A structural interface direct shear-seepage test device and method considering fluid viscosity

Abstract

The present invention discloses a direct shear-seepage test device and method for a structural interface that takes fluid viscosity into consideration. The device comprises a direct shear loading system, a seepage system, and a load control and data acquisition system. The direct shear loading system is used to apply normal loading force and tangential shear force to a structural sample and a bulk material sample to conduct a direct shear loading test, and a sealing chamber is arranged to achieve fluid sealing of the shear box during the test; the seepage system is used to inject fluid into the structural interface between the structural sample and the bulk material sample to conduct a seepage test; and the load control and data acquisition system is used to adjust the normal loading force, tangential shear force, and pore water pressure, as well as to collect test data. The present invention can not only effectively seal the process of a direct shear-seepage test, ensuring sealing stability during a seepage test under high osmotic water pressure, but can also use fluids of different viscosities to conduct seepage tests, thereby providing data support for exploring the direct shear-seepage characteristics of structural interfaces of different geotechnical materials.

Description

Technical Field

[0001] The present invention relates to a direct shear-seepage test device and method, in particular to a structural interface direct shear-seepage test device and method considering fluid viscosity, belonging to the technical field of geotechnical engineering. Background Art

[0002] During infrastructure construction, pile foundations are often driven into weak, water-bearing soils. Friction piles rely on the interfacial properties of the piles with the soil. During well construction, understanding the mechanical properties of the interface between the frozen wall and the surrounding soil is crucial for safe well construction. During underwater pouring, the interfacial properties between the bulk concrete in the slurry and the formwork are crucial to the success of the project. Under water-bearing conditions, the stress transfer and deformation characteristics between various structures are profoundly affected by water pressure and fluid properties. Therefore, in-depth research on the shear-seepage characteristics of interfaces between different structures (soil, concrete, rock, steel) can provide theoretical support for various geotechnical engineering projects.

[0003] At present, there are few studies on the direct shear-seepage coupling characteristics of structural interfaces in the industry, and no research considering the influence of fluid properties (i.e., fluid viscosity) on interface characteristics has been found. The invention patent with publication number CN 102253183 A, entitled “A rock fracture shear seepage coupling test system under confining pressure”, proposes a rock fracture shear seepage coupling test system that can realize rock fracture permeability testing and analysis under complex stress states; the utility model patent with announcement number CN202133661U, entitled “Rock fracture shear seepage coupling test box”, can ensure that during the shear process of rock joints, when the upper and lower joint surfaces produce relative displacement under the action of shear force, the water in the rock joints flows along a specified path, and no water leakage occurs on the boundary perpendicular to the water flow direction; in addition, the invention patent with publication number CN 114235601 A, entitled “A soil-rock interface direct shear-seepage test device and test method under constant normal stress conditions”, can impose constant normal stress conditions on soil-rock specimens and realize the direct shear-seepage process of the test object.

[0004] The above schemes can all realize the direct shear-seepage process under certain conditions, but all of the above schemes have the same problem that cannot be solved: the most difficult problem to solve in conducting interfacial direct shear-seepage research is the dynamic sealing problem of the test process, that is, it is difficult to ensure that the fluid only flows in the contact interface during the shear displacement of the specimen and does not leak from the side of the shear box. The various existing schemes mainly seal the shear box itself. Since the shear box needs to apply shear force to it from the outside to perform a direct shear test on the specimen inside, the sealing material of the shear box is generally made of flexible materials such as silicone rubber to ensure the smooth transmission of the shear force. However, this material is very easy to deform, and the deformation of the shear box during the shear process will generate friction resistance between it and the specimen, which will not only affect the test, but also may cause the seal to fail; on the other hand, this method is a dynamic sealing method (that is, the sealing body is in the process of moving or deforming); this method has a low sealing pressure, so it is difficult to carry out seepage tests with high permeability water pressure, otherwise the shear box is prone to leakage.

[0005] In summary, how to provide a new test device and method that can not only effectively seal the direct shear-seepage test process and ensure the sealing stability during the seepage test with high permeability water pressure; but also use fluids of different viscosities to conduct seepage tests, thereby providing data support for exploring the direct shear-seepage characteristics of the structural interfaces of different geotechnical materials, is the research direction of this invention. Summary of the Invention

[0006] In response to the problems existing in the above-mentioned prior art, the present invention provides a direct shear-seepage test device and method for a structural interface that takes into account the viscosity of the fluid. The device and method can not only effectively seal the direct shear-seepage test process and ensure the sealing stability during the seepage test under high osmotic water pressure, but also can use fluids of different viscosities to conduct seepage tests, thereby providing data support for exploring the direct shear-seepage characteristics of the structural interfaces of different geotechnical materials.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a structural interface direct shear-seepage test device considering fluid viscosity, including a direct shear loading system, a seepage system and a load control and data acquisition system. The direct shear loading system is used to apply normal loading force and tangential shear force to the structural sample and the bulk material sample to perform a direct shear loading test; the seepage system is used to inject fluid into the structural interface between the structural sample and the bulk material sample to perform a seepage test; the load control and data acquisition system is used to adjust the normal loading force, tangential shear force and the pressure of the injected fluid. The direct shear loading system also includes a sealing chamber.

