal number, T sur-ti express t i The surface temperature of the casting bin at the moment, T spw ( t ) indicates the spray water temperature; 2) When groundwater is used for water spraying maintenance, the surface temperature of the casting bin T sur The expression is: T sur = T spw = T gw+Δ b 2 (5); Where: T gw Take the groundwater temperature, Δ b 2 is the temperature increment affected by sunlight factors; 3) When using the cooling water pipe outlet water for water spraying maintenance, the surface temperature of the casting bin T sur The expression is: T sur = T spw = T pout +Δ b 3 (6); Where: T pout Take the cooling water pipe outlet water temperature, Δ b 3 is the temperature increment affected by sunlight.

[0009] In the preferred solution, in step S4, the preferred method of spraying water on the surface of the casting bin is: Combined with the site conditions, N The set of water spraying maintenance measures M = { M 1 , M 2 ,…, M N}, for each water spray maintenance measure M i According to the predicted casting bin surface temperature and surface temperature change rate in step S3, combined with the casting bin internal temperature predicted in step S1, the casting bin surface water spraying measure optimization model is selected based on the principle that the water spraying curing measure is simple and practical to operate, and the optimal water spraying curing measure is selected. The expression of the casting bin surface water spraying measure optimization model is: (7); Where: T spw Maintain water temperature for spraying; T spQ The flow rate for water spray maintenance; T spt It is the time for water spraying and curing; T in is the internal temperature of the casting bin; T sur is the surface temperature of the casting bin; [Δ T in / out] is the allowable internal and external temperature difference specified in the mass concrete specification; T a is the ambient temperature; R It is the radiant heat absorbed by the surface of the casting bin; β is the heat release coefficient of the casting bin surface; X is the coefficient; Optimal water spray maintenance measures M opt for: M opt = M k ; Right now: M opt = M k ={ T spw-k , T spQ-k , T spt-k}; Where: M k For the k water spraying measures; T spw-k、 T spQ-k、 T spt-k Respectively represent k The water temperature, water flow rate and water time of each water spraying measure.

[0010] In the preferred scheme, in step S5, based on the preferred water spraying curing measures in step S4, curing water of corresponding water temperature is prepared, and then water spraying curing is performed on the surface of the casting bin; at the same time, the actual surface temperature of the casting bin is obtained by detecting the infrared thermal imaging technology carried by the drone, and the curing effect of the casting bin surface is regulated in real time based on the allowable temperature difference between the inside and outside of the casting bin and the allowable cooling rate of the bin surface temperature.

[0011] The present invention provides a dynamic control method for water spraying and curing of concrete silo surface in high temperature season, which has the following beneficial effects: 1. In view of the problem that after the large-volume concrete pouring warehouse is closed in the hot season, manual inspection is time-consuming, labor-intensive and dangerous due to complex on-site conditions. It is proposed to use an infrared thermal imaging camera onboard a drone to inspect the maintenance condition of the concrete pouring warehouse surface to improve the inspection efficiency and solve the problem of time-consuming and labor-intensive manual inspection.

[0012] 2. In view of the problem that in high temperature seasons, if the water spraying maintenance measures on the surface of the casting silo are not appropriate, it is easy to produce too large a temperature difference between the inside and outside of the casting silo or the cooling rate of the surface temperature of the casting silo is too large, which leads to cracks in the casting silo. An optimization model for the water spraying maintenance measures on the surface of the casting silo is proposed with the allowable temperature difference between the inside and outside of the casting silo and the allowable cooling rate of the silo surface as the target, which solves the problem of cracks in the structure caused by blind water spraying maintenance on the surface of the casting silo. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 This is the technical roadmap for dynamic control of water spray curing on the surface of the casting bin in high temperature season of the present invention; Figure 2 Actual picture of the temperature calibration of infrared detection onboard drone; Figure 3 This is the infrared detection temperature diagram of the initial temperature of the casting bin surface; Figure 4 Predict the temperature inside the casting bin and the temperature process curve on the surface; Figure 5 Infrared detection temperature image during the water spraying curing stage on the casting bin surface. DETAILED DESCRIPTION

[0014] A dynamic control method for water spraying maintenance of concrete silo surface in high temperature season, such as Figure 1 As shown, the following steps are included: S1: Prediction of the internal temperature of the casting bin during the initial water cooling period. The temperature is measured by the thermometer buried inside the casting bin. T 0 , combined with the water temperature and water flow, the temperature calculation formula of the casting bin with heat source is used to predict the casting bin temperature. t Temperature at all times T in ( t ).

