An in-situ shear testing device for soil and rock masses

Abstract

This invention discloses an in-situ shear testing device for soil and rock boreholes, belonging to the fields of geotechnical engineering and geological engineering. The device described in this invention can accurately obtain in-situ shear strength parameters within soil and rock boreholes, improving engineering design and ensuring the safety and stability of engineering projects. This in-situ shear testing device for soil and rock boreholes, employing the above-described structure, can solve the problems of difficulty in in-situ shear testing of deep soil and rock boreholes, lack of testing equipment, difficulty in radial testing, difficulty in simultaneous loading and shearing, and difficulty in multi-point in-situ testing.

Description

Technical Field

[0001] This invention relates to the fields of geotechnical engineering and geological engineering, and in particular to an in-situ shear testing device for soil and rock bodies. Background Technology

[0002] Shear strength of soil and rock is a crucial indicator in slope stability, foundation strength, and stability evaluation. In engineering practice, obtaining shear strength of soil and rock typically requires field sampling and indoor direct shear tests. However, stress release during sample collection causes disturbance to the soil and rock, leading to discrepancies between the indoor test parameters and the actual in-situ shear strength parameters. Furthermore, obtaining in-situ shear strength parameters within boreholes is challenging, and the development of suitable devices for this purpose remains a gap. Therefore, developing an in-situ shear testing device for soil and rock boreholes to accurately obtain in-situ shear strength parameters is of significant theoretical and practical value for revealing the mechanisms of soil and rock engineering disasters, improving engineering design, and ensuring engineering safety and stability. Summary of the Invention

[0003] The purpose of this invention is to provide an in-situ shear testing device for deep soil and rock boreholes, which solves the problems of difficulty in in-situ shear testing in deep soil and rock boreholes, lack of testing devices, difficulty in radial testing, difficulty in simultaneous loading and shearing, and difficulty in multi-point in-situ testing.

[0004] To achieve the above objectives, the present invention provides an in-situ shear testing device for soil and rock boreholes, comprising an axial loading system, a cutting power system, a rotation system, an upper cutter head control system, a shear testing system, and a lower cutter head control system;

[0005] The axial loading system includes a pressing cylinder, a cover plate is provided above the pressing cylinder, and a reaction plate is provided below the pressing cylinder.

[0006] The cutting power system includes a main cutting motor, which is connected to the lower base plate by bolts.

[0007] The rotation system includes a first shaft reducer, which is connected to the drill pipe via a coupling. A second shaft reducer is provided at the lower part of the drill pipe, and a first lifting nut is provided on the outside of the second shaft reducer.

[0008] The upper cutter head control system includes a first solenoid valve controller, which is connected to a first lower cover by bolts. A first drive motor is provided on the upper surface of the first lower cover. The first upper cover is fitted over the first solenoid valve controller and the first drive motor.

[0009] The shearing test system includes an upper cutting blade and a lower cutting blade. The upper cutting blade is connected to the upper blade disc via a blade shaft, and the lower cutting blade is connected to the lower blade disc via a blade shaft. A pressure block is provided between the upper and lower blade discs, and a scissor-type telescopic structure is provided inside the pressure block. The scissor-type telescopic structure is connected to the pressure block via a shaft.

[0010] The lower cutter head control system includes a second solenoid valve controller. The upper surface of the second solenoid valve controller is provided with bolts, and the side of the second solenoid valve controller is provided with a fixing bracket. The second solenoid valve controller is connected to the second upper guard through bolts and fixing bracket. The second upper guard is provided with a second drive motor inside, and a second lower guard for protection is provided below the second upper guard.

[0011] Pressure sensors are installed on the upper cutting tool, the lower cutting tool, and the pressure block.

[0012] Preferably, the upper surface of the cover plate is provided with a positioning flange, and a limiting post with limiting and unloading rebound function is provided between the cover plate and the reaction plate. The limiting post is provided with a limiting screw and a spring. A connecting plate is provided on the outside of the pressing cylinder, and the pressing cylinder is connected to the cover plate through the connecting plate.

[0013] Preferably, the main cutting motor is provided with support rods around its perimeter, and the two ends of the support rods are connected to the reaction plate and the bottom plate, respectively.

