Dry density rapid detection device

Abstract

The utility model relates to engineering detection technical field, discloses a kind of quick detection device of dry density specifically, to solve the problems such as traditional detection method operation cumbersome, low efficiency, existing radiation risk. Device core includes standard container, weighing sensor, signal conditioning circuit, single-chip microcontroller, hardware proportioning calculator, stable judging module, display screen and ventilation / heating module. Through RFID, container volume V is automatically read, weighing sensor measures soil sample mass m, proportioning calculator calculates dry density ρ=m / V in real time, and the result is output through display screen;Ventilation / heating module accelerates moisture evaporation, shortens detection time. The device has the advantages of real-time display, simple operation, avoids artificial error, no radiation risk, and is suitable for fine-grained soil, coarse-grained soil and frozen soil detection dry density requirements, etc., and is suitable for water conservancy engineering, such as earth dam filling and embankment engineering, building engineering and other fields of soil compaction quality rapid detection.

Description

Technical Field

[0001] This utility model relates to the field of water conservancy engineering technology, and in particular to dry density detection technology. Background Technology

[0002] In the field of water conservancy engineering technology, the core of quality control for earthwork filling (such as earth dams, dikes, roadbeds, etc.) lies in the compaction degree of the soil material, and dry density is a key indicator for measuring compaction degree (which needs to be converted from wet density and moisture content or directly measured).

[0003] Dry density directly reflects the compaction of soil and is a core parameter for assessing the stability, impermeability, and durability of hydraulic engineering projects (such as earth dams and embankments). Substandard density can lead to soil settlement, seepage, and even dam failure, posing safety hazards. Traditional testing methods are inherently slow (e.g., the ring cutter method requires manual cutting, and the sand cone method requires multiple weighings) and inefficient (each test is time-consuming), making it impossible to adjust compaction parameters (such as the number of compaction passes and moisture content) in a timely manner during construction, easily resulting in rework and resource waste.

[0004] Traditional dry density testing methods (such as the ring sampler method, sand cone method, and water cone method) have significant limitations: the ring sampler method is only suitable for fine-grained soils, and manual operation easily disturbs the soil sample; the sand cone method requires multiple weighings of standard sand, which is cumbersome and inefficient; the nuclear density meter method, although fast, poses a radiation risk and requires frequent calibration. With the development of mechanized and intelligent construction in water conservancy projects, traditional methods can no longer meet the needs of "rapid detection and real-time feedback." Therefore, there is an urgent need to develop an efficient, accurate, and easy-to-operate rapid dry density testing device to adapt to the fast construction pace of modern water conservancy projects. Utility Model Content

[0005] The purpose of this invention is to address the problems in the existing technology by providing a rapid dry density detection device that can detect a wide range of objects, is simple to operate, has high efficiency, poses no radiation risk, and does not require frequent calibration.

[0006] To achieve the above objectives, the dry density rapid detection device of this utility model includes a standard container, a weighing sensor, a signal conditioning circuit, a microcontroller, a proportional calculator, a display screen, and a ventilation module for accelerating the evaporation of moisture from the soil sample; wherein:

[0007] The standard container has a volume V, and an RFID tag storing the volume V information is provided on the surface of the standard container.

[0008] The weighing sensor is used to support the standard container, measure the wet mass m of the soil sample, and output an analog voltage signal;

[0009] The signal conditioning circuit is connected to the weighing sensor and is used to amplify, filter and convert the analog voltage signal into a digital signal;

[0010] The microcontroller is connected to the signal conditioning circuit, the RFID reader 7, the proportional calculator, the display screen, and the ventilation module, respectively, and is used to read the volume V in the RFID tag, control the start and stop of the ventilation module, and receive the digital signal output by the signal conditioning circuit.

[0011] The proportional amplifier is connected to the microcontroller and is used to receive the voltage signal after conditioning by the weighing sensor and the voltage signal of the volume V, calculate the dry density ρ=m / V and output the voltage.

[0012] The display screen is connected to the microcontroller and is used to display the current m / V value and the dry density result after stabilization in real time.

