Soil high-fidelity acquisition method based on pore water electrolysis resistance reduction

Abstract

The invention provides a high-fidelity soil acquisition method based on pore water electrolysis resistance reduction, which comprises the following steps: step 10, drilling to an underground water level position at a sampling point to form a preformed hole; step 20, inserting a plurality of electrode plates around the sampling point; penetrating a sampling drill rod from the preformed hole, connecting the sampling drill rod with a negative electrode of an adjustable power supply, and connecting an electrode plate with a positive electrode of the adjustable power supply; in the process that the traction unit drives the sampling drill rod to penetrate into the position below the underground water level, the electrode plate and the sampling drill rod are powered on, interstitial water in the soil body near the sampling drill rod is electrolyzed, and bubbles are generated; meanwhile, the vertical vibration unit drives the sampling drill rod to vibrate in a reciprocating manner in the vertical direction, and the soil body near the sampling drill rod is induced to be liquefied until the soil sample in the preset sampling depth range is taken out. According to the high-fidelity soil collection method based on pore water electrolysis resistance reduction, disturbance is reduced, the soil structure is prevented from being obviously changed, and the fidelity effect of the soil sample is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil drilling and sampling, and specifically relates to a method for high-fidelity soil collection based on pore water electrolysis and drag reduction. Background Art

[0002] Fidelity sampling of contaminated sites is the basis for green and low-carbon remediation and risk control of contaminated sites. Existing static pressure penetration soil sampling drills, sonic vibration soil sampling drills and methods for collecting soil samples often have large deformations, and the soil structure is significantly changed. Although the vibration function of the sampling drill can induce slight liquefaction of the soil layer in the saturated zone below the groundwater level, to a certain extent, the sampling efficiency and the original structure of the soil are improved. However, due to the small particle size and large cohesion between particles of cohesive soils such as silt and silty clay, it is difficult to achieve a good liquefaction state under vibration, and the collected samples are still not ideal. Therefore, it is urgent to improve the existing static pressure penetration soil sampling drills and sonic vibration soil sampling drills and soil sampling methods, reasonably control the structural state of the soil at the interface between the drill pipe and the soil layer, and effectively improve the sampling quality and efficiency of contaminated soil samples in cohesive soil layers. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: to provide a method for high-fidelity soil collection based on pore water electrolysis and drag reduction, which can reduce disturbance, prevent obvious change in the shape of soil samples, and improve the fidelity effect of soil samples when collecting soil samples below the groundwater level.

[0004] To solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides a method for high-fidelity soil collection based on pore water electrolysis and drag reduction, comprising the following steps: Step 10, drill to the groundwater level at the sampling point to form a pre-drilled hole; Step 20, insert a plurality of electrode plates around the sampling point, and the insertion depth of the electrode plates is the same as the preset sampling depth; insert the sampling drill pipe into the pre-drilled hole, connect the sampling drill pipe to the negative pole of the adjustable power supply, and connect the electrode plates to the positive pole of the adjustable power supply; during the process of the traction unit driving the sampling drill pipe to penetrate downward below the groundwater level to collect soil samples, the electrode plates and the sampling drill pipe are energized to electrolyze the pore water in the soil near the sampling drill pipe to generate bubbles; at the same time, the vertical vibration unit drives the sampling drill pipe to reciprocate vertically to induce liquefaction of the soil near the sampling drill pipe until the soil samples within the preset sampling depth range are taken out.

[0005] As a further improvement of the present invention, the amplitude of the vertical vibration unit is determined by formula (1): Formula (1) In the formula, represents the amplitude of the vertical vibration unit, with the unit of mm; represents the median particle size of the soil, with the unit of mm; represents the shape adjustment coefficient, with the value range of -1.50 to -0.70, dimensionless; I p represents the plasticity index of the soil, dimensionless; I p0 represents the reference plasticity index of the soil, with the value range of 4 to 7, dimensionless; β represents the activity adjustment coefficient, with the value range of 0.15 to 0.45, with the unit of mm.

[0006] As a further improvement of the present invention, in step 20, drilling parameters are collected in real time and transmitted to an adjustable power supply, and the adjustable power supply adjusts the output voltage in real time according to the drilling parameters; the drilling parameters include formation conductivity, formation temperature, the length of the sampling drill pipe below the groundwater depth, and the penetration speed value of the sampling drill pipe.

