Soil granularity detection process

Abstract

The invention discloses a soil granularity detection process which comprises the following steps: pouring an air-dried soil sample on a carrier, crushing the air-dried soil sample by using a wood stick, and sieving the crushed air-dried soil sample with the sieving aperture of 2mm to obtain a sieved soil sample; loading the sieved soil sample into a soil particle dispersing device, and physically dispersing the sieved soil sample into particles to obtain a wet soil particle sample; evaporating moisture in the obtained soil particle wet sample to dryness to obtain a soil particle dry sample; adding the obtained soil particle dry sample into a sample pool of a laser particle analyzer, setting parameters of the laser particle analyzer, and measuring the soil particle size in the sample. The method has the advantages of being simple in treatment procedure and convenient to operate, the detection efficiency is high, the whole measurement process consumes less than four hours, more importantly, the soil granularity can be accurately measured, and even acid soil can be smoothly subjected to granularity detection; according to the invention, under the condition of not using any chemical reagent, the bonding force between soil particles is effectively destroyed by using an extremely simple scheme, and the accuracy of a soil particle size measurement result is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of soil detection, and in particular relates to a soil particle size detection process. Background Art

[0002] Soil is composed of different sized particles in different proportions. The relative proportion of each particle size in the soil is called the mechanical composition of the soil, which affects soil moisture, air, heat nutrients and soil type. According to the international soil texture classification standard, soil particle size is divided into three levels, including clay (<0.002mm,%), silt (0.02-0.002mm,%), and sand (2-0.02mm,%). According to the content difference of different texture levels, soil is divided into multiple types, such as loamy sand, sandy loam, loam, and silt loam. When implementing soil testing, soil particle size testing is usually required to facilitate soil evaluation.

[0003] At present, the commonly used classification standards for soil mechanical composition include the Chinese system, the Kachinsky system, the US Department of Agriculture system and the international system. The methods for determining soil mechanical composition are mainly divided into screening method, hydrometer method, pipette method (the corresponding measurement results are currently recognized as the most accurate) and laser method. Among them, the hydrometer method and pipette method have problems such as complex steps, long time consumption and low efficiency.

[0004] In the prior art, document CN112945811A discloses a method for measuring soil particle size using a laser particle size analyzer, comprising the steps of: taking air-dried soil and sieving it; mixing the sifted soil with an appropriate amount of pure water, 30% H2O2, and a defoaming agent, placing it on a magnetic stirrer and stirring it at 80°C, and after bubbles are generated on the surface of the liquid, removing the beaker and cooling it; placing the cooled beaker on a magnetic stirrer and stirring it at 80°C, and after bubbles are generated on the surface of the liquid, removing the beaker and cooling it, and repeatedly repeating the stirring and cooling operations until no bubbles are generated; adding 40g / L sodium dithionite solution and 0.3mol / L sodium acetate solution to the beaker, shaking it overnight, centrifuging it for 8min, and discarding the supernatant; adding 1 0ml10% HCl, place the beaker on a magnetic stirrer, stir at 50℃ until the reaction reaches a static state; after leaving it overnight, measure the pH of the sample, if the pH is greater than 7.5, add 0.5mol / L sodium hexametaphosphate solution, if the pH is between 6.5 and 7.5, add 0.5mol / L sodium oxalate solution, when the pH is less than 5.5, add 0.5mol / L sodium hydroxide solution, and let it stand for 2h; place the sample after standing for 2h on a magnetic stirrer and boil it, keep boiling for 1h, and stir at the same time; remove the beaker and cool it to room temperature; turn on the instrument, check the pipeline connection, clean the instrument, and preheat the instrument; after the instrument is stable, draw the cooled sample into the sample cell, set the laser particle size analyzer parameters, and measure the sample.

[0005] The pre-treatment steps involved in the laser method in the aforementioned literature almost follow the standard treatment steps in this field, and the core is to destroy the cohesive force and organic matter between soil (especially acidic soil) particles by means of chemical reagents such as H2O2 and HCl, as well as a series of processes such as repeated stirring, oscillation, heating and boiling. However, the aforementioned methods must use multiple chemical reagents for repeated operations, which not only has the problem of complex treatment procedures and inconvenient operation, but also has the problem of poor repeatability of measurement results. More importantly, most of the existing methods have little effect on the destruction of the cohesiveness of acidic soil particles (the base ions (K+, Na+, Ca2+, Mg2+, NH4+) adsorbed on the surface of acidic soil colloids are lost by acidogenic ions (H+, Al3+) ions, resulting in a lack of calcium, magnesium and other elements in the acidic soil, and the inability to form a good soil aggregate structure), which is not conducive to the accurate detection of acidic soil particle size. Summary of the invention

[0006] In view of the technical problems mentioned in the background technology, the purpose of the present invention is to provide a soil particle size detection process which has simple procedures, high efficiency, convenient operation and can accurately measure the soil particle size.

