Rockfill concrete compactness detection device and method thereof

Abstract

This application relates to a device for testing the density of riprap concrete, comprising: induction electrodes disposed between the riprap bodies, each induction electrode including two sensing ends for acquiring the resistance value between the two sensing ends; a detection module electrically connected to the induction electrodes, the detection module being used to convert the resistance value into a resistance level and obtain a curve of the resistance level change; and a data processing module electrically connected to the detection module, the data processing module acquiring a first signal L from the resistance level change curve. A Second signal L B and the third signal L C And based on the size relationship of the three and the third signal L C The values ​​of L and L together determine the density of the concrete, where the first signal L is the density of the concrete. A The resistance level is the value when the sensing electrode is not in contact with the concrete, and the second signal L is... B The resistance level is at the moment the sensing electrode just contacts the concrete, and the third signal L C This refers to the resistance level after the inductive electrode has been in stable contact with the concrete. This application can determine the density level of the concrete, making the test results more precise.

Description

Technical Field

[0001] This application relates to the field of construction technology, specifically to the fields of water conservancy engineering, transportation, marine engineering, municipal engineering and building construction, and particularly to a device for testing the density of riprap concrete and a method for testing it. Background Technology

[0002] Rockfill concrete is a novel large-volume concrete technology that utilizes high-performance self-compacting concrete (HSCC) to fill the voids in the rockfill mass, forming a complete, dense concrete that meets design requirements. Rockfill concrete includes ordinary rockfill concrete, which refers to a technique where rocks are first piled up and then high-performance self-compacting concrete is poured. This type is primarily suitable for gravity dams, arch dams, concrete cofferdams, and embankments.

[0003] In the construction of rockfill concrete, the density of the filling plays a decisive role in the overall strength and durability of the dam. Currently, for completed rockfill concrete dams, methods such as core drilling, in-hole television, ultrasonic testing, and infrared imaging are commonly used to assess the density of the concrete filling inside the dam. However, these methods cannot assess the density of the concrete filling inside the dam in real time during construction, making it difficult to detect problems promptly. Furthermore, these testing methods can only determine whether the rockfill concrete is dense, but cannot accurately evaluate the degree of concrete density. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this application proposes a device for testing the density of riprap concrete, comprising: one or more inductive electrodes disposed between the riprap bodies, each inductive electrode including two sensing ends for collecting the resistance value between the two sensing ends; a detection module electrically connected to the inductive electrodes to form an electrode group, the detection module being used to convert the resistance value into a resistance level and obtain a curve showing the change of the resistance level during concrete pouring; and a data processing module electrically connected to the detection module, the data processing module acquiring a first signal L from the curve showing the change of the resistance level. A Second signal L B and the third signal L C And according to the first signal L A Second signal L B and the third signal L C The magnitude relationship and the third signal L C The values ​​of L and L together determine the density of the concrete, wherein the first signal L A The resistance level is the value when the sensing electrode is not in contact with the concrete, and the second signal L is... BThe resistance level is at the moment the sensing electrode just contacts the concrete, and the third signal L is... C The resistance value is the level after the electrode is in stable contact with the concrete.

[0005] As described above, in the riprap concrete density testing device, the sensing electrode includes a first resistor R1 and an equivalent resistance disposed between the two sensing terminals, namely: a third resistor R HSCC The detection module includes: a second resistor R2, one end of which is electrically connected to a power supply, and the other end of which is electrically connected to one end of a first resistor R1. The other end of the first resistor R1 is grounded. The first resistor R1 and the third resistor R HSCC Parallel connection; analog-to-digital converter for converting the first resistor R1 and the third resistor R HSCC The voltage value at both ends is converted into a resistance value.

[0006] As described above, in the riprap concrete density testing device, the resistance level of the sensing electrode when it is not in contact with the concrete is:

[0007] ADC AIN1 = [R1÷(R1+R2)]×L

[0008] Among them, ADC AIN1 R1 represents the resistance levels between the sensing terminals, R2 represents the first resistance, R2 represents the second resistance, and L represents the maximum value of the resistance levels.

[0009] As described above, in the riprap concrete density testing device, the resistance level of the sensing electrode when it first contacts the concrete or after it has been in stable contact with the concrete is:

[0010]

[0011] Among them, ADC AIN1 The resistance values ​​between the sensing terminals are in the range, where R1 is the first resistor, R2 is the second resistor, and R... HSCC L represents the equivalent resistance between the two sensing terminals, where L is the maximum value of the resistance range.

[0012] In the riprap concrete density testing device described above, the resistance of the first resistor R1 is 10-50 times the resistance of the second resistor R2.

