A mass concrete temperature drop rate early warning system and method
Patent Information
- Application Number
- CN202611017666.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-09
- Publication Date
- 2026-09-29
AI Technical Summary
[0007]本发明提供了一种大体积混凝土温降速率预警系统及方法，解决了现有上述背景技术所提出的问题，实现对混凝土结构不同部位温降温速率的实时自动监测，根据各部位温降速率差异设定分级预警阈值，实现精准预警，在温降速率超标时及时输出预警信号，指导施工人员及时采取保温措施，防止因温降过快导致混凝土裂缝的产生
[0028]1.通过在混凝土结构内部多个预定位置埋设振弦式内置温度传感器，并通过振弦式手持采集仪实时采集温度数据，实现了对大体积混凝土不同部位温度数据的实时自动采集，克服了人工测读效率低、易出错的缺陷；
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Abstract
Description
Technical Field
[0001] This invention relates to the field of large-volume concrete construction technology, and in particular to a system and method for early warning of temperature drop rate in large-volume concrete. Background Technology
[0002] In recent years, with the rapid development of underground engineering construction, tunnel engineering has been widely constructed and used throughout the country. However, tunnels generally suffer from damage such as water leakage, cracking and surrounding rock damage. Among these, tunnel cracking is one of the key issues affecting the safety of tunnel engineering.
[0003] There are many causes of tunnel cracks, but the thermal shrinkage during concrete pouring and curing has the most serious impact. Most urban underground tunnels are made of large-volume concrete, and the pouring and curing of their top slab, sidewalls and bottom slabs are often completed in a very short period of time. During the pouring and forming process, the huge volume of concrete releases a lot of heat and rises in temperature, accompanied by volume expansion. During the curing period, cooling and shrinkage make internal deformation inevitable, thus leading to the formation of micro-cracks and pores. When the tunnel is put into use, these micro-cracks and pores extend and expand under the action of external loads and internal stress diffusion, gradually developing into larger cracks and posing unknown hazards to traffic safety and human life and property.
[0004] Currently, the technology of compensating shrinkage concrete for large-volume concrete pouring has been widely studied and applied. By adding an expansion agent to the concrete, the heat of hydration is reduced and the expansion is limited, thereby controlling the temperature change range and alleviating internal deformation and stress concentration. However, the existing technology mainly focuses on the maximum temperature and the temperature difference between the inside and outside during the curing of large-volume concrete, and lacks a systematic solution for monitoring and early warning of the temperature drop rate.
[0005] Existing methods for monitoring the temperature of large-volume concrete typically rely on manual readings or automated temperature acquisition, with manual judgment based on the test results to determine whether temperature control measures should be taken. This approach has the following shortcomings: 1. It lacks real-time automatic monitoring and early warning functions for the rate of temperature drop, resulting in a lag in temperature control measures; 2. It cannot provide differentiated early warnings for temperature drop differences in different parts of the concrete structure; 3. The setting of early warning thresholds lacks scientific basis, making it difficult to effectively guide construction personnel to take timely insulation measures.
[0006] Therefore, there is an urgent need for a system and method that can monitor the rate of temperature drop in various parts of large-volume concrete in real time and provide graded early warnings. Summary of the Invention
[0007] This invention provides a system and method for early warning of temperature drop rate in large-volume concrete, which solves the problems mentioned in the background art. It realizes real-time automatic monitoring of the temperature drop rate in different parts of the concrete structure, sets graded early warning thresholds according to the differences in temperature drop rate in each part, achieves accurate early warning, and outputs early warning signals in a timely manner when the temperature drop rate exceeds the standard, guiding construction personnel to take timely insulation measures to prevent the formation of concrete cracks due to excessive temperature drop.
[0008] The solution to the above-mentioned technical problems of the present invention is as follows: a temperature drop rate early warning system and method for large-volume concrete, including a temperature acquisition module, a data processing module, an early warning judgment module, an alarm output module and a display module.
[0009] The temperature acquisition module includes a vibrating wire built-in temperature sensor embedded inside the concrete structure and a vibrating wire handheld acquisition device set outside the concrete structure. The vibrating wire built-in temperature sensor communicates with the vibrating wire handheld acquisition device via a signal line or wireless communication. The vibrating wire handheld acquisition device is used to receive temperature signals collected by each sensor. Through the combination of the vibrating wire sensor and the handheld acquisition device, stable acquisition of temperature signals from different parts inside a large volume of concrete can be achieved. The vibrating wire sensor has the advantages of strong anti-interference ability and stable signal transmission, and is suitable for long-term use in complex construction environments such as concrete pouring.
