A portable in-situ drilling shearing instrument for vegetation cover soil and a method of use thereof

Abstract

The present invention discloses a portable in-situ drilling shearing instrument for vegetation cover soil and a method of use. The in-situ drilling shearing instrument includes a hydraulic pressurizing mechanism, a normal stress loading mechanism, and a rotary shearing mechanism. The hydraulic pressurizing mechanism is used to provide the rotary shearing mechanism with power for rotational torque and vertical force. The normal stress loading mechanism is used to apply normal stress to the soil of the borehole wall. The rotary shearing mechanism includes a force transmission rod, a rotation controller is installed on the top of the force transmission rod, and a shearing probe is installed on the bottom of the force transmission rod. The rotary controller drives the force transmission rod to generate torque, and drives the shearing piece of the shearing probe to extend or contract radially. The movable part can rotate relative to the force transmission rod and can drive the force transmission rod to move axially. The movable part is connected to the output end of the linear drive device. The shearing probe of the present invention can be embedded in the hole wall to a large depth, with little disturbance to the hole wall soil structure, and is not limited by the problem of uneven hole wall, thereby improving portability and operability.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical testing and relates to a portable in-situ drilling shearing instrument for vegetation cover soil and a use method thereof. Background Art

[0002] In the past decade, my country has built a large number of public infrastructure such as railways, highways, hydropower, waterways and ports, accompanied by the production of many artificial soil slopes. How to ensure the long-term stability of these soil slopes is a common problem faced in the operation of the above public infrastructure. Plant ecological protection, as an engineering technology that can take into account both shallow soil reinforcement and ecological environmental beautification, is increasingly used in soil slope protection, among which herbaceous plants are the most widely used. Plant roots are intertwined in the soil and together with the soil form a root-soil complex. When the soil is subjected to external forces, the tension of the roots will limit the deformation of the soil and increase the shear strength of the soil, thereby playing a role in maintaining the stability of the slope. Therefore, it is of great significance to study the shear strength of vegetation-covered soil.

[0003] The test methods for soil shear strength can be divided into indoor tests and in-situ tests. Indoor test methods such as direct shear test and triaxial test can effectively control soil parameters (such as dry density and moisture content) and root parameters (such as root diameter and root content), which is conducive to analyzing the influence of various factors on soil shear strength, but cannot truly reflect the soil structure and root distribution characteristics. In-situ tests can be carried out in the natural position of the soil, which can maintain the original structure, root distribution and stress state of the soil as much as possible, avoiding the above problems of indoor tests. The existing in-situ shear test methods for soil mainly include in-situ direct shear test, cross-plate shear test and borehole shear test, but these methods have many shortcomings when testing the shear strength and indicators of vegetation-covered soil. For example, the in-situ direct shear test requires the excavation of large-scale test pits and trenches, which consumes a lot of manpower and is only suitable for strength testing of surface soil. The cross-plate shear test equipment is simple and easy to operate, but it is only suitable for measuring the undrained shear strength of saturated soft clay with zero internal friction angle. Compared with the previous two methods, the borehole shear test has higher repeatability and wider application. However, due to the short steel teeth and small shear surface, it requires uniform soil and flat hole walls. However, vegetation cover soil contains a large number of roots and is non-homogeneous soil. In addition, the presence of roots and coarse particles cannot ensure the flatness of the hole wall. In addition, since many steel teeth need to penetrate the hole wall before the test, the soil structure will be disturbed. Therefore, in order to accurately determine the shear strength index of soil containing roots, it is necessary to develop an in-situ shear strength test instrument specifically for vegetation cover soil. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a portable in-situ drilling shear instrument for vegetation cover soil. The shear probe can be embedded in the hole wall to a large depth, with little disturbance to the hole wall soil structure and is not limited by the unevenness of the hole wall. The portability and operability are improved, and the problems existing in the prior art are solved.

[0005] Another object of the present invention is to provide a method for using a portable in-situ drilling shearing instrument for vegetation cover soil.

[0006] The technical solution adopted by the present invention is a portable in-situ drilling shearing instrument for vegetation cover soil, comprising:

[0007] A hydraulic pressurizing mechanism, which is used to provide the rotary shearing mechanism with power for rotary torque and vertical force;

[0008] A normal stress loading mechanism, wherein the normal stress loading mechanism is used to apply normal stress to the soil at the borehole wall;

[0009] The rotary shearing mechanism is used to apply a vertical upward shearing force to the soil on the borehole wall;

[0010] The rotary shearing mechanism comprises

[0011] A force transmission rod, wherein the force transmission rod is arranged vertically, a rotation controller is installed on the top of the force transmission rod, a shear probe is installed on the bottom of the force transmission rod, a cam is arranged inside the shear probe, the cam is fixedly connected to the bottom end of the force transmission rod, the rotation controller drives the force transmission rod to generate torque, and the shearing piece of the shearing probe is driven to extend or retract radially through the cam;

[0012] The movable component can rotate relative to the force transmission rod and can drive the force transmission rod to move axially. The movable component is connected to the output end of the linear drive device.

[0013] Furthermore, the movable parts include

[0014] A force sensor, wherein the force sensor is an annular structure, and the inner ring of the force sensor is clamped on the outer wall of the force transmission rod;

[0015] An externally threaded rod, wherein the externally threaded rod is sleeved outside the force transmission rod, the top of the externally threaded rod abuts against the bottom end of the force sensor, and there is no direct contact between the externally threaded rod and the force transmission rod;

[0016] The internal thread component is an annular structure, the annular inner wall of the internal thread component is threadedly connected to the outer wall of the external thread rod, and the internal thread component is connected to the output end of the linear drive device.

[0017] Furthermore, the shear probe comprises

[0018] A cam, wherein the cam is connected to the force transmission rod through a spiral pattern, and a plurality of protrusions are evenly arranged on the circumferential surface in the horizontal direction of the cam;

[0019] A first prefabricated groove, wherein the first prefabricated groove is arranged on a radial extension line of the cam;

[0020] A second prefabricated groove, wherein the second prefabricated groove is arranged on the radial extension line of the cam, the second prefabricated groove is arranged at an interval from the first prefabricated groove, the bottom of the second prefabricated groove is arranged obliquely, and an end of the bottom of the second prefabricated groove away from the cam is flush with the bottom of the first prefabricated groove;

[0021] An upper sliding slice, wherein the upper sliding slice is slidably connected to the first prefabricated groove, the upper sliding slice and the first prefabricated groove are connected via a spring, and a radially arranged push rod is connected to a position of the upper sliding slice corresponding to the protrusion;

[0022] A lower sliding slice, wherein the lower sliding slice is slidably connected in the second prefabricated groove, the lower sliding slice and the second prefabricated groove are connected via a spring, and a radially arranged push rod is connected to a position of the lower sliding slice corresponding to the protrusion;

[0023] The upper sliding slice and the lower sliding slice are arranged at intervals, and when the upper sliding slice and the lower sliding slice are pushed to the maximum extent in the radial direction, a complete circular surface can be formed.