[0007] The present invention adopts the following technical solution.

[0008] A soil particle size detection process, comprising the following steps: Step 1, pour the air-dried soil sample on a carrier, crush it with a wooden stick and sieve it, the sieve aperture is 2 mm, and a sieved soil sample is obtained; Step 2, placing the sieved soil sample into a soil particle dispersion device to physically disperse it into particles to obtain a wet soil particle sample; Step 3, evaporating the water in the obtained wet soil particle sample to obtain a dry soil particle sample; Step 4, taking the obtained dry soil particle sample and adding it into the sample pool of the laser particle size analyzer, setting the parameters of the laser particle size analyzer, and measuring the soil particle size in the sample.

[0009] Furthermore, the soil particle dispersion device includes a feed container and a transfer container, the outlet of the feed container is connected to the inlet of the transfer container through a process pipeline, the outlet of the transfer container is connected to the inlet of the transfer container through a return pipeline, and a bidirectional booster pump is provided on both the process pipeline and the return pipeline.

[0010] Furthermore, a plurality of fluid impact parts are arranged at intervals on both the process pipeline and the return pipeline, each of which includes: a pipe joint, a wear-resistant part is arranged in the middle of the inner cavity of the pipe joint, and the wear-resistant part is fixedly connected to the pipe joint through a wear-resistant bracket. When the fluid in the pipeline flows, the fluid continues to flow after flushing the wear-resistant part; or, each fluid impact part adopts a wear-resistant sphere arranged in the inner cavity of the pipeline. Furthermore, the surface of the wear-resistant part is a curved surface.

[0011] Further, the step of starting the soil particle dispersion device to physically disperse the soil particles into particles is as follows: Step 21, after the sieved soil sample is loaded into the feed container, pure water is introduced into the feed container, and then the bidirectional booster pump is controlled (forward operation) to operate at a set pressure of 1 for 1 to 2 hours, and the fluid pressure during this process is not higher than 0.32Mpa; Step 22, control the bidirectional booster pump (forward operation) to operate at set pressure 2 for 0.5 to 1 hours, and the fluid pressure during this process is 0.5 to 0.6 MPa; Step 23, only close the two-way booster pump on the return pipeline, introduce all the fluid in the feed container into the transfer container, then close the two-way booster pump on the process pipeline, introduce pure water into the feed container, and then open the two-way booster pumps of the process pipeline and the return pipeline again (in this process, the two-way booster pump on the process pipeline runs forward, and the two-way booster pump on the return pipeline runs reversely), introduce all the pure water in the feed container into the transfer container, and finally collect the wet sample of soil particles from the outlet of the transfer container.

[0012] Furthermore, in step 4, the light shielding rate of the laser particle size analyzer is set to 20%-40%.

[0013] As a preferred solution, in step 21, when the weight of the sieved soil sample is not higher than 100g, the amount of pure water used is 4000g; the aperture of the process pipeline and the return pipeline is not greater than 15mm; the amount of pure water introduced in step 23 is 1000g.

[0014] Beneficial effects: The present invention not only has the advantages of simple processing procedures and convenient operation, but also has high detection efficiency. The entire measurement process takes less than four hours. More importantly, it can accurately determine the soil particle size, and even acidic soil can be smoothly tested for particle size. The present invention achieves effective destruction of the bonding force between soil particles with an extremely simple scheme without using any chemical reagents, thereby ensuring the accuracy of the soil particle size measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the soil particle dispersion device in Example 1 Figure 1 ; Figure 2 Schematic diagram of the soil particle dispersion device in Example 1 Figure 2 ; Figure 3 It is a partial schematic diagram of the pipeline of the soil particle dispersion device in Example 1; Figure 4 It is a partial schematic diagram of the pipeline of the soil particle dispersion device in Example 2; Figure 5 This is a comparison chart of the soil particle size detection results in Example 1. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0017] Combination Figures 1 to 3 As shown, the soil particle dispersion device in this embodiment includes a feed container 1 and a transfer container 2, the outlet of the feed container 1 is connected to the inlet of the transfer container 2 through a process pipeline 3, and the outlet of the transfer container 2 is connected to the inlet of the transfer container 2 through a return pipeline 4, and a bidirectional booster pump 5 is provided on both the process pipeline 3 and the return pipeline 4. A plurality of fluid collision parts arranged at intervals are provided on the process pipeline 3 and the return pipeline 4, and each fluid collision part adopts a wear-resistant ball 9 arranged in the inner cavity of the pipeline. When the fluid in the pipeline flows, the fluid continues to flow after flushing the wear-resistant ball 9, wherein the aperture of the process pipeline 3 and the return pipeline 4 is 12mm, the process pipeline 3 and the return pipeline 4 are both made of stainless steel pipes, the wear-resistant ball 9 is made of a round ball made of NM400 material, the wear-resistant ball 9 is threadedly connected to the connecting rod 10, the connecting rod 10 is welded on the pipe wall of the pipeline, and the connecting rods 10 corresponding to adjacent wear-resistant balls 9 face opposite directions.

