A soil sampling device and method based on three-dimensional induced liquefaction

Abstract

This invention provides a soil sampling device and method based on three-dimensional induced liquefaction. The soil sampling device includes a drill, a traction unit, a vertical vibration unit, a rotary vibration unit, and a sampling drill rod. The rotary vibration unit drives the sampling drill rod to rotate and vibrate around its own axis. The vertical vibration unit drives the rotary vibration unit to vibrate the sampling drill rod in the vertical direction. The traction unit drives the vertical vibration unit to drive the sampling drill rod to penetrate the stratum and pull it out of the stratum. The sampling drill rod includes a drilling rod and several connecting drill rods, both of which have internal cavities. The drilling rod has air vents. In use, the drilling rod and several connecting drill rods are connected sequentially from bottom to top. This invention provides a soil sampling device and method based on three-dimensional induced liquefaction, which reduces disturbance, prevents changes in soil structure, and improves the preservation of soil samples when collecting soil samples below the groundwater level.

Description

Technical Field

[0001] This invention belongs to the field of soil drilling and sampling technology, specifically, it relates to a soil sampling device and soil sampling method based on three-dimensional induced liquefaction. Background Technology

[0002] Existing acoustic vibration soil sampling drills and their associated control methods can create a liquefaction zone near the contact surface between the drill rod and the soil, reducing penetration resistance and compression disturbance to the surrounding soil during sampling. This improves the fidelity and quality of soil samples to some extent, and has been applied in sampling low-cohesion sandy soil strata. However, because pollutants in contaminated sites often accumulate in high-cohesion fine-grained soil layers, such as silt and silty clay, the small particle size and high cohesion of cohesive soils make it difficult to achieve a good liquefaction state under acoustic vibration. The collected samples still exhibit significant deformation, resulting in a marked change in soil structure. Therefore, there is an urgent need to improve existing acoustic vibration soil sampling drills and methods. The aim is to enhance the soil liquefaction tendency during sampling by altering the physical state of the soil near the contact surface between the drill rod and the soil, and to obtain high-quality, high-fidelity soil samples by rationally controlling the thickness of the liquefaction zone. This will provide technical support for the design and subsequent management of green, low-carbon remediation and risk management projects for contaminated sites. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a soil sampling device and method based on three-dimensional induced liquefaction, which reduces disturbance, prevents changes in soil structure, and improves the preservation effect of soil samples when collecting soil samples below the groundwater level.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] In a first aspect, the present invention provides a soil sampling device based on three-dimensional induced liquefaction, comprising a drilling rig, a traction unit, a vertical vibration unit, a rotary vibration unit, and a sampling drill rod. The sampling drill rod is sequentially mounted on the drilling rig via the rotary vibration unit, the vertical vibration unit, and the traction unit. The rotary vibration unit drives the sampling drill rod to rotate and vibrate around its own axis, and the vertical vibration unit drives the rotary vibration unit to vibrate the sampling drill rod in the vertical direction. The traction unit drives the vertical vibration unit to move along the guide beam of the drilling rig, and the rotary vibration unit drives the sampling drill rod to penetrate into the stratum and be pulled out of the stratum. The sampling drill rod includes a drilling rod and several connecting drill rods, both of which have internal cavities. The drilling rod is provided with air vents. In use, the drilling rod and several connecting drill rods are connected sequentially from bottom to top.

[0006] As a further improvement of the present invention, the drilling rod includes a hollow first rod body, on which a first air supply channel is provided along its axial direction; multiple sets of air outlet groups are provided at intervals along the axial direction on the first rod body, each set of air outlet groups including several air outlets distributed at intervals along the circumference of the first rod body, and the air outlets are connected to the first air supply channel; each air outlet is provided with a gas disperser; the connecting drill rod includes a hollow second rod body, on which a second air supply channel passes through both ends.

