Wall crack control method based on temperature collaborative deformation

Abstract

The invention discloses a wall crack control method based on temperature synergistic deformation, and belongs to the technical field of concrete construction.The wall crack control method based on temperature synergistic deformation comprises the steps that a conductive material is obtained, the mix proportion of conductive concrete is set, and the resistivity and specific heat capacity of the conductive concrete are measured; resistance between the electrodes is obtained, and the electrode distance is obtained through calculation; a first temperature sensor and an electrode are pre-buried in the guide wall, a bottom plate is poured through common concrete, and the guide wall is poured through conductive concrete; a second temperature sensor is pre-buried in the wall body, and the wall body is poured through common concrete; power-on parameters of the electrode are adjusted, so that the temperature change rate of the guide wall is synchronous with that of the wall body, and when the temperature of the wall body is reduced to the environment temperature, the electrode power supply is cut off. Temperature deformation of the guide wall and the wall body can be dynamically coordinated, shrinkage difference caused by temperature difference is eliminated, then constraint stress of the interface of the wall body and the bottom plate is reduced, cracks of an ultra-long concrete structure are restrained, and the waterproofness and construction efficiency of the whole structure are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete construction, and in particular to a wall crack control method based on temperature coordinated deformation. Background Art

[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 layered and segmented pouring. The shrinkage and deformation of concrete poured at different times are not synchronized due to age differences, which significantly amplifies the shrinkage and deformation of concrete and the temperature difference deformation effect.

[0003] Specifically, the base plate of an ultra-long concrete structure is usually cast first and hardens early. When the wall concrete cast later shrinks, its deformation will be strongly constrained by the base plate, resulting in significant shrinkage stress concentration in the junction area between the wall and the bottom, which in turn causes tensile damage to the concrete components and eventually forms irregular cracks, seriously affecting the durability and bearing capacity of the concrete structure. Summary of the Invention

[0004] The present invention aims to address at least one of the technical problems existing in the prior art. To this end, it proposes a wall crack control method based on temperature-coordinated deformation. This method can control the concrete temperature to coordinate the volumetric deformation of the base plate and wall, thereby reducing wall shrinkage stress and the risk of cracking.

[0005] A wall crack control method based on temperature coordinated deformation according to an embodiment of the present invention 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, the wall being connected to the bottom plate via the guide wall, a plurality of electrodes and a plurality of first temperature sensors are embedded in the guide wall, the plurality of electrodes are evenly distributed in the guide wall, the plurality of electrodes are connected to a power supply via wires, the plurality of first temperature sensors are evenly distributed in the guide wall, the first temperature sensors are used to monitor temperature changes within the guide wall, and a plurality of second temperature sensors are embedded in the wall, the plurality of second temperature sensors are evenly distributed in the wall, the second temperature sensors are used to monitor temperature changes within the wall; Wall crack control methods include: S1: Obtain conductive materials, set the conductive concrete mix ratio based on design requirements and construction specifications, and test the resistivity and specific heat capacity of the conductive concrete after a preset curing period. S2: Obtain the resistance between electrodes based on resistivity calculation, obtain the heat required to heat the conductive concrete based on specific heat capacity calculation, and obtain the electrode spacing based on the resistance and the heat required to heat the conductive concrete. S3: Pre-embed a first temperature sensor in a preset casting area of the guide wall, pre-embed electrodes in the preset casting area of the guide wall according to the electrode spacing, cast a base plate to the bottom elevation of the guide wall using ordinary concrete, and cast the guide wall to the bottom elevation using conductive concrete; S4: Pre-embed the second temperature sensor in the preset pouring area of the wall, and pour the wall to the top elevation using ordinary concrete; S5: Based on the real-time monitoring results of the first temperature sensor and the second temperature sensor, the power supply parameters of the electrode are adjusted to synchronize the temperature change rate of the guide wall with the temperature change rate of the wall. When the wall temperature drops to the ambient temperature, the electrode power supply is disconnected.

