A soil shear strength in-situ testing device and method

Abstract

The present invention belongs to the technical field of geotechnical performance testing, and in particular, relates to an in-situ testing device and method for soil shear strength, comprising an outer cylinder and a shearing knife, air bags are respectively arranged on the outer walls of the upper and lower ends of the outer cylinder, and the outer cylinder is provided with a plurality of groups of mounting holes along the axial direction, each group of mounting holes includes a plurality of mounting holes evenly distributed on the circumference of the outer cylinder and arranged obliquely, and a shearing cylinder is arranged in the mounting hole; a first piston is slidably arranged on the inner wall of the shearing cylinder, a first piston rod is arranged at one end of the first piston, the first piston rod is obliquely extended to the outside of the outer cylinder and connected to the shearing knife; a driving mechanism is arranged inside the outer cylinder, and the driving mechanism is used to drive the first pistons in the plurality of shearing cylinders and the shearing knives to move synchronously. The present invention can further improve the bearing capacity of the shearing knife, improve the tensile strength of the drilling shear test, ensure the smooth and uniform insertion of the shearing knife into the soil layer, ensure the consolidation of the shearing knife and the soil layer, and improve the accuracy of the drilling shear test.

Description

Technical Field

[0001] The invention belongs to the technical field of rock and soil performance testing, and in particular relates to an in-situ testing device and method for soil shear strength. Background Art

[0002] In geotechnical engineering technology, the shear strength index of soil, cohesion and internal friction angle are important mechanical properties and important parameters for engineering design calculations. Usually, indoor shear tests and in-situ shear tests are used to measure the shear strength index of soil. Indoor shear tests require on-site sampling, sample preparation and other processes, which greatly disturb the soil. Various factors will cause a large discrepancy between the test results and the actual results. In-situ shear tests are carried out in situ on the soil, and the soil maintains its natural moisture content and natural stress state, making the test results true and reliable.

[0003] For example, the invention patent with publication number CN104458445B discloses an in-situ soil in-hole shear test device and test method, which includes a shear cylinder, a shear knife, an air bag, etc. The intersection angle between the shear knife outside the shear cylinder and the shear cylinder is 45°. The air bag expands, driving the shear cylinder to expand, so that the shear knife is inserted into the borehole wall. The consolidation test is maintained for a certain period of time, and finally the shear operation is carried out. The test device is lifted by a lifting device. During the soil shearing process, relevant detection instruments are observed and the shear force readings are recorded until the soil is sheared and damaged, and the test ends.

[0004] In the prior art, since the shear cutter and the hole wall are arranged at an angle, and the airbag expands almost horizontally to drive the shear cutter to insert into the hole wall, there is a large friction between the inclined shear cutter and the soil. The shear cutter will further squeeze the soil layer during the process of inserting into the soil, resulting in deformation of the hole wall or the shear cutter. Secondly, the shear cutter is driven by the airbag, so the depth of insertion of the shear cutter into the hole wall is limited. In addition, the airbag driving method will cause the shear cutters to be unable to be inserted into the soil uniformly, which ultimately affects the consolidation degree of the shear cutter and the soil, thereby reducing the accuracy of the drilling shear test. Summary of the invention

[0005] In view of the technical problems existing in the background technology, the present invention provides an in-situ testing device and method for the shear strength of soil.

[0006] To achieve the above purpose, the technical solution provided by the present invention is:

[0007] A soil shear strength in-situ testing device comprises an airbag, an outer cylinder, a shearing cylinder and a shearing knife, wherein the airbags are respectively arranged on the outer walls at the upper and lower ends of the outer cylinder, and the outer cylinder is provided with a plurality of groups of mounting holes along the axial direction, and each group of mounting holes comprises a plurality of mounting holes which are evenly distributed on the circumference of the outer cylinder and arranged obliquely, and the shearing cylinder is arranged in the mounting hole; a first piston is slidably arranged on the inner wall of the shearing cylinder, a first piston rod is arranged at one end of the first piston, the first piston rod is obliquely extended to the outside of the outer cylinder and is connected to the shearing knife; a driving mechanism is arranged inside the outer cylinder, and the driving mechanism is used to drive the first pistons in the plurality of shearing cylinders and the shearing knives to move synchronously.

[0008] Optionally, the driving mechanism includes a cylinder, a connecting disk and an inner tube, the cylinder includes a cylinder body, a second piston and a second piston rod, the bottom end of the cylinder body is arranged on the inner wall of the outer tube, and there is a gap between the upper part of the cylinder body and the outer tube, the inner tube is slidably arranged on the outer wall of the cylinder body, the upper end of the inner tube is detachably connected with a connecting disk, and a connecting rod is integrally extended from the bottom end of the connecting disk, a second piston is slidably arranged inside the cylinder body, a second piston rod is arranged at one end of the second piston, the second piston rod extends upward and is detachably connected to the connecting rod; a hinged portion is arranged at the bottom end of the first piston, a driving rod is hinged on the hinged portion, and one end of the driving rod is hinged to the inner tube.

[0009] Optionally, the upper end of the cylinder body is detachably connected to a guide cylinder, and a first pressure cover is provided at the upper end of the guide cylinder, and the first pressure cover and the outer cylinder are detachably connected; a plurality of sliding grooves are evenly distributed on the circumference of the guide cylinder, and a plurality of sliding blocks corresponding to the sliding grooves are evenly distributed on the circumference of the connecting disk, the connecting disk is slidably set on the inner wall of the guide cylinder, and the sliding block is slidably set in the sliding groove, and one end of the sliding block extends to the outside of the guide cylinder and is connected to the inner cylinder.

