Sampling drilling tool for keeping oxidation-reduction potential of soil in-situ stratum

Abstract

The invention provides a sampling drilling tool for keeping soil in-situ stratum oxidation-reduction potential, which comprises a drilling main body, a first drilling rod, a second drilling rod and a propelling main body, and the first drilling rod, the second drilling rod and the propelling main body are respectively provided with an inner cavity; the first drill rod is provided with a first gas transmission channel communicated with an inner cavity of the first drill rod, the second drill rod is provided with a second gas transmission channel, and the propelling body is provided with a third gas transmission channel. During use, the drilling main body, the first drilling rod, the N second drilling rods and the propelling main body are sequentially connected from bottom to top, inner cavities of the drilling main body, the first drilling rod, the N second drilling rods and the propelling main body are sequentially communicated to form a sampling cavity, and the third gas transmission channel, the second gas transmission channel, the first gas transmission channel and the sampling cavity are sequentially communicated; n is an integer greater than or equal to 0. According to the sampling drilling tool for maintaining the oxidation-reduction potential of the soil in-situ stratum, high-fidelity collection of soil samples can be achieved, and the oxidation-reduction potential of the soil in-situ stratum is maintained.

Description

Technical Field

[0001] The invention belongs to the technical field of pollution control and treatment, and in particular relates to a sampling drill for maintaining the redox potential of an in-situ soil formation. Background Art

[0002] In the sampling work of contaminated sites, being able to collect soil samples with the same redox potential as the original strata is a prerequisite for the investigation, control and treatment and remediation of contaminated sites. The sampling process of traditional static pressure sampling drills, vibration sampling drills and rotary sampling drills is highly disturbed. During the sample collection process or after the sample is taken out of the sampling drill, it comes into contact with oxygen in the atmosphere for a short time. Some organic carbon, divalent iron and divalent manganese in the soil are easily oxidized by oxygen in the air, changing the redox state of the soil, resulting in a difference between the redox potential of the collected soil samples and that in the original strata. The redox potential of the soil will affect the metabolic process of microorganisms in the soil or groundwater, causing changes in the structure of the biological community in the soil, thereby changing the transformation process of heavy metals or organic matter in the soil or groundwater. In addition, under the oxidizing action of oxygen in the air, some components in the soil undergo chemical reactions, changing the chemical form of clay minerals on the surface of soil particles, thereby affecting the migration and transportation process of heavy metals or organic matter in the soil or groundwater. However, there is currently no sampling drill that can effectively maintain the redox potential of the soil in the saturated zone below the groundwater level, making it difficult to effectively obtain high-fidelity soil samples with the same redox potential as the in-situ strata, hindering the efficient implementation of contaminated site investigations and remediation work. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a sampling drill tool for maintaining the redox potential of an in-situ soil formation, which can realize high-fidelity collection of soil samples and maintain the redox potential of an in-situ soil formation.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides a sampling drill tool for maintaining the redox potential of an in-situ stratum of soil, comprising a drilling body, a first drill rod, a second drill rod and a propulsion body, wherein the first drill rod, the second drill rod and the propulsion body all have inner cavities; the first drill rod is provided with a first gas transmission channel connected with its inner cavity, the second drill rod is provided with a second gas transmission channel, and the propulsion body is provided with a third gas transmission channel; when in use, the drilling body, the first drill rod, N second drill rods and the propulsion body are sequentially connected from bottom to top, the inner cavities of the drilling body, the first drill rod, the N second drill rods and the propulsion body are sequentially connected to form a sampling cavity, and the third gas transmission channel, the second gas transmission channel, the first gas transmission channel and the sampling cavity are sequentially connected; N is an integer greater than or equal to 0.

[0005] As a further improvement of the present invention, the first drill rod includes a first hollow rod body, one end of the first hollow rod body is provided with a first threaded boss for connecting to the drilling body, and the other end is provided with a second threaded boss for connecting to the second drill rod; the inlet of the first gas transmission channel is located on the end surface of the second threaded boss, and the outlet is located on the inner wall surface of the first threaded boss; a first one-way valve is provided at the outlet of the first gas transmission channel.

