A large direct shear apparatus for model test of horizontal shear bearing capacity of composite foundation

Abstract

The invention belongs to the technical field of shear force testing, and specifically is a large-scale direct shear instrument for testing a model test of the horizontal shear bearing capacity of a composite foundation, comprising a support part, a control mechanism and a detection mechanism; the support part comprises a bearing bracket, an upper detection mold frame, a lower detection mold frame, an upper fixed crossbeam and a side closed template, the lower detection mold frame is fixedly installed on the upper end surface of the bearing bracket, and the upper detection mold frame is arranged directly above the lower detection mold frame; the upper fixed crossbeam passes through the upper detection mold frame and is fixedly connected to the side walls of the bearing bracket at both ends, and the side closed template is detachably installed between the upper detection mold frame and the lower detection mold frame; the detection mechanism comprises a top pressure plate and a pressure sensor fixedly installed on the side wall of the top pressure plate; the control mechanism comprises a control cylinder, an installation box and a control shaft, the installation box is fixedly installed on the bearing bracket, and the control shaft is slidably installed in the inner cavity of the installation box; the above-mentioned structures are coordinated to improve the accuracy of the test results and meet the actual use requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of shear force testing, in particular to a large direct shear apparatus for testing a model test of the horizontal shear bearing capacity of a composite foundation. Background Art

[0002] With the development of geotechnical centrifuge model test technology, centrifuge model test plays an indispensable and important role in solving geotechnical engineering problems, such as the stability of embankments and slopes on composite foundations. Cement-soil pile reinforced slopes usually appear in the form of pile groups, which mainly bear the horizontal landslide thrust. In order to verify the conclusions of numerical simulation, according to the force mechanism of cement-soil pile reinforced soil slopes, a horizontal shear model test equipment for cement-soil pile composite foundations was developed. It is used for laboratory simulation testing of mechanical parameters of composite foundation reinforced slope stability. The model test method is to reduce the prototype structure by a certain proportion and turn it into a model structure to carry out the test, and use the research results for the prototype test method.

[0003] The shear resistance of cement soil piles refers to the resistance of cement soil piles when forces are applied between two mutually perpendicular surfaces.

[0004] For example, Chinese patent with publication number CN114858620A discloses a concrete shear force testing device;

[0005] The Chinese patent with publication number CN208568497U discloses a concrete shear force detection device;

[0006] Chinese patent publication number CN116840075A discloses an in-situ multi-layer direct shear device and a direct shear test method.

[0007] Among them, in the technologies with publication numbers (CN114858620A, CN208568497U), the upper end surface of the pile body under test is not fixed, and when pressure is applied and the upper end of the pile body is deformed, the direction of the force on the outer wall of the pile body under test changes, thereby affecting the accuracy of the test;

[0008] Although the upper end of the pile body of the test section in publication number CN116840075A is fixed by pressure, this fixing method leads to an increase in friction between two adjacent plug-in boards, thereby affecting the experimental data of the test.

[0009] To this end, the present invention provides a large direct shear apparatus for a model test of the horizontal shear bearing capacity of a composite foundation. Summary of the invention

[0010] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0011] The technical solution adopted by the present invention to solve the technical problem is as follows: the large direct shear apparatus for testing the horizontal shear bearing capacity model of composite foundation described in the present invention comprises a support part, a control mechanism and a detection mechanism;

[0012] The support part includes a bearing bracket, an upper detection mold frame, a lower detection mold frame, an upper fixed beam and a side closed mold frame, the lower detection mold frame is fixedly installed on the upper end surface of the bearing bracket, and the upper detection mold frame is arranged directly above the lower detection mold frame;

[0013] The upper fixed crossbeam passes through the upper detection mold frame and both ends are fixedly connected to the side walls of the bearing bracket. The side closed template is detachably installed between the upper detection mold frame and the lower detection mold frame;

[0014] The detection mechanism includes a top pressure plate and a pressure sensor fixedly installed on the side wall of the top pressure plate;

[0015] The control mechanism includes a control cylinder, an installation box and a control shaft. The installation box is fixedly installed on the load-bearing bracket, the control shaft is slidably installed in the inner cavity of the installation box, and one end of the control shaft is fixedly connected to the top pressure plate. The control cylinder is fixedly installed on the outer wall of the load-bearing bracket, and the sliding of the control shaft is controlled by the control cylinder.

