Portable device and method for using γ ray to measure bulk density of soil sample obtained by means of cutting ring

Abstract

A portable device and method for using a γ ray to measure the bulk density of a soil sample obtained by means of a cutting ring, which belongs to the field of soil bulk density test devices. The device comprises a γ-ray source (1), a box body (2), a ray particle counter (11), a drawer-type sample box (8), and a power supply. The center of a ray detection window of the ray particle counter (11), the center of a third ray penetration hole (10) provided in a sample box top plate (9), the center of a second ray penetration hole (5) provided in a bottom plate of the drawer-type sample box (8), the center of a first ray penetration hole (4) provided in a sample box support plate (6), and the center of a γ ray exit hole (3) are on the same vertical line. γ ray intensities before and after the placement of a soil sample are recorded by means of the ray particle counter (11), and the bulk density of the soil sample is then directly calculated by means of a soil bulk density calculation formula.

Description

Portable device and method for detecting bulk density of ring-knife soil sample by gamma rays TECHNICAL FIELD

[0001] The present application belongs to the field of soil bulk density testing devices, and particularly relates to a portable device and method for detecting bulk density of ring-knife soil sample by gamma rays. BACKGROUND

[0002] In the method for measuring soil bulk density, it is generally divided into direct method and indirect method. The direct method can be further divided into constant volume method, non-constant volume method and instrument measurement method according to whether the area of the taken soil sample is fixed (Jiang Shengguo. Review of soil bulk density measurement methods in China. Hubei Agricultural Sciences, 2019, 58(S2): 82-86, 91.). The classical ring-knife method in the constant volume method is simple to operate, but time-consuming and laborious. Although the immersion method and the volume displacement method do not require a drying step, they have the disadvantages of low efficiency and high destructiveness (Chai Hua, He Nianpeng. Characteristics of soil bulk density in China and its significance for regional carbon storage estimation. Acta Ecologica Sinica, 2016, 36(13): 3903-3910. Ma Yuying, Lei Tingwu, Zhang Xiping, et al. Direct measurement of soil mass moisture content and soil bulk density by volume displacement method. Transactions of the Chinese Society of Agricultural Engineering, 2013, 29(09): 86-93.). The non-constant volume method is commonly used for measuring the bulk density of hard and fragile soil, which also requires a large amount of manpower and is highly destructive to the surface soil layer. The instrument measurement method can realize rapid measurement of soil bulk density in different scenes, but the instrument is expensive and some of them have nuclear radiation hazards. The soil moisture meter combined with the indirect method such as soil drill method has the advantages of accuracy and continuous measurement, but it is difficult to realize real-time measurement in field operation (Zhu Yantao, Qian Tianwei, Dun Dezhong. Measurement of soil bulk density by time domain reflectometer combined with soil drill method. Resources Development and Market, 2006(03): 213-215, 219.).

[0003] A Chinese invention patent with the authorization announcement number CN105738251B discloses a device and method for testing the bulk density of soil column profile by continuous scanning with gamma rays in the field. The patent designs two different ray sources for the detection of the bulk density of soil column samples, which can realize rapid detection of the bulk density of soil column samples. However, for the bulk density of soil samples collected by other methods, especially the soil samples collected by the ring-knife method, the above-mentioned patent cannot be used for detection.

[0004] Although there are currently many methods for detecting soil bulk density, due to the limitations of implementation conditions or strict requirements for test samples, these methods are difficult to be used for rapid measurement of the bulk density of ring-knife soil samples in the field environment. Therefore, it is urgent to design a device capable of rapid detection of the bulk density of ring-knife soil samples in the field. SUMMARY

[0005] The present application aims at solving the problems in the prior art and providing a portable device and method for detecting the bulk density of a ring-knife soil sample by using gamma rays.

[0006] The specific technical solutions adopted by the present application are as follows:

[0007] In the first aspect, the present application provides a portable device for detecting the bulk density of a ring-knife soil sample by using gamma rays, which comprises a gamma ray source, a box body, a ray particle counter, a drawer-type sample box and a power supply.

[0008] The box body is hollow, and the inside of the box body is sequentially provided from bottom to top with the gamma ray source, a sample box support plate, the drawer-type sample box for placing the soil sample, a sample box top plate and the ray particle counter; the bottom of the drawer-type sample box is provided with a sliding rail, and the drawer-type sample box and the sample box support plate are connected through the sliding rail; the inside of the drawer-type sample box is provided with a ring-knife box fixing ring for fixing the soil sample.