[0010] Optionally, a plurality of avoidance grooves are evenly distributed on the circumference of the inner wall of the first pressure cover, and the avoidance grooves are located directly above the sliding groove.

[0011] Optionally, a limiting ring is provided at the upper end of the second piston rod, and a spring is sleeved on the second piston rod, one end of the spring is connected to the limiting ring, and the other end is connected to the inner wall of the bottom end of the guide cylinder.

[0012] Optionally, a first flow channel is provided inside the second piston, a second flow channel is provided inside the connecting rod, and the first flow channel and the second flow channel are connected; a top cover is provided at the upper end of the first pressure cover, a first gas source distributor is provided inside the top cover, a second gas source distributor is provided at the end of the second piston rod, the second gas source distributor is provided inside the cylinder, one interface of the first gas source distributor is connected to the air bag at the upper part of the outer tube through a first pipe, another interface of the first gas source distributor is connected to the second flow channel through a second pipe, one interface of the second gas source distributor is connected to the cylinder through a third pipe, and another interface of the second gas source distributor is connected to the air bag at the lower part of the outer tube through a fourth pipe.

[0013] Optionally, a plurality of connecting blocks are evenly distributed on the circumference of the inner cylinder, a through groove is provided in the connecting block, a plurality of hinge holes connected to the through groove are provided on the connecting block, one end of the driving rod is provided in the through groove and hinged to the hinge hole; a sliding ring is provided at the bottom end of the inner cylinder, and the sliding ring is slidably arranged close to the inner wall of the outer cylinder.

[0014] Optionally, a plurality of mounting grooves are evenly distributed on the circumference of the upper end of the inner cylinder, the mounting grooves correspond to the connecting blocks one by one, and the sliding blocks are cooperatively arranged in the mounting grooves.

[0015] Optionally, an arc-shaped connecting cover is provided at one end of the shearing cylinder, an arc-shaped connecting groove is provided at the upper end of the mounting hole, the connecting groove and the mounting hole are coaxial, and the connecting cover is arranged in the connecting groove; a storage groove is provided at the outer end of the shearing cylinder, and the shearing knife can be accommodated in the storage groove; an arc-shaped guard edge is provided at the bottom end of the mounting hole, and the bottom end of the shearing cylinder is arranged close to the guard edge.

[0016] A drilling shear test method comprises the following steps:

[0017] (1) Drilling: Use a drilling rig to drill to the test depth and keep the hole wall smooth;

[0018] (2) Assemble the in-situ test device for soil shear strength: On the ground, first install the inner cylinder so that the inner cylinder is set on the inner wall of the outer cylinder and the inner cylinder can slide relative to the inner wall of the outer cylinder; connect the drive rod to the bottom end of the first piston in advance, and then install the shear cylinder and the shear knife on the outer wall of the outer cylinder. After the shear cylinder is installed, the drive rod is set in the cavity between the outer cylinder and the inner cylinder, and then one end of the drive rod is hinged to the inner cylinder. When the drive rod and the inner cylinder are hinged, a person's hand reaches into the inner cylinder and operates through the operating hole. Then connect the cylinder to the inner wall of the outer cylinder so that the outer wall of the cylinder body is close to the inner wall of the inner cylinder; then connect the guide cylinder and the connecting disk so that the slider of the connecting disk slides and fits on the slide groove of the guide cylinder, and rotate the guide cylinder and the connecting disk synchronously so that the connecting rod at the bottom of the connecting disk is threadedly connected to the second piston rod; finally, install the top cover;

[0019] (3) Lowering equipment: Use lifting equipment to lower the assembled soil shear strength in-situ test device to the test depth;

[0020] (4) Consolidation: Ventilate the airbag to expand the entire soil shear strength in-situ test device to the hole wall, then ventilate to drive the cylinder, which drives the shear knife to extend upward and insert into the borehole wall, and maintain the consolidation test for a fixed time;

[0021] (5) Shearing: After the consolidation process is completed, the assembled soil shear strength in-situ test device is lifted up using a lifting device. The shear cutter will shear the soil outside the borehole wall and record the shear force in real time until the soil is sheared and the test is completed.

[0022] The present invention has the following advantages and beneficial effects:

[0023] In the present invention, the shearing knife and the hole wall are arranged at an angle, which can further improve the bearing capacity of the shearing knife and improve the tensile strength of the drilling shear test compared to the method in which the shearing knife is perpendicular to the hole wall and inserted horizontally. Through the driving mechanism, a plurality of shearing knives are driven to be inclined upward and synchronously inserted into the hole wall, so as to avoid the shearing knife being inserted perpendicular to the hole wall and horizontally, resulting in large friction between the shearing knife and the soil, squeezing the soil layer, causing deformation of the hole wall, etc., thereby ensuring that the shearing knife is smoothly and evenly inserted into the soil layer, ensuring the consolidation of the shearing knife and the soil layer, and improving the accuracy of the drilling shear test. By driving by means of a cylinder or the like, a plurality of shearing knives are synchronously controlled to be inclined upward and inserted into the soil layer, and the insertion depth of the soil layer can be adjusted, so that it is suitable for shear strength parameter testing of various soft, medium and hard soils. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural diagram of the in-situ testing device for the shear strength of soil in the present invention;