[0007] As a further improvement of the present invention, in step 20, the output voltage is determined by formula (2): Formula (2) In the formula, represents the output voltage, with the unit of v; represents the distance adjustment coefficient between the electrode plate and the sampling point plane, with the value range of 2.5 to 4.3, with the unit of m 3 ⋅mol⋅min⋅Ω⋅kg -1 ; represents the diameter of the sampling drill pipe, with the unit of cm; represents the median particle size of the soil, with the unit of mm; represents the penetration speed value of the sampling drill pipe, with the unit of m / min; represents the length of the sampling drill pipe below the groundwater depth, with the unit of m; represents the formation conductivity, with the unit of mS / cm; represents the ideal gas constant, with the value of 8.31, with the unit of J·mol -1 ·K -1 ; represents the formation temperature, with the unit of K.

[0008] As a further improvement of the present invention, both the formation conductivity and the formation temperature are collected by a temperature and resistivity in-situ acquisition device installed at the bottom end of the sampling drill pipe.

[0009] As a further improvement of the present invention, the length of the sampling drill pipe below the groundwater depth is collected by a depth sensor placed on the ground and with the movable end connected to a fixture.

[0010] As a further improvement of the present invention, a plurality of electrode plates are sequentially connected by wires, and one of the electrode plates is connected to the positive pole of an adjustable power supply.

[0011] As a further improvement of the present invention, a plurality of electrode plates are uniformly arranged around the sampling point.

[0012] As a further improvement of the present invention, the number of electrode plates is 4 to 8.

[0013] As a further improvement of the present invention, the step 20 specifically includes: Step 201, insert a plurality of electrode plates around the sampling point, the insertion depth of the electrode plates is consistent with the preset sampling depth, and connect the electrode plates to the positive pole of the adjustable power supply; Step 202, install the first rod body at the top end of the drill bit, extend the drill bit into the preformed hole, and sequentially install the second rod body, …, the m +1-th rod body on the top end of the first rod body until the bottom end of the drill bit reaches the groundwater depth position, and the bottom end of the m +1-th rod body is near the ground; m is an integer greater than or equal to 0; p = 1; install the p -th sampling tube into the sampling drill rod, and install a top cap on the top end of the m +1-th rod body; the sequentially connected top cap, rod body and drill bit form a sampling drill rod, and connect the sampling drill rod to the negative pole of the adjustable power supply; Step 203, adjust the output voltage of the adjustable power supply according to the collected formation conductivity, formation temperature, the length of the sampling drill rod below the groundwater depth and the penetration speed value of the sampling drill rod; connect the adjustable power supply to the electrode plates and the sampling drill rod, electrolyze the pore water in the soil around the sampling drill rod to generate bubbles; at the same time, the vertical vibration unit drives the sampling drill rod to reciprocate vertically to promote the liquefaction of the soil near the sampling drill rod, thereby reducing the disturbance; the traction unit drives the vertical vibration unit and the sampling drill rod to penetrate deep into the formation for sampling; when the m + p -th rod body is completely pressed into the formation, turn off the adjustable power supply, and the vertical vibration unit and the traction unit stop working; take out the p -th sampling tube to obtain the p -th soil sample below the groundwater level; Step 204, install the m + p +1-th rod body on the top end of the m + p +1-th rod body, p increase the value of p by 1; install the m+ p Install a top cap at the top of the root rod body; the top cap, rod body, and drill bit connected in sequence form a sampling drill rod, connect the sampling drill rod to the negative pole of the adjustable power supply; connect the top cap to the vertical vibration unit; repeat step 203 until the soil sample within the preset sampling depth range is taken out.

