Ground anchor device for fixing and compacting air energy storage air bin and using method

Abstract

The invention discloses a ground anchor device for fixing and compacting an air energy storage air bin and a using method, and belongs to the technical field of foundations, the ground anchor device comprises a drill bit provided with a cavity, a plurality of fixing plates are evenly arranged on the inner wall of the cavity in the circumferential direction with the axis of the drill bit as the axis, and an inserting groove is formed between each fixing plate and the inner wall of the cavity; a movable plate capable of moving along the inner wall of the cavity is inserted into each slot; and meanwhile, the top of the cavity is detachably connected with an ejector rod for jacking the drill bit into the ground. Compared with the prior art that an air bin is matched with a large-volume concrete strip foundation or pile foundation, a large amount of concrete can be saved, and therefore the manufacturing cost is reduced, and the cost is saved.

Description

Technical Field

[0001] The present invention belongs to the technical field of foundation, and specifically relates to a ground anchor device for fixing a compacted air energy storage gas bin and a use method thereof. Background Art

[0002] Compressed-Air Energy Storage (CAES) is a technology that uses compressed air to store energy. This technology uses electricity to compress air during the off-peak period of the power grid and stores the high-pressure air in caves or pressure vessels. When the peak period of the power grid load arrives, the compressed air is released to drive the steam turbine to generate electricity.

[0003] In the energy storage stage, the surplus electricity during the off-peak period of the power grid is used to drive the compressor to compress the carbon dioxide gas at normal temperature and pressure into a liquid or supercritical state. The large amount of heat energy generated in this process is stored in the heat storage device through the heat exchanger. In the energy release stage, when the power grid is in peak demand, the stored high-pressure liquid or supercritical carbon dioxide is released, and the previously stored heat energy is used to heat the carbon dioxide to a supercritical state through the reheater. Supercritical carbon dioxide has high energy density and good fluidity, which drives the turbine to expand and do work, thereby driving the generator to generate electricity and realize the release of electricity.

[0004] The carbon dioxide compressed air energy storage unit is an above-ground air membrane gas storage unit, which is generally several hundred meters long and more than a hundred meters wide. Compared with underground compressed air energy storage and above-ground steel tank compressed air energy storage, it has the characteristics of low cost, wide applicability, and no geographical restrictions.

[0005] The carbon dioxide compressed air energy storage gas storage tank has a very small deadweight, and the gas tank mainly bears the upward vertical load. Conventional projects use the deadweight of strip foundations or reinforced concrete pile foundations to resist the upward load. However, in the existing technology, it is very uneconomical to match the air film gas tank with a large volume of concrete strip foundations or pile foundations. Summary of the invention

[0006] In order to solve the problem of high cost caused by the combination of air film gas chamber with large concrete strip foundation or pile foundation in the prior art, the present invention provides a ground anchor device for fixing compacted air energy storage gas chamber and a method for using the ground anchor device, which can save costs by driving a drill bit into the ground and connecting the drill bit and the gas chamber with a pull rope.

[0007] The technical solution adopted by the ground anchor device and the use method for fixing the compacted air energy storage gas bin of the present invention is:

[0008] A ground anchor device for fixing a compacted air energy storage gas chamber, characterized in that it includes a drill bit with a cavity, and a plurality of fixed plates are evenly arranged on the inner wall of the cavity with the axis of the drill bit as the axis center, a slot is provided between each fixed plate and the inner wall of the cavity, and each slot is inserted with a movable plate that can move along the inner wall of the cavity; at the same time, the top of the cavity is detachably connected to a push rod for pushing the drill bit into the ground.

[0009] A further improvement of the technical solution of the present invention is that each movable plate is fixedly connected to a baffle perpendicular to itself on one side facing the top of the cavity.

[0010] A further improvement of the technical solution of the present invention is that each baffle is connected to a pull rope that drives the corresponding movable plate to move along the inner wall of the cavity.

[0011] A method for using a ground anchor device for fixing a compacted air energy storage gas bin, characterized in that: using the above-mentioned ground anchor device includes the following two methods:

[0012] 1) Push the drill bit into the ground to the specified depth and connect the pull rope to the gas chamber foundation;

[0013] 2) Push the drill bit into the ground to a specified depth, pour concrete in the hole formed by the drill bit and the cavity of the drill bit, and then connect the pull rope to the gas chamber foundation.