[0015] The temperature calculation formula of the pouring bin with heat source is: (1); Water cooling function for: ; in, p=dka / D 2 , k= 2.09-1.35 x +0.320 x 2 , ξ=λL / ( c w r w q w) .

[0016] For metal water pipes: d =1.947( α 1 b ) 2 ; α 1 b =0.926exp[-0.0314(b / c-20)0.48] , (20≤ b / c ≤130); For plastic water pipes: d =ln100 / [ln( b / c )+( l / l 1 )ln( c / r 0 )] ; D = 2b = 2 × 0.5836 ( s 1 s 2 ) 1 / 2 ; For a single exponential adiabatic temperature rise i (τ) = i 0 (1- e -mτ ), P ( t ) is: P ( t )= m / ( m - p )( e -pt - e -mt ); For combined exponential adiabatic temperature rise , P ( t ) is: ; If during the initial water cooling period, multiple water temperatures are used for water cooling, for [ t i , t ] period (i.e. i When the water temperature is blocked), the temperature calculation formula of the pouring bin with heat source is: (2); Water cooling function for: ; For a single exponential adiabatic temperature rise, P ( t ) is: ; For the combined exponential adiabatic temperature rise, P ( t ) is: ; Where: T w The water temperature is the water temperature; T 0 is the initial temperature of concrete; t For cooling time; a is the thermal conductivity; D , b , c are the diameter, outer radius and inner radius of the equivalent cooling column respectively; r 0 is the inner radius of the polyethylene water pipe; l、l 1 are the thermal conductivity of concrete and water pipe respectively; s 1 , s 2 They are the horizontal and vertical spacing of cooling water pipes respectively; L is the cooling water pipe length; c w is the specific heat of cooling water; r w is the cooling water density; q w is the water flow rate; i 0 is the final value of the adiabatic temperature rise of single exponential concrete, i 1 and i 2 It is the combined index type concrete insulation temperature rise value; m is a single exponential adiabatic temperature rise rate, m 1 and m 2 is the combined exponential adiabatic temperature rise rate.

[0017] S2: Detection of initial temperature of casting bin surface. First, the infrared detection temperature of drone is calibrated based on different temperatures. Then, the temperature of casting bin surface is detected by using the infrared thermal imaging technology temperature detection function of drone. The initial temperature of casting bin surface is obtained.T sur0 .

[0018] S3: Prediction of casting bin surface temperature.

[0019] 1) When using river surface water for water spraying maintenance, combined with weather forecast T a ( t ), the surface temperature of the casting bin T sur Predict and calculate the rate of change of casting bin surface temperature .

[0020] T sur ( t )= T spw ( t )= T a ( t )+Δ b 1 (3); (4); Where: T a Take the weather forecast temperature, Δ b 1 is the temperature increment affected by sunlight and the length of the water pipe from the water intake to the warehouse surface; i =0, .

[0021] 2) When groundwater is used for water spraying maintenance, the groundwater temperature is relatively stable and the water temperature fluctuation is relatively small. T sur The expression is: T sur = T spw = T gw +Δ b 2 (5); Where: T gw Take the groundwater temperature, Δ b 2 is the temperature increment affected by factors such as sunlight.

[0022] 3) When using the cooling water pipe outlet water for water spray maintenance, T sur The expression is: T sur= T spw = T pout +Δ b 3 (6); Where: T pout Take the cooling water pipe outlet water temperature, Δ b 3 is the temperature increment affected by factors such as sunlight.