[0025] Figure 2 for Figure 1 A partial enlarged view of point a in the middle;

[0026] Figure 3 A half-section view of an in-situ soil shear strength testing device according to the present invention;

[0027] Figure 4 for Figure 3 The cross-sectional view along the AA direction;

[0028] Figure 5 for Figure 3 A partial enlarged view of point b in the middle;

[0029] Figure 6 It is a structural diagram of the outer cylinder in the present invention;

[0030] Figure 7A half-section view of the outer cylinder of the present invention;

[0031] Figure 8 A half-section view of a cylinder body in the present invention;

[0032] Fig. 9 for Figure 8 The cross-sectional view along the BB direction;

[0033] Fig.10 It is a structural diagram of the second piston, the second piston rod, the second gas source distributor and other components in the present invention;

[0034] Fig.11 It is a structural diagram of the connection disk in the present invention;

[0035] Fig.12 This is one of the structural diagrams of the guide cylinder in the present invention;

[0036] Fig.13 This is the second structural diagram of the guide cylinder in the present invention;

[0037] Fig.14 It is a structural diagram of the shearing cylinder in the present invention;

[0038] Fig.15 A half-section view of the shearing cylinder of the present invention;

[0039] Fig.16 It is a structural diagram of the inner cylinder in the present invention;

[0040] Fig.17 It is a structural diagram of the first piston, the first piston rod and the shearing knife in the present invention;

[0041] Fig.18 This is one of the structural diagrams of the top cover in the present invention;

[0042] Fig.19 This is the second structural diagram of the top cover in the present invention.

[0043] Figure numerals: 1-outer cylinder, 11-first annular groove, 12-second annular groove, 13-first inner hole, 14-second inner hole, 141-third inner hole, 142-first connecting hole, 15-fourth inner hole, 151-first threaded hole, 16-mounting hole, 17-connecting groove, 18-second threaded hole, 19-rib, 2-cylinder body, 21-fifth inner hole, 211-third threaded hole, 22-sixth inner hole, 23-seventh inner hole, 231-inlet flow channel, 24-eighth inner hole, 25-second gland, 251-second connecting hole, 3-second piston rod, 31-second piston, 32-second gas source distributor, 321-first joint, 322-second joint, 323-third pipeline, 324-fourth pipeline, 33-limiting ring, 34-first flow channel, 35-spring, 4-connecting rod, 41-connecting plate, 42-second flow channel, 43-slider, 44-third connecting hole, 5-guide cylinder, 51-first pressure cover, 52-slide groove, 53-avoidance groove, 54-fourth connecting hole, 55-ninth inner hole, 56-fifth connecting hole, 6-inner cylinder, 61-installation groove, 62-fourth threaded hole, 63-connecting block, 64-through groove, 65-hinge hole, 66-sliding ring, 67-operating groove, 7-shearing cylinder, 71-connecting cover, 72-sixth connecting hole, 73-first slide hole, 74-storage groove, 75-second slide hole, 8-first piston, 81-first piston rod, 82-shearing knife, 83-hinge part, 84-driving rod, 9-top cover, 91-seventh connecting hole, 92-hook, 93-air inlet, 94-limiting protrusion, 95-first air source distributor, 96-first pipeline, 97-second pipeline, 10-air bag. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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.

[0045] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] Example 1

[0047] like Figure 1 to Figure 5 As shown, an in-situ testing device for soil shear strength includes an air bag 10, an outer cylinder 1, a shear cylinder 7, a shear knife 82 and other components.

[0048] like Figure 1 to Figure 7As shown, the outer walls at the upper and lower ends of the outer tube 1 are respectively provided with a first annular groove 11 and a second annular groove 12 , and the outer walls at the upper and lower ends of the outer tube 1 are respectively provided with airbags 10 , which are installed on the first annular groove 11 and the second annular groove 12 .

[0049] like Figure 1 to Figure 7 , Fig.14 , Fig.15 and Fig.17 As shown, the outer cylinder 1 is axially arranged with several groups of mounting holes 16, and each group of mounting holes 16 includes several mounting holes 16 evenly distributed on the circumference of the outer cylinder 1 and arranged obliquely, and the inclination angle of the mounting holes 16 is preferably 45°. A shearing cylinder 7 is arranged in the mounting hole 16, and a first piston 8 is slidably arranged on the inner wall of the shearing cylinder 7. A first piston rod 81 is arranged at one end of the first piston 8, and the first piston rod 81 is obliquely extended to the outside of the outer cylinder 1 and connected to the shearing knife 82. Specifically: a first sliding hole 73 and a second sliding hole 75 are arranged in the shearing cylinder 7, the first sliding hole 73 and the second sliding hole 75 are concentrically arranged, and the diameter of the first sliding hole 73 is smaller than the diameter of the second sliding hole 75, the first piston 8 is slidably arranged in the second sliding hole 75, and the first piston rod 81 is slidably arranged in the first sliding hole 73. A driving mechanism is provided inside the outer cylinder 1, which is used to drive the first pistons 8 and shear knives 82 in the plurality of shear cylinders 7 to move synchronously. When the first piston 8 slides along the inner wall of the shear cylinder 7, the shear knives 82 are driven to extend obliquely upward to the outside of the outer cylinder 1 and insert into the soil.

