Sampling and storing method for keeping oxidation-reduction state of soil in-situ stratum

Abstract

The invention provides a sampling and storing method for keeping a soil in-situ stratum oxidation-reduction state, which comprises the following steps: step 10, drilling to a position of underground water burial depth, and forming a preformed hole above the water level of underground water; 20, the protective sleeve is installed in the preformed hole, and inert gas is introduced into the protective sleeve till an inner cavity of the protective sleeve is filled with the inert gas; step 30, a high-fidelity sampling drilling tool is adopted to penetrate through the protective sleeve to collect downwards to obtain a soil sample within a preset depth range below the water level of the underground water; and step 40, collecting the temperature of the depth position of each section of soil sample in the stratum in real time, and storing each section of soil sample in a corresponding temperature environment. According to the sampling and storing method for keeping the oxidation-reduction state of the soil in-situ stratum, high-fidelity collection of soil samples below the water level of underground water can be achieved, and the oxidation-reduction potential of the soil in-situ stratum is kept.

Description

Technical Field

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

[0002] The efficient drilling, collection and preservation of soil samples consistent with the redox state of the in-situ strata of the contaminated site is the key basis for conducting contaminated site investigations, risk remediation and safe development and utilization. However, during the sampling process of the traditional sampling drill, the sampling drill tool is in contact with the atmospheric environment, and after the sample is taken out of the sampling drill tool, the soil sample is often quickly exposed to the atmosphere and comes into contact with active components such as oxygen and carbon dioxide in the air. Some components in the soil, such as organic carbon, divalent iron, and divalent manganese, are easily oxidized by oxygen in the air, thereby changing the redox state of the soil. This causes the redox potential of the collected soil samples to differ from that in the original strata, making it impossible to obtain soil samples consistent with the redox state of the in-situ strata. A large number of studies have shown that the redox potential of the soil has an important influence on the metabolic process of microorganisms in the soil and groundwater, which in turn leads to changes in the structure of the biological community in the soil and affects the transformation process of heavy metals or organic matter in the soil and groundwater. In addition, oxygen in the air will also cause chemical reactions in some components of the soil, change the physical phase of clay minerals on the surface of soil particles, and affect the migration and transportation process of heavy metals or organic matter in the soil and groundwater. In addition, soil temperature has a significant impact on the structure of the biological community in the soil, thereby affecting the redox potential of the soil. Currently, there is a lack of sampling drills that can effectively maintain the redox potential of the saturated zone below the groundwater level, as well as matching sample preservation methods. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a sampling and storage method for maintaining the redox state of the in-situ strata of soil, which can achieve high-fidelity collection of soil samples below the groundwater level and maintain the redox potential of the in-situ strata of soil.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides a sampling and storage method for maintaining the redox state of an in-situ soil stratum, comprising the following steps: Step 10, drilling to the groundwater depth, forming a pre-formed hole above the groundwater level; Step 20, installing the protective sleeve into the pre-formed hole, and introducing an inert gas into the protective sleeve until the inner cavity of the protective sleeve is filled with the inert gas; Step 30, using a high-fidelity sampling drill to collect soil samples within a predetermined depth range below the groundwater level through the protective casing; Step 40, collecting the temperature of each soil sample at the depth in the stratum in real time, and storing each soil sample in a corresponding temperature environment.

[0005] As a further improvement of the present invention, the high-fidelity sampling drill tool includes a drilling body, a first drill rod, a propulsion body and a sampling tube, and the drilling body, the first drill rod and the propulsion body all have an inner cavity; the drilling body is provided with a third gas transmission channel connected to its inner cavity, the first drill rod is provided with a first gas transmission channel, and the propulsion body is provided with a second gas transmission channel; when in use, the drilling body, N first drill rods and the propulsion body are connected in sequence from bottom to top, the inner cavities of the drilling body, N first drill rods and the propulsion body are connected in sequence to form a sampling cavity, and the second gas transmission channel, the first gas transmission channel, the third gas transmission channel and the sampling cavity are connected in sequence; the sampling tube is installed in the inner cavity of the first drill rod at the bottom; N is an integer greater than or equal to 1.

[0006] As a further improvement of the present invention, the propulsion body includes a main body and a cover body having a buffer cavity, the cover body is movably connected to the upper end of the main body; the second gas transmission channel is arranged on the side wall of the main body; the upper and lower ends of the main body both have openings, and a sealing plate is provided at the upper opening of the main body; a limiting hole for placing a sealing tube sleeve with an open top and a closed bottom is provided in the buffer cavity, and the side wall of the sealing tube sleeve is provided with a gas transmission port that is connected to the second gas transmission channel and extends downward from the outside to the inside.

