Multi-point detection method for content of heavy metals in soil

Abstract

The invention relates to a multi-point detection method for the content of heavy metals in soil, which is applied to the related technical field of soil detection, by arranging a plurality of detection piles, multi-point and different-depth synchronous initial detection of to-be-detected soil can be realized firstly, and then the detection precision is effectively ensured in cooperation with a laboratory rechecking mode, so that the detection accuracy is improved. In addition, in the process, in cooperation with sample pre-filling operation, before the detection pile is pre-embedded, a sample can be put into the pre-assimilation strip at the target depth in advance, so that the sample is gradually assimilated with surrounding soil in the pre-embedding detection process, and when re-detection is conducted after the initial detection is abnormal, the pre-assimilation strip at the target depth can be put into the pre-assimilation strip at the target depth. According to the method, the pre-assimilation strip can be directly taken out to obtain the sample at the abnormal point position, and compared with the prior art, excavation sampling is not needed, the excavation sampling process can be effectively simplified, the detection time span is greatly shortened, and the detection efficiency is improved.

Description

Technical Field

[0001] The present invention relates to a multi-point detection method for heavy metal content in soil, and in particular to a multi-point detection method for heavy metal content in soil applied in the technical field related to soil detection. Background Art

[0002] In the prior art, the detection of heavy metal contamination in soil generally involves in-situ detection and sampling for laboratory testing. The sampling detection method has low overall timeliness due to the need for excavation of the soil and transportation of samples to the laboratory. For example, Chinese Patent Specification No. CN118776969B discloses a sampling method for detecting heavy metal-contaminated soil. In-situ detection is generally performed using pre-buried sensors. For example, Chinese Patent Specification No. CN212722714U discloses a sensor for in-situ online monitoring and adsorption of heavy metal pollution in a wetland environment. However, this method has lower detection accuracy than laboratory testing, which makes it easy to misjudge the heavy metal content in the soil, hindering the timely remediation of contaminated soil.

[0003] To solve the above problems, a comprehensive testing method is often used, which includes pre-buried initial inspection and sampling for re-inspection in the laboratory. However, after the pre-buried initial inspection, it is necessary to excavate again and then take targeted samples at the inspection points. That is, the entire process requires two excavations before testing can be carried out. This process is cumbersome, resulting in a long span of the entire inspection and low inspection efficiency. Summary of the Invention

[0004] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is that after the initial pre-buried inspection, the process of excavation and sampling for re-inspection is cumbersome and has low inspection efficiency.

[0005] To solve the above problems, the present invention provides a multi-point detection method for heavy metal content in soil, comprising the following steps: S1. First, excavate multiple points in the soil where heavy metal contamination may exist, and pre-bury multiple detection piles. At the same time, multiple detection piles are marked. Before pre-burying, the detection piles are pre-filled with samples. The minimum interval between two adjacent detection piles is 1 meter. Multiple detection piles are connected to the external detection terminal signal; S21. After pre-embedding, let it stand for 48 hours until the soil structure gradually recovers and stabilizes. Then, remotely activate the detection function of the detection pile to detect the soil and conduct preliminary detection of heavy metal content at multiple depths and points in real time. S22. When the detection terminal receives the data of the heavy metal content exceeding the standard in the initial detection, it locates the detection pile at the abnormal point according to the data source and takes out the sample pre-filled in the target depth; S3. Conduct targeted re-examination and testing of the sample in the laboratory using a mass spectrometer. If the test results show that the heavy metal content exceeds the standard, targeted treatment will be carried out; The detection pile includes a positioning cone, a plurality of detection sections that are threadedly connected in sequence, and an extension tube that is threadedly connected to the top of the uppermost detection section. The top cover of the extension tube is provided with a top sealing cover. The lowermost detection section is threadedly fixed to the positioning cone. The detection section includes an embedded tube, an outer sheath fixedly sleeved on the outer end of the embedded tube, and a threaded ring fixedly connected to the lower end of the embedded tube and the outer sheath. The outer ends of the embedded tube and the outer sheath are fixedly penetrated with a lofting tube. A heavy metal monitoring unit is fixedly installed on the inner wall of the embedded tube near the lower edge. The heavy metal monitoring unit includes a screw threaded on the inner end of the embedded tube. A bottom plate fixedly connected to the wall, a heavy metal ion sensor installed on the upper end of the bottom plate, the detection end of the heavy metal ion sensor movably penetrates the embedded tube and extends outside the embedded tube, a pre-assimilation strip is movably inserted into the middle of the lofting tube toward the embedded tube, the upper end of the bottom plate is also fixedly connected to a back plate, an electromagnetic sheet is fixedly connected to the middle of the back plate, the middle of the electromagnetic sheet is facing the pre-assimilation strip, one end of the pre-assimilation strip close to the back plate is located outside the lofting tube and is tied with a sampling rope, the upper end of the sampling rope sequentially penetrates the multiple embedded tubes and the extension tube above and is fixedly connected to the top of the top cover; The sample pre-filling process in step S1 is as follows: First, the pre-assimilation sample is filled in the pre-assimilation bar, and the quicksand medium is filled in the sampling tube, and the pre-assimilation bar is buried in the quicksand medium. The quicksand medium includes 93%-97% silica sand and 3%-7% bentonite by mass.