[0013] The riprap concrete compaction testing device described above further includes: a data acquisition module electrically connected to multiple electrode groups connected in series, for collecting the resistance value of each of the sensing electrodes in the electrode groups and sending the collected resistance value to the data processing module.

[0014] The riprap concrete density testing device described above further includes: one or more temperature sensors disposed between the riprap bodies for detecting temperature values ​​during concrete pouring and sending the temperature values ​​to a data processing module; the data processing module, based on the first signal L... A Second signal L B and the third signal L C The magnitude relationship, the third signal L C The density of concrete is determined by the numerical value of the concrete and the temperature value.

[0015] As described above, the width of the two sensing ends of the riprap concrete compaction testing device is 2mm-3mm, and the length is 20mm-30mm.

[0016] According to another aspect of this application, a method for detecting the density of riprap concrete is proposed. This method is based on the aforementioned riprap concrete density detection device and includes: filling a riprap area with riprap material and placing multiple inductive electrodes at different positions within the riprap material; pouring concrete into the riprap area and collecting the resistance value between two inductive terminals using the inductive electrodes; converting the resistance value into a resistance level using a detection module and obtaining a resistance level change curve during concrete pouring; and acquiring a first signal L from the resistance level change curve. A Second signal L B and the third signal L C The first signal L A The resistance level is the value when the sensing electrode is not in contact with the concrete, and the second signal L is... B The resistance level is at the moment the sensing electrode just contacts the concrete, and the third signal L is... C The resistance level after the sensing electrode has made stable contact with the concrete; based on the first signal L A Second signal L B and the third signal L C The magnitude relationship and the third signal L C The values ​​of these factors together determine the density of the concrete.

[0017] As described above, when the first signal L A >Third signal L C > Second signal L B And the third signal L C When the density is ∈ [0.65L, 0.80L], the concrete density at the location of the sensing electrode is completely dense.

[0018] As described above, when the first signal L A >Third signal L C > Second signal L BAnd the third signal L C When ∈(0.80L, 0.90L], the concrete density at the location of the sensing electrode is partially dense.

[0019] As described above, the first signal L A ∈(0.90L, 0.98L).

[0020] As described above, when the first signal L A When the value is L, it is determined that the riprap concrete compaction testing device has experienced an open circuit; when the first signal L... A When the value approaches 0, it is determined that the riprap concrete density testing device has short-circuited.

[0021] As described above, the type of concrete includes self-compacting concrete and normal concrete.

[0022] This application utilizes a riprap concrete density testing device to obtain the resistance level change curve during concrete pouring, and based on the first signal L in the resistance level change curve... A Second signal L B and the third signal L C The magnitude relationship determines whether the corresponding sensing electrode is abnormal. If an abnormality is found, the sensing electrode is shielded and no longer participates in the detection. A self-test function is performed before detection to rule out abnormal sensing electrodes. When the sensing electrode is working normally, the third signal L... C The numerical value determines the density of concrete. The third signal L is used. C The numerical value can accurately determine the density level of concrete, making the test results more refined and providing great guidance for the next stage of construction. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the internal module structure of a riprap concrete compaction testing device according to an embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the sensing electrode structure according to an embodiment of this application;

[0025] Figure 3A This is a circuit diagram of a detection module according to an embodiment of this application;

[0026] Figure 3B This is a schematic diagram of the detection module structure according to an embodiment of this application; Figure 4 This is a graph showing the change in resistance levels during concrete pouring according to an embodiment of this application;

[0027] Figure 5This is a flowchart of a method for testing the density of riprap concrete according to an embodiment of this application;

[0028] Figure 6 This is a schematic diagram of on-site concrete compaction testing according to an embodiment of this application; and

[0029] Figure 7 This is a schematic diagram of the resistance level changes of multiple sensing electrodes in the field according to an embodiment of this application. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] In the following detailed description, reference can be made to the accompanying drawings, which form part of this application and illustrate specific embodiments of the present application. In the drawings, similar reference numerals describe substantially similar components in different figures. Specific embodiments of the present application are described in sufficient detail below to enable those skilled in the art to implement the technical solutions of the present application. It should be understood that other embodiments may also be utilized, or structural, logical, or electrical changes may be made to the embodiments of the present application.

