Visual rock-soil multi-field coupling direct shear creepmeter

Abstract

The invention provides a visual rock-soil multi-field coupling direct shear creepmeter which comprises a shear box device, a loading device, a temperature control device, a disturbance load device, a seepage control device and a microstructure tracking device, the shear box device is used for loading a rock-soil sample, the loading device comprises a normal loading device and a shear loading device, and the temperature control device is used for controlling the temperature of the normal loading device. The temperature control device comprises a dry-wet cycle device and a freeze-thaw cycle device, the disturbance load device comprises a plurality of vibration motors, the seepage control device comprises a water inlet control assembly and an electronic measuring cylinder, and the microstructure tracking device comprises a micro camera and an X-CT scanner. The visualized rock-soil multi-field coupling direct shear creepmeter provided by the invention can realize rock-soil direct shear creep tests under multi-field coupling of a dynamic seepage field, a dynamic stress field, a dynamic temperature field, a dynamic moisture field, a dynamic water chemical field and the like.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical testing equipment, in particular to a visualized rock and soil multi-field coupling direct shear creep instrument. Background Art

[0002] The creep behavior of rock and soil, that is, the slow deformation of rock and soil over time under long-term loads, is one of the important factors affecting the stability of engineering. Creep is particularly prominent in projects such as high fill slopes, deep foundation pits and tunnels. In actual engineering, rock and soil are also affected by various factors such as temperature changes, water pressure fluctuations and chemical environment. The coupling of these influencing factors will significantly affect the creep behavior of rock and soil. Therefore, studying the direct shear creep characteristics of rock and soil under multi-field coupling is of great significance for engineering design and construction.

[0003] At present, the research on shear creep characteristics of rock and soil under multi-field coupling at home and abroad is mostly based on triaxial test instruments. The sample size mostly adopts indoor test standard samples, and the gravel soil larger than 2mm is artificially removed, which seriously damages the structural property of the soil. At present, there are few direct shear creep test equipment that considers the influence of large-scale visualized multi-field coupling. The dynamic triaxial test method is mainly used for the study of creep properties of rock and soil under dynamic loads such as earthquakes, explosions, and mechanical vibrations. The study of creep properties of rock and soil under the influence of reservoir water level and rainfall mainly adopts the method of first subjecting the sample to dry-wet cycle treatment, infiltration treatment and leaching test and then creep test. The study of creep properties of rock and soil under the influence of temperature mainly adopts the method of first subjecting the sample to freeze-thaw cycle, low-temperature freezing and high-temperature treatment and then creep test. These test methods are difficult to accurately meet the actual working conditions.

[0004] In addition, the existing shear creep instrument cannot clearly observe the entire process of rock and soil shear failure, and can only observe the structure before and after the direct shear creep test. Only with the help of numerical experiments can the movement processes of particle rupture, grinding, flipping, and migration be deduced. This simulation result is difficult to verify and may be very different from the actual situation. With the occurrence of shear, the upper and lower shear boxes are offset from each other, and the center of the shear surface is displaced, causing the effective shear area to gradually decrease. The center position of the vertical normal stress applied to the upper shear box and the vertical loading force provided by the weight remain unchanged. The shear stress continues to increase with the occurrence of shear displacement, deviating from the set shear stress. For large-scale direct shear creep tests, the problem is more prominent. Therefore, the traditional direct shear creep instrument will produce distortion and errors. Summary of the invention

[0005] In order to alleviate the above problems, the present invention provides a visualized rock and soil multi-field coupling direct shear creep instrument, which realizes direct shear creep tests under multi-field coupling such as dynamic seepage field, dynamic stress field, dynamic temperature field, dynamic moisture field, and dynamic water chemical field, and has a high degree of visualization.

[0006] The present invention provides a visualized rock and soil multi-field coupling direct shear creep instrument, comprising:

[0007] A shear box device, used for loading rock and soil samples, comprises an upper shear box and a lower shear box arranged in sequence from top to bottom, wherein the upper shear box and the lower shear box are rollingly matched in the left-right direction;

[0008] A loading device, comprising a normal loading device for applying vertical compressive stress to the rock and soil sample in the shear box device and a shear loading device for applying horizontal shear stress;

[0009] The temperature control device includes a dry-wet cycle device for performing dry-wet cycle on the rock and soil samples in the shear box device, and a freeze-thaw cycle device for performing freeze-thaw cycle on the rock and soil samples in the shear box device;

[0010] a disturbance loading device, comprising a plurality of vibration motors for applying disturbances to the shear box device;

[0011] A seepage control device, comprising a water inlet control component for controlling water addition to the rock and soil sample in the shear box device and an electronic measuring cylinder for measuring the water output of the rock and soil sample in the shear box device;

[0012] The microstructure tracking device comprises a micro camera arranged outside the shear box device and an X-CT scanner arranged inside the shear box device.

[0013] According to a visualized geotechnical multi-field coupled direct shear creep instrument provided by the present invention, the upper shear box comprises four upper shear box side walls and a rectangular top cover, the four upper shear box side walls enclose an upper rectangular cavity with two ends open, the rectangular top cover is detachably arranged on the top of the upper rectangular cavity, and the four sides of the rectangular top cover can slide up and down along the inner side wall of the upper rectangular cavity;

[0014] The lower shear box includes four lower shear box side walls and a rectangular bottom plate. The four lower shear box side walls enclose a lower rectangular cavity with openings at both ends. The rectangular bottom plate is detachably arranged at the bottom of the lower rectangular cavity, and the four sides of the rectangular bottom plate can slide up and down along the inner wall of the lower rectangular cavity.