[0007] As a further improvement of the present invention, the step 30 specifically includes: Step 301, insert the drilling body into the protective casing from the top of the protective casing, and sequentially install the first, second, ..., nth first drill rods on the top of the drilling body until the bottom end of the drilling body reaches the groundwater burial depth and the bottom end of the nth first drill rod is located near the ground; n is an integer greater than or equal to 1; Step 302, install the propulsion body at the top of the nth first drill rod, remove the cover body, and open the sealing plate; install the first sampling tube installed with n-1 push rods from the upper end opening of the body, so that the first sampling tube is located in the inner cavity of the first drill rod at the bottom; Step 303, install the first sealing tube sleeve into the buffer cavity of the propulsion body, close the sealing plate; introduce inert gas from the inlet of the second gas transmission channel of the propulsion body until the sampling cavity is filled with inert gas; install the cover body; Step 304, the propulsion body is pushed down, the n first drill rods move downward, and the soil sample enters the first sampling tube; when the Nth first drill rod is completely pressed into the formation, the first sampling tube is filled with the soil sample; Step 305, remove the cover body, lift the sampling tube filled with soil sample upward, when the bottom end of the sampling tube reaches the buffer cavity of the propulsion body, open the sealing plate, move the bottom end of the sampling tube to the top of the sealing tube sleeve, and press the bottom end of the sampling tube into the sealing tube sleeve; take out the sampling tube with the air duct sleeve, number it, and obtain the first section of soil sample below the groundwater level; Step 306, separate the propulsion body from the nth first drill rod, and install the n+1th first drill rod on the top of the nth first drill rod; p=1; Step 307, install a propulsion body at the top of the n+pth first drill rod; remove the cover body and open the sealing plate; install the p+1th sampling tube installed with the n+p-1th push rod from the upper end opening of the body, so that the p+1th sampling tube is located in the inner cavity of the first drill rod at the bottom; Step 308, install the p+1th sealing tube sleeve into the buffer cavity of the propulsion body, close the sealing plate; introduce inert gas from the inlet of the second gas transmission channel of the propulsion body until the sampling cavity is filled with inert gas; install the cover body; Step 309, the propulsion body is pushed down, the n+p first drill rods move downward, and the soil sample enters the p+1th sampling tube; when the n+pth first drill rods are all pressed into the formation, the p+1th sampling tube is filled with soil samples; Step 310, remove the cover body, lift the sampling tube filled with soil sample upward, when the bottom end of the sampling tube reaches the buffer cavity of the propulsion body, open the sealing plate, move the bottom end of the sampling tube to the top of the sealing sleeve, and press the bottom end of the sampling tube into the sealing sleeve; take out the sampling tube with the sealing sleeve, number it, and obtain the p+1th section of soil sample below the groundwater level; the value of p increases by 1; Step 311, repeating steps 307 to 310 until soil samples within a predetermined depth range are taken out.

[0008] As a further improvement of the present invention, the step 40 specifically includes: The middle of each soil sample at the depth of the original stratum is selected as the temperature measuring point corresponding to each soil sample, and temperature sensors are installed on the bracket according to the distribution of each temperature measuring point, and each temperature measuring point corresponds to a temperature sensor; The bracket is placed in the sampling cavity of the high-fidelity sampling drill, and the bottom end of the bracket is embedded in the soil at a preset depth, so that each temperature sensor is located at the depth position of the middle of each soil sample in the original formation; Pull out the high-fidelity sampling drill and protective casing, bury the bracket in the soil layer, and seal the pre-drilled hole; The temperature of each section of soil sample in the original stratum is measured by a temperature sensor, and each section of soil sample is placed in a corresponding temperature environment for storage; according to the measurement data of the temperature sensor, the storage temperature of each section of soil sample is adjusted in real time.

[0009] As a further improvement of the present invention, before the sampling tube is installed in the first drill rod, an inert gas is first introduced into the sampling tube until the sampling tube is filled with the inert gas.

[0010] As a further improvement of the present invention, the sampling tube includes a hollow tube body, a top plug is fixedly installed on the top of the hollow tube body, a first air guide channel is provided on the top plug, one end of the first air guide channel is connected to the inner cavity of the hollow tube body, and the other end is provided with a first one-way valve; a piston is provided in the hollow tube body; an inflation plug is detachably installed at the bottom end of the hollow tube body, a second air guide channel is provided on the inflation plug, one end of the second air guide channel is provided with a second one-way valve, and the other end is provided with an air guide needle; when the inflation plug is installed at the bottom end of the hollow tube body, the air guide needle passes through the piston and is connected to the inner cavity of the hollow tube body.

[0011] As a further improvement of the present invention, after the protective sleeve is installed, the top end of the protective sleeve is located above the ground, and the distance between it and the ground is 0.1 to 0.3 m; the bottom end of the protective sleeve is located below the groundwater level, and the distance between it and the groundwater level is 0.2 to 0.5 m.

[0012] 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 groove for connecting to the drilling body, and the other end is provided with a first threaded boss adapted to the first threaded groove; the inlet of the first gas transmission channel is located on the end face of the first threaded boss, and the outlet is located on the bottom face of the first threaded groove; the drilling body includes a conical hollow drill bit, one end of the conical hollow drill bit is provided with a second threaded boss adapted to the first threaded groove; the inlet of the third gas transmission channel is located on the end face of the second threaded boss, and the outlet is located on the inner wall surface of the conical hollow drill bit.

[0013] As a further improvement of the present invention, in step 10, a spiral drill rod is used to drill to form a pre-formed hole.