[0023] S4: Optimization of water spraying measures on the casting bin surface. Combined with the site conditions, give N The set of water spraying maintenance measures M = { M 1 , M 2 ,…, M N}, for each water spray maintenance measure M i According to the predicted casting bin surface temperature and surface temperature change rate in step 3, combined with the predicted casting bin internal temperature in step 1, the casting bin surface water spraying measures optimization model is obtained by formula (7). The optimal water spraying curing measures are selected based on the principle that the water spraying curing measures are simple and practical. M opt = M k ,Right now M opt = M k ={ T spw-k , T spQ-k , T spt-k}.

[0024] (7); Where: T spw Maintain water temperature for spraying; T spQ The flow rate for water spray maintenance; T spt It is the time for water spraying and curing; T in is the internal temperature of the casting bin; T sur is the surface temperature of the casting bin; Δ T in / out The permissible internal and external temperature difference is specified in the mass concrete specification, which is generally 20~25℃; T a is the ambient temperature; R It is the radiant heat absorbed by the surface of the casting bin;β is the heat release coefficient of the casting bin surface; X is the coefficient.

[0025] S5: Dynamic regulation of water spray curing on the casting bin surface. Based on the preferred water spray curing measures in step 4, prepare curing water of the corresponding water temperature in advance, and then perform water spray curing on the casting bin surface; at the same time, use the infrared thermal imaging technology onboard the drone to detect and obtain the actual surface temperature of the casting bin, and based on the allowable temperature difference inside and outside the casting bin and the allowable cooling rate of the bin surface temperature, regulate the curing effect of the casting bin surface in real time.

[0026] Example analysis: Take a concrete water project in a construction period in the hot season in Central China as an example. The thickness of the bottom slab casting bin is 3m. Pumped concrete is used. The concrete insulation temperature rise is i ( t )=50.25(1-e -0.66τ )℃, PVC plastic water pipes are used for water cooling, the water pipe spacing is 1.0m×1.5m, the outer diameter is 32mm, the inner diameter is 28mm, the water pipe length is 200m, the water flow rate is 20L / min, and groundwater is used for water cooling. The water temperature in July is 22℃, and the water flow time is 7d. c The thermal conductivity is 0.95 kJ / (kg·℃), is 8.99 kJ / (m·h·°C), density 2400 kg / m 3 , surface heat release coefficient 47.52 kJ / (m 2 ·h·°C), specific heat of water c w The density of water is 4.187 kJ / (kg·℃). 1000 kg / m 3 The surface temperature of the casting bin was detected using infrared technology using a drone DJI Mavic 3T equipped with a dual-light camera.

[0027] Step 1: Prediction of the internal temperature of the casting bin during the initial water cooling period.

[0028] The initial temperature of the concrete bottom plate is 27.5℃. According to the water pipe spacing, water supply measures, and thermal parameters of concrete and water, the temperature calculation formula (1) of the pouring bin with heat source is calculated as follows: T in ( t )=22+(27.5-22) e -0.0777t +50.25× 0.66 / (0.66-0.0777)( e-0.0777t - e -0.66t ) Step 2: Detect the initial temperature of the casting bin surface.

[0029] Before using the drone to measure the surface temperature of the casting bin, infrared photography was performed based on three different water temperatures (13°C, 32°C, and 50°C), and a temperature sensor was used to monitor the water temperature changes in real time, and then the drone-mounted infrared detection temperature was calibrated, as shown in the attached figure. Figure 2 After multiple shooting and comparison, the measured temperature error is within the range of 0±0.2℃, which can meet the demand for casting bin surface temperature detection.

[0030] The drone was placed near the casting bin and took off smoothly to the top of the casting bin. After hovering for 1 minute, multiple infrared images were taken. The drone infrared thermal imaging technology was used to detect that the initial maximum temperature of the casting bin surface was 32.2°C, the minimum temperature was 30.1°C, and the average temperature was T sur0 =31.1℃, as attached Figure 3 shown.