[0014] Preferably, the first shaft reducer and coupling are fitted with a cable guide ring, and the bottom end of the drill rod is provided with a bearing.

[0015] Preferably, the center of the first upper protective cover is provided with a reserved hole for the first upper protective cover, and the center of the first lower protective cover is provided with a reserved hole for the first lower protective cover.

[0016] Preferably, the upper cutter disc has an upper reserved hole at its center, a cutting gear is provided outside the upper reserved hole, and a cutting tool gear is provided outside the cutting gear. The cutting gear is connected to the upper cutting tool through the cutting tool gear. The lower cutter disc has a lower reserved hole at its center, a cutting gear is provided outside the lower reserved hole, and a cutting tool gear is provided outside the cutting gear. The cutting gear is connected to the lower cutting tool through the cutting tool gear.

[0017] Preferably, the top and bottom of the scissor telescopic structure are provided with a second lifting nut, which is connected to the first lifting nut.

[0018] Preferably, the center of the second upper cover is provided with a reserved hole for the second upper cover, and the center of the second lower cover is provided with a reserved hole for the second lower cover.

[0019] Preferably, the drill rod passes through the reserved holes of the first upper protective cover, the first lower protective cover, the upper reserved hole, the lower reserved hole, and the second upper protective cover, and is connected to the reserved hole of the second lower protective cover via a bearing.

[0020] Preferably, the two ends of the second shaft reducer are connected to the upper reserved hole and the lower reserved hole respectively through the first lifting nut and the second lifting nut.

[0021] The advantages and positive effects of the in-situ shear testing device for soil and rock bodies described in this invention are:

[0022] 1. The device described in this invention facilitates in-situ shear testing in deep soil and rock boreholes.

[0023] 2. This invention can achieve loading tests on the borehole wall rock and soil with different constant radial pressure values ​​along the borehole radial direction.

[0024] 3. This invention can realize loading tests of deep rock and soil masses with different shear rates and different shear pressure values.

[0025] 4. Compared with indoor tests, the device described in this invention can realize the in-situ testing process of simultaneous loading and shearing in the borehole of soil and rock, which can truly reflect the shear strength parameters of the actual soil and rock. Furthermore, the in-situ shear test in the borehole has less disturbance, strong representativeness, and is more in line with the actual engineering situation.

[0026] 5. This invention can realize multi-point in-situ testing at different drilling depths in rock and soil bodies.

[0027] 6. This invention is simple and convenient to operate and produces good test results.

[0028] 7. The device described in this invention is detachable, easy to transport, and reusable.

[0029] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0031] Figure 2 This is a schematic diagram of the axial loading system structure in this invention;

[0032] Figure 3 This is a schematic diagram of the longitudinal cross-sectional structure of the limiting column in this invention;

[0033] Figure 4 This is a schematic diagram of the cutting power system structure in this invention;

[0034] Figure 5 This is a schematic diagram of the rotating system structure in this invention;

[0035] Figure 6 This is a schematic diagram of the upper cutter head control system structure in this invention;

[0036] Figure 7 This is a schematic diagram of the shear testing system structure in this invention;

[0037] Figure 8 This is a schematic diagram of the lower cutter head control system structure in this invention;

[0038] Figure 9 This is a schematic cross-sectional view illustrating the application of the present invention inside a borehole.