[0007] As a further improvement of the present invention, the spacing between two adjacent groups of air outlets is 0.3 to 0.5 m; in each group of air outlets, the ratio of the number of air outlets to the diameter of the first rod is 30 to 50 per m.

[0008] As a further improvement of the present invention, the rotary vibration unit includes a top plate, a rotary drive, a first gear, a second gear, and a clamp, the clamp being used to hold the sampling drill rod; the top plate is mounted on the vertical vibration unit, and the first gear, the second gear, and the clamp are all rotatably mounted on the top plate; the rotary drive is connected to the first gear and is used to drive the first gear to rotate; the first gear and the second gear mesh; the first gear is provided with a first lever, the second gear is provided with a second lever, and the clamp is provided with a first protrusion and a second protrusion spaced apart; in use, the rotary drive drives the first gear and drives the second gear to rotate, the first lever moves the first protrusion to make the clamp rotate forward, and the second lever moves the second protrusion to make the clamp rotate in the opposite direction; the first lever and the second lever work alternately, causing the clamp to drive the sampling drill rod to rotate in both directions.

[0009] Secondly, the present invention also provides a soil sampling method based on three-dimensional induced liquefaction, using the soil sampling device provided in the first aspect; the soil sampling method includes the following steps:

[0010] Step 10: Drill to the groundwater level;

[0011] Step 20: During the process of the sampling drill rod penetrating below the groundwater level to collect soil samples, the lowest part of the sampling drill rod ejects micro-nano bubbles outward, which enter the soil around the drilling drill rod. The vertical vibration unit drives the rotary vibration unit to drive the sampling drill rod to reciprocate in the vertical direction. The rotary vibration unit drives the sampling drill rod to rotate and vibrate around its own axis in both directions, promoting the liquefaction of the soil near the drilling drill rod until the soil sample within the preset sampling depth range is extracted.

[0012] As a further improvement of the present invention, the vibration frequencies of the vertical vibration unit and the rotary vibration unit are both 80 to 120 Hz.

[0013] As a further improvement of the present invention, the amplitude of the vertical vibration element is determined using equation (1):

[0014] Equation (1)

[0015] In the formula, This represents the amplitude of the vertical vibration element, expressed in mm. This represents the median particle size of soil particles, in mm. This represents the adjustment coefficient for the first shape parameter, with a value range of -1.3 to -0.7, and is dimensionless. I p The plasticity index of soil is dimensionless. I p0 The reference plasticity index of soil, with a value range of 4 to 7, is dimensionless. β This represents the activity adjustment coefficient, with a value range of 0.15 to 0.45, and the unit is mm.

[0016] As a further improvement of the present invention, the amplitude of the rotating vibration unit is determined using equation (2):

[0017] Equation (2)

[0018] In the formula, This represents the amplitude of the rotating vibration element; This indicates the diameter of the drill pipe, in cm. This represents the adjustment coefficient for the second shape parameter, which ranges from -13 to -7 and is dimensionless.

[0019] As a further improvement of the present invention, the flow rate of gas introduced into the drill pipe is determined using equation (3):

[0020] Equation (3)

[0021] In the formula, This indicates the flow rate of gas injected into the drill pipe, expressed in L / min. This represents the average penetration speed of the drill pipe, expressed in m / min.