[0024] Furthermore, the linear drive device is an annular jack, the force transmission rod passes through the annular jack, the annular jack is arranged at the bottom of the movable part, provides force along the axial direction for the movable part, and drives the shear probe to move vertically through the force transmission rod.

[0025] Furthermore, the rotation controller includes:

[0026] A circular ring-shaped shell, wherein an arc-shaped hydraulic chamber is installed inside the circular ring-shaped shell, a fixed metal component with a triangular longitudinal section is welded to the inner top of the hydraulic chamber, and the width of the fixed metal component in the radial direction is the same as the width of the hydraulic chamber; the sliding metal component can slide relatively along the inclined surface of the fixed metal component, and the sliding metal component extends out of the hydraulic chamber along the circumferential direction of the rotary controller away from one end of the fixed metal component, and the extended section of the sliding metal component is connected to the hydraulic chamber in a sliding seal;

[0027] A core body, the core body is arranged inside the annular shell, the core body can rotate relative to the annular shell, the circumference of the core body is fixedly connected to the extension section of the sliding metal component, and the bottom end of the core body is connected to the top end of the force transmission rod;

[0028] The baffle is radially installed at the front end of the sliding metal component in the moving direction. The distance between the baffle and the extending section of the sliding metal component is 1 / 4 to 1 / 3 of the circumference of the rotary controller, and is used to limit the moving position of the sliding metal component.

[0029] Furthermore, the hydraulic pressure mechanism includes

[0030] A liquid pressurizer is used to supply hydraulic oil to the hydraulic chamber or the oil pressure chamber of the ring jack through the control end.

[0031] Furthermore, the control terminal includes

[0032] A cylindrical cavity, which is arranged inside the box of the control end, the cylindrical cavity is connected to the outlet end of the liquid pressurizer through an oil guide pipe, and the cylindrical cavity is connected to the hydraulic chamber or the oil pressure chamber of the annular jack through two other oil guide pipes;

[0033] The number of the blocking blocks is two, and the two blocking blocks are arranged on the arc surface of the cylindrical cavity, so that the interface connecting the hydraulic chamber and the oil pressure chamber is located on the same side of the line connecting the two blocking blocks, and the interface connecting the liquid pressurizer is located on the other side of the line connecting the two blocking blocks;

[0034] An oil guide component, wherein the oil guide component is fan-shaped, and the arc surface of the oil guide component is slidably connected to the arc surface between the two blocking blocks and away from the liquid pressurizer;

[0035] A control rod is installed on the axis of the cylindrical cavity, the control rod is fixedly connected to the center of the oil guide component, one end of the control rod extends out of the box body at the control end, and the control rod controls the oil guide component to rotate along the arc surface.

[0036] Furthermore, the normal stress loading mechanism includes

[0037] A flexible airbag, wherein the flexible airbag is annular, the inner wall of the flexible airbag is closely attached to the external threaded rod, is located above the shear probe, and is closely attached to the soil of the hole wall;

[0038] A gas tank, wherein two cavities are arranged in an upper and lower manner, and a sealing screw is provided between the two cavities to control the connection or separation of the two cavities. The two cavities are used to contain two chemical substances that can react to generate gas; a glass plate is provided on the upper cavity to observe the remaining amount of the chemical substances in the cavity; the gas tank is connected to the flexible air bag through a gas pipeline;

[0039] A normal stress controller is installed on a gas pipeline between a gas tank and a flexible airbag and is used to display normal stress; a pressure gauge and a gas valve are provided on the gas pipeline close to the gas tank.

[0040] Furthermore, the liquid pressurizer comprises

[0041] A piston, wherein the bottom of the piston is a cavity, the bottom of the piston is connected to the cavity in a sliding and sealing manner through a rubber ring, and the top of the piston is connected to one end of a pressure rod;

[0042] An oil cylinder, wherein the oil cylinder is connected to one end of the cavity at the bottom of the piston through a one-way valve, and the other end of the cavity is connected to an oil guide pipe through another one-way valve, and the oil guide pipe is connected to the control end;

[0043] The oil return valve is used to control whether the oil cylinder is directly connected to the oil guide pipe.

[0044] A method for using a portable in-situ drilling shearing instrument for vegetation cover soil is specifically carried out in the following steps:

[0045] Step 1: Install and fix the base just above the hole, send the shear probe of the rotary shear mechanism to the shear position along the vertical hole, and place the normal stress loading mechanism on the hole wall soil above the shear probe;

[0046] Step 2: Start the normal stress loading mechanism to apply a normal force to the hole wall soil above the shear probe;

[0047] Step 3: Soil shearing; drive the force transmission rod to generate a rotating torque through the rotary controller, drive the cam inside the shear probe to rotate, and push the shearing piece of the shear probe to extend radially; reset the force sensor reading to zero, start the linear drive device, drive the internal threaded component to move vertically upward, shear the soil, observe the force sensor reading, and measure the maximum tension;

[0048] Step 4: Change the shear position and repeat steps 1 to 3 to measure the maximum tensile stress of the in-situ soil under different normal stresses, and obtain the shear strength of the soil based on the maximum tensile stress.

[0049] The beneficial effects of the present invention are:

[0050] 1. The present invention replaces the original steel tooth shearing module with a torsionally rotating retractable shearing probe. The shearing probe can be embedded in the hole wall to a great depth, with little disturbance to the hole wall soil structure, and is not limited by the unevenness of the hole wall, and can be suitable for vegetation cover soil; combined with a flexible membrane to apply radial pressure to the hole wall, it avoids the rigid pressure module from generating stress concentration on the hole wall soil when the hole wall is uneven, greatly reduces the damage to the integrity of the soil during shearing, and at the same time increases the embedding depth of the soil, thereby improving the accuracy of the test results.

[0051] 2. The present invention can adjust the depth of the force transmission rod extending into the drilled hole, and perform multiple shear position tests in one hole, thereby improving the test efficiency and accuracy.

[0052] 3. The present invention reduces the overall size and weight of the instrument by optimizing the structures of the shearing probe, the loading device and the base, thereby improving the portability and operability of the drilling shearing instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 The figure is a general structural diagram of a portable drilling and shearing instrument according to an embodiment of the present invention.