[0006] In the above-mentioned multi-point detection method for heavy metal content in soil, by setting up multiple detection piles, simultaneous detection at multiple points and different depths can be achieved. Combined with the sample pre-filling operation, when it is initially detected that the heavy metal content exceeds the standard, the pre-assimilated sample placed in advance can be directly taken out and re-inspected. Compared with the existing technology, it can effectively simplify the excavation and sampling process, thereby greatly shortening the detection time span and improving detection efficiency.

[0007] As a further improvement of the present application, when pre-buried, the top of each detection pile is higher than the soil surface, and different marking labels are attached to the exposed parts.

[0008] As a further improvement of the present application, the end of the lofting tube facing the embedded tube is a flat surface, the end of the lofting tube facing the outside of the detection section is a cylinder, and the outer end of the cylinder is drilled with multiple evenly distributed through holes.

[0009] As a further improvement of the present application, the pre-assimilation strip includes an edge magnetic plate movably inserted on the flat surface of the sample tube, a positioning plate movably inserted on the cylindrical surface of the sample tube, and a plurality of restraining strips fixedly connected between the edge magnetic plate and the positioning plate. The plurality of restraining strips are distributed in a circular array, and a limiting groove is opened at the outer end of the edge magnetic plate. The connection point between the sample collection rope and the pre-assimilation strip is located in the limiting groove, and the sample is filled in the space surrounded by the edge magnetic plate, the restraining strip and the positioning plate.

[0010] As another improvement of the present application, the pre-assimilation sample is the soil of the depth corresponding to the sampling tube obtained during the pre-buried excavation. A soil-carrying rod is movable through the middle of the side magnetic plate and the positioning plate. The soil-carrying rod includes a pull rod and a circular magnetic piece and a soil-pressing piece fixedly connected to the left and right ends of the pull rod respectively. A depression is excavated in the middle of the side magnetic plate. The circular magnetic piece is in contact with the vertical inner wall of the groove. The soil-pressing piece is located on the outside of the pre-assimilation strip, and the soil-pressing piece is an arc-shaped piece arched toward the side away from the positioning plate. When the back plate is energized, it generates magnetic attraction to the circular magnetic piece and the side magnetic plate at the same time.

[0011] As another improved supplement to the present application, the restraining strip is an arc-shaped strip that arches outward toward the edge magnetic plate, and a plurality of restraining ropes are fixedly connected between the pull rod and the plurality of restraining strips. The plurality of restraining strips are made of elastic metal sheet material, and the distance between the middle of the outer surface of the restraining strip and the axis of the edge magnetic plate is not greater than the radius of the edge magnetic plate. The pull rod is made of corrosion-resistant non-elastic material.

[0012] As another improvement of the present application, the pre-assimilated sample is an aggregation capsule, which is located between multiple binding strips. A T-shaped groove is opened in the middle of the edge magnetic plate. The T-shaped groove is coaxial with the aggregation capsule. The aggregation capsule includes two positioning hemispheres, an outer adsorption layer fixedly connected between the two positioning hemispheres, and an inner control capsule. The inner control capsule is located in the outer adsorption layer and is filled with compressed air. A rubber plug is provided at the end of the inner control capsule close to the edge magnetic plate. The rubber plug movably passes through the corresponding edge magnetic plate and extends into the T-shaped slot.