[0022] This invention provides a soil sampling device and method based on three-dimensional induced liquefaction. The lowermost drilling rod of the sampling drill is equipped with air vents, and the sampling drill can undergo horizontal forward and reverse rotational vibration driven by a rotating vibration unit, and vertical reciprocating vibration driven by a vertical vibration unit. During the collection of soil samples below the groundwater level, micro-nano bubbles are introduced between the sampling drill rod and the soil contact surface. Under vibration load, the micro-nano bubbles significantly extend the drainage path through cyclic compression-expansion, enhancing the accumulation of excess pore water pressure and thus promoting soil liquefaction. Considering that clay minerals have a layered or platy structure and are mostly horizontally oriented during deposition, forming anisotropic characteristics of low vertical permeability and high horizontal permeability, at the beginning of liquefaction, excess pore water pressure tends to diffuse along the path with higher horizontal permeability, triggering dominant horizontal seepage. Simultaneously, due to the surface structure between particles, the vertical extension distance of the force chain within the liquefaction region is significantly greater than its lateral extension distance. Therefore, this invention utilizes the three-dimensional high-frequency vibration of the sampling drill rod—moving vertically up and down and rotating horizontally in both directions—combined with the effect of dissolving micro-nano bubbles in pore water to increase pore pressure. This causes the contact bonds between soil particles near the contact surface between the drill rod and the soil to break simultaneously in both the vertical and horizontal directions, inducing soil liquefaction within a smaller area and effectively reducing the thickness of the disturbed layer in the collected soil core samples. This reduces disturbance, prevents changes in soil structure, and improves the fidelity of soil samples. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a soil sampling device based on three-dimensional induced liquefaction according to an embodiment of the present invention;

[0024] Figure 2 yes Figure 1 Schematic diagram of the structure of the rotating vibration unit;

[0025] Figure 3 yes Figure 1 A cross-sectional view of the drill pipe during intermediate drilling;

[0026] Figure 4 yes Figure 1 A cross-sectional view of the drill pipe connecting the middle section;

[0027] Figure 5 yes Figure 1 A sectional view of the top cap;

[0028] Figure 6 yes Figure 1 Installation diagram of the traction unit, vertical vibration unit and rotary vibration unit.

[0029] In the diagram: Drill rod 1, first rod body 11, first gas supply channel 12, gas outlet 13, gas disperser 14, connecting drill rod 2, second rod body 21, second gas supply channel 22, micro / nano bubbles 3, top cap 4, cap body 41, third gas supply channel 42, traction unit 5, vertical vibration unit 6, rotary vibration unit 7, first gear 71, first lever 711, second gear 72, second lever 721, clamp 73, first protrusion 731, second protrusion 732, gas flow controller 8, gas storage tank 9, groundwater level 10, ground surface 11, guide beam of the drilling rig 12. Detailed Implementation

[0030] The technical solution of the present invention will be described in detail below.

[0031] This invention provides a soil sampling device based on three-dimensional induced liquefaction, such as... Figure 1 As shown, the system includes a drilling rig, a traction unit 5, a vertical vibration unit 6, a rotary vibration unit 7, and a sampling drill rod. The sampling drill rod is mounted on the rotary vibration unit 7. Figure 6 As shown, the rotary vibration unit 7 is mounted on the vertical vibration unit 6, the vertical vibration unit 6 is mounted on the traction unit 5, and the traction unit 5 is slidably mounted on the guide beam 12 of the drilling rig.

[0032] like Figure 6 As shown, the rotary vibration unit 7 drives the sampling drill rod to rotate and vibrate in both directions around its own axis. The vertical vibration unit 6 drives the rotary vibration unit 7 to cause the sampling drill rod to reciprocate in the vertical direction. The traction unit 5 drives the vertical vibration unit 6 to move along the guide beam of the drilling rig, and through the rotary vibration unit 7, drives the sampling drill rod to penetrate into the formation and be pulled out of the formation. Both the traction unit 5 and the vertical vibration unit 6 adopt existing structures.