[0055] Figure 2 It is a structural diagram of the hydraulic pressurizing mechanism of an embodiment of the present invention.

[0056] Figure 3 This is a cross-sectional view of a liquid pressurizer of a portable drilling shearing instrument according to an embodiment of the present invention.

[0057] Figure 4 It is a schematic cross-sectional view of the control end of the portable drilling and shearing instrument according to an embodiment of the present invention.

[0058] Figure 5 It is a top view schematic diagram of a portable drilling and shearing instrument rotation controller according to an embodiment of the present invention.

[0059] Figure 6 It is a side view of a rotary controller of a portable drilling and shearing machine according to an embodiment of the present invention.

[0060] Figure 7 It is a schematic diagram of the top surface of the base of the portable drilling and shearing instrument according to an embodiment of the present invention.

[0061] Figure 8 It is a side schematic diagram of the base of the portable drilling and shearing instrument according to an embodiment of the present invention.

[0062] Fig. 9 This is a structural diagram of the normal stress loading mechanism of the portable drilling shearing instrument according to an embodiment of the present invention.

[0063] Fig.10 This is a structural diagram of the rotary shearing mechanism of a portable drilling shearing instrument according to an embodiment of the present invention.

[0064] Fig.11 It is a schematic diagram of the retracted top surface of the shear probe of the portable drilling shearing instrument according to an embodiment of the present invention.

[0065] Fig.12 It is a schematic side view of the retracted shearing probe of the portable drilling shearing instrument according to an embodiment of the present invention.

[0066] Fig.13 This is a schematic diagram of the unfolded top surface of the shearing probe of the portable drilling shearing instrument according to an embodiment of the present invention.

[0067] Fig.14 It is a schematic side view of the unfolded shearing probe of the portable drilling shearing instrument according to an embodiment of the present invention.

[0068] Fig.15a Schematic diagram of the structure of a traditional sawtooth probe.

[0069] Fig.15b Schematic diagram of the structure of the shear probe in an embodiment of the present invention.

[0070] In the figure, 1. hydraulic pressure mechanism, 2. normal stress loading mechanism, 3. rotary shear mechanism, 4. liquid pressurizer, 5. pressure rod, 6. oil cylinder, 7. piston, 8. one-way valve, 9. oil return valve, 10. control end, 11. control rod, 12. blocking block, 13. oil guide component, 14. base, 15. rotary controller, 16. annular jack, 17. oil pressure chamber, 18. metal lifting component, 19. hydraulic chamber, 20. sliding metal component, 21. fixed metal component, 22. baffle, 23. . Reserved groove, 24. Oil guide pipe, 25. Fixing screw, 26. Fixing rod, 27. Normal stress controller, 28. Gas tank, 29. Pressure gauge, 30. Gas valve, 31. Glass plate, 32. Solution cavity A, 33 Solution cavity B, 34. Sealing screw, 35. Gas pipeline, 36. Flexible airbag, 37. Force sensor, 38. External thread rod, 39. Force transmission rod, 40. Internal thread component, 41. Shear probe, 42. Cam, 43-1. First prefabricated groove, 43-2. ​​Second prefabricated groove, 44. Upper sliding slice, 45. Lower sliding slice, 46. Push rod, 47. Fastener. DETAILED DESCRIPTION

[0071] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0072] Embodiment 1,

[0073] A portable in-situ drilling shearing instrument for vegetated soil, such as Figure 1 As shown, it includes: a hydraulic pressurizing mechanism 1, a normal stress loading mechanism 2 and a rotary shearing mechanism 3; the hydraulic pressurizing mechanism 1 provides rotary torsion and vertical shearing force for the rotary shearing mechanism 3.

[0074] like Figure 2 As shown, the hydraulic pressurizing mechanism 1 includes a liquid pressurizer 4 , a control end 10 , a base 14 , a rotation controller 15 , an annular jack 16 and an oil guide pipe 24 .

[0075] The annular jack 16 is used to allow the force transfer rod 39 to pass through and provide an upward pulling force for the internal threaded component 40, thereby driving the force transfer rod 39 to move upward; the dimensions of the annular jack 16 are an outer ring diameter of 150 mm, an inner ring diameter of 35 mm, and a height of 55 mm.

[0076] The liquid pressurizer 4 and the annular jack 16 are matching equipment. A pressure rod 5, a cylinder 6, a piston 7, a one-way valve 8 and an oil return valve 9 are arranged inside the liquid pressurizer 4.

[0077] The cross-sectional diagram of the liquid pressurizer 4 is as follows Figure 3 As shown, the pressure rod 5 is connected to the top of the piston 7, and the oil in the oil cylinder 6 is connected to one end of the oil guide pipe 24 through a one-way valve 8; specifically, the bottom of the piston 7 is a cavity, the oil cylinder 6 is connected to one end of the cavity through a one-way valve 8, and the other end of the cavity is connected to the oil guide pipe 24 through another one-way valve 8. The piston 7 is connected to the cavity through a rubber ring at the bottom. When the piston 7 moves downward and compresses the oil in the cavity, the rubber ring can prevent the oil from gushing upward, and the one-way valve 8 prevents the oil from flowing back, so that the oil enters the oil guide pipe 24.

[0078] The oil return valve 9 controls whether the oil cylinder 6 is directly connected to the oil guide pipe 24; a cylindrical cavity is provided inside the box of the control end 10, and the other end of the oil guide pipe 24 is connected to the cylindrical cavity inside the control end 10, and the cylindrical cavity inside the control end 10 is respectively connected to the rotation controller 15 and the annular jack 16 through two other oil guide pipes 24.

[0079] like Figure 4 As shown, two blocking blocks 12 are provided on the arc surface, so that the interface connecting the rotation controller 15 and the annular jack 16 is located on the same side of the line connecting the two blocking blocks 12, and the interface connecting the oil cylinder 6 is located on the other side of the line connecting the two blocking blocks 12, and a fan-shaped oil guiding component 13 is slidably connected on the arc surface of the cylindrical cavity between the two blocking blocks 12 and away from the oil cylinder 6, and the blocking blocks 12 are used to control the moving range of the oil guiding component 13; a control rod 11 is provided on the axis of the cylindrical cavity, one end of the control rod 11 extends out of the box body of the control end 10, and the other end of the control rod 11 is fixedly connected to the center of the oil guiding component 13; the control rod 11 controls the rotation of the oil guiding component 13, and when the oil guiding component 13 is sealed and connected to the interface of the rotation controller 15, the oil in the cylindrical cavity enters the annular jack 16; if the interface is sealed and connected to the annular jack 16, the oil in the cylindrical cavity enters the rotation controller 15, thereby controlling the flow direction of the liquid.