[0016] Preferably, a support rod is slidably installed inside the installation box, one end of the support rod passes through the top pressure plate and is elastically installed with a connecting sleeve, and a plug-in block for the connecting sleeve to be plugged into is fixedly installed on the outer wall of the side closed template, and the plug-in block and the connecting sleeve are fixed by a pin shaft.

[0017] Preferably, the movable end of the control cylinder is fixedly connected to the end of the control shaft away from the top pressure plate, the inner wall of the mounting box is rotatably mounted with a control gear, and the outer walls of the control shaft and the support rod are fixedly mounted with a control rack meshing with the control gear.

[0018] Preferably, an accommodating chamber is provided inside the installation box, an oil guide shaft is rotatably installed inside the accommodating chamber, a spiral oil guide groove is opened on the radial outer wall of the oil guide shaft, the oil guide shaft is located directly below the control gear, and the inner wall of the control gear begins to have a guide groove for the flow of lubricating oil.

[0019] Preferably, the inner wall of the oil guide shaft is rotatably mounted with a accommodating cylinder via a torsion spring, the axial end of the control gear is rotatably connected to the accommodating cylinder via a connecting shaft, the inner cavity of the accommodating cylinder is provided with a connecting shaft fixedly connected to the axial end of the control gear, a control ratchet rod is elastically mounted on the radial outer wall of the connecting shaft, and a control ratchet tooth cooperating with the control ratchet rod is fixedly mounted on the inner wall of the accommodating cylinder.

[0020] Preferably, a bearing plate is fixedly mounted on the outer wall of the mounting box, a plug-in shaft is fixedly mounted on the upper end surface of the bearing plate, one end of the plug-in shaft extends to the inner cavity of the oil guide shaft, a push rod is elastically mounted on the inner wall of the plug-in shaft, and a resistance bevel block is fixedly mounted on the inner wall of the oil guide shaft.

[0021] Preferably, the support rod is made of elastic material, an elastic rod is fixedly mounted on one axial end of the support rod, and the other end of the elastic rod is fixedly connected to the connecting sleeve;

[0022] One end of the support rod away from the elastic rod is fixedly connected with a mounting tube, and a knocking shaft for knocking the support rod is elastically mounted on the inner wall of the mounting tube.

[0023] Preferably, one end of the mounting tube away from the supporting rod is fixedly connected to a guide rod, a connecting plate is slidably mounted on the outer wall of the guide rod, and the outer wall of the tapping shaft is fixedly connected to the outer wall of the connecting plate.

[0024] Preferably, a control rod is slidably installed on the inner wall of the mounting cylinder, the control rod passes through the connecting plate, a receiving groove is provided on the radial outer wall of the control rod, an elastic plate is elastically installed in the receiving groove, a locking block for pressing the connecting plate is fixedly installed on the outer wall of the elastic plate, and a sliding inclined groove is provided on the connecting plate for the locking block to slide.

[0025] Preferably, a telescopic cylinder is fixedly mounted on the outer wall of the installation box, and the movable end of the telescopic cylinder is fixedly connected to the outer wall of the control rod;

[0026] A pressure rod for pressing the elastic plate is rotatably mounted on the inner wall of the installation box through a torsion spring, and one end of the pressure rod extends to the inner cavity of the accommodating groove.

[0027] The beneficial effects of the present invention are as follows:

[0028] 1. The present invention is provided with a bearing bracket, an upper detection formwork, a lower detection formwork, an upper fixed beam and a side closed formwork, the upper fixed beam runs through the upper detection formwork and both ends are fixedly connected to the side walls of the bearing bracket. After the cement soil pile is formed, the upper end of the cement soil pile to be tested is fixed to the bearing bracket by the upper fixed beam. By setting the upper fixed beam, compared with only fixing one end of the test wall, a shear wall with both ends fixed can be simulated during the test, and when two external forces are applied, the direction of the external force caused by the bending of the concrete can be prevented from being offset, thereby improving the accuracy of the test results and meeting the actual use requirements. In addition, compared with the measurement by pressing the plug-in board, the influence of the friction between two adjacent plug-in boards on the test data can be avoided, thereby further improving the accuracy of the test data;