[0014] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: The sampling and storage method for maintaining the redox state of the in-situ strata of the soil provided by the present invention first drills to the depth of the groundwater to form a pre-formed hole above the groundwater level; then installs a protective casing in the pre-formed hole, and introduces an inert gas into the protective casing; finally, uses a high-fidelity sampling drill to collect soil samples below the groundwater level. When sampling, the drilling body, multiple first drill rods, and the propulsion body are connected in sequence from bottom to top, and the sampling tube filled with inert gas is installed in the first drill rod at the bottom. The inert gas is introduced from the inlet of the second gas transmission channel of the propulsion body. The inert gas enters the sampling cavity through the second gas transmission channel of the propulsion body, the first gas transmission channel of the first drill rod, and the third gas transmission channel of the drilling body in sequence, so that the sampling cavity is filled with inert gas, so that the soil below the drilling body is isolated from the atmosphere; the drilling rig presses down on the propulsion body, pushing the drilling body and the first drill rod to gradually Moving downward, the soil sample enters the sampling tube, and the soil sample in the sampling tube never contacts the atmosphere; after the sampling tube is full, a new sampling tube is replaced, and inert gas is introduced again from the inlet of the second gas transmission channel of the propulsion body, and the inert gas enters the sampling cavity through the second gas transmission channel of the propulsion body, the first gas transmission channel of the first drill rod, and the third gas transmission channel of the drilling body in turn, so that the sampling cavity is filled with inert gas, so that the soil under the drilling body is isolated from the atmosphere; then press down to take samples, and the soil sample in the sampling tube never contacts the atmosphere. When pulling out the sampling tube, after the bottom end of the sampling tube reaches the buffer cavity of the propulsion body, the bottom end of the sampling tube is pressed into the sealing sleeve, and the bottom end of the sampling tube is sealed with the sealing sleeve, so that after the sampling tube leaves the sampling cavity, the soil sample in the sampling tube is always isolated from the atmosphere. By installing the first drill rod and continuously increasing the downward pressure depth, soil samples within the predetermined depth range are collected. During the collection process, the soil below the drilling body is always effectively isolated from the atmosphere, and the redox potential of the soil in the saturated zone below the groundwater level is maintained, so as to achieve high-fidelity collection of soil samples. After obtaining the soil samples, the temperature of each section of the soil sample in the stratum is collected in real time at the depth position, and each section of the soil sample is placed in the corresponding temperature environment for storage, so as to achieve high-fidelity storage of the soil samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a flow chart of a method according to an embodiment of the present invention; Figure 2 is a cross-sectional view of a first drill rod of a high-fidelity sampling drill tool in an embodiment of the method of the present invention; Figure 3 is a cross-sectional view of a drilling body of a high-fidelity sampling drill in an embodiment of the present invention; Figure 4 is a cross-sectional view of a propulsion body of a high-fidelity sampling drill in an embodiment of the present invention; Figure 5 is a top view of the main body of the propulsion body of the high-fidelity sampling drill in the embodiment method of the present invention; Figure 6 is a top view of a sealing plate in a propulsion body of a high-fidelity sampling drill in an embodiment of the present invention when the sealing plate is closed; Figure 7 is a cross-sectional view of a sampling tube of a high-fidelity sampling drill in an embodiment of the present invention; Figure 8 It is a stratigraphic cross-sectional view of the temperature at the depth of each soil sample in the stratigraphic layer after the sampling is completed in the method of the embodiment of the present invention; Fig. 9 It is a schematic diagram of the structure of the temperature acquisition device in the method of the embodiment of the present invention; Fig.10 It is a schematic diagram of the structure of a sample storage box in the method of an embodiment of the present invention.

[0016] In the figure: a first hollow rod body 10, a first gas transmission channel 11, a second gas guide groove 12, a third gas guide groove 13, a second sealing ring 14, a third sealing ring 15, a main body 20, a second gas transmission channel 21, a sealing plate 22, a cover body 23, a fourth gas guide groove 24, a fourth sealing ring 25, an upper opening 26, a rotating shaft 27, a sealing sleeve 28, a conical hollow drill bit 30, a third gas transmission channel 31, a first gas guide groove 32, a first sealing ring 33, a sampling tube 4, a hollow tube body 41, a top plug 42, a piston 43, an inflation plug 44, a push rod 5, a protective sleeve 6, a second gas transmission channel 61, a groundwater level 7, a ground 8, a bracket 91, a temperature sensor 92, a collection terminal 93, a temperature control terminal 94, a storage grid 95, and a soil sample 96. DETAILED DESCRIPTION

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

[0018] The embodiment of the present invention provides a sampling and storage method for maintaining the redox state of the in-situ stratum of soil, using a high-fidelity sampling drill. The high-fidelity sampling drill includes a drilling body, a first drill rod, a propulsion body and a sampling tube, and the drilling body, the first drill rod and the propulsion body all have an inner cavity. The drilling body is provided with a third gas transmission channel 31 connected to its inner cavity, the first drill rod is provided with a first gas transmission channel 11, and the propulsion body is provided with a second gas transmission channel 21. Among them, the number of first drill rods is determined according to the field collection depth. When in use, the drilling body, N first drill rods and the propulsion body are connected in sequence from bottom to top, and the inner cavities of the drilling body, N first drill rods and the propulsion body are connected in sequence to form a sampling cavity, and the second gas transmission channel 21, the first gas transmission channel 11, the third gas transmission channel 31 and the sampling cavity are connected in sequence. N is an integer greater than or equal to 1. The sampling tube is installed in the inner cavity of the first drill rod at the bottom. The high-fidelity sampling drill tool of the embodiment of the present invention further includes a mandrel 5, which is installed at the top of the sampling tube for sampling, and the number of mandrels is determined according to the field sampling depth. Preferably, the length of the sampling tube, the length of the first drill rod, and the length of the mandrel are all equal, and the difference between the number of the first drill rods and the number of the mandrels is 1.

[0019] like Figure 3 As shown, the drilling body includes a conical hollow drill bit 30, and one end of the conical hollow drill bit 30 is provided with a second threaded boss for connecting to the first drill rod. The inlet of the third gas transmission channel 31 is located on the end face of the second threaded boss, and the outlet is located on the inner wall surface of the conical hollow drill bit 30. Preferably, a half circle of first air guide grooves 32 are provided on the end face of the second threaded boss along the circumference of the inner cavity, and the first air guide grooves 32 are connected to the inlet of the third gas transmission channel 31. Two circles of first sealing rings 33 are also provided on the end face of the second threaded boss, and the inlet of the third gas transmission channel 31 is located between the two circles of first sealing rings 33.

[0020] like Figure 2 As shown, the first drill rod includes a first hollow rod body 10, one end (bottom end) of the first hollow rod body 10 is provided with a first thread groove for connecting with the drilling body, and the first thread groove is adapted to the second thread convex head. The other end (top end) is provided with a first thread convex head adapted to the first thread groove, so that multiple first hollow rod bodies 10 can be connected in sequence. The inlet of the first gas transmission channel 11 is located on the end surface of the first thread convex head, and the outlet is located on the bottom surface of the groove of the first thread groove.

