Rapid detection equipment and method for silt content in sandy soil based on optoelectronic detection

Abstract

The present invention discloses a rapid detection device and method for silt content in sandy soil based on optoelectronic detection. Based on the principle that the sedimentation velocities of sandy soil particles with different particle sizes are different, by measuring the light transmittance of turbid liquids with different silt contents, a linear relationship between various silt contents in sandy soil and light transmittance is established. By means of the light transmittance and light scattering rate of the slurry mixture, the silt content is rapidly detected, and the silt content value corresponding to the light transmittance can be accurately obtained. It is applicable to scenarios such as sand washing plants, river sand excavation sites, and river sand storage sites where rapid on-site and real-time detection of the silt content in sandy soil is required. The present invention ensures the test accuracy, can improve the efficiency, save time, and reduce costs.

Description

Technical Field

[0001] The present invention belongs to the field of on-site rapid detection of geotechnical engineering, and particularly relates to a rapid detection device and method for silt content in sandy soil based on optoelectronic detection, which is applicable to the rapid detection of silt content in sandy soil on site. Background Art

[0002] Sandy soil is an important component of concrete and mortar, and is widely used in road construction, infrastructure filling, backfill soil, and as an aggregate for building materials. The silt content directly affects the performance of products. According to the Standard for Quality and Inspection Methods of Sand and Gravel for Ordinary Concrete, the silt content is the percentage of the weight of particles with a particle size less than 0.075 mm in the total mass of the sample. The traditional silt content tests for sandy soil are mainly the standard method and the siphon method.

[0003] During the production process of sand and gravel quarries and sand washing plants, there are strict requirements for the silt content in sandy soil, which directly affects the quality of sandy soil aggregates and the performance of the final products. Excessive silt content will reduce the strength and durability of building materials such as concrete and asphalt, and may lead to engineering quality problems. Therefore, these places need to regularly test the silt content of sandy soil aggregates to ensure that they meet the requirements of relevant engineering standards and specifications.

[0004] However, the currently widely used traditional drying and weighing method, through sampling - labeling - transporting to the laboratory - drying - weighing - rinsing - drying - weighing, takes at least 1 - 2 working days, which is time-consuming, inefficient, and costly. As a result, it is impossible to timely determine whether the excavated sand in the sand and gravel quarry can be directly used for resource utilization or whether it is worth washing, and all the mined sandy soil can only be transported to the sand washing plant for washing, seriously wasting transportation capacity, reducing the output rate, and increasing costs. At the same time, in the sand washing plant, to test the silt content of sandy soil with unknown sources to judge the necessity of washing, or to detect the silt content of the washed sandy soil to judge whether it meets the requirements, or to sample and send it for inspection or build a self - built laboratory for testing as described above, all require high time and economic costs.

[0005] In order to improve efficiency, save time, and reduce costs, a rapid detection device and method for silt content in sandy soil based on optoelectronic detection are proposed. Based on the principle that the sedimentation velocities of sandy soil particles with different particle sizes are different, the silt content is rapidly detected by means of the light transmittance and light scattering rate of the slurry mixture. Summary of the Invention

[0006] To solve the problems in the background art, the present invention proposes a rapid detection device and method for silt content in sandy soil based on optoelectronic detection. The present invention is applicable to the rapid detection of silt content on site such as in sand washing plants and river sand excavation.

[0007] The object of the present invention is achieved by the following technical solutions: A rapid detection device for the mud content of sandy soil based on photoelectric detection, comprising an LED light source, a sampling bottle, a sample chamber, a transmitted light detector, a vertically scattered light detector, and a microprocessor;

[0008] The sampling bottle is used for holding water and sampling sandy soil;

[0009] The sample chamber is used for placing the sampling bottle; Three round holes are opened in the sample chamber, namely an incident light channel, a transmitted light channel, and a vertically scattered light channel;

[0010] The LED light source is aligned with the incident light channel;

[0011] Both the vertically scattered light detector and the transmitted light detector include a group of photoresistors. The centers of the photoresistors of the two are on the same horizontal plane as the corresponding round holes in the sampling chamber. The vertically scattered light detector corresponds to the vertically scattered light channel, and the transmitted light detector corresponds to the transmitted light channel. The connecting lines between the two photoresistors and the corresponding round holes are perpendicular to each other and the distances from the round holes to the corresponding photoresistors are equal;

[0012] The microprocessor is used to receive the light intensity signals collected by the vertically scattered light detector and the transmitted light detector when the sandy soil settles below the measurement point, and calculate the mud content of the sandy soil according to the initial mass of the sandy soil.

