Temperature-synergistic deformation-based wall body crack control method

Abstract

The application discloses a wall crack control method based on temperature cooperative deformation and belongs to the technical field of concrete construction. The wall crack control method based on temperature cooperative deformation comprises the following steps: obtaining conductive material, setting conductive concrete mix proportion, measuring the resistivity and specific heat capacity of the conductive concrete, obtaining the resistance between electrodes, calculating the electrode spacing, pre-burying a first temperature sensor and electrodes in a guide wall, pouring a bottom plate by using ordinary concrete, pouring the guide wall by using conductive concrete, pre-burying a second temperature sensor in the wall, pouring the wall by using ordinary concrete, adjusting the power-on parameters of the electrodes, synchronizing the temperature change rate of the guide wall with the temperature change rate of the wall, and disconnecting the power supply of the electrodes when the temperature of the wall drops to the ambient temperature. The application can make the temperature deformation of the guide wall and the wall dynamically cooperative, eliminate the shrinkage difference caused by the temperature difference, further reduce the restraint stress of the wall and the bottom plate interface, inhibit the cracks of the super-long concrete structure, and improve the waterproofness and construction efficiency of the overall structure.

Description

Technical Field

[0001] This invention relates to the field of concrete construction technology, and in particular to a method for controlling wall cracking based on temperature-coordinated deformation. Background Technology

[0002] Ultra-long concrete structures refer to reinforced concrete or prestressed concrete structures whose length or span far exceeds the conventional design limits. Due to the limitations of construction conditions, different parts of such structures are usually constructed by layering and segmenting. However, the shrinkage and deformation of concrete poured at different times are not synchronized due to the age difference, which significantly amplifies the shrinkage deformation and temperature difference deformation effects of the concrete.

[0003] Specifically, the base slab of ultra-long concrete structures is usually poured first and hardened earlier. When the wall concrete poured later shrinks, its deformation will be strongly constrained by the base slab, resulting in significant shrinkage stress concentration in the junction area of ​​the wall and the base. This leads to tensile cracking failure of the concrete components, eventually forming irregular cracks, which seriously affects the durability and load-bearing capacity of the concrete structure. Summary of the Invention

[0004] This invention aims to address at least one of the technical problems existing in the prior art. To this end, this invention proposes a wall crack control method based on temperature-coordinated deformation, which can reduce wall shrinkage stress and lower the risk of cracking by controlling the volume deformation of the concrete base slab and wall in synergy with temperature.

[0005] According to an embodiment of the present invention, a wall crack control method based on temperature-coordinated deformation is applied to the wall bottom junction area of ​​an ultra-long concrete structure. A guide wall is provided between the wall and the bottom plate, and the wall is connected to the bottom plate through the guide wall. Multiple electrodes and multiple first temperature sensors are embedded in the guide wall. The multiple electrodes are evenly distributed in the guide wall and are all connected to a power source through wires. The multiple first temperature sensors are evenly distributed in the guide wall and are used to monitor the temperature changes inside the guide wall. Multiple second temperature sensors are embedded in the wall and are evenly distributed in the wall and are used to monitor the temperature changes inside the wall.

[0006] Wall crack control methods include:

[0007] S1: Obtain conductive materials, set the mix proportion of conductive concrete based on design requirements and construction specifications, and determine the resistivity and specific heat capacity of conductive concrete after the preset curing period through experiments;

[0008] S2: Calculate the resistance between electrodes based on resistivity, calculate the heat required for the conductive concrete to heat up based on specific heat capacity, and obtain the electrode spacing based on resistance and heat required for the conductive concrete to heat up.

[0009] S3: Embed the first temperature sensor in the pre-casting area of ​​the guide wall, embed the electrode in the pre-casting area of ​​the guide wall according to the electrode spacing, use ordinary concrete to cast the base plate to the bottom elevation of the guide wall, and use conductive concrete to cast the guide wall to the bottom elevation of the wall.

[0010] S4: Embed a second temperature sensor in the pre-casting area of ​​the wall, and use ordinary concrete to cast the wall to the top elevation of the wall;

[0011] S5: Adjust the electrode energizing parameters based on the real-time monitoring results of the first and second temperature sensors to synchronize the temperature change rate of the guide wall with the temperature change rate of the wall. Disconnect the electrode power supply when the wall temperature drops to the ambient temperature.

[0012] The wall crack control method based on temperature-coordinated deformation according to embodiments of the present invention has at least the following beneficial effects: Utilizing the electrothermal properties of conductive concrete, the guide wall is used as an active heat source. The Joule heating generated by energizing the electrodes regulates the internal temperature of the guide wall. Simultaneously, a closed-loop feedback control system is constructed by combining multi-level temperature sensors arranged in the guide wall and the wall body to dynamically adjust the heating power and energizing time, so that the temperature deformation of the guide wall and the wall body is dynamically coordinated, eliminating the shrinkage difference caused by temperature difference, thereby significantly reducing the constraint stress at the interface between the wall body and the base plate, suppressing transverse through cracks in ultra-long concrete structures, solving the problem that traditional passive curing is difficult to cope with complex temperature change environments, and reducing the use of construction joints and post-pouring strips, improving the overall structural waterproofing and construction efficiency.