[0013] As another improved supplement to the present application, the electromagnetic sheet includes an outer magnetic ring and an inner magnetic sheet. The inner magnetic sheet is located on the inner side of the outer magnetic ring, and the two are coaxially arranged. A magnetic shielding layer is also arranged between the outer magnetic ring and the inner magnetic sheet. A pull rope is also fixedly connected between the rubber plug and the inner magnetic sheet. The outer magnetic ring and the inner magnetic sheet correspond to the edge magnetic plate and the rubber plug respectively.

[0014] In summary, by setting up multiple detection piles, it is possible to first realize simultaneous initial detection of multiple points and different depths of the soil to be tested, and then cooperate with the laboratory review method to effectively ensure the detection accuracy and make the detection effect of heavy metal content more accurate. In addition, in this process, in conjunction with the sample pre-filling operation, before the detection pile is pre-buried, the sample can be placed in the pre-assimilation strip at the target depth in advance, so that it can gradually assimilate with the surrounding soil during the pre-buried detection process. When the initial inspection is abnormal and the re-inspection is carried out, the pre-assimilation strip can be directly taken out to obtain the sample at the abnormal point. Compared with the existing technology, there is no need for excavation and sampling, which can effectively simplify the excavation and sampling process. That is, the existing technology requires excavation once for pre-buried and excavation again for sampling, while the present application does not require secondary excavation when sampling, thereby reducing the tediousness of sampling, thereby greatly shortening the time span of detection and improving detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the main flow chart of the first embodiment of this application; Figure 2 This is a schematic diagram of the arrangement of detection piles in the first embodiment of the present application; Figure 3 A perspective view of a detection pile according to a first embodiment of the present application; Figure 4 This is an exploded view of the detection pile according to the first embodiment of the present application; Figure 5 This is a three-dimensional diagram of the detection section of the first embodiment of the present application; Figure 6 A cross-sectional view of the detection section according to the first embodiment of the present application; Figure 7 This is a three-dimensional diagram of a heavy metal monitoring unit according to a first embodiment of the present application; Figure 8 This is an exploded view of the lofting tube according to the first embodiment of the present application; Figure 9 This is a cross-sectional view of the top cover according to the first embodiment of the present application; Figure 10 A perspective view of the pre-assimilation strip portion of the first embodiment of the present application; Figure 11 This is a cross-sectional view of the pre-assimilation strip portion of the first embodiment of the present application; Figure 12 This is a schematic diagram of the first embodiment of the present application when the pre-assimilation strip is forced to gradually separate from the lofting tube; Figure 13 This is a cross-sectional view of the pre-assimilation strip portion of the second embodiment of the present application; Figure 14 This is a schematic diagram of the changes of the pre-assimilation strip after being subjected to magnetic attraction in the second embodiment of the present application; Figure 15 This is a schematic diagram of the third embodiment of the present application when the pre-assimilation strip is filled with aggregation capsules; Figure 16 Schematic diagram of the third embodiment of the present application when the aggregated capsule absorbs water to enrich heavy metal ions Figure 17 This is a front view of the magnetron plate in the third embodiment of the present application.

[0016] Description of the numbers in the figure: 1 detection section, 11 embedded tube, 12 outer sheath, 13 threaded ring, 2 positioning cone, 3 extension tube, 4 top cover, 5 lofting tube, 501 through hole, 6 heavy metal monitoring unit, 61 heavy metal ion sensor, 62 bottom plate, 63 back plate, 631 outer magnetic ring, 632 inner magnetic sheet, 7 pre-assimilation strip, 71 side magnetic plate, 72 restraining strip, 73 positioning plate, 741 circular magnetic sheet, 742 pull rod, 743 soil pressing sheet, 744 restraining rope, 8 sampling rope, 91 outer adsorption layer, 92 positioning hemisphere, 93 inner control capsule, 941 rubber plug, 942 pull rope. DETAILED DESCRIPTION

[0017] The following describes three implementation methods of the present application in detail with reference to the accompanying drawings.