[0006] The wall crack control method based on temperature coordinated deformation according to the embodiment of the present invention has at least the following beneficial effects: utilizing the electrothermal characteristics of conductive concrete, the guide wall is used as an active heat source, and the internal temperature of the guide wall is regulated by the Joule heat generated by the electrification of the electrode. At the same time, combined with the multi-stage temperature sensors arranged on the guide wall and the wall, a closed-loop feedback control system is constructed to dynamically adjust the heating power and the power-on time, so that the temperature deformation of the guide wall and the wall is dynamically coordinated, eliminating the shrinkage difference caused by the temperature difference, thereby significantly reducing the constraint stress at the interface between the wall and the bottom plate, and suppressing the horizontal through cracks in the ultra-long concrete structure, solving the problem that traditional passive maintenance is difficult to cope with complex temperature change environments, while reducing the use of construction joints and post-pouring strips, and improving the overall structural waterproofness and construction efficiency.

[0007] According to some embodiments of the present invention, in S2, the electrode spacing is obtained based on the heat required to heat the conductive concrete. The electrode spacing is calculated using the following formula:

[0008] Where, is the electrode spacing, is the voltage across the conductor wall, is the time when the guide wall is energized, is the resistivity of the guide wall, is the bulk density of the guide wall, is the temperature rise of the guide wall, is the specific heat capacity of the guide wall.

[0009] According to some embodiments of the present invention, in S3, the embedded electrodes are insulated from the bottom plate structural steel bars and the guide wall structural steel bars.

[0010] According to some embodiments of the present invention, in S3, the depth of the bottom of the electrode buried in the guide wall is at least 1 / 3 of the thickness of the guide wall. .

[0011] According to some embodiments of the present invention, in S3, the guide wall includes: a first section, the first section is arranged between the wall and the bottom plate, the first section extends along the extension direction of the wall to be connected to the bottom plate, and a plurality of electrodes are evenly distributed inside the first section; a second section, the second section is arranged on the first section, the second section protrudes from the wall surface and is connected to the bottom plate, and the cross-sectional area of at least part of the second section gradually decreases in the direction away from the bottom plate, so as to reduce the shrinkage difference between the guide wall and the wall due to the temperature difference, thereby suppressing temperature cracks.

[0012] According to some embodiments of the present invention, in S3, a plurality of first temperature sensors are evenly arranged in a horizontal direction on a straight line where the geometric center of the guide wall is located.

[0013] According to some embodiments of the present invention, in S3 , a surface of each electrode is provided with a thread, and the thread is configured to make the connection between the electrode and the concrete tighter.

[0014] 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 evenly 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 evenly arranged in the horizontal direction on the surface of the wall, and the first temperature sensing unit cooperates with the second temperature sensing unit to monitor the temperature difference between the inner and outer surfaces of the wall.

[0015] According to some embodiments of the present invention, in S4, before pouring the wall to the top elevation of the wall with ordinary concrete, the following steps are also included: curing the bottom plate and the guide wall; after completing the curing of the bottom plate and the guide wall, roughening the guide wall.

[0016] According to some embodiments of the present invention, in S5, adjusting the electrode power parameters based on real-time monitoring of the first temperature sensor and the second temperature sensor includes: obtaining the temperature change curve of the wall concrete according to the real-time monitoring data of the second temperature sensor, and judging whether the concrete has reached the final setting state according to the concrete mix ratio and the on-site concrete state; monitoring the center temperature of the guide wall and the center temperature of the wall in real time through the first temperature sensor and the second temperature sensor, and when the wall concrete reaches the final setting state, dynamically adjusting the power output to keep the center temperature difference between the guide wall and the wall within ±10°C; when the wall concrete temperature reaches the peak, controlling the cooling rate of the guide wall to be synchronized with the cooling rate of the wall; when the temperatures of the wall and the guide wall both drop to the ambient temperature, stopping the power supply and switching the wall and the guide wall to conventional maintenance.

[0017] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which: Figure 1 Schematic diagram of the process of the wall crack control method based on temperature coordinated deformation in this specific embodiment; Figure 2 A schematic structural diagram of the guide wall in the wall crack control method based on temperature coordinated deformation in this specific embodiment; Figure 3 for Figure 2 Schematic cross-section diagram in .

[0019] Reference numerals: Wall 10, bottom plate 20; Guide wall 100, first section 110, second section 120; a first temperature sensor 200; Electrode 300, wire 310, power supply 320; The second temperature sensor 400 , the first temperature sensing unit 410 , and the second temperature sensing unit 420 . DETAILED DESCRIPTION

[0020] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0021] In the description of the present invention, "several" means one or more, "multiple" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, and "above," "below," and "within" are understood to include the number itself. The use of terms such as "first" and "second" is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0022] In the description of the present invention, unless otherwise clearly defined, words such as “setting”, “installation” and “connection” should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above words in the present invention based on the specific content of the technical solution.