[0032] To address the aforementioned problems, this application discloses a riprap concrete density testing device. This device uses inductive electrodes placed between the riprap sections to collect the resistance value between the two inductive terminals. The resistance value is then processed through a series of calculations to determine the density of the riprap concrete near the inductive electrodes. When the density does not meet requirements, an alarm is immediately issued, allowing for remedial measures to be taken at that location. This has significant application value in improving the construction quality of riprap concrete. Furthermore, before testing, the riprap concrete density testing device performs a self-check function. If a particular inductive electrode malfunctions, it is actively shielded to avoid affecting the testing accuracy. Figure 1 This is a schematic diagram of the internal module structure of a riprap concrete compaction testing device according to an embodiment of this application. Figure 1As shown, the riprap concrete density testing device 100 includes one or more induction electrodes 110, a testing module 120, a data acquisition module 130, a data processing module 140, and a data center 150. Each testing module 120 can be electrically connected to multiple induction electrodes 110 simultaneously, forming an electrode group. The induction electrodes 110 are disposed between the riprap bodies and include two sensing ends. The testing module 120 converts the resistance value between the two sensing ends into a resistance level and obtains a curve showing the change in resistance level during concrete pouring. One testing module 120 can be electrically connected to up to four induction electrodes 110 simultaneously, allowing one testing module 120 to detect more locations and improving the utilization rate of the testing module 120. After the riprap is completed, induction electrodes are placed and properly fixed between the riprap bodies prone to density problems.

[0033] According to one embodiment of this application, multiple detection modules 120 are connected in series, and the series-connected detection modules 120 are electrically connected to a data acquisition module 130. The data acquisition module is used to collect the resistance values ​​of each sensing electrode in the electrode group and send the collected resistance values ​​to the data processing module. The number of detection modules 120 connected in series can be 1-80. Compared with simultaneously connecting multiple detection modules 120 to the data acquisition module, connecting multiple detection modules 120 in series to the data acquisition module 130 is simpler to install and saves on wiring resources when deploying multi-point monitoring. Furthermore, the data acquisition module 130 has limited interfaces; connecting one detection module 120 to each interface would limit the number of sensing electrodes 110 that can be arranged, making it impossible to simultaneously monitor the same dam body from all angles. Therefore, using a series connection method increases the number of detection modules 120 that can be connected simultaneously, increases the number of detection positions, and improves the detection accuracy. The detection module 120 is equipped with an RS485 interface at both ends. The use of RS485 interfaces for series connection has the advantages of maximizing data transmission quality, easy maintenance and low cost.

[0034] The data acquisition module 130 includes a wireless module 131 for receiving and transmitting data; the data processing module 140 includes a wireless module 141 for receiving and transmitting data, and the data processing module 140 is used to acquire a first signal L from the resistance value level change curve. A Second signal L B and the third signal L C And according to the first signal L A Second signal L B and the third signal L C The magnitude relationship and the third signal L C The values ​​of L and L together determine the density of the concrete, wherein the first signal L AThe resistance level is the value when the sensing electrode is not in contact with the concrete, and the second signal L B The resistance level is at the moment the sensing electrode just contacts the concrete, and the third signal L C This represents the resistance level after the sensing electrode has made stable contact with the concrete. Wireless modules 131 and 141 can be LoRa wireless modules or other types of wireless modules; no restrictions are placed here.

[0035] The data processing module 140 can be installed on the construction site or in a cloud server; there are no restrictions. Users can choose freely according to their construction conditions. The data processing module 140 can upload the processed data to the data center 150 via wired or wireless means; wireless transmission can use the Internet. When the data processing module 140 determines that the compaction of the riprap concrete at a certain location is unqualified, it can send an alarm message to the mobile device of the person in charge at the site via SMS, WeChat, or telephone. The person in charge at the site can then promptly take remedial measures such as auxiliary vibration at the corresponding location based on the alarm message.

[0036] Figure 2 This is a schematic diagram of the induction electrode structure according to an embodiment of this application. Figure 2 As shown, the sensing electrode 110 is inserted into self-compacting concrete (HSCC) to detect the resistance value in the self-compacting concrete. The sensing electrode 110 includes a first resistor R1 disposed between the X1 and X2 input terminals and an equivalent third resistor R disposed between the first sensing terminal B1 and the second sensing terminal B2. HSCC The sensing electrode 110 is placed between the riprap. During concrete pouring, the space between the first sensing terminal B1 and the second sensing terminal B2 on the sensing electrode 110 will be filled with concrete. Concrete is a poor conductor; when the first sensing terminal B1 and the second sensing terminal B2 are filled with concrete, the resistance of the concrete can be considered as a third resistance R. HSCC The first sensing terminal B1 and the second sensing terminal B2 are good conductors, and their materials can be stainless steel, copper, etc. The shapes of the first sensing terminal B1 and the second sensing terminal B2 include plate-like structures and columnar structures. Their equivalent length is 10mm-40mm, and their equivalent width is 1mm-5mm; preferably, the equivalent length is 20mm-30mm, and the width is 2mm-3mm. The distance between the first sensing terminal B1 and the second sensing terminal B2 is 5mm-50mm; preferably, the distance between them is 10mm-20mm. When the equivalent length of the first sensing terminal B1 and the second sensing terminal B2 is 20mm-30mm, the equivalent width is 2mm-3mm, and the distance between them is 10mm-20mm, the detection sensitivity of the first sensing terminal B1 and the second sensing terminal B2 is high, and the detection accuracy is also high.