[0014] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: A high-fidelity soil collection method based on pore water electrolysis and drag reduction provided by the present invention. During the process of collecting soil samples below the groundwater level, several electrode plates are inserted around the sampling point. The electrode plates are energized as the positive pole, and the sampling drill rod is energized as the negative pole to electrolyze the interstitial water in the soil near the sampling drill rod to generate bubbles. On the one hand, under the vibration load, the bubbles significantly extend the drainage path through the cyclic compression-expansion effect, enhance the accumulation of excess pore water pressure, and thus promote soil liquefaction; on the other hand, under the vibration action, the bubbles can occupy a certain volume of soil pores, interfere with the effective stress transfer between particles, and the extension of the force chain is blocked, prompting the rearrangement of soil particles within a smaller range. In addition, the bubbles can form a gas-liquid mixed lubricating layer between the contact surface of the sampling drill rod and the soil, reducing the direct frictional contact between the surface of the sampling drill rod and soil particles. And due to the compressibility of the bubbles, bubbles with an appropriate volume can dynamically adjust the interface state during vibration, reducing the friction coefficient, thereby reducing the disturbance of the soil sample during the sampling process. Moreover, by adjusting the electrolysis voltage in real time according to the sampling depth, soil layer resistivity, and temperature, it is possible to ensure the bubble content at the contact interface between the sampling drill rod and the soil layer, provide conditions for the disordered movement and liquefaction suspension of soil particles by instantaneously adjusting the soil pore saturation, and enhance the sampling fidelity effect. The high-fidelity soil collection method based on pore water electrolysis and drag reduction provided by the present invention reduces the disturbance and prevents obvious changes in the shape of the soil sample when collecting soil samples below the groundwater level, improving the sampling fidelity effect of the soil sample. Description of the Drawings

[0015] Figure 1 is the flowchart of the method of the embodiment of the present invention; Figure 2 is the construction schematic diagram of the method of the embodiment of the present invention; Figure 3 is Figure 2 the distribution schematic diagram of the electrode plates in

[0016] In the figure: sampling drill rod 1, rod body 11, top cap 12, drill rig 2, adjustable power supply 3, electrode plate 4, traction unit 5, vertical vibration unit 6, fixture 7, groundwater level 8, ground 9. Detailed Embodiments

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

[0018] An embodiment of the present invention provides a method for high-fidelity soil collection based on electrolytic drag reduction of pore water, as follows Figure 1 shown, which includes the following steps: Step 10, drill to the groundwater level 8 at the sampling point to form a pre-drilled hole.

[0019] Step 20, insert a plurality of electrode plates 4 around the sampling point, and the insertion depth of the electrode plates 4 is consistent with the preset sampling depth. Insert the sampling drill rod 1 into the pre-drilled hole, connect the sampling drill rod 1 to the negative pole of the adjustable power supply 3, and connect the electrode plates 4 to the positive pole of the adjustable power supply 3. During the process of the traction unit 5 driving the sampling drill rod to penetrate downward below the groundwater level to collect soil samples, the electrode plates and the sampling drill rod are energized, electrolyzing the interstitial water in the soil near the sampling drill rod to generate bubbles. At the same time, the vertical vibration unit 6 drives the sampling drill rod 1 to reciprocate vertically, promoting the liquefaction of the soil near the sampling drill rod and reducing the resistance during the downhole drilling process until the soil samples within the preset sampling depth range are taken out.

[0020] The method of the embodiment of the present invention uses a low-disturbance drill to collect soil samples below the groundwater level. As Figure 2 shown, the low-disturbance drill includes a drill rig 2, a traction unit 5, a vertical vibration unit 6, a fixture 7 and a sampling drill rod. The traction unit 5 is slidably installed on the guide beam of the drill rig 2, the vertical vibration unit 6 is installed on the traction unit 5, and the fixture 7 is installed on the vertical vibration unit 6. The fixture 7 is used to clamp the sampling drill rod. The traction unit 5 is used to drive the sampling drill rod to move along the guide beam of the drill rig, drive the sampling drill rod to penetrate downward into the formation and drive the sampling drill rod to be pulled out of the formation. The vertical vibration unit 6 is used to drive the sampling drill rod to reciprocate vertically. Both the traction unit 5 and the vertical vibration unit 6 adopt existing structures.

[0021] The sampling drill rod includes a drill bit, a hollow rod body 11 and a top cap 12. The top end of the rod body 11 is adapted to the top cap 12, the bottom end is adapted to the drill bit, and the top end and the bottom end of the rod body are adapted. In use, the top cover, multiple rod bodies and the drill bit are connected in sequence from top to bottom to form a sampling drill rod. Among them, the number of rod bodies is determined according to the preset sampling depth on site. The fixture 7 clamps the top cap 12, and the traction unit 5 drives the sampling drill rod to penetrate downward into the formation through the vertical vibration unit and the fixture, and at the same time, the vertical vibration unit 6 drives the sampling drill rod to reciprocate vertically through the fixture.