[0015] According to a visualized geotechnical multi-field coupled direct shear creep instrument provided by the present invention, the front and rear side walls of the upper shear box are respectively rollingly matched with the front and rear side walls of the lower shear box through a first ball assembly; limit baffles are installed on the outer sides of the front and rear side walls of the lower shear box, the limit baffles extend to the position of the upper shear box, and the front and rear side walls of the upper shear box can slide left and right along the two limit baffles respectively.

[0016] According to a visualized geotechnical multi-field coupled direct shear creep instrument provided by the present invention, a force transmission frame is provided on the outside of the shear box device, and the force transmission frame includes a support base plate and a support frame body fixed on the support base plate;

[0017] The bottoms of the front and rear side walls of the lower shear box are respectively rollingly matched with the support bottom plate through roller assemblies, and roller guide grooves corresponding to the roller assemblies are provided on the support bottom plate;

[0018] Lifting mechanisms are fixedly arranged at the bottom of the four corners in the lower rectangular cavity, and the rectangular bottom plate is drivingly connected to the lifting ends of the lifting mechanisms.

[0019] According to a visualized geotechnical multi-field coupling direct shear creep instrument provided by the present invention, the normal loading device includes a primary force expansion mechanism, a secondary force expansion mechanism and a limit mechanism, the primary force expansion mechanism includes a transmission chain, a transmission chain driving mechanism, a transmission toothed disc, a transmission gear, a balance gear and a transmission rack, the transmission toothed disc is installed above the transmission chain driving mechanism, the transmission chain driving mechanism is connected to the transmission chain driving, the transmission chain is meshed with the transmission toothed disc, the transmission toothed disc is coaxially installed with the transmission gear, and the transmission gear and the balance gear are respectively meshed with the two sides of the transmission rack;

[0020] The two-stage force expansion mechanism includes a first hydraulic cylinder and a second hydraulic cylinder, wherein the first hydraulic cylinder is located below the transmission rack, and the transmission rack is connected and fixed to the piston rod of the first hydraulic cylinder through a first force transmission rod; the second hydraulic cylinder is located below the force transmission frame, and the piston rod of the second hydraulic cylinder is connected and fixed to the bottom of the force transmission frame, and the oil chamber of the first hydraulic cylinder is connected to the oil chamber of the second hydraulic cylinder;

[0021] The limiting mechanism includes a gantry frame, a second force transmission rod and a pressure plate, the upper end of the second force transmission rod is connected and fixed to the top plate of the gantry frame, the lower end of the second force transmission rod is connected and fixed to the upper end surface of the pressure plate, and the lower end surface of the pressure plate is rollingly matched with the upper end surface of the rectangular top cover through a second ball assembly.

[0022] According to a visualized geotechnical multi-field coupled direct shear creep instrument provided by the present invention, the shear loading device includes a first linear drive mechanism arranged on the left side of the force transmission frame and a second linear drive mechanism arranged on the right side of the force transmission frame, the first linear drive mechanism is drivingly connected to one end of a third force transmission rod, and the other end of the third force transmission rod can contact the upper shear box to apply horizontal rightward shear stress to the upper shear box; the second linear drive mechanism is drivingly connected to one end of a fourth force transmission rod, and the other end of the fourth force transmission rod can contact the lower shear box to apply horizontal leftward shear stress to the lower shear box.

[0023] According to a visualized geotechnical multi-field coupled direct shear creep instrument provided by the present invention, a first vibration motor is drivingly connected to the bottom of the second hydraulic cylinder, a second vibration motor is drivingly connected to the left side of the first linear drive mechanism, and a third vibration motor is drivingly connected to the right side of the second linear drive mechanism.

[0024] According to a visualized geotechnical multi-field coupled direct shear creep instrument provided by the present invention, the freeze-thaw cycle device includes a first semiconductor temperature controller installed on the inner side of the upper shear box and a second semiconductor temperature controller installed on the inner side of the lower shear box.

[0025] According to a visualized rock and soil multi-field coupled direct shear creep instrument provided by the present invention, the dry-wet cycle device includes a humidifying device and a drying device, the humidifying device includes a water supply pipeline and a water pump arranged on the water supply pipeline, a plurality of water inlet holes are provided on the rectangular top cover, the water supply pipeline is detachably connected to each of the water inlet holes through a joint, a drainage hole is provided on the rectangular bottom plate, and a drainage control valve is provided on the drainage hole.

[0026] According to a visualized geotechnical multi-field coupled direct shear creep instrument provided by the present invention, the water inlet control component includes a water inlet flow sensor and a water inlet control valve arranged on the water supply pipeline; a seepage outlet hole is provided on the rectangular bottom plate, a seepage outlet control valve is provided on the seepage outlet hole, and the seepage outlet hole is detachably connected to the electronic measuring cylinder through a seepage pipeline; exhaust holes are also provided on the rectangular top cover and the rectangular bottom plate, respectively, and an exhaust control valve is provided on the exhaust hole.