[0031] S3: Prediction of casting bin surface temperature.

[0032] Since the line from the river to the casting bin is long and difficult to implement, groundwater or water from the outlet of the casting bin cooling water pipe is used for water spraying maintenance.

[0033] (1) When groundwater is used for spraying maintenance, the average monthly groundwater temperature in July is 22°C. Affected by factors such as sunshine, the spraying water used for maintenance fluctuates slightly by about 3°C.

[0034] (2) When using the outlet water of the cooling water pipe of the casting bin for water spraying maintenance, the outlet water is collected in the water collection tank. To avoid the water temperature of the water collection tank being too high, the water in the water collection tank is replaced every 12 hours. Therefore, the water temperature of the water spraying maintenance water fluctuates periodically, and the water temperature of the water spraying is 23~42.2℃. As the temperature of the casting bin increases, the outlet water temperature also increases, and the water temperature of the water spraying maintenance water also increases.

[0035] The surface predicted temperature process lines of the two methods of water spray curing calculation are shown in the attached figure. Figure 4 shown.

[0036] S4: Optimal water spraying measures on the casting bin surface.

[0037] Combined with the on-site conditions, three types of water spray maintenance measures are given: M 1 Use groundwater as spray curing water, the spray water temperature is 22~25℃, the spray flow rate is 2L / min, and the spraying method is continuous spraying; M 2 Use groundwater as water for spraying and curing, the water temperature is 22~25℃, the water flow rate is 2L / min, and the water is sprayed for 30 minutes with an interval of 30 minutes; M 3 The outlet water of the cooling water pipe of the casting bin is used as the water for spraying and curing. The water temperature is 23~42.2℃, the water flow rate is 4L / min, and the water is sprayed in a continuous spraying mode.

[0038] By the attached Figure 4 The predicted temperature inside the casting bin and the surface temperature are used to calculate the temperature difference between the inside and outside of the casting bin. It can be seen that since the project uses pumped concrete, the cement hydration temperature increases.

[0039] The effects of the three water spraying maintenance measures are as follows: (1) When groundwater is continuously used for water spraying on the surface of the casting bin for curing, the temperature difference between the inside and outside caused exceeds 35°C, which does not meet the allowable temperature difference of 20~25°C specified in the specification, and is likely to cause cracks in the concrete structure. (2) When groundwater is intermittently used for water spraying on the surface of the casting bin, when water is sprayed again after the intermittent spraying, a "cold shock" phenomenon is likely to occur during operation, which is not conducive to the stress of the casting bin surface. (3) When water spraying is performed at the outlet of the cooling water pipe, although the outlet water temperature is relatively high, except when the water in the sump is replaced, which causes the temperature difference between the inside and outside of the casting bin to not meet the allowable temperature difference specified in the specification, the allowable temperature difference specified in the specification can be met most of the time.

[0040] Combined with the optimization model of water spray curing measures on the surface of the casting bin, the water spray curing measures are simple and practical to operate, and the water spray measures that meet the allowable temperature difference between the inside and outside and the allowable surface cooling rate are selected. M 3 .

[0041] S5: Dynamic control of water spray curing on the casting bin surface. After the concrete casting bin is finally set, the temperature of the casting bin rises due to the combined effects of cement hydration reaction and direct sunlight. In order to prevent the surface temperature gradient from being too large and the surface from losing water and shrinking, etc., which may cause surface cracking, water spray curing is carried out using the outlet water of the casting bin cooling water pipe. At the same time, the infrared thermal imaging technology onboard the drone is used to detect the actual temperature of the casting bin surface. Figure 5 The drone was placed near the water spray curing area of ​​the casting bin, and took off smoothly to the top of the water spray curing area. After hovering for 1 minute, multiple infrared images were taken. The drone infrared thermal imaging technology was used to detect that the highest temperature in the water spray curing area was 38.7°C, the lowest temperature was 36.1°C, and the average temperature T sur =37.4℃. At this time, the internal temperature of the casting bin is T in =59.63℃, the temperature difference between inside and outside is Δ Tin / out =22.23℃, which meets the allowable temperature difference between inside and outside, indicating that the water spraying curing effect on the casting bin surface is good; however, when the water in the sump is replaced, the surface temperature drops at a large rate, and the water spraying temperature drops by about 10℃ in a short time. It is recommended to reduce the water spraying flow rate when replacing the water in the sump to reduce the cooling rate of the casting bin surface temperature.