[0018] The first implementation method: Figure 1-2 A multi-point detection method for heavy metal content in soil is shown, comprising the following steps: S1. First, excavate multiple points in the soil where heavy metal contamination may exist, and pre-bury multiple detection piles. At the same time, multiple detection piles are marked. Before pre-burying, the detection piles are pre-filled with samples. The minimum interval between two adjacent detection piles is 1 meter. Multiple detection piles are connected to the external detection terminal signal; The sample pre-filling process in step S1 is as follows: First, the pre-assimilation sample is filled into the pre-assimilation strip 7. The pre-assimilation sample is the soil obtained during the pre-buried excavation at a depth corresponding to the lofting tube 5. The lofting tube 5 is then filled with a quicksand medium, and the pre-assimilation strip 7 is buried in the quicksand medium. The quicksand medium consists of 93%-97% silica sand and 3%-7% bentonite by mass. The permeability coefficient is maintained within the range of (1.2±0.3)×10⁻³ cm / s and the Martens viscosity is ≤35 mPa·s, as tested according to ASTM D7263. This ratio maintains high permeability while forming a stable pore structure through the hydration expansion of the bentonite (expansion index ≥10 mL / 2g), ensuring the effective migration of heavy metal ions with groundwater. When it is pre-buried underground, heavy metal ions will penetrate into the soil along with underground water. When the heavy metal ion content is high, the water will enter the sample tube 5 along the through hole 501 and penetrate into the pre-assimilation strip 7 along the highly permeable quicksand medium, so that the pre-assimilation sample can quickly penetrate water containing heavy metal ions, making it gradually consistent with the heavy metal ion content of the surrounding soil. The corresponding pre-assimilation strip 7 can be directly taken out later, and then re-inspected in the experiment. Compared with the detection method of excavating and sampling after the initial inspection, it effectively reduces the tediousness of the operation and can also effectively save time. After the initial inspection is abnormal, it can be quickly re-inspected to improve the detection efficiency and timeliness.

[0019] S21. After pre-embedding, let it stand for 48 hours until the soil structure gradually recovers and stabilizes. Then, remotely activate the detection function of the detection pile to detect the soil and conduct preliminary detection of heavy metal content at multiple depths and points in real time. S22. When the detection terminal receives the data of the heavy metal content exceeding the standard in the initial detection, it locates the detection pile at the abnormal point according to the data source and takes out the sample pre-filled in the target depth; S3. The samples are subjected to targeted re-examination and testing in the laboratory through a mass spectrometer. When the test results show that the heavy metal content exceeds the standard, targeted treatment is carried out. By setting up multiple detection piles, simultaneous detection at multiple points and different depths can be achieved. In conjunction with the sample pre-filling operation, when it is initially detected that the heavy metal content exceeds the standard, the pre-assimilated sample placed in advance can be directly taken out and re-tested. Compared with the existing technology, it can effectively simplify the excavation and sampling process, thereby greatly shortening the detection time span and improving detection efficiency.

[0020] Figure 3-4 As shown, the detection pile includes a positioning cone 2, a plurality of detection sections 1 that are threadedly connected in sequence, and an extension tube 3 that is threadedly connected to the top of the top detection section 1. The top cover of the extension tube 3 is provided with a top cover 4. The bottom detection section 1 is threadedly fixed to the positioning cone 2. Figure 5 The detection section 1 includes an embedded tube 11, an outer protective layer 12 fixedly sleeved on the outer end of the embedded tube 11, and a threaded ring 13 fixedly connected to the lower ends of the embedded tube 11 and the outer protective layer 12. The outer ends of the embedded tube 11 and the outer protective layer 12 are fixedly penetrated by a lofting tube 5. A heavy metal monitoring unit is fixedly installed on the inner wall of the embedded tube 11 near the lower edge. The end of the lofting tube 5 facing the inside of the embedded tube 11 is a flat surface, and the end of the lofting tube 5 facing the outside of the detection section 1 is a cylinder, and a plurality of evenly distributed through holes 501 are drilled on the outer end of the cylinder. The through holes 501 make the lofting tube 5 transparent inside and outside, so that the pre-assimilation strip 7 inside it can be assimilated with the external soil.