[0006] As a further improvement of the present invention, a half circle of first air guide grooves is provided on the end surface of the second threaded protrusion along the circumference of the inner cavity, and the first air guide grooves are connected to the inlet of the first air delivery channel.

[0007] As a further improvement of the present invention, the end face of the first threaded boss is provided with a circle of first sealing ring, the end face of the second threaded boss is provided with two circles of second sealing rings, and the inlet of the first gas transmission channel is located between the two circles of second sealing rings.

[0008] As a further improvement of the present invention, the second drill rod includes a second hollow rod body, one end of the second hollow rod body is provided with a first threaded groove for connecting to the first drill rod, and the other end is provided with a third threaded boss adapted to the first threaded groove; the inlet of the second gas transmission channel is located on the end surface of the third threaded boss, and the outlet is located on the bottom surface of the first threaded groove.

[0009] As a further improvement of the present invention, a half-circle second air guide groove is provided on the end face of the third threaded protrusion along the circumference of the inner cavity, and the second air guide groove is connected to the inlet of the second air transmission channel; a half-circle third air guide groove is provided on the bottom surface of the first threaded groove along the circumference of the inner cavity, and the third air guide groove is connected to the outlet of the second air transmission channel.

[0010] As a further improvement of the present invention, the end face of the third threaded protrusion is provided with two circles of third sealing rings, and the inlet of the second gas transmission channel is located between the two circles of third sealing rings; the bottom surface of the first threaded groove is provided with two circles of fourth sealing rings, and the outlet of the second gas transmission channel is located between the two circles of fourth sealing rings.

[0011] As a further improvement of the present invention, the propulsion body includes a cover body and a hollow tube body, the end surface of the cover body is provided with a protrusion for inserting one end of the hollow tube body, and the other end of the hollow tube body is provided with a second threaded groove for connecting with the second drill rod; the inlet of the third gas transmission channel is located on the outer wall surface of the hollow tube body, and the outlet is located on the bottom surface of the second threaded groove; a second one-way valve is provided at the inlet of the third gas transmission channel.

[0012] As a further improvement of the present invention, a half circle of fourth air guide grooves is provided on the groove bottom surface of the second thread groove along the circumference of the inner cavity, and the fourth air guide grooves are connected to the outlet of the third air delivery channel.

[0013] As a further improvement of the present invention, the end face of the hollow tube body is provided with a circle of fifth sealing ring; the bottom surface of the groove of the second threaded groove is provided with two circles of sixth sealing rings, and the outlet of the third gas transmission channel is located between the two circles of sixth sealing rings.

[0014] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: The sampling drill tool for maintaining the redox potential of the in-situ formation of soil provided by the present invention, when in use, the drilling body, the first drill rod, the second drill rod and the propulsion body are connected in sequence from bottom to top, the sampling tube is installed in the first drill rod through the propulsion body and the second drill rod, the drilling rig presses down the propulsion body, pushes the drilling body, the first drill rod and the second drill rod to be gradually pressed into the formation, the soil sample enters the sampling tube, after the sampling tube is full, a new sampling tube is replaced, and by adding the second drill rod, the downward pressure depth is continuously increased to collect soil samples within a predetermined depth range. When collecting soil samples below the groundwater burial depth, inert gas is introduced from the inlet of the third gas transmission channel of the propulsion body, and the inert gas enters the sampling cavity through the third gas transmission channel of the propulsion body, the second gas transmission channel of the second drill rod, and the first gas transmission channel of the first drill rod in turn, so that the sampling cavity is filled with inert gas, and the soil drilled under the body is isolated from the atmosphere. A sampling tube filled with inert gas is installed, and drilling is performed downward, so that the soil sample entering the sampling tube is never in contact with the atmosphere, thereby effectively maintaining the redox potential of the saturated zone soil below the groundwater level, and realizing high-fidelity collection of soil samples. The sampling drill provided by the present invention can be used in conjunction with an existing conventional drilling rig power unit, without the need to be equipped with a special power unit, and the sampling cost is low. The sampling drill provided by the present invention can also be used for the collection of conventional soil samples (i.e., soil samples that do not need to maintain the redox potential of the in-situ stratum of the soil), meeting a wider range of sampling needs and being suitable for more application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a cross-sectional view of a first drill rod in an embodiment of the present invention; Figure 2 is a top view of a first drill rod in an embodiment of the present invention; Figure 3 is a bottom view of a first drill rod in an embodiment of the present invention; Figure 4 is a cross-sectional view of a second drill rod in an embodiment of the present invention; Figure 5 is a top view of a second drill rod in an embodiment of the present invention; Figure 6 is a bottom view of the second drill rod in the embodiment of the present invention; Figure 7 is a cross-sectional view of a propulsion body in an embodiment of the present invention; Figure 8is a top view of a propulsion body in an embodiment of the present invention; Fig. 9 is a bottom view of a propulsion body in an embodiment of the present invention; Fig.10 It is a cross-sectional view of the drilling body in the embodiment of the present invention.