[0010] The data processing module is electrically connected to the vibrating wire handheld data acquisition device via wired or wireless means. The data processing module includes an A / D conversion unit, a microprocessor, and a memory connected in sequence. The A / D conversion unit is used to convert the analog temperature signal output by the vibrating wire handheld data acquisition device into a digital temperature signal. The microprocessor is used to calculate the real-time temperature drop rate of each measuring point based on the digital temperature signal. The memory is used to store the collected temperature data and preset temperature drop rate thresholds. Through the automated processing of the above data processing module, the collected analog signal can be converted into an analyzable digital signal in real time and the temperature drop rate calculation can be completed automatically, overcoming the shortcomings of low efficiency and error-prone calculation of manual measurement.
[0011] The early warning judgment module is electrically connected to the microprocessor of the data processing module. The early warning judgment module has a built-in comparator or executes a comparison algorithm through the microprocessor to compare the real-time temperature drop rate of each measuring point with a preset temperature drop rate threshold in the memory. When the real-time temperature drop rate of any measuring point exceeds the preset threshold, an early warning signal is generated. Through the automatic comparison and judgment of the above-mentioned early warning judgment module, real-time monitoring and automatic early warning of the temperature drop rate of large-volume concrete are realized, avoiding the lag of traditional manual judgment and enabling timely early warning in the early stage of temperature drop rate exceeding the standard.
[0012] The alarm output module is electrically connected to the early warning judgment module and is used to receive the early warning signal and output alarm information. Through the alarm output module, the early warning information can be promptly transmitted to the construction management personnel to ensure that the temperature control measures can be activated in a timely manner.
[0013] The display module is electrically connected to the microprocessor of the data processing module and is used to display the temperature data and temperature drop rate data of each measuring point in real time. Through the display module, construction personnel can intuitively grasp the real-time temperature status and temperature drop trend of each part of the concrete structure, which facilitates timely temperature control decisions.
[0014] Furthermore, the wireless communication methods include 4G communication, 5G communication, Wi-Fi communication, or Bluetooth communication. By using these multiple wireless communication methods, the most suitable communication scheme can be flexibly selected according to the actual conditions of the construction site, ensuring stable and reliable transmission of temperature data under different construction environments.
[0015] Furthermore, the multiple predetermined locations include the center position of the middle part of the concrete structure, the center position of the middle part in the thickness direction, the center position of the bottom, the inner surface position, and the outer surface position. By deploying sensors at the above multiple predetermined locations, temperature distribution data of different areas of the concrete structure can be comprehensively obtained. Since there are significant differences in the temperature change patterns inside and on the surface of large-volume concrete, the deployment at multiple points can effectively reflect the temperature field change characteristics of the overall structure.
[0016] Furthermore, the alarm output module includes an audible and visual alarm unit and a wireless communication unit; the audible and visual alarm unit is used to emit a warning light and a buzzer sound when receiving a warning signal; the wireless communication unit is wirelessly connected to an external mobile terminal and is used to send alarm information to the mobile terminal of the construction management personnel when receiving a warning signal. By combining audible and visual alarms with remote communication alarms, it is possible to ensure the immediate perception of personnel at the construction site and to enable timely notification to personnel at a remote location, effectively improving the transmission efficiency and coverage of warning information.
[0017] Furthermore, the display module includes an LCD screen, which is used to display the temperature change trend and temperature drop rate data of each measuring point in real time in the form of a temperature-time curve. By displaying the temperature change trend in the form of a curve, construction personnel can intuitively judge the temperature change trend of each measuring point, thereby more accurately assessing the temperature risk status of the concrete structure.
[0018] Furthermore, the preset temperature drop rate threshold includes a primary warning threshold and a secondary warning threshold, with the primary warning threshold being lower than the secondary warning threshold. When the real-time temperature drop rate exceeds the primary warning threshold but does not exceed the secondary warning threshold, the warning judgment module generates a primary warning signal. When the real-time temperature drop rate exceeds the secondary warning threshold, the warning judgment module generates a secondary warning signal. Through this graded warning mechanism, construction personnel can be reminded to prepare for insulation in advance when the temperature drop rate approaches a dangerous value, and an emergency alarm can be issued when the temperature drop rate exceeds a dangerous value, requiring immediate emergency measures to be taken. This achieves early intervention and graded response of temperature control measures.
[0019] The present invention also provides a method for early warning of temperature drop rate in large-volume concrete, employing the system described in any of the above claims, comprising the following steps:
[0020] S1: Vibrating wire built-in temperature sensors are embedded in multiple predetermined locations inside the concrete structure, and temperature data of each measuring point is collected in real time by a vibrating wire handheld data acquisition device.