[0033] As a preferred example, such as Figure 2As shown, the rotary vibration unit 7 includes a top plate, a rotation drive, a first gear 71, a second gear 72, and a clamp 73, which is used to hold the sampling drill rod. The top plate is mounted on the vertical vibration unit 6. The first gear 71, the second gear 72, and the clamp 73 are all rotatably mounted on the top plate via a rotating shaft. The rotation drive is connected to the first gear 71 and is used to drive the first gear 71 to rotate. The first gear 71 and the second gear 72 mesh. The first gear 71 is provided with a first lever 711, and the second gear 72 is provided with a second lever 721, which are offset from each other. The clamp 73 is provided with a first protrusion 731 and a second protrusion 732, which are spaced apart. In use, the rotation drive drives the first gear 71 to rotate, and the first gear acts as the driving wheel to drive the second gear 72 to rotate continuously. When the first lever 711 rotates to the first protrusion 731, it actuates the first protrusion 731, causing the clamp 73 to rotate clockwise or counterclockwise. After the clamp rotates forward by a preset angle, the second lever 721 rotates to the second protrusion 732, actuating the second protrusion 732, causing the clamp 73 to rotate in the opposite direction. After the clamp rotates in the opposite direction by a preset angle, the first lever 711 actuates the first protrusion 731 again, causing the clamp 73 to rotate forward. In this way, the clamp drives the sampling drill rod to rotate and vibrate in both directions.

[0034] In this embodiment, two meshing gears alternately rotate the clamp, thereby switching the clamp's forward and reverse rotation. This drives the sampling drill rod to rotate and vibrate in both directions, resulting in a large torque. The control is simple, the mechanical structure is fatigue-resistant, suitable for long-term high-frequency operation, and has low processing and maintenance costs.

[0035] The sampling drill pipe includes a drilling drill pipe 1 and a connecting drill pipe 2, both of which have internal cavities. For example... Figure 3As shown, the drilling rod 1 includes a hollow first rod body 11, the bottom end of which is tapered. A first air supply channel 12 is provided on the first rod body 11 along its axial direction, the inlet of which is located on the top surface of the first rod body 11. Multiple sets of air outlet groups are spaced apart along the axial direction on the first rod body 11. Each set of air outlet groups includes several air outlets 13 spaced apart circumferentially on the first rod body. The inlets of all air outlets 13 in each set are connected by an annular channel, which is connected to the first air supply channel 12. The outlets of the air outlets are located on the outer wall of the first rod body. Thus, the air outlets of all sets of air outlets are connected to the first air supply channel. A gas disperser 14 is provided at the outlet of each air outlet 13. The gas disperser 14 is used to generate micro / nano bubbles and prevent groundwater in the soil from entering the air outlet 13. The top end of the first rod body 11 is provided with a first threaded protrusion for connection with a connecting rod body. Preferably, the spacing between two adjacent groups of vent holes is 0.3–0.5 m. In each group of vent holes, the ratio of the number of vent holes 13 to the diameter of the first rod is 30–50 per m. If the number and spacing of the vent holes are too large, it will create irregular migration channels, preventing the overall liquefaction of the soil near the contact surface; if the number and spacing of the vent holes are too small, the wear and tear on the gas disperser will increase, reducing the economic efficiency of sampling. Setting the number and spacing of the vent holes within the above-mentioned range promotes the uniform distribution of air bubbles in the pores between the sampling drill rod and the soil contact surface, achieving synchronous liquefaction of the soil in a localized area of ​​the contact surface.

[0036] like Figure 4 As shown, the connecting drill rod 2 includes a hollow second rod body 21, on which a second air supply channel 22 extends through its upper and lower ends. The bottom end of the second rod body 21 has a first threaded groove for connecting with the drilling rod body, and the top end has a second threaded protrusion. Both the first threaded protrusion and the second threaded protrusion are adapted to the first threaded groove.

[0037] The sampling drill pipe also includes a top cap 4, such as Figure 5 As shown, the top cap 4 includes a cap body 41. The bottom end of the cap body 41 is provided with a second threaded groove for connecting to the connecting drill rod. The second threaded groove is adapted to the second threaded protrusion of the connecting drill rod. A third air supply channel 42 is provided on the cap body 41.