[0013] Further, a filter is installed between the LED light source and the sample chamber. The LED light source, the filter, the sample chamber, and the transmitted light detector are centered and aligned on the same horizontal plane and arranged linearly.

[0014] Further, one end of the photoresistor is connected to a signal amplifier, and the other end is connected to the positive pole of the power supply. The other end of the signal amplifier is connected to an analog-to-digital converter; The analog-to-digital converter is used to receive the vertically scattered light detector and the transmitted light detector and convert the electrical signal into a digital signal, which is sent to the microprocessor for processing.

[0015] Further, the device also includes a display and interactive buttons. The display and the interactive buttons are arranged on the upper part of the top surface of the device body. The display is on the top and the interactive buttons are below; The interactive buttons include four function buttons: "On / Off", "Measure", "Tare", and "Clear". "On / Off" controls the start and stop of the whole device, "Measure" is for the photoelectric detection function, "Tare" is for the weighing platform function, and "Clear" clears all data information on the display screen.

[0016] Further, the weighing platform is located at the center of the top surface of the device body and is used to measure the mass of the sample.

[0017] On the other hand, the present invention also provides a rapid detection method for the mud content of sandy soil based on photoelectric detection. The steps of the method are as follows:

[0018] (1) Fill the sampling bottle with water up to the calibration line and weigh it.

[0019] (2) Sample sand and soil through a sampler, place it in the sampling bottle and weigh it. Record the sample mass as m. After tightening the bottle cap, shake the bottle body for a period of time to mix the sand and soil with water.

[0020] (3) Place the sampling bottle in the sample chamber. Calculate the sedimentation time required for particles of different particle sizes according to Stokes' law. When all particles with a particle size above 0.075 mm have settled below the measurement point, only mud particles remain suspended in the solution at the measurement point. At this time, t 0.075 The measured light attenuation is converted to the required mud content; the required time point for capturing the photoelectric signal of the mud slurry, where t 0.075 The calculation formula is as follows:

[0021] t 0.075 = 9·μ·h / (2·(ρ p - ρ f )·g·5.625·10 -9 )

[0022] In the formula, t 0.075 is the time required for particles larger than 0.075 mm to descend a height h in water, with the unit of s. μ is the dynamic viscosity of water, h is the vertical distance from the calibration line of the sampling bottle to the center of the photoresistor, ρ p is the sand particle density, and the sand particles are 2650 kg / m 3 , ρ f is the density of water, and g is the acceleration due to gravity;

[0023] The mud content is calculated according to the following formula:

[0024] w c = (a·I s / I t + b) / m

[0025] In the formula, w c is the mud content, I s is the vertical scattered light intensity, I t is the transmitted light intensity, m is the initial mass of the sand and soil, and a and b are calculation parameters.

[0026] The present invention has the following advantages and positive effects:

[0027] 1) By testing the light transmittance of turbid liquids with different mud contents, the present invention establishes a linear relationship between the mud content of various sands and the light transmittance, and can accurately obtain the mud content value corresponding to the light transmittance.

[0028] 2) The device of the present invention is portable and the measurement method is fast (the device size is about 20 cm, and the test time is within 2 minutes), which is very suitable for scenarios such as sand washing plants, river sand excavation sites, and river sand storage sites that require on-site and real-time rapid detection of the mud content in sandy soil.

[0029] 3) According to Stokes' law, the present invention automatically measures after all particles with a particle size above 0.075 mm have fallen below the measurement point, which can ensure that the particle size of the turbid liquid particles in the test part is within 0.075 mm, and the test accuracy is ensured in principle. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural diagram of each component of the device of the present invention;

[0031] Figure 2 It is a schematic circuit diagram of the photoelectric detection module of the present invention;

[0032] In the figure: 1 - device main body, 2 - light shield, 3 - LED light source, 4 - filter, 5 - sample chamber, 6 - transmitted light detector, 7 - vertical scattered light detector, 8 - analog-to-digital converter, 9 - microprocessor, 10 - power supply, 11 - display, 12 - interaction button, 13 - weighing platform, 14 - sampling bottle, 15 - sampler. DETAILED DESCRIPTION OF THE INVENTION

[0033] The following further details the specific embodiments of the present invention with reference to the accompanying drawings.