[0027] The visualized geotechnical multi-field coupled direct shear creep instrument provided by the present invention integrates a shear box device, a loading device, a temperature control device, a disturbance load device, a seepage control device and a microstructure tracking device, wherein the shear box device is used to load geotechnical samples, and comprises an upper shear box and a lower shear box arranged in sequence from top to bottom, and the upper shear box and the lower shear box are rollingly matched along the left and right directions so as to apply horizontal loads in opposite directions to the upper shear box and the lower shear box respectively, so that relative displacement can occur between the upper shear box and the lower shear box; wherein the loading device comprises a normal loading device and a shear loading device, and the normal loading device is used to apply vertical compressive stress to the geotechnical samples in the shear box device, and the shear loading device is used to apply vertical compressive stress to the upper shear box and the lower shear box respectively The shear box applies horizontal shear stress; wherein the temperature control device includes a dry-wet cycle device and a freeze-thaw cycle device, the dry-wet cycle device is used to perform dry-wet cycle on the rock and soil samples in the shear box device, and the freeze-thaw cycle device is used to perform freeze-thaw cycle on the rock and soil samples in the shear box device; wherein the disturbance load device includes a plurality of vibration motors, and each vibration motor is used to apply disturbance to the shear box device; wherein the seepage control device includes a water inlet control component for controlling the water addition to the rock and soil samples in the shear box device and an electronic measuring cylinder for measuring the water output of the rock and soil samples in the shear box device; wherein the microstructure tracking device includes a micro camera arranged on the outside of the shear box device and an X-CT scanner arranged on the inside of the shear box device, so as to realize the visualization of the test process. Therefore, the visualized rock and soil multi-field coupling direct shear creep instrument provided by the present invention is suitable for rock and soil direct shear creep tests of large-scale rock and soil bodies under multi-field coupling conditions such as dynamic seepage field, dynamic stress field, dynamic temperature field, dynamic moisture field, and dynamic water chemical field, and has a high degree of visualization.

[0028] The visualized rock and soil multi-field coupled direct shear creep instrument provided by the present invention has the following beneficial effects:

[0029] The visualized rock and soil multi-field coupled direct shear creep instrument provided by the present invention is suitable for testing the creep properties of large-scale rock and soil bodies under the coupling of dynamic seepage-dynamic stress-dynamic temperature-dynamic moisture-dynamic water chemistry, and can simultaneously carry out multi-field creep tests under different normal stresses.

[0030] The visualized geotechnical multi-field coupled direct shear creep instrument provided by the present invention measures the relative displacement between the upper and lower shear boxes through a first horizontal displacement sensor and a second horizontal displacement sensor, thereby controlling the loading force of a normal loading device and keeping the vertical normal stress constant during the shearing process.

[0031] The visualized rock and soil multi-field coupled direct shear creep instrument provided by the present invention has a simple mechanical structure, is easy to adjust, and is convenient to operate. It is suitable for studying the shear creep properties of rock and soil under the action of dynamic disturbance, groundwater, chemical corrosion, dry-wet cycle, and stress alone or in combination. During the test, a chemical liquid with a certain osmotic pressure can be provided to perform regular dry-wet cycle treatment on the sample, and dynamic disturbances of different intensities, frequencies, and durations can be quantitatively simulated through simple settings.

[0032] The visualized rock and soil multi-field coupled direct shear creep instrument provided by the present invention can enable the entire process of the rock and soil dry-wet cycle test to be carried out under confined stress conditions, which is more in line with the actual situation of the project and can more intelligently and accurately control the process of each dry-wet cycle.

[0033] The visualized rock and soil multi-field coupled direct shear creep instrument provided by the present invention organically combines the rock and soil dry-wet cycle test, permeability test, direct shear creep test, freeze-thaw test, and X-CT scanning technology into the same test system, and can carry out microscopic research on the dynamic mechanical response of the rock and soil in a very systematic manner.

[0034] The present invention is equipped with an X-CT scanner for real-time scanning of the dissolution status and degree of multiple field effects such as the dry-wet cycle process and the infiltration process of the rock and soil body. It can also record the crushing and particle overturning of the front section of the rock and soil body during the direct shear creep test.

[0035] The visualized geotechnical multi-field coupled direct shear creep instrument provided by the present invention is equipped with a computer system, which can receive monitoring data and store data in real time, so as to make relevant instructions to various levels of equipment in time, perform control, and realize automation of the test process. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 It is a structural schematic diagram of the visualized rock and soil multi-field coupling direct shear creep instrument of the present invention;

[0038] Figure 2 It is a structural schematic diagram of the primary force expansion mechanism and the secondary force expansion mechanism in the visualized rock and soil multi-field coupling direct shear creep instrument of the present invention;

[0039] Figure 3 It is a structural schematic diagram of a force transmission frame and a shear box device in a visualized rock and soil multi-field coupling direct shear creep instrument of the present invention;

[0040] Figure 4 It is a schematic diagram of the coordination structure of the limit baffle and the shear box device in the visualized geotechnical multi-field coupled direct shear creep instrument of the present invention;

[0041] Figure 5 This is a schematic diagram of the structure of the humidification device in the visualized rock and soil multi-field coupled direct shear creep instrument of the present invention.

[0042] Description of reference numerals:

[0043] 1. Upper shear box; 101. Rectangular top cover; 2. Lower shear box; 201. Rectangular bottom plate; 3. First ball assembly; 4. Limit baffle; 5. Force transmission frame; 6. Roller assembly; 7. Lifting mechanism; 8. Transmission chain; 9. Transmission chain driving mechanism; 10. Transmission gear plate; 11. Transmission gear; 12. Balance gear; 13. Transmission rack; 14. First hydraulic cylinder; 15. Second hydraulic cylinder; 16. First force transmission rod; 17. Gantry frame; 18. Second force transmission rod; 19. Press plate; 2 0. Workbench; 21. Second ball assembly; 22. First linear drive mechanism; 23. Second linear drive mechanism; 24. Third force transmission rod; 25. Fourth force transmission rod; 26. First vibration motor; 27. Second vibration motor; 28. Third vibration motor; 29. ​​Water supply pipeline; 30. Water pump; 31. Drain hole; 32. Water inlet flow sensor; 33. Water inlet control valve; 35. Seepage outlet hole; 36. Seepage outlet control valve; 37. Electronic measuring cylinder; 38. Exhaust hole; 39. Exhaust control valve. DETAILED DESCRIPTION

[0044] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. 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.