[0038] When using, such as Figure 1As shown, the top cover 4, multiple connecting drill rods 2, and drilling drill rod 1 are connected sequentially from top to bottom to form a sampling drill rod. The inner cavities of the connecting drill rods and drilling drill rods are connected sequentially to form a sampling chamber. The third gas supply channel 42, multiple second gas supply channels 22, and the first gas supply channel 12 are connected sequentially. The sampling tube is installed in the sampling chamber. The number of connecting drill rods is determined according to the on-site sampling depth. Preferably, the lengths of the sampling tube, drilling drill rod, and connecting drill rods are all equal. The rotary vibration unit 7 clamps the top cover 4. The traction unit 5 drives the sampling drill rod, formed by the connection of multiple connecting drill rods and drilling drill rods, downward into the formation via the vertical vibration unit 6 and the rotary vibration unit 7. At the same time, the vertical vibration unit 6 drives the sampling drill rod to reciprocate in the vertical direction via the rotary vibration unit 7. The rotary vibration unit 7 drives the sampling drill rod to rotate and vibrate in both directions around its own axis.

[0039] This invention also provides a soil sampling method based on three-dimensional induced liquefaction, using the soil sampling device described in the above embodiments. The soil sampling method includes the following steps:

[0040] Step 10: Drill down to groundwater level 10.

[0041] In step 20, during the process of the sampling drill rod penetrating below the groundwater level to collect soil samples, the lowest part of the sampling drill rod, the drilling rod 1, ejects micro-nano bubbles outwards, which enter the soil surrounding the drilling rod. The vertical vibration unit 6 drives the rotary vibration unit 7 to reciprocate vertically, and the rotary vibration unit 7 drives the sampling drill rod to rotate clockwise and counterclockwise around its own axis, promoting soil liquefaction near the drilling rod 1 until soil samples within the preset sampling depth range are extracted.

[0042] If the groundwater level is deep, and the distance between the groundwater level 10 and the ground surface 11 is greater than the length of the drilling rod, then when collecting the first soil sample below the groundwater level, at least one connecting rod needs to be connected to the top of the drilling rod until the bottom of the drilling rod reaches the groundwater level.

[0043] Step 20 specifically includes:

[0044] Step 201: Install the first, second, ..., ... drill pipes sequentially at the top of drill pipe 1. m +1 connecting drill rod 2, until the bottom of drill rod 1 reaches the groundwater level, and the first m +1 The bottom end of connecting drill rod 2 is located near the ground. Among them, m It is an integer greater than or equal to 0. p =1. The first... p The root sampling tube is inserted into the inner cavity of the drill pipe.

[0045] Step 202, in the m + pA top cap 4 is installed at the top of the connecting drill rod, and the top cap 4 is connected to the rotary vibration unit 7. Gas is introduced into the third air supply channel 41 of the top cap, and the gas enters the first air supply channel 12 of the drilling drill rod 1 through the second air supply channel connected to the drill rod, and then enters all the air outlets. The gas disperser 14 sprays out micro-nano bubbles, which enter the soil around the drilling drill rod. At the same time, the vertical vibration unit 6 drives the sampling drill rod to vibrate repeatedly in the vertical direction, and the rotary vibration unit 7 drives the sampling drill rod to rotate and vibrate in both directions around its own axis, promoting soil liquefaction near the drilling drill rod, thereby reducing disturbance. The traction unit 5 drives the vertical vibration unit 6, the rotary vibration unit 7 and the sampling drill rod to penetrate deep into the strata for sampling. When the first m + p When drill pipe 2 is fully driven into the formation, ventilation is stopped, and the vertical vibration unit, rotary vibration unit, and traction unit cease operation. The rotary vibration unit 7 is separated from the top cap, and the top cap and the... m + p The first connecting drill pipe was separated, and the second one was removed. p The sampling tube obtained the first sample below the groundwater level. p Soil sample section.

[0046] Step 203, in the m + p The top of the connecting drill pipe is installed with the first m + p +1 connecting drill rod 2. p Increase the value by 1. This will increase the value of the first... p Insert the sampling tube into the inner cavity of the drill pipe. Repeat step 202 until soil samples are extracted from the predetermined depth range.

[0047] If the groundwater level is shallow, and the distance between the groundwater level 10 and the ground surface 11 is less than the length of the drilling rod, then when collecting the first soil sample below the groundwater level, it is not necessary to install a connecting rod at the top of the drilling rod.