[0013] According to some embodiments of the present invention, in S2, the electrode spacing is obtained based on the heat required for the conductive concrete to heat up, and the electrode spacing is calculated using the following formula:

[0014]

[0015] In the formula, l is the electrode spacing, U is the voltage across the conductor wall, t is the energizing time of the conductor wall, ρ is the resistivity of the conductor wall, G is the bulk density of the conductor wall, T is the rising temperature of the conductor wall, and c is the specific heat capacity of the conductor wall.

[0016] According to some embodiments of the present invention, in S3, the pre-embedded electrodes are insulated from the reinforcing bars of the base plate structure and the reinforcing bars of the guide wall structure.

[0017] According to some embodiments of the present invention, in S3, the depth to which the bottom of the electrode is embedded in the guide wall is at least [amount missing] of the guide wall thickness.

[0018] According to some embodiments of the present invention, in S3, the guide wall includes: a first section, which is disposed between the wall and the base plate, and extends along the extension direction of the wall to connect with the base plate, wherein a plurality of electrodes are uniformly arranged inside the first section; and a second section, which is disposed on the first section, protruding from the surface of the wall and connected with the base plate, wherein at least a portion of the cross-sectional area of ​​the second section gradually decreases in the direction away from the base plate, so as to reduce the shrinkage difference between the guide wall and the wall due to the temperature difference, thereby suppressing temperature cracks.

[0019] According to some embodiments of the present invention, in S3, a plurality of first temperature sensors are uniformly arranged in the horizontal direction on the straight line where the geometric center of the guide wall is located.

[0020] According to some embodiments of the present invention, in S3, each electrode surface is provided with threads, which are configured to make the connection between the electrode and the concrete tighter.

[0021] According to some embodiments of the present invention, in S4, the second temperature sensor includes a first temperature sensing unit and a second temperature sensing unit. A plurality of first temperature sensing units are uniformly arranged in the horizontal direction on a straight line where the geometric center of the wall is located, and a plurality of second temperature sensing units are uniformly arranged in the horizontal direction on the surface of the wall. The first temperature sensing units and the second temperature sensing units cooperate to monitor the temperature difference between the inner and outer surfaces of the wall.

[0022] According to some embodiments of the present invention, in step S4, before pouring the wall with ordinary concrete to the top elevation of the wall, the following steps are also included: curing the base slab and the guide wall; after completing the curing of the base slab and the guide wall, the guide wall is roughened.

[0023] According to some embodiments of the present invention, in S5, the real-time monitoring and adjustment of the electrode energizing parameters based on the first and second temperature sensors includes: acquiring the temperature change curve of the wall concrete according to the real-time monitoring data of the second temperature sensor; determining whether the concrete has reached its final setting state according to the concrete mix ratio and the on-site concrete condition; monitoring the center temperature of the guide wall and the center temperature of the wall in real time through the first and second temperature sensors; dynamically adjusting the power output when the wall concrete reaches its final setting state to keep the temperature difference between the center of the guide wall and the wall within ±10℃; controlling the cooling rate of the guide wall to be synchronized with the cooling rate of the wall after the wall concrete temperature reaches its peak; and stopping the power supply and transferring the wall and guide wall to routine curing when both the wall and guide wall temperatures drop to ambient temperature.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0026] Figure 1 This is a flowchart illustrating the wall crack control method based on temperature-coordinated deformation in this specific embodiment.

[0027] Figure 2 This specific embodiment illustrates the structure of the guide wall in the wall crack control method based on temperature-coordinated deformation;

[0028] Figure 3 for Figure 2 A cross-sectional schematic diagram.

[0029] Figure label:

[0030] Wall 10, base 20;

[0031] Guide wall 100, first section 110, second section 120;

[0032] First temperature sensor 200;

[0033] Electrode 300, wire 310, power supply 320;

[0034] Second temperature sensor 400, first temperature sensing unit 410, second temperature sensing unit 420. Detailed Implementation

[0035] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0036] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the stated number, and "above," "below," "within," etc. are understood to include the stated number. If "first," "second," etc. are used in the description, they are only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0037] In the description of this invention, unless otherwise explicitly defined, terms such as "set", "install", and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0038] Please refer to Figures 1 to 3 This embodiment discloses a wall crack control method based on temperature-coordinated deformation, applied to the wall bottom junction area of ​​an ultra-long concrete structure. A guide wall 100 is provided between the wall 10 and the base plate 20. The wall 10 is connected to the base plate 20 through the guide wall 100. Multiple electrodes 300 and multiple first temperature sensors 200 are embedded in the guide wall 100. The multiple electrodes 300 are evenly distributed in the guide wall 100. All multiple electrodes 300 are connected to a power supply 320 through wires 310. The multiple first temperature sensors 200 are evenly distributed in the guide wall 100 and are used to monitor the temperature changes inside the guide wall 100. Multiple second temperature sensors 400 are embedded in the wall 10 and are evenly distributed in the wall 10. The second temperature sensors 400 are used to monitor the temperature changes inside the wall 10.