[0021] Preferably, a half circle of second air guide groove 12 is provided on the end surface of the first threaded protrusion along the circumference of the inner cavity, and the second air guide groove 12 is connected to the inlet of the first gas transmission channel 11. A half circle of third air guide groove 13 is provided on the groove bottom surface of the first threaded groove along the circumference of the inner cavity, and the third air guide groove 13 is connected to the outlet of the first gas transmission channel 11. When the first drill rod is connected to the drilling body, the first air guide groove 32 is connected to the third air guide groove 13 correspondingly, the first gas transmission channel 11 of the first drill rod is connected to the third air guide groove 13, and the third gas transmission channel 31 of the drilling body is connected to the first air guide groove 32, so that even if the outlet of the first gas transmission channel 11 is not opposite to the inlet of the third gas transmission channel, the first gas transmission channel and the third gas transmission channel can be connected, and the inert gas can be well transmitted. When two adjacent first drill rods are connected, the second gas guide groove 12 is connected to the third gas guide groove 13 correspondingly, the first gas transmission channel 11 of the upper first drill rod is connected to the third gas guide groove 13, and the first gas transmission channel 11 of the lower first drill rod is connected to the second gas transmission groove 12. Therefore, even if the outlet and the inlet of the first gas transmission channel of the two adjacent first drill rods are not opposite to each other, the two first gas transmission channels can be connected, so that the inert gas can be well transmitted.

[0022] Preferably, two circles of second sealing rings 14 are provided on the end surface of the first threaded boss, and the inlet of the first gas transmission channel is located between the two circles of second sealing rings 14. Two circles of third sealing rings 15 are provided on the bottom surface of the first threaded groove, and the outlet of the first gas transmission channel is located between the two circles of third sealing rings 15. After the first drill rod is connected to the drilling body, the two circles of third sealing rings 15 cooperate with the two circles of first sealing rings 33, and after the adjacent first drill rods are connected, the two circles of second sealing rings 14 cooperate with the two circles of third sealing rings 15 to prevent the leakage of inert gas at the connection between the threaded boss or the threaded groove, which causes the inert gas flow at the gas outlet of the drilling body to be small or even no gas is discharged, thereby failing to achieve the expected effect of removing the air in the sampling chamber.

[0023] like Figure 4As shown, the propulsion body includes a main body 20 having a buffer cavity and a cover body 23, and the cover body 23 is movably connected to the upper end of the main body. The upper and lower ends of the main body have openings, and the end surface of the cover body 23 is provided with a protrusion for inserting into the upper end opening of the main body 20. The second gas transmission channel 21 is arranged on the side wall of the main body 20. A second threaded groove for connecting with the first drill rod is provided at the lower end opening of the main body, and the second threaded groove is adapted to the first threaded protrusion of the first drill rod. The inlet of the second gas transmission channel 21 is located on the side wall surface of the main body, and the outlet is located on the groove bottom surface of the second threaded groove. Preferably, a half-circle fourth air guide groove 24 is provided on the groove bottom surface of the second threaded groove, and the fourth air guide groove 24 is connected to the outlet of the second gas transmission channel 21. When the propulsion body is connected to the first drill rod, the fourth gas guide groove 24 is connected to the second gas guide groove 12, the first gas transmission channel 11 of the first drill rod is connected to the second gas transmission channel 12, and the second gas transmission channel 21 of the propulsion body is connected to the fourth gas guide groove 24. Therefore, even if the inlet of the first gas transmission channel is not opposite to the outlet of the propulsion body, the first gas transmission channel and the second gas transmission channel can be connected, and the inert gas can be well transmitted. Two circles of fourth sealing rings 25 are also provided on the bottom surface of the second threaded groove, and the outlet of the second gas transmission channel is located between the two circles of fourth sealing rings. After the first drill rod is connected to the propulsion body, the two circles of fourth sealing rings cooperate with the two circles of second sealing rings to prevent the inert gas from leaking at the connection between the threaded boss or the threaded groove.

[0024] The upper opening 26 of the body is an elliptical hole, such as Figure 5 As shown. A sealing plate 22 is also provided at the upper opening of the body, and the sealing plate 22 is connected to the upper end surface of the body 20 through a rotating shaft 27. The sealing plate 22 rotates to switch between an open state and a closed state. When the sealing plate is opened, the sealing plate is away from the upper opening, and when the sealing plate is closed, Figure 6 As shown, part of the upper opening can be covered so that the upper opening is reduced to fit with the protrusion of the cover body 23.

[0025] A limiting hole is provided in the buffer cavity of the body 20, and the limiting hole is used to install the sealing sleeve 28 with an open top and a closed bottom. The side wall of the sealing sleeve 28 is provided with a gas delivery port that is connected to the inner cavity of the sealing sleeve and extends obliquely downward from the outer wall of the sealing sleeve to the inner wall of the sealing sleeve. A branch pipe is provided on the second gas delivery channel 21. When the sealing sleeve is installed in the limiting hole, the outlet of the branch pipe is connected to the gas delivery port, and inert gas can be input into the sleeve through the branch pipe and the gas delivery port.

[0026] When in use, the propulsion body is installed at the top of the first drill rod at the top, the cover body is removed, and the sealing plate is opened. After the sampling tube is loaded, the sealing tube sleeve is installed in the buffer cavity of the propulsion body, the sealing plate is closed, and inert gas is introduced from the inlet of the second gas transmission channel of the propulsion body. The inert gas enters the sampling cavity and also enters the inner cavity of the sealing tube sleeve until the sampling cavity is filled with inert gas. At this time, the inner cavity of the sealing tube sleeve is also filled with inert gas. Install the cover body. Press down the propulsion body, the first drill rod moves downward, and the soil sample enters the sampling tube. When the first drill rod at the top is completely pressed into the formation, the sampling tube is filled with soil samples. Remove the cover body, lift the sampling tube filled with soil samples upward, and when the bottom end of the sampling tube reaches the buffer cavity of the propulsion body, open the sealing plate, move the bottom end of the sampling tube to the top of the sealing tube sleeve, and press the bottom end of the sampling tube into the sealing tube sleeve, so that the bottom end of the sampling tube is sealed by the sealing tube sleeve, take out the sampling tube with the sealing tube sleeve, and number it.