[0014] A further improvement of the above technical solution of the present invention is that: Method 1 comprises the following steps:

[0015] S1.1. Place the drill bit at the position on the ground where it is needed to be drilled, arrange the mandrel vertically, and make one end of the mandrel contact the top of the drill bit cavity. At this time, the pull rope is located around the mandrel and arranged along the top length;

[0016] S1.2. Place the hydraulic pile driver in contact with the other end of the push rod, and use the hydraulic pile driver to squeeze the push rod and the drill bit downward until the drill bit moves downward to the specified depth;

[0017] S1.3. Pull the pull rope upwards to move the movable plate outward along the inner wall of the cavity and insert it into the soil around the drill bit, and then take out the push rod;

[0018] S1.4. Fix the pull rope to the gas tank foundation on the ground.

[0019] A further improvement of the above technical solution of the present invention is that: Method 2 comprises the following steps:

[0020] S2.1. Place the drill bit at the position on the ground where it is needed to be drilled, arrange the mandrel vertically, and make one end of the mandrel contact the top of the drill bit cavity. At this time, the pull rope is located around the mandrel and arranged along the top length;

[0021] S2.2. Put the hydraulic pile driver in contact with the other end of the push rod, and use the hydraulic pile driver to squeeze the push rod and the drill bit downward until the drill bit moves downward to the specified depth;

[0022] S2.3. Pull the pull rope upwards to move the movable plate outward along the inner wall of the cavity and insert it into the soil around the drill bit;

[0023] S2.4. Take out the push rod and tighten the pull rope upwards, pouring concrete into the cavity of the drill bit and the hole formed by the downward movement of the drill bit;

[0024] S2.5. Fix the pull rope to the gas tank foundation on the ground.

[0025] The further improvement of the above technical solution of the present invention is that: in method 1, the standard value of the pull-out bearing capacity after the drill bit drills into the ground and the movable plate is unfolded is,

[0026] Q uk =γ×q pk ×π×(D 2 2 -D 1 2 ) / 4

[0027] In the formula, Q uk It is the standard value of the pull-out bearing capacity after the drill bit is drilled into the ground and the movable plate is unfolded;

[0028] q pk is the standard value of the ultimate end resistance of the soil layer where the drill bit is located;

[0029] γ is the reduction coefficient, ranging from 0.4 to 0.7, which is related to the expansion area of ​​the movable plate and the soil layer. The larger the expansion area, the larger the value of γ, and the larger the value of clay soil;

[0030] D 1 is the diameter of the drill bit;

[0031] D 2 It is the diameter of the movable plate after unfolding.

[0032] The further improvement of the above technical solution of the present invention is that: in method 2, the standard value of the pull-out bearing capacity after the drill bit drills into the ground and the movable plate is unfolded is,

[0033] Q uk =λ×D 1 ×∑l i ×β i +γ×q pk ×π×(D 2 2 -D 1 2 ) / 4

[0034] In the formula, Quk It is the standard value of the pull-out pile bearing capacity after the drill bit is drilled into the ground and the movable plate is deployed;

[0035] l i is the thickness of each soil layer within the rope pull range;

[0036] β i is the standard value of the extreme side resistance of the i-th layer within the rope pulling range;

[0037] q pk is the standard value of the ultimate end resistance of the soil layer where the drill bit is located;

[0038] λ is the pull-out coefficient, which is 0.5-0.7 for sandy soil and 0.7-0.8 for clay soil and silt soil;

[0039] γ is the reduction coefficient, ranging from 0.4 to 0.7, which is related to the expansion area of ​​the movable plate and the soil layer. The larger the expansion area, the larger the value of γ, and the larger the value of clay soil;

[0040] D 1 is the diameter of the drill bit;

[0041] D 2 It is the diameter of the movable plate after unfolding.