[0013] The signal conditioning circuit includes an HX711 module and a low-pass filter. The HX711 module is connected to the weighing sensor, and the low-pass filter is connected to the HX711 module.

[0014] The electronic control device is also connected to a stability judgment module, which is connected to the proportional arithmetic unit and is used to monitor the stability of the dry density voltage. When the voltage change is less than a threshold, a stability signal is output.

[0015] The stability judgment module includes a voltage comparator, a potentiometer, and an LED indicator. The potentiometer is used to adjust the voltage change threshold, and the LED indicator is used to indicate whether the dry density is stable.

[0016] The ventilation module includes a ventilation box and a miniature axial flow fan; the ventilation box has an air inlet with a dustproof screen on the left side and the axial flow fan is installed on the right side; the axial flow fan is connected to the microcontroller; the ventilation box is used to house the weighing sensor and the standard container.

[0017] It also includes a heating module, which includes a PTC heating element and a temperature sensor; the PTC heating element is disposed inside the ventilation box, and the temperature sensor is connected to the microcontroller. The microcontroller connects to the PTC heating element and the temperature sensor and controls the PTC heating element.

[0018] It also includes a data storage module, which is a MicroSD card module connected to the microcontroller via an SPI interface, and is used to store data such as detection time and dry density value.

[0019] This utility model has the following advantages:

[0020] This invention features a simple structure, facilitating the detection of soil sample dry density and guiding subsequent engineering practices. It is applicable to a wide range of soil types (suitable for fine-grained soil, coarse-grained soil, frozen soil, etc.), requires minimal manual operation, and the soil sample is contained within a container, minimizing disturbance. It also eliminates the need for repeated weighing of standard sand or frequent calibration, posing no radiation risk. It meets the demands for "rapid detection and real-time feedback," aligning with the trend towards mechanized and intelligent construction in water conservancy projects. The standard container surface is equipped with an RFID tag, allowing for easy replacement with standard containers of different volumes to meet diverse measurement needs. Through automatic calculation and display functions, this invention significantly improves detection efficiency, providing immediate data support for construction decisions and ensuring project quality and safety.

[0021] The stability assessment module can send a message indicating that the dry density has stabilized via an LED indicator, making it very easy for operators to identify whether the measurement work can be completed (end after stabilization).

[0022] Ventilation is used to accelerate the soil sample drying process during measurement, improving measurement efficiency. A heating module further accelerates the soil sample drying process, thereby further improving measurement efficiency. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of this utility model.

[0024] Figure 2 This is a schematic diagram of the electrical control structure of this utility model. Detailed Implementation

[0025] like Figure 1 and Figure 2 As shown, the dry density rapid detection device of this utility model includes a standard container 1, a weighing sensor 2, a signal conditioning circuit 3, a microcontroller 4, a proportional calculator 5 (hardware), a display screen 6, and a ventilation module for accelerating the evaporation of moisture from the soil sample; wherein:

[0026] The standard container 1 has a volume V, and there are several standard containers 1, each with a different volume. For each test, a standard container 1 of a suitable size that matches the test task or test plan is selected. An RFID tag storing the volume V information is provided on the surface of the standard container 1.

[0027] The weighing sensor 2 is used to support the standard container 1, measure the wet mass m of the soil sample, and output an analog voltage signal;

[0028] The signal conditioning circuit 3 is connected to the weighing sensor 2 and is used to amplify, filter and convert the analog voltage signal into a digital signal;

[0029] The microcontroller 4 is connected to the signal conditioning circuit 3, the RFID reader 7, the proportional calculator 5, the display screen 6 and the ventilation module respectively, and is used to read the volume V in the RFID tag, control the start and stop of the ventilation module, and receive the digital signal output by the signal conditioning circuit 3.

[0030] The proportional amplifier 5 is connected to the microcontroller 4 and is used to receive the voltage signal (representing m) after conditioning by the weighing sensor 2 and the voltage signal of the volume V, calculate the dry density ρ=m / V and output the voltage.

[0031] The display screen 6 is connected to the microcontroller 4 and is used to display the current m / V value and the dry density result after stabilization in real time.