[0027] The propulsion body in this embodiment is provided with a sealing sleeve in the buffer cavity. Before the sampling tube is pulled out of the sampling cavity, the bottom end of the sampling tube is sealed by the sealing sleeve, so that after the sampling tube leaves the sampling cavity, the soil sample in the sampling tube is always isolated from the atmosphere. A sealing plate is provided at the upper opening of the body, and inert gas is input into the sampling cavity while inert gas is also input into the sealing sleeve. By controlling the opening and closing state of the sealing plate, the buffer cavity can be isolated from the outside atmosphere, so that the bottom end of the sampling tube is located in an inert gas environment before the sealing sleeve is installed; the sealing plate can provide convenience for installing the sealing sleeve at the bottom end of the sampling tube, further ensuring the contact between the soil sample and the atmosphere during the sampling process; at the same time, the sealing plate cooperates with the detachable cover body to ensure the high-quality completion of the operation processes such as emptying the air in the sampling cavity and taking out the sampling tube, and significantly improve the sampling efficiency.

[0028] like Figure 7 As shown, the sampling tube includes a hollow tube body 41, a top plug 42 is fixedly installed at the top of the hollow tube body 41, a first air guide channel is provided on the top plug 42, one end of the first air guide channel is connected to the inner cavity of the hollow tube body 41, and the other end is provided with a first one-way valve. A piston 43 is provided in the hollow tube body. An inflation plug 44 is detachably installed at the bottom end of the hollow tube body, a second air guide channel is provided on the inflation plug, a second one-way valve is provided at one end of the second air guide channel, and a gas guide needle is provided at the other end. When the inflation plug 44 is installed at the bottom end of the hollow tube body, the gas guide needle passes through the piston 43 and is connected to the inner cavity of the hollow tube body 41.

[0029] Before the sampling tube is loaded into the sampling cavity, an air-filling plug 44 is installed at the bottom of the hollow tube body, and the air-guiding needle passes through the piston 43 to communicate with the inner cavity of the hollow tube body 41. Inert gas is input from the inlet of the second air-guiding channel, and the inert gas enters the inner cavity of the hollow tube body 41 through the air-guiding needle. The air in the hollow tube body 41 moves upward and is discharged through the first air-guiding channel. When the hollow tube body is filled with inert gas, the air-filling plug 44 is removed, so that the piston 43 closes the bottom end of the hollow tube body to prevent air from entering the hollow tube body, and ensure that the hollow tube body is effectively filled with inert gas before sampling.

[0030] The high-fidelity sampling drill tool in the embodiment of the present invention adopts a first drill rod to fix and protect the sampling tube, so that the sampling tube will not be deformed or damaged 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 is prone to deformation or damage during use. In order to facilitate quick replacement, the upper end of the conical hollow drill bit is set in the form of a threaded boss, and the first drill rod is connected to the drilling body by inserting it into the threaded groove of the first drill rod. In addition, the part of the first drill rod that bears the largest impact load is the top part connected to the propulsion body. Therefore, the top part of the first drill rod is designed to be in the form of a threaded boss. Compared with the use of a threaded groove, it can effectively avoid the situation where the propulsion body cannot be removed after being damaged because it is embedded in the top of the first drill rod, thereby reducing the equipment maintenance cost during the sampling process.

[0031] The embodiment of the present invention provides a sampling and storage method for maintaining the redox state of the soil in situ strata, such as Figure 1 As shown, the following steps are included: Step 10, drilling to the groundwater burial depth to form a pre-formed hole above the groundwater level.

[0032] Since there are various types of microorganisms in the soil near the depth of groundwater, including both aerobic and anaerobic microbial communities, the microbial community structure is complex. Before collecting soil samples below the groundwater level, pre-drilling holes above the groundwater level can avoid the compression of the strata within the depth range during the collection process of shallow unsaturated soil, causing changes in the soil pore structure, and further affecting the redox state of the collected soil samples.

[0033] Preferably, the diameter of the pre-formed hole is 5 to 10 times the diameter of the preset sampling soil core. By reasonably designing the diameter of the pre-formed hole, the compression effect of the soil collection process on the strata within the depth range can be effectively avoided, while reducing the stress release and deformation of the soil layer near the groundwater burial depth caused by the pre-formed hole excavation, and maintaining the original state of the in-situ strata. If the diameter of the pre-formed hole is too small, the stratum stress adjustment will be insufficient during the pre-formed hole process; if the diameter is too large, the sampling efficiency will be reduced.

[0034] There are many schemes for drilling to form a pre-formed hole. The first scheme is to use an existing spiral drill rod to drill to form a pre-formed hole.

[0035] The second option is to use high-fidelity sampling drill tools to drill and form pre-formed holes.

[0036] Specifically include: Step 101, install the first first drill rod at the top of the drilling body, install the first sampling tube into the first drill rod, and then install the propulsion body at the top of the first first drill rod. Press the propulsion body downward, the first first drill rod moves downward, and soil enters the first sampling tube. When the first first drill rod is completely pressed into the formation, the first sampling tube is filled with soil. Separate the propulsion body from the first first drill rod, and take out the first sampling tube filled with soil.

[0037] Step 102, install the second first drill rod on the top of the first first drill rod, install the second sampling tube installed with a push rod into the first drill rod at the bottom, and then install the propulsion body on the top of the second first drill rod. Press the propulsion body downward, the second first drill rod moves downward, and the soil enters the second sampling tube. When the second second drill rod is completely pressed into the formation, the second sampling tube is filled with soil. Separate the propulsion body from the second first drill rod, and take out the second sampling tube filled with soil.

[0038] Step 103, adding first drill rods in sequence, replacing a sampling tube each time a first drill rod is added, until the bottom end of the drilling body is located at the groundwater burial depth.

[0039] Step 104, taking out the high-fidelity sampling drill from the formation to form a pre-drilled hole.

[0040] Step 20, such as Figure 8 As shown, the protective sleeve 6 is installed in the pre-formed hole. A fourth gas transmission channel 61 is provided on the protective sleeve 6, the inlet of the fourth gas transmission channel 61 is located on the top outer wall surface of the protective sleeve, and the outlet is located on the bottom inner wall surface. Bentonite slurry is filled between the outer side of the protective sleeve and the pre-formed hole to prevent the protective sleeve from shaking in the soil layer and causing the air-locking effect to be weakened.