[0021] like Figure 6-7The heavy metal monitoring unit includes a base plate 62 fixedly connected to the inner wall of the embedded tube 11 and a heavy metal ion sensor 61 installed on the upper end of the base plate 62. The detection end of the heavy metal ion sensor 61 is movable through the embedded tube 11 and extends outside the embedded tube 11. After embedding, the detection end of the heavy metal ion sensor 61 is in direct contact with the soil, and can directly and preliminarily detect the heavy metal content in the soil.

[0022] like Figure 8-9 The sampling tube 5 is movably inserted with a pre-assimilation strip 7 in the middle of the embedded tube 11, and the upper end of the bottom plate 62 is also fixedly connected to a back plate 63, and an electromagnetic sheet is fixedly connected to the middle of the back plate 63. The middle of the electromagnetic sheet is facing the pre-assimilation strip 7. The end of the pre-assimilation strip 7 close to the back plate 63 is located outside the sampling tube 5 and is fastened with a sampling rope 8. The upper end of the sampling rope 8 passes through the multiple embedded tubes 11 and the extension tube 3 above in sequence and is fixedly connected to the top of the top cover 4. When the heavy metal ion content is too high during the initial inspection, the abnormal detection pile can be directly located according to the data source, and then the corresponding top cover 4 is unscrewed, and then the electromagnetic sheet on the corresponding back plate 63 is controlled to be energized to adsorb the pre-assimilation strip 7, so that the pre-assimilation strip 7 is separated from the sampling tube 5, and then the pre-assimilation strip 7 is pulled out by the corresponding sampling rope 8 to complete the sampling. Compared with excavation sampling, the labor complexity is effectively reduced.

[0023] It is worth noting that the multiple sampling ropes 8 corresponding to different pre-assimilation strips 7 have different colors, and the depth of the abnormal point can be judged according to the data source, so that the pre-assimilation strip 7 at the corresponding depth can be taken out to make the re-inspection result more accurate.

[0024] During pre-embedding, the top of each detection pile is higher than the soil surface, and different marking labels are attached to the exposed part to facilitate the removal of the corresponding pre-assimilation strip 7 during re-inspection.

[0025] like Figure 10-11 The pre-assimilation strip 7 includes a side magnetic plate 71 movably inserted on the flat surface of the sample tube 5, a positioning plate 73 movably inserted on the cylindrical surface of the sample tube 5, and a plurality of restraint strips 72 fixedly connected between the side magnetic plate 71 and the positioning plate 73. The plurality of restraint strips 72 are distributed in a circular array. A limiting groove is drilled at the outer end of the side magnetic plate 71. The connection between the sample collection rope 8 and the pre-assimilation strip 7 is located in the limiting groove. The sample is filled in the space surrounded by the side magnetic plate 71, the restraint strip 72 and the positioning plate 73.

[0026] like Figure 11In the figure, c represents the pre-assimilation sample, b represents the soil around the detection pile, and a soil rod is movable through the middle of the side magnetic plate 71 and the positioning plate 73. The soil rod includes a pull rod 742 and a circular magnetic piece 741 and a soil pressing piece 743 fixedly connected to the left and right ends of the pull rod 742. A recess is excavated in the middle of the side magnetic plate 71, and the circular magnetic piece 741 is in contact with the vertical inner wall of the recess. The soil pressing piece 743 is located on the outside of the pre-assimilation strip 7, and the soil pressing piece 743 is facing the side away from the positioning plate 73. The back plate 63 is energized and generates magnetic attraction to the circular magnetic piece 741 and the side magnetic plate 71 at the same time. When the pre-assimilation strip 7 needs to be taken out, the electromagnetic piece is energized and generates magnetic attraction to the side magnetic plate 71 and the circular magnetic piece 741 at the same time. At this time, the circular magnetic piece 741 is displaced relative to the detection node 1, thereby moving the soil pressing piece 743 toward the positioning plate 73, thereby clamping part of the soil between the soil pressing piece 743 and the positioning plate 73. Since the soil pressing piece 743 is arc-shaped, Figure 12 , so that after the subsequent pre-assimilation strip 7 is taken out, the pre-assimilated samples in the multiple restraining strips 72 are removed, and part of the soil directly outside the detection pile near the abnormal point is obtained, thereby realizing two types of sampling. During the re-inspection, the two types of samples can be tested at the same time, thereby effectively ensuring the accuracy of the test results.