[0032] This invention features a simple structure, facilitating the detection of soil sample dry density and thus guiding subsequent engineering practices. It can measure a wide range of soil types (suitable for fine-grained soil, coarse-grained soil, frozen soil, etc.), requires minimal manual operation, and the soil sample is placed inside the container, minimizing disturbance. It also eliminates the need for multiple weighings of standard sand or frequent calibration, posing no radiation risk. It meets the demands for "rapid detection and real-time feedback," aligning with the development trend of mechanized and intelligent construction in water conservancy projects. The standard container 1 is equipped with an RFID tag, allowing for easy replacement with standard containers of different volumes to adapt to various measurement needs.

[0033] The standard container 1 is made of metal or plastic, and the RFID tag is an anti-metal RFID tag (such as PCB packaging) with an epoxy resin coating. The weighing sensor 2 is a strain gauge sensor with a range of 50 kg and an accuracy of 0.01 g. The microcontroller 4 has a built-in digital-to-analog converter.

[0034] The signal conditioning circuit 3 includes an HX711 module (24-bit ADC, amplification factor of 128) and a low-pass filter (RC circuit, cutoff frequency of 10Hz). The HX711 module is connected to the weighing sensor 2, and the low-pass filter is connected to the HX711 module.

[0035] The microcontroller 4 is an Arduino Uno or STM32F103C8T6, integrating SPI, ADC, and GPIO interfaces. The RFID reader 7 (such as MFRC522) is connected to the microcontroller 4 via the SPI interface. The proportional amplifier 5 is an AD633 multiplier chip, used to perform m / V division operations.

[0036] The electronic control device is also connected to a stability judgment module 8, which is connected to the proportional arithmetic unit 5 and is used to monitor the stability of the dry density voltage. When the voltage change is less than a threshold, a stability signal is output.

[0037] The stability judgment module 8 includes an LM339 voltage comparator, a potentiometer, and an LED indicator. The potentiometer is used to adjust the voltage change threshold (e.g., ±0.01V), and the LED indicator is used to indicate whether the dry density is stable.

[0038] The stability judgment module 8 can send a stable signal via an LED indicator after the dry density has stabilized, making it very easy for operators to identify whether the measurement work can be ended (end after stabilization).

[0039] The ventilation module includes a ventilation box 9 and a 5V miniature axial flow fan 10. An air inlet with a dust filter 11 is located on the left side of the ventilation box 9, and the axial flow fan 10 is installed on the right side. The axial flow fan 10 is connected to and controlled by the microcontroller 4. The ventilation box 9 is used to house the weighing sensor 2 and the standard container 1. Ventilation accelerates the soil sample drying process during measurement, improving measurement efficiency.

[0040] It also includes a heating module, which includes a PTC heating element 12 (e.g., 50W power) and a temperature sensor 13 (e.g., DS18B20, accuracy ±0.5℃); the PTC heating element 12 is disposed inside the ventilation box 9, and the temperature sensor 13 is connected to the microcontroller 4 via OneWire communication. The microcontroller 4 connects to the PTC heating element 12 and the temperature sensor 13 and controls the PTC heating element 12.

[0041] The heating module further accelerates the soil sample drying process, thereby further improving measurement efficiency.

[0042] It also includes a data storage module, which is a MicroSD card module connected to the microcontroller 4 via an SPI interface, used to store data such as detection time and dry density values. The data storage module uses conventional technology and is not shown in the figure. The data storage module facilitates data recording and storage.

[0043] When using this utility model, follow these steps:

[0044] I. Preparation Stage: Soil Sample Containerization and Equipment Inspection

[0045] Select Standard Container 1: Select a standard container 1 with the corresponding volume according to the type of soil to be tested (fine-grained soil, coarse-grained soil or frozen soil) (e.g., 200cm³ for fine-grained soil, 500cm³ for coarse-grained soil). Ensure that the inner wall of the container is smooth and free of residual soil sample, and that the RFID tag on the surface (anti-metal PCB encapsulation, with an outer epoxy resin coating) is undamaged.