[0037] Figure 3A This is a circuit diagram of a detection module according to an embodiment of this application. Figure 3A As shown, the detection module circuit includes a second resistor R2. One end of the second resistor R2 is electrically connected to the power supply, and the other end is electrically connected to one end of the first capacitor C1. The other end of the first capacitor C1 is grounded. When the sensing electrode 110 is electrically connected to the detection module 120, the sensing electrode 110 and the first capacitor C1 are connected in parallel, that is, the other end of the second resistor R2 is electrically connected to one end of the first resistor R1, and the other end of the first resistor R1 is grounded. The first resistor R1 and the third resistor R... HSCC Parallel connection. Using the detection module circuit, the third resistance R can be obtained. HSCC The change in resistance is used to detect the density of concrete.

[0038] Figure 3B This is a schematic diagram of the detection module structure according to an embodiment of this application. Figure 3B As shown, the detection module 120 includes a processor 121 and an analog-to-digital converter 122. The processor 121 is electrically connected to the analog-to-digital converter 122 and is used to process data sent from the analog-to-digital converter 122. The processor can be an MCU. The analog-to-digital converter 122 is electrically connected to one or more sensing electrodes 110 for data acquisition. Figure 3A The electrical signal at AIN1 is used to connect the first resistor R1 and the third resistor R HSCC The voltage value at both ends is converted into a resistance value. When the analog-to-digital converter 122 acquires the voltage signal, it first divides the acquisition range into L parts, and assigns the acquired voltage signal to numbers from 0 to L. The larger the value of L, that is, the more segments the electrical signal is divided into, the higher the accuracy of the final calculated measurement value. The analog-to-digital converter 122 in this application uses a 10-16 bit resolution. For example, when the analog-to-digital converter 122 is 16 bits, it is 2... 16 =65536.

[0039] Figure 4 This is a graph showing the change in resistance levels during concrete pouring according to an embodiment of this application. Figure 4 As shown, during the pouring of riprap concrete, the entire testing process can be divided into three stages, each corresponding to the resistance value at AIN1 and the ADC level. AIN1 They are all different, combined Figures 2 to 4 As shown, the specific content of the three stages is as follows:

[0040] Phase 1

[0041] When the sensing electrode 110 is electrically connected to the detection module 120, and the first sensing terminal B1 and the second sensing terminal B2 of the sensing electrode 110 are not in contact with the riprap concrete, the space between the first sensing terminal B1 and the second sensing terminal B2 is air, and the corresponding resistance value tends to infinity. Figure 4 The straight line before point A. At this point, the resistance value at AIN1 is equal to that of the ADC. AIN1 The first signal L A First signal L A The calculation formula is as follows:

[0042] ADC AIN1 = [R1÷(R1+R2)]×L;(1)

[0043] Among them, ADC AIN1 The resistance level ADC at AIN1 AIN1 R1 is the first resistor, R2 is the second resistor, and L is the maximum value of the resistance range.

[0044] According to one embodiment of this application, the resistance value of the first resistor R1 is 10-50 times that of the second resistor R2. Referring to formula (1), when the resistance value of the first resistor R1 is 10-50 times that of the second resistor R2, the first signal L before point A... A ∈[0.91L, 0.98L]. Since the resistor used has an accuracy of approximately 1%, the first signal L... A When set within the above range, a difference of 0.1L can be used as the detection range of the sensing electrode, so that the remaining 0.9L can be used as the effective reading range, thereby improving the detection accuracy of the riprap concrete compaction testing device.

[0045] Phase Two

[0046] When the sensing electrode 110 is electrically connected to the detection module 120, and the first sensing end B1 and the second sensing end B2 of the sensing electrode 110 just come into contact with the riprap concrete, the corresponding... Figure 4 The resistance level at point B. The resistance level at AIN1 at this time is the same as that of the ADC. AIN1 For the second signal L B The second signal L B The calculation formula is as follows:

[0047]

[0048] Among them, ADC AIN1 The resistance level ADC at AIN1 AIN1 R1 is the first resistor, R2 is the second resistor, and R HSCC L is the equivalent resistance between the first sensing terminal B1 and the second sensing terminal B2, and L is the maximum value of the resistance level.