[0023] Please refer to Figures 1 to 3This embodiment discloses a wall crack control method based on temperature coordinated deformation, which is 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 bottom plate 20. The wall 10 is connected to the bottom plate 20 via the guide wall 100. A plurality of electrodes 300 and a plurality of first temperature sensors 200 are embedded in the guide wall 100. The plurality of electrodes 300 are evenly distributed in the guide wall 100. The plurality of electrodes 300 are connected to a power source 320 via wires 310. The plurality of first temperature sensors 200 are evenly distributed in the guide wall 100. The first temperature sensors 200 are used to monitor temperature changes within the guide wall 100. A plurality of second temperature sensors 400 are embedded in the wall 10. The plurality of second temperature sensors 400 are evenly distributed in the wall 10. The second temperature sensors 400 are used to monitor temperature changes within the wall 10. Wall crack control methods include: S1: Obtain conductive materials, set the conductive concrete mix ratio based on design requirements and construction specifications, and test the resistivity and specific heat capacity of the conductive concrete after a preset curing period. S2: Obtain the resistance between the electrodes 300 based on the resistivity calculation, obtain the amount of heat required to heat the conductive concrete based on the specific heat capacity calculation, and obtain the electrode spacing based on the resistance and the amount of heat required to heat the conductive concrete; S3: Pre-embed the first temperature sensor 200 in the preset casting area of the guide wall 100, pre-embed the electrode 300 in the preset casting area of the guide wall 100 according to the electrode spacing, use ordinary concrete to cast the bottom plate 20 to the bottom elevation of the guide wall 100, and use conductive concrete to cast the guide wall 100 to the bottom elevation of the wall body 10; S4: pre-embed the second temperature sensor 400 in the preset pouring area of the wall 10, and pour the wall 10 to the top elevation of the wall 10 using ordinary concrete; S5: Based on the real-time monitoring results of the first temperature sensor 200 and the second temperature sensor 400, the power parameters of the electrode 300 are adjusted to synchronize the temperature change rate of the guide wall 100 with the temperature change rate of the wall 10. When the temperature of the wall 10 drops to the ambient temperature, the power supply 320 of the electrode 300 is disconnected.

[0024] By utilizing the electrothermal properties of conductive concrete, the guide wall 100 is used as an active heat source, and the internal temperature of the guide wall 100 is regulated by the Joule heat generated by the electrification of the electrode 300. At the same time, combined with the multi-stage temperature sensors arranged on the guide wall 100 and the wall 10, a closed-loop feedback control system is constructed to dynamically adjust the heating power and the power-on time, so that the temperature deformation of the guide wall 100 and the wall 10 is dynamically coordinated, eliminating the shrinkage difference caused by the temperature difference, thereby significantly reducing the constraint stress at the interface between the wall 10 and the base plate 20, and suppressing the horizontal through cracks in the ultra-long concrete structure, solving the problem that traditional passive maintenance is difficult to cope with complex temperature change environments, while reducing the use of construction joints and post-pouring strips, and improving the waterproofness and construction efficiency of the overall structure.

[0025] In some specific embodiments of the present invention, in S2, the electrode spacing is obtained based on the heat required to heat the conductive concrete. The electrode spacing is calculated using the following formula:

[0026] Where, is the electrode spacing, is the voltage across the conductor wall, is the time when the guide wall is energized, is the resistivity of the guide wall, is the bulk density of the guide wall, is the temperature rise of the guide wall, is the specific heat capacity of the guide wall.

[0027] It should be noted that the calculation formula for the electrode spacing is derived from the following steps: Conductive concrete is tested and the resistivity of the conductive concrete is obtained. , the conductive concrete resistance between the two electrodes 300 is calculated using the following formula:

[0028] Where, is the resistance of conductive concrete Ω, is the resistivity of conductive concrete Ω·m, is the distance m between the two electrodes, is the cross-sectional area of the guide wall m 2 ; According to the specific heat capacity of conductive concrete obtained from the experiment , the heat required to increase the temperature T of the conductive concrete between the two electrodes 300 is calculated using the following formula:

[0029] Where, is the heat J, is the volume of conductive concrete m 3 , is the bulk density of conductive concrete kg / m 3 , is the rising temperature ℃, is the specific heat capacity of conductive concrete J / kg·℃; Considering the electrode 300 and the conductive concrete as a pure resistance circuit, according to Joule's law, we can obtain:

[0030] Where, is the heat J generated by the current passing through the conductive concrete, U is the voltage V across the conductive concrete, and t is the power-on time s; Assuming that the heat required for the conductive concrete to rise in temperature by T is provided by electrical energy conversion, the following formula is satisfied:

[0031] Right now,

[0032] Therefore, the spacing between the electrodes 300 is:

[0033] Where, is the electrode spacing, is the voltage across the conductor wall, is the time when the guide wall is energized, is the resistivity of the guide wall, is the bulk density of the guide wall, is the temperature rise of the guide wall, is the specific heat capacity of the guide wall.

[0034] In some specific embodiments of the present invention, in S3, the pre-buried electrodes 300 are insulated from the structural steel bars of the base plate 20 and the guide wall 100 to prevent the current from short-circuiting or shunting through the steel network when the electrodes 300 are energized, thereby ensuring that the electrical energy is concentratedly converted into Joule heat in the concrete of the guide wall 100. It should be noted that the conductive path between the electrodes 300 and the steel bars can be cut off by physical isolation. Specifically, for example, by applying an insulating coating or providing a plastic casing on the steel bars, the current flows in the conductive concrete strictly according to the designed path, ensuring the stability and controllability of the heating efficiency, while preventing stray current from causing electrochemical corrosion to the structural steel bars, and maintaining the durability of the concrete structure.

[0035] In some specific embodiments of the present invention, in S3, the bottom of the electrode 300 is buried in the guide wall 100 to a depth of at least 1 / 3 of the thickness of the guide wall 100. , ensuring that the heat generated by the electrode 300 fully covers the entire cross-section of the guide wall 100, forming a uniform and stable temperature field. Specifically, by deeply burying the electrode 300 at the bottom of the guide wall 100, the current path can penetrate the entire thickness of the concrete, preventing insufficient heating of the surface area due to insufficient burial depth of the electrode 300. At the same time, the contact area between the electrode 300 and the concrete is increased, improving heat conduction efficiency, ensuring that the overall temperature changes of the guide wall 100 are synchronized with the wall 10, effectively coordinating the deformation behavior of the two.

[0036] In some specific embodiments of the present invention, in S3, the guide wall 100 includes a first section 110 and a second section 120, wherein the first section 110 is disposed between the wall 10 and the bottom plate 20, and extends along the extension direction of the wall 10 until it is connected to the bottom plate 20, and the plurality of electrodes 300 are evenly distributed within the first section 110. The second section 120 is disposed on the first section 110, protruding from the surface of the wall 10 and connected to the bottom plate 20, and the cross-sectional area of at least a portion of the second section 120 gradually decreases in a direction away from the bottom plate 20, thereby reducing the differential shrinkage between the guide wall 100 and the wall 10 due to the temperature difference, thereby suppressing temperature cracks.

[0037] It should be further explained that the first section 110 serves as the main heat conduction area. The heating is performed by the evenly 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 the 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 between the two due to the temperature difference is naturally eliminated, thereby reducing the temperature stress concentration phenomenon from the root and improving the durability and waterproof performance of the ultra-long concrete structure.

[0038] like Figure 2 and Figure 3 As shown, in this specific embodiment, the cross-section of the first section 110 is a rectangle that matches the cross-section of the wall 10, and the cross-section of the second section 120 is composed of a trapezoid and a rectangle stacked up and down, wherein 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 section 120 decreases along the height direction.

[0039] In some specific embodiments of the present invention, in step S3, multiple first temperature sensors 200 are evenly distributed horizontally along a straight line at the geometric center of the guide wall 100. It should be noted that because the geometric centerline is the most representative location for the temperature field distribution of the guide wall 100 and is far away from boundary thermal interference, placing sensors there can obtain the most stable temperature data and avoid measurement deviations caused by proximity to surfaces or edges. This evenly distributed sensor network can fully capture 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 and ensuring that the temperature of each section of the guide wall 100 changes synchronously with the corresponding area of the wall 10.