[0016] In the figure: the first hollow rod body 110, the first gas transmission channel 111, the first gas guide groove 112, the second sealing ring 113, the first sealing ring 114, the first one-way valve 115, the second hollow rod body 120, the second gas transmission channel 121, the second gas guide groove 122, the third gas guide groove 123, the third sealing ring 124, the fourth sealing ring 125, the third gas transmission channel 21, the cover body 20, the hollow tube body 22, the fourth gas guide groove 23, the fifth sealing ring 24, the sixth sealing ring 25, the second one-way valve 26, the conical hollow drill bit 31, and the seventh sealing ring 32. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is described in detail below.

[0018] An embodiment of the present invention provides a sampling drill tool for maintaining the redox potential of the in-situ formation of the soil, including a drilling body, a first drill rod, a second drill rod and a propulsion body, wherein the first drill rod, the second drill rod and the propulsion body all have an inner cavity. The first drill rod is provided with a first gas transmission channel 111 connected to its inner cavity, the second drill rod is provided with a second gas transmission channel 121, and the propulsion body is provided with a third gas transmission channel 21. Wherein, N is an integer greater than or equal to 0, and N is determined according to the on-site sampling depth. The sampling drill tool of the embodiment of the present invention also includes a sampling tube and a mandrel. Preferably, the length of the sampling tube, the length of the first drill rod, the length of the second drill rod and the length of the mandrel are all equal, then the number of the second drill rods is equal to the number of the mandrels.

[0019] When in use, the drilling body, the first drill rod, N second drill rods and the propulsion body are connected in sequence, the drilling body is located at the bottom, and the propulsion body is located at the top. Thus, the inner cavities of the propulsion body, N second drill rods and the first drill rod are connected in sequence, and the first gas transmission channel 111, N second gas transmission channels 121 and the third gas transmission channel 21 are connected to the sampling cavity in sequence. The N push rods are connected from top to bottom in sequence, and the bottom end of the bottom push rod is connected to the top of the sampling tube. The push rod and the sampling tube are inserted into the sampling cavity, and finally the sampling tube is located in the inner cavity of the first drill rod. The drilling rig presses down the propulsion body, pushing the drilling body, the first drill rod and the second drill rod gradually into the formation, and the soil sample enters the sampling tube. After the sampling tube is full, the propulsion body is disassembled, the full sampling tube is taken out, the empty sampling tube is installed, and another second drill rod is installed above the second drill rod at the top, and the propulsion body is installed. By adding a second drill rod, the downward pressure depth is continuously increased to collect soil samples. When collecting soil samples below the groundwater burial depth, inert gas is introduced from the inlet of the third gas transmission channel of the propulsion body, and the inert gas enters the sampling cavity through the third gas transmission channel of the propulsion body, the second gas transmission channel of the second drill rod and the first gas transmission channel of the first drill rod in sequence, so that the sampling cavity is filled with inert gas, so that the soil under the drilled body is isolated from the atmosphere, and a sampling tube filled with inert gas is installed, and drilling is carried out downward, so that the soil sample entering the sampling tube is never in contact with the atmosphere, thereby effectively maintaining the redox potential of the soil in the saturated zone below the groundwater level and realizing high-fidelity collection of soil samples.

[0020] like Fig.10 As shown, the drilling body includes a conical hollow drill bit 31, the upper inner wall of the conical hollow drill bit 31 is provided with threads, the lower inner wall is provided with a circle of limiting protrusions, and the upper surface of the limiting protrusions is provided with a circle of seventh sealing rings 32.