[0018] A soil particle size detection process, using the soil particle dispersion device in this embodiment, comprises the following steps: Step 1, pour the air-dried soil sample on a carrier, crush it with a wooden stick and sieve it, the sieve aperture is 2 mm, and a sieved soil sample is obtained; Step 2, placing the sieved soil sample into a soil particle dispersion device to physically disperse it into particles to obtain a wet soil particle sample; specifically: Step 21, after the sieved soil sample is loaded into the feed container 1, pure water is introduced into the feed container 1, and then the bidirectional booster pump 5 (forward operation) is controlled to run at the set pressure of 1 for 1.5 hours. The fluid pressure during this process is 0.3Mpa, and the flow direction of the fluid is as follows: Figure 1 As indicated by the middle arrow; when the weight of the sieved soil sample is no more than 100g, the amount of pure water used is 4000g; Step 22, control the bidirectional booster pump 5 (forward operation) to operate at set pressure 2 for 0.8 hours, and the fluid pressure during this process is 0.55 MPa; Step 23, only close the two-way booster pump 5 on the return pipeline 4, introduce all the fluid in the feed container 1 into the transfer container 2, then close the two-way booster pump 5 on the process pipeline 3, and then introduce pure water into the feed container 1 (the amount of pure water introduced in this step is 1000g, the purpose is to prevent soil particles from remaining in the feed container 1, the transfer container 2 and the pipeline), and then open the two-way booster pump 5 of the process pipeline 3 and the return pipeline 4 again (in this process, the two-way booster pump on the process pipeline 3 runs forward, and the two-way booster pump on the return pipeline 4 runs reversely, and the flow direction of the fluid is as follows Figure 2 The pure water in the feed container 1 is introduced into the transfer container 2, and finally the wet soil sample is collected from the outlet of the transfer container 2 (the solid-liquid mixture in the transfer container 2 is allowed to stand for a period of time, and most of the supernatant is removed first, and then the remaining solid-liquid mixture is collected in a measuring tool / beaker, and the remaining supernatant is removed after continuing to stand); Step 3, evaporating the water in the obtained wet soil particle sample to obtain a dry soil particle sample; Step 4, taking the obtained soil particle dry sample and adding it into the sample pool of the laser particle size analyzer, setting the laser particle size analyzer parameters, setting the light shielding rate of the laser particle size analyzer to 20%-40%, and then measuring the soil particle size in the sample.

[0019] This scheme omits the necessary operating steps of "adding H2O2 and defoaming agent, magnetic stirring, heating, adding sodium bisulfite solution for oscillation, adding HCl for stirring, adding alkali solution to adjust pH, and boiling on a magnetic stirrer" in the traditional scheme. It not only has the advantages of simple processing procedures and convenient operation, but also has high detection efficiency. The entire measurement process takes less than four hours. More importantly, it can accurately determine the soil particle size, and even acidic soil can be smoothly tested for particle size. This scheme is essentially different from the scheme in the existing standards. Without using any chemical reagents, it achieves effective destruction of the bonding force between soil particles with an extremely simple scheme, ensuring the accuracy of the soil particle size measurement results. This scheme uses a soil particle dispersion device to physically disperse the sieved soil sample into particles, making full use of the repeated collision and friction between the water flow containing soil and the wear-resistant sphere. This process is similar to the formation process of river sand, which is very convenient, so that the bonding force between soil particles can be smoothly and effectively destroyed. Example 2

[0020] A soil particle size detection process, referring to Example 1, which differs from Example 1 in that: Figure 4 As shown, each fluid collision part includes a pipe joint 6, a wear-resistant part 7 is arranged in the middle of the inner cavity of the pipe joint 6, and the wear-resistant part 7 is fixedly connected to the pipe joint 6 through a wear-resistant bracket. When the fluid in the pipeline flows, the fluid flushes the wear-resistant part 7 and then continues to flow. The wear-resistant part 7 adopts a spherical or nearly spherical diamond; In step 21, after the sieved soil sample is loaded into the feed container 1, pure water is introduced into the feed container 1, and then the two-way booster pump 5 (forward operation) is controlled to run at the set pressure one for 2 hours, and the fluid pressure in this process is 0.32Mpa; in step 22, the two-way booster pump 5 (forward operation) is controlled to run at the set pressure two for 1 hour, and the fluid pressure in this process is 0.6Mpa.