[0048] Step 20 specifically includes:

[0049] Step 201: Insert the first sampling tube into the inner cavity of the drilling rod, install the top cap 4 at the top of the drilling rod, and connect the top cap to the rotary vibration unit.

[0050] In step 202, gas is introduced into the third gas supply channel 41 of the top cap. The gas enters the first gas supply channel 12 of the drill rod 1, and then into all the gas outlets. The gas disperser 14 sprays out micro-nano bubbles, which enter the soil around the drill rod. Simultaneously, the vertical vibration unit 6 drives the sampling drill rod to vibrate reciprocally in the vertical direction, and the rotary vibration unit 7 drives the sampling drill rod to rotate and vibrate around its own axis, promoting soil liquefaction near the drill rod and thus reducing disturbance. The traction unit 5 drives the vertical vibration unit 6, the rotary vibration unit 7, and the sampling drill rod to penetrate deeper into the formation for sampling. When the drill rod is completely pressed into the formation, the gas supply is stopped, and the vertical vibration unit, the rotary vibration unit, and the traction unit stop working. The rotary vibration unit and the top cap are separated, the top cap and the drill rod are separated, and the first sampling tube is taken out to obtain the first soil sample below the groundwater level.

[0051] Step 203: Install the first connecting drill pipe at the top of the drilling drill pipe. n=1.

[0052] Step 204: Insert the (n+1)th sampling tube into the inner cavity of the drilling rod, install a top cap at the top of the nth connecting rod, and connect the top cap to the rotary vibration unit.

[0053] Step 205: Gas is introduced into the third gas supply channel 41 of the top cap. The gas enters the first gas supply channel 12 of the drilling rod 1 through the second gas supply channel connecting the drill rod, and then enters all the gas outlets. The gas disperser 14 sprays out micro-nano bubbles, which enter the soil around the drilling rod. Simultaneously, the vertical vibration unit 6 drives the sampling drill rod to vibrate repeatedly in the vertical direction, and the rotary vibration unit 7 drives the sampling drill rod to rotate and vibrate around its own axis, promoting soil liquefaction near the drilling rod and thus reducing disturbance. The traction unit 5 drives the vertical vibration unit 6, the rotary vibration unit 7, and the sampling drill rod to penetrate deeper into the stratum for sampling. When the nth connecting drill rod 2 is completely pressed into the stratum, the gas supply is stopped, and the vertical vibration unit, the rotary vibration unit, and the traction unit stop working. The rotary vibration unit is separated from the top cap, the top cap is separated from the nth connecting drill rod, and the (n+1)th sampling tube is taken out to obtain the (n+1)th soil sample below the groundwater level.

[0054] Step 206: Install the (n+1)th second drill rod at the top of the nth connecting drill rod. Increment the value of n by 1. Repeat steps 204 to 205 until soil samples are collected within the predetermined depth range.

[0055] Preferably, the vibration frequencies of both the vertical vibration unit 6 and the rotary vibration unit 7 are 80 to 120 Hz.

[0056] Preferably, the amplitude of the vertical vibration element is determined using equation (1):

[0057] Equation (1)

[0058] In the formula, This indicates the amplitude of the vertical vibration element, expressed in mm. This represents the median particle size of soil particles, expressed in mm; 50% of all soil particles by mass have a particle size exceeding [a certain value]. Furthermore, 50% of the particles have a diameter smaller than [missing information]. . This represents the adjustment coefficient for the first shape parameter, with a value range of -1.3 to -0.7, and is dimensionless. I p The plasticity index of soil is dimensionless. I p0 The reference plasticity index of soil ranges from 4 to 7 and is dimensionless. β This represents the activity adjustment coefficient, with a value range of 0.15 to 0.45, and the unit is mm.