[0021] like Figure 1 As shown, the first drill rod includes a first hollow rod body 110, and one end (bottom end) of the first hollow rod body 110 is provided with a first threaded boss for connecting with the drilling body. When in use, the first threaded boss is inserted into the conical hollow drill bit and is threadedly connected with the conical hollow drill bit, and the bottom end of the first threaded boss abuts against the limiting protrusion. The other end (top end) of the first hollow rod body is provided with a second threaded boss for connecting with the second drill rod. The inlet of the first gas transmission channel 111 is located on the end surface of the second threaded boss, and the outlet is located on the inner wall surface of the first threaded boss. A first one-way valve 115 is provided at the outlet of the first gas transmission channel 111, which only allows the gas in the first gas transmission channel 111 to flow out, and does not allow the gas to enter the first gas transmission channel 111. It can effectively prevent soil gas containing pollutants in the formation from entering the first gas transmission channel 111. After entering, the polluted gas will be adsorbed on the surface of the first gas transmission channel 111 and pollute the first gas transmission channel 111.

[0022] Preferably, Figure 2 As shown, a half circle of first air guide groove 112 is provided on the end surface of the second threaded protrusion along the circumference of the inner cavity, and the first air guide groove 112 is connected to the inlet of the first air delivery channel.

[0023] Preferably, Figure 2 As shown, two circles of second sealing rings 113 are arranged on the end surface of the second threaded protrusion, and the inlet of the first gas transmission channel is located between the two circles of second sealing rings. Figure 3 As shown, a circle of first sealing ring 114 is provided on the end surface of the first threaded boss. After the first drill rod is connected to the drilling body, the first sealing ring 114 cooperates with the seventh sealing ring 32 to prevent groundwater from entering the cavity of the first drill rod through the connection between the first threaded boss and the drilling body, and at the same time, it can also prevent polluted gas dissolved in groundwater from entering the cavity of the drill rod, causing contamination of the inner wall of the cavity of the drill rod.

[0024] As a preferred example, Figure 4 As shown, the second drill rod includes a second hollow rod body 120, one end (bottom end) of the second hollow rod body 120 is provided with a first thread groove for connecting with the first drill rod, and the first thread groove is matched with the second thread protrusion. The other end (top end) of the second hollow rod body 120 is provided with a third thread protrusion matched with the first thread groove, so that multiple second hollow rod bodies 120 can be connected in sequence. The inlet of the second gas transmission channel 121 is located on the end surface of the third thread protrusion, and the outlet is located on the bottom surface of the groove of the first thread groove.

[0025] Preferably, Figure 5 As shown, a half circle of second air guide groove 122 is provided on the end surface of the third threaded protrusion along the circumference of the inner cavity, and the second air guide groove 122 is connected to the inlet of the second air delivery channel. Figure 6 As shown, a half circle of the third gas guide groove 123 is provided on the bottom surface of the groove of the first thread groove along the circumference of the inner cavity, and the third gas guide groove 123 is connected to the outlet of the second gas transmission channel. When the second drill rod is connected to the first drill rod, the first gas guide groove 112 is connected to the third gas guide groove 123 correspondingly, the first gas transmission channel 111 of the first drill rod is connected to the first gas guide groove 112, and the second gas transmission channel 121 of the second drill rod is connected to the third gas guide groove, so that even if the inlet of the first gas transmission channel of the first drill rod is not opposite to the outlet of the second gas transmission channel of the second drill rod, the first gas transmission channel and the second gas transmission channel can be connected, and the inert gas can be well transmitted. When two adjacent second drill rods are connected, the second gas guide groove 122 is connected to the third gas guide groove 123 correspondingly, the second gas transmission channel 121 on the upper second drill rod is connected to the third gas guide groove 123, and the second gas transmission channel 121 on the lower second drill rod is connected to the second gas guide groove. Therefore, even if the outlet and inlet of the second gas transmission channels of the two adjacent first drill rods are not opposite to each other, the second gas transmission channels of the two adjacent second drill rods can be connected, so that the inert gas can be well transmitted.