[0050] In the present invention, the shearing knife 82 and the hole wall are arranged obliquely, which can further improve the bearing capacity of the shearing knife 82 and the tensile strength of the in-situ testing device for soil shear strength compared to the method in which the shearing knife 82 is perpendicular to the hole wall and inserted horizontally. Through the driving mechanism, a plurality of shearing knives 82 are driven to be inclined upward and synchronously inserted into the hole wall, so as to avoid the shearing knife 82 being inserted horizontally perpendicular to the hole wall, which causes large friction between the shearing knife 82 and the soil, squeezes the soil layer, causes deformation of the hole wall and the shearing knife 82, etc., thereby ensuring that the shearing knife 82 is smoothly and evenly inserted into the soil layer, especially hard soil, ensuring the consolidation of the shearing knife 82 and the soil layer, and improving the accuracy of the drilling shear test. By driving by means of a cylinder or the like, a plurality of shearing knives 82 are synchronously controlled to be inserted into the soil layer obliquely upward, and the insertion depth of the soil layer can be adjusted, so that it is suitable for shear strength parameter testing of various soft, medium and hard soils.

[0051] like Figures 1 to 13 as well as Fig.16As shown, the driving mechanism includes a cylinder, a connecting plate 41 and an inner tube 6. The cylinder includes a cylinder body 2, a second piston 31 and a second piston rod 3. The bottom end of the cylinder body 2 is arranged on the inner wall of the outer tube 1. There is a gap between the upper part of the cylinder body 2 and the outer tube 1. The inner tube 6 is slidably arranged on the outer wall of the cylinder body 2. The upper end of the inner tube 6 is detachably connected with the connecting plate 41. The bottom end of the connecting plate 41 is integrally extended with a connecting rod 4. The second piston 31 is slidably arranged inside the cylinder body 2. One end of the second piston 31 is provided with a second piston rod 3. The second piston rod 3 extends upward and is detachably connected to the connecting rod 4. The bottom end of each first piston 8 is provided with a hinged portion 83, and a driving rod 84 is hinged on the hinged portion 83. One end of the driving rod 84 is hinged with the inner tube 6. When the cylinder drives the inner tube 6 to rise relative to the outer tube 1, the first piston 8 can be driven to slide through the driving rod 84, and the shearing knife 82 is driven to extend upward and insert into the soil. This structure only needs to set up one cylinder to control the synchronous movement of a plurality of shearing knives 82, thereby ensuring that the shearing knives 82 are inserted into the soil evenly and smoothly.

[0052] Specific:

[0053] like Figure 6 and Figure 7 As shown, the inner part of the outer cylinder 1 is provided with a fourth inner hole 15, a first inner hole 13, a second inner hole 14, and a third inner hole 141 from top to bottom, wherein the inner diameter of the fourth inner hole 15 is larger than the inner diameter of the first inner hole 13, the inner diameter of the first inner hole 13 is larger than the inner diameter of the second inner hole 14, and the inner diameter of the second inner hole 14 is smaller than the inner diameter of the third inner hole 141. A plurality of first threaded holes 151 are evenly distributed on the inner circumference of the fourth inner hole 15, the first inner hole 13 and the third inner hole 141 are connected through a plurality of first connecting holes 142, and the plurality of first connecting holes 142 are evenly distributed around the outer side of the second inner hole 14. A plurality of second threaded holes 18 are evenly distributed on the inner circumference of the bottom end of the connecting groove 17.

[0054] like Figure 8 and Fig. 9 As shown, the inside of the cylinder body 2 is provided with a fifth inner hole 21, a sixth inner hole 22, a seventh inner hole 23 and an eighth inner hole 24 from top to bottom, a second gland 25 is provided at the bottom end of the cylinder body 2, a plurality of second connecting holes 251 are evenly distributed on the circumference of the second gland 25, and a plurality of third threaded holes 211 are evenly distributed on the circumference of the upper end of the cylinder body 2. The sixth inner hole 22 and the eighth inner hole 24 are connected through an intake flow channel 231, and the intake flow channel 231 is provided on the outside of the seventh inner hole 23.

[0055] like Fig.10As shown, the middle section of the second piston rod 3 is provided with a second piston 31, one end of the second piston rod 3 is connected to a second gas source distributor 32, and the second gas source distributor 32 has a first joint 321 and a second joint 322; the other end of the second piston rod 3 is provided with a limit ring 33, and the limit ring 33 is connected to a spring 35, and the spring 35 is sleeved on the second piston rod 3. A first flow channel 34 is provided inside the second piston rod 3, and the first flow channel 34 is communicated with the second gas source distributor 32.

[0056] like Fig.11 As shown, a connecting rod 4 is integrally extended from the bottom end of the connecting disk 41 , a plurality of sliders 43 are evenly distributed on the circumference of the connecting disk 41 , each slider 43 is provided with a third connecting hole 44 , and a second flow channel 42 is provided inside the connecting disk 41 and the connecting rod 4 .

[0057] like Fig.12 and Fig.13 As shown, the upper end of the guide cylinder 5 is provided with a first gland 51, and a plurality of fourth connection holes 54 are evenly distributed on the circumference of the first gland 51, and a plurality of slide grooves 52 are evenly distributed on the circumference of the guide cylinder 5. A ninth inner hole 55 is provided in the bottom end of the guide cylinder 5, and a plurality of fifth connection holes 56 are provided on the circumference of the bottom end of the guide cylinder 5, and the fifth connection holes 56 are provided on the outside of the ninth inner hole 55. A plurality of avoidance grooves 53 are provided on the first gland 51, and the number and position of the avoidance grooves 53 correspond to the slide grooves 52, respectively, and the avoidance grooves 53 are provided directly above the slide grooves 52.