[0039] Figure Labels

[0040] 1. Axial loading system; 1-1. Positioning flange; 1-2. Cover plate; 1-3. Connecting plate; 1-4. Limiting post; 1-4-1. Limiting screw; 1-4-2. Spring; 1-5. Downward pressure cylinder; 1-6. Reaction plate; 2. Cutting system; 2-1. Support rod; 2-2. Main cutting motor; 2-3. Lower base plate; 3. Rotation system; 3-1. First shaft diameter reducer; 3-2. Cable routing slip ring; 3-3. Coupling; 3-4. Drill rod; 3-5. Second shaft diameter reducer; 3-6. First lifting nut; 3-7. Bearing; 4. Upper cutter head control system; 4-1. First upper guard reserved hole; 4-2. First upper guard; 4-3. First solenoid valve controller; 4-4. First lower guard reserved hole; 4-5. First drive motor; 4-6. First lower guard; 5. Shearing test system; 5-1, Upper cutter head; 5-2, Upper cutting tool; 5-3, Upper reserved hole; 5-4, Scissor-type telescopic structure; 5-5, Pressure block; 5-6, Rotating shaft; 5-7, Second lifting nut; 5-8, Lower reserved hole; 5-9, Blade rotating shaft; 5-10, Cutting gear; 5-11, Tool gear; 5-12, Solenoid valve control switch; 5-13, Lower cutter head; 5-14, Lower cutting tool; 6, Lower cutter head control system; 6-1, Second upper guard reserved hole; 6-2, Second upper guard; 6-3, Second drive motor; 6-4, Second solenoid valve controller; 6-5, Second lower guard; 6-6, Fixed bracket; 6-7, Second lower guard reserved hole; 7, Drilling hole; 8, Hole wall soil; 9, Upper annular groove; 10, Shearing surface; 11, Lower annular groove. Detailed Implementation

[0041] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0042] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0043] Example

[0044] like Figure 1 As shown, an in-situ shear testing device for soil and rock boreholes includes an axial loading system 1, a cutting power system 2, a rotation system 3, an upper cutter head control system 4, a shear testing system 5, and a lower cutter head control system 6.

[0045] like Figure 2 and Figure 3 As shown, the axial loading system 1 includes a pressing cylinder 1-5, a cover plate 1-2 is provided above the pressing cylinder 1-5, and a reaction plate 1-6 is provided below the pressing cylinder 1-5.

[0046] A positioning flange 1-1 is provided on the upper surface of the cover plate 1-2. A limiting post 1-4 with limiting and unloading / rebound functions is provided between the cover plate 1-2 and the reaction plate 1-6. A limiting screw 1-4-1 and a spring 1-4-2 are provided inside the limiting post 1-4. A connecting plate 1-3 is provided on the outside of the pressing cylinder 1-5. The outer shell of the pressing cylinder 1-5 is connected to the cover plate 1-2 through the connecting plate 1-3. The pull rod end of the pressing cylinder 1-5 is connected to the reaction plate 1-6 by bolts. When the pressing cylinder 1-5 is working, it provides thrust to the reaction plate 1-6. The limiting screw 1-4-1 and the spring 1-4-2 play the roles of limiting and rebound. The cover plate 1-2 and the reaction plate 1-6 are made of high-strength steel plate.

[0047] like Figure 4 As shown, the cutting power system 2 includes a main cutting motor 2-2, which is connected to the lower base plate 2-3 by bolts. Support rods 2-1 are provided around the main cutting motor 2-2, and the two ends of the support rods 2-1 are connected to the reaction plate 1-6 and the lower base plate 2-3, respectively.

[0048] like Figure 5As shown, the rotating system 3 includes a first shaft reducer 3-1, which is connected to the drill rod 3-4 via a coupling 3-3. A second shaft reducer 3-5 is located at the lower part of the drill rod 3-4, and a first lifting nut 3-6 is located on the outside of the second shaft reducer 3-5. A cable routing slip ring 3-2 is sleeved on the outside of the first shaft reducer 3-1 and the coupling 3-3, and a bearing 3-7 is located at the bottom end of the drill rod 3-4.

[0049] like Figure 6 As shown, the upper cutter head control system 4 includes a first solenoid valve controller 4-3, which is connected to a first lower protective cover 4-6 by bolts. A first drive motor 4-5 is mounted on the upper surface of the first lower protective cover 4-6. A first upper protective cover 4-2 is fitted over the first solenoid valve controller 4-3 and the first drive motor 4-5. The first upper protective cover 4-2 and the first lower protective cover 4-6 are used to protect the instrument and prevent damage.

[0050] The center of the first upper protective cover 4-2 is provided with a reserved hole 4-1 for the first upper protective cover, and the center of the first lower protective cover 4-6 is provided with a reserved hole 4-4 for the first lower protective cover.