[0009] The top of the gamma ray source is provided with a gamma ray exit hole; the sample box support plate is provided with a first ray penetration hole, the bottom plate of the drawer-type sample box is provided with a second ray penetration hole, and the sample box top plate is provided with a third ray penetration hole; the center of the ray detection window of the ray particle counter is on the same vertical line as the centers of the third ray penetration hole, the second ray penetration hole, the first ray penetration hole and the gamma ray exit hole.

[0010] The power supply line of the power supply is connected with the gamma ray source and the ray particle counter respectively to realize power supply; the bottom of the box body is provided with universal casters through a caster support.

[0011] Preferably, the gamma ray source is a portable single-energy-level gamma ray source; the volume of the portable single-energy-level gamma ray source is equivalent to the volume of two standard 19-inch machine cases, and the size of each standard 19-inch machine case is 0.4826m x 0.0445m x 0.6m.

[0012] Preferably, the top of the box body is provided with a handle for easy taking.

[0013] Preferably, the front side of the drawer-type sample box is provided with a pull handle for easy pulling out.

[0014] Preferably, the power supply is a rechargeable lithium ion battery, and the power supply is provided with a switch.

[0015] Preferably, the caster support and the universal casters are both four, and are respectively arranged at the four corners of the bottom of the box body.

[0016] In the second aspect, the present application provides a method for detecting the bulk density of a ring-knife soil sample by using the portable device of the first aspect, and the specific steps are as follows:

[0017] S1: Pull out the drawer-type sample box, and cover both ends of the ring knife with the matching aluminum ring knife box cover and the bottom of the ring knife box respectively to obtain a complete ring knife box; then fix the ring knife box in the ring knife box fixing ring of the drawer-type sample box, ensuring that the center position of the bottom of the ring knife box is consistent with the center position of the second X-ray penetration hole on the bottom plate of the drawer-type sample box; push the drawer-type sample box back into the box body so that the bottom of the ring knife box, the center of the second X-ray penetration hole and the center of the first X-ray penetration hole are on the same vertical line;

[0018] S2: Turn on the power, the gamma-ray source emits gamma rays to operate, the gamma-ray particle counter starts counting, and the gamma-ray intensity I passing through the ring cutter box without soil sample is obtained. Al ;

[0019] S3: Cover both ends of the ring cutter containing the soil sample with the aluminum ring cutter box cover and the bottom of the ring cutter box respectively, and then fix it in the ring cutter box fixing ring of the drawer-type sample box. Repeat steps S1 and S2 to obtain the gamma ray intensity I passing through the ring cutter box containing the soil sample.

[0020] S4: Transfer the I obtained in step S2 Al Substitute the I obtained in step S3 into the soil bulk density calculation formula to obtain the bulk density of the soil sample.

[0021] Preferably, the soil bulk density calculation formula is as follows:

[0022] In the formula: I0 is the initial gamma-ray intensity emitted by the γ-ray source, in Bq; I Al I is the gamma-ray intensity passing through the ring cutter box without soil samples, in Bq; I is the gamma-ray intensity passing through the ring cutter box containing soil samples, in Bq; μ Al The gamma-ray mass attenuation coefficient for metallic aluminum is given in cm⁻¹. 2 / g;ρ Al This is the density of metallic aluminum, expressed in g / cm³. 3 L Al ρ is the height of the entire cutter box, in cm. w This is the density of water, expressed in g / cm³. 3 L represents the height of the soil sample inside the ring sampler box, in cm; μ s The gamma-ray mass attenuation coefficient of the soil is expressed in cm. 2 / g.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] The device provided by the application adopts a single energy level portable gamma ray source, can directly irradiate a cutting ring method soil sample, and quickly measures the bulk density of the soil sample through a soil bulk density calculation formula. Compared with the traditional cutting ring sampling and drying method, the portable device provided by the application can directly test the bulk density of the soil sample in the field, and is more suitable for large-scale or on-site rapid analysis. BRIEF DESCRIPTION OF DRAWINGS

[0025] Fig. 1 is a schematic diagram of the portable device provided by the embodiment;

[0026] Fig. 2 is a longitudinal sectional view of the portable device provided by the embodiment;

[0027] Fig. 3 is a schematic diagram of the drawer type sample box provided by the embodiment;

[0028] Fig. 4 is a schematic diagram of the bottom of the drawer type sample box provided by the embodiment;

[0029] Fig. 5 is a precision test diagram of the test results of the bulk density of the soil sample provided by the embodiment;

[0030] In the figure: gamma ray source 1, box 2, gamma ray exit hole 3, first ray penetration hole 4, second ray penetration hole 5, sample box support plate 6, handle 7, drawer type sample box 8, sample box top plate 9, third ray penetration hole 10, ray particle counter 11, handle 12, caster bracket 13, universal caster 14, cutting ring box fixing ring 801, sliding rail 802. DETAILED DESCRIPTION

[0031] The application will be further described and explained in conjunction with the accompanying drawings and specific embodiments. The technical features of each embodiment in the application can be combined accordingly without conflict.