[0021] S2: The data processing module calculates the real-time temperature drop rate of each measuring point according to the collected temperature data at predetermined time intervals. Through this step, the automatic real-time calculation of the temperature drop rate can be realized.
[0022] S3: The early warning judgment module compares the real-time temperature drop rate of each measuring point with the preset temperature drop rate threshold. Through this step, it can automatically determine whether the temperature drop rate of each measuring point exceeds the standard.
[0023] S4: When the real-time temperature drop rate at any measuring point exceeds the preset threshold, the alarm output module outputs a warning signal. Through this step, a warning signal can be output in a timely manner when the temperature drop rate exceeds the standard.
[0024] As a further improvement to the above method, the calculation method for the real-time temperature drop rate in step S2 is as follows: the microprocessor acquires the measured temperature value at the current moment and the measured temperature value at the previous acquisition moment, calculates the temperature difference between the two, and divides the temperature difference by the time interval to obtain the temperature drop rate; if the temperature difference is less than or equal to zero, the measuring point is in the heating or stable stage, and no warning judgment is made; if the temperature difference is greater than zero, the measuring point is in the cooling stage, and the process proceeds to step S3 to make a warning judgment. The above calculation method can accurately distinguish whether the concrete is in the heating, stable or cooling stage, and only makes a warning judgment in the cooling stage, avoiding false alarms in the heating stage and improving the accuracy of the warning.
[0025] As a further improvement to the above method, the preset temperature drop rate threshold is set separately for different parts of the concrete structure. The primary warning threshold for the measuring point in the internal central area is 3.0℃ / d and the secondary warning threshold is 3.5℃ / d, while the primary warning threshold for the measuring point in the surface area is 2.0℃ / d and the secondary warning threshold is 2.5℃ / d. Since the temperature rise and fall are greater closer to the internal center of the concrete structure, and the temperature drop rate in the internal central area is significantly higher than that in the surface area, setting different warning thresholds for different parts can achieve accurate monitoring and warning of the temperature in different areas, effectively improving the pertinence and reliability of the warning.
[0026] As a further improvement to the above method, the predetermined time interval in step S2 is as follows: during the first to seventh days after concrete pouring, temperature data is collected every 2 hours and the temperature drop rate is calculated; during the seventh to fifteenth days, temperature data is collected every 4 hours and the temperature drop rate is calculated. In the early stage of concrete pouring, the hydration reaction is intense and the temperature changes rapidly, so a higher acquisition frequency can capture temperature fluctuations in a timely manner; while in the later stage of curing, the temperature change tends to be gradual, and appropriately reducing the acquisition frequency can reduce system power consumption and data redundancy. The above-mentioned graded acquisition frequency setting not only ensures the monitoring accuracy during critical periods, but also achieves reasonable allocation of system resources.
[0027] The beneficial effects of this invention are as follows: This invention provides an early warning system and method for the temperature drop rate of large-volume concrete, which has the following advantages:
[0028] 1. By embedding vibrating wire built-in temperature sensors at multiple predetermined locations inside the concrete structure and collecting temperature data in real time using a vibrating wire handheld data acquisition device, real-time automatic acquisition of temperature data from different parts of large-volume concrete is achieved, overcoming the shortcomings of low efficiency and easy error in manual measurement.
[0029] 2. Through the coordinated operation of the A / D conversion unit, microprocessor and memory of the data processing module, the real-time temperature drop rate of each measuring point is automatically calculated, and the threshold comparison and early warning judgment are automatically performed by the early warning judgment module, realizing real-time automatic monitoring and early warning of the temperature drop rate, effectively avoiding the lag problem of traditional manual judgment;
[0030] 3. Based on a large amount of experimental data, scientific and reasonable graded early warning thresholds are set, and differentiated early warnings are given for different parts of the concrete structure according to the temperature drop differences. The first-level early warning threshold for the internal central area is 3.0℃ / d and the second-level early warning threshold is 3.5℃ / d, while the first-level early warning threshold for the surface area is 2.0℃ / d and the second-level early warning threshold is 2.5℃ / d. The early warning accuracy is high and can effectively guide construction personnel to take targeted temperature control measures in different parts.
[0031] 4. Through a graded early warning mechanism of Level 1 and Level 2, construction personnel are reminded to pay attention to temperature changes and prepare insulation measures when the rate of temperature drop exceeds the Level 1 threshold. When the rate of temperature drop exceeds the Level 2 threshold, an emergency alarm is issued requiring immediate emergency measures to be taken. This realizes the early intervention and graded response of temperature control measures, effectively preventing the generation of concrete cracks due to excessively rapid temperature drop.