[0034] As Figure 1 and Figure 2 shown, the present invention provides a rapid detection device for the mud content in sandy soil based on photoelectric detection, including a device main body, a light shield, an LED light source, a filter, a sample chamber, a transmitted light detector, a vertical scattered light detector, an analog-to-digital converter, a microprocessor, a power supply, a display, an interaction button, a weighing platform, a sampling bottle, and a sampler.

[0035] The device main body and the light shield are made of opaque plastic material. One long side of the light shield is connected to the device main body through a hinge, and the inside is the sample chamber after being opened.

[0036] The LED light source, the transmitted light detector, the vertical scattered light detector, the analog-to-digital converter, the microprocessor, and the power supply are connected by circuits and are all arranged inside the device main body. The LED light source, the filter, the sample chamber, and the transmitted light detector are centered and aligned in sequence on the same horizontal plane inside the device and are arranged linearly;

[0037] The LED light source is monochromatic light and is connected to the power supply;

[0038] The sample chamber conforms to the size of the sampling bottle, and there are three round holes with a diameter of 1 cm at a distance of 10 cm from the bottom surface of the sample chamber, which are the incident light channel, the transmitted light channel, and the vertical scattered light channel respectively;

[0039] Both the vertical scattered light detector and the transmitted light detector include a group of photosensitive resistors and signal amplifiers. The centers of the photosensitive resistors of the two are on the same horizontal plane as the openings of the sampling chamber. The connecting lines between the two photosensitive resistors and the corresponding round holes are perpendicular to each other and the distances from the round holes to the corresponding photosensitive resistors are equal. The vertical scattered light detector corresponds to the vertical scattered light channel, and the transmitted light detector corresponds to the transmitted light channel; One end of the photosensitive resistor is connected to the signal amplifier, the other end is connected to the positive pole of the power supply, and the other end of the signal amplifier is connected to the analog-to-digital converter.

[0040] The analog-to-digital converter is used to receive the vertical scattered light detector and the transmitted light detector and convert the electrical signal into a digital signal, and then transmit it to the microprocessor for processing;

[0041] The microprocessor has built-in algorithms, which can process and calculate the digital signal, and can also realize functions such as controlling the measurement time and recording data;

[0042] The power supply is installed on the upper part of the bottom surface of the equipment main body and can be replaced or directly charged for use;

[0043] The display and the interaction buttons are arranged on the upper part of the top surface of the equipment main body, with the display on the top and the interaction buttons on the bottom; The interaction buttons include four function buttons: "On / Off", "Measure", "Tare", and "Clear". "On / Off" controls the start and stop of the entire equipment, "Measure" is the function of the photoelectric detection module, "Tare" is the function of the weighing platform, and "Clear" clears all data information on the display screen;

[0044] The weighing platform is located at the center of the top surface of the equipment main body, is connected in parallel with the photoelectric detection circuit, and shares the same power supply;

[0045] The body of the sampling bottle is made of transparent plastic material, the bottle cap is made of black plastic material, and the body of the bottle is marked with scale lines.

[0046] On the other hand, the present invention also provides a rapid detection method for the mud content of sandy soil based on photoelectric detection. The method steps are as follows:

[0047] First step, press the "On / Off" interaction button and open the light-shielding cover at the same time;

[0048] Second step, remove the bottle cap of the sampling bottle, fill it with water to the scale line, weigh it on the weighing platform and tare it;

[0049] In the third step, hold the sampler and horizontally insert it into the sand pile until it touches the sand. Take out the sampler, insert it into the sampling bottle, shake it until the sample drops, and weigh it. Record the sample mass as m. After tightening the bottle cap, shake the bottle for 30 s to 45 s to mix the sand and water evenly;