[0021] Yellow soil (acidic soil) from Jinyun Mountain, Chongqing was tested: According to the method in Example 1, 100 g of sieved soil sample was weighed and soil particles were dispersed. Finally, 100 g of dry soil sample was symmetrically taken in a manner of weighing 5 g of dry soil sample each time for soil particle size detection. The results are shown in Tables 1 and Figure 5 The results show that the clay, silt and sand content values ​​of the acidic yellow soil measured by the method of Example 1 have lower variability, and the standard deviation of the results measured by Example 1 is smaller than that by the pipette method. Table 1 Comparison of the content of sand, silt and clay particles measured by Example 1 and the straw method

Claims

1. A soil particle size detection process, characterized in that the steps include: Step 1, pour the air-dried soil sample on a carrier, crush it with a wooden stick and sieve it, the sieve aperture is 2 mm, and a sieved soil sample is obtained; Step 2, placing the sieved soil sample into a soil particle dispersion device to physically disperse it into particles to obtain a wet soil particle sample; Step 3, evaporating the water in the obtained wet soil particle sample to obtain a dry soil particle sample; Step 4, taking the obtained dry soil particle sample and adding it into the sample pool of the laser particle size analyzer, setting the parameters of the laser particle size analyzer, and measuring the soil particle size in the sample.

2. The soil particle size detection process according to claim 1, characterized in that: The soil particle dispersion device comprises a feed container (1) and a transfer container (2); the outlet of the feed container (1) is connected to the inlet of the transfer container (2) via a process pipeline (3); the outlet of the transfer container (2) is connected to the inlet of the transfer container (2) via a return pipeline (4); and both the process pipeline (3) and the return pipeline (4) are provided with a bidirectional booster pump (5).

3. The soil particle size detection process according to claim 2, characterized in that: A plurality of fluid impact parts are arranged at intervals on both the process pipeline (3) and the return pipeline (4), each fluid impact part comprising: a pipe joint (6), a wear-resistant part (7) is arranged in the middle of the inner cavity of the pipe joint (6), and the wear-resistant part (7) is fixedly connected to the pipe joint (6) through a wear-resistant bracket. When the fluid in the pipeline flows, the fluid flushes the wear-resistant part (7) and then continues to flow; or, each fluid impact part adopts a wear-resistant ball (9) arranged in the inner cavity of the pipeline.

4. The soil particle size detection process according to claim 3, characterized in that: The surface of the wear-resistant part (7) is a curved surface.

5. The soil particle size detection process according to any one of claims 1 to 4, characterized in that: The steps of starting the soil particle dispersion device to physically disperse the soil particles into particles are as follows: Step 21, after the sieved soil sample is loaded into the feed container (1), pure water is introduced into the feed container (1), and then the bidirectional booster pump (5) is controlled to operate at a set pressure of 1 for 1 to 2 hours, and the fluid pressure during this process is not higher than 0.32 MPa; Step 22, controlling the bidirectional booster pump (5) to operate at set pressure 2 for 0.5 to 1 hour, and the fluid pressure during this process is 0.5 to 0.6 MPa; Step 23, only close the bidirectional booster pump (5) on the return line (4), introduce all the fluid in the feed container (1) into the transfer container (2), then close the bidirectional booster pump (5) on the process line (3), and then introduce pure water into the feed container (1). Then, open the bidirectional booster pump (5) on the process line (3) and the return line (4) again, introduce all the pure water in the feed container (1) into the transfer container (2), and finally collect the wet sample of soil particles from the outlet of the transfer container (2).

6. The soil particle size detection process according to claim 5, characterized in that: In step 4, the shading rate of the laser particle size analyzer is set to 20%-40%.

7. The soil particle size detection process according to claim 6, characterized in that: In step 21, when the weight of the sieved soil sample is not higher than 100 g, the amount of pure water used is 4000 g; the apertures of the process pipeline (3) and the return pipeline (4) are not greater than 15 mm; and the amount of pure water introduced in step 23 is 1000 g.

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