[0040] In some specific embodiments of the present invention, in S3, the surface of each electrode 300 is provided with a thread, and the thread is configured to make the connection between the electrode 300 and the concrete tighter. It should be noted that the material of the electrode 300 can be stainless steel, low carbon steel and copper, etc. The electrode 300 is pre-buried in the conductive concrete with reserved holes or has threads on the surface, so that the connection with the concrete is more firm and tight. Specifically, the mechanical bite principle is used to enhance the interface bonding strength between the electrode 300 and the conductive concrete, forming a multi-directional mechanical interlocking effect. When the concrete hardens and shrinks, the thread effectively resists the interface slip caused by temperature cycling or shrinkage deformation, ensuring the position fixity of the electrode 300 under long-term thermal expansion and contraction, and avoiding the problem of local poor contact or increased thermal resistance caused by loosening of the electrode 300.

[0041] 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, multiple first temperature sensing units 410 are evenly arranged in the horizontal direction on a straight line where the geometric center of the wall 10 is located, and multiple second temperature sensing units 420 are evenly arranged in the horizontal direction on the surface of the wall 10, and the first temperature sensing unit 410 cooperates with the second temperature sensing unit 420 to monitor the temperature difference between the inner and outer surfaces of the wall 10.

[0042] 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 coordinated monitoring of the two can accurately calculate the key parameter of the internal-surface temperature difference and completely restore the distribution characteristics of the temperature field in the cross section of the wall 10. This provides a comprehensive data basis for judging the development trend of temperature stress and the curing status of the concrete in the wall 10, enabling the control system to dynamically adjust the heating strategy of the guide wall 100 according to the internal-surface temperature difference, achieving precise temperature-deformation coordination and significantly improving the reliability of crack control in ultra-long concrete structures.

[0043] In some specific embodiments of the present invention, in S4, before ordinary concrete is used to cast the wall 10 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.

[0044] Specifically, the curing process ensures that the concrete of the base plate 20 and guide wall 100 reaches sufficient strength and completes initial shrinkage. The subsequent roughening process creates a uniformly roughened interface on the surface of the guide wall 100, removing the weakened laitance layer and significantly increasing the contact surface area, providing an ideal bonding surface for the newly poured concrete of the wall 10. Furthermore, this excellent interface ensures the effective transfer of thermal stress between the guide wall 100 and the wall 10, allowing the temperature field generated by the heating of the electrode 300 to fully cover the entire structural system, thereby achieving both crack prevention and structural safety.

[0045] In some specific embodiments of the present invention, in S5, adjusting the power supply parameters of the electrode 300 based on the real-time monitoring of the first temperature sensor 200 and the second temperature sensor 400 includes: 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, and judging whether the concrete has reached the final setting state according to the concrete mix ratio and the on-site concrete state; 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, and when the concrete of the wall 10 reaches the final setting state, dynamically adjusting the output of the power supply 320 so that the center temperature difference between the guide wall 100 and the wall 10 is maintained within ±10°C; 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 the wall 10 and the guide wall 100 both drop to the ambient temperature, stopping the power supply and switching the wall 10 and the guide wall 100 to conventional maintenance.

[0046] Based on the real-time monitoring data of the first temperature sensor 200 and the second temperature sensor 400, a dynamic control mechanism based on the concrete hydration process was constructed, which deeply integrated the concrete material properties, temperature development laws and active heating technology. According to the three-stage characteristics of final setting state determination, peak temperature identification and cooling rate matching, the heating parameters of the electrode 300 were precisely controlled. Through the feedback of the first temperature sensor 200 and the second temperature sensor 400, a closed-loop control was formed to achieve a high degree of coordination between the deformation of the guide wall 100 and the wall body 10, so that the temperature stress is always within the safety threshold. While ensuring the quality of the project, the construction economy is significantly improved, and a scientific and reliable crack prevention and control system is formed.

[0047] The wall crack control method based on temperature coordinated deformation is described below with reference to two specific embodiments.

[0048] Example 1: S1: Obtain conductive materials, set the conductive concrete mix ratio based on design requirements and construction specifications, and test the resistivity and specific heat capacity of the conductive concrete after a preset curing period.

[0049] The conductive concrete mix ratio is designed according to the design documents and construction requirements. The concrete strength grade is C30. Steel fiber is used as the conductive material, and the volume content of the steel fiber is designed to be 1%. The specific mix ratio of the conductive concrete is shown in Table 1 below.