[0042] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A dynamic control method for water spraying and curing of concrete silo surface in high temperature season, characterized in that: The following steps are involved: S1. Prediction of the internal temperature of the casting bin during the initial water cooling period: Combined with the measured temperature inside the casting bin, the water temperature and water flow rate, the casting bin temperature calculation formula with heat source is used to predict the casting bin temperature during the initial water cooling period. t Temperature at all times T in ( t ); S2. Detection of initial temperature of casting bin surface: Use the infrared thermal imaging technology onboard the drone to detect and obtain the initial temperature of the casting bin surface T sur0 ; S3. Casting bin surface temperature prediction: Combined with the proposed curing water temperature or weather forecast, predict the casting bin surface temperature; S4. Optimization of water spraying measures on the casting bin surface: Based on the optimization model of water spraying curing measures on the casting bin surface, water spraying measures that meet the allowable temperature difference between the inside and outside and the allowable surface cooling rate are preferably obtained; S5. Dynamic regulation of water spraying maintenance on the casting bin surface: Combined with the preferred water spraying measures, prepare maintenance water of corresponding water temperature for water spraying maintenance, and use the infrared thermal imaging technology onboard the drone to detect the surface temperature of the casting bin, and regulate the curing effect of the casting bin surface in real time.

2. The method for dynamic control of water spraying and curing of concrete silo surface in high temperature season according to claim 1 is characterized in that: In step S1, the temperature calculation formula of the heat source casting bin is: (1)； is the water cooling function, and its expression is: ； p=dka / D 2 ； k= 2.09-1.35 ξ +0.320 ξ 2 ； ξ = λL / ( c w ρ w q w )； For metal water pipes: d =1.947( α 1 b ) 2 ； α 1 b =0.926exp[-0.0314(b / c-20)0.48],(20≤ b / c ≤130); For plastic water pipes: d =ln100 / [ln( b / c )+( λ / λ 1)ln( c / r 0)]; D=2b=2×0.5836( s 1 s 2) 1 / 2 ; For a single exponential adiabatic temperature rise θ (τ) = θ 0(1- e -mτ ),but: Ψ ( t )= m / ( m - p )( e -pt - e -mt )； For combined exponential adiabatic temperature rise ,but: ； Where: T w The water temperature is the water temperature; T 0 is the initial temperature of concrete, measured by a thermometer buried inside the pouring bin; t For cooling time; a is the thermal conductivity; D , b , c are the diameter, outer radius and inner radius of the equivalent cooling column respectively; r 0 is the inner radius of the polyethylene water pipe; λ, λ 1 are the thermal conductivity of concrete and water pipe respectively; s 1. s 2 are the horizontal and vertical spacing of cooling water pipes respectively; L is the cooling water pipe length; c w is the specific heat of cooling water; ρ w is the cooling water density; q w is the water flow rate; θ 0 is the final value of the single exponential concrete adiabatic temperature rise, θ 1 and θ 2 is the combined index type concrete insulation temperature rise value; m is a single exponential adiabatic temperature rise rate, m 1 and m 2 is the combined exponential adiabatic temperature rise rate, Ψ ( t ) represents the function related to the adiabatic temperature rise and water cooling of concrete, and τ represents the age of concrete.