[0049] When the sensing electrode 110 is electrically connected to the detection module 120, and the first sensing end B1 and the second sensing end B2 of the sensing electrode 110 just come into contact with the riprap concrete, the equivalent resistance R between the first sensing end B1 and the second sensing end B2 is...HSCC When a sudden change occurs (from infinity to a sudden decrease), the resistance value also drops to a lower level, resulting in a "jump". In this application, the "jump" can be considered as the signal that the sensing electrode begins to contact the riprap concrete, and the second signal L at this time is recorded. B The magnitude of the resistance value.

[0050] Phase Three

[0051] When the sensing electrode 110 is electrically connected to the detection module 120, and the first sensing end B1 and the second sensing end B2 of the sensing electrode 110 are in stable contact with the riprap concrete, the corresponding... Figure 4 The straight line after point C. At this point, the resistance value at AIN1 corresponds to the ADC value. AIN1 For the third signal L C The third signal L C Formula (2) is still used for calculation. However, the equivalent resistance R between the first sensing terminal B1 and the second sensing terminal B2 is different. HSCC The resistance will change upon initial contact with the riprap concrete and after the concrete has stabilized. From formula (2), the equivalent resistance R between the first sensing terminal B1 and the second sensing terminal B2 is... HSCC The resistance value changes, and the resistance value at AIN1 corresponds to the ADC. AIN1 This will also change. Therefore, according to the first signal L A Second signal L B and the third signal L C The magnitude relationship and the third signal L C The values ​​can be used to jointly determine the density of concrete, and the results are highly reliable.

[0052] When the sensing electrode 110 is electrically connected to the detection module 120, and the first sensing end B1 and the second sensing end B2 of the sensing electrode 110 come into contact with the riprap concrete, anions in the riprap concrete between the first sensing end B1 and the second sensing end B2 will move towards the anode of the electrode, while cations will move towards the cathode. Since free ions are uniformly distributed in the riprap concrete when the first sensing end B1 and the second sensing end B2 first come into contact with it, a large number of free ions are adsorbed nearby after the first sensing end B1 and the second sensing end B2 come into contact with the riprap concrete, reducing the surrounding free ion density. This leads to a decrease in the conductivity of the concrete at both ends of the first sensing end B1 and the second sensing end B2, thereby reducing the equivalent resistance R between the first sensing end B1 and the second sensing end B2. HSCC Increase, therefore the resistance value at AIN1 is equal to that of the ADC. AIN1 It will increase and then gradually stabilize. As time goes by, the concrete slowly solidifies, and the moisture content decreases. The equivalent resistance of the first sensing terminal B1 and the second sensing terminal B2 gradually increases, and the resistance value at AIN1 is similar to that of the ADC.AIN1 It will also gradually increase in size.

[0053] According to one embodiment of this application, the riprap concrete density testing device further includes: one or more temperature sensors disposed between the riprap bodies near the sensing electrodes, for detecting temperature values ​​during the concrete pouring process, and sending the temperature values ​​to a data processing module; the data processing module, based on a first signal L... A Second signal L B and the third signal L C Size relationship, third signal L C The density of concrete is determined by the temperature value and the temperature value. Specifically, before the temperature sensor is covered by concrete, the value measured by the temperature sensor is the ambient temperature or the temperature of the riprap. After the temperature sensor is buried in concrete, it changes rapidly and then changes with the temperature of the concrete. Therefore, by cross-referencing the time point of the temperature sensor's "abrupt change" with the time point of the sensing electrode's "jump," the time it takes for the concrete to reach that location can be determined, thus aiding in the judgment and enhancing its accuracy.

[0054] From formula (2), it can be seen that the third signal L C The smaller the value, the denser the concrete filling between the sensing electrodes; conversely, the larger the value, the less dense the concrete. However, the third signal L... C The specific numerical values ​​corresponding to the density relationship require extensive experimentation to establish. Furthermore, the change curves of resistance levels can indicate different stages of concrete pouring, which, combined with the third signal L... C The numerical range allows for quick determination of concrete density. For specific methods on determining density, please refer to the following:

[0055] Figure 5 This is a flowchart of a method for testing the density of riprap concrete according to an embodiment of this application. Figure 5 As shown, the methods for testing the density of riprap concrete include:

[0056] S101, fill the rockfill area with rockfill body, and place multiple sensing electrodes at different positions in the rockfill body;

[0057] S102, pour concrete into the rockfill area and use inductive electrodes to collect the resistance value between its two inductive terminals.