[0058] like Fig.16 As shown, a sliding ring 66 is provided on the outer wall of the bottom end of the inner cylinder 6, and a plurality of connecting blocks 63 are evenly distributed on the circumference of the inner cylinder 6. A through slot 64 is vertically provided on each connecting block 63, and a plurality of hinge holes 65 are provided on the side wall of the connecting block 63, which are arranged at a fixed distance and communicated with the through slot 64. A plurality of mounting grooves 61 are provided on the circumference of the upper end of the inner cylinder 6, and a fourth threaded hole 62 is provided on the bottom wall of the mounting groove 61. The number and position of the mounting grooves 61 correspond to the connecting blocks 63 one by one, respectively, and the mounting grooves 61 are arranged just above the connecting blocks 63. Among them, a plurality of operating grooves 67 are evenly distributed on the circumference of the inner cylinder 6, and the operating grooves 67 are arranged between two adjacent connecting blocks 63. When the driving rod 84 is installed later, a person's hand can be inserted into the inner cylinder 6, and extend to both sides of the connecting block 63 through the operating groove 67, so as to install the driving rod 84 on the hinge hole 65.

[0059] like Figures 1 to 13 as well as Fig.16 As shown, the outer wall of the cylinder body 2 is closely arranged on the inner wall of the second inner hole 14, and the second gland 25 is arranged in the third inner hole 141. When installing the cylinder body 2, the second connecting hole 251 on the second gland 25 is aligned with the first connecting hole 142, and the bolts are inserted to fix the cylinder body 2 on the inner wall of the outer tube 1.

[0060] like Figures 1 to 13 as well as Fig.16 As shown, the structure of the cylinder is as follows: the second piston 31 slides close to the inner wall of the sixth inner hole 22, the upper end of the second piston rod 3 passes through the fifth inner hole 21 to the upper part of the cylinder body 2, and the lower end of the second piston rod 3 passes through the seventh inner hole 23 to the eighth inner hole 24, so the second gas source distributor 32 is arranged in the eighth inner hole 24 to effectively protect the second gas source distributor 32.

[0061] like Figures 1 to 13 as well as Fig.16 As shown, the upper end of the cylinder body 2 is detachably connected with a guide tube 5, and the outer diameter of the guide tube 5 is the same as the outer diameter of the cylinder body 2. When the guide tube 5 is tightly arranged on the cylinder body 2, the fifth connecting hole 56 is aligned with the third threaded hole 211 respectively, and then the screw is screwed in to connect the guide tube 5 and the cylinder body 2 as a whole.

[0062] like Figures 1 to 13 as well as Fig.16 As shown, the upper end of the guide cylinder 5 is provided with a first gland 51, and the first gland 51 and the outer cylinder 1 are detachably connected. Specifically, the first gland 51 is arranged in cooperation in the fourth inner hole 15, and the fourth connection holes 54 of the first gland 51 are respectively aligned with the first threaded holes 151, and then the screws are screwed in to connect the first gland 51 and the outer cylinder 1 as a whole. Through the detachable connection, the cylinder body 2, the guide cylinder 5 and the outer cylinder 1 can be fixed as a whole.

[0063] like Figures 1 to 13 as well as Fig.16 As shown, a plurality of slide grooves 52 are evenly distributed on the circumference of the guide cylinder 5, a plurality of sliders 43 corresponding to the slide grooves 52 are evenly distributed on the circumference of the connection disk 41, the connection disk 41 is slidably arranged on the inner wall of the guide cylinder 5, the slider 43 is slidably arranged in the slide groove 52, and one end of the slider 43 extends outward from the guide cylinder 5 to connect with the inner cylinder 6. In this way, the sliding limit of the connection disk 41 can be achieved, and the connection between the connection disk 41 and the inner cylinder 6 can be achieved.

[0064] like Figure 3 and Figure 4 As shown, further, a limit ring 33 is provided at the upper end of the second piston rod 3, and a spring 35 is sleeved on the second piston rod 3, one end of the spring 35 is connected to the limit ring 33, and the other end is connected to the inner wall of the bottom end of the guide cylinder 5. When the second piston rod 3 is extended, the spring 35 is stretched, and at this time, the second piston rod 3 drives the connecting plate 41 and the inner cylinder 6 to rise synchronously, and drives the driving rod 84 through the inner cylinder 6, and then drives the first piston 8 to rise along the inner wall of the shearing cylinder 7, thereby controlling the shearing knife 82 to extend upward and insert into the soil. When the cylinder is exhausted, the spring 35 drives the second piston rod 3 to descend and reset, and the shearing knife 82 resets and shrinks, and leaves the soil.

[0065] like Figure 3 and Figure 4 As shown, an external thread is provided at the bottom end of the first connecting rod 4, the first connecting rod 4 is threadedly connected to the inner wall of the second piston rod 3, and the first flow channel 34 and the second flow channel 42 are directly connected.