[0029] 2. The present invention sets a connecting plate, and a tapping shaft is set on the outer wall of the connecting plate. The sliding control rod drives the elastic plate and the locking block to move synchronously until the locking block fits with the side wall of the connecting plate. The sliding control rod continues to drive the connecting plate away from the mounting tube through the locking block. At this time, the spring stores elastic potential energy, and then presses the elastic plate until the locking block is separated from the connecting plate. At this time, the spring releases elastic potential energy, driving the tapping shaft to tap the support rod, thereby realizing the tapping operation of the support rod, so as to facilitate the removal of the side closed template and improve the testing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] Figure 1 It is a schematic diagram of the overall structure of the device for making cement soil piles according to the present invention;

[0032] Figure 2 It is a schematic diagram of the overall structure of the device for testing shear force of the present invention;

[0033] Figure 3 It is a schematic diagram of the structure of the load-bearing bracket in the present invention;

[0034] Figure 4 It is a structural schematic diagram of the installation box in the present invention;

[0035] Figure 5 It is a structural schematic diagram of the control gear in the present invention;

[0036] Figure 6 It is a schematic diagram of the installation of the oil guide shaft in the present invention;

[0037] Figure 7 is a cross-sectional view of the oil guide shaft in the present invention;

[0038] Figure 8 It is a schematic diagram of the installation of the control ratchet in the present invention;

[0039] Fig. 9 It is a schematic diagram of the installation of the installation cylinder in the present invention;

[0040] Fig.10 yes Fig. 9 A partial enlarged view of the middle part;

[0041] Fig.11 It is a schematic diagram of the installation of the control rod in the present invention;

[0042] Fig.12 It is a schematic diagram of the installation of the tapping shaft in the present invention;

[0043] Fig.13 It is a schematic diagram of the installation of the elastic plate in the present invention.

[0044] In the figure: 1. load-bearing bracket; 2. control cylinder; 3. connecting sleeve; 4. lower detection mold frame; 5. side closed template; 6. top pressure plate; 7. installation box; 8. support rod; 9. upper fixed beam; 10. plug-in block; 11. upper detection mold frame; 12. control shaft; 13. control gear; 14. elastic rod; 15. oil guide shaft; 16. load-bearing plate; 17. connecting shaft; 18. guide groove; 19. accommodating cylinder; 20. control ratchet rod; 21. resistance inclined block; 22. top pressure rod; 23. plug-in shaft; 24. control ratchet; 25. telescopic cylinder; 26. control rod; 27. installation cylinder; 28. pressure rod; 29. ​​connecting plate; 30. tapping shaft; 31. guide rod; 32. locking block; 33. elastic plate. DETAILED DESCRIPTION

[0045] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0046] Embodiment 1: Figures 1 to 5 As shown, a large direct shear apparatus for a model test of the horizontal shear bearing capacity of a composite foundation according to an embodiment of the present invention comprises a support portion, a control mechanism and a detection mechanism.

[0047] The support part includes a bearing bracket 1, an upper detection formwork 11, a lower detection formwork 4, an upper fixed beam 9 and a side closed formwork 5, wherein the bearing bracket 1 is composed of an L-shaped steel plate and is used to provide support for the entire device.

[0048] The lower detection formwork 4 is fixedly installed on the upper end surface of the bearing bracket 1, and the upper detection formwork 11 is arranged directly above the lower detection formwork 4. The upper detection formwork 11 and the lower detection formwork 4 are a frame structure composed of L-shaped steel plates, and transparent glass is fixed on the side thereof by bolts to form a containing chamber for accommodating reinforced concrete. In addition, the setting of the transparent glass plate can penetrate the internal concrete during testing.

[0049] The upper fixed crossbeam 9 passes through the upper detection formwork 11 and both ends are fixedly connected to the side walls of the bearing bracket 1. After the cement soil pile is formed, the upper end of the cement soil pile to be tested is fixed to the bearing bracket 1 through the upper fixed crossbeam 9.