[0026] Preferably, Figure 5 As shown, two circles of third sealing rings 124 are arranged on the end surface of the third threaded protrusion, and the inlet of the second gas transmission channel is located between the two circles of third sealing rings 124. Figure 6 As shown, two circles of fourth sealing rings 125 are provided on the bottom surface of the first thread groove, and the outlet of the second gas transmission channel is located between the two circles of fourth sealing rings 125. After the first drill rod is connected to the second drill rod, the two circles of second sealing rings cooperate with the two circles of fourth sealing rings, and after two adjacent second drill rods are connected, the two circles of third sealing rings cooperate with the two circles of fourth sealing rings to prevent the inert gas from leaking at the threaded boss or the threaded groove connection, which causes a small inert gas flow rate at the gas outlet of the first drill rod or no gas is discharged, thereby failing to achieve the expected effect of removing all air in the drill rod cavity.

[0027] like Figure 7 As shown, the propulsion body includes a cover body 20 and a hollow tube body 22. The end face of the cover body 20 is provided with a protrusion for inserting one end (top end) of the hollow tube body 22, and the other end (bottom end) of the hollow tube body 22 is provided with a second threaded groove for connecting to the second drill pipe, and the second threaded groove is adapted to the third threaded protrusion. The inlet of the third gas transmission channel 21 is located on the outer wall surface of the hollow tube body, and the outlet is located on the groove bottom surface of the second threaded groove. The cover body 20 and the hollow tube body 22 of the propulsion body are detachably connected, which is convenient for plugging and unplugging the cover body 20, ensuring the high-quality completion of the operation processes such as emptying the air in the drill pipe cavity and removing the sampling tube, and significantly improving the sampling efficiency. A second one-way valve 26 is provided at the inlet of the third gas transmission channel, which only allows exogenous gas to enter the third gas transmission channel 21, and does not allow the gas in the third gas transmission channel 21 to flow out. After the propulsion body, the second drill body and the first drill body are connected, the second one-way valve 26 is used in conjunction with the first one-way valve 115 to effectively prevent soil gas containing pollutants in the formation from entering the gas transmission channel, and prevent the polluted gas from being adsorbed on the surface of the gas transmission channel after entering, causing pollution to the gas transmission channel.

[0028] Preferably, Fig. 9 As shown, a half circle of the fourth gas guide groove 23 is provided on the bottom surface of the second thread groove along the circumference of the inner cavity of the hollow tube body, and the fourth gas guide groove 23 is connected to the outlet of the third gas transmission channel. The propulsion body is connected to the second drill rod, the fourth gas guide groove 23 is correspondingly connected to the second gas guide groove 122, the third gas transmission channel 21 of the propulsion body is connected to the fourth gas guide groove 23, and the second gas transmission channel 121 of the second drill rod is connected to the second gas guide groove, so that even if the outlet of the third gas transmission channel is not opposite to the inlet of the second gas transmission channel, the third gas transmission channel and the second gas transmission channel can be connected, and the inert gas can be well transmitted.

[0029] During the sampling process, the two ends of the drill rod are more likely to stick to the contaminated soil, causing the gas guide groove to be blocked, and distilled water is needed to be used for cleaning on site. Therefore, in order to improve the sampling effect and ensure the complete connectivity of the gas transmission channel between the two adjacent drill rods, all gas guide grooves are set to half a circle.

[0030] Preferably, Figure 8 As shown, a fifth sealing ring 24 is provided on the end surface of the hollow tube. After the cover 20 and the hollow tube 22 are connected, the fifth sealing ring can prevent the inert gas from leaking from the connection between the cover and the hollow tube, thereby reducing the flow of the inert gas entering the sampling cavity. Fig. 9 As shown, two circles of sixth sealing rings 25 are arranged on the bottom surface of the second thread groove, and the outlet of the third gas transmission channel is located between the two circles of sixth sealing rings 25. After the second drill pipe is connected to the propulsion body, the two circles of third sealing rings and the two circles of sixth sealing rings cooperate to prevent the inert gas from leaking at the threaded boss or the threaded groove connection, which causes a small inert gas flow rate at the gas outlet of the first drill pipe or no gas is discharged, thereby failing to achieve the expected effect of removing all the air in the drill pipe cavity.