[0066] like Figures 1 to 13 as well as Fig.16 As shown, the inner wall circumference of the first gland 51 is evenly distributed with a plurality of avoidance grooves 53, and the avoidance grooves 53 are located directly above the slide grooves 52. This is for the purpose of facilitating the installation of the connection disk 41. When installing the connection disk 41, the slider 43 of the connection disk 41 can be aligned with the avoidance grooves 53, and then lowered, so that the slider 43 can be inserted into the slide groove 52, and the sliding connection between the connection disk 41 and the guide cylinder 5 is completed; then the connecting rod 4 is aligned with the second piston rod 3, the guide cylinder 5 and the connection disk 41 are rotated as a whole, and the connecting rod 4 is screwed into the second piston rod 3, and the installation and fixation of the connecting rod 4 and the second piston rod 3 are completed. This installation structure is convenient for disassembly and assembly.

[0067] like Figures 1 to 13 as well as Figure 16 to Figure 19 As shown, the interior of the second piston 31 is provided with a first flow channel 34, the interior of the connecting rod 4 is provided with a second flow channel 42, and the first flow channel 34 and the second flow channel 42 are connected. The upper end of the first gland 51 is provided with a top cover 9, the interior of the top cover 9 is provided with an air inlet 93, the air inlet 93 is provided with a first gas source distributor 95, and the end of the second piston rod 3 is provided with a second gas source distributor 32. One interface of the first gas source distributor 95 is connected to the air bag 10 at the upper part of the outer tube 1 through a first pipeline 96, and the other interface of the first gas source distributor 95 is connected to the second flow channel 42 through a second pipeline 97. The first joint 321 of the second gas source distributor 32 is connected to the intake flow channel 231 of the cylinder body 2 through a third pipeline 323, and the second joint 322 of the second gas source distributor 32 is connected to the air bag 10 at the lower part of the outer tube 1 through a fourth pipeline 324. The first pipeline 96, the second pipeline 97, the third pipeline 323 and the fourth pipeline 324 are all hoses to adapt to the telescopic movement of the second piston rod 3. In this way, the gas source can be distributed to the airbag 10 at the upper end and to the second gas source distributor 32 at the lower end through the first gas source distributor 95, and then distributed again by the second gas source distributor 32 to distribute the gas source to the airbag 10 and the cylinder at the lower end. In this structure, the air pipe is integrated in the outer tube, and the internal pipeline is effectively protected. For example, some control lines of the control gas source distributor can be arranged in the outer tube 1.

[0068] like Figures 1 to 13 as well as Figure 16 to Figure 19As shown, the top cover 9 is evenly distributed with a number of seventh connection holes 91 on its circumference. The top cover 9 is arranged on the upper part of the first gland 51, and the seventh connection holes 91 are aligned with the fourth connection holes 54. Screws are inserted to connect the top cover 9, the first gland 51 and the outer cylinder 1 as a whole. A hook 92 is arranged on the upper part of the top cover 9, which is connected to the pull rope of the lifting device through the hook 92. At the same time, a number of limiting protrusions 94 are evenly distributed on the circumference of the bottom end of the top cover 9. The number and position of the limiting protrusions 94 correspond to the avoidance grooves 53 respectively. The limiting protrusions 94 are arranged in the avoidance grooves 53 in cooperation, so that the top cover 9 presses the first gland 51 to achieve complete sealing.

[0069] like Figures 1 to 13 as well as Figure 16 to Figure 19 As shown, a plurality of connecting blocks 63 are evenly distributed on the circumference of the inner cylinder 6, a through slot 64 is provided in the connecting block 63, a plurality of hinge holes 65 connected with the through slot 64 are provided on the connecting block 63, one end of the driving rod 84 is provided in the through slot 64 and hinged with the hinge hole 65; a sliding ring 66 is provided at the bottom end of the inner cylinder 6, and the sliding ring 66 is slidably arranged close to the inner wall of the outer cylinder. In this way, the lifting and lowering limit of the inner cylinder 6 can be ensured, and at the same time, the linkage of the inner cylinder 6 and the first piston 8 is realized through the connection between the driving rod 84 and the hinge hole 65.

[0070] like Figures 1 to 13 as well as Figure 16 to Figure 19 As shown, a plurality of mounting grooves 61 are evenly distributed on the circumference of the upper end of the inner cylinder 6, and the mounting grooves 61 correspond to the connecting blocks 63 one by one. The slider 43 is cooperatively arranged in the mounting groove 61, and the fourth threaded hole 62 is aligned with the third connecting hole 44. Then, the screw is screwed in to connect the slider 43 and the inner cylinder 6 as a whole, thereby realizing a detachable connection between the slider 43 and the inner cylinder 6.

[0071] like Figure 1 to Figure 7 , Fig.14 , Fig.15 As shown, an arc-shaped connection cover 71 is provided at one end of the shearing cylinder 7, and a plurality of sixth connection holes 72 are provided on the connection cover 71. An arc-shaped connection groove 17 is provided at the upper end of the mounting hole 16. The connection groove 17 and the mounting hole 16 are coaxial. The connection cover 71 is arranged in the connection groove 17, and the sixth connection hole 72 is aligned with the second threaded hole 18. Then the screw is screwed in to fix the shearing cylinder 7 and the outer cylinder 1. This structure can greatly reduce the occupied area of ​​the shearing cylinder 7. The installation and fixation of the shearing cylinder 7 are achieved through the arc-shaped connection cover 71. For the shearing cylinder 7 that is set obliquely, the protruding area of ​​the shearing cylinder 7 can be greatly reduced, ensuring that the outermost side of the shearing cylinder 7 is located within the outer diameter of the airbag 10, and ensuring that the shearing cylinder 7 will not rub against the wall of the drilled hole during the lowering or lifting process (such as Figure 3 as shown).