[0046] Collect and fill the sample: Select a representative soil sample from the soil body to be tested (such as the earth dam fill layer or the cross section of the embankment), fill it evenly into standard container 1, and gently tap the outer wall of the container to compact the soil sample, ensuring that the soil sample fills the container and the surface is flush with the container opening (to avoid volume error).

[0047] Equipment initialization check: Confirm that the device power supply (rechargeable lithium battery or external 5V power supply) is connected normally, the dust filter 11 at the air inlet of the ventilation box 9 is not blocked, and the display screen 6 and LED indicator lights are functioning properly. After power is connected, the microcontroller 4 will start automatically and prepare for testing.

[0048] II. Core Detection Stage: Volume Reading and Dry Density Calculation

[0049] 1. Automatically read the volume V of a standard container:

[0050] A standard container 1 containing a soil sample is placed stably on a weighing sensor 2 inside a ventilated enclosure 9. An RFID reader 7 communicates with a microcontroller 4 via an SPI interface, automatically reading the volume V information (e.g., "500cm³") stored on the RFID tag on the container surface. The microcontroller 4 matches the corresponding V value from its built-in volume-voltage correspondence table (which can be created experimentally by the operator and stored in the microcontroller 4's memory), and converts it into an analog voltage signal (e.g., V=500cm³ corresponds to 2.5V) via a DAC (digital-to-analog converter), inputting it to the proportional amplifier 5 (AD633) as a volume parameter.

[0051] 2. Activate the ventilation / heating module to accelerate moisture evaporation:

[0052] The microcontroller 4 outputs a high level via GPIO, triggering the relay of the built-in fan control module of the micro axial flow fan 10 to engage. The 5V micro axial flow fan 10 starts, and the airflow enters from the left air inlet (with dustproof net 11) of the ventilation box 9, flows over the surface of the standard container 1, and accelerates the evaporation of moisture from the soil sample surface.

[0053] To further shorten the testing time, the microcontroller 4 synchronously outputs a high level to activate the relay of the heating control module, and the PTC heating element 12 (50W power) begins heating. Simultaneously, the temperature sensor 13 (DS18B20, accuracy ±0.5℃) monitors the temperature inside the chamber in real time via OneWire communication. When the temperature exceeds 50℃, the microcontroller 4 automatically outputs a low level to shut off the heating element, preventing the soil sample from becoming too dry and affecting testing accuracy.

[0054] 3. Collect soil sample mass and calculate dry density in real time:

[0055] Weighing sensor 2 measures the wet mass m of the soil sample and outputs an analog voltage signal (0~5mV / V) proportional to the mass. This signal is processed by signal conditioning circuit 3:

[0056] First, the signal is amplified and converted into a digital signal by the HX711 module (24-bit ADC, 128x amplification factor);

[0057] The high-frequency noise is then filtered out by a low-pass filter (RC circuit, cutoff frequency 10Hz) before finally being transmitted to the ADC pin of the microcontroller 4.

[0058] The microcontroller 4 converts the digital signal into an analog voltage (e.g., 2.5V for m=500g), inputs it to the hardware proportional amplifier 5 (AD633), performs a division operation with the voltage signal of volume V (ρ=m / V), and outputs a voltage value representing the dry density (e.g., 1V corresponds to 1g / cm³). The display screen, controlled by the microcontroller 4, displays the currently calculated dry density value in real time. The displayed value will continuously change as moisture evaporates during the measurement process until it finally stabilizes.

[0059] III. Results Output and Data Recording

[0060] Stability assessment and results display:

[0061] The stability assessment module 8 (LM339 voltage comparator + potentiometer) monitors the dry density voltage output by the hardware proportional amplifier 5 in real time: the voltage at the previous moment is stored in a capacitor (10μF), and the current voltage is adjusted to a threshold (e.g., ±0.01V) via a potentiometer (10kΩ) to compare with the stored voltage. If the voltage change is less than the threshold, the comparator outputs a high level, triggering an LED indicator to light up (indicating that the dry density is stable). At this time, the microcontroller 4 reads the final dry density voltage value through the ADC, converts it into the actual density value (e.g., 1.85g / cm³), and displays "Dry density: 1.85g / cm³ Stable" on the LCD1602 display screen 6.