[0041] Preferably, the diameter of the protective sleeve 6 is equal to the theoretical construction diameter of the preformed hole.

[0042] Preferably, after the protective sleeve 6 is installed, the top of the protective sleeve 6 is located above the ground 8, and the distance between the top of the protective sleeve 6 and the ground 8 is 0.1 to 0.3 m. The top of the protective sleeve is higher than the ground, which can effectively prevent the soil around the sampling point from falling into the pre-formed hole, thereby contaminating the soil of the in-situ formation. In addition, maintaining a distance between the top of the protective sleeve and the ground 8 can provide sufficient operating space for the inlet design of the fourth gas transmission channel 61 and the subsequent introduction of inert gas.

[0043] The bottom end of the protective sleeve 6 is located below the groundwater level 7, and the distance between the protective sleeve and the groundwater level 7 is 0.2-0.5 m. The bottom end of the protective sleeve is embedded a certain distance below the groundwater level, which can effectively avoid significant changes in the soil pore structure during the soil collection process near the groundwater burial depth and maintain the redox state of the collected soil sample.

[0044] Inert gas is introduced from the inlet of the fourth gas transmission channel of the protective sleeve until the inner cavity of the protective sleeve is filled with inert gas. The protective sleeve is filled with inert gas to prevent the soil near the groundwater burial depth from contacting the atmosphere and maintain the redox state of the soil near the groundwater burial depth.

[0045] Step 30, using a high-fidelity sampling drill to drill through the protective casing downward to obtain soil samples within a predetermined depth range below the groundwater level.

[0046] Specifically include: Step 301, insert the drilling body into the protective casing from the top of the protective casing, and sequentially install the first, second, ..., nth first drill rods on the top of the drilling body until the bottom of the drilling body reaches the groundwater burial depth and the bottom of the nth first drill rod is near the ground. n is an integer greater than or equal to 1.

[0047] Step 302: Install the propulsion body at the top of the nth first drill rod, remove the cover, and open the sealing plate. Install the first sampling tube with n-1 push rods installed into the sampling cavity, so that the first sampling tube is located in the inner cavity of the lowest first drill rod.

[0048] Step 303, install the first sealing tube sleeve into the buffer cavity of the propulsion body, close the sealing plate, introduce inert gas from the inlet of the second gas delivery channel of the propulsion body until the sampling cavity and the inner cavity of the sealing tube sleeve are filled with inert gas, and install the cover body.

[0049] Step 304: Press down the propulsion body, the n first drill rods move downward, and the soil sample enters the first sampling tube. When the nth first drill rod is completely pressed into the formation, the first sampling tube is filled with the soil sample.

[0050] Step 305, remove the cover body, lift the sampling tube filled with soil sample upward, and when the bottom end of the sampling tube reaches the buffer cavity of the propulsion body, open the sealing plate. Move the bottom end of the sampling tube to the top of the sealing sleeve, and press the bottom end of the sampling tube into the sealing sleeve, and the bottom end of the sampling tube is sealed by the sealing sleeve. Take out the sampling tube with the sealing sleeve, number it, and obtain the first section of soil sample below the groundwater level.

[0051] Step 306: Separate the propulsion body from the nth first drill rod, and install the n+1th first drill rod on the top of the nth first drill rod. The value of p is 1.

[0052] Step 307, install the propulsion body at the top of the n+pth first drill rod, remove the cover, and open the sealing plate. Install the p+1th sampling tube with the n+p-1th push rod installed into the sampling cavity, so that the p+1th sampling tube is located in the inner cavity of the first drill rod at the bottom.

[0053] Step 308, install the p+1th sealing tube sleeve into the buffer cavity of the propulsion body, close the sealing plate, introduce inert gas from the inlet of the second gas delivery channel of the propulsion body until the sampling cavity and the inner cavity of the sealing tube sleeve are filled with inert gas, and install the cover body.

[0054] Step 309, press down the propulsion body, the n+p first drill rods move downward, and the soil sample enters the p+1th sampling tube. When the n+pth first drill rods are all pressed into the formation, the p+1th sampling tube is filled with soil samples.

[0055] Step 310, remove the cover, lift the sampling tube filled with soil sample upward, and when the bottom end of the sampling tube reaches the buffer cavity of the propulsion body, open the sealing plate. Move the bottom end of the sampling tube to the top of the sealing sleeve, and press the bottom end of the sampling tube into the sealing sleeve, take out the sampling tube with the sealing sleeve, and number it to obtain the p+1th section of soil sample below the groundwater level. The value of p increases by 1.

[0056] Step 311, repeating steps 307 to 310 until soil samples within a predetermined depth range are taken out.

[0057] Step 40, using Fig. 9 The temperature collection device shown collects the temperature of each soil sample at a depth in the stratum in real time, and stores each soil sample in a corresponding temperature environment.

[0058] Specifically include: The middle of each soil sample at the depth of the original stratum is selected as the temperature measuring point corresponding to each soil sample. Temperature sensors 92 are installed on the bracket 91 according to the distribution of each temperature measuring point, and each temperature measuring point corresponds to a temperature sensor.

[0059] like Figure 8 As shown, the bracket 91 is installed in the sampling cavity, and the bottom end of the bracket 91 is inserted into the soil to a preset depth, so that each temperature sensor is located at a depth position in the middle of each soil sample in the original stratum.

[0060] The high-fidelity sampling drill and the protective casing are pulled out, and the support 91 is buried in the soil layer to seal the pre-formed hole.

[0061] All temperature sensors are buried in the soil layer to monitor the temperature of each section of soil samples in the original stratum for a long time, and the storage temperature of each section of soil samples is adjusted according to the real-time temperature in the stratum.