[0072] like Figure 3 , Figure 4 as well as Figure 5As shown, the outer end of the shearing cylinder 7 is provided with a receiving groove 74, which is provided on the inner wall of the first sliding hole 73, and the shearing knife 82 can be received in the receiving groove 74. In this way, the shearing knife 82 can be partially received in the receiving groove 74, and the shearing knife 82 is slidably limited against the inner wall of the receiving groove 74 to prevent the shearing knife 82 from rotating. In this way, the length of the shearing knife 82 can be guaranteed, and after the shearing knife 82 is received, it is ensured that the shearing knife 82 will not rub against the hole wall of the drilled hole during the lowering or lifting of the shearing cylinder 7 (such as Figure 3 as shown).

[0073] like Figure 3 , Figure 4 as well as Figure 5 As shown, the bottom end of the mounting hole 16 is provided with an arc-shaped retaining edge 19, and the bottom end of the shearing cylinder 7 is arranged close to the retaining edge 19 to achieve the limited installation of the shearing cylinder 7. The arc-shaped connecting grooves 17, one below and one above, correspond to each other, limit the diagonal position of the shearing cylinder 7, and achieve stable and reliable installation of the shearing cylinder 7. The connecting groove 17 is located directly above the mounting hole 16, and a connecting cover 71 is provided in the connecting groove 17. The shearing cylinder 7 is limited in the mounting hole 16. At the same time, the retaining edge 19 is located directly below the mounting hole 16, and the bottom side of the shearing cylinder 7 is supported on the retaining edge 19. This connection and limiting structure can ensure that the shearing cylinder 7 is stably connected under the premise of reducing space occupation.

[0074] Example 2

[0075] A drilling shear test method comprises the following steps:

[0076] (1) Drilling: Use a drilling rig to drill to the test depth and keep the hole wall smooth.

[0077] (2) Assemble the in-situ test device for soil shear strength: On the ground, first install the inner cylinder 6 so that the inner cylinder 6 is set on the inner wall of the outer cylinder 1 and the inner cylinder 6 can slide relative to the inner wall of the outer cylinder 1; connect the drive rod 84 to the bottom end of the first piston 8 in advance, and then install the shear cylinder 7 and the shear knife 82 on the outer wall of the outer cylinder 1. After the shear cylinder 7 is installed, the drive rod 84 is set in the cavity between the outer cylinder 1 and the inner cylinder 6, and then one end of the drive rod 84 is hinged to the inner cylinder 6. When the drive rod 84 and the inner cylinder 6 are hinged, a person's hand reaches into the inner cylinder 6 and operates through the operation slot 67. Then connect the cylinder to the inner wall of the outer cylinder 1, so that the outer wall of the cylinder body 2 is close to the inner wall of the inner cylinder 6, and the inner cylinder 6 achieves sliding limit; then connect the guide cylinder 5 and the connecting disk 41, so that the slider 43 of the connecting disk 41 slides and fits on the slide groove 52 of the guide cylinder 5, and rotate the guide cylinder 5 and the connecting disk 41 synchronously, so that the connecting rod 4 at the bottom of the connecting disk 41 and the second piston rod 3 are threadedly connected; finally, install the top cover 9.

[0078] (3) Lowering equipment: Use lifting equipment to lower the assembled soil shear strength in-situ test device to the test depth.

[0079] (4) Consolidation: Ventilation is performed to expand the airbag 10, so that the entire soil shear strength in-situ test device is fixed on the hole wall. Then ventilation is performed to drive the cylinder, which controls the inner tube 6 to rise, thereby driving the drive rod 84 to move, thereby linking the shear knife 82 to extend upward and insert into the borehole wall, and maintaining the consolidation test for a fixed time (such as 15, 20, or 30 minutes).

[0080] (5) Shearing: After the consolidation process is completed, the assembled soil shear strength in-situ test device is lifted up using a lifting device. The shear knife 82 will shear the soil outside the borehole wall and record the shear force in real time until the soil is sheared and destroyed. The test is completed.