[0080] An oil pressure chamber 17 and a metal lifting component 18 are provided inside the annular jack 16. The metal lifting component 18 is an annular column. The force transmission rod 39 passes through the center of the metal lifting component 18. The metal lifting component 18 is placed in the center of the oil pressure chamber 17. The height of the metal lifting component 18 is lower than the height of the oil pressure chamber 17. The metal lifting component 18 is sealed and slidably connected to the oil pressure chamber 17. The cylindrical cavity inside the control end 10 is connected to the oil pressure chamber 17 through the oil guide pipe 24. The metal lifting component 18 is controlled to move up and down by oil pressure, providing an upward force for the internal threaded component 40.

[0081] In some embodiments, the oil pressure chamber 17 is arranged on the outside of the metal lifting component 18, and is divided into a large cavity and a small cavity. The large cavity is used to store oil, and the function of the small cavity is: to add oil to the oil pressure chamber 17 when in use. According to Pascal's law, the oil pressure is equal everywhere, and F (force) = P (oil pressure) × A (force area). The area of ​​the small cavity is small, while the area of ​​the metal lifting component 18 is large, that is, the large force F can better help the lifting component to rise.

[0082] The rotation controller 15 is connected to the force transmission rod 39 and is used to apply torque to the force transmission rod 39. The internal structure of the rotation controller 15 is as follows: Figure 5 , 6 As shown, a hydraulic chamber 19, a sliding metal component 20, a fixed metal component 21, and a baffle 22 are provided.

[0083] The core of the rotary controller 15 is arranged inside the annular shell, and the core can rotate relative to the annular shell. An arc-shaped hydraulic chamber 19 is installed inside the annular shell, and the arc length is 1 / 4~1 / 3 of the circumference of the rotary controller 15. A fixed metal component 21 with a triangular longitudinal section is welded to the inner top of the hydraulic chamber 19, and the radial width of the fixed metal component 21 is the same as the width of the hydraulic chamber 19; the angle range between the inclined surface of the fixed metal component 21 and the horizontal direction is 5-8°, the thickness of the rotary controller 15 itself is 10mm, and the height of the fixed metal component 21 can only be lower, assuming the height is 5-8mm and the length is 159mm. The sliding metal component 20 can slide relatively along the inclined surface of the fixed metal component 21. The sliding metal component 20 extends a hydraulic chamber 19 along the circumference of the rotation controller 15 away from one end of the fixed metal component 21. The extended section of the sliding metal component 20 is slidingly and sealedly connected to the hydraulic chamber 19; the circumference of the core body is fixedly connected to the extended section of the sliding metal component 20, the bottom end of the core body is connected to the top end of the force transmission rod 39, the baffle 22 is radially installed at the front end of the movement direction of the sliding metal component 20, and the distance between the baffle 22 and the extended section of the sliding metal component 20 is 1 / 4~1 / 3 of the circumference of the rotation controller 15, which is used to limit the moving position of the sliding metal component 20.

[0084] When the pressurized oil enters the hydraulic chamber 19 , the oil pressure pushes the sliding metal component 20 to slide relative to the inclined surface of the fixed metal component 21 , that is, it moves upward while moving forward along the circumference of the rotation controller 15 , thereby pushing the core body to rotate circumferentially and applying torque to the force transmission rod 39 .

[0085] like Figure 7 , 8 As shown, a base 14 is installed at the bottom of the annular jack 16. The circular hole of the base 14 is coaxial with the middle hole of the annular jack 16. A reserved groove 23, fixing screws 25 and a fixing rod 26 are provided on the base 14. The reserved groove 23 is used to place a gas pipeline 35 to ensure the circulation of gas. The fixing screws 25 and the fixing rod 26 are used to fix the base 14 after paving to prevent it from displacement.

[0086] The normal stress loading mechanism 2 applies normal stress to the soil on the borehole wall, such as Fig. 9 As shown, it includes a normal stress controller 27, a gas tank 28, a pressure gauge 29, a gas valve 30, a glass plate 31, a solution chamber A 32, a solution chamber B 33, a sealing screw 34, a gas pipeline 35 and a flexible air bag 36.

[0087] A solution chamber A32 for holding Al2(SO4)3 solution and a solution chamber B33 for holding NaHCO4 solution are provided inside the gas tank 28; a sealing screw 34 is provided at the bottom of the solution chamber A32, and the rotating sealing screw 34 can control the Al2(SO4)3 solution to flow from the solution chamber A32 into the solution chamber B33 and mix with the NaHCO4 solution to generate CO2 gas by chemical reaction; a pressure gauge 29 and a gas valve 30 are provided at the top of the gas tank 28; the reaction principle is as follows:

[0088] (Al2(SO4)3+6NaHCO3==3Na2SO4+2Al(OH)3↓+6CO2↑,

[0089] The theoretical gas production is determined according to the given compound amount in the national standard. A glass plate 31 is provided on the upper part of the gas tank 28. The glass plate has a scale to display the theoretical gas production. The solution content in the solution cavity A32 can be observed. The gas tank 28 is connected to the gas pipeline 35 through the pressure gauge 29 and the gas valve 30, and is connected to the normal stress controller 27 through the gas pipeline 35. The normal pressure controller 27 is connected to the flexible airbag 36 through the gas pipeline 35. The inner wall of the flexible airbag 36 is tightly attached to the external threaded rod 38, and slides down to the bottom of the external threaded rod 38 until it is above the shear probe 41. The normal stress controller 27 plays the role of displaying the normal stress in the embodiment of the present invention.

[0090] The rotary shear mechanism 3 applies a vertical upward shear force to the soil on the borehole wall. Fig.10As shown, it includes a force sensor 37, an external threaded rod 38, a force transmission rod 39, an internal threaded component 40, a shear probe 41 and a fastener 47.