[0045] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" 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, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0046] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] like Figures 1 to 5 As shown, the visualized geotechnical multi-field coupled direct shear creep instrument of the embodiment of the present invention comprises a shear box device, a loading device, a temperature control device, a disturbance load device, a seepage control device and a microstructure tracking device.

[0048] Among them, the shear box device is used to load rock and soil samples, including an upper shear box 1 and a lower shear box 2 arranged in sequence from top to bottom, and the upper shear box 1 and the lower shear box 2 are rollingly matched along the left and right directions to facilitate applying horizontal loads in opposite directions to the upper shear box 1 and the lower shear box 2 respectively, so that relative displacement can occur between the upper shear box 1 and the lower shear box 2.

[0049] Among them, the loading device includes a normal loading device and a shear loading device. The normal loading device is used to apply vertical compressive stress to the rock and soil samples in the shear box device, and the shear loading device is used to apply horizontal shear stress to the rock and soil samples in the shear box device.

[0050] Among them, the temperature control device includes a dry-wet cycle device and a freeze-thaw cycle device. The dry-wet cycle device is used to perform dry-wet cycle on the rock and soil samples in the shear box device, and the freeze-thaw cycle device is used to perform freeze-thaw cycle on the rock and soil samples in the shear box device.

[0051] The disturbance load device includes a plurality of vibration motors for applying disturbance to the shear box device.

[0052] The seepage control device includes a water inlet control component for controlling the water addition to the rock and soil samples in the shear box device and an electronic measuring cylinder 37 for measuring the water output of the rock and soil samples in the shear box device.

[0053] The microstructure tracking device includes a micro camera arranged on the outside of the shear box device and an X-CT scanner arranged on the inside of the shear box device, so as to realize the visualization of the test process.

[0054] Therefore, the visualized rock and soil multi-field coupling direct shear creep instrument of the embodiment of the present invention is suitable for direct shear creep tests of large-scale rock and soil bodies under multi-field coupling conditions such as dynamic seepage field, dynamic stress field, dynamic temperature field, dynamic moisture field, and dynamic water chemical field, and has a high degree of visualization.

[0055] Specifically, the visualized rock and soil multi-field coupling direct shear creep instrument of the embodiment of the present invention also includes a controller, which is electrically connected to the shear box device, the loading device, the temperature control device, the disturbance load device, the seepage control device and the microstructure tracking device, thereby realizing the automatic control of the direct shear creep test under multi-field coupling conditions.

[0056] Specifically, the upper shear box 1 includes four upper shear box side walls and a rectangular top cover 101. The four upper shear box side walls enclose an upper rectangular cavity with two ends open. The rectangular top cover 101 is detachably arranged on the top of the upper rectangular cavity, and the four sides of the rectangular top cover 101 can slide up and down along the inner side wall of the upper rectangular cavity. When the geotechnical sample is loaded in the shear box device, the rectangular top cover 101 is covered on the top of the geotechnical sample, and a normal stress can be applied to the geotechnical sample by applying a downward force to the rectangular top cover 101.

[0057] The lower shear box 2 includes four lower shear box side walls and a rectangular bottom plate 201. The four lower shear box side walls enclose a lower rectangular cavity with two ends open. The rectangular bottom plate 201 is detachably arranged at the bottom of the lower rectangular cavity, and the four sides of the rectangular bottom plate 201 can slide up and down along the inner side wall of the lower rectangular cavity. When the test is completed, an upward force can be applied to the rectangular bottom plate 201, so as to facilitate the rock and soil sample to be lifted up and taken out from the shear box device.

[0058] Specifically, the front and rear side walls of the upper shear box 1 are respectively rolled with the front and rear side walls of the lower shear box 2 through the first ball assembly 3, so that the upper shear box 1 and the lower shear box 2 can roll with each other in the left and right direction.

[0059] Among them, each first ball assembly 3 includes a row of first balls, and ball grooves matching the first balls are respectively provided at the bottom of the front and rear side walls of the upper shear box 1 and at the top of the front and rear side walls of the lower shear box 2 to limit the first balls from rolling in the left and right directions.

[0060] Specifically, limit baffles 4 are respectively installed on the outer sides of the front and rear side walls of the lower shear box 2, and each limit baffle 4 extends to the position of the upper shear box 1, and the front and rear side walls of the upper shear box 1 can slide left and right along the two limit baffles 4, respectively, thereby limiting the left and right movement between the upper shear box 1 and the lower shear box 2, and preventing the upper shear box 1 from being displaced forward and backward between the lower shear box 2.

[0061] Specifically, two micro cameras are provided, which can be respectively arranged on the outside of the left wall of the upper shear box 1 and the outside of the right wall of the lower shear box 2, so as to facilitate the observation of the relative displacement between the upper shear box 1 and the lower shear box 2 and the external changes of the geotechnical sample.

[0062] Among them, the installation position of the X-CT scanner inside the shear box device can be set according to actual usage requirements. The X-CT scanner can be used to observe the overall changes of the rock and soil samples during the test.

[0063] In some embodiments of the present invention, a force transmission frame 5 is provided on the outside of the shear box device, and the force transmission frame 5 includes a support bottom plate and a support frame body fixed on the support bottom plate, wherein the bottoms of the front and rear side walls of the lower shear box 2 respectively roll with the support bottom plate of the force transmission frame 5 through roller assemblies 6, and a roller guide groove that cooperates with the roller assembly 6 is also provided on the support bottom plate of the force transmission frame 5 to limit the rolling direction of the roller assembly 6. That is, by providing the roller assembly 6, it is convenient to realize the relative movement between the shear box device and the force transmission frame 5, so as not to affect the horizontal shear stress applied to the shear box device during the test.