[0039] Wall crack control methods include:

[0040] S1: Obtain conductive materials, set the mix proportion of conductive concrete based on design requirements and construction specifications, and determine the resistivity and specific heat capacity of conductive concrete after the preset curing period through experiments;

[0041] S2: Calculate the resistance between electrodes 300 based on resistivity, calculate the heat required for the conductive concrete to heat up based on specific heat capacity, and obtain the electrode spacing based on resistance and heat required for the conductive concrete to heat up.

[0042] S3: Embed the first temperature sensor 200 in the preset pouring area of ​​the guide wall 100, embed the electrode 300 in the preset pouring area of ​​the guide wall 100 according to the electrode spacing, pour the base plate 20 with ordinary concrete to the bottom elevation of the guide wall 100, and pour the guide wall 100 with conductive concrete to the bottom elevation of the wall 10.

[0043] S4: Embed the second temperature sensor 400 in the pre-casting area of ​​the wall 10, and use ordinary concrete to cast the wall 10 to the top elevation of the wall 10.

[0044] S5: Adjust the power supply parameters of electrode 300 based on the real-time monitoring results of the first temperature sensor 200 and the second temperature sensor 400 so that the temperature change rate of the guide wall 100 is synchronized with the temperature change rate of the wall 10. When the temperature of the wall 10 drops to the ambient temperature, disconnect the power supply 320 of electrode 300.

[0045] By utilizing the electrothermal properties of conductive concrete, the guide wall 100 is used as an active heat source. The Joule heating generated by the energization of the electrodes 300 regulates the internal temperature of the guide wall 100. At the same time, combined with multi-level temperature sensors arranged in the guide wall 100 and the wall 10, a closed-loop feedback control system is constructed to dynamically adjust the heating power and energization time, so that the temperature deformation of the guide wall 100 and the wall 10 are dynamically coordinated, eliminating the shrinkage difference caused by temperature difference. This significantly reduces the constraint stress at the interface between the wall 10 and the base plate 20, suppresses transverse through cracks in ultra-long concrete structures, solves the problem that traditional passive curing cannot cope with complex temperature change environments, and reduces the use of construction joints and post-pouring strips, improving the overall waterproofness and construction efficiency of the structure.

[0046] In some specific embodiments of the present invention, in S2, the electrode spacing is obtained based on the heat required for the conductive concrete to heat up, and the electrode spacing is calculated using the following formula:

[0047]

[0048] In the formula, l is the electrode spacing, U is the voltage across the conductor wall, t is the energizing time of the conductor wall, ρ is the resistivity of the conductor wall, G is the bulk density of the conductor wall, T is the rising temperature of the conductor wall, and c is the specific heat capacity of the conductor wall.

[0049] It should be noted that the formula for calculating the electrode spacing is derived through the following steps:

[0050] The conductive concrete was tested, and the resistance between the two electrodes at 300° was calculated using the following formula based on the resistivity ρ of the conductive concrete obtained from the test:

[0051]

[0052] In the formula, R is the resistance of the conductive concrete (Ω), ρ is the resistivity of the conductive concrete (Ω·m), l is the distance between the two electrodes (m), and s is the cross-sectional area of ​​the conductive wall (m²). 2 ;

[0053] Based on the specific heat capacity c of the conductive concrete obtained from the experiment, the heat required for the temperature of the conductive concrete between the two electrodes (300°) to rise by T is calculated using the following formula:

[0054] Q = VGTc;

[0055] In the formula, Q is the heat in J, and V is the volume of conductive concrete in m³. 3 G is the unit weight of conductive concrete (kg / m³). 3 T is the temperature rise in °C, and c is the specific heat capacity of conductive concrete in J / kg·°C.

[0056] Treating electrode 300 and conductive concrete as a purely resistive circuit, according to Joule's law, we can obtain:

[0057]

[0058] In the formula, Q′ is the heat generated by the current passing through the conductive concrete (J), U is the voltage across the conductive concrete (V), and t is the energizing time (s).

[0059] Assuming the heat required for the conductive concrete to rise to temperature T is provided by electrical energy conversion, then the following formula holds:

[0060] Q′=Q;

[0061] Right now,

[0062]

[0063] Therefore, the electrode spacing can be determined as follows:

[0064]

[0065] In the formula, l is the electrode spacing, U is the voltage across the conductor wall, t is the energizing time of the conductor wall, ρ is the resistivity of the conductor wall, G is the bulk density of the conductor wall, T is the rising temperature of the conductor wall, and c is the specific heat capacity of the conductor wall.