[0050] In the actual use of the cement soil pile, its bottom is connected to the foundation or floor slab, and its top is connected to the floor top slab. Through the setting of the upper fixed crossbeam 9, compared with the Chinese patent with publication number CN114858620A, in which only one end of the test wall is fixed, a cement soil pile with both ends fixed can be simulated during the detection. At the same time, the shear force is a pair of external forces with the same size and opposite directions at a close distance. Both ends of the cement soil pile are fixed. When two external forces are applied, compared with the Chinese patent with publication number CN208568497U, in which the upper box body is not fixed, the cement soil pile can be prevented from bending to cause the direction of the external force to shift, thereby improving the accuracy of the test result and adapting to actual use needs.

[0051] The side closed formwork 5 can be detachably installed between the upper detection formwork 11 and the lower detection formwork 4. When making cement soil piles, the two side closed formworks 5 are assembled into a cylindrical structure. The upper detection formwork 11 and the lower detection formwork 4 are connected through the cylindrical structure composed of the two side closed formworks 5, and the material is filled in to form a cement soil pile after solidification.

[0052] In this embodiment, before injecting the material, a concrete release agent needs to be evenly applied on the inner wall of the side closed formwork 5 .

[0053] During the test, the side closed formwork 5 needs to be removed first. The exposed unobstructed cement soil pile section is the test section. Two parallel, equal and staggered forces are applied on both sides of the test section to start the shear force test.

[0054] The detection mechanism includes a top pressure plate 6 and a pressure sensor fixedly installed on the side wall of the top pressure plate 6. The pressure sensor is used to detect the pressure value of the top pressure plate 6 on the concrete. Compared with the prior art method of converting shear force by measuring the oil pressure of the power source, the pressure value can be directly obtained, thereby reducing experimental errors.

[0055] The control mechanism includes a control cylinder 2, a mounting box 7 and a control shaft 12. The control cylinder 2 is a common hydraulic cylinder. The mounting box 7 is fixedly mounted on the supporting bracket 1. The control shaft 12 is slidably mounted in the inner cavity of the mounting box 7, and one end of the control shaft 12 is fixedly connected to the top pressure plate 6. The sliding control shaft 12 controls the sliding of the top pressure plate 6 until the top pressure plate 6 contacts the outside of the concrete column.

[0056] In this embodiment, two installation boxes 7 are symmetrically arranged on both sides of the cement soil pile, so that the two top pressure plates 6 can press the cement soil pile synchronously from both sides of the cement soil pile.

[0057] The control cylinder 2 is fixedly mounted on the outer wall of the bearing bracket 1 , and the sliding of the control shaft 12 is controlled by the control cylinder 2 , which provides pressure for the top pressure plate 6 to press the cement soil pile.

[0058] By directly pressing the cement soil pile with the top pressure plate 6 to detect the shear force, compared with the measurement by pressing the plug-in board in the Chinese patent with publication number CN116840075A, the influence of the friction between two adjacent plug-in boards on the detection data can be avoided, thereby further improving the accuracy of the detection data.

[0059] A support rod 8 is slidably installed inside the installation box 7, and the installation box 7 provides installation and sliding space for the support rod 8. One end of the support rod 8 passes through the top pressure plate 6 and is elastically installed with a connecting sleeve 3. The sliding support rod 8 controls the sliding of the connecting sleeve 3.

[0060] The outer wall of the side closed formwork 5 is fixedly installed with a plug-in block 10 for the connecting sleeve 3 to be plugged in. The plug-in block 10 and the connecting sleeve 3 are fixed by plugging and fixing through a pin shaft. The support rod 8 is slid until the connecting sleeve 3 and the plug-in block 10 are plugged in, thereby supporting the side closed formwork 5 to facilitate the injection of concrete. After the connecting sleeve 3 and the plug-in block 10 are plugged in, the connecting sleeve 3 and the plug-in block 10 are penetrated by the pin shaft to achieve the fixation of the connecting sleeve 3 and the plug-in block 10.

[0061] When removing the formwork, the reverse sliding support rod 8 drives the side closed formwork 5 to move away from the concrete column, thereby realizing the removal of the side closed formwork 5 .

[0062] The movable end of the control cylinder 2 is fixedly connected to an end of the control shaft 12 away from the top pressure plate 6, so that the control shaft 12 can be controlled to slide by the control cylinder 2.