[0059] In this embodiment, the amplitude of the vertical vibration unit is determined based on the particle size of the soil particles and the plasticity index of the soil. The soil near the contact surface between the drilling rod and the soil is liquefied, thereby obtaining a liquefaction zone with a suitable thickness range and reducing the degree of disturbance and damage.

[0060] The amplitude of the rotating vibration element 7 is determined using equation (2):

[0061] Equation (2)

[0062] In the formula, This represents the amplitude of the rotating vibration element; This indicates the diameter of the drill pipe, in cm. This represents the adjustment coefficient for the second shape parameter, which ranges from -13 to -7 and is dimensionless.

[0063] In this embodiment, the amplitude of the rotating vibration unit is determined based on the particle size of the soil particles and the diameter of the drilling rod. This causes the contact bonds of the soil particles near the contact surface between the drilling rod and the soil to break synchronously in both the vertical and horizontal directions, inducing soil liquefaction within a smaller area and effectively reducing the thickness of the disturbed layer when collecting soil core samples.

[0064] Preferably, the flow rate of gas injected into the drill pipe is determined using equation (3):

[0065] Equation (3)

[0066] In the formula, This indicates the flow rate of gas injected into the drill pipe, expressed in L / min. This represents the average penetration speed of the drill pipe, expressed in m / min.

[0067] In this embodiment, an appropriate amount of gas is introduced to coordinate with the drilling process, ensuring that micro-nano bubbles form a uniform gas-liquid mixed lubricating layer at the contact surface between the sampling drill rod and the soil. At the same time, the soil saturation is uniform near the contact surface, avoiding the formation of advantageous channels for bubble migration that would reduce the sampling fidelity.

[0068] Preferably, the diffusion range of the micro / nano bubbles is 0.3 to 0.6 times the length of the drill rod. This diffusion range can fully cover the disturbed area between the sampling drill rod and the soil during the sampling process, achieving optimal sampling fidelity and economy.

[0069] The foregoing has shown and described 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 to the specific embodiments described above. The specific embodiments and descriptions in the specification are merely for further illustrating the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A soil sampling device based on three-dimensional induced liquefaction, characterized in that, The system includes a drilling rig, a traction unit (5), a vertical vibration unit (6), a rotary vibration unit (7), and a sampling drill rod. The sampling drill rod is installed on the drilling rig via the rotary vibration unit (7), the vertical vibration unit (6), and the traction unit (5). The rotary vibration unit (7) drives the sampling drill rod to rotate and vibrate around its own axis. The vertical vibration unit (6) drives the rotary vibration unit (7) to vibrate the sampling drill rod in the vertical direction. The traction unit (5) drives the vertical vibration unit (6) to move along the guide beam of the drilling rig, and the rotary vibration unit (7) drives the sampling drill rod to penetrate into the formation and be pulled out of the formation. The sampling drill rod includes a drilling drill rod (1) and several connecting drill rods (2). Both the drilling drill rod (1) and the connecting drill rods (2) have internal cavities. The drilling drill rod (1) is provided with air vents (13). The drilling drill rod (1) includes a hollow first rod body (11). The first rod (11) is provided with a first air supply channel (12) arranged along its axial direction; the first rod is provided with multiple sets of air outlet groups at intervals along its axial direction, each set of air outlet groups includes several air outlets (13) distributed at intervals along the circumference of the first rod, and the air outlets (13) are connected to the first air supply channel (12); each air outlet (13) is provided with a gas disperser (14); the connecting drill rod (2) includes a hollow second rod (21), and the second rod (21) is provided with a second air supply channel (22) that runs through both ends of it; in use, the drilling drill rod (1) and several connecting drill rods (2) are connected sequentially from bottom to top, and by introducing gas into the sampling drill rod, the drilling drill rod (1) located at the bottom of the sampling drill rod sprays out micro-nano bubbles, and the micro-nano bubbles enter the soil around the drilling drill rod; the vibration frequency of the vertical vibration unit (6) and the rotational vibration unit (7) is 80 to 120 Hz.