[0066] In some specific embodiments of the present invention, in S3, the pre-embedded electrode 300 is insulated from the structural steel bars of the base plate 20 and the structural steel bars of the guide wall 100 to prevent the current from forming a short circuit or shunting through the steel bar network when the electrode 300 is energized, ensuring that the electrical energy is concentrated and converted into Joule heat of the concrete of the guide wall 100. It should be noted that the conductive path between the electrode 300 and the steel bars can be cut off by physical isolation, specifically, by coating the steel bars with an insulating coating or installing a plastic sleeve, so that the current flows strictly in the conductive concrete according to the design path, ensuring the stability and controllability of the heating efficiency, while preventing stray currents from causing electrochemical corrosion to the structural steel bars and maintaining the durability of the concrete structure.

[0067] In some specific embodiments of the present invention, in S3, the depth to which the bottom of the electrode 300 is embedded in the guide wall 100 is at least [amount missing] of the thickness of the guide wall 100. This ensures that the heat generated by the electrode 300 can fully cover the entire cross-section of the guide wall 100, forming a uniform and stable temperature field. Specifically, by deeply embedding the electrode 300 to the bottom of the guide wall 100, the current path can penetrate the entire thickness of the concrete, avoiding insufficient heating in the surface area due to insufficient embedment depth of the electrode 300. At the same time, it increases the contact area between the electrode 300 and the concrete, improves the heat conduction efficiency, and keeps the overall temperature change of the guide wall 100 synchronized with that of the wall 10, effectively coordinating the deformation behavior between the two.

[0068] In some specific embodiments of the present invention, in S3, the guide wall 100 includes a first segment 110 and a second segment 120. The first segment 110 is disposed between the wall 10 and the base plate 20, extending along the extension direction of the wall 10 to connect with the base plate 20. A plurality of electrodes 300 are uniformly distributed inside the first segment 110. The second segment 120 is disposed on the first segment 110, protruding from the surface of the wall 10 and connecting with the base plate 20. At least a portion of the cross-sectional area of ​​the second segment 120 gradually decreases in the direction away from the base plate 20 to reduce the shrinkage difference between the guide wall 100 and the wall 10 due to temperature difference, thereby suppressing temperature cracks.

[0069] It should be further explained that the first section 110, as the main heat conduction area, is heated by uniformly distributed electrodes 300 so that the overall temperature field changes synchronously with the wall 10. The second section 120 adopts a tapered cross-section design, which gradually releases temperature deformation by changing the geometric shape. Its cross-sectional area decreases along the height direction to form a flexible transition zone, which effectively reduces the constraint between the guide wall 100 and the wall 10, so that the shrinkage difference caused by the temperature difference between the two is naturally resolved. This reduces the phenomenon of temperature stress concentration from the root and improves the durability and waterproof performance of the ultra-long concrete structure.

[0070] like Figure 2 and Figure 3 As shown, in this specific embodiment, the cross-section of the first segment 110 is rectangular and matches the cross-section of the wall 10. The cross-section of the second segment 120 is composed of a trapezoid and a rectangle stacked on top of each other. The lower side of the trapezoid matches the upper side of the rectangle to form a flexible transition zone in which the cross-sectional area of ​​part of the second segment 120 decreases along the height direction.

[0071] In some specific embodiments of the present invention, in step S3, multiple first temperature sensors 200 are uniformly arranged horizontally along a straight line where the geometric center of the guide wall 100 is located. It should be noted that since the geometric center line is the most representative location of the temperature field distribution of the guide wall 100, and is far from boundary thermal interference, arranging sensors here can obtain the most stable temperature data, avoiding measurement deviations caused by proximity to surfaces or edges. The uniformly distributed sensor network can comprehensively capture the temperature gradient changes along the length of the guide wall 100, providing an accurate basis for the dynamic control of the electrode 300 heating system, ensuring that the temperature of each segment of the guide wall 100 changes synchronously with the corresponding area of ​​the wall 10.

[0072] In some specific embodiments of the present invention, in S3, each electrode 300 has threads on its surface, which are configured to make the connection between the electrode 300 and the concrete tighter. It should be noted that the electrode 300 can be made of stainless steel, low-carbon steel, copper, etc. The electrode 300 is pre-embedded in the conductive concrete through pre-drilled holes or has threads on its surface, making the connection with the concrete more secure and tighter. Specifically, the mechanical interlocking principle is used to enhance the interfacial bonding strength between the electrode 300 and the conductive concrete, forming a multi-directional mechanical interlocking effect. When the concrete hardens and shrinks, the threads effectively resist interfacial slippage caused by temperature cycling or shrinkage deformation, ensuring the positional stability of the electrode 300 under long-term thermal expansion and contraction, and avoiding problems such as poor local contact or increased thermal resistance caused by loosening of the electrode 300.