[0050] Table 1 Conductive concrete mix ratio kg / m 3

[0051] S2: Obtain the resistance between the electrodes 300 based on the resistivity calculation, obtain the amount of heat required for heating the conductive concrete based on the specific heat capacity calculation, and obtain the electrode spacing based on the resistance and the amount of heat required for heating the conductive concrete.

[0052] The test results show that the resistivity of conductive concrete after 28 days is ρ = 250Ω∙m, the specific heat capacity is c = 950J / (kg·℃), and the bulk density is P = 2520kg / m 3 , a 60V power supply 320 is used on site for power supply. The concrete temperature rises by 15℃ after 27 hours of power supply. Substituting it into the formula, we can get l=20m.

[0053] It should be noted that the resistivity of conductive concrete can be obtained by the four-electrode 300 method and the two-electrode 300 method, and the specific heat capacity of conductive concrete can be obtained by hybrid calorimetry or differential scanning calorimetry. These are conventional technical means, and their working principles and structures will not be further described here.

[0054] S3: Pre-embed the first temperature sensor 200 in the preset casting area of the guide wall 100, pre-embed the electrode 300 in the preset casting area of the guide wall 100 according to the electrode spacing, use ordinary concrete to cast the bottom plate 20 to the bottom elevation of the guide wall 100, and use conductive concrete to cast the guide wall 100 to the bottom elevation of the wall 10.

[0055] Select stainless steel rods as electrodes 300, and arrange the electrodes 300 at equal intervals on the guide wall 100 according to the calculated electrode 300 spacing, and make sure that the electrodes 300 do not contact the steel bars of the wall 10 and the bottom plate 20, and make the bottom of the electrode 300 buried in the guide wall 100 reach the depth of the guide wall 100. Specifically, Figure 2 and Figure 3 As shown, there are three electrodes 300, two of which are connected to the positive pole of the power supply 320, and the other electrode 300 is connected to the negative pole of the power supply 320. The two electrodes 300 connected to the positive pole of the power supply 320 are respectively arranged at the left and right ends of the guide wall 100, and the electrode 300 connected to the negative pole of the power supply 320 is arranged between the other two electrodes 300.

[0056] Before pouring concrete for the base plate 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. Ordinary concrete is used to cast the base plate 20. When the concrete reaches the bottom elevation of the guide wall 100, conductive concrete is used to cast the guide wall 100. After the base plate 20 and the guide wall 100 are cured until the strength of the concrete reaches more than 70% of the design strength, the guide wall 100 is roughened.

[0057] S4: pre-embed the second temperature sensor 400 in a preset pouring area of the wall 10 , and pour the wall 10 to the top elevation of the wall 10 using ordinary concrete.

[0058] 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 changes inside the wall 10 and the temperature difference between the inside and the outside. Ordinary concrete is used to pour the wall 10.

[0059] S5: Based on the real-time monitoring results of the first temperature sensor 200 and the second temperature sensor 400, the power parameters of the electrode 300 are adjusted to synchronize the temperature change rate of the guide wall 100 with the temperature change rate of the wall 10. When the temperature of the wall 10 drops to the ambient temperature, the power supply 320 of the electrode 300 is disconnected.

[0060] Specifically, the temperature change curve of the concrete of the wall 10 is obtained based on the real-time monitoring data of the second temperature sensor 400, and whether the concrete has reached the final setting state is determined based on the final setting time data in the mix ratio report and the on-site concrete 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 to keep the center temperature difference between the guide wall 100 and the wall 10 within ±10°C. When the temperature of the concrete of the wall 10 reaches the peak, the cooling rate of the guide wall 100 is controlled to be synchronized with the cooling rate of the wall 10. When the temperatures of the wall 10 and the guide wall 100 both drop to the ambient temperature, the power is stopped and the wall 10 and the guide wall 100 are transferred to conventional maintenance.

[0061] Example 2: S1: Obtain conductive materials, set the conductive concrete mix ratio based on design requirements and construction specifications, and test the resistivity and specific heat capacity of the conductive concrete after a preset curing period.

[0062] The conductive concrete mix ratio is designed according to the design documents and construction requirements. The concrete strength grade is C40. Carbon fiber is used as the conductive material, and the carbon fiber volume content is designed to be 1.2%. The conductive concrete mix ratio is shown in Table 2 below.