[0042] Due to the adoption of the above technical solution, the technical advances achieved by the present invention include:

[0043] The drill bit provided in the present invention can facilitate the whole present invention to be drilled into the ground; the push rod provided in the present invention facilitates the hydraulic pile driver to push the drill bit into the ground, and the push rod can be reused after being separated from the drill bit; the movable plate provided in the present invention can move upward along the inner wall of the cavity after the drill bit drills into the ground, so as to be inserted into the soil around the drill bit, thereby achieving the purpose of fixing the drill bit; the pull rope provided in the present invention can, on the one hand, drive the movable plate to move upward to the specified position, and on the other hand, can be connected to the air chamber foundation after the drill bit is fixed, thereby achieving the purpose of fixing the air chamber.

[0044] The baffle plate provided in the present invention can prevent the movable plate from being separated from the slot when the movable plate moves upward along the inner wall of the cavity.

[0045] Compared with the prior art in which the air chamber is combined with a large-volume concrete strip foundation or pile foundation, the present invention can save a large amount of concrete, thereby reducing the construction cost and saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a schematic diagram of the three-dimensional structure of the ground anchor device of the present invention;

[0047] Figure 2 It is a structural schematic diagram of the ground anchor device of the present invention;

[0048] Figure 3 , Figure 4 , Figure 5 and Figure 6 It is a schematic diagram of the structure when the method 1 of the present invention is used;

[0049] Figure 7 is a schematic structural diagram of the movable plate of the ground anchor device of the present invention after being unfolded;

[0050] Figure 8 It is a structural schematic diagram when the second method of the present invention is used.

[0051] In the accompanying drawings: 1, drill bit; 11, cavity;

[0052] 2. Fixed plate; 3. Movable plate; 31. Baffle; 32. Pull rope;

[0053] 4. Top rod; 5. Ground; 6. Concrete. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in combination with specific implementation methods and with reference to the accompanying drawings. In the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0055] The invention provides a ground anchor device for fixing a compacted air energy storage gas bin and a use method thereof.

[0056] Embodiment 1

[0057] This embodiment provides a ground anchor device for fixing a compacted air energy storage tank. Figure 1 and Figure 2 As shown, it includes a drill bit 1, which has a cavity 11 inside, and a plurality of fixed plates 2 are fixedly connected to the inner wall of the cavity 11, the plurality of fixed plates 2 are evenly arranged circumferentially with the axis of the drill bit 1 as the axis center, and a slot is provided between each fixed plate 2 and the inner wall of the cavity 11, each slot is plugged with a movable plate 3 that passes through the slot, the fixed plate 2 and the movable plate 3 are adapted to the inner wall of the cavity 11, and at the same time, a baffle 31 perpendicular to itself is fixedly connected to the bottom end of each movable plate 3, and each baffle 31 is fixedly connected to a pull rope 32 that drives the movable plate 3 to move; the ground anchor device of the present invention also includes a push rod 4 detachably connected to the drill bit 1, when the push rod 4 is connected to the drill bit 1, the push rod 4 is vertically arranged, the bottom end of the push rod 4 is located between the plurality of movable plates 3 and contacts the inner wall at the top of the cavity 11, and the push rod 4 and the drill bit 1 can be separated by removing the push rod 4 from between the movable plates 3. In this embodiment, the drill bit 1 is a steel cone, the movable plate 3 and the fixed plate 2 are both made of steel, the pull rope 32 is a steel wire rope commonly used in the prior art, and the push rod 4 is a steel pipe commonly used in the prior art.

[0058] In this embodiment, the pull ropes 32 are arranged in two ways. One arrangement is that each pull rope 32 is arranged separately and not entangled together, such as Figure 1 Another arrangement is that the upper portion of all the pull ropes 32 are wound together and merged into one, such as Figure 2 , 3 , 4, 5, 6, and 8.

[0059] Embodiment 2

[0060] This embodiment provides a method for using a ground anchor device for fixing a compressed air energy storage gas bin, which includes the following two methods:

[0061] Method 1: Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, S1.1, place the drill bit 1 at the position where the ground 5 needs to be drilled, arrange the mandrel 4 vertically, and make one end of the mandrel 4 contact the top of the cavity 11 of the drill bit 1, at this time, the pull rope 32 is located around the mandrel 4 and arranged along the top length.

[0062] S1.2. The hydraulic pile driver is brought into contact with the other end of the push rod 4, and the push rod 4 and the drill bit 1 are squeezed downward by the hydraulic pile driver until the drill bit 1 moves downward to a specified depth.