[0064] Among them, a lifting mechanism 7 is fixedly installed at the bottom of the four corners of the lower rectangular cavity of the lower shear box 2, and the rectangular bottom plate 201 of the lower shear box 2 is driven and connected to the lifting end of the lifting mechanism 7, so that the rectangular bottom plate 201 can be driven to move up and down along the inner wall of the lower rectangular cavity, so as to push the rock and soil samples on the rectangular bottom plate 201 upward after the test is completed.

[0065] In some embodiments of the present invention, the normal loading device includes a primary force expansion mechanism, a secondary force expansion mechanism and a limiting mechanism. The primary force expansion mechanism includes a transmission chain 8, a transmission chain driving mechanism 9, a transmission sprocket 10, a transmission gear 11, a balance gear 12 and a transmission rack 13. The transmission sprocket 10 is installed on the top of the transmission chain driving mechanism 9 through a mounting frame (not shown in the figure). The transmission chain driving mechanism 9 is drivingly connected to the transmission chain 8, and the transmission chain 8 is meshingly connected to the transmission sprocket 10. The transmission gear 11 and the transmission sprocket 10 are arranged from front to back and are coaxially installed on the mounting frame. The transmission gear 11 and the balance gear 12 are respectively meshedly connected with the two sides of the transmission rack 13. A guide groove (not shown in the figure) is also provided on the mounting frame for sliding up and down with the transmission rack 13. That is, the transmission chain driving mechanism 9 can drive the transmission sprocket 10 to rotate clockwise through the transmission chain 8, and the rotation of the transmission sprocket 10 can drive the transmission gear 11 to rotate clockwise synchronously, and then the rotation of the transmission gear 11 drives the transmission rack 13 to move downward along the guide groove.

[0066] The transmission chain driving mechanism 9 adopts an existing structural form, for example, a steel wire rope of a winch can be connected to one end of the transmission chain 8, and the other end of the transmission chain 8 can be connected to the transmission gear 11, so as to drive the transmission gear 11. Alternatively, two driving motors can be provided, each motor is provided with a sprocket, and the annular transmission chain 8 is connected through the transmission gear 11 and the two sprockets, so as to drive the transmission gear 11.

[0067] The secondary force expansion mechanism includes a first hydraulic cylinder 14 and a second hydraulic cylinder 15. The first hydraulic cylinder 14 is located below the transmission rack 13, and the transmission rack 13 is connected and fixed to the piston rod of the first hydraulic cylinder 14 through the first force transmission rod 16. The second hydraulic cylinder 15 is located below the force transmission frame 5, and the piston rod of the second hydraulic cylinder 15 is connected and fixed to the bottom of the force transmission frame 5, and the oil chamber of the first hydraulic cylinder 14 is connected to the oil chamber of the second hydraulic cylinder 15. That is, when the transmission rack 13 moves downward along the guide groove, the piston rod of the first hydraulic cylinder 14 can be driven to contract through the first force transmission rod 16, thereby squeezing the oil chamber of the first hydraulic cylinder 14, so that the hydraulic oil in the first hydraulic cylinder 14 flows into the second hydraulic cylinder 15, and then the second hydraulic cylinder 15 provides a reliable upward driving force for the force transmission frame 5, thereby achieving the purpose of secondary force expansion.

[0068] The limiting mechanism includes a gantry frame 17, a second force transmission rod 18 and a pressure plate 19. The gantry frame 17 is fixedly mounted on a workbench 20, and the workbench 20 is fixedly mounted on the ground. The upper end of the second force transmission rod 18 is connected and fixed to the top plate of the gantry frame 17, and the lower end of the second force transmission rod 18 is connected and fixed to the upper end surface of the pressure plate 19. The lower end surface of the pressure plate 19 and the upper end surface of the rectangular bottom plate 201 of the lower shear box 2 are rollingly matched through the second ball assembly 21. That is, under the support of the gantry frame 17 and the second force transmission rod 18, the position of the pressure plate 19 can be ensured to remain unchanged. When the second hydraulic cylinder 15 applies an upward force to the force transmission frame 5, it can drive the shear box device on the force transmission frame 5 to move upward synchronously, and then squeeze the geotechnical sample in the shear box device through the rectangular top cover 101 under the action of the pressure plate 19, so as to achieve the purpose of applying normal stress to the geotechnical sample in the shear box device. Among them, the first-stage force expansion mechanism, the second-stage force expansion mechanism and the limiting mechanism constitute an axial pressure force expansion structure.

[0069] Among them, the second ball assembly 21 includes two rows of second balls, and two ball grooves respectively matching the two rows of second balls are provided at the bottom of the pressure plate 19 and the top of the rectangular bottom plate 201. The ball grooves extend along the left and right directions to limit the second balls from rolling along the left and right directions, ensuring that when normal stress is applied to the geotechnical specimen, horizontal loads in opposite directions can be applied to the upper shear box 1 and the lower shear box 2 at the same time.

[0070] In some embodiments of the present invention, the shear loading device includes a first linear drive mechanism 22 disposed on the left side of the force transmission frame 5 and a second linear drive mechanism 23 disposed on the right side of the force transmission frame 5. The first linear drive mechanism 22 is drivingly connected to one end of a third force transmission rod 24, and the other end of the third force transmission rod 24 can contact the upper shear box 1 to apply horizontal rightward shear stress to the upper shear box 1. The second linear drive mechanism 23 is drivingly connected to one end of a fourth force transmission rod 25, and the other end of the fourth force transmission rod 25 can contact the lower shear box 2 to apply horizontal leftward shear stress to the lower shear box 2. During the test, the horizontal loads applied by the first linear drive mechanism 22 and the second linear drive mechanism 23 are controlled to be equal in magnitude and opposite in direction.