[0063] Table 2 Conductive concrete mix ratio kg / m 3 cement fly ash Mineral powder gravel sand water reducer water carbon fiber 210 80 110 1085 723 4.8 152 36

[0064] S2: Obtain the resistance between the electrodes 300 based on the resistivity calculation, obtain the amount of heat required for heating the conductive concrete based on the specific heat capacity calculation, and obtain the electrode spacing based on the resistance and the amount of heat required for heating the conductive concrete.

[0065] The test results show that the resistivity of conductive concrete after 28 days is ρ = 25Ω∙m, the specific heat capacity is c = 980J / (kg·℃), and the bulk density is P = 2450kg / m 3 , a 36V power supply 320 is used on site for power supply. The concrete temperature rises by 20℃ after 18 hours of power supply. Substituting it into the formula, we can get l=26m.

[0066] It should be noted that the resistivity of conductive concrete can be obtained by the four-electrode 300 method and the two-electrode 300 method, and the specific heat capacity of conductive concrete can be obtained by hybrid calorimetry or differential scanning calorimetry. These are conventional technical means, and their working principles and structures will not be further described here.

[0067] S3: Pre-embed the first temperature sensor 200 in the preset casting area of the guide wall 100, pre-embed the electrode 300 in the preset casting area of the guide wall 100 according to the electrode spacing, use ordinary concrete to cast the bottom plate 20 to the bottom elevation of the guide wall 100, and use conductive concrete to cast the guide wall 100 to the bottom elevation of the wall body 10; Graphite rods are selected as electrodes 300, and the electrodes 300 are arranged at equal intervals on the guide wall 100 according to the calculated electrode 300 spacing, and the electrodes 300 are not in contact with the steel bars of the wall 10 and the bottom plate 20, and the bottom of the electrode 300 is buried in the guide wall 100 to a depth of the height of the guide wall 100. .

[0068] Before pouring concrete for the base plate 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. Ordinary concrete is used to cast the base plate 20. When the concrete reaches the bottom elevation of the guide wall 100, the conductive concrete is used to cast the guide wall 100. After the base plate 20 and the guide wall 100 are cured until the strength of the concrete reaches more than 70% of the design strength, the guide wall 100 is roughened.

[0069] S4: pre-embed the second temperature sensor 400 in the preset pouring area of the wall 10, and pour the wall 10 to the top elevation of the wall 10 using ordinary concrete; 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 changes inside the wall 10 and the temperature difference between the inside and the outside. Ordinary concrete is used to pour the wall 10.

[0070] S5: Based on the real-time monitoring results of the first temperature sensor 200 and the second temperature sensor 400, the power parameters of the electrode 300 are adjusted to synchronize the temperature change rate of the guide wall 100 with the temperature change rate of the wall 10. When the temperature of the wall 10 drops to the ambient temperature, the power supply 320 of the electrode 300 is disconnected.

[0071] Specifically, the temperature change curve of the concrete of the wall 10 is obtained based on the real-time monitoring data of the second temperature sensor 400, and whether the concrete has reached the final setting state is determined based on the final setting time data in the mix ratio report and the on-site concrete 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 to keep the center temperature difference between the guide wall 100 and the wall 10 within ±10°C. When the temperature of the concrete of the wall 10 reaches the peak, the cooling rate of the guide wall 100 is controlled to be synchronized with the cooling rate of the wall 10. When the temperatures of the wall 10 and the guide wall 100 both drop to the ambient temperature, the power is stopped and the wall 10 and the guide wall 100 are transferred to conventional maintenance.

[0072] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the scope of the present invention.