[0050] In the fourth step, place the sampling bottle in the sample chamber, close the light shield, and press the "Measure" button at the same time. Calculate the sedimentation time required for particles of different particle sizes according to Stokes' law. When all particles with a particle size above 0.075 mm (particles with a particle size above 0.075 mm are sand particles, and particles with a particle size below 0.075 mm are mud particles) settle below the measurement point (t 0.075 / s), only mud particles remain suspended in the solution at the measurement point. At this time (t 0.075 / s), the light attenuation measured can be used to convert the required mud content. The time point for capturing the photoelectric signal of the required mud slurry, where t 0.075 The calculation formula is as follows:

[0051] t 0.075 = 9·μ·h / (2·(ρ p -ρ f )·g·5.625·10 -9 )

[0052] In the formula, t 0.075 is the time required for particles larger than 0.075 mm to fall a height h in water, μ is the dynamic viscosity of water, h is the vertical distance from the calibration line of the sampling bottle to the center of the photoresistor, ρ p is the density of sand particles (sand particles can generally be taken as 2650 kg / m 3 ), ρ f is the density of water, and g is the acceleration due to gravity.

[0053] In the fifth step, the mass of mud particles (g) and the mud content (%) are displayed on the screen. Press the "Record" button to record the results. The mud content is calculated according to the following formula:

[0054] w c = (a·I s / I t +b) / m

[0055] In the formula, w c is the mud content, I s is the intensity of vertically scattered light, I t is the intensity of transmitted light, m is the initial mass of sand, and a and b are calculation parameters. Among them, m is the average sampling mass of the sampler during calibration, and the mass can also be calculated manually according to the sample mass measured in the second step.

[0056] Example:

[0057] The calculation process of a specific example provided by the present invention is as follows:

[0058] First step, press the "On / Off" interaction button -12 and simultaneously open the light shield -2;

[0059] Second step, remove the cap of the sampling bottle, fill it with water up to the calibration line, and weigh it on the weighing platform -13 and tare;

[0060] Third step, hold the sampler -15 and horizontally insert it into the sand pile until the hand touches the sand, take out the sampler and insert the sampler into the sampling bottle -14 and shake it until the sample drops, and weigh it. The sample mass is 20 g. After tightening the cap, shake the bottle body for 30 s to 45 s;

[0061] Fourth step, put the sampling bottle into the sample chamber -5, close the light shield, and simultaneously press the "Measure" interaction button -12; calculate the sedimentation time required for particles of different particle sizes according to Stokes' law. When all particles with a particle size above 0.075 mm (particles with a particle size above 0.075 mm are sand particles, and particles with a particle size below 0.075 mm are mud particles) settle below the measurement point (t 0.075 / s), only mud particles are suspended in the solution at the measurement point. At this time (t 0.075 / s), the light attenuation measured can be used to convert the required mud content. The required time point for capturing the photoelectric signal of the mud slurry, where t 0.075 The calculation formula is as follows:

[0062] t 0.075 = 9·μ·h / (2·(ρ p -ρ f )·g·5.625·10 -9 )

[0063] In the formula, t 0.075 is the time required for particles larger than 0.075 mm to fall a height h in water, μ is the dynamic viscosity of water, h is the vertical distance from the calibration line of the sampling bottle to the center of the photoresistor, ρ p is the density of sand particles (sand particles can generally be taken as 2650 kg / m 3 ), ρ f is the density of water, g is the acceleration due to gravity, and it is calculated that t 0.075 ≈4 s.

[0064] After 4 s, they will all settle below the plane of the photodetectors -6 and 7 in water. The system automatically times and captures the photoelectric signal after 4 s during measurement, converts the electrical signal into a digital signal through the analog - digital converter -8, and the microprocessor -9 processes the data;

[0065] Fifth step, the screen displays the mass of mud particles (g) and the mud content (%). Press the "Record" button to record the results. The mud content is calculated according to the following formula:

[0066] w c = (a·I s / I t + b) / m

[0067] wherein, w c is the mud content, I s is the intensity of vertically scattered light, I t is the intensity of transmitted light, m is the initial mass of sandy soil, a and b are calculation parameters, mainly obtained through laboratory calibration. By measuring I s / I t of the standard mass mud particle suspension for multiple times, a = 0.0011 and b = 0.0292 are obtained. Wherein m is the average sampling mass of the sampler during calibration, and the mass can also be manually calculated according to the sample mass measured in the second step.

[0068] Step 6: The display - 11 shows that the mass of mud particles is 0.4772 g and the mud content is 2.3%. Press the "Record" interaction button - 12 to record the result. The mud content can also be manually calculated according to the mass of mud particles and the actual weighed weight of sandy soil.