[0022] Preferably, a temperature and resistivity in-situ acquisition device is provided at the bottom end of the drill bit. The temperature and resistivity in-situ acquisition device is an existing device, which is used to collect the formation conductivity and formation temperature at different depths as the drill bit drills down. A depth sensor is provided on the ground, and its movable end is installed on the fixture, which is used to collect the length of the sampling drill rod below the groundwater depth.

[0023] Preferably, in step 20, the frequency of the exciting force generated by the vertical vibration unit is 30 - 150 Hz.

[0024] Preferably, the amplitude of the vertical vibration unit is determined by formula (1): Formula (1) In the formula, represents the amplitude of the vertical vibration unit, with the unit of mm. represents the median particle size of the soil, with the unit of mm; 50% by mass of all soil particles have a particle size exceeding and 50% of the particles have a particle size lower than . represents the shape adjustment coefficient, with a value range of -1.50 to -0.70, dimensionless. I p represents the plasticity index of the soil, dimensionless. I p0 represents the reference plasticity index of the soil, with a value range of 4 - 7, dimensionless. β represents the activity adjustment coefficient, with a value range of 0.15 - 0.45, with the unit of mm.

[0025] In this embodiment, the amplitude of the vertical vibration unit is determined according to the particle size of the soil particles and the plasticity index of the soil, and the soil near the contact surface between the sampling drill rod and the soil is liquefied, so that a liquefied zone with a suitable thickness range can be obtained, reducing the degree of disturbance and damage.

[0026] Preferably, in step 20, the drilling parameters are collected in real time and transmitted to the adjustable power supply 3, and the adjustable power supply 3 adjusts its output voltage in real time according to the drilling parameters. Among them, the drilling parameters include the formation conductivity, formation temperature, the length of the sampling drill rod below the groundwater depth, and the penetration speed value of the sampling drill rod.

[0027] Specifically, the output voltage is determined by formula (2): Formula (2) In the formula, represents the output voltage, with the unit of v; represents the distance adjustment coefficient between the electrode plate and the sampling point plane, with a value range of 2.5 - 4.3, with the unit of m 3 ⋅mol⋅min⋅Ω⋅kg -1 ; represents the diameter of the sampling drill rod, with the unit of cm; represents the median particle size of the soil, with the unit of mm; represents the penetration speed value of the sampling drill rod, with the unit of m / min; represents the length of the sampling drill rod below the groundwater depth, with the unit of m; represents the formation conductivity, with the unit of mS / cm; represents the ideal gas constant, with a value of 8.31 and the unit of J·mol -1 ·K -1 ; represents the formation temperature, with the unit of K.

[0028] Preferably, step 20 specifically includes: Step 201, insert a plurality of electrode plates 4 around the sampling point. As Figure 2 shown, the insertion depth of the electrode plate 4 is consistent with the preset sampling depth, and connect the electrode plate 4 to the positive pole of the adjustable power supply 3.

[0029] Preferably, as Figure 3 shown, a plurality of electrode plates 4 are connected in sequence through wires, and one of the electrode plates is connected to the positive pole of the adjustable power supply 3. The plurality of electrode plates are evenly arranged around the sampling point.

[0030] The number of the electrode plates 4 is 4 - 8. If the number of the electrode plates 4 is too small, it will cause the reduction of the electron transfer efficiency between the electrode plate 4 and the sampling drill pipe, the uneven distribution of bubbles on the surface of the sampling drill pipe, and the uneven deformation of the surrounding soil body, reducing the integrity of the soil sample. If the number of the electrode plates 4 is too large, it will take a long time in the installation and recovery process of the electrode plates 4, increasing the sampling time cost, and too many electrode plates 4 will also occupy more construction working surfaces, resulting in a significant reduction in the sampling work efficiency.

[0031] Step 202, install the first rod body at the top of the drill bit, extend the drill bit into the pre - formed hole, and install the second rod body, …, the m +1th rod body in sequence at the top of the first rod body until the bottom end of the drill bit reaches the groundwater level position, and the bottom end of the m +1th rod body is near the ground 9. Among them, m is an integer greater than or equal to 0. p =1. Install the p th sampling tube into the sampling drill pipe, and install a top cap at the top of the m +1th rod body. The top cap 12, the rod body 11 and the drill bit connected in sequence form the sampling drill pipe. Connect the sampling drill pipe to the negative pole of the adjustable power supply. Connect the top cap 12 to the vertical vibration unit 6.