[0062] Specifically, after the collection is completed, all numbered sampling tubes are placed in a sample storage box for storage. Fig.10 As shown, the sample storage box includes a box body and a temperature control terminal 94. The box body is provided with mutually isolated storage cells 95. Each storage cell 95 is used to place a sampling tube 4 with a soil sample 96. Each storage cell 95 is provided with a temperature controller for controlling the temperature in the storage cell. The temperature controller is connected to the temperature control terminal 94.

[0063] After the bracket 91 with the temperature sensor is buried in the soil layer, the acquisition terminal 93 collects the temperature data of different depths in the stratum detected by all temperature sensors, and sends the temperature data to the temperature control terminal 94 of the sample storage box. The temperature control terminal sends the temperature data of different depths to the temperature controller of the storage grid storing the soil samples of the corresponding depth. Each temperature controller controls the temperature of the storage grid where it is located to the temperature of the corresponding depth, so that the storage temperature of each soil sample is the real-time temperature of each depth in the original soil layer.

[0064] The sampling and storage method for maintaining the redox state of the in-situ strata of the soil provided by the present invention first drills to the depth of the groundwater to form a pre-formed hole above the groundwater level; then installs a protective casing in the pre-formed hole, and introduces an inert gas into the protective casing; finally, uses a high-fidelity sampling drill to collect soil samples below the groundwater level. When sampling, the drilling body, multiple first drill rods, and the propulsion body are connected in sequence from bottom to top, and the sampling tube filled with inert gas is installed in the first drill rod at the bottom. The inert gas is introduced from the inlet of the second gas transmission channel of the propulsion body. The inert gas enters the sampling cavity through the second gas transmission channel of the propulsion body, the first gas transmission channel of the first drill rod, and the third gas transmission channel of the drilling body in sequence, so that the sampling cavity is filled with inert gas, so that the soil below the drilling body is isolated from the atmosphere; the drilling rig presses down on the propulsion body, pushing the drilling body and the first drill rod to gradually Moving downward, the soil sample enters the sampling tube, and the soil sample in the sampling tube never contacts the atmosphere; after the sampling tube is full, a new sampling tube is replaced, and inert gas is introduced again from the inlet of the second gas transmission channel of the propulsion body, and the inert gas enters the sampling cavity through the second gas transmission channel of the propulsion body, the first gas transmission channel of the first drill rod, and the third gas transmission channel of the drilling body in turn, so that the sampling cavity is filled with inert gas, so that the soil under the drilling body is isolated from the atmosphere; then press down to take samples, and the soil sample in the sampling tube never contacts the atmosphere. When pulling out the sampling tube, after the bottom end of the sampling tube reaches the buffer cavity of the propulsion body, the bottom end of the sampling tube is pressed into the sealing sleeve, and the bottom end of the sampling tube is sealed with the sealing sleeve, so that after the sampling tube leaves the sampling cavity, the soil sample in the sampling tube is always isolated from the atmosphere. By adding the first drill rod and continuously increasing the downward pressure depth, soil samples within the predetermined depth range are collected. During the collection process, the soil below the drilling body is always effectively isolated from the atmosphere, and the redox potential of the soil in the saturated zone below the groundwater level is maintained, so as to achieve high-fidelity collection of soil samples. After obtaining the soil samples, the temperature of each section of the soil sample in the stratum is collected in real time at the depth position, and each section of the soil sample is placed in the corresponding temperature environment for storage, so as to achieve high-fidelity storage of the soil samples.

[0065] 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 and storage method for maintaining the redox state of soil in situ strata, characterized in that: The following steps are involved: Step 10, drilling to the groundwater depth, forming a pre-formed hole above the groundwater level; Step 20, installing the protective sleeve into the pre-formed hole, and introducing an inert gas into the protective sleeve until the inner cavity of the protective sleeve is filled with the inert gas; Step 30, using a high-fidelity sampling drill to collect soil samples within a predetermined depth range below the groundwater level through the protective casing; Step 40, collecting the temperature of each soil sample at the depth in the stratum in real time, and storing each soil sample in a corresponding temperature environment.

2. The method for sampling and storing soil to maintain the redox state of the in-situ strata according to claim 1, characterized in that: The high-fidelity sampling drill comprises a drilling body, a first drill rod, a propulsion body and a sampling tube, wherein the drilling body, the first drill rod and the propulsion body all have inner cavities; the drilling body is provided with a third gas transmission channel (31) connected to its inner cavity, the first drill rod is provided with a first gas transmission channel (11), and the propulsion body is provided with a second gas transmission channel (21); when in use, the drilling body, N first drill rods and the propulsion body are sequentially connected from bottom to top, the drilling body, the N first drill rods and the inner cavities of the propulsion body are sequentially connected to form a sampling cavity, and the second gas transmission channel (21), the first gas transmission channel (11), the third gas transmission channel (31) and the sampling cavity are sequentially connected; the sampling tube is installed in the inner cavity of the first drill rod at the bottom; N is an integer greater than or equal to 1.

3. The method for sampling and storing soil to maintain the redox state of the in-situ strata according to claim 2, characterized in that: The propulsion body comprises a body (20) having a buffer cavity and a cover body (23), wherein the cover body (23) is movably connected to the upper end of the body (20); the second gas delivery channel (21) is arranged on the side wall of the body (20); the upper and lower ends of the body (20) both have openings, and a sealing plate (22) is arranged at the upper opening of the body; a limiting hole for accommodating a sealing sleeve (28) having an open top and a closed bottom is arranged in the buffer cavity, and a gas delivery port is arranged on the side wall of the sealing sleeve (28) which is in communication with the second gas delivery channel (21) and extends downwardly from the outside to the inside in an inclined manner.