[0063] A control gear 13 is rotatably mounted on the inner wall of the mounting box 7, and a control rack meshing with the control gear 13 is fixedly mounted on the outer walls of the control shaft 12 and the support rod 8. The sliding of the support rod 8 is controlled by the cooperation of the control rack and the control gear 13 through the sliding control shaft 12.

[0064] When testing the shear force, the movable end of the control cylinder 2 extends, driving the control shaft 12 to extend until the top pressure plate 6 presses the concrete. At the same time, the gear 13 is controlled to rotate and the support rod 8 is controlled to retract. During the retraction process of the support rod 8, the side closed formwork 5 can be easily removed.

[0065] During the cement soil pile manufacturing process, the movable end of the control cylinder 2 is reset and retracted, and the support rod 8 is controlled to extend through the control gear 13 to support the fixed side closed template 5.

[0066] In the process of making cement soil piles, a certain amount of cement solidification time is required. During this process, the side closed formwork 5 needs to maintain a supported state. The side closed formwork 5 is reset and retracted by the control cylinder 2. During this process, the internal oil cylinder of the control cylinder 2 maintains a low-pressure state, and the control circuit of the control cylinder 2 can remain in a power-off state, thereby protecting the control cylinder 2 and reducing the loss of electric energy.

[0067] Embodiment 2: Figures 6 to 13 As shown in Comparative Example 1, another embodiment of the present invention is:

[0068] The installation box 7 is provided with a containing cavity inside, and the containing cavity is used to store lubricating oil. During use, the lubricating oil provides lubrication protection for the control gear 13 and the control rack.

[0069] An oil guide shaft 15 is rotatably installed inside the accommodating cavity. A spiral oil guide groove is opened on the radial outer wall of the oil guide shaft 15. The oil guide groove is controlled to rotate by rotating the oil guide shaft 15, and the oil guide groove is immersed in the lubricating oil. The thick lubricating oil is controlled to rise along the oil guide groove through friction and inertia.

[0070] The oil guide shaft 15 is located directly below the control gear 13. The inner wall of the control gear 13 begins to have a guide groove 18 for the flow of lubricating oil. As the oil guide shaft 15 rotates, the lubricating oil enters the interior of the control gear 13. At this time, the rotating control gear 13 uses centrifugal force to throw the lubricating oil out, thereby realizing automatic lubrication of the control gear 13 and the control rack.

[0071] When the oil guide shaft 15 and the control gear 13 stop rotating, the lubricating oil flows back into the accommodating chamber due to the influence of gravity, thereby realizing automatic recovery of the lubricating oil.

[0072] The inner wall of the oil guide shaft 15 is rotatably mounted with a accommodating cylinder 19 via a torsion spring, a connecting shaft is provided at the bottom of the accommodating cylinder 19, a torsion spring is fixedly mounted on the outer wall of the connecting shaft, and the other end of the torsion spring is fixedly connected to the inner wall of the oil guide shaft 15. The rotating accommodating cylinder 19 controls the rotation of the oil guide shaft 15 through the elastic force of the torsion spring.

[0073] The axial end of the control gear 13 is rotatably connected to the accommodating cylinder 19 via a connecting shaft. The inner cavity of the accommodating cylinder 19 is provided with a connecting shaft 17 fixedly connected to the axial end of the control gear 13. Rotating the control gear 13 drives the connecting shaft 17 to rotate.

[0074] A control ratchet 20 is elastically mounted on the radial outer wall of the connecting shaft 17, and a control ratchet 24 cooperating with the control ratchet 20 is fixedly mounted on the inner wall of the accommodating tube 19. Through the cooperation between the control ratchet 20 and the control ratchet 24, one-way transmission of the connecting shaft 17 and the accommodating tube 19 is achieved.

[0075] During the process of extending the movable end of the control cylinder 2, the control gear 13 is driven to rotate. At this time, the accommodating tube 19 is driven to rotate through the cooperation of the control ratchet rod 20 and the control ratchet 24. Finally, the oil guide shaft 15 is driven to rotate through the elastic force of the torsion spring to facilitate the delivery of the lubricating oil. By delivering the lubricating oil, the sliding efficiency of the support rod 8 and the control shaft 12 can be improved, thereby facilitating the detection operation.