[0091] The top of the force transmission rod 39 is connected to the rotation controller 15, and the bottom of the force transmission rod 39 is connected to the cam 42 of the shear probe 41; the force sensor 37 is an annular structure, and a fastener 47 is installed on the top of the force sensor 37. The inner ring of the force sensor 37 is clamped on the outer wall of the middle and upper part of the force transmission rod 39 by the fastener 47. The external threaded rod 38 is sleeved on the outside of the force transmission rod 39, and the top of the external threaded rod 38 abuts against the bottom end of the force sensor 37, and there is no direct contact between the external threaded rod 38 and the force transmission rod 39; the internal threaded component 40 is an annular structure, and the annular inner wall of the internal threaded component 40 is threadedly connected to the outer wall of the external threaded rod 38, and the internal threaded component 40 is placed on the upper part of the annular jack 16; by adjusting the position of the internal threaded component 40 on the external threaded rod 38, the depth of the force transmission rod 39 extending into the borehole can be adjusted, and tests of different shear positions can be carried out at one hole position. When the metal lifting component 18 provides an upward force, the force transmission rod 39 is driven to produce axial movement through the internal thread component 40, the metal lifting component 18, and the force sensor 37. When the rotation controller 15 drives the force transmission rod 39 to twist, the force transmission rod 39 and the force sensor 37 rotate relative to the external thread rod 38.

[0092] When the shear probe 41 is contracted, the interior Fig.11 , 12 As shown, when expanded Fig.13 , 14As shown, the shearing probe 41 includes a cam 42, a first prefabricated groove 43-1, a second prefabricated groove 43-2, an upper sliding slice 44, and a lower sliding slice 45. The cam 42 is connected to the force transmission rod 39 through a spiral pattern, and a plurality of protrusions are evenly arranged on the circumferential surface of the cam 42 in the horizontal direction; the first prefabricated groove 43-1 is arranged on the radial extension line of the cam 42; the second prefabricated groove 43-2 is arranged on the radial extension line of the cam 42, the second prefabricated groove 43-2 is arranged at intervals from the first prefabricated groove 43-1, the bottom of the second prefabricated groove 43-2 is inclined, and the end of the bottom of the second prefabricated groove 43-2 away from the cam 42 is flush with the bottom of the first prefabricated groove 43-1; the upper sliding slice 44 is connected to the force transmission rod 39 through a spiral pattern, and a plurality of protrusions are evenly arranged on the circumferential surface of the cam 42 in the horizontal direction; the first prefabricated groove 43-1 is arranged on the radial extension line of the cam 42; the second prefabricated groove 43-2 is arranged at intervals from the first prefabricated groove 43-1, and the bottom of the second prefabricated groove 43-2 is inclined, and the end of the bottom of the second prefabricated groove 43-2 away from the cam 42 is flush with the bottom of the first prefabricated groove 43-1; The movable slice 44 is slidably connected in the first prefabricated groove 43-1, the upper sliding slice 44 is connected to the first prefabricated groove 43-1 by a spring, and the position of the upper sliding slice 44 corresponding to the protrusion is connected with a radially arranged push rod 46; the lower sliding slice 45 is slidably connected in the second prefabricated groove 43-2, the lower sliding slice 45 is connected to the second prefabricated groove 43-2 by a spring, and the position of the lower sliding slice 45 corresponding to the protrusion is connected with a radially arranged push rod 46; wherein, the upper sliding slice 44 and the lower sliding slice 45 are spaced apart, and when the upper sliding slice 44 and the lower sliding slice 45 are pushed radially to the maximum extent, a complete circular surface can be formed.

[0093] The dimensions of the rotation controller 15 are: 50mm in diameter and 10mm in height; the normal stress controller 27 can adopt the Biaozhi GM520 differential pressure controller produced by Shenzhen Jumaoyuan Technology Co., Ltd., with a measuring range of ±35kPa and an accuracy of ±0.3%. The dimensions are 170mm in length, 75mm in width and 35mm in height; the force sensor 37 can adopt the LFC-34 type reinforced cylindrical force sensor produced by Shenzhen Juli Sensing Technology Co., Ltd., with a measuring range of 0~3kN and a dimension of 35mm in inner ring diameter, which can be customized; the specific mass of the solution in the solution cavity A32 in the gas tank 28 is 3600g of Al2(SO4) and 1000ml of clean water, the specific mass of the solution in the solution cavity B33 is 430g of NaHCO4 and 4500ml of clean water, and the glass plate 31 is provided with a plurality of support columns, each of which has a measuring range of 0~3kN and a measuring range of 0~3kN and a measuring range of 35mm in inner ring diameter, which can be customized; the specific mass of the solution in the solution cavity A32 in the gas tank 28 is 3600g of Al2(SO4) and 1000ml of clean water, and the specific mass of the solution in the solution cavity B33 is 430g of NaHCO4 and 4500ml of clean water. The highest scale is 114L; the force transmission rod 39 has a diameter of 35mm and a height of 1.5m~2.5m; the inner spiral component 40 has an outer ring diameter of 70mm, an inner ring diameter of 36mm, and a height of 70mm; the annular jack 16 has an outer ring diameter of 150mm, an inner ring diameter of 36mm, and a height of 55mm; the base 14 has a length of 500mm, a width of 150mm, and a middle hole diameter of 82mm; the shear probe 41 has a diameter of 80mm when retracted; the shear probe 41 has a diameter of 90mm when fully extended; the fastener 47 can be a single buckle with a diameter of 30-35 produced by Guangzhou Juyuxin Machinery Equipment Co., Ltd., with an inner ring diameter of 35mm, and is fixed with two nuts to ensure the stable application of axial force. The model of the force sensor 37 is LFC-34.

[0094] Embodiment 2,

[0095] A method for using a portable in-situ drilling shearing instrument for vegetation cover soil is specifically carried out in the following steps:

[0096] Step 1: The base 14 is installed and fixed just above the hole, and the shear probe 41 of the rotary shear mechanism 3 is sent to the shear position along the vertical hole, and the normal stress loading mechanism 2 is placed on the hole wall soil above the shear probe 41;

[0097] Step 2: Start the normal stress loading mechanism 2 to apply a normal force to the hole wall soil above the shear probe 41;

[0098] Step 3: soil shearing; drive the force transmission rod 39 to generate rotational torque by rotating the controller 15, drive the cam 42 inside the shear probe 41 to rotate, and push the shearing piece of the shear probe 41 to extend radially; install the fastener 47 on the top of the force sensor 37, then reset the force sensor 37 to zero, start the linear drive device, drive the internal threaded component 40 to move vertically upward, shear the soil, observe the force sensor 37 reading, and measure the maximum tension.

[0099] Step 4: Change the shear position and repeat steps 1 to 3 to measure the maximum tensile stress of the in-situ soil under different normal stresses, and obtain the shear strength of the soil based on the maximum tensile stress.