[0051] like Figure 7 As shown, the shearing test system 5 includes an upper cutting tool 5-2 and a lower cutting tool 5-14. The upper cutting tool 5-2 is connected to the upper cutter head 5-1 via a blade shaft 5-9, and the lower cutting tool 5-14 is connected to the lower cutter head 5-13 via the blade shaft 5-9. The upper cutter head 5-1 has a pre-drilled hole 5-3 at its center. A cutting gear 5-10 is positioned outside the pre-drilled hole 5-3, and a cutting gear 5-11 is positioned outside the cutting gear 5-10. The cutting gear 5-10 is connected to the upper cutting tool 5-2 via the cutting gear 5-11. The lower cutter head 5-13 has a pre-drilled hole 5-8 at its center. A cutting gear 5-10 is positioned outside the pre-drilled hole 5-8, and a cutting gear 5-11 is positioned outside the cutting gear 5-10. The cutting gear 5-10 is connected to the lower cutting tool 5-14 via the cutting gear 5-11. Solenoid valve limit switches 5-12 are also installed on the upper cutter head 5-1 and the lower cutter head 5-13.

[0052] A pressure block 5-5 is provided between the upper cutter head 5-1 and the lower cutter head 5-13. A scissor-type telescopic structure 5-4 is installed inside the pressure block 5-5, and the scissor-type telescopic structure 5-4 is connected to the pressure block 5-5 via a rotating shaft 5-6. The existing structure of the scissor-type telescopic structure 5-4 is selected according to requirements.

[0053] Pressure sensors are installed on the upper cutting tool 5-2, the lower cutting tool 5-14, and the pressure block 5-5, which can respectively collect the shear pressure and radial pressure measured during shearing. The shearing process can be transmitted to the ground in real time, and the real-time curve of shear pressure versus shear displacement can be automatically displayed and saved. The upper cutting tool 5-2, the lower cutting tool 5-14, and the pressure block 5-5 are preferably high-strength steel plates.

[0054] The top and bottom of the scissor telescopic structure 5-4 are both provided with a second lifting nut 5-7, which is connected to the first lifting nut 3-6.

[0055] like Figure 8 As shown, the lower cutter head control system 6 includes a second solenoid valve controller 6-4. Bolts are provided on the upper surface of the second solenoid valve controller 6-4, and a fixing bracket 6-6 is provided on its side. The second solenoid valve controller 6-4 is connected to the second upper protective cover 6-2 via bolts and the fixing bracket 6-6. A second drive motor 6-3 is installed inside the second upper protective cover 6-2, and a second lower protective cover 6-5 is provided below the second upper protective cover 6-2 for protection. The second upper protective cover 6-2 and the second lower protective cover 6-5 are used to protect the instrument and prevent damage.

[0056] The second upper protective cover 6-2 has a reserved hole 6-1 at its center, and the second lower protective cover 6-5 has a reserved hole 6-7 at its center.

[0057] The first drive motor 4-5 is used to open the upper cutting tool 5-2 during cutting, and the first solenoid valve controller 4-3 is used to retract the upper cutting tool 5-2 to its original position; the second drive motor 6-3 is used to open the lower cutting tool 5-14 during cutting, and the second solenoid valve controller 6-4 is used to retract the lower cutting tool 5-14 to its original position.

[0058] like Figure 5-8 As shown, the first shaft reducer 3-1, the cable guide slip ring 3-2, and the coupling 3-3 drive the drill rod 3-4 to rotate. The drill rod 3-4 passes through the first upper guard reserved hole 4-1 and the first lower guard reserved hole 4-4 of the upper cutter head control system 4; the second shaft reducer 3-5 is connected to the upper reserved hole 5-3 and the lower reserved hole 5-8 through the first lifting nut 3-6 and the second lifting nut 5-7; then the drill rod 3-4 passes through the second upper guard reserved hole 6-1 of the lower cutter head control system 6 and is connected to the second lower guard reserved hole 6-7 through the bearing 3-7.