[0032] In the description of the application, it should be understood that the terms "first" and "second" are only used for distinguishing purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features.

[0033] As a preferred embodiment of the application, the embodiment provides a portable device for detecting the bulk density of a cutting ring soil sample by using gamma rays. As shown in Figs. 1 and 2, the device includes a gamma ray source 1, a box 2, a ray particle counter 11, a drawer type sample box 8, and a power supply.

[0034] In this embodiment, the radiation particle counter is a detection device for recording gamma ray intensity and energy. In order to improve the portability of the detection ring knife soil sample bulk density device, a portable single-energy gamma ray source is used in this embodiment. The size of a standard 19-inch case is specifically: the length is 19 inches, that is, 0.4826 m, the height is 0.0445 m, and the depth is 0.6 m. The volume of the portable single-energy gamma ray source is equivalent to the volume of two standard 19-inch cases stacked. Those skilled in the art can select a single-energy gamma ray source of appropriate size according to actual needs, so that the overall device meets the conditions of field detection.

[0035] In the device provided by the embodiment, the box body 2 is a hollow structure, and the inside of the box body 2 is sequentially provided from bottom to top with the gamma ray source 1, the sample box support plate 6, the drawer-type sample box 8, the sample box top plate 9, and the radiation particle counter 11. The inside of the drawer-type sample box 8 is used to place soil samples.

[0036] As shown in FIG. 3, the inside of the drawer-type sample box 8 is provided with a cutting ring box fixing ring 801 for fixing soil samples. The cutting ring box fixing ring 801 is fixed on the bottom plate of the drawer-type sample box 8. The bottom plate of the drawer-type sample box 8 is also provided with a second radiation penetration hole 5.

[0037] As shown in FIG. 4, the bottom of the drawer-type sample box 8 is provided with a sliding rail 32, which is in sliding connection with the sample box support plate 6, so that the drawer-type sample box 8 can be pulled out like a drawer.

[0038] In the device provided by the embodiment, the top of the gamma ray source 1 is a gamma ray exit hole 3, the sample box support plate 6 is provided with a first radiation penetration hole 4, the bottom plate of the drawer-type sample box 8 is provided with a second radiation penetration hole 5, and the sample box top plate 9 is provided with a third radiation penetration hole 10. The center of the radiation detection window of the radiation particle counter 11 is on the same vertical line as the centers of the third radiation penetration hole 10, the second radiation penetration hole 5, the first radiation penetration hole 4, and the gamma ray exit hole 3, so that the radiation particle counter 11 can record the gamma ray intensity emitted by the gamma ray source 1 under different conditions.

[0039] In the device provided by the embodiment, the power supply line of the power supply is connected with the gamma ray source 1 and the radiation particle counter 11 respectively to realize power supply. In this embodiment, the power supply is a rechargeable lithium ion battery, and the power supply is provided with a switch. Those skilled in the art can also select other portable power supplies according to actual conditions.

[0040] In order to realize the portability of the device, the bottom of the box body 2 is fixed with four caster supports 13 respectively, and each caster support 13 is provided with one universal caster 14, so that the device can be conveniently moved. The top of the box body 2 is provided with a handle 12 for easy taking, and the front side of the drawer type sample box 8 is also provided with a pull handle 7 for easy extraction.

[0041] The device provided by the application is suitable for rapid detection of the bulk density of a soil sample collected by a cutting ring method in the field. The cutting ring method usually adopts a stainless steel cutting ring, which is a hollow cylindrical barrel and is provided with a special aluminum cutting ring cover and a cutting ring bottom.

[0042] The embodiment also provides a method for detecting the bulk density of a cutting ring soil sample by using the portable device, and the specific steps are as follows:

[0043] S1: pull out the drawer type sample box 8, cover the two ends of the cutting ring with the matching aluminum cutting ring cover and cutting ring bottom respectively, and obtain a complete cutting ring box, wherein the cutting ring box is not loaded with a collected soil sample.