[0073] In some specific embodiments of the present invention, in S4, the second temperature sensor 400 includes a first temperature sensing unit 410 and a second temperature sensing unit 420. A plurality of first temperature sensing units 410 are evenly arranged in the horizontal direction on the straight line where the geometric center of the wall 10 is located, and a plurality of second temperature sensing units 420 are evenly arranged in the horizontal direction on the surface of the wall 10. The first temperature sensing unit 410 and the second temperature sensing unit 420 cooperate to monitor the temperature difference between the inner and outer surfaces of the wall 10.

[0074] like Figure 2 and Figure 3 As shown, the first temperature sensing unit 410 accurately captures the hydration heat temperature rise process in the core area of ​​the concrete, while the second temperature sensing unit 420 records the temperature changes caused by heat exchange with the environment in real time. The collaborative monitoring of the two can accurately calculate the key parameter of the inner surface temperature difference and completely restore the distribution characteristics of the temperature field of the wall 10 section. This provides a comprehensive data basis for judging the development trend of temperature stress and the curing status of the concrete of the wall 10, enabling the control system to dynamically adjust the heating strategy of the guide wall 100 according to the inner surface temperature difference, achieve precise temperature deformation coordination, and significantly improve the reliability of crack control in ultra-long concrete structures.

[0075] In some specific embodiments of the present invention, in S4, before pouring ordinary concrete to the top elevation of the wall 10, the following steps are also included: curing the base plate 20 and the guide wall 100; after completing the curing of the base plate 20 and the guide wall 100, the guide wall 100 is roughened.

[0076] Specifically, the curing process allows the concrete of the base slab 20 and guide wall 100 to reach sufficient strength and complete initial shrinkage. The subsequent roughening process creates a uniformly rough interface on the surface of the guide wall 100, removing the weakened surface laitance layer and significantly increasing the contact surface area, providing an ideal bonding substrate for the newly poured wall 10 concrete. Simultaneously, the excellent interfacial bonding ensures the effective transfer of temperature stress between the guide wall 100 and the wall 10, allowing the temperature field generated by the electrode 300 to completely cover the entire structural system, thus achieving a dual guarantee of crack prevention and structural safety.

[0077] In some specific embodiments of the present invention, in S5, the power-on parameters of the real-time monitoring and adjustment electrode 300 based on the first temperature sensor 200 and the second temperature sensor 400 include: obtaining the temperature change curve of the concrete of the wall 10 according to the real-time monitoring data of the second temperature sensor 400; determining whether the concrete has reached the final setting state according to the concrete mix ratio and the on-site concrete condition; monitoring the center temperature of the guide wall 100 and the center temperature of the wall 10 in real time through the first temperature sensor 200 and the second temperature sensor 400; when the concrete of the wall 10 reaches the final setting state, dynamically adjusting the output of the power supply 320 to keep the temperature difference between the guide wall 100 and the center of the wall 10 within ±10℃; when the temperature of the concrete of the wall 10 reaches the peak, controlling the cooling rate of the guide wall 100 to be synchronized with the cooling rate of the wall 10; when the temperatures of both the wall 10 and the guide wall 100 drop to the ambient temperature, stopping the power supply and transferring the wall 10 and the guide wall 100 to routine curing.

[0078] A dynamic control mechanism based on the concrete hydration process was constructed using real-time monitoring data from the first temperature sensor 200 and the second temperature sensor 400. This mechanism deeply integrates concrete material characteristics, temperature development patterns, and active heating technology. Based on the characteristics of three stages—final setting state determination, peak temperature identification, and cooling rate matching—the heating parameters of the electrode 300 are precisely controlled. Closed-loop control is formed through feedback from the first temperature sensor 200 and the second temperature sensor 400, achieving a high degree of coordination between the deformation of the guide wall 100 and the wall 10. This ensures that the temperature stress is always within a safe threshold, significantly improving construction economy while guaranteeing project quality, and forming a scientific and reliable crack prevention system.

[0079] The following two specific embodiments illustrate this wall crack control method based on temperature-coordinated deformation.

[0080] Example 1:

[0081] S1: Obtain conductive materials, set the mix proportion of conductive concrete based on design requirements and construction specifications, and determine the resistivity and specific heat capacity of conductive concrete after the preset curing period through experiments.

[0082] The mix proportion of conductive concrete was designed according to the design documents and construction requirements. The concrete strength grade was obtained as C30. Steel fiber was used as the conductive material, and the volume fraction of steel fiber was designed to be 1%. The specific mix proportion of conductive concrete is shown in Table 1 below.

[0083] Table 1. Mix proportions of conductive concrete (kg / m³) 3

[0084] 224 96 1206 790 3.2 131 73

[0085] S2: Calculate the resistance between electrodes 300 based on resistivity, calculate the heat required for the conductive concrete to heat up based on specific heat capacity, and obtain the electrode spacing based on the resistance and the heat required for the conductive concrete to heat up.