[0059] When a cutting task is required, the first drive motor 4-5 and the second drive motor 6-3 respectively activate the upper cutting tool 5-2 and the lower cutting tool 5-14. At this time, the main cutting motor 2-2 operates, and the drill rod 3-4 drives the second shaft reducer 3-5 to rotate, thereby driving the cutting gear 5-10 and the tool gear 5-11 to rotate, thus driving the upper cutting tool 5-2 and the lower cutting tool 5-14 to complete the cutting task. The rotation of the second shaft reducer 3-5 pushes the pressure block 5-5 on the scissor-type telescopic structure 5-4 through the first lifting nut 3-6 and the second lifting nut 5-7, thereby providing radial pressure. When the cutting task is completed, the main cutting motor 2-2 stops working, and the shearing test system also stops working. The first drive motor 4-5 and the second drive motor 6-3 retract the upper cutting tool 5-2 and the lower cutting tool 5-14. The first solenoid valve controller 4-3 and the second solenoid valve controller 6-4 control the solenoid valve limit switch 5-12 to return the upper cutting tool 5-2 and the lower cutting tool 5-14 to their original positions.

[0060] To conduct in-situ shear testing at single or multiple points within boreholes in soil and rock masses, the following operations are required:

[0061] a. According to Figure 1 As shown, the relevant components are installed; a hole is drilled in the middle of the rock and soil mass using a drilling bit, forming a shape as shown. Figure 9 The geological model shown contains boreholes (circular cross-section);

[0062] b. The positioning flange 1-1 in the axial loading system 1 is fixed with a steel wire rope. During operation, the entire equipment is suspended by the steel wire rope to a predetermined depth A within the borehole 7. Figure 9 As shown;

[0063] c. Establish upper annular groove 9 and lower annular groove 11: (e.g.) Figure 7 As shown, the upper cutter drive motor 4-5 activates the upper cutting cutter 5-2, and the lower cutter drive motor 6-3 activates the lower cutting cutter 5-14; the main cutting motor 2-2 operates, driving the second shaft reducer 3-5 to rotate, and the upper and lower cutters cut the soil to form upper and lower annular grooves, as shown. Figure 9 As shown;

[0064] d. After the upper and lower annular grooves are formed, the second solenoid valve controller 6-4 retracts the lower cutting tool 5-14 to its original position.

[0065] e. Apply shear radial pressure σn: such as Figure 7 and 9As shown, the pressure block 5-5 applies radial pressure σn to the geological model A at a depth of a constant value. The radial pressure value can be controlled at a constant value (such as 50, 100, 150, 200, 300 kPa), and the maximum radial pressure value can reach 400 kPa. The pressure block 5-5 is equipped with a pressure sensor, and the radial pressure value can be displayed in real time.

[0066] f. Apply shear pressure τ: such as Figure 2 As shown, hydraulic cylinder 1-6 pushes reaction plate 1-7 to work, causing... Figure 1 The cutting power system 2, rotation system 3, upper cutter head control system 4, shearing test system 5, and lower cutter head control system 6 are all pushed downwards as a whole. Figure 7 The upper cutter 5-2 provides downward shearing pressure, corresponding to... Figure 9 Geological model A is subjected to a shear pressure τ at a depth (at which point the radial pressure is maintained at a constant value); the upper cutter 5-2 is equipped with a pressure sensor, the shear rate can be controlled at 0.02mm / min, 0.8mm / min, etc., the maximum shear pressure value is 400kPa, and it can be displayed in real time;

[0067] g. The shearing process can display and save the real-time curves of shearing pressure and shearing displacement. When the shearing displacement reaches 42mm, the in-situ shearing test in the hole ends.

[0068] h. To achieve multi-point in-situ shear testing within the borehole, the wire rope can be adjusted to be suspended at different depths, such as points B and C, within borehole 7 (e.g., ...). Figure 9 As shown in the figure, multi-point in-situ shearing test is achieved, and the operation process is as shown in steps c, d, e, f, and g.