[0063] S1.3. Pull the pull rope 32 upward to move the movable plate 3 outward along the inner wall of the cavity 11 and insert it into the soil around the drill bit 1, and then take out the push rod 4.

[0064] S1.4. Fix the pull rope 32 to the gas chamber foundation on the ground 5.

[0065] This method is suitable for hard soil layers. At the same time, the standard value of the pull-out bearing capacity after the drill bit 1 drills into the ground 5 and the movable plate 3 is unfolded in method 1 is,

[0066] Q uk =γ×q pk ×π×(D 2 2 -D 1 2 ) / 4

[0067] In the formula, Q uk is the standard value of the pull-out bearing capacity after the drill bit 1 is drilled into the ground 5 and the movable plate 3 is unfolded;

[0068] q pk is the standard value of the ultimate end resistance of the soil layer where the drill bit 1 is located;

[0069] γ is the reduction coefficient, ranging from 0.4 to 0.7, which is related to the expansion area of ​​the movable plate 3 and the soil layer. The larger the expansion area, the larger the value of γ, and the larger the value of clay soil;

[0070] D 1 is the diameter of drill bit 1;

[0071] D 2 It is the diameter of the movable plate 3 after unfolding.

[0072] Compared with the prior art, this method does not need to pour concrete 6, thereby saving a large amount of concrete 6, reducing construction costs and saving costs.

[0073] Method 2: Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown, S2.1, place the drill bit 1 at the position where the ground 5 needs to be drilled, arrange the top rod 4 vertically, and make one end of the top rod 4 contact the top of the cavity 11 of the drill bit 1. At this time, the pull rope 32 is located around the top rod 4 and arranged along the top length.

[0074] S2.2. The hydraulic pile driver is brought into contact with the other end of the push rod 4, and the push rod 4 and the drill bit 1 are squeezed downward by the hydraulic pile driver until the drill bit 1 moves downward to a specified depth.

[0075] S2.3. Pull the pull rope 32 upward to move the movable plate 3 outward along the inner wall of the cavity 11 and insert it into the soil around the drill bit 1.

[0076] S2.4. Take out the push rod 4 and tighten the pull rope 32 upwards, and pour concrete 6 into the cavity 11 of the drill bit 1 and the hole formed by the downward movement of the drill bit 1.

[0077] S2.5. Fix the pull rope 32 to the gas chamber foundation on the ground 5.

[0078] In the second method, the standard value of the pull-out bearing capacity after the drill bit 1 is drilled into the ground 5 and the movable plate 3 is unfolded is:

[0079] Q uk =λ×D 1 ×∑l i ×β i +γ×q pk ×π×(D 2 2 -D 1 2 ) / 4

[0080] In the formula, Q uk is the standard value of the pull-out pile bearing capacity after the drill bit 1 is drilled into the ground 5 and the movable plate 3 is unfolded;

[0081] l i is the thickness of each soil layer within the range of the pull rope 32;

[0082] β i is the standard value of the extreme side resistance of the i-th layer within the range of the pull rope 32;

[0083] q pk is the standard value of the ultimate end resistance of the soil layer where the drill bit 1 is located;

[0084] λ is the pull-out coefficient, which is 0.5-0.7 for sandy soil and 0.7-0.8 for clay soil and silt soil;

[0085] γ is the reduction coefficient, ranging from 0.4 to 0.7, which is related to the expansion area of ​​the movable plate 3 and the soil layer. The larger the expansion area, the larger the value of γ, and the larger the value of clay soil;

[0086] D 1 is the diameter of drill bit 1;

[0087] D 2 It is the diameter of the movable plate 3 after unfolding.

[0088] Compared with the prior art, this method only needs to pour a small amount of concrete 6 in the cavity 11 of the drill bit 1 and the hole formed by the downward movement of the drill bit 1, thereby saving a large amount of concrete 6, reducing the construction cost and saving costs.

[0089] Embodiment 3

[0090] This embodiment provides a method for using a ground anchor device for fixing a compacted air energy storage gas bin, the method comprising the following steps:

[0091] S3.1. Place the drill bit 1 at the position on the ground 5 where drilling is required, arrange the mandrel 4 vertically, and make one end of the mandrel 4 contact the top of the cavity 11 of the drill bit 1. At this time, the pull rope 32 is located around the mandrel 4 and arranged along the top length.