[0032] Step 203: Adjust the output voltage of the adjustable power supply according to the collected formation conductivity, formation temperature, the length of the sampling drill pipe below the groundwater depth, and the penetration speed value of the sampling drill pipe; Connect the adjustable power supply to the electrode plate and the sampling drill pipe, and electrolyze the interstitial water in the soil around the sampling drill pipe to generate bubbles. At the same time, the vertical vibration unit 6 drives the sampling drill pipe to reciprocate vertically, promoting the liquefaction of the soil near the sampling drill pipe 1, thereby reducing disturbance. The traction unit 5 drives the vertical vibration unit 6 and the sampling drill pipe to penetrate deep into the formation for sampling. When the m + p th rod body is completely pressed into the formation, the adjustable power supply stops outputting voltage, and the vertical vibration unit and the traction unit stop working. Separate the vertical vibration unit from the top cap, separate the top cap from the m + p th rod body, and take out the p th sampling tube to obtain the p th section of soil sample below the groundwater level.

[0033] Step 204: Install the m + p th + 1 rod body at the top of the m + p th rod body, and increase the value of p by 1. Install the p th sampling tube into the sampling drill pipe, and install the top cap at the top of the m + p th rod body. The sequentially connected top cap, rod body, and drill bit form the sampling drill pipe, and connect the sampling drill pipe to the negative electrode of the adjustable power supply. Connect the top cap 12 to the vertical vibration unit 6. Repeat Step 203 until the soil samples within the preset sampling depth range are taken out.

[0034] In the above embodiment, during the downward penetration sampling process, the electrolysis voltage is adjusted in real time according to the sampling depth, the soil resistivity at this depth, and the soil temperature, which can ensure the bubble content at the interface between the sampling drill pipe and the soil layer. Through the instant adjustment of soil pore saturation, conditions are provided for the disordered movement and liquefaction suspension of soil particles, enhancing the sampling fidelity effect.

[0035] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above specific embodiments. The above specific embodiments and the descriptions in the specification are only for further explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A soil high-fidelity collection method based on pore water electrolysis drag reduction, characterized in that: The following steps are involved: Step 10, drilling to the groundwater level (8) at the sampling point to form a pre-drilled hole; Step 20, inserting a plurality of electrode plates (4) around the sampling point, the insertion depth of the electrode plates (4) being consistent with the preset sampling depth; inserting the sampling drill rod (1) from the pre-formed hole, connecting the sampling drill rod (1) to the negative pole of the adjustable power supply (3), and connecting the electrode plate (4) to the positive pole of the adjustable power supply (3); when the traction unit (5) drives the sampling drill rod to penetrate below the groundwater level to collect soil samples, the electrode plates and the sampling drill rod are energized to electrolyze the pore water in the soil near the sampling drill rod to generate bubbles; at the same time, the vertical vibration unit (6) drives the sampling drill rod (1) to vibrate back and forth in the vertical direction, inducing liquefaction of the soil near the sampling drill rod, until the soil sample within the preset sampling depth range is taken out.

2. The soil high-fidelity collection method based on pore water electrolysis drag reduction according to claim 1 is characterized in that: The amplitude of the vertical vibration unit (6) is determined using formula (1): Formula (1) In the formula, Indicates the amplitude of the vertical vibration unit, in mm; It represents the median particle size of soil in mm; It represents the shape adjustment coefficient, with a value range of -1.50 to -0.70 and is dimensionless; I p It represents the plasticity index of soil, dimensionless; I p0 It represents the base plasticity index of soil, ranging from 4 to 7, dimensionless; β It represents the activity adjustment coefficient, ranging from 0.15 to 0.45, in units of mm.

3. The soil high-fidelity collection method based on pore water electrolysis drag reduction according to claim 1 is characterized in that: In step 20, drilling parameters are collected in real time and transmitted to the adjustable power supply (3), and the adjustable power supply (3) adjusts the output voltage in real time according to the drilling parameters; the drilling parameters include formation conductivity, formation temperature, the length of the sampling drill rod below the groundwater burial depth, and the penetration speed value of the sampling drill rod.