[0100] Embodiment 3,

[0101] When the portable in-situ borehole shear tester for vegetation cover soil is used to test the shear strength of soil by multiple shearing in the same borehole, the specific operation steps are as follows:

[0102] Step S1: Instrument Installation

[0103] Step S1-1: Drill holes and lay the base 14. At 0.25m 2 Drill a vertical hole with a diameter of 80 mm and a depth of 3 m on the flat ground, splice the base 14 just above the hole, align the fixing rod 26 with the hole on the base 14, tighten the fixing screws 25 on both sides, and perform the same operation on the fixing screws 25 and fixing rod 26 on the other side.

[0104] Step S1-2: Rod assembly. Install the shear probe 41 at the bottom of the force transmission rod 39, and then move the external threaded rod 38 downward from the top of the force transmission rod 39. The top of the external threaded rod 38 is clamped and fixed to the upper middle part of the force transmission rod 39 by the force sensor 37. Fix the flexible airbag 36 to the bottom of the external threaded rod 38 and the top of the shear probe 41. The flexible airbag 36 is connected to the normal stress controller 27 through the gas pipeline 35. The gas pipeline 35 is placed in the reserved groove 23 on the base 14.

[0105] Step S1-3: Determine the shearing position. Deliver the shearing probe 41 to the required shearing position along the vertical hole, fix the force transmission rod 39 and place the annular jack 16 from the top until the annular jack 16 contacts the base 14, and the annular jack 16 is connected to the control end 10 through the oil guide pipe 24. Move the internal threaded component 40 from the top of the force transmission rod 39 to the top of the external threaded rod 38, and then rotate the internal threaded component 40 to slide it to the top of the annular jack 16. Fix the rotation controller 15 at the top of the force transmission rod 39 and connect it to the control end 10 through the oil guide pipe 24.

[0106] Step S2: Apply normal force. After the gas tank 28 is connected to the normal stress controller 27 through the gas pipeline 35, the sealing screw 34 is loosened to allow the Al2(SO4)3 solution in the solution chamber A32 to flow out through the hole and react with the NaHCO4 solution in the solution chamber B33 at the bottom of the gas tank 28 to generate a large amount of CO2 gas. Observe the pressure gauge 29 and the glass plate 31 to check the amount of gas generated. After sufficient gas is generated, tighten the sealing screw 34, open the gas valve 30 of the gas tank 28, allow the gas to enter the normal stress controller 27, observe the reading (air pressure) of the normal stress controller 27, and at the same time, introduce the CO2 gas into the flexible airbag 36 to make it close to the soil and apply normal stress, that is, perpendicular to the hole wall of the vertical hole.

[0107] Step S3: Soil shearing. The liquid pressurizer 4 is connected to the control end 10 with the oil guide pipe 24, and the oil return valve 9 is turned to block the connection between the oil cylinder 6 and the oil guide pipe 24. The control rod 11 is pulled downward to make the oil guide component 13 block the pipe leading to the annular jack 16, that is, the oil guide pipe 24 is connected to the hydraulic chamber 19 in the rotary controller 15. The control rod 11 is pulled downward to make the oil guide component 13 block the pipe leading to the annular jack 16, which means that the hydraulic chamber 19 in the rotary controller 15 is connected to the liquid pressurizer 4 through the oil guide pipe 24. Repeatedly press the pressure rod 5 of the liquid pressurizer 4, so that the pressure rod 5 drives the piston 7 to continuously press the oil into the oil guide pipe 24 through the one-way valve 8. At the same time, the oil in the oil cylinder 6 fills the gap through the one-way valve 8. After continuous pressurization, the hydraulic pressure is transmitted to the hydraulic chamber 19. Since the liquid pressure is equal everywhere, the oil pressure pushes the sliding metal part 20 to slide upward. Due to the inclined surface of the fixed metal component 21, a rotating torque is generated, which is transmitted to the cam 42 through the force transmission rod 39, so that the cam 42 rotates and pushes the push rod 46 to slide the upper sliding slice 44 and the lower sliding slice 45. The lower sliding slice 45 slides along the second prefabricated groove 43-2 and finally reaches the same height as the upper sliding slice 44 to form a complete circular surface. First, the force sensor 37 reading is reset to zero, and then the fastener 47 is fixed above the force sensor 37. Finally, the control rod 11 is pulled downward to connect the oil guide pipe 24 to the oil pressure chamber 17 in the annular jack 16, and the pressure rod 5 of the liquid pressurizer 4 is repeatedly pressed to make the metal lifting component 18 rise. At the same time, the reading of the force sensor 37 is observed to measure the maximum tension. The shearing process does not need to test the size of the torque, and the values ​​(tension, confining pressure) that need to be tested in detail during the shearing process are all independent of the torsion, which can ensure the accuracy of the test.

[0108] Step S4: end of the test;

[0109] Step S4-1: Component reset. After the soil shearing is completed, turn the oil return valve 9 to connect the oil cylinder 6 to the oil guide pipe 24, observe that the metal lifting component 18 is reset, and turn the oil return valve 9. Pull the control lever 11 upward, turn the oil return valve 9 again, observe that the rotation controller 15 is reset, and then turn the oil return valve 9. Tighten the gas valve 30 of the gas tank 28, remove the normal stress controller 27 and the flexible airbag 36 and the gas pipe 35 of the gas tank 28, and squeeze the flexible airbag 36 to release the gas. Remove the oil guide pipe 24 connecting the control end 10 to the annular jack 16 and the rotation controller 15, and then remove the rotation controller 15, the internal thread component 40 and the annular jack 16 in turn.

[0110] Step S4-2: Obtain parameters. Change the shear depth in the same borehole. The shear depth should be from shallow to deep. The first shear position is the shallowest. Repeat steps S1-3 to S4-1 to measure the maximum tensile stress of the soil at different depths in the original borehole under different normal stresses. The shear strength of the soil is calculated from the maximum tensile stress. The Mohr circle and strength envelope are drawn to obtain the basic parameters of the rooted soil and reveal the relevant mechanism.