[0032] 5. The alarm output module, composed of an audible and visual alarm unit and a wireless communication unit, along with the display module of an LCD screen, enables real-time on-site transmission and remote synchronous push of early warning information. At the same time, it visually displays the temperature change trend in the form of a temperature-time curve, facilitating construction management personnel to fully grasp the temperature risk status of the concrete structure and make timely and correct temperature control decisions.
[0033] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail in the following embodiments and their accompanying drawings. Attached Figure Description
[0034] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:
[0035] Figure 1 This is a system architecture diagram of a large-volume concrete temperature drop rate early warning system and method provided in an embodiment of the present invention;
[0036] Figure 2 This is a flowchart of a method for providing an early warning system and method for the temperature drop rate of large-volume concrete according to an embodiment of the present invention;
[0037] Figure 3 This is a temperature monitoring diagram of a large-volume concrete temperature drop rate early warning system and method provided in an embodiment of the present invention;
[0038] Figure 4 This is a temperature measurement data diagram of the concrete sidewall of a large-volume concrete temperature drop rate early warning system and method provided in an embodiment of the present invention. Detailed Implementation
[0039] The following is in conjunction with the appendix Figure 1-4The principles and features of the present invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. The invention is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.
[0040] It should be noted that when a component is said to be fixed to another component, it can be directly on the other component or it may have a component in between. When a component is said to be connected to another component, it can be directly connected to the other component or it may have a component in between. When a component is said to be set to another component, it can be directly set to the other component or it may have a component in between. The terms vertical, horizontal, left, right, and similar expressions used in this document are for illustrative purposes only.
[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The terminology used herein includes, and / or encompasses, any and all combinations of one or more of the associated listed items.
[0042] Example 1: Early Warning System Structure;
[0043] like Figure 1 As shown, the large-volume concrete temperature drop rate early warning system provided in this embodiment includes a temperature acquisition module, a data processing module, an early warning judgment module, an alarm output module, and a display module.
[0044] The temperature acquisition module includes multiple vibrating wire built-in temperature sensors embedded inside the concrete structure and a vibrating wire handheld acquisition device that communicates with each temperature sensor. The vibrating wire built-in temperature sensors are embedded inside the formwork at predetermined positions before the concrete is poured. The signal lines of each sensor are led out to the outside of the concrete structure and connected to the vibrating wire handheld acquisition device. The acquisition frequency range of the vibrating wire handheld acquisition device is 400 to 3500 Hz. The placement of each sensor is determined according to the type and size of the concrete structure.
[0045] The data processing module is connected to the vibrating wire handheld data acquisition device via wired or wireless means, and is used to receive temperature data transmitted by the data acquisition device. The data processing module includes an A / D conversion unit, a microprocessor, and a memory connected in sequence. The A / D conversion unit converts the analog temperature signal output by the vibrating wire handheld data acquisition device into a digital temperature signal. The microprocessor calculates the real-time temperature drop rate of each measuring point according to a predetermined algorithm based on the digital temperature signal. The memory is used to store the collected temperature data and the preset temperature drop rate threshold.
[0046] The early warning judgment module is electrically connected to the microprocessor of the data processing module. It has a built-in comparator or executes a comparison algorithm through the microprocessor to compare the real-time temperature drop rate of each measuring point with the preset temperature drop rate threshold in the memory, and generates an early warning signal when the real-time temperature drop rate of any measuring point exceeds the preset threshold.
[0047] The alarm output module is electrically connected to the early warning judgment module and is used to receive early warning signals and output alarm information in the form of sound, light, electricity or wireless communication.
[0048] The display module is electrically connected to the microprocessor of the data processing module and is used to display the temperature change curves and temperature drop rate data of each measuring point in real time in the form of charts.
[0049] Example 2: Temperature sensor deployment method;
[0050] Taking the sidewall of an underground highway tunnel as an example, the temperature sensor deployment method of the present invention will be described in detail.
[0051] like Figure 3 As shown, before the tunnel sidewall is poured, vibrating wire-type built-in temperature sensors are embedded in the following five predetermined locations inside the sidewall:
[0052] (1) First measuring point A: set at the center of the middle part of the side wall along its length;
[0053] (2) Second measuring point B: located at the center of the middle part of the side wall thickness direction;
[0054] (3) Third measuring point C: located at the bottom center position along the length of the side wall;
[0055] (4) Fourth measuring point D: located on the inner surface of the side wall;
[0056] (5) Fifth measuring point E: located on the outer surface of the side wall.
[0057] After all temperature sensors are installed, the sensor signal lines are led out to the outside of the concrete structure and connected to a vibrating wire handheld data acquisition device. The acquisition frequency range of the vibrating wire handheld data acquisition device is 400 to 3500 Hz.