4. The soil high-fidelity collection method based on pore water electrolysis drag reduction according to claim 3 is characterized in that: In step 20, the output voltage is determined using formula (2): Formula (2) In the formula, Indicates the output voltage, the unit is v; Indicates the distance adjustment coefficient between the electrode plate and the sampling point. The value range is 2.5 to 4.3, and the unit is m. 3 ⋅mol⋅min⋅Ω⋅kg -1 ; Indicates the diameter of the sampling drill rod, in cm; It represents the median particle size of soil in mm; Indicates the penetration speed of the sampling drill rod, in m / min; Indicates the length of the sampling drill rod below the groundwater depth, in meters; Indicates formation conductivity, in mS / cm; represents the ideal gas constant, with a value of 8.31 and a unit of J·mol -1 ·K -1 ; Represents the formation temperature in K.

5. The soil high-fidelity collection method based on pore water electrolysis drag reduction according to claim 3 is characterized in that: The formation conductivity and formation temperature are both collected by an in-situ temperature and resistivity collection device installed at the bottom end of the sampling drill rod (1).

6. The soil high-fidelity collection method based on pore water electrolysis drag reduction according to claim 3 is characterized in that: The length of the sampling drill rod below the groundwater burial depth is acquired by a depth sensor placed on the ground (9) and having a movable end connected to a clamp (7).

7. The soil high-fidelity acquisition method based on pore water electrolysis drag reduction according to claim 1 is characterized in that: A plurality of electrode plates are connected in sequence through wires, and one of the electrode plates is connected to the positive electrode of the adjustable power supply.

8. The soil high-fidelity collection method based on pore water electrolysis drag reduction according to claim 1 is characterized in that: Several electrode plates are evenly arranged around the sampling points.

9. The soil high-fidelity collection method based on pore water electrolysis drag reduction according to claim 1 is characterized in that: The number of electrode plates is 4 to 8.

10. The soil high-fidelity collection method based on pore water electrolysis drag reduction according to claim 4 is characterized in that: The step 20 specifically includes: Step 201, inserting a plurality of electrode plates (4) around the sampling point, wherein the insertion depth of the electrode plates is consistent with the preset sampling depth, and connecting the electrode plates (4) to the positive electrode of the adjustable power supply (3); Step 202, install the first rod body on the top of the drill bit, insert the drill bit into the pre-formed hole, and install the second, ..., and third rod bodies on the top of the first rod body in sequence. m +1 rod, until the bottom of the drill bit reaches the groundwater depth, and the m +1 pole with the bottom end near the ground; m is an integer greater than or equal to 0; p =1; p The sampling tube is installed in the sampling drill pipe. m +1 A top cap is installed on the top of the rod body; the top cap, rod body and drill bit connected in sequence constitute a sampling drill rod, and the sampling drill rod is connected to the negative pole of the adjustable power supply; Step 203, according to the collected layer conductivity, formation temperature, the length of the sampling drill rod below the groundwater burial depth and the penetration speed value of the sampling drill rod, the output voltage of the adjustable power supply is adjusted; the adjustable power supply is connected to the electrode plate and the sampling drill rod, and the pore water in the soil around the sampling drill rod is electrolyzed to generate bubbles; at the same time, the vertical vibration unit (6) drives the sampling drill rod to vibrate back and forth in the vertical direction, promoting the liquefaction of the soil near the sampling drill rod (1), thereby reducing disturbance; the traction unit (5) drives the vertical vibration unit (6) and the sampling drill rod to penetrate deep into the formation for sampling; when the m + p When the rod body is completely pressed into the ground, turn off the adjustable power supply, and stop the vertical vibration unit and the traction unit; take out the first p A sampling tube was taken to obtain the first p Section soil samples; Step 204, in the m + p The top of the rod is installed m + p +1 rod, p Increase the value of by 1; p The sampling tubes are installed in the sampling drill pipe. m + p A top cap is installed at the top of the rod body; the top cap, the rod body and the drill bit connected in sequence constitute a sampling drill rod, and the sampling drill rod is connected to the negative pole of the adjustable power supply; the top cap is connected to the vertical vibration unit; and step 203 is repeated until the soil sample within the preset sampling depth range is taken out.

Images