[0092] S3.2. The hydraulic pile driver is brought into contact with the other end of the push rod 4, and the push rod 4 and the drill bit 1 are squeezed downward by the hydraulic pile driver until the drill bit 1 moves downward to a specified depth.

[0093] S3.3, first take out the push rod 4, then pull the pull rope 32 upwards to move the movable plate 3 outwards along the inner wall of the cavity 11 and insert it into the soil around the drill bit 1;

[0094] S3.4. Fix the pull rope 32 to the gas chamber foundation on the ground 5.

[0095] Compared with the prior art, this method does not need to pour concrete 6, thereby saving a large amount of concrete 6, reducing construction costs and saving costs.

[0096] The method in this embodiment is different from the method one in the embodiment one in that, the method one in the embodiment one is that when the push rod 4 contacts the drill bit 1 and supports the drill bit 1, the pull rope 32 is first pulled to expand the movable plate 3 and insert it into the soil, and then the push rod 4 is taken out from the drill bit 1, which is suitable for soil layers with harder soil to prevent the drill bit 1 from being pulled out of the soil when the pull rope 32 is pulled; while the method in this embodiment is that the push rod 4 is first taken out of the drill bit 1, and then the pull rope 32 is pulled to expand the movable plate 3 and insert it into the soil, which is suitable for soil layers with softer soil.

[0097] In the above embodiments, the present invention provides a ground anchor device for fixing a compacted air energy storage silo and a method of use. The drill bit provided in the present invention can facilitate the entire present invention to be drilled into the ground; the push rod provided in the present invention facilitates the hydraulic pile driver to push the drill bit into the ground, which can be reused; the movable plate provided in the present invention can move upward along the inner wall of the cavity after the drill bit drills into the ground, thereby inserting into the soil around the drill bit to achieve the purpose of fixing the drill bit; the pull rope provided in the present invention can, on the one hand, drive the movable plate to move upward to a specified position, and on the other hand, can be connected to the silo foundation after the drill bit is fixed, thereby achieving the purpose of fixing the silo; the baffle provided in the present invention can prevent the movable plate from escaping from the slot when the movable plate moves upward along the inner wall of the cavity; at the same time, compared with the prior art in which the silo is matched with a large-volume concrete strip foundation or pile foundation, the present invention can save a large amount of concrete, thereby reducing the construction cost and saving costs.

[0098] The above-described embodiments are merely descriptions of preferred implementations of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by ordinary persons in the art to the technical solution of the present invention should fall within the protection scope of the present invention, and the technical contents for which protection is sought in the present invention have been fully recorded in the claims.

Claims

1. A ground anchor device for fixing a compacted air energy storage tank, characterized in that: The invention comprises a drill bit (1) having a cavity (11). A plurality of fixed plates (2) are evenly arranged on the inner wall of the cavity (11) with the axis of the drill bit (1) as the axis center. A slot is provided between each fixed plate (2) and the inner wall of the cavity (11). Each slot is provided with a movable plate (3) movable along the inner wall of the cavity (11). Meanwhile, a push rod (4) for pushing the drill bit (1) into the ground (5) is detachably connected to the top of the cavity (11).

2. A ground anchor device for fixing a compacted air energy storage tank according to claim 1, characterized in that: A baffle (31) perpendicular to each movable plate (3) is fixedly connected to one side of each movable plate (3) facing the top of the cavity (11).

3. A ground anchor device for fixing a compacted air energy storage tank according to claim 1, characterized in that: Each baffle plate (31) is connected to a pull rope (32) for driving the corresponding movable plate (3) to move along the inner wall of the cavity (11).

4. A method for using a ground anchor device for fixing a compacted air energy storage gas bin, characterized in that: Using the ground anchor device according to any one of claims 1 to 3 comprises the following two methods: 1) Push the drill bit (1) into the ground (5) to a specified depth, and connect the pull rope (32) to the gas chamber foundation; 2) Push the drill bit (1) into the ground (5) to a specified depth, pour concrete (6) into the hole formed by the drill bit (1) and the cavity (11) of the drill bit (1), and then connect the pull rope (32) to the air chamber foundation.