[0027] In summary, by setting up multiple detection piles, it is possible to first realize synchronous initial detection of multiple points and different depths of the soil to be tested, and then cooperate with the laboratory review method to effectively ensure the detection accuracy and make the detection effect of heavy metal content more accurate. In addition, in this process, in conjunction with the sample pre-filling operation, before the detection pile is pre-buried, the sample can be placed in the pre-assimilation strip 7 at the target depth in advance, so that it can gradually assimilate with the surrounding soil during the pre-buried detection process. When the initial inspection is abnormal and the re-inspection is carried out, the pre-assimilation strip 7 can be directly taken out to obtain the sample at the abnormal point. Compared with the existing technology, there is no need for excavation and sampling, which can effectively simplify the excavation and sampling process. That is, the existing technology requires excavation once for pre-buried and excavation again for sampling, while the present application does not require secondary excavation when sampling, thereby reducing the tediousness of sampling, thereby greatly shortening the time span of detection and improving detection efficiency.

[0028] The second implementation method: Based on the first embodiment, this embodiment further improves the pre-assimilation strip 7, and the rest of the parts remain the same as the first embodiment.

[0029] Figure 13 As shown, the restraining strip 72 is an arc-shaped arc arched toward the outside of the side magnetic plate 71, and a plurality of tie ropes 744 are fixedly connected between the pull rod 742 and the plurality of restraining strips 72. The plurality of restraining strips 72 are made of elastic metal sheet material, and the distance between the middle of the outer surface of the restraining strip 72 and the axis of the side magnetic plate 71 is not greater than the radius of the side magnetic plate 71. The pull rod 742 is made of a corrosion-resistant non-elastic material. Figure 14 When subjected to the magnetic attraction of the electromagnetic sheet, the pull rod 742 will pull the multiple binding ropes 744 when it moves, and then the multiple arc-shaped binding strips 72 will deform toward the axis of the pre-assimilation strip 7. On the one hand, it can squeeze the sample inside it and make it relatively hardened, so that the sample is not easy to spill during the removal of the pre-assimilation strip 7; on the other hand, it can loosen the pre-assimilation strip 7 and the surrounding quicksand medium to a certain extent, and at the same time make its outer diameter slightly smaller, reducing the friction force encountered by the pre-assimilation strip 7 when it is taken out, making it easier for the electromagnetic sheet to suck it out of the sample tube 5.

[0030] The third implementation method: This embodiment is based on the first embodiment, with the pre-assimilation sample and related settings changed, and the rest remains consistent with the first embodiment.

[0031] Figure 15 As shown, the pre-assimilated sample is an aggregation capsule, which is located between a plurality of restraining strips 72. A T-shaped groove is bored in the middle of the edge magnetic plate 71, and the T-shaped groove is coaxially arranged with the aggregation capsule. The aggregation capsule includes two positioning hemispheres 92, an outer adsorption layer 91 fixedly connected between the two positioning hemispheres 92, and an inner control capsule 93. The inner control capsule 93 is located in the outer adsorption layer 91, and the inner control capsule 93 is filled with compressed air, so that the inner control capsule 93 is in squeeze contact with the outer adsorption layer 91, and the outer adsorption layer 91 is in a compressed state. A rubber plug 941 is provided at the end of the inner control capsule 93 close to the edge magnetic plate 71. The rubber plug 941 movably passes through the corresponding edge magnetic plate 71 and extends into the T-shaped groove, as shown in FIG. Figure 17 The electromagnetic sheet includes an outer magnetic ring 631 and an inner magnetic sheet 632. The inner magnetic sheet 632 is located on the inner side of the outer magnetic ring 631, and the two are coaxially arranged. A magnetic shielding layer is also provided between the outer magnetic ring 631 and the inner magnetic sheet 632, so that the magnetic fields between the outer magnetic ring 631 and the inner magnetic sheet 632 are not easily affected by each other. A pull rope 942 is also fixedly connected between the rubber plug 941 and the inner magnetic sheet 632, so that the rubber plug 941 is not easily lost after being separated from the extension tube 3, and is convenient for subsequent recycling and reuse. The outer magnetic ring 631 and the inner magnetic sheet 632 correspond to the side magnetic plate 71 and the rubber plug 941 respectively.