[0044] Then, the cutting ring box is fixed in the cutting ring box fixing ring 801 of the drawer type sample box 8, so as to ensure that the center position of the cutting ring box bottom is consistent with the center position of the second ray penetration hole 5 on the bottom plate of the drawer type sample box 8; and the drawer type sample box 8 is pushed back to the box body 2, so that the centers of the cutting ring box bottom, the second ray penetration hole 5 and the first ray penetration hole 4 are on the same vertical line.

[0045] S2: turn on the power supply, the gamma ray source 1 emits gamma rays to work, and the ray particle counter 11 starts counting to obtain the gamma ray intensity I0 passing through the cutting ring box without loading the soil sample. Al ;

[0046] S3: cover the two ends of the cutting ring loaded with the soil sample with the above-mentioned aluminum cutting ring cover and cutting ring bottom respectively, and then fix them in the cutting ring box fixing ring 801 of the drawer type sample box 8. Referring to steps S1 and S2, the center position of the cutting ring box bottom is consistent with the center position of the second ray penetration hole 5 on the bottom plate of the drawer type sample box 8; and the drawer type sample box 8 is pushed back to the box body 2, so that the centers of the cutting ring box bottom, the second ray penetration hole 5 and the first ray penetration hole 4 are on the same vertical line. Turn on the power supply, the gamma ray source 1 emits gamma rays to work, and the ray particle counter 11 starts counting to obtain the gamma ray intensity I passing through the cutting ring box loaded with the soil sample.

[0047] S4: substitute I0 obtained in step S2 and I obtained in step S3 into the soil bulk density calculation formula: Al

[0048] In the formula, I0 is the initial gamma ray intensity emitted by the gamma ray source, and the unit is Bq; I is the gamma ray intensity passing through the cutting ring box loaded with the soil sample.​Al I is the gamma-ray intensity passing through the ring cutter box without soil samples, in Bq; I is the gamma-ray intensity passing through the ring cutter box containing soil samples, in Bq; μ Al The gamma-ray mass attenuation coefficient of metallic aluminum is given in cm. 2 / g;ρ Al This is the density of metallic aluminum, expressed in g / cm³. 3 L Al ρ is the height of the entire cutter box, in cm. w This is the density of water, expressed in g / cm³. 3 L represents the height of the soil sample inside the ring sampler box, in cm; μ s The gamma-ray mass attenuation coefficient of the soil, in cm. 2 / g.

[0049] It should be noted that, for the aluminum ring cutter box cover and ring cutter box bottom, A is a constant. A can be used... Calculations can also be performed using μ. Al ρ Al L Al Calculation. When selected During calculation, parameters I0 and I Al All can be obtained using a ray particle counter. When A = μ is chosen... Al ρ Al L Al During calculation, μ Al and ρ Al All of these can be obtained by consulting relevant materials. Al This refers to the height of the entire ring cutter box. Those skilled in the art can choose a suitable calculation method based on the convenience of the calculation.

[0050] μ Al The gamma-ray mass attenuation coefficient of metallic aluminum varies at different gamma-ray energy levels. Therefore, for ease of calculation in this embodiment, we choose... Calculation. Only I0 and I need to be read during the experiment. Al That's all.

[0051] The bulk density of a batch of soil samples collected in the field in Nyingchi, Tibet, was determined using the method described above. To verify the accuracy of the apparatus and method provided in this invention in obtaining soil bulk density, the coefficient of determination (R²) was used. 2 The root mean square error (RMSE) and the ratio of the standard deviation of the measured value to the standard prediction error (RPD) are used as evaluation parameters, and their specific calculations are shown in the formulas: RPD = SD / RMSE

[0052] In the formula: Y iThe bulk density data of the soil sample measured by the method of the present application, The bulk density data of the same soil sample measured by the traditional analysis method, The average value of Y i The average value of Y The average value of Y The standard deviation of Y i The sample number.

[0053] The results of the accuracy test are shown in Figure 5, and the results are: R 2 = 0.9466, RMSE = 0.0575, and RPD = 4.3124. R 2 , RMSE and RPD data and the effect of the figure show that the soil bulk density data of the soil sample measured by the device and method of the present application has good accuracy; at the same time, the bulk density data of a soil sample measured by the method takes less than 5 minutes, and the detection speed is faster than the traditional drying method, which has a prominent and significant technical effect.

[0054] The above-described embodiments are only a preferred scheme of the present application, and are not intended to limit the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, any technical scheme obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present application.