[0071] Specifically, a first vibration motor 26 is drivingly connected to the bottom of the second hydraulic cylinder 15, a second vibration motor 27 is drivingly connected to the left side of the first linear drive mechanism 22, and a third vibration motor 28 is drivingly connected to the right side of the second linear drive mechanism 23, for applying disturbance to the shear box device.

[0072] Specifically, an axial pressure sensor is provided at the bottom of the rectangular top cover 101 for detecting axial pressure data. A first horizontal pressure sensor is installed at the other end of the third force transmission rod 24 for detecting the horizontal rightward shear stress data received by the upper shear box 1. A second horizontal pressure sensor is installed at the other end of the fourth force transmission rod 25 for detecting the horizontal leftward shear stress data received by the lower shear box 2. In addition, an axial displacement sensor for detecting the axial displacement of the rectangular top cover 101, a first horizontal displacement sensor for detecting the horizontal displacement of the upper shear box 1, and a second horizontal displacement sensor for detecting the horizontal displacement of the lower shear box 2 are also installed on the geotechnical multi-field coupled direct shear creep instrument of the embodiment of the present invention.

[0073] In some embodiments of the present invention, the freeze-thaw cycle device includes a first semiconductor temperature controller installed on the inner side of the upper shear box 1 and a second semiconductor temperature controller installed on the inner side of the lower shear box 2, and the first semiconductor temperature controller and the second semiconductor temperature controller have the same structure.

[0074] Among them, the first semiconductor temperature controller includes a semiconductor refrigeration plate (not shown in the figure) arranged on the inner wall of the upper shear box 1, the semiconductor refrigeration plate is fixedly connected to the aluminum plate (not shown in the figure), the semiconductor refrigeration plate is electrically connected to the power supply, the aluminum plate is used to contact the rock and soil sample, and the aluminum plate serves as a heat transfer medium between the semiconductor refrigeration plate and the rock and soil sample to heat / cool the rock and soil sample.

[0075] Since the semiconductor temperature controller used in this embodiment is an existing structure, the other structures of the semiconductor temperature controller are not described in detail. The temperature change rate of the semiconductor refrigeration chip can reach 0.2°C / s, and the temperature change range of the semiconductor refrigeration chip is -40°C to 60°C, so it can meet the freeze-thaw cycle test requirements in this embodiment.

[0076] A temperature sensor is also provided inside the shear box device to detect the temperature data of the rock and soil sample. The specific installation position of the temperature sensor can be set according to actual use requirements.

[0077] In some embodiments of the present invention, the dry-wet cycle device includes a humidifying device and a drying device, wherein the humidifying device includes a water supply pipeline 29 and a water pump 30 arranged on the water supply pipeline 29, a plurality of water inlet holes are arranged on the rectangular top cover 201, the water supply pipeline 29 is detachably connected to each water inlet hole through a joint, a drainage hole 31 is arranged on the rectangular bottom plate 201, and a drainage control valve 32 is arranged on the drainage hole 31. The water supply pipeline 29 can be used to supply water to the soil sample in the shear box device for humidification, and the drainage hole 31 can be used to drain the shear box device.

[0078] The drying device may adopt the heating function of the semiconductor temperature controller mentioned above, and electric heating wires may be respectively arranged in the rectangular top cover 101 and the rectangular bottom plate 201 to improve the heating and drying effect of the rock and soil samples.

[0079] In some embodiments of the present invention, the water inlet control component includes a water inlet flow sensor 33 and a water inlet control valve 34 arranged on the water supply pipeline 29. The water inlet flow sensor 33 can detect the water inlet flow of the water supply pipeline 29, thereby obtaining the amount of water added to the rock and soil sample.

[0080] A seepage hole 35 is provided on the rectangular bottom plate 201, a seepage control valve 36 is provided on the seepage hole 35, and the seepage hole 35 is detachably connected to an electronic measuring cylinder 37 through a seepage pipeline. That is, the seepage water of the rock and soil sample can be measured through the electronic measuring cylinder 37.

[0081] In addition, exhaust holes 38 are respectively provided on the rectangular top cover 101 and the rectangular bottom plate 201 , and exhaust control valves 39 are respectively provided on each exhaust hole 38 .

[0082] Specifically, a weight detection device is also provided on the rectangular bottom plate 201 for detecting the weight of the rock and soil sample.

[0083] The process of conducting a direct shear creep test using the large-scale visualized geotechnical multi-field coupled direct shear creep instrument of the embodiment of the present invention is as follows:

[0084] ① Determine the magnitude of vertical compressive stress and horizontal shear stress according to the test plan;

[0085] ② Place the prepared rock and soil sample in the lower shear box, install the upper shear box on the lower shear box, install the rectangular top cover, and turn on the microstructure tracking device;

[0086] ③ Calculate the size of the vertical load to be applied (preset value), which is the force-bearing area multiplied by the vertical compressive stress value. Adjust the load size applied by the normal loading device, and make the load reach the preset value through the axial pressure expansion structure;

[0087] ④ Calculate the size of the shear load to be applied, that is, the force-bearing area multiplied by the horizontal shear stress value. When the vertical load is applied to the preset value, the horizontal shear load is applied step by step, and the direct shear creep test is started, and finally the relevant test data is obtained;

[0088] ⑤ After the test, the lifting mechanism is used to drive the rectangular bottom plate to rise, and the rock and soil sample in the shear box device is pushed upward to remove the sample.