[0032] When the heavy metal ion sensor 61 detects that the content of heavy metal ions is gradually increasing but has not yet reached the alarm value, Figure 16, the inner magnetic piece 632 of the corresponding depth can be controlled to be energized first, thereby adsorbing the corresponding rubber plug 941, causing it to gradually separate from the inner control capsule 93, and the gas inside it is gradually released, thereby gradually contacting the compressed state of the outer adsorption layer 91, so that its water absorption is improved. At this time, the water carrying heavy metal ions in the soil will gradually penetrate toward the outer adsorption layer 91, and its adsorption can also accelerate the penetration speed of water. When the heavy metal ion sensor 61 detects that its content is too high and issues a re-inspection reminder to the staff, the aggregation capsule has been gradually assimilated, and then it can be tested. Compared with directly filling the soil, its water absorption is better, and the speed and effect of being assimilated by the surrounding soil are better, so that it can better reflect the heavy metal content of the surrounding soil and effectively ensure the detection accuracy.

[0033] In view of current actual needs, the protection scope of the above-mentioned implementation mode adopted in this application is not limited to this. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the protection scope of the present invention.

Claims

1. A multi-point detection method for heavy metal content in soil, characterized by: The following steps are involved: S1. First, excavate multiple points in the soil where heavy metal contamination may exist, and pre-bury multiple detection piles. At the same time, multiple detection piles are marked. Before pre-burying, the detection piles are pre-filled with samples. The minimum interval between two adjacent detection piles is 1 meter. Multiple detection piles are connected to the external detection terminal signal; S21. After pre-embedding, let it stand for 48 hours until the soil structure gradually recovers and stabilizes. Then, remotely activate the detection function of the detection pile to detect the soil and conduct preliminary detection of heavy metal content at multiple depths and points in real time. S22. When the detection terminal receives the data of the heavy metal content exceeding the standard in the initial detection, it locates the detection pile at the abnormal point according to the data source and takes out the sample pre-filled in the target depth; S3. Conduct targeted re-examination and testing of the sample in the laboratory using a mass spectrometer. If the test results show that the heavy metal content exceeds the standard, targeted treatment will be carried out; The detection pile comprises a positioning cone (2), a plurality of detection sections (1) threadedly connected in sequence, and an extension tube (3) threadedly connected to the top of the uppermost detection section (1), the top cover of the extension tube (3) is provided with a top sealing cover (4), the lowermost detection section (1) is threadedly fixed to the positioning cone (2), the detection section (1) comprises an embedded tube (11), an outer sheath (12) fixedly sleeved on the outer end of the embedded tube (11), a threaded ring (13) fixedly connected to the lower ends of the embedded tube (11) and the outer sheath (12), the outer ends of the embedded tube (11) and the outer sheath (12) are fixedly penetrated by a lofting tube (5), the inner wall of the embedded tube (11) near the lower edge is fixedly mounted with a heavy metal monitoring unit, the heavy metal monitoring unit comprises a fixed inner wall of the embedded tube (11) and a fixed inner wall of the embedded tube (11). A fixedly connected bottom plate (62), a heavy metal ion sensor (61) mounted on the upper end of the bottom plate (62), the detection end of the heavy metal ion sensor (61) movably penetrates the embedded tube (11) and extends to the outside of the embedded tube (11), the lofting tube (5) is movably inserted with a pre-assimilation strip (7) toward the middle of the embedded tube (11), the upper end of the bottom plate (62) is also fixedly connected to a back plate (63), the middle of the back plate (63) is fixedly connected to an electromagnetic sheet, the middle of the electromagnetic sheet is opposite to the pre-assimilation strip (7), the end of the pre-assimilation strip (7) close to the back plate (63) is located outside the lofting tube (5) and is tied with a sample collection rope (8), the upper end of the sample collection rope (8) sequentially penetrates the multiple embedded tubes (11) and the extension tube (3) above and is fixedly connected to the top of the top cover (4); The sample pre-filling process in step S1 is as follows: First, the pre-assimilation sample is filled into the pre-assimilation strip (7), and the quicksand medium is filled into the sample tube (5), and the pre-assimilation strip (7) is buried in the quicksand medium, wherein the quicksand medium comprises 93%-97% silica sand and 3%-7% bentonite by mass.