[0086] The tests yielded the following results for the conductive concrete after 28 days: resistivity ρ = 250 Ω·m, specific heat capacity c = 950 J / (kg·℃), and bulk density P = 2520 kg / m³. 3 On-site, a 60V power supply of 320V was used to power the concrete. After 27 hours of power supply, the concrete temperature increased by 15℃. Substituting into the formula, we can get l = 20m.

[0087] It should be noted that the resistivity of conductive concrete can be obtained through the four-electrode 300 method and the two-electrode 300 method, and the specific heat capacity of conductive concrete can be obtained through the mixed calorimetry or differential scanning calorimetry. These are conventional technical methods, and their working principles and structures will not be further elaborated here.

[0088] S3: Embed the first temperature sensor 200 in the preset pouring area of ​​the guide wall 100, embed the electrode 300 in the preset pouring area of ​​the guide wall 100 according to the electrode spacing, pour the base plate 20 with ordinary concrete to the bottom elevation of the guide wall 100, and pour the guide wall 100 with conductive concrete to the bottom elevation of the wall 10.

[0089] Stainless steel rods are selected as electrodes 300. The electrodes 300 are arranged at equal intervals on the guide wall 100 according to the calculated spacing, ensuring that the electrodes 300 do not contact the reinforcing steel bars of the wall 10 and the base plate 20, and that the bottom of the electrodes 300 is embedded in the guide wall 100 to a depth equal to the height of the guide wall 100. Specifically, such as Figure 2 and Figure 3 As shown, there are three electrodes 300, two of which are connected to the positive terminal of the power supply 320, and the other electrode 300 is connected to the negative terminal of the power supply 320. The two electrodes 300 connected to the positive terminal of the power supply 320 are respectively located at the left and right ends of the guide wall 100, and the electrode 300 connected to the negative terminal of the power supply 320 is located between the other two electrodes 300.

[0090] Before the concrete of the base slab 20 is poured, two first temperature sensors 200 are arranged at the geometric center of the guide wall 100 to monitor the temperature change of the guide wall 100. Ordinary concrete is used to pour the base slab 20. When the concrete reaches the bottom elevation of the guide wall 100, it is replaced with conductive concrete for pouring the guide wall 100. The base slab 20 and the guide wall 100 are cured until the concrete strength reaches more than 70% of the design strength. Then the guide wall 100 is roughened.

[0091] S4: Embed the second temperature sensor 400 in the pre-casting area of ​​the wall 10, and use ordinary concrete to cast the wall 10 to the top elevation of the wall 10.

[0092] Before the concrete of the wall 10 is poured, two first temperature sensing units 410 are evenly arranged at the geometric center of the wall 10, and two second temperature sensors 400 are arranged on the side surface of the wall 10 to monitor the temperature change inside the wall 10 and the temperature difference between the inner and outer surfaces. Ordinary concrete is used to pour the wall 10.

[0093] S5: Adjust the power supply parameters of electrode 300 based on the real-time monitoring results of the first temperature sensor 200 and the second temperature sensor 400 so that the temperature change rate of the guide wall 100 is synchronized with the temperature change rate of the wall 10. When the temperature of the wall 10 drops to the ambient temperature, disconnect the power supply 320 of electrode 300.

[0094] Specifically, the temperature change curve of the concrete in wall 10 is obtained based on the real-time monitoring data of the second temperature sensor 400. Based on the final setting time data in the mix proportion report and the on-site concrete condition, it is determined whether the concrete has reached the final setting state. The center temperature of the guide wall 100 and the center temperature of wall 10 are monitored in real time by the first temperature sensor 200 and the second temperature sensor 400. When the concrete in wall 10 reaches the final setting state, the output of the power supply 320 is dynamically adjusted to keep the temperature difference between the center of the guide wall 100 and the center of wall 10 within ±10℃. When the temperature of the concrete in wall 10 reaches its peak, the cooling rate of the guide wall 100 is controlled to be synchronized with the cooling rate of wall 10. When the temperatures of both wall 10 and guide wall 100 drop to the ambient temperature, the power supply is stopped and wall 10 and guide wall 100 are transferred to routine curing.

[0095] Example 2:

[0096] S1: Obtain conductive materials, set the mix proportion of conductive concrete based on design requirements and construction specifications, and determine the resistivity and specific heat capacity of conductive concrete after the preset curing period through experiments.

[0097] The mix proportion of conductive concrete was designed according to the design documents and construction requirements. The concrete strength grade was obtained as C40. Carbon fiber was used as the conductive material, and the volumetric content of carbon fiber was designed to be 1.2%. The mix proportion of conductive concrete is shown in Table 2 below.

[0098] Table 2. Mix proportions of conductive concrete (kg / m³) 3

[0099] 210 80 110 1085 723 4.8 152 36

[0100] S2: Calculate the resistance between electrodes 300 based on resistivity, calculate the heat required for the conductive concrete to heat up based on specific heat capacity, and obtain the electrode spacing based on the resistance and the heat required for the conductive concrete to heat up.