[0031] The embodiment of the present invention adopts two types of drill rods, namely, a first drill rod and a second drill rod. The first drill rod is mainly used to fix and protect the sampling tube so that the sampling tube does not deform or damage during the sampling process. Therefore, the material requirements of the first drill rod are higher to ensure the strength and rigidity of the first drill rod. The conical hollow drill bit 31 is prone to deformation or damage during use. In order to facilitate quick replacement, the lower end of the first drill rod is set in the form of a threaded boss. The connection between the first drill rod and the drilling body is achieved by inserting the conical hollow drill bit. This can effectively avoid the situation where the conical hollow drill bit 31 cannot be removed after being damaged due to being embedded in the lower end of the first drill rod, thereby causing the first drill rod to be damaged, thereby reducing the equipment maintenance cost during the sampling process. The second drill rod is mainly used to connect the first drill rod and the propulsion body. The load of the drilling rig power unit and the effect of the soil layer on it are significantly lower than those of the first drill rod. Therefore, its strength and rigidity requirements are lower than those of the first drill rod. In addition, the part of the second drill rod that is subjected to the greatest impact load is the top part connected to the propulsion body. Therefore, the top part of the second drill rod is designed to be in the form of a threaded protrusion. Compared with the use of a threaded groove, this can effectively avoid the situation where the propulsion body cannot be removed after being damaged because it is embedded in the top end of the second drill rod, thereby reducing the equipment maintenance cost during the sampling process.

[0032] The workflow of the sampling drill tool of this embodiment is as follows: S1, connect the bottom end of the first drill rod to the drilling body, install the first sampling tube into the first drill rod, and then connect the top end of the first drill rod to the propulsion body. Operate the drilling rig hydraulic drive unit to press the first drill rod into the formation. Separate the propulsion body from the first drill rod and take out the first sampling tube filled with soil samples. S2, connect the bottom end of the first second drill rod to the top end of the first drill rod, install the second sampling tube with a top rod installed into the first drill rod, and then connect the top end of the first second drill rod to the propulsion body. Operate the drilling rig drive unit to press the first second drill rod into the formation. Separate the propulsion body from the first second drill rod and take out the second sampling tube filled with soil samples.

[0033] S3, add second drill rods in sequence, replace a sampling tube each time a second drill rod is added, press the added second drill rod into the formation, take out the sampling tube filled with soil sample, until the bottom of the drill body reaches the groundwater burial depth.

[0034] S4, install the M+pth second drill rod on the top of the Mth second drill rod, connect the top of the M+1th second drill rod to the propulsion body, and separate the cover body 20 from the hollow tube body 22. M is an integer greater than or equal to 1, and p=1.

[0035] S5, nitrogen is introduced from the inlet of the third gas supply channel of the propulsion body. When the volume of the introduced nitrogen is 3 to 5 times the sum of the inner cavity volumes of M+p second drill rods and 1 first drill rod, the introduction of nitrogen is stopped.

[0036] S6, insert the M+p+1th sampling tube with M+p top rods installed into the first drill pipe from the opening at the top of the hollow tube body 22, and then install the cover body 20 on the top of the hollow tube body 22. Before installation, the M+p+1th sampling tube is filled with nitrogen.

[0037] S7, operate the drilling rig hydraulic drive unit to press the M+pth second drill rod into the formation.

[0038] S8, separate the propulsion body from the top of the M+pth second drill rod, and take out the M+p+1th sampling tube filled with soil sample. Thus, the pth soil sample below the groundwater level is obtained. The value of p increases by 1.

[0039] S9, repeating steps S4 to S8 until all soil samples within a predetermined depth range below the groundwater level are taken out.

[0040] S10, operate the drilling rig driving unit to pull the sampling drill tool out of the formation, disassemble it and flush it.

[0041] The basic principles, main features and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above specific embodiments, and the descriptions in the above specific embodiments and the specification are only for further illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed for protection.