5. The method for using a ground anchor device for fixing a compacted air energy storage gas chamber according to claim 4, characterized in that: Method 1 includes the following steps: S1.

1. Place the drill bit (1) at the position on the ground (5) where drilling is required, arrange the mandrel (4) vertically, and make one end of the mandrel (4) contact the top of the cavity (11) of the drill bit (1). At this time, the pull rope (32) is located around the mandrel (4) and arranged along the length of the top; S1.2, bringing the hydraulic pile driver into contact with the other end of the push rod (4), and using the hydraulic pile driver to squeeze the push rod (4) and the drill bit (1) downward until the drill bit (1) moves downward to a specified depth; S1.

3. Pull the pull rope (32) upwards to move the movable plate (3) outwards along the inner wall of the cavity (11) and insert it into the soil around the drill bit (1), and then remove the push rod (4); S1.

4. The pull rope (32) is fixedly connected to the gas chamber foundation on the ground (5).

6. The method for using a ground anchor device for fixing a compacted air energy storage gas chamber according to claim 4, characterized in that: Method 2 includes the following steps: S2.

1. Place the drill bit (1) at the position on the ground (5) where drilling is required, arrange the mandrel (4) vertically, and make one end of the mandrel (4) contact the top of the cavity (11) of the drill bit (1). At this time, the pull rope (32) is located around the mandrel (4) and arranged along the length of the top; S2.2, bringing the hydraulic pile driver into contact with the other end of the push rod (4), and using the hydraulic pile driver to squeeze the push rod (4) and the drill bit (1) downward until the drill bit (1) moves downward to a specified depth; S2.3, pull the pull rope (32) upwards, so that the movable plate (3) moves outwards along the inner wall of the cavity (11) and is inserted into the soil around the drill bit (1); S2.4, remove the push rod (4), tighten the pull rope (32) upward, and pour concrete (6) into the cavity (11) of the drill bit (1) and the hole formed by the downward movement of the drill bit (1); S2.

5. The pull rope (32) is fixedly connected to the gas chamber foundation on the ground (5).

7. The method for using a ground anchor device for fixing a compacted air energy storage gas chamber according to claim 4, characterized in that: In method 1, the standard value of the pull-out bearing capacity after the drill bit (1) is drilled into the ground (5) and the movable plate (3) is unfolded is: Q uk =γ×q pk ×π×(D2 2 -D1 2 ) / 4 In the formula, Q uk is the standard value of the pull-out bearing capacity after the drill bit (1) is drilled into the ground (5) and the movable plate (3) is unfolded; q pk is the standard value of the ultimate end resistance of the soil layer where the drill bit (1) is located; γ is a reduction coefficient, ranging from 0.4 to 0.7, which is related to the expansion area of ​​the movable plate (3) and the soil layer. The larger the expansion area, the larger the value of γ, and the larger the value of clay soil; D1 is the diameter of the drill bit (1); D2 is the diameter of the movable plate (3) after it is unfolded.

8. The method for using a ground anchor device for fixing a compacted air energy storage gas chamber according to claim 4, characterized in that: In method 2, the standard value of the pull-out bearing capacity after the drill bit (1) is drilled into the ground (5) and the movable plate (3) is unfolded is: Q uk =λ×D1×∑l i ×β i +γ×q pk ×π×(D2 2 -D1 2 ) / 4 In the formula, Q uk is the standard value of the pull-out pile bearing capacity after the drill bit (1) is drilled into the ground (5) and the movable plate (3) is unfolded; l i is the thickness of each soil layer within the range of the pull rope (32); β i is the standard value of the extreme side resistance of the i-th layer within the range of the pull rope (32); q pk is the standard value of the ultimate end resistance of the soil layer where the drill bit (1) is located; λ is the pull-out coefficient, which is 0.5-0.7 for sandy soil and 0.7-0.8 for clay soil and silt soil; γ is a reduction coefficient, ranging from 0.4 to 0.7, which is related to the expansion area of ​​the movable plate (3) and the soil layer. The larger the expansion area, the larger the value of γ, and the larger the value of clay soil; D1 is the diameter of the drill bit (1); D2 is the diameter of the movable plate (3) after it is unfolded.

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