[0089] The process of using the large-scale visualized rock and soil multi-field coupled direct shear creep instrument of the embodiment of the present invention to conduct a direct shear creep test under water chemical seepage conditions is as follows:

[0090] ① Place the prepared rock and soil sample in the lower shear box, install the upper shear box on the lower shear box, then install the rectangular top cover, and turn on the microstructure tracking device;

[0091] ② Set the composition, concentration, temperature, water pressure and penetration time of the seepage solution according to the test plan;

[0092] ③ Open the water inlet control valve on the water supply pipeline and the seepage water outlet control valve on the seepage water outlet hole respectively, and record the water output detected by the electronic measuring cylinder at a fixed time to calculate the permeability coefficient;

[0093] ④ According to the test plan, calculate the size of the vertical load to be applied (preset value), that is, the force-bearing area multiplied by the vertical compressive stress value. Adjust the load size applied by the normal loading device, and make the load reach the preset value through the axial pressure expansion structure;

[0094] ⑤ Calculate the size of the shear load to be applied, that is, the force-bearing area multiplied by the horizontal shear stress value. When the vertical load is applied to the preset value, the horizontal shear load is applied step by step, and the direct shear creep test is started, and finally the relevant test data is obtained;

[0095] ⑥ After the test, the lifting mechanism is used to drive the rectangular bottom plate to rise, and the rock and soil samples in the shear box device are pushed upward to remove the samples.

[0096] The process of using the large-scale visualized geotechnical multi-field coupled direct shear creep instrument of the embodiment of the present invention to conduct a direct shear creep test under hydrochemical dry-wet cycle conditions is as follows:

[0097] ① Place the prepared rock and soil sample in the lower shear box, install the upper shear box on the lower shear box, then install the rectangular top cover, and turn on the microstructure tracking device;

[0098] ② Set the solution composition, concentration, temperature, water pressure and humidification time according to the test plan;

[0099] ③Open the water inlet control valve on the water supply pipeline and the seepage water outlet control valve on the seepage water outlet hole, and measure the water output regularly with an electronic measuring cylinder. After a certain period of steady-state seepage, close the water inlet control valve and the humidification process ends;

[0100] ④ After the humidification process is completed, open the drying device and each exhaust control valve. When the weight detection equipment measures that the sample mass reaches the preset value, the drying device is automatically closed and the dehumidification process is completed;

[0101] ⑤ Steps ②-④ are a complete dry-wet cycle process, and the dry-wet cycle process is repeated a certain number of times according to the test plan;

[0102] ⑥ After the dry-wet cycle is completed, calculate the vertical load size (preset value) to be applied according to the test plan, that is, the force-bearing area multiplied by the vertical compressive stress value. Adjust the load size applied by the normal loading device, and make the load reach the preset value through the axial pressure expansion structure;

[0103] ⑦ Calculate the size of the shear load to be applied, that is, the force-bearing area multiplied by the horizontal shear stress value. When the vertical load is applied to the preset value, the horizontal shear load is applied step by step, and the direct shear creep test is started, and finally the relevant test data is obtained;

[0104] ⑧After the test, the lifting mechanism is used to drive the rectangular bottom plate to rise, and the rock and soil sample in the shear box device is pushed out upward to remove the sample.

[0105] The process of using the large-scale visualized geotechnical multi-field coupled direct shear creep instrument of the embodiment of the present invention to conduct a direct shear creep test under freeze-thaw cycle conditions is as follows:

[0106] ① Place the prepared rock and soil sample in the lower shear box, install the upper shear box on the lower shear box, then install the rectangular top cover, and turn on the microstructure tracking device;

[0107] ② Set the heating temperature, heating time, freezing temperature and freezing time of each semiconductor thermostat according to the test plan;

[0108] ③ Freeze the rock and soil samples through a semiconductor temperature controller, heat and melt them after the freezing time is set, and heat them for the set time to completely melt the samples;

[0109] ④ Steps ②-③ are a complete freeze-thaw cycle process, and the freeze-thaw cycle process is repeated a certain number of times according to the test plan;

[0110] ⑤ After the freeze-thaw cycle is over, calculate the vertical load size (preset value) to be applied according to the test plan, that is, the force-bearing area multiplied by the vertical compressive stress value. Adjust the load size applied by the normal loading device, and make the load reach the preset value through the axial pressure expansion structure;

[0111] ⑥ Calculate the size of the shear load to be applied, that is, the force-bearing area multiplied by the horizontal shear stress value. When the vertical load is applied to the preset value, the horizontal shear load is applied step by step, and the direct shear creep test is started, and finally the relevant test data is obtained;

[0112] ⑦ After the test, the lifting mechanism is used to drive the rectangular bottom plate to rise, and the rock and soil samples in the shear box device are pushed out upward to remove the samples.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A visualized rock and soil multi-field coupling direct shear creep instrument, characterized in that: include: A shear box device, used for loading rock and soil samples, comprises an upper shear box and a lower shear box arranged in sequence from top to bottom, wherein the upper shear box and the lower shear box are rollingly matched in the left-right direction; A loading device, comprising a normal loading device for applying vertical compressive stress to the rock and soil sample in the shear box device and a shear loading device for applying horizontal shear stress; The temperature control device includes a dry-wet cycle device for performing dry-wet cycle on the rock and soil samples in the shear box device, and a freeze-thaw cycle device for performing freeze-thaw cycle on the rock and soil samples in the shear box device; a disturbance loading device, comprising a plurality of vibration motors for applying disturbances to the shear box device; A seepage control device, comprising a water inlet control component for controlling water addition to the rock and soil sample in the shear box device and an electronic measuring cylinder for measuring the water output of the rock and soil sample in the shear box device; The microstructure tracking device comprises a micro camera arranged outside the shear box device and an X-CT scanner arranged inside the shear box device.