[0058] S103, the detection module is used to convert the resistance value into a resistance level and obtain the change curve of the resistance level during the concrete pouring process;

[0059] S104, obtain the first signal L from the resistance value level change curve. A Second signal L B and the third signal L C First signal LA The resistance level is the value when the sensing electrode is not in contact with the concrete, and the second signal L is... B The resistance level is at the moment the sensing electrode just contacts the concrete, and the third signal L C The resistance level after the sensing electrode has made stable contact with the concrete;

[0060] S105, according to the first signal L A Second signal L B and the third signal L C The magnitude relationship and the third signal L C The values ​​of these factors together determine the density of the concrete.

[0061] Converting resistance values ​​to resistance value increments amplifies the change in resistance, facilitating calculations and improving detection accuracy. The first signal L is then located within the resistance value increment curve. A Second signal L B and the third signal L C The corresponding points can be used to determine each stage of concrete pouring. By comparing the first signal L... A Second signal L B and the third signal L C The magnitude relationship between the two signals can rule out problems with the sensing electrode and avoid affecting accuracy. Once it is confirmed that the sensing electrode is working properly, the accuracy is then determined by judging the third signal L. C The numerical value of the signal determines the density of the concrete. Concrete density includes fully compacted and partially compacted concrete. Fully compacted and partially compacted concrete correspond to the third signal L. C Different numerical ranges. Based on the above ideas, this application provides two different methods for determining the density of dense concrete, as detailed below:

[0062] Example 1

[0063] When the first signal L A >Third signal L C > Second signal L B And the third signal L C When L ∈ [0.65L, 0.80L], the concrete density at the location of the sensing electrode is completely dense; when the first signal L A >Third signal L C > Second signal L B And the third signal L C When L ∈ (0.80L, 0.90L), the concrete density at the location of the sensing electrode is partially dense, where the first signal L A ∈(0.90L, 0.98L). Wherein, the first signal L... AThe value is also related to factors such as air humidity, the humidity of the rockfill, and weather. For example, on a rainy day, rainwater adhering to the sensing end of the sensing electrode will cause the first signal L to... A The value may decrease or fluctuate.

[0064] As described above, the concrete pouring process includes three stages: before the induction electrode contacts the concrete, during contact with the concrete, and after contact with the concrete. The "jump" that occurs during concrete pouring, i.e., the first signal L... A >Third signal L C > Second signal L B This confirms that the sensing electrode is functioning normally and has not been damaged. When the third signal L... C The larger the value, the greater the equivalent resistance of the concrete between the first sensing terminal B1 and the second sensing terminal B2 of the sensing electrode, the higher the proportion of air, and the worse the density of the concrete; conversely, the smaller the value, the better the density. Furthermore, the third signal L... C When L ∈ [0.65L, 0.80L], the concrete density at the location of the sensing electrode is completely dense, and the third signal L C The conclusion that the concrete density at the location of the sensing electrode is partially dense when ∈ (0.80L, 0.90L) is derived from a large number of experiments.

[0065] For example, the resistance of the first resistor R1 is 44.83 times that of the second resistor R2, and a 12-bit analog-to-digital converter (ADC) with a resolution of 2... 12 =4096. From formula (1), we know that the first signal L... A for:

[0066]

[0067] When the resistance of the first resistor R1 is 44.83 times that of the second resistor R2, and the resistance accuracy error is 1%, the first signal L... A The value is 4006.626, at which point the first signal L... A The upper limit for ADC testing is approximately 90, slightly exceeding the resistor accuracy error. This setting helps determine if the circuit is functioning correctly; if properly connected, the first signal L... A It should be 4007; if the circuit is open, then the first signal L A It should be 4096; a difference of 90 will ensure the first signal L. A When the reading is 4096, it must be due to an open circuit. On the other hand, by leaving only a 90-degree difference as the electrode detection range, the remaining range of 0 to 4007 can be used as an effective reading range, thereby improving the measurement accuracy of the device.