[0058] Immediately after the concrete pouring is completed, the temperature acquisition module is activated to collect data. The acquisition frequency is set as follows: from the first to the seventh day after the concrete pouring, temperature data of each measuring point is collected every 2 hours; from the seventh to the fifteenth day, temperature data of each measuring point is collected every 4 hours.
[0059] Example 3: Method for calculating the rate of temperature drop;
[0060] This embodiment provides a detailed explanation of the specific method used by the data processing module to calculate the temperature drop rate.
[0061] Let Ti(tn) be the measured temperature of the i-th measuring point at time tn, and let Ti(t(n-1)) be the measured temperature at the previous time t(n-1). Let the time interval be... (In days), the real-time temperature drop rate Ri(tn) at the measuring point at time tn is calculated using the following formula:
[0062]
[0063] when When the temperature drops, it indicates that the measuring point is in the heating phase or the temperature stabilization phase, and the temperature drop rate is... No warning will be triggered at this time.
[0064] when When the temperature drops, it indicates that the measuring point is in the cooling phase, and the rate of temperature drop is... At this point, Ri(tn) is compared with a preset threshold.
[0065] Taking a data collection interval of 2 hours (i.e., 1 / 12 of a day) as an example, if the temperature at a certain measuring point at the current moment is Tn, and the temperature 2 hours ago was T(n-1), then the temperature drop rate is... (Unit: ℃ / d).
[0066] Example 4: Setting the early warning threshold;
[0067] This embodiment provides a detailed explanation of the method for setting the warning threshold based on experimental data.
[0068] The experiment used 42.5 grade ordinary Portland cement to prepare concrete with a water-cement ratio of 0.45 and added HME-V expansion agent (at a dosage of 8% of the binder). Temperature monitoring tests were conducted under standard curing conditions (temperature 20℃, humidity 95%).
[0069] During the curing period after the concrete sidewalls are poured, continuous temperature monitoring is conducted at each measuring point. Typical temperature data obtained are as follows: Figure 4 As shown.
[0070] from Figure 4 The data shows that:
[0071] (1) The closer the measuring point is to the center of the concrete structure, the greater the temperature rise and fall. The temperature drop of the measuring point at the center (length direction) is 17.1℃, and the temperature drop rate is 3.42℃ / d; the temperature drop of the measuring point at the bottom center is 18.2℃, and the temperature drop rate is 3.64℃ / d.
[0072] (2) The temperature drop rate of the surface measuring point is significantly lower than that of the internal center measuring point. The temperature drop rate of the inner surface measuring point is only 1.46℃ / d, while the temperature drop rate of the outer surface measuring point is 2.34℃ / d.
[0073] (3) The rate of temperature drop varies significantly in different parts, and warning thresholds need to be set for different parts.
[0074] Based on the above experimental data, the warning threshold set by this invention is as follows:
[0075] For the internal central area measuring points (including the central and bottom center locations), the first-level warning threshold is set at 3.0℃ / d, and the second-level warning threshold is set at 3.5℃ / d. When the temperature drop rate exceeds 3.0℃ / d but does not exceed 3.5℃ / d, the first-level warning is triggered, prompting construction personnel to pay attention to temperature changes and prepare to take insulation measures. When the temperature drop rate exceeds 3.5℃ / d, the second-level warning is triggered, prompting construction personnel to immediately take emergency measures such as covering with insulation materials.
[0076] For surface area measurement points (including inner and outer surface locations), the first-level warning threshold is set at 2.0℃ / d, and the second-level warning threshold is set at 2.5℃ / d.
[0077] Understandably, the above thresholds can be adjusted appropriately based on factors such as specific concrete mix proportions, structural dimensions, and ambient temperature. For example, when no expansion agent is added to the concrete, its temperature drop rate may be greater, and the warning threshold can be lowered accordingly; when the ambient temperature is low, the temperature drop rate may be faster, and the warning threshold also needs to be adjusted accordingly.
[0078] Example 5: Early Warning Method Flowchart;
[0079] like Figure 2 As shown, the early warning method provided in this embodiment includes the following steps:
[0080] Step S1: Temperature data acquisition. Before the concrete structure is poured, vibrating wire built-in temperature sensors are embedded in multiple predetermined locations. After the concrete is poured, temperature data of each measuring point is collected at predetermined time intervals using a vibrating wire handheld data acquisition device. The acquisition frequency is: once every 2 hours from day 1 to day 7, and once every 4 hours from day 7 to day 15.
[0081] Step S2: Temperature drop rate calculation. The data processing module receives the collected temperature data and calculates the real-time temperature drop rate at each measuring point using the following method:
[0082] For the i-th measuring point, obtain the measured temperature Ti(tn) at the current time tn and the measured temperature Ti(t(n-1)) at the previous sampling time t(n-1), and calculate the temperature difference. Dividing T by the time interval t (in days) yields the temperature drop rate Ri(tn).