Claims

1. A portable device for detecting the bulk density of a ring-shaped soil sample using gamma rays, characterized in that, Includes a gamma-ray source (1), a housing (2), a gamma-ray particle counter (11), a drawer-type sample box (8), and a power supply; The box (2) has a hollow structure. Inside the box (2), from bottom to top, are arranged a gamma-ray source (1), a sample box support plate (6), a drawer-type sample box (8) for placing soil samples, a sample box top plate (9), and a gamma-ray particle counter (11). The bottom of the drawer-type sample box (8) is provided with a slide rail (32), which is slidably connected to the sample box support plate (6). Inside the drawer-type sample box (8), there is a ring holder fixing ring (801) for fixing the soil samples. The top of the gamma-ray source (1) is a gamma-ray emission hole (3); a first ray penetration hole (4) is opened on the sample box support plate (6), a second ray penetration hole (5) is opened on the bottom plate of the drawer-type sample box (8), and a third ray penetration hole (10) is opened on the top plate (9) of the sample box; the center of the ray detection window of the ray particle counter (11) is on the same vertical line as the center of the third ray penetration hole (10), the second ray penetration hole (5), the first ray penetration hole (4) and the gamma-ray emission hole (3); The power supply line of the power source is connected to the γ-ray source (1) and the ray particle counter (11) respectively to realize power supply; the bottom of the box (2) is equipped with universal casters (14) through caster bracket (13).

2. The portable device for detecting the bulk density of a ring cutter soil sample using gamma rays according to claim 1, characterized in that, The gamma-ray source (1) is a portable single-level gamma-ray source.

3. The portable device for detecting the bulk density of a ring cutter soil sample using gamma rays according to claim 1, characterized in that, The top of the box (2) is provided with a handle (12) for easy handling.

4. The portable device for detecting the bulk density of a ring-shaped soil sample using gamma rays according to claim 1, characterized in that, The front of the drawer-type sample box (8) is provided with a handle (7) for easy extraction.

5. The portable device for detecting the bulk density of a ring cutter soil sample using gamma rays according to claim 1, characterized in that, The power supply uses a rechargeable lithium-ion battery and is equipped with a switch.

6. The portable device for detecting the bulk density of a ring cutter soil sample using gamma rays according to claim 1, characterized in that, The caster bracket (13) and swivel casters (14) are all in sets of four, which are respectively set at the four corners of the bottom of the box (2).

7. A method for detecting the bulk density of a ring cutter soil sample using the portable device described in any one of claims 1 to 6, characterized in that, The specific steps are as follows: S1: Pull out the drawer-type sample box (8), and cover the two ends of the ring knife with the matching aluminum ring knife box lid and the ring knife box bottom respectively to obtain a complete ring knife box; The ring knife box is then fixed in the ring knife box fixing ring (801) of the drawer-type sample box (8) to ensure that the center position of the bottom of the ring knife box is consistent with the center position of the second X-ray penetration hole (5) on the bottom plate of the drawer-type sample box (8); Push the drawer-type sample box (8) back into the box body (2) so that the bottom of the ring knife box, the center of the second X-ray penetration hole (5) and the first X-ray penetration hole (4) are on the same vertical line; S2: Turn on the power, the γ-ray source (1) emits γ-rays to operate, the γ-ray particle counter (11) starts counting, and obtains the gamma-ray intensity I passing through the ring cutter box without soil sample. Al ; S3: Cover the two ends of the ring cutter containing the soil sample with the aluminum ring cutter box cover and the bottom of the ring cutter box respectively, and then fix it in the ring cutter box fixing ring (801) of the drawer-type sample box (8). Repeat steps S1 and S2 to obtain the gamma ray intensity I passing through the ring cutter box containing the soil sample. S4: Transfer the I obtained in step S2 Al Substitute the I obtained in step S3 into the soil bulk density calculation formula to obtain the bulk density of the soil sample.

8. The method for detecting the bulk density of a ring sampler soil sample according to claim 7, characterized in that, The formula for calculating soil bulk density is as follows: In the formula: I0 is the initial gamma-ray intensity emitted by the γ-ray source, in Bq; I Al I is the gamma-ray intensity passing through the ring cutter box without soil samples, in Bq; I is the gamma-ray intensity passing through the ring cutter box containing soil samples, in Bq; μ Al The gamma-ray mass attenuation coefficient of metallic aluminum is given in cm. 2 / g;ρ Al This is the density of metallic aluminum, expressed in g / cm³. 3 L Al ρ is the height of the entire cutter box, in cm. w This is the density of water, expressed in g / cm³. 3 L represents the height of the soil sample inside the ring sampler box, in cm; μ s The gamma-ray mass attenuation coefficient of the soil, in cm. 2 / g.

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