4. The method for sampling and storing soil to maintain the redox state of the in-situ strata according to claim 3, characterized in that: The step 30 specifically includes: Step 301, insert the drilling body into the protective casing from the top of the protective casing, and sequentially install the first, second, ..., nth first drill rods on the top of the drilling body until the bottom end of the drilling body reaches the groundwater burial depth and the bottom end of the nth first drill rod is located near the ground; n is an integer greater than or equal to 1; Step 302, install the propulsion body at the top of the nth first drill rod, remove the cover body, and open the sealing plate; install the first sampling tube installed with n-1 push rods from the upper end opening of the body, so that the first sampling tube is located in the inner cavity of the first drill rod at the bottom; Step 303, install the first sealing tube sleeve into the buffer cavity of the propulsion body, close the sealing plate; introduce inert gas from the inlet of the second gas transmission channel of the propulsion body until the sampling cavity is filled with inert gas; install the cover body; Step 304, the propulsion body is pushed down, the n first drill rods move downward, and the soil sample enters the first sampling tube; when the Nth first drill rod is completely pressed into the formation, the first sampling tube is filled with the soil sample; Step 305, remove the cover body, lift the sampling tube filled with soil sample upward, when the bottom end of the sampling tube reaches the buffer cavity of the propulsion body, open the sealing plate, move the bottom end of the sampling tube to the top of the sealing tube sleeve, and press the bottom end of the sampling tube into the sealing tube sleeve; take out the sampling tube with the air duct sleeve, number it, and obtain the first section of soil sample below the groundwater level; Step 306, separate the propulsion body from the nth first drill rod, and install the n+1th first drill rod on the top of the nth first drill rod; p=1; Step 307, install a propulsion body at the top of the n+pth first drill rod; remove the cover body and open the sealing plate; install the p+1th sampling tube installed with the n+p-1th push rod from the upper end opening of the body, so that the p+1th sampling tube is located in the inner cavity of the first drill rod at the bottom; Step 308, install the p+1th sealing tube sleeve into the buffer cavity of the propulsion body, close the sealing plate; introduce inert gas from the inlet of the second gas transmission channel of the propulsion body until the sampling cavity is filled with inert gas; install the cover body; Step 309, the propulsion body is pushed down, the n+p first drill rods move downward, and the soil sample enters the p+1th sampling tube; when the n+pth first drill rods are all pressed into the formation, the p+1th sampling tube is filled with soil samples; Step 310, remove the cover body, lift the sampling tube filled with soil sample upward, when the bottom end of the sampling tube reaches the buffer cavity of the propulsion body, open the sealing plate, move the bottom end of the sampling tube to the top of the sealing sleeve, and press the bottom end of the sampling tube into the sealing sleeve; take out the sampling tube with the sealing sleeve, number it, and obtain the p+1th section of soil sample below the groundwater level; the value of p increases by 1; Step 311, repeating steps 307 to 310 until soil samples within a predetermined depth range are taken out.

5. The method for sampling and storing soil to maintain the redox state of the in-situ strata according to claim 1, characterized in that: The step 40 specifically includes: The middle of each soil sample at the depth of the original stratum is selected as the temperature measuring point corresponding to each soil sample, and temperature sensors are installed on the bracket according to the distribution of each temperature measuring point, and each temperature measuring point corresponds to a temperature sensor; The bracket is placed in the sampling cavity of the high-fidelity sampling drill, and the bottom end of the bracket is embedded in the soil at a preset depth, so that each temperature sensor is located at the depth position of the middle of each soil sample in the original formation; Pull out the high-fidelity sampling drill and protective casing, bury the bracket in the soil layer, and seal the pre-drilled hole; The temperature of each section of soil sample in the original stratum is measured by a temperature sensor, and each section of soil sample is placed in a corresponding temperature environment for storage; according to the measurement data of the temperature sensor, the storage temperature of each section of soil sample is adjusted in real time.

6. The method for sampling and storing soil to maintain the redox state of the in-situ strata according to claim 1, characterized in that: Before the sampling tube is installed into the first drill pipe, an inert gas is first introduced into the sampling tube until the sampling tube is filled with the inert gas.

7. The method for sampling and storing soil to maintain the redox state of the in-situ strata according to claim 1, characterized in that: The sampling tube comprises a hollow tube body (41), a top plug (42) is fixedly mounted on the top end of the hollow tube body (41), a first air guide channel is provided on the top plug, one end of the first air guide channel is in communication with the inner cavity of the hollow tube body (41), and the other end is provided with a first one-way valve; a piston (43) is provided in the hollow tube body; an inflation plug (44) is detachably mounted on the bottom end of the hollow tube body, a second air guide channel is provided on the inflation plug, one end of the second air guide channel is provided with a second one-way valve, and the other end is provided with an air guide needle; when the inflation plug (44) is mounted on the bottom end of the hollow tube body, the air guide needle passes through the piston (43) and is in communication with the inner cavity of the hollow tube body (41).

8. The method for sampling and storing soil to maintain the redox state of the in-situ strata according to claim 1, characterized in that: After the protective sleeve is installed, the top end of the protective sleeve (6) is located above the ground and the distance between the top end and the ground is 0.1 to 0.3 m; the bottom end of the protective sleeve (6) is located below the groundwater level and the distance between the bottom end and the groundwater level is 0.2 to 0.5 m.

9. The method for sampling and storing soil to maintain the redox state of the in-situ strata according to claim 1, characterized in that: The first drill rod comprises a first hollow rod body (10), one end of the first hollow rod body (10) is provided with a first threaded groove for connecting to a drilling body, and the other end is provided with a first threaded protrusion adapted to the first threaded groove; the inlet of the first gas transmission channel (11) is located on the end surface of the first threaded protrusion, and the outlet is located on the groove bottom surface of the first threaded groove; the drilling body comprises a conical hollow drill bit (30), one end of the conical hollow drill bit (30) is provided with a second threaded protrusion adapted to the first threaded groove; the inlet of the third gas transmission channel (31) is located on the end surface of the second threaded protrusion, and the outlet is located on the inner wall surface of the conical hollow drill bit (30).

10. The method for sampling and storing soil to maintain the redox state of the in-situ strata according to claim 1, characterized in that: In step 10, a spiral drill rod is used to drill to form a pre-formed hole.

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