[0083] like This indicates that the measuring point is in a warming or stable phase, and no early warning judgment is made.
[0084] like This indicates that the measuring point is in the cooling stage, and proceeds to step S3.
[0085] Step S3: Early warning judgment. The early warning judgment module compares the real-time temperature drop rate Ri(tn) of each measuring point with the preset early warning threshold of the location of that measuring point.
[0086] like If the Level 1 warning threshold is reached, no warning will be triggered, and monitoring will continue.
[0087] If the first-level warning threshold If the level 2 warning threshold is reached, a level 1 warning signal will be generated;
[0088] like If the level 2 warning threshold is reached, a level 2 warning signal will be generated.
[0089] Step S4: Alarm output. After receiving the warning signal, the alarm output module outputs the alarm information in the form of sound, light, electricity or wireless communication.
[0090] When a Level 1 warning signal is issued, the alarm output module emits a yellow warning light accompanied by an intermittent buzzer sound, and at the same time sends a prompt message to the mobile terminal of the construction management personnel, suggesting that the construction personnel check the insulation measures and prepare emergency supplies.
[0091] When a Level 2 warning signal is output, the alarm output module emits a red warning light and a continuous buzzing sound, and at the same time sends an emergency alarm message to the mobile terminal of the construction management personnel, requiring them to immediately take emergency measures such as covering with insulation materials and adjusting the cooling water flow to reduce the rate of temperature drop.
[0092] Example 6: System Working Process;
[0093] The following example, using the concrete pouring construction of the sidewall of an underground highway tunnel, illustrates the complete working process of the early warning system of this invention.
[0094] (1) Preparatory work: During the installation of tunnel sidewall formwork, in accordance with Figure 3Five pre-defined measuring points are embedded with vibrating wire-type built-in temperature sensors at the locations shown. The sensor signal lines are led out to the outside of the template and connected to a vibrating wire-type handheld data acquisition device. The data acquisition device is then connected to the data processing module. The warning thresholds for each measuring point are preset in the warning judgment module (first-level threshold 3.0℃ / d, second-level threshold 3.5℃ / d for the internal central area; first-level threshold 2.0℃ / d, second-level threshold 2.5℃ / d for the surface area).
[0095] (2) Concrete pouring: Prepare concrete according to the predetermined mix ratio (water-cement ratio 0.45, HME-V expansion agent dosage 8%) and pour the side walls.
[0096] (3) Temperature monitoring: After the concrete is poured, the temperature acquisition module is started immediately. Temperature data of each measuring point is collected every 2 hours from day 1 to day 7, and every 4 hours from day 7 to day 15. The data processing module calculates the temperature drop rate of each measuring point in real time.
[0097] (4) Early warning judgment and output: Assuming that on the 5th day after pouring, the measured temperature at the central (length direction) measuring point drops from 60.0℃ to 59.3℃ (2-hour interval), then the temperature drop rate is... When the value exceeds the secondary warning threshold of 3.5℃ / d, the warning judgment module immediately generates a secondary warning signal, the alarm output module emits a red warning light and a continuous buzzer sound, and sends an emergency alarm to the construction management personnel. After receiving the alarm, the construction personnel immediately cover the side wall surface with insulation material and check whether the cooling water system is operating normally, thereby effectively controlling the rate of temperature drop and preventing the generation of temperature cracks.
[0098] (5) Data display: Throughout the monitoring process, the display module displays the temperature change trend and temperature drop rate data of each measuring point in real time in the form of temperature-time curve, which makes it convenient for construction management personnel to intuitively grasp the temperature status of the concrete structure.
[0099] Example 7: System application with different amounts of expanding agent;
[0100] This embodiment illustrates the application of the early warning system of the present invention under different concrete mix proportions.
[0101] In practical engineering, large-volume concrete can be mixed with different proportions of HME-V expansive agent to compensate for shrinkage. According to experimental research, when the HME-V expansive agent dosage is 0%, 4%, 8%, 12%, and 16%, the slump of the concrete is controlled within the range of 180-20mm. As the dosage of expansive agent increases, the slump value steadily increases. Among them, a dosage of about 8% can give full play to the bonding effect of concrete binder, while ensuring construction workability.
[0102] Regarding the 28-day compressive strength, the compressive strength of concrete with each admixture exceeded 40 MPa, reaching the strength standard of C40 grade. Regarding the flexural strength, the 28-day flexural strength of concrete with each admixture was greater than 5 MPa. As the amount of expansive agent increased, the flexural strength decreased slightly, but the overall change was small.