[0069] The above embodiments are used to explain the present invention, rather than to limit the present invention. Any modification and change made to the present invention within the spirit and scope of the claims of the present invention fall within the protection scope of the present invention.

Claims

1. A method for rapid detection of sand mud content based on photoelectric detection, characterized in that: The method is implemented based on a rapid detection device for sand and soil mud content using photoelectric detection, the device comprising an LED light source, a sampling bottle, a sample chamber, a transmission light detector, a vertical scattered light detector and a microprocessor; The sampling bottle is used to hold water and perform sand sampling; The sample chamber is used to place the sampling bottle; the sample chamber has three circular holes, which are the incident light channel, the transmitted light channel and the vertical scattered light channel; The LED light source is aligned with the incident light channel; The vertical scattered light detector and the transmitted light detector each comprise a group of photoresistors, the centers of the two photoresistors are respectively on the same horizontal plane as the corresponding circular holes of the sampling chamber, the vertical scattered light detector corresponds to the vertical scattered light channel, the transmitted light detector corresponds to the transmitted light channel, the lines connecting the two photoresistors and the corresponding circular holes are perpendicular to each other, and the distances from the circular holes to the corresponding photoresistors are equal; The microprocessor is used to receive the light intensity signal collected by the vertical scattered light detector and the transmitted light detector when the sand settles below the measuring point, and calculate the mud content of the sand according to the initial mass of the sand; The steps of the method are as follows: (1) Fill the sampling bottle with water to the mark and weigh it; (2) Take a sample of sand and soil through a sampler, place it in a sampling bottle and weigh it. The sample mass is recorded as m. After tightening the bottle cap, shake the bottle for a while to mix the sand and water. (3) Place the sampling bottle in the sample chamber and calculate the sedimentation time required for particles of different sizes according to Stokes' law. When all particles with a diameter of 0.075 mm or larger settle below the measuring point, only mud particles are suspended in the solution at the measuring point. At this time, t 0.075 The measured light attenuation is converted into the required mud content; the required mud photoelectric signal capture time point, where t 0.075 The calculation formula is as follows: t 0.075 =9·μ·h / (2·(ρ p -r f )·g·5.625·10 -9 ) Where, t 0.075 is the time required for particles larger than 0.075 mm to fall from a height of h in water, in seconds, μ is the dynamic viscosity of water, h is the vertical distance from the scale line of the sampling bottle to the center of the photoresistor, ρ p is the density of sand particles, which is 2650kg / m 3 , ρ f is the density of water, g is the acceleration due to gravity; The mud content is calculated according to the following formula: w c =(a·I s / I t +b) / m In the formula, w c is the mud content, I s is the vertical scattered light intensity, I t is the transmitted light intensity, m is the initial mass of sand, and a and b are calculation parameters.

2. The method for rapid detection of sand content based on photoelectric detection according to claim 1 is characterized in that: A filter is installed between the LED light source and the sample chamber, and the LED light source, the filter, the sample chamber, and the transmission light detector are centrally aligned and linearly arranged on the same horizontal plane.

3. The method for rapid detection of sand content based on photoelectric detection according to claim 1 is characterized in that: One end of the photoresistor is connected to the signal amplifier, and the other end is connected to the positive pole of the power supply. The other end of the signal amplifier is connected to the analog-to-digital converter; the analog-to-digital converter is used to receive the vertical scattered light detector and the transmitted light detector and convert the electrical signal into a digital signal, which is then transmitted to the microprocessor for processing.

4. The method for rapid detection of sand mud content based on photoelectric detection according to claim 1 is characterized in that: The device also includes a display and interactive buttons, which are arranged on the upper part of the top surface of the device body, with the display on the top and the interactive buttons on the bottom; the interactive buttons include four functional buttons: "on / off", "measurement", "peel", and "clear", "on / off" controls the start and close of the entire device, "measurement" is a photoelectric detection function, "peel" is a weighing platform function, and "clear" clears all data information on the display screen.

5. The method for rapid detection of sand mud content based on photoelectric detection according to claim 4 is characterized in that: The weighing platform is located at the center of the top surface of the equipment body and is used to measure the mass of the sample.

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