[0076] A bearing plate 16 is fixedly mounted on the outer wall of the installation box 7 , and a plug-in shaft 23 is fixedly mounted on the upper end surface of the bearing plate 16 . The plug-in shaft 23 is connected to the installation box 7 via the bearing plate 16 .

[0077] One end of the plug-in shaft 23 extends to the inner cavity of the oil guide shaft 15, and the plug-in shaft 23 is rotatably connected to the oil guide shaft 15. A push rod 22 is elastically installed on the inner wall of the plug-in shaft 23. The push rod 22 is affected by the elastic force and has a tendency to slide toward the outside of the plug-in shaft 23 in real time.

[0078] A resistance bevel block 21 is fixedly installed on the inner wall of the oil guide shaft 15, wherein the resistance bevel block 21 is inclined toward one side of the plug-in shaft 23. When the accommodating cylinder 19 controls the rotation of the oil guide shaft 15 through the torsion spring, the push rod 22 slides along the outer wall of the resistance bevel block 21. As the sliding occurs, the friction force between the push rod 22 and the resistance bevel block 21 gradually increases. At this time, the torsion spring stores elastic potential energy. When the push rod 22 separates from the resistance bevel block 21, the rotation resistance of the oil guide shaft 15 is instantly reduced. At this time, the torsion spring releases the elastic potential energy, thereby controlling the oil guide shaft 15 to rotate faster.

[0079] When the push rod 22 contacts the resistance bevel 21 again, the resistance to the rotation of the oil guide shaft 15 increases again, reducing the rotation speed of the oil guide shaft 15 at this time. Through the above-mentioned structural cooperation, the oil guide shaft 15 is controlled to switch between accelerated rotation and decelerated rotation, thereby facilitating the lubricating oil to rise along the oil guide groove and improving the transmission efficiency of the oil guide groove.

[0080] In this embodiment, the accommodating chamber is arranged below the control gear 13, which can facilitate the recovery of the lubricating oil compared with the method of directly arranging the accommodating chamber above and controlling the contact between the lubricating oil and the control gear 13 by gravity.

[0081] The support rod 8 is made of elastic material, and an elastic rod 14 is fixedly installed at one axial end of the support rod 8 . The other end of the elastic rod 14 is fixedly connected to the connecting sleeve 3 , and the elastic connection between the support rod 8 and the connecting sleeve 3 is achieved through the elastic rod 14 .

[0082] During the process of removing the side closed formwork 5, the support rod 8 is vibrated by knocking, thereby driving the side closed formwork 5 to vibrate, so as to facilitate the separation of the side closed formwork 5 from the concrete column, improve the disassembly efficiency, and further improve the test operation efficiency.

[0083] One end of the support rod 8 away from the elastic rod 14 is fixedly connected to the mounting tube 27, and the inner wall of the mounting tube 27 is elastically mounted with a tapping shaft 30 for tapping the support rod 8. The tapping shaft 30 is slid, and then the tapping shaft 30 is controlled by the elastic force exerted on the tapping shaft 30 to tap the support rod 8, so as to facilitate the operation of disassembling the side closed template 5.

[0084] One end of the mounting tube 27 away from the support rod 8 is fixedly connected to a guide rod 31, and a connecting plate 29 is slidably installed on the outer wall of the guide rod 31. The connecting plate 29 and the mounting tube 27 are slidably connected through the guide rod 31, wherein the outer wall of the connecting plate 29 is fixedly connected to a spring, and the other end of the spring is fixedly connected to the outer wall of the mounting tube 27.

[0085] The outer wall of the tapping shaft 30 is fixedly connected to the outer wall of the connecting plate 29 , and the sliding connecting plate 29 drives the tapping shaft 30 to slide synchronously, thereby realizing the elastic connection between the tapping shaft 30 and the mounting tube 27 .

[0086] A control rod 26 is slidably mounted on the inner wall of the mounting tube 27. The control rod 26 penetrates the connecting plate 29. A receiving groove is provided on the radial outer wall of the control rod 26. An elastic plate 33 is elastically mounted in the receiving groove. The elastic plate 33 is made of elastic material. Multiple elastic plates 33 are evenly arranged along the inside of the receiving groove.