2. The soil sampling device based on three-dimensional induced liquefaction according to claim 1, characterized in that, The spacing between two adjacent groups of air outlets is 0.3 to 0.5 m; in each group of air outlets, the ratio of the number of air outlets (13) to the diameter of the first rod is 30 to 50 per m.

3. The soil sampling device based on three-dimensional induced liquefaction according to claim 1, characterized in that, The rotating vibration unit (7) includes a top plate, a rotating drive component, a first gear (71), a second gear (72), and a clamp (73). The clamp (73) is used to hold the sampling drill rod. The top plate is mounted on the vertical vibration unit (6). The first gear (71), the second gear (72), and the clamp (73) are all rotatably mounted on the top plate. The rotating drive component is connected to the first gear (71) and is used to drive the first gear (71) to rotate. The first gear (71) meshes with the second gear (72). The first gear (71) is provided with a first lever (7). 11) The second gear (72) is provided with a second lever (721), and the clamp (73) is provided with a first protrusion (731) and a second protrusion (732) at intervals. When in use, the rotating drive unit drives the first gear and drives the second gear to rotate. The first lever (711) moves the first protrusion (731) to make the clamp (73) rotate in the forward direction, and the second lever (721) moves the second protrusion (732) to make the clamp (73) rotate in the reverse direction. The first lever (711) and the second lever (721) work in turn, so that the clamp drives the sampling drill rod to rotate and vibrate in both directions.

4. A soil sampling method based on three-dimensional induced liquefaction, characterized in that, The soil sampling device according to any one of claims 1-3 is used; the soil sampling method includes the following steps: Step 10: Drill to the groundwater level (10); Step 20: During the process of the sampling drill rod penetrating below the groundwater level to collect soil samples, gas is introduced into the sampling drill rod. The drilling rod (1) at the bottom of the sampling drill rod sprays out micro-nano bubbles, which enter the soil around the drilling rod. The vertical vibration unit (6) drives the rotary vibration unit (7) to drive the sampling drill rod to vibrate back and forth in the vertical direction. The rotary vibration unit (7) drives the sampling drill rod to rotate and vibrate in both directions around its own axis, promoting the liquefaction of the soil near the drilling rod (1) until the soil sample within the preset sampling depth range is taken out. The vibration frequencies of the vertical vibration unit (6) and the rotational vibration unit (7) are both 80 to 120 Hz.

5. The soil sampling method based on three-dimensional induced liquefaction according to claim 4, characterized in that, The amplitude of the vertical vibration element (6) is determined using equation (1): Equation (1) In the formula, This represents the amplitude of the vertical vibration element, expressed in mm. This represents the median particle size of soil particles, in mm. This represents the adjustment coefficient for the first shape parameter, with a value range of -1.3 to -0.7, and is dimensionless. I p The plasticity index of soil is dimensionless. I p0 The reference plasticity index of soil, with a value range of 4 to 7, is dimensionless. β This represents the activity adjustment coefficient, with a value range of 0.15 to 0.45, and the unit is mm.

6. The soil sampling method based on three-dimensional induced liquefaction according to claim 4, characterized in that, The amplitude of the rotating vibration element (7) is determined using equation (2): Equation (2) In the formula, This represents the amplitude of the rotating vibration element; This indicates the diameter of the drill pipe, in cm. This represents the adjustment coefficient for the second shape parameter, which ranges from -13 to -7 and is dimensionless.

7. The soil sampling method based on three-dimensional induced liquefaction according to claim 4, characterized in that, The flow rate of gas introduced into the drill pipe is determined using equation (3): Equation (3) In the formula, This indicates the flow rate of gas injected into the drill pipe, expressed in L / min. This represents the average penetration speed of the drill pipe, expressed in m / min.

8. The soil sampling method based on three-dimensional induced liquefaction according to claim 4, characterized in that, The diffusion range of micro- and nano-bubbles is 0.3 to 0.6 times the length of the drill pipe.

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