Claims

1. A wall crack control method based on temperature coordinated deformation, characterized in that: The invention is applied to the wall-bottom junction area of an ultra-long concrete structure, wherein a guide wall (100) is provided between the wall (10) and the bottom plate (20), the wall (10) is connected to the bottom plate (20) via the guide wall (100), a plurality of electrodes (300) and a plurality of first temperature sensors (200) are embedded in the guide wall (100), the plurality of electrodes (300) are evenly arranged in the guide wall (100), the plurality of electrodes (300) are connected to a power source (320) via a wire (310), the plurality of first temperature sensors (200) are evenly arranged in the guide wall (100), the first temperature sensors (200) are used to monitor temperature changes inside the guide wall (100), a plurality of second temperature sensors (400) are embedded in the wall (10), the plurality of second temperature sensors (400) are evenly arranged in the wall (10), and the second temperature sensors (400) are used to monitor temperature changes inside the wall (10); Wall crack control methods include: S1: Obtain conductive materials, set the conductive concrete mix ratio based on design requirements and construction specifications, and test the resistivity and specific heat capacity of the conductive concrete after a preset curing period. S2: Obtain the resistance between the electrodes (300) based on the resistivity calculation, obtain the heat required for heating the conductive concrete based on the specific heat capacity calculation, and obtain the electrode spacing based on the resistance and the heat required for heating the conductive concrete; S3: pre-embedding a first temperature sensor (200) in a preset casting area of the guide wall (100), pre-embedding an electrode (300) in a preset casting area of the guide wall (100) according to the electrode spacing, using ordinary concrete to cast the bottom plate (20) to the bottom elevation of the guide wall (100), and using conductive concrete to cast the guide wall (100) to the bottom elevation of the wall body (10); S4: pre-embedding a second temperature sensor (400) in a preset pouring area of the wall (10), and pouring the wall (10) to the top elevation of the wall (10) using ordinary concrete; S5: Based on the real-time monitoring results of the first temperature sensor (200) and the second temperature sensor (400), the power supply parameters of the electrode (300) are adjusted to synchronize the temperature change rate of the guide wall (100) with the temperature change rate of the wall (10), and the power supply (320) of the electrode (300) is disconnected when the temperature of the wall (10) drops to the ambient temperature.

2. The wall crack control method based on temperature coordinated deformation according to claim 1 is characterized in that: In S2, the electrode spacing is obtained based on the heat required to heat up the conductive concrete. The electrode spacing is calculated using the following formula: Where, is the electrode spacing, is the voltage across the conductor wall, is the time when the guide wall is energized, is the guide wall resistivity, is the bulk density of the guide wall, is the temperature rise of the guide wall, is the specific heat capacity of the guide wall.

3. The wall crack control method based on temperature coordinated deformation according to claim 1, characterized in that: In S3, the embedded electrode (300) is insulated from the structural steel bars of the bottom 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 bottom of the electrode (300) is buried in the guide wall (100) to a depth of at least 1 / 3 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: A first section (110), the first section (110) is provided between the wall (10) and the bottom plate (20), the first section (110) extends along the extension direction of the wall (10) to connect with the bottom plate (20), and a plurality of electrodes (300) are evenly distributed inside the first section (110); The second section (120) is provided on the first section (110), the second section (120) protrudes from the surface of the wall (10) and is connected to the bottom plate (20), and the cross-sectional area of at least a portion of the second section (120) gradually decreases in a direction away from the bottom plate (20), so as to reduce the shrinkage difference caused by the temperature difference between the guide wall (100) and the wall (10), thereby suppressing temperature cracks.

6. The wall crack control method based on temperature coordinated deformation according to claim 1, characterized in that: In S3, a plurality of first temperature sensors (200) are evenly arranged in the horizontal direction on a 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, a thread is provided on the surface of each electrode (300), and the thread is 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), wherein a plurality of first temperature sensing units (410) are uniformly arranged in a horizontal direction on a straight line where the geometric center of the wall (10) is located, and a plurality of second temperature sensing units (420) are uniformly arranged in a horizontal direction on the surface of the wall (10), and the first temperature sensing unit (410) cooperates with the second temperature sensing unit (420) to monitor the internal and external temperature difference 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 ordinary concrete is used to cast the wall (10) to the top elevation of the wall (10), the following steps are also included: Curing base plate (20) and guide wall (100); After the maintenance of the bottom plate (20) and the guide wall (100) is completed, 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, adjusting the energization parameters of the electrode (300) based on the real-time monitoring of the first temperature sensor (200) and the second temperature sensor (400) includes: Obtaining a temperature change curve of the wall (10) concrete based on real-time monitoring data from the second temperature sensor (400), and judging whether the concrete has reached a final setting state based on the concrete mix ratio and the on-site concrete state; The center temperature of the guide wall (100) and the center temperature of the wall (10) are monitored in real time by a first temperature sensor (200) and a second temperature sensor (400). When the concrete of the wall (10) reaches a final setting state, the output of the power supply (320) is dynamically adjusted so that the center temperature difference between the guide wall (100) and the wall (10) is maintained within ±10°C; When the concrete temperature of the wall (10) reaches a peak value, 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 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 transferred to conventional maintenance.

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