[0062] IV. End of Detection and Data Storage:

[0063] After the test is completed, the microcontroller 4 outputs a low level to shut down the fan (and heating element, if enabled). If the device is equipped with a MicroSD card data storage module (connected via SPI interface), the microcontroller 4 will automatically store the test time (accurate to the second), test location (requires manual input or GPS module assistance), and dry density result (e.g., "2025-06-29 14:30:00 Earth dam filling area 1.85g / cm³") to the SD card to meet the needs of construction data traceability.

[0064] V. Precautions

[0065] Container placement: Ensure that the standard container 1 is placed stably in the center of the weighing sensor 2 to avoid tilting, which could lead to deviations in mass measurement.

[0066] Heating control: In heating mode, close attention should be paid to the feedback from temperature sensor 13 to prevent the temperature from exceeding 50℃ (decomposition of organic matter in soil samples will affect the accuracy of dry density).

[0067] Cleaning and maintenance: Clean the residual soil sample in standard container 1 after each test.

[0068] Through the above steps, this device can quickly complete dry density testing (heating mode), providing rapid data support for engineering construction and ensuring compaction quality and engineering safety.

[0069] The above embodiments are only used to illustrate and not limit the technical solutions of this utility model. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the utility model without departing from the spirit and scope of the utility model. Any modifications or partial substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A rapid dry density detection device, characterized in that, It includes a standard container, a weighing sensor, a signal conditioning circuit, a microcontroller, a proportional controller, a display screen, and a ventilation module for accelerating soil moisture evaporation; among which: The standard container has a volume V, and an RFID tag storing the volume V information is provided on the surface of the standard container. The weighing sensor is used to support the standard container, measure the wet mass m of the soil sample, and output an analog voltage signal; The signal conditioning circuit is connected to the weighing sensor and is used to amplify, filter and convert the analog voltage signal into a digital signal; The microcontroller is connected to the signal conditioning circuit, RFID reader, proportional calculator, display screen and ventilation module respectively, and is used to read the volume V in the RFID tag, control the start and stop of the ventilation module, and receive the digital signal output by the signal conditioning circuit. The proportional amplifier is connected to the microcontroller and is used to receive the voltage signal after conditioning by the weighing sensor and the voltage signal of the volume V, calculate the dry density ρ=m / V and output the voltage. The display screen is connected to the microcontroller and is used to display the current m / V value and the dry density result after stabilization in real time.

2. The rapid dry density detection device according to claim 1, characterized in that: The signal conditioning circuit includes an HX711 module and a low-pass filter. The HX711 module is connected to the weighing sensor, and the low-pass filter is connected to the HX711 module.

3. The rapid dry density detection device according to claim 1, characterized in that: The electronic control device is also connected to a stability judgment module, which is connected to the proportional arithmetic unit and is used to monitor the stability of the dry density voltage. When the voltage change is less than a threshold, a stability signal is output. The stability judgment module includes a voltage comparator, a potentiometer, and an LED indicator. The potentiometer is used to adjust the voltage change threshold, and the LED indicator is used to indicate whether the dry density is stable.

4. The rapid dry density detection device according to claim 1, characterized in that: The ventilation module includes a ventilation box and a miniature axial flow fan; the ventilation box has an air inlet with a dustproof screen on the left side and the axial flow fan is installed on the right side; the axial flow fan is connected to the microcontroller; the ventilation box is used to house the weighing sensor and the standard container.

5. The rapid dry density detection device according to claim 4, characterized in that: It also includes a heating module, which includes a PTC heating element and a temperature sensor; the PTC heating element is disposed inside the ventilation box, and the temperature sensor is connected to the microcontroller. The microcontroller connects to the PTC heating element and the temperature sensor and controls the PTC heating element.

6. The rapid dry density detection device according to claim 5, characterized in that: It also includes a data storage module, which is a MicroSD card module connected to the microcontroller via an SPI interface, for storing detection time and dry density value data.

Images