2. The method for multi-point detection of heavy metal content in soil according to claim 1, characterized in that: When pre-buried, the top of each detection pile is higher than the soil surface, and different marking labels are attached to the exposed parts.

3. The method for multi-point detection of heavy metal content in soil according to claim 2, characterized in that: One end of the lofting tube (5) facing the inside of the embedded tube (11) is a flat surface, and one end of the lofting tube (5) facing the outside of the detection section (1) is a cylindrical surface, and the outer end of the cylindrical surface is provided with a plurality of evenly distributed through holes (501).

4. The multi-point detection method for heavy metal content in soil according to claim 3, characterized in that: The pre-assimilation strip (7) includes a side magnetic plate (71) movably inserted on the flat surface of the sample tube (5), a positioning plate (73) movably inserted on the cylindrical surface of the sample tube (5), and a plurality of restraining strips (72) fixedly connected between the side magnetic plate (71) and the positioning plate (73), wherein the plurality of restraining strips (72) are distributed in a circular array, a limiting groove is cut at the outer end of the side magnetic plate (71), and the connection point between the sample collection rope (8) and the pre-assimilation strip (7) is located in the limiting groove, and the sample is filled in the space surrounded by the side magnetic plate (71), the restraining strip (72) and the positioning plate (73).

5. The multi-point detection method for heavy metal content in soil according to claim 4, characterized in that: The pre-assimilation sample is the soil obtained during pre-embedded excavation at a depth corresponding to the lofting tube (5). A soil-carrying rod is movably passed through the middle of the side magnetic plate (71) and the positioning plate (73). The soil-carrying rod includes a pull rod (742) and a circular magnetic piece (741) and a soil pressing piece (743) respectively fixedly connected to the left and right ends of the pull rod (742). A recess is excavated in the middle of the side magnetic plate (71). The circular magnetic piece (741) contacts the vertical inner wall of the recess. The soil pressing piece (743) is located outside the pre-assimilation strip (7), and the soil pressing piece (743) is an arc that arches toward the side away from the positioning plate (73). When the back plate (63) is energized, it generates magnetic attraction on the circular magnetic piece (741) and the side magnetic plate (71).

6. The multi-point detection method for heavy metal content in soil according to claim 5, characterized in that: The restraining strip (72) is in the shape of an arc that arches outward toward the side magnetic plate (71), and a plurality of restraining ropes (744) are fixedly connected between the pull rod (742) and the plurality of restraining strips (72). The plurality of restraining strips (72) are made of elastic metal sheet material, and the distance between the middle of the outer surface of the restraining strip (72) and the axis of the side magnetic plate (71) is not greater than the radius of the side magnetic plate (71). The pull rod (742) is made of a corrosion-resistant non-elastic material.

7. The multi-point detection method for heavy metal content in soil according to claim 4, characterized in that: The pre-assimilated sample is an aggregation capsule, which is located between a plurality of restraining strips (72). A T-shaped groove is bored in the middle of the edge magnetic plate (71), and the T-shaped groove is coaxially arranged with the aggregation capsule. The aggregation capsule includes two positioning hemispheres (92), an outer adsorption layer (91) fixedly connected between the two positioning hemispheres (92), and an inner control capsule (93). The inner control capsule (93) is located in the outer adsorption layer (91), and is filled with compressed air. The end plug of the inner control capsule (93) close to the edge magnetic plate (71) is provided with a rubber plug (941), and the rubber plug (941) movably passes through the corresponding edge magnetic plate (71) and extends into the T-shaped groove.

8. The multi-point detection method for heavy metal content in soil according to claim 7, characterized in that: The electromagnetic sheet comprises an outer magnetic ring (631) and an inner magnetic sheet (632), the inner magnetic sheet (632) being located on the inner side of the outer magnetic ring (631), and the two being coaxially arranged, a magnetic shielding layer being further arranged between the outer magnetic ring (631) and the inner magnetic sheet (632), a pull rope (942) being further fixedly connected between the rubber plug (941) and the inner magnetic sheet (632), the outer magnetic ring (631) and the inner magnetic sheet (632) corresponding to the edge magnetic plate (71) and the rubber plug (941), respectively.

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