[0081] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An in-situ soil shear strength testing device, characterized in that: It includes an air bag, an outer cylinder, a shearing cylinder and a shearing knife. Air bags are respectively arranged on the outer walls of the upper and lower ends of the outer cylinder; the outer cylinder is provided with a plurality of groups of mounting holes along the axial direction; each group of mounting holes includes a plurality of mounting holes evenly distributed on the circumference of the outer cylinder and arranged obliquely; a shearing cylinder is arranged in the mounting hole; a first piston is slidably arranged on the inner wall of the shearing cylinder; a first piston rod is arranged at one end of the first piston; the first piston rod is obliquely extended to the outside of the outer cylinder and connected to the shearing knife; A driving mechanism is arranged inside the outer cylinder, and the driving mechanism is used to drive the first pistons and shearing knives in the plurality of shearing cylinders to move synchronously; The driving mechanism comprises a cylinder, a connecting plate and an inner cylinder, the cylinder comprises a cylinder body, a second piston and a second piston rod, the bottom end of the cylinder body is arranged on the inner wall of the outer cylinder, a gap is provided between the upper part of the cylinder body and the outer cylinder, the inner cylinder is slidably arranged on the outer wall of the cylinder body, the upper end of the inner cylinder is detachably connected with a connecting plate, a connecting rod is integrally extended from the bottom end of the connecting plate, a second piston is slidably arranged inside the cylinder body, a second piston rod is arranged at one end of the second piston, the second piston rod extends upward and is detachably connected to the connecting rod; The bottom end of the first piston is provided with a hinged portion, a driving rod is hingedly connected to the hinged portion, and one end of the driving rod is hingedly connected to the inner cylinder; The upper end of the cylinder body is detachably connected to a guide cylinder, and a first pressure cover is provided at the upper end of the guide cylinder, and the first pressure cover is detachably connected to the outer cylinder; a plurality of slide grooves are evenly distributed on the circumference of the guide cylinder, and a plurality of sliders corresponding to the slide grooves are evenly distributed on the circumference of the connecting disk, the connecting disk is slidably arranged on the inner wall of the guide cylinder, and the slider is slidably arranged in the slide groove, and one end of the slider extends to the outside of the guide cylinder and is connected to the inner cylinder.

2. The in-situ soil shear strength testing device according to claim 1, characterized in that: A plurality of avoidance grooves are evenly distributed on the circumference of the inner wall of the first gland, and the avoidance grooves are located directly above the slide grooves.

3. The in-situ soil shear strength testing device according to claim 1, characterized in that: A limiting ring is arranged at the upper end of the second piston rod, and a spring is sleeved on the second piston rod. One end of the spring is connected to the limiting ring, and the other end is connected to the inner wall of the bottom end of the guide cylinder.

4. The in-situ soil shear strength testing device according to claim 1, characterized in that: A first flow channel is provided inside the second piston, a second flow channel is provided inside the connecting rod, and the first flow channel and the second flow channel are connected; a top cover is provided at the upper end of the first pressure cover, a first gas source distributor is provided inside the top cover, a second gas source distributor is provided at the end of the second piston rod, the second gas source distributor is provided inside the cylinder, one interface of the first gas source distributor is connected to the air bag at the upper part of the outer tube through a first pipe, another interface of the first gas source distributor is connected to the second flow channel through a second pipe, one interface of the second gas source distributor is connected to the cylinder body through a third pipe, and another interface of the second gas source distributor is connected to the air bag at the lower part of the outer tube through a fourth pipe.

5. The in-situ soil shear strength testing device according to claim 1, characterized in that: A plurality of connection blocks are evenly distributed on the circumference of the inner cylinder, a through groove is arranged in the connection block, a plurality of hinge holes connected with the through groove are arranged on the connection block, one end of the driving rod is arranged in the through groove and hinged with the hinge hole; a sliding ring is arranged at the bottom end of the inner cylinder, and the sliding ring is slidably arranged close to the inner wall of the outer cylinder.

6. The in-situ soil shear strength testing device according to claim 5, characterized in that: A plurality of mounting grooves are evenly distributed on the circumference of the upper end of the inner cylinder, the mounting grooves correspond to the connecting blocks one by one, and the sliding blocks are cooperatively arranged in the mounting grooves.

7. The in-situ soil shear strength testing device according to claim 1, characterized in that: One end of the shearing cylinder is provided with an arc-shaped connecting cover, the upper end of the mounting hole is provided with an arc-shaped connecting groove, the connecting groove and the mounting hole are coaxial, and the connecting cover is arranged in the connecting groove; the outer end of the shearing cylinder is provided with a storage groove, and the shearing knife can be stored in the storage groove; the bottom end of the mounting hole is provided with an arc-shaped guard edge, and the bottom end of the shearing cylinder is arranged close to the guard edge.

8. A method for performing a borehole shear test using the soil shear strength in-situ testing device according to any one of claims 1 to 7, comprising the following steps: (1) Drilling: Use a drilling rig to drill to the test depth and keep the hole wall smooth; (2) Assemble the in-situ test device for soil shear strength: first install the inner cylinder so that the inner cylinder is set on the inner wall of the outer cylinder, then install the shear cylinder and the shear knife on the outer wall of the outer cylinder. After the shear cylinder is installed, the drive rod is set in the cavity between the outer cylinder and the inner cylinder, and then one end of the drive rod is hinged to the inner cylinder; then connect the cylinder to the inner wall of the outer cylinder so that the outer wall of the cylinder body is close to the inner wall of the inner cylinder; then connect the guide cylinder and the connecting disk so that the slider of the connecting disk slides and fits on the slide groove of the guide cylinder, and rotate the guide cylinder and the connecting disk synchronously so that the connecting rod at the bottom of the connecting disk is threadedly connected with the second piston rod; finally, install the top cover; (3) Lowering equipment: Use lifting equipment to lower the assembled soil shear strength in-situ test device to the test depth; (4) Consolidation: Ventilate the airbag to expand the entire soil shear strength in-situ test device to the hole wall, then ventilate to drive the cylinder, which drives the shear knife to extend upward and insert into the borehole wall, and maintain the consolidation test for a fixed time; (5) Shearing: After the consolidation process is completed, the assembled soil shear strength in-situ test device is lifted up using a lifting device. The shear cutter will shear the soil outside the borehole wall and record the shear force in real time until the soil is sheared and the test is completed.

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