[0068] Based on the above conclusions, a self-test can be performed on the equipment before testing the concrete density to determine whether each sensing electrode is functioning properly. (Reference) Figure 2-3A When the sensing electrode 110 is electrically connected to the detection module, the first resistor R1 and the second resistor R2 are connected in series, and the equivalent resistance R of the concrete is... HSCC The parallel connection ensures that a stable and valid reading can be obtained before the concrete comes into contact with the first sensing terminal B1 and the second sensing terminal B2 of the induction electrode. This reading can be used to determine if the circuit is functioning correctly. When the resistance of the first resistor R1 is 15 to 50 times that of the second resistor R2, the first signal L is measured. A ∈(0.90L, 0.98L]; when the first signal L A When the value is L, it indicates that the riprap concrete compaction testing device has experienced an open circuit; when the first signal L... A If the value is close to 0, it indicates that the circuit paved concrete compaction testing device has short-circuited.

[0069] Example 2

[0070] When the third signal L C ∈[0.65L, 0.80L] and the third signal L C With the second signal L B When the difference is in the range of 0.10L-0.30L, the concrete at the measuring point is completely compacted; when the third signal L... C ∈[0.80L, 0.90L] and the third signal L C With the second signal L B When the difference is in the range of 0.35L-0.40L, the concrete at the measuring point is completely compacted.

[0071] During the concrete pouring process, the "jump" in the resistance level change curve implies a precondition of the third signal L. C It must be greater than the second signal L. B The third signal L C With the second signal L B The difference represents the increase in value from point B to point C, indicating a "jump" phenomenon, meaning the sensing electrode at the corresponding location is operating normally. When the third signal L... C With the second signal L B When the difference is too high, the sensing electrode may malfunction; for example, the third signal L... C The temperature rose to around point A, indicating a possible malfunction in the sensing electrode. Using the third signal L... C With the second signal L B The method of determining the density of concrete by combining the values ​​of the third signal and other signals has the advantages of being simple and having high detection accuracy.

[0072] Figure 6This is a schematic diagram of on-site testing of concrete density according to an embodiment of this application; Figure 7 This is a schematic diagram showing the change in resistance levels of multiple sensing electrodes in a field according to an embodiment of this application. Figure 6 As shown, multiple induction electrodes were placed at different locations between the riprap bodies, and concrete was poured. Signals were obtained using the induction electrodes. Figure 7 The curves showing the variation of multiple resistance values ​​are shown in the image. Figure 7 It can be seen that the resistance values ​​of each sensing electrode change at different times, indicating that the sensing electrodes at different locations come into contact with the concrete at different times, but the stages of change are roughly the same, all showing a "jump" before gradually stabilizing.

[0073] In such Figure 7 Among the multiple curves shown, the lowest values ​​are concentrated between 2812 and 3047, and the stable values ​​are concentrated between 3093 and 3117. The resolution of the ADC used in this test was 2. 12 =4096, then it corresponds to the second signal L B In the range [0.68L, 0.74L], the corresponding third signal L C Within the range of [0.75L, 0.77L], using the above method, and through multiple experiments to obtain various resistance value variation curves, it is concluded that: when the third signal L... C When L ∈ [0.65L, 0.80L], the concrete at the location of the sensing electrode is completely compacted; when the third signal L C The concrete at the location of the induction electrode in the range of (0.80L, 0.90L) represents a partially dense area.

[0074] According to one embodiment of this application, the concrete in this application includes self-compacting concrete (HSCC) and normal concrete. This application utilizes the characteristic of concrete as a poor conductor to detect its density. Therefore, regardless of the type of concrete, as long as it has weak conductivity, its density can be detected using the apparatus and method of this application, and there is no limitation herein.

[0075] In summary, this application utilizes a riprap concrete density testing device to obtain a resistance level change curve during concrete pouring, and then uses the first signal L in the resistance level change curve to... A Second signal L B and the third signal L C The magnitude relationship determines whether the corresponding sensing electrode is abnormal. If an abnormality is found, the sensing electrode is shielded and no longer participates in the detection. A self-test function is performed before detection to rule out abnormal sensing electrodes. When the sensing electrode is working normally, the third signal L... C The numerical value determines the density of concrete. The third signal L is used. CThe numerical value can determine the density level of concrete, making the test results more precise and providing great guidance for the next stage of construction.

[0076] The above embodiments are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art can make various changes and modifications without departing from the scope of this application. Therefore, all equivalent technical solutions should also fall within the scope of this application.