[0087] The outer wall of the elastic plate 33 is fixedly installed with a locking block 32 for pressing the connecting plate 29. The sliding control rod 26 drives the elastic plate 33 and the locking block 32 to move synchronously until the locking block 32 is in contact with the side wall of the connecting plate 29. The sliding control rod 26 continues to drive the connecting plate 29 away from the mounting tube 27 through the locking block 32. At this time, the spring stores elastic potential energy, and then presses the elastic plate 33 until the locking block 32 is separated from the connecting plate 29. At this time, the spring releases the elastic potential energy, driving the tapping shaft 30 to tap the support rod 8, thereby realizing the tapping operation of the support rod 8.

[0088] The connecting plate 29 is provided with a sliding inclined groove for the locking block 32 to slide. During the reverse sliding of the control rod 26, the sliding inclined groove is provided to prevent the locking block 32 from getting stuck with the connecting plate 29 during the reverse sliding, thereby facilitating the reverse sliding of the control rod 26 and preparing for the next knocking of the support rod 8.

[0089] A telescopic cylinder 25 is fixedly mounted on the outer wall of the installation box 7 . The telescopic cylinder 25 is a common electric telescopic rod. The movable end of the telescopic cylinder 25 is fixedly connected to the outer wall of the control rod 26 . The control rod 26 is controlled to slide by the telescopic cylinder 25 .

[0090] The inner wall of the installation box 7 is installed with a pressure rod 28 for pressing the elastic plate 33 through a torsion spring rotation. One end of the pressure rod 28 extends to the inner cavity of the accommodating groove. The control rod 26 is slid until the elastic plate 33 contacts the pressure rod 28. The control rod 26 is continued to slide until the elastic plate 33 is squeezed through the pressure rod 28 to separate the locking block 32 from the connecting plate 29, thereby realizing automatic tapping of the support rod 8.

[0091] The inner wall of the mounting box 7 is provided with a mounting seat, and a pin is provided in the mounting seat. The pin passes through the pressure rod 28, and the outer wall of the pin is provided with a torsion spring. The other end of the torsion spring is fixedly connected to the pressure rod 28, so as to realize the elastic connection between the pressure rod 28 and the mounting box 7. The elastic force of the torsion spring on the pressure rod 28 is greater than the reaction force of the elastic plate 33 on the pressure rod 28 in real time, thereby ensuring that the pressure rod 28 can press the elastic plate 33.

[0092] When the support rod 8 is retracted into the installation box 7 , the outer wall of the installation tube 27 presses the pressure rod 28 to deflect the pressure rod 28 , so as to prevent the pressure rod 28 from hindering the retraction of the support rod 8 .

[0093] When the side closing formwork 5 needs to be removed, the control rod 26 is first driven to slide by the telescopic cylinder 25 until the control rod 26 extends to the inside of the support rod 8. At this time, the control rod 26 contracts, driving the connecting plate 29 to slide, and then the tapping shaft 30 is controlled by elastic force to tap the support rod 8 to facilitate the removal of the side closing formwork 5.

[0094] The above-mentioned front, back, left, right, top and bottom are all based on the figures in the specification. Figure 1 As a benchmark, according to the person's observation perspective, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0095] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present invention.