3. The method for dynamic control of water spraying and curing of concrete silo surface in high temperature season according to claim 2 is characterized in that: In step S1, if multiple water temperatures are used for water cooling during the initial water cooling period, for [ t i , t ] period, the temperature calculation formula of the casting bin with heat source is: (2)； Water cooling function The expression is: ； For a single exponential adiabatic temperature rise, The expression is: ； For the combined exponential adiabatic temperature rise, The expression is: ； Where: T wi Indicates i Water temperature T i express i -1 The water temperature is over and the water flow is completed. i The concrete temperature when the water barrier starts to flow, Indicates i Water cooling function when water is flowing through the water temperature, p i Indicates i Water temperature when water is flowing p , t i To change the water temperature or flow rate, the time t Need to start from 0.

4. The method for dynamic control of water spraying and curing of concrete silo surface in high temperature season according to claim 1, characterized in that: In step S3, the casting bin surface temperature prediction includes the following situations: 1) When using river surface water for water spraying maintenance, combined with weather forecast T a ( t ), the surface temperature of the casting bin T sur Predict and calculate the rate of change of casting bin surface temperature , t Surface temperature of casting bin at all times T sur ( t ) is expressed as: T sur ( t )= T spw ( t )= T a ( t )+D b 1(3); (4)； Where: T a ( t ) Take the weather forecast temperature, Δ b 1 is the temperature increment affected by sunlight and the length of the water pipe from the water intake to the warehouse surface; when i =0, T sur-t0 = T sur0 ; i Indicates ordinal number, T sur-ti express t i The surface temperature of the casting bin at the moment, T spw ( t ) indicates the spray water temperature; 2) When groundwater is used for water spraying maintenance, the surface temperature of the casting bin T sur The expression is: T sur = T spw = T gw +D b 2 (5); Where: T gw represents the groundwater temperature, Δ b 2 is the temperature increment affected by sunlight factors; 3) When using the cooling water pipe outlet water for water spraying maintenance, the surface temperature of the casting bin T sur The expression is: T sur = T spw = T pout +D b 3 (6); Where: T pout Indicates the outlet water temperature of the cooling water pipe, Δ b 3 is the temperature increment affected by sunlight.

5. The method for dynamic control of water spraying and curing of concrete silo surface in high temperature season according to claim 1, characterized in that: In step S4, the preferred method for spraying water on the surface of the casting bin is: Combined with the site conditions, N The set of water spraying maintenance measures M = { M 1, M 2,…, M N }, for each water spray maintenance measure M i According to the predicted casting bin surface temperature and surface temperature change rate in step S3, combined with the casting bin internal temperature predicted in step S1, the casting bin surface water spraying measure optimization model is selected based on the principle that the water spraying curing measure is simple and practical to operate, and the optimal water spraying curing measure is selected. The expression of the casting bin surface water spraying measure optimization model is: (7)； Where: T spw Maintain water temperature for spraying; T spQ The flow rate for water spray maintenance; T spt It is the time for water spraying and curing; T in is the internal temperature of the casting bin; T sur is the surface temperature of the casting bin; [Δ T in / out ] is the allowable internal and external temperature difference specified in the mass concrete specification; T a is the ambient temperature; R It is the radiant heat absorbed by the surface of the casting bin; β is the heat release coefficient of the casting bin surface; X is the coefficient; Optimal water spray maintenance measures M opt for: M opt = M k ； Right now: M opt = M k ={ T spw-k , T spQ-k , T spt-k }； Where: M k For the k Water spraying measures, T spw-k、 T spQ-k、 T spt-k Respectively represent k The water temperature, water flow rate and water time of each water spraying measure.

6. The method for dynamic control of water spraying and curing of concrete silo surface in high temperature season according to claim 1, characterized in that: In step S5, based on the preferred water spraying curing measure of step S4, curing water of corresponding water temperature is prepared, and then water spraying curing is performed on the surface of the casting bin; at the same time, the actual surface temperature of the casting bin is obtained by detecting the infrared thermal imaging technology carried by the drone, and based on the allowable temperature difference between the inside and outside of the casting bin and the allowable cooling rate of the bin surface temperature, the curing effect of the casting bin surface is regulated in real time.

Images