Claims

1. A device for testing the density of riprap concrete, characterized in that, include: One or more sensing electrodes are disposed between the rockfill bodies. Each sensing electrode includes two sensing terminals for acquiring the resistance change between the two sensing terminals. The sensing electrode includes a first resistor R1 and an equivalent resistance disposed between the two sensing terminals, i.e., a third resistor R. HSCC ; The detection module, electrically connected to the sensing electrode, forms an electrode group. The detection module includes a second resistor R2, one end of which is electrically connected to a power supply, and the other end is electrically connected to one end of a first resistor R1. The other end of the first resistor R1 is grounded. The first resistor R1 and the third resistor R... HSCC in parallel; An analog-to-digital converter is used to convert the first resistor R1 and the third resistor R HSCC The voltage values ​​at both ends are converted into resistance values ​​to obtain a curve showing the change in resistance values ​​during concrete pouring. as well as The data processing module is electrically connected to the detection module, and the data processing module acquires the first signal L from the change curve of the resistance value level. A Second signal L B and the third signal L C And according to the first signal L A Second signal L B and the third signal L C The magnitude relationship and the third signal L C The values ​​of L and L together determine the density of the concrete, wherein the first signal L A The resistance level is the value when the sensing electrode is not in contact with the concrete, and the second signal L is... B The resistance level is at the moment the sensing electrode just contacts the concrete, and the third signal L is... C The resistance value is the level after the inductive electrode has been in stable contact with the concrete.

2. The riprap concrete density testing device according to claim 1, characterized in that, The resistance level of the sensing electrode when it is not in contact with the concrete is: ； Among them, ADC AIN1 Let R1 be the first resistor, R2 be the second resistor, and L be the maximum value of the resistance level between the sensing terminals.

3. The riprap concrete density testing device according to claim 1, characterized in that, The resistance level of the sensing electrode when it first contacts the concrete or after it has been in stable contact with the concrete is: ； Among them, ADC AIN1 The resistance values ​​between the sensing terminals are in the range, where R1 is the first resistor, R2 is the second resistor, and R... HSCC L is the equivalent resistance between the two sensing terminals, where L is the maximum value of the resistance range.

4. The riprap concrete density testing device according to claim 1, characterized in that, The resistance of the first resistor R1 is 10-50 times the resistance of the second resistor R2.

5. The riprap concrete density testing device according to claim 1, characterized in that, Further includes: A data acquisition module, which is electrically connected to multiple electrode groups connected in series, is used to collect the resistance values ​​of each of the sensing electrodes in the electrode groups and send the collected resistance values ​​to the data processing module.

6. The riprap concrete density testing device according to claim 1, characterized in that, Further includes: One or more temperature sensors are installed between the rockfill bodies to detect the temperature value during the concrete pouring process and send the temperature value to the data processing module. The data processing module is based on the first signal L A Second signal L B and the third signal L C The magnitude relationship, the third signal L C The density of concrete is determined by the numerical value of the concrete and the temperature value.

7. The riprap concrete density testing device according to claim 1, characterized in that, The equivalent width of the two sensing ends is 2mm-3mm, the equivalent length is 20mm-30mm, and the distance between the two sensing ends is 10mm-20mm.

8. A method for testing the density of riprap concrete, characterized in that, The method for performing riprap concrete density testing based on the riprap concrete density testing device according to any one of claims 1-7, the method comprising: A rockfill body is constructed in the rockfill area, and multiple induction electrodes are placed at different positions within the rockfill body. Concrete was poured into the rockfill area, and the resistance change between its two sensing terminals was collected using inductive electrodes. The voltage value is converted into a resistance level using a detection module, and the change curve of the resistance level is obtained during the concrete pouring process. The first signal L is obtained from the curve of resistance value variation. A Second signal L B and the third signal L C The first signal L A The first signal is the resistance level when the sensing electrode is not in contact with the concrete; the second signal LB is the resistance level when the sensing electrode just comes into contact with the concrete; and the third signal LC is the resistance level after the sensing electrode has made stable contact with the concrete. Based on the first signal L... A Second signal L B and the third signal L C The magnitude relationship and the third signal L C The values ​​of these factors together determine the density of the concrete.

9. The method according to claim 8, characterized in that, When the first signal L A >Third signal L C > Second signal L B And the third signal L C When the density is ∈ [0.65L, 0.80L], the concrete density at the location of the sensing electrode is completely dense.

10. The method according to claim 8, characterized in that, When the first signal L A >Third signal L C > Second signal L B And the third signal L C When ∈ (0.80L, 0.90L), the concrete density at the location of the sensing electrode is partially dense.

11. The method according to claim 8, characterized in that, The first signal L A ∈ (0.90L, 0.98L).

12. The method according to claim 11, characterized in that, When the first signal L A When the value is L, it is determined that the riprap concrete compaction testing device has experienced an open circuit; when the first signal L... A When the value approaches 0, it is determined that the riprap concrete density testing device has short-circuited.

13. The method according to claim 8, characterized in that, The concrete includes self-compacting concrete and normal concrete.

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