[0111] Embodiment 4,

[0112] refer to Figure 1-14 When the portable in-situ borehole shear tester for vegetation cover soil is used to test the shear strength of the soil at the same depth in multiple boreholes, the operating steps are as follows:

[0113] Step S1: Instrument Installation

[0114] Step S1-1: Rod assembly. Install the shear probe 41 at the bottom of the force transmission rod 39 through a thread, then move the external threaded rod 38 downward from the top of the force transmission rod 39 until the bottom of the external threaded rod 38 contacts the top of the shear probe 41, the top of the external threaded rod 38 is clamped and fixed to the upper middle part of the force transmission rod 39 by the force sensor 37, and a fastener 47 is installed above the force sensor 37. Fix the flexible airbag 36 to the bottom of the external threaded rod 38 and the top of the shear probe 41, the flexible airbag 36 is connected to the normal stress controller 27 through the gas pipeline 35, and the gas pipeline 35 is placed in the reserved groove 23 on the base 14;

[0115] Step S1-2: Drill holes and lay the base 14. 2 Drill multiple vertical holes with a diameter of 80 mm and a depth of 3 m on the flat ground, splice the base 14 and place it directly above the corresponding holes in the order of shearing, align the fixing rod 26 with the holes on the base 14, tighten the fixing screws 25 on both sides, and perform the same operation on the fixing screws 25 and fixing rod 26 on the other side;

[0116] Steps S1-3 to S4-1 are consistent with the use of the in-situ borehole shear tester when testing the shear strength of soil by multiple shearing in the same borehole;

[0117] Step S4-2: Obtain parameters. Repeat steps S1-3 to S4-1, and measure the maximum tensile stress of soil at the same depth in different boreholes under different normal stresses in different boreholes. Calculate the shear strength of the soil from the maximum tensile stress, draw the Mohr circle and strength envelope, and obtain the basic parameters of the rooted soil to reveal the relevant mechanism.

[0118] The existing sawtooth probe embeds the saw teeth into the soil when shearing the soil, and then lifts the probe upward after applying pressure mechanically. Since the contact area between the sawtooth probe and the soil is large, a large number of saw teeth embedded in the soil will cause significant disturbance to the soil. The present invention adopts a small telescopic probe (the contracted diameter is 80mm, and the expanded diameter is 90mm) and is equipped with a flexible airbag. Before shearing the soil, it is only necessary to embed the telescopic shearing piece into the soil. Four pieces can be spliced ​​into a circular cone-shaped telescopic shearing piece with an outer diameter of 90mm, and 10mm is embedded when fully expanded; and uniform pressure is applied to the soil through the flexible airbag. Finally, the shearing probe is lifted upward by 0~50mm, which causes less disturbance to the soil.

[0119] Existing drilling shearing instruments (patents CN201821754077.8 and CN202020211128.3) all use sawtooth probes. During shearing, the 2.5mm shear teeth must be embedded into the soil, and then tensile stress is applied upward. Therefore, the integrity of the soil is greatly damaged during shearing. Since the steel teeth of the original shearing probe are short and the shearing surface is small, the soil is required to be uniform and the hole wall is flat. However, the vegetation cover soil contains a large number of roots and is non-homogeneous soil. In addition, due to the presence of roots and coarse particles, it is impossible to ensure that the hole wall is flat. Fig.15a As shown in the figure, under the same hole wall situation, the saw teeth of the sawtooth probe have touched the uneven part of the hole wall. At this time, the shear position is not completed and the normal stress can only continue to increase, which will inevitably lead to stress concentration and destroy the integrity of the soil.

[0120] The embodiment of the present invention designs a shear probe 41 with a specific structure, such as Fig.15b As shown, it needs to be fully unfolded during shearing. After unfolding, the 10mm conical iron sheet is embedded in the soil, and then tensile stress is applied upward; and a flexible airbag 36 is adopted to wrap the uneven soil, so that the normal stress is more evenly distributed on the soil, avoiding stress concentration, greatly reducing the damage to the integrity of the soil during shearing, and at the same time increasing the embedding depth in the soil, thereby improving the accuracy of the test results; in addition, the overall components of the embodiment of the present invention are small in size and weight, and can be carried and transported by two people.

[0121] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A portable in-situ drilling shearing instrument for vegetation cover soil, characterized in that: include: A hydraulic pressurizing mechanism (1), wherein the hydraulic pressurizing mechanism (1) is used to provide rotational torque and vertical force to the rotary shearing mechanism (3); A normal stress loading mechanism (2), wherein the normal stress loading mechanism (2) is used to apply normal stress to the soil at the borehole wall; The rotary shearing mechanism (3) is used to apply a vertical upward shearing force to the soil at the wall of the drill hole; The rotary shearing mechanism (3) comprises A force transmission rod (39), wherein the force transmission rod (39) is arranged vertically, a rotation controller (15) is installed on the top of the force transmission rod (39), a shear probe (41) is installed on the bottom of the force transmission rod (39), a cam (42) is provided inside the shear probe (41), and the cam (42) is fixedly connected to the bottom end of the force transmission rod (39), the rotation controller (15) drives the force transmission rod (39) to generate a torque, and the cam (42) drives the shearing piece of the shearing probe (41) to radially extend or retract; A movable component, wherein the movable component and the force transmission rod (39) can rotate relative to each other and can drive the force transmission rod (39) to move axially, and the movable component is connected to the output end of the linear drive device; The shear probe (41) comprises A cam (42), wherein the cam (42) is connected to the force transmission rod (39) via a spiral pattern, and a plurality of protrusions are evenly arranged on a circumferential surface in a horizontal direction of the cam (42); A first prefabricated groove (43-1), wherein the first prefabricated groove (43-1) is arranged on a radial extension line of the cam (42); a second preformed groove (43-2), the second preformed groove (43-2) being arranged on a radial extension line of the cam (42), the second preformed groove (43-2) being spaced apart from the first preformed groove (43-1), the bottom of the second preformed groove (43-2) being arranged obliquely, and an end of the bottom of the second preformed groove (43-2) away from the cam (42) being flush with the bottom of the first preformed groove (43-1); An upper sliding slice (44), the upper sliding slice (44) being slidably connected in the first prefabricated groove (43-1), the upper sliding slice (44) and the first prefabricated groove (43-1) being connected via a spring, and a radially arranged push rod (46) being connected to a position of the upper sliding slice (44) corresponding to the protrusion; A lower sliding slice (45), the lower sliding slice (45) being slidably connected in the second prefabricated groove (43-2), the lower sliding slice (45) and the second prefabricated groove (43-2) being connected via a spring, and a radially arranged push rod (46) being connected to a position of the lower sliding slice (45) corresponding to the protrusion; The upper sliding slice (44) and the lower sliding slice (45) are arranged at intervals, and when the upper sliding slice (44) and the lower sliding slice (45) are pushed to the maximum extent in the radial direction, a complete circular surface can be formed.

2. A portable in-situ drilling shearing instrument for vegetation cover soil according to claim 1, characterized in that: The movable parts include A force sensor (37), wherein the force sensor (37) is an annular structure, and an inner ring of the force sensor (37) is clamped on an outer wall of the force transmission rod (39); An externally threaded rod (38), wherein the externally threaded rod (38) is sleeved on the outside of the force transmission rod (39), the top of the externally threaded rod (38) abuts against the bottom end of the force sensor (37), and the externally threaded rod (38) and the force transmission rod (39) are not in direct contact; The internal thread component (40) is an annular structure, the annular inner wall of the internal thread component (40) is threadedly connected to the outer wall of the external thread rod (38), and the internal thread component (40) is connected to the output end of the linear drive device.