2. The visualized geotechnical multi-field coupled direct shear creep instrument according to claim 1 is characterized in that: The upper shear box includes four upper shear box side walls and a rectangular top cover, the four upper shear box side walls enclose an upper rectangular cavity with two ends open, the rectangular top cover is detachably arranged on the top of the upper rectangular cavity, and the four sides of the rectangular top cover can slide up and down along the inner side wall of the upper rectangular cavity; The lower shear box includes four lower shear box side walls and a rectangular bottom plate. The four lower shear box side walls enclose a lower rectangular cavity with openings at both ends. The rectangular bottom plate is detachably arranged at the bottom of the lower rectangular cavity, and the four sides of the rectangular bottom plate can slide up and down along the inner wall of the lower rectangular cavity.

3. The visualized rock and soil multi-field coupling direct shear creep instrument according to claim 2 is characterized in that: The front and rear side walls of the upper shear box are respectively rollingly matched with the front and rear side walls of the lower shear box through the first ball assembly; limit baffles are installed on the outer sides of the front and rear side walls of the lower shear box, and the limit baffles extend to the position of the upper shear box, and the front and rear side walls of the upper shear box can slide left and right along the two limit baffles respectively.

4. The visualized geotechnical multi-field coupled direct shear creep instrument according to claim 2 is characterized in that: A force transmission frame is provided on the outside of the shear box device, and the force transmission frame includes a support base plate and a support frame body fixed on the support base plate; The bottoms of the front and rear side walls of the lower shear box are respectively rollingly matched with the supporting bottom plate through roller assemblies, and roller guide grooves corresponding to the roller assemblies are provided on the supporting bottom plate; Lifting mechanisms are fixedly arranged at the bottom of the four corners in the lower rectangular cavity, and the rectangular bottom plate is drivingly connected to the lifting ends of the lifting mechanisms.

5. The visualized geotechnical multi-field coupled direct shear creep instrument according to claim 4 is characterized in that: The normal loading device includes a primary force expansion mechanism, a secondary force expansion mechanism and a limiting mechanism. The primary force expansion mechanism includes a transmission chain, a transmission chain driving mechanism, a transmission toothed disc, a transmission gear, a balance gear and a transmission rack. The transmission toothed disc is installed above the transmission chain driving mechanism. The transmission chain driving mechanism is connected to the transmission chain in driving connection. The transmission chain is meshed with the transmission toothed disc. The transmission toothed disc is coaxially installed with the transmission gear. The transmission gear and the balance gear are respectively meshed with the two sides of the transmission rack. The two-stage force expansion mechanism includes a first hydraulic cylinder and a second hydraulic cylinder, wherein the first hydraulic cylinder is located below the transmission rack, and the transmission rack is connected and fixed to the piston rod of the first hydraulic cylinder through a first force transmission rod; the second hydraulic cylinder is located below the force transmission frame, and the piston rod of the second hydraulic cylinder is connected and fixed to the bottom of the force transmission frame, and the oil chamber of the first hydraulic cylinder is connected to the oil chamber of the second hydraulic cylinder; The limiting mechanism includes a gantry frame, a second force transmission rod and a pressure plate, the upper end of the second force transmission rod is connected and fixed to the top plate of the gantry frame, the lower end of the second force transmission rod is connected and fixed to the upper end surface of the pressure plate, and the lower end surface of the pressure plate is rollingly matched with the upper end surface of the rectangular top cover through a second ball assembly.

6. The visualized geotechnical multi-field coupled direct shear creep instrument according to claim 5 is characterized in that: The shear loading device comprises a first linear drive mechanism arranged on the left side of the force transmission frame and a second linear drive mechanism arranged on the right side of the force transmission frame, wherein the first linear drive mechanism is drivingly connected to one end of a third force transmission rod, and the other end of the third force transmission rod can contact the upper shear box to apply horizontal rightward shear stress to the upper shear box; The second linear drive mechanism is drivingly connected to one end of a fourth force transmission rod, and the other end of the fourth force transmission rod can be in contact with the lower shear box to apply horizontal leftward shear stress to the lower shear box.

7. The visualized geotechnical multi-field coupled direct shear creep instrument according to claim 6 is characterized in that: A first vibration motor is drivingly connected to the bottom of the second hydraulic cylinder, a second vibration motor is drivingly connected to the left side of the first linear drive mechanism, and a third vibration motor is drivingly connected to the right side of the second linear drive mechanism.

8. The visualized rock and soil multi-field coupling direct shear creep instrument according to claim 1 is characterized in that: The freeze-thaw cycle device includes a first semiconductor temperature controller installed on the inner side of the upper shear box and a second semiconductor temperature controller installed on the inner side of the lower shear box.

9. The visualized geotechnical multi-field coupled direct shear creep instrument according to claim 2 is characterized in that: The dry-wet cycle device includes a humidifying device and a drying device. The humidifying device includes a water supply pipeline and a water pump arranged on the water supply pipeline. A plurality of water inlet holes are provided on the rectangular top cover. The water supply pipeline is detachably connected to each of the water inlet holes through a joint. A drainage hole is provided on the rectangular bottom plate, and a drainage control valve is provided on the drainage hole.

10. The visualized geotechnical multi-field coupled direct shear creep instrument according to claim 9, characterized in that: The water inlet control component includes a water inlet flow sensor and a water inlet control valve arranged on the water supply pipeline; a seepage outlet hole is provided on the rectangular bottom plate, a seepage outlet control valve is provided on the seepage outlet hole, and the seepage outlet hole is detachably connected to the electronic measuring cylinder through a seepage pipeline; exhaust holes are also provided on the rectangular top cover and the rectangular bottom plate respectively, and an exhaust control valve is provided on the exhaust hole.

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