[0103] Therefore, the early warning system of this invention is applicable to the construction of large-volume concrete with different amounts of expansive agent. Its early warning threshold can be appropriately adjusted according to the actual mix proportion. When the amount of expansive agent is low (e.g., 0% to 4%), the temperature drop rate of the concrete may be too high, so the early warning threshold can be appropriately lowered. When the amount of expansive agent is high (e.g., 12% to 16%), the concrete has better shrinkage compensation performance and the temperature drop rate is relatively slow, so the early warning threshold can be appropriately raised.
[0104] Example 8: Comparative application with fiber-reinforced concrete;
[0105] This embodiment illustrates the application of the early warning system of the present invention in concrete incorporating polypropylene fibers.
[0106] According to experimental research, the slump value of concrete with 0.4% polypropylene fiber is similar to that of impermeable concrete with 4% expansion agent. In terms of 7-day compressive strength, the compressive strength of concrete with 0.4% fiber is higher than that of pure concrete with 0% expansion agent. However, in terms of 28-day strength, the compressive strength of concrete with fiber is lower than that of all expansion agent specimens. This indicates that the fiber plays a role in reinforcing and setting the concrete during curing. The higher compressive strength in the early stage is due to the friction and adhesion of the fiber between particles. In terms of flexural strength, the flexural strength of concrete with polypropylene fiber is similar to that of concrete with 8% expansion agent.
[0107] For large-volume concrete incorporating polypropylene fibers, the temperature drop rate characteristics are different from those of concrete incorporating expansive agents. The early warning system of this invention is also applicable. The early warning threshold can be referenced from the set value of concrete incorporating expansive agents and finely adjusted according to actual monitoring data.
[0108] Example 9: Application of the system in the tunnel roof and floor slabs;
[0109] This embodiment illustrates the application of the early warning system of the present invention in the pouring of tunnel roof and floor slabs.
[0110] Most urban underground tunnels are made of large-volume concrete. The pouring and curing of the top slab, side walls and bottom slab are often completed in a very short period of time. The huge volume of concrete releases a lot of heat and rises in temperature during the pouring process, and expands in volume. During the curing period, it cools down and shrinks, making internal deformation inevitable.
[0111] For the tunnel roof, the sensor placement locations may include: the center position in the thickness direction, the center position in the length direction, the upper surface position, and the lower surface position. For the tunnel floor, the sensor placement locations may include: the center position in the thickness direction, the center position in the length direction, the upper surface position, and the lower surface position.
[0112] The temperature monitoring and early warning methods for each part are the same as those for the sidewalls. By deploying sensors at multiple predetermined locations, the temperature distribution data of the entire tunnel structure can be obtained comprehensively, effectively guiding temperature control measures for each part.
[0113] Example 10: Adjustability of system parameters;
[0114] Those skilled in the art should understand that the specific parameters in the above embodiments (such as warning threshold, acquisition frequency, sensor deployment location, etc.) are merely illustrative examples and are not intended to limit the present invention.
[0115] In practical applications, the setting of the warning threshold can be adjusted based on the following factors:
[0116] (1) Concrete mix proportion: Different cement types, water-cement ratios, and expansion agent dosages will affect the hydration heat release rate and temperature drop characteristics of concrete;
[0117] (2) Structural dimensions: The larger the size of a large-volume concrete structure, the higher the internal temperature and the slower the rate of temperature drop;
[0118] (3) Environmental conditions: Ambient temperature, humidity, wind speed and other external conditions will affect the heat dissipation rate of concrete surface.
[0119] (4) Maintenance conditions: The thickness of the insulation covering material and the arrangement of the cooling water pipes will affect the rate of temperature drop.
[0120] The sampling frequency can also be adjusted according to the actual situation: during the peak period of concrete hydration heat release (generally 2 to 5 days after pouring), the sampling frequency can be appropriately increased; after the temperature tends to stabilize, the sampling frequency can be appropriately reduced to save system resources.
[0121] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Content not described in detail in this specification is prior art known to those skilled in the art.
[0122] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.