[0101] The experimental results showed that the resistivity of the conductive concrete after 28 days was ρ = 25 Ω·m, the specific heat capacity was c = 980 J / (kg·℃), and the bulk density was P = 2450 kg / m³. 3 On-site, a 36V power supply of 320V was used to power the concrete. After 18 hours of power supply, the concrete temperature increased by 20℃. Substituting into the formula, we can get l = 26m.

[0102] It should be noted that the resistivity of conductive concrete can be obtained through the four-electrode 300 method and the two-electrode 300 method, and the specific heat capacity of conductive concrete can be obtained through the mixed calorimetry or differential scanning calorimetry. These are conventional technical methods, and their working principles and structures will not be further elaborated here.

[0103] S3: Embed the first temperature sensor 200 in the preset pouring area of ​​the guide wall 100, embed the electrode 300 in the preset pouring area of ​​the guide wall 100 according to the electrode spacing, pour the base plate 20 with ordinary concrete to the bottom elevation of the guide wall 100, and pour the guide wall 100 with conductive concrete to the bottom elevation of the wall 10.

[0104] Graphite rods are selected as electrodes 300. The electrodes 300 are arranged at equal intervals on the guide wall 100 according to the calculated spacing, ensuring that the electrodes 300 do not contact the reinforcing steel bars of the wall 10 and the base plate 20, and that the bottom of the electrodes 300 is embedded in the guide wall 100 to a depth equal to the height of the guide wall 100.

[0105] Before pouring the concrete for the base slab 20, two first temperature sensors 200 are arranged at the geometric center of the guide wall 100 to monitor the temperature change of the guide wall 100. The base slab 20 is poured with ordinary concrete. When the concrete reaches the bottom elevation of the guide wall 100, it is replaced with conductive concrete. The base slab 20 and the guide wall 100 are cured until the concrete strength reaches more than 70% of the design strength. Then, the guide wall 100 is roughened.

[0106] S4: Embed the second temperature sensor 400 in the pre-casting area of ​​the wall 10, and use ordinary concrete to cast the wall 10 to the top elevation of the wall 10.

[0107] Before the concrete of the wall 10 is poured, two first temperature sensing units 410 are evenly arranged at the geometric center of the wall 10, and two second temperature sensors 400 are arranged on the side surface of the wall 10 to monitor the temperature change inside the wall 10 and the temperature difference between the inner and outer surfaces. Ordinary concrete is used to pour the wall 10.

[0108] S5: Adjust the power supply parameters of electrode 300 based on the real-time monitoring results of the first temperature sensor 200 and the second temperature sensor 400 so that the temperature change rate of the guide wall 100 is synchronized with the temperature change rate of the wall 10. When the temperature of the wall 10 drops to the ambient temperature, disconnect the power supply 320 of electrode 300.

[0109] Specifically, the temperature change curve of the concrete in wall 10 is obtained based on the real-time monitoring data of the second temperature sensor 400. Based on the final setting time data in the mix proportion report and the on-site concrete condition, it is determined whether the concrete has reached the final setting state. The center temperature of the guide wall 100 and the center temperature of wall 10 are monitored in real time by the first temperature sensor 200 and the second temperature sensor 400. When the concrete in wall 10 reaches the final setting state, the output of the power supply 320 is dynamically adjusted to keep the temperature difference between the center of the guide wall 100 and the center of wall 10 within ±10℃. When the temperature of the concrete in wall 10 reaches its peak, the cooling rate of the guide wall 100 is controlled to be synchronized with the cooling rate of wall 10. When the temperatures of both wall 10 and guide wall 100 drop to the ambient temperature, the power supply is stopped and wall 10 and guide wall 100 are transferred to routine curing.

[0110] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for controlling wall cracking based on temperature-coordinated deformation, characterized in that, In the junction area of ​​the wall bottom of an ultra-long concrete structure, a guide wall (100) is provided between the wall (10) and the base plate (20). The wall (10) is connected to the base plate (20) through the guide wall (100). Multiple electrodes (300) and multiple first temperature sensors (200) are embedded in the guide wall (100). The multiple electrodes (300) are evenly distributed in the guide wall (100). The multiple electrodes (300) are all connected to the power supply (320) through wires (310). The multiple first temperature sensors (200) are evenly distributed in the guide wall (100). The first temperature sensors (200) are used to monitor the temperature change inside the guide wall (100). Multiple second temperature sensors (400) are embedded in the wall (10). The multiple second temperature sensors (400) are evenly distributed in the wall (10). The second temperature sensors (400) are used to monitor the temperature change inside the wall (10). Wall crack control methods include: S1: Obtain conductive materials, set the mix proportion of conductive concrete based on design requirements and construction specifications, and determine the resistivity and specific heat capacity of conductive concrete after the preset curing period through experiments; S2: Calculate the resistance between electrodes (300) based on resistivity, calculate the heat required for the conductive concrete to heat up based on specific heat capacity, and obtain the electrode spacing based on resistance and the heat required for the conductive concrete to heat up. S3: The first temperature sensor (200) is pre-embedded in the pre-casting area of ​​the guide wall (100), and the electrode (300) is pre-embedded in the pre-casting area of ​​the guide wall (100) according to the electrode spacing. The bottom plate (20) is poured with ordinary concrete to the bottom elevation of the guide wall (100), and the guide wall (100) is poured with conductive concrete to the bottom elevation of the wall (10). S4: Embed a second temperature sensor (400) in the pre-casting area of ​​the wall (10), and use ordinary concrete to cast the wall (10) to the top elevation of the wall (10); S5: Adjust the power supply parameters of electrode (300) based on the real-time monitoring results of the first temperature sensor (200) and the second temperature sensor (400) so that the temperature change rate of the guide wall (100) is synchronized with the temperature change rate of the wall (10). When the temperature of the wall (10) drops to the ambient temperature, disconnect the power supply (320) of electrode (300).