3. A portable in-situ drilling shearing instrument for vegetation cover soil according to claim 1, characterized in that: The linear drive device is an annular jack (16), a force transmission rod (39) passes through the annular jack (16), and the annular jack (16) is arranged at the bottom of the movable part to provide a force along the axial direction for the movable part, thereby driving the shear probe (41) to move vertically through the force transmission rod (39).

4. A portable in-situ drilling shearing instrument for vegetation cover soil according to claim 1, characterized in that: The rotation controller (15) comprises: A circular ring shell, wherein an arc-shaped hydraulic chamber (19) is installed inside the circular ring shell, a fixed metal component (21) with a triangular longitudinal section is welded to the inner top of the hydraulic chamber (19), and the width of the fixed metal component (21) in the radial direction is the same as the width of the hydraulic chamber (19); the sliding metal component (20) can slide relatively along the inclined surface of the fixed metal component (21), and the sliding metal component (20) extends out of the hydraulic chamber (19) along the circumferential direction of the rotary controller (15) away from one end of the fixed metal component (21), and the extended section of the sliding metal component (20) is connected to the hydraulic chamber (19) in a sliding and sealing manner; A core body, the core body being arranged inside the annular shell, the core body being able to rotate relative to the annular shell, the circumference of the core body being fixedly connected to an extension section of the sliding metal component (20), and the bottom end of the core body being connected to the top end of the force transmission rod (39); A baffle (22) is radially mounted at the front end of the sliding metal component (20) in the moving direction, and the distance between the baffle (22) and the extended section of the sliding metal component (20) is 1 / 4 to 1 / 3 of the circumference of the rotary controller (15), and is used to limit the moving position of the sliding metal component (20).

5. A portable in-situ drilling shearing instrument for vegetation cover soil according to claim 3 or 4, characterized in that: The hydraulic pressure mechanism (1) comprises The liquid pressurizer (4) is used to supply hydraulic oil to the hydraulic chamber (19) or the oil pressure chamber (17) of the annular jack (16) through the control end (10).

6. A portable in-situ drilling shearing instrument for vegetation cover soil according to claim 5, characterized in that: The control terminal (10) comprises A cylindrical cavity, the cylindrical cavity being arranged inside the box of the control end (10), the cylindrical cavity being connected to the outlet end of the liquid pressurizer (4) via an oil guide pipe (24), and the cylindrical cavity being connected to the hydraulic chamber (19) or the oil pressure chamber (17) of the annular jack (16) via two other oil guide pipes (24); A displacement block (12), wherein the number of the displacement blocks (12) is two, and the two displacement blocks (12) are arranged on the arc surface of the cylindrical cavity, so that the interface connecting the hydraulic chamber (19) and the oil pressure chamber (17) is located on the same side of the line connecting the two displacement blocks (12), and the interface connecting the liquid pressurizer (4) is located on the other side of the line connecting the two displacement blocks (12); An oil guide component (13), the oil guide component (13) being fan-shaped, and the arc surface of the oil guide component (13) being slidably connected to the arc surface between the two blocking blocks (12) and away from the liquid pressurizer (4); A control rod (11) is mounted on the axis of the cylindrical cavity, the control rod (11) is fixedly connected to the center of the oil guide component (13), one end of the control rod (11) extends out of the box body of the control end (10), and the control rod (11) controls the oil guide component (13) to rotate along the arc surface.

7. A portable in-situ drilling shearing instrument for vegetation cover soil according to claim 1, characterized in that: The normal stress loading mechanism (2) comprises A flexible airbag (36), wherein the flexible airbag (36) is annular, the inner wall of the flexible airbag (36) is closely attached to the external threaded rod (38), is located above the shear probe (41), and is closely attached to the soil of the hole wall; A gas tank (28), wherein two cavities are arranged in an upper and lower manner, and a sealing screw (34) is provided between the two cavities to control the connection or separation of the two cavities, and the two cavities are used to contain two chemical substances that can react to generate gas; a glass plate (31) is provided on the upper cavity to observe the remaining amount of the chemical substances in the cavity; the gas tank (28) is connected to the flexible air bag (36) through a gas pipeline (35); A normal stress controller (27) is installed on a gas pipeline (35) between a gas tank (28) and a flexible air bag (36) and is used to display normal stress; a pressure gauge (29) and a gas valve (30) are provided on the gas pipeline (35) near the gas tank (28).

8. A portable in-situ drilling shearing instrument for vegetation cover soil according to claim 5, characterized in that: The liquid pressurizer (4) comprises A piston (7), wherein the bottom of the piston (7) is a cavity, the bottom of the piston (7) is slidably sealedly connected to the cavity via a rubber ring, and the top of the piston (7) is connected to one end of the pressure rod (5); An oil cylinder (6), wherein the oil cylinder (6) is connected to one end of a cavity at the bottom of the piston (7) via a one-way valve (8), and the other end of the cavity is connected to an oil guide pipe (24) via another one-way valve (8), and the oil guide pipe (24) is connected to a control end (10); An oil return valve (9), the oil return valve (9) is used to control whether the oil cylinder (6) and the oil guide pipe (24) are directly connected.

9. A method for using a portable in-situ drilling shearing instrument for vegetation cover soil as claimed in claim 1, characterized in that: Follow these steps: Step 1: The base (14) is installed and fixed just above the hole, and the shear probe (41) of the rotary shear mechanism (3) is sent to the shear position along the vertical hole, and the normal stress loading mechanism (2) is placed on the hole wall soil above the shear probe (41); Step 2: starting the normal stress loading mechanism (2) to apply a normal force to the hole wall soil above the shear probe (41); Step 3: shearing the soil; driving the force transmission rod (39) to generate a rotational torque by rotating the controller (15), driving the cam (42) inside the shearing probe (41) to rotate, and pushing the shearing piece of the shearing probe (41) to extend radially; returning the reading of the force sensor (37) to zero, starting the linear drive device, driving the internal threaded component (40) to move vertically upward, shearing the soil, observing the reading of the force sensor (37), and measuring the maximum tension; Step 4: Change the shear position and repeat steps 1 to 3 to measure the maximum tensile stress of the in-situ soil under different normal stresses, and obtain the shear strength of the soil based on the maximum tensile stress.

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