Claims
1. A temperature drop rate early warning system for large-volume concrete, comprising a temperature acquisition module, a data processing module, an early warning judgment module, an alarm output module, and a display module, characterized in that, The temperature acquisition module includes a vibrating wire built-in temperature sensor embedded inside the concrete structure and a vibrating wire handheld acquisition device set outside the concrete structure. The vibrating wire built-in temperature sensor is connected to the vibrating wire handheld acquisition device via a signal line or wireless communication. The vibrating wire handheld acquisition device is used to receive temperature signals collected by each sensor. The data processing module is electrically connected to the vibrating wire handheld data acquisition device via wired or wireless means. The data processing module includes an A / D conversion unit, a microprocessor, and a memory that are electrically connected in sequence. The A / D conversion unit is used to convert the analog temperature signal output by the vibrating wire handheld data acquisition device into a digital temperature signal; the microprocessor is used to calculate the real-time temperature drop rate of each measuring point based on the digital temperature signal; the memory is used to store the acquired temperature data and the preset temperature drop rate threshold. The early warning judgment module is electrically connected to the microprocessor of the data processing module. The early warning judgment module has a built-in comparator or executes a comparison algorithm through the microprocessor to compare the real-time temperature drop rate of each measuring point with the preset temperature drop rate threshold in the memory. When the real-time temperature drop rate of any measuring point exceeds the preset threshold, an early warning signal is generated. The alarm output module is electrically connected to the early warning judgment module and is used to receive the early warning signal and output alarm information; The display module is electrically connected to the microprocessor of the data processing module and is used to display the temperature data and temperature drop rate data of each measuring point in real time.
2. The early warning system for the temperature drop rate of large-volume concrete according to claim 1, characterized in that, The wireless communication methods include 4G communication, 5G communication, Wi-Fi communication, or Bluetooth communication.
3. The early warning system for the temperature drop rate of large-volume concrete according to claim 1, characterized in that, The predetermined locations include the central position of the concrete structure, the central position in the thickness direction, the central position at the bottom, the inner surface position, and the outer surface position.
4. The early warning system for the temperature drop rate of large-volume concrete according to claim 1, characterized in that, The alarm output module includes an audible and visual alarm unit and a wireless communication unit; the audible and visual alarm unit is used to emit a warning light and a buzzer sound when receiving a warning signal; the wireless communication unit is wirelessly connected to an external mobile terminal and is used to send alarm information to the mobile terminal of the construction management personnel when receiving a warning signal.
5. The early warning system for the temperature drop rate of large-volume concrete according to claim 1, characterized in that, The display module includes an LCD screen, which is used to display the temperature change trend and temperature drop rate data of each measuring point in real time in the form of a temperature-time curve.
6. The early warning system for the temperature drop rate of large-volume concrete according to claim 1, characterized in that, The preset temperature drop rate threshold includes a primary warning threshold and a secondary warning threshold, wherein the primary warning threshold is lower than the secondary warning threshold; when the real-time temperature drop rate exceeds the primary warning threshold but does not exceed the secondary warning threshold, the warning judgment module generates a primary warning signal; When the real-time temperature drop rate exceeds the level 2 warning threshold, the warning judgment module generates a level 2 warning signal.
7. A method for early warning of temperature drop rate in large-volume concrete, characterized in that, The system described in any one of claims 1 to 6 includes the following steps: S1: Install vibrating wire built-in temperature sensors at multiple predetermined locations inside the concrete structure, and collect temperature data of each measuring point in real time using a vibrating wire handheld data acquisition device. S2: The data processing module calculates the real-time temperature drop rate of each measuring point according to the collected temperature data and at a predetermined time interval. S3: The early warning judgment module compares the real-time temperature drop rate of each measuring point with the preset temperature drop rate threshold. S4: When the real-time temperature drop rate at any measuring point exceeds the preset threshold, the alarm output module outputs a warning signal.
8. The method for early warning of temperature drop rate in large-volume concrete according to claim 7, characterized in that, The calculation method for the real-time temperature drop rate in step S2 is as follows: the microprocessor acquires the measured temperature value at the current moment and the measured temperature value at the previous acquisition moment, calculates the temperature difference between the two, and divides the temperature difference by the time interval to obtain the temperature drop rate; if the temperature difference is less than or equal to zero, the measuring point is in the heating or stable stage, and no warning judgment is made; if the temperature difference is greater than zero, the measuring point is in the cooling stage, and the process proceeds to step S3 to make a warning judgment.
9. The method for early warning of temperature drop rate in large-volume concrete according to claim 7, characterized in that, The preset temperature drop rate thresholds are set according to different parts of the concrete structure. The first-level warning threshold for the measuring point in the internal central area is 3.0℃ / d, and the second-level warning threshold is 3.5℃ / d. The first-level warning threshold for the measuring point in the surface area is 2.0℃ / d, and the second-level warning threshold is 2.5℃ / d.
10. The method for early warning of temperature drop rate in large-volume concrete according to claim 7, characterized in that, The predetermined time interval mentioned in step S2 is as follows: during the first to seventh days after concrete pouring, temperature data is collected every 2 hours and the temperature drop rate is calculated; during the seventh to fifteenth days, temperature data is collected every 4 hours and the temperature drop rate is calculated.