2. The wall crack control method based on temperature-coordinated deformation according to claim 1, characterized in that, In S2, the electrode spacing is obtained based on the heat required for the conductive concrete to heat up, and the electrode spacing is calculated using the following formula: In the formula, The distance between the electrodes. The voltage across the conductor wall. The power supply time for the guide wall. The resistivity of the conductive wall, To guide the wall's density, To guide the rise in temperature of the guide wall, This refers to the specific heat capacity of the conductive wall.

3. The wall crack control method based on temperature-coordinated deformation according to claim 1, characterized in that, In S3, the pre-embedded electrode (300) is insulated from the structural steel bars of the base plate (20) and the structural steel bars of the guide wall (100).

4. The wall crack control method based on temperature-coordinated deformation according to claim 1, characterized in that, In S3, the depth to which the bottom of the electrode (300) is embedded in the guide wall (100) is at least [amount missing] of the thickness of the guide wall (100). .

5. The wall crack control method based on temperature-coordinated deformation according to claim 1, characterized in that, In S3, the guide wall (100) includes: The first section (110) is located between the wall (10) and the base plate (20). The first section (110) extends along the extension direction of the wall (10) to connect with the base plate (20). Multiple electrodes (300) are evenly distributed inside the first section (110). The second section (120) is located on the first section (110). The second section (120) protrudes from the surface of the wall (10) and is connected to the base plate (20). At least part of the cross-sectional area of ​​the second section (120) gradually decreases in the direction away from the base plate (20) to reduce the shrinkage difference between the guide wall (100) and the wall (10) caused by the temperature difference, thereby suppressing temperature cracks.

6. The wall crack control method based on temperature-coordinated deformation according to claim 1, characterized in that, In S3, multiple first temperature sensors (200) are evenly arranged in the horizontal direction on the straight line where the geometric center of the guide wall (100) is located.

7. The wall crack control method based on temperature-coordinated deformation according to claim 1, characterized in that, In S3, each electrode (300) has threads on its surface, which are configured to make the connection between the electrode (300) and the concrete tighter.

8. The wall crack control method based on temperature-coordinated deformation according to claim 1, characterized in that, In S4, the second temperature sensor (400) includes a first temperature sensing unit (410) and a second temperature sensing unit (420). Multiple first temperature sensing units (410) are evenly arranged in the horizontal direction on the straight line where the geometric center of the wall (10) is located. Multiple second temperature sensing units (420) are evenly arranged in the horizontal direction on the surface of the wall (10). The first temperature sensing unit (410) and the second temperature sensing unit (420) cooperate to monitor the temperature difference between the inner and outer surfaces of the wall (10).

9. The wall crack control method based on temperature-coordinated deformation according to claim 1, characterized in that, In S4, before pouring ordinary concrete into the wall (10) to the top elevation of the wall (10), the following steps are also included: Maintain the base plate (20) and guide wall (100); After the base plate (20) and guide wall (100) have been cured, the guide wall (100) is roughened.

10. The wall crack control method based on temperature-coordinated deformation according to claim 1, characterized in that, In S5, the energizing parameters of the regulating electrode (300) monitored in real time based on the first temperature sensor (200) and the second temperature sensor (400) include: The temperature change curve of the wall (10) concrete is obtained based on the real-time monitoring data of the second temperature sensor (400), and the concrete mix ratio and the on-site concrete condition are used to determine whether the concrete has reached the final setting state. The center temperature of the guide wall (100) and the center temperature of the wall (10) are monitored in real time by the first temperature sensor (200) and the second temperature sensor (400). When the concrete of the wall (10) reaches the final setting state, the output of the power supply (320) is dynamically adjusted so that the temperature difference between the center of the guide wall (100) and the wall (10) is kept within ±10℃. When the concrete temperature of the wall (10) reaches its peak, the cooling rate of the guide wall (100) is controlled to be synchronized with the cooling rate of the wall (10). When the temperature of both the wall (10) and the guide wall (100) drops to the ambient temperature, the power supply is stopped and the wall (10) and the guide wall (100) are put into routine maintenance.

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