[0096] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A large direct shear apparatus for testing the horizontal shear bearing capacity of composite foundation model test, characterized by: It includes a supporting part, a control mechanism and a detection mechanism; The support portion comprises a bearing bracket (1), an upper detection mold frame (11), a lower detection mold frame (4), an upper fixed crossbeam (9) and a side closed mold frame (5), wherein the lower detection mold frame (4) is fixedly mounted on the upper end surface of the bearing bracket (1), and the upper detection mold frame (11) is arranged directly above the lower detection mold frame (4); The upper fixed crossbeam (9) passes through the upper detection mold frame (11) and has two ends fixedly connected to the side walls of the bearing bracket (1); the side closed template (5) is detachably mounted between the upper detection mold frame (11) and the lower detection mold frame (4); The detection mechanism comprises a top pressure plate (6) and a pressure sensor fixedly mounted on a side wall of the top pressure plate (6); The control mechanism comprises a control cylinder (2), a mounting box (7) and a control shaft (12); the mounting box (7) is fixedly mounted on the bearing bracket (1); the control shaft (12) is slidably mounted in the inner cavity of the mounting box (7); one end of the control shaft (12) is fixedly connected to the top pressure plate (6); the control cylinder (2) is fixedly mounted on the outer wall of the bearing bracket (1); and the sliding of the control shaft (12) is controlled by the control cylinder (2); A support rod (8) is slidably mounted inside the mounting box (7), one end of the support rod (8) passes through the top pressure plate (6) and is elastically mounted with a connecting sleeve (3), a plug-in block (10) for plugging into the connecting sleeve (3) is fixedly mounted on the outer wall of the side closed template (5), and the plug-in block (10) is fixed to the connecting sleeve (3) by plugging and fixing via a pin shaft; The movable end of the control cylinder (2) is fixedly connected to an end of the control shaft (12) away from the top pressure plate (6); a control gear (13) is rotatably mounted on the inner wall of the mounting box (7); and control racks meshing with the control gear (13) are fixedly mounted on the outer walls of the control shaft (12) and the support rod (8); The installation box (7) is provided with a receiving chamber inside, an oil guide shaft (15) is rotatably installed inside the receiving chamber, a spiral oil guide groove is provided on the radial outer wall of the oil guide shaft (15), the oil guide shaft (15) is located directly below the control gear (13), and a guide groove (18) for the flow of lubricating oil is provided on the inner wall of the control gear (13); The inner wall of the oil guide shaft (15) is rotatably mounted with a housing cylinder (19) via a torsion spring, the axial end of the control gear (13) is rotatably connected to the housing cylinder (19) via a connecting shaft, the inner cavity of the housing cylinder (19) is provided with a connecting shaft (17) fixedly connected to the axial end of the control gear (13), a control ratchet rod (20) is elastically mounted on the radial outer wall of the connecting shaft (17), and a control ratchet (24) cooperating with the control ratchet rod (20) is fixedly mounted on the inner wall of the housing cylinder (19); A bearing plate (16) is fixedly mounted on the outer wall of the mounting box (7), a plug-in shaft (23) is fixedly mounted on the upper end surface of the bearing plate (16), one end of the plug-in shaft (23) extends to the inner cavity of the oil guide shaft (15), a push rod (22) is elastically mounted on the inner wall of the plug-in shaft (23), and a resistance inclined block (21) is fixedly mounted on the inner wall of the oil guide shaft (15).

2. The large direct shear apparatus for model test of horizontal shear bearing capacity of composite foundation according to claim 1, characterized in that: The support rod (8) is made of elastic material, an elastic rod (14) is fixedly mounted on one axial end of the support rod (8), and the other end of the elastic rod (14) is fixedly connected to the connecting sleeve (3); One end of the support rod (8) away from the elastic rod (14) is fixedly connected to a mounting tube (27), and a knocking shaft (30) for knocking the support rod (8) is elastically mounted on the inner wall of the mounting tube (27).

3. The large direct shear apparatus for model test of horizontal shear bearing capacity of composite foundation according to claim 2, characterized in that: One end of the mounting tube (27) away from the support rod (8) is fixedly connected to a guide rod (31), a connecting plate (29) is slidably mounted on the outer wall of the guide rod (31), and the outer wall of the knocking shaft (30) is fixedly connected to the outer wall of the connecting plate (29).

4. The large direct shear apparatus for model test of horizontal shear bearing capacity of composite foundation according to claim 3, characterized in that: A control rod (26) is slidably mounted on the inner wall of the mounting tube (27), the control rod (26) passing through the connecting plate (29), a receiving groove is provided on the radial outer wall of the control rod (26), an elastic plate (33) is elastically mounted in the receiving groove, a locking block (32) for pressing the connecting plate (29) is fixedly mounted on the outer wall of the elastic plate (33), and a sliding inclined groove for sliding the locking block (32) is provided on one side of the connecting plate (29).

5. The large direct shear apparatus for model test of horizontal shear bearing capacity of composite foundation according to claim 4, characterized in that: A telescopic cylinder (25) is fixedly mounted on the outer wall of the installation box (7), and a movable end of the telescopic cylinder (25) is fixedly connected to the outer wall of the control rod (26); A pressure rod (28) for pressing the elastic plate (33) is rotatably mounted on the inner wall of the installation box (7) via a torsion spring, and one end of the pressure rod (28) extends to the inner cavity of the accommodating groove.

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