Claims

1. A sampling drill for maintaining the redox potential of soil in situ strata, characterized in that: The invention comprises a drilling body, a first drill rod, a second drill rod and a propulsion body, wherein the first drill rod, the second drill rod and the propulsion body all have inner cavities; the first drill rod is provided with a first gas transmission channel (111) connected to its inner cavity, the second drill rod is provided with a second gas transmission channel (121), and the propulsion body is provided with a third gas transmission channel (21); when in use, the drilling body, the first drill rod, N second drill rods and the propulsion body are sequentially connected from bottom to top, the inner cavities of the drilling body, the first drill rod, the N second drill rods and the propulsion body are sequentially connected to form a sampling cavity, and the third gas transmission channel (21), the second gas transmission channel (121), the first gas transmission channel (111) and the sampling cavity are sequentially connected; N is an integer greater than or equal to 0.

2. The sampling drill for maintaining the redox potential of the soil in situ strata according to claim 1, characterized in that: The first drill rod comprises a first hollow rod body (110); one end of the first hollow rod body (110) is provided with a first threaded boss for connecting to a drilling body, and the other end is provided with a second threaded boss for connecting to a second drill rod; the inlet of the first gas transmission channel (111) is located on the end surface of the second threaded boss, and the outlet is located on the inner wall surface of the first threaded boss; and a first one-way valve (115) is provided at the outlet of the first gas transmission channel.

3. The sampling drill for maintaining the redox potential of the soil in situ strata according to claim 2, characterized in that: A half circle of first air guide grooves (112) are provided on the end surface of the second threaded protrusion along the circumference of the inner cavity, and the first air guide grooves (112) are connected to the inlet of the first air delivery channel.

4. The sampling drill for maintaining the redox potential of the soil in situ strata according to claim 2, characterized in that: The end surface of the first threaded protrusion is provided with a circle of first sealing ring (114), the end surface of the second threaded protrusion is provided with two circles of second sealing rings (113), and the inlet of the first gas transmission channel is located between the two circles of second sealing rings.

5. The sampling drill for maintaining the redox potential of the soil in situ strata according to claim 1, characterized in that: The second drill rod comprises a second hollow rod body (120); one end of the second hollow rod body (120) is provided with a first thread groove for connecting to the first drill rod, and the other end is provided with a third thread protrusion adapted to the first thread groove; the inlet of the second gas transmission channel (121) is located on the end surface of the third thread protrusion, and the outlet is located on the bottom surface of the first thread groove.

6. The sampling drill for maintaining the redox potential of the soil in situ strata according to claim 5, characterized in that: A half circle of second air guide grooves (122) are provided on the end surface of the third threaded protrusion along the circumference of the inner cavity, and the second air guide grooves (122) are communicated with the inlet of the second air transmission channel; a half circle of third air guide grooves (123) are provided on the bottom surface of the first threaded groove along the circumference of the inner cavity, and the third air guide grooves (123) are communicated with the outlet of the second air transmission channel.

7. The sampling drill for maintaining the redox potential of the soil in situ strata according to claim 5, characterized in that: The end surface of the third threaded protrusion is provided with two circles of third sealing rings (124), and the inlet of the second gas transmission channel is located between the two circles of third sealing rings (124); the bottom surface of the first threaded groove is provided with two circles of fourth sealing rings (125), and the outlet of the second gas transmission channel is located between the two circles of fourth sealing rings (125).

8. The sampling drill for maintaining the redox potential of the soil in situ strata according to claim 1, characterized in that: The propulsion body comprises a cover body (20) and a hollow tube body (22); the end surface of the cover body (20) is provided with a protrusion for inserting one end of the hollow tube body (22); the other end of the hollow tube body (22) is provided with a second threaded groove for connecting to a second drill rod; the inlet of the third gas transmission channel (21) is located on the outer wall surface of the hollow tube body, and the outlet is located on the bottom surface of the second threaded groove; a second one-way valve (26) is provided at the inlet of the third gas transmission channel.

9. The sampling drill for maintaining the redox potential of the soil in situ strata according to claim 8, characterized in that: A half circle of fourth air guide grooves (23) are provided on the groove bottom surface of the second thread groove along the circumference of the inner cavity, and the fourth air guide grooves (23) are connected to the outlet of the third air delivery channel.

10. The sampling drill for maintaining the redox potential of the soil in situ strata according to claim 8, characterized in that: The end surface of the hollow tube body is provided with a circle of fifth sealing ring (24); the bottom surface of the second thread groove is provided with two circles of sixth sealing ring (25), and the outlet of the third gas transmission channel is located between the two circles of sixth sealing ring (25).

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