[0069] Therefore, the present invention provides an in-situ shear testing device for deep soil and rock bodies with the above-described structure, which solves the problems of difficulty in in-situ shear testing in deep soil and rock bodies, lack of testing devices, difficulty in radial testing, difficulty in simultaneous loading and shearing, and difficulty in multi-point in-situ testing.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An in-situ shear testing device for soil and rock masses, characterized in that: The axial loading system, the cutting power system, the rotating system, the upper cutter control system, the shearing test system and the lower cutter control system are included. The axial loading system includes a down-pressing oil cylinder, and a cover plate is arranged above the down-pressing oil cylinder, and a counterforce plate is arranged below the down-pressing oil cylinder. The cutting power system includes a main cutting motor, and the main cutting motor is connected with the lower bottom plate through bolts. The rotating system includes a first rotating shaft reducer, and the first rotating shaft reducer is connected with a drill rod through a shaft coupling, and a second rotating shaft reducer is arranged at the lower part of the drill rod, and a first lifting nut is arranged outside the second rotating shaft reducer. The upper cutter control system includes a first electromagnetic valve controller, and the first electromagnetic valve controller is connected with the first lower shield through bolts, and a first driving motor is arranged on the upper surface of the first lower shield, and a first upper shield is arranged outside the first electromagnetic valve controller and the first driving motor. The shearing test system includes an upper cutting tool and a lower cutting tool, and the upper cutting tool is connected with an upper cutter through a blade rotating shaft, and the lower cutting tool is connected with a lower cutter through a blade rotating shaft, and a pressing block is arranged between the upper cutter and the lower cutter, and a scissor-type telescopic structure is arranged inside the pressing block, and the scissor-type telescopic structure is connected with the pressing block through a rotating shaft. The lower cutter control system includes a second electromagnetic valve controller, and a bolt is arranged on the upper surface of the second electromagnetic valve controller, and a fixing support is arranged on the side surface of the second electromagnetic valve controller, and the second electromagnetic valve controller is connected with a second upper shield through the bolt and the fixing support, and a second driving motor is arranged inside the second upper shield, and a second lower shield for protection is arranged below the second upper shield. Pressure sensors are arranged on the upper cutting tool, the lower cutting tool and the pressing block. An upper reserved hole is arranged at the center of the upper cutter, a cutting gear is arranged outside the upper reserved hole, a tool gear is arranged outside the cutting gear, and the cutting gear is connected with the upper cutting tool through the tool gear, and a lower reserved hole is arranged at the center of the lower cutter, a cutting gear is arranged outside the lower reserved hole, a tool gear is arranged outside the cutting gear, and the cutting gear is connected with the lower cutting tool through the tool gear.

2. An in-situ shear testing device for use in a geotechnical bore according to claim 1, wherein: A positioning flange is arranged on the upper surface of the cover plate, a limiting column with limiting and unloading rebound functions is arranged between the cover plate and the counterforce plate, a limiting screw and a spring are arranged inside the limiting column, and a connecting plate is arranged outside the down-pressing oil cylinder, and the down-pressing oil cylinder is connected with the cover plate through the connecting plate.

3. The in-situ shear testing device for use in a geotechnical borehole according to claim 1, wherein: Supporting rods are arranged around the main cutting motor, and the two ends of the supporting rods are respectively connected with the counterforce plate and the lower bottom plate.

4. The in-situ shear testing device for use in a geotechnical borehole according to claim 1, wherein: A wire running slip ring is arranged outside the first rotating shaft reducer and the shaft coupling, and a bearing is arranged at the bottom end of the drill rod.

5. The in-situ shear testing device for use in a geotechnical borehole according to claim 1, wherein: A first upper shield reserved hole is arranged at the center of the first upper shield, and a first lower shield reserved hole is arranged at the center of the first lower shield.

6. The in-situ shear testing device for use in a geotechnical borehole according to claim 1, wherein: Second lifting nuts are arranged at the top and the bottom of the scissor-type telescopic structure, and the second lifting nuts are connected with the first lifting nut.

7. The in-situ shear testing device for use in a geotechnical borehole according to claim 1, wherein: A second upper shield reserved hole is arranged at the center of the second upper shield, and a second lower shield reserved hole is arranged at the center of the second lower shield.

8. The in-situ shear testing device for use in a geotechnical hole according to claim 1 or 5 or 7, wherein: The drill rod passes through the first upper shield reserved hole, the first lower shield reserved hole, the upper reserved hole, the lower reserved hole and the second upper shield reserved hole, and is connected with the second lower shield reserved hole through a bearing.

9. The in-situ shear testing device for use in a geotechnical hole according to claim 1 or 6, wherein: Two ends of the second rotating shaft reducer are connected with the upper reserved hole and the lower reserved hole through the first lifting nut and the second lifting nut respectively.

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