[0008] The sealing chamber includes a lower sealing shell and two small sealing shells, the two small sealing shells are fixedly connected to form an upper sealing shell, the upper sealing shell is located above the lower sealing shell, and the two are fixedly connected to form a sealing chamber; grooves are provided on the contact surfaces of the two small sealing shells and the contact surfaces of the upper sealing shell and the lower sealing shell, and sealing belts are installed in the grooves to seal each contact surface; the shear box of the direct shear loading system is placed in the sealing chamber, and a liquid injection hole, a fluid inlet, a first loading port, an exhaust hole and a wire hole are provided on the upper part of the sealing chamber, wherein the liquid injection hole is used for the liquid injection pipeline of the seepage system to be connected to the shear box through the liquid injection hole; the fluid inlet is used to fill the sealing chamber with liquid related to the seepage system when conducting a direct shear-seepage test. The same fluid as the injection fluid is used to achieve sealing of the shear box; the first loading port is used for the normal jack in the direct shear loading system to apply normal loading force to the shear box through the first loading port; the exhaust hole is used to discharge internal air when the fluid is injected into the sealing chamber; the wire hole is used for the wires of the load control and data acquisition system to extend into the sealing chamber through the wire hole; the side of the sealing chamber is provided with a second loading port, a seepage outlet hole and a waste liquid outlet, the second loading port is used for the tangential jack in the direct shear loading system to apply tangential shear force to the shear box through the second loading port; the seepage outlet hole is used for the fluid injected into the shear box by the seepage system to be discharged from the seepage outlet hole through a pipeline; the waste liquid outlet is used for the fluid in the sealing chamber to be discharged from the sealing chamber through the waste liquid outlet after the test is completed.

[0009] Furthermore, the direct shear loading system includes a loading frame, a shear box, a normal jack and a tangential jack. The sealed chamber is fixed to the inside of the loading frame by an integral fixing bolt. The shear box includes an upper box body and a lower box body. The shear box is made of a flexible material. The lower box body is fixed in the sealed chamber by a first positioning pin. The upper box body is located on the upper part of the lower box body and the two are fixedly connected by a second positioning pin. The structural sample is placed in the lower box body, and the bulk material sample is placed in the upper box body. A structural interface is formed between the structural sample and the bulk material sample. Infiltration holes and drainage holes are respectively provided on both sides of the shear box on the same horizontal plane of the interface. The fixed end of the normal jack is fixedly connected to the loading frame and is located above the sealing chamber. The protruding end of the normal jack extends into the sealing chamber through the first loading port; the protruding end is provided with a loading plate, and the loading plate is provided with a roller for applying a normal loading force to the shear box; the fixed end of the tangential jack is fixedly connected to the loading frame and is located on the side of the sealing chamber. The protruding end of the tangential jack extends into the sealing chamber through the second loading port, and is used to apply a tangential shear force to the upper box body.

[0010] Furthermore, the seepage system includes a seepage hydraulic pump, a fluid changer, a seepage fluid cartridge and a waste fluid cartridge, the seepage fluid cartridge is used to hold the fluid injected for the seepage test; the inlet of the fluid changer is connected to the seepage fluid cartridge so that the fluid in the seepage fluid cartridge flows into the fluid changer, and the outlet of the fluid changer is connected to the seepage inlet of the shear box through a seepage fluid conduit; the seepage hydraulic pump is connected to the drive port of the fluid changer, and when the seepage hydraulic pump is started, it can drive the fluid in the fluid changer to pass through the seepage inlet at a certain pressure and be injected between the structural interfaces to perform a seepage test; the drainage hole is connected to the waste fluid cartridge through a pipeline, and the waste liquid outlet is connected to the waste liquid cartridge through a waste liquid conduit. The waste liquid cartridge is used to discharge the fluid that passes through the structural interface after the seepage test and the fluid in the sealed chamber to the waste liquid cartridge for recovery.

[0011] Furthermore, a control valve is installed on the pipeline between the seepage hydraulic pump and the fluid changer to control the on-off connection between the seepage hydraulic pump and the fluid changer; a one-way valve is installed on the pipeline between the seepage fluid cylinder and the fluid changer, the seepage fluid conduit, the pipeline between the drainage hole and the waste liquid cylinder, and the waste liquid conduit to control the one-way flow of the fluid and prevent backflow from affecting the test.

[0012] Furthermore, each side wall of the seepage liquid cartridge and the waste liquid cartridge is provided with scales, so as to facilitate reading the amount of fluid in each of the seepage liquid cartridge and the waste liquid cartridge.

[0013] Furthermore, the load control and data acquisition system includes a load controller, a data acquisition device and two load sensors. The two load sensors are respectively installed on the protruding ends of the normal jack and the tangential jack, and are used to monitor the normal loading force and tangential shear force applied by the normal jack and the tangential jack to the shear box respectively, and feed back to the data acquisition device for storage. The load controller is respectively connected to the normal jack, the tangential jack and the seepage hydraulic pump, and is used to control the pressure output by the normal jack and the tangential jack, and the injection pressure output by the seepage hydraulic pump.

[0014] Furthermore, the two small sealed shells are detachably fixedly connected by horizontal fixing bolts, and the upper sealed shell and the lower sealed shell are detachably fixedly connected by vertical fixing bolts. This structure not only provides a stable connection but also facilitates disassembly and installation.

[0015] The test method of the structural interface direct shear-seepage test device considering fluid viscosity has the following specific steps:

[0016] Step 1: Prepare a structural sample (including but not limited to rock, concrete, and steel) and a bulk material sample (including but not limited to soil, mortar, and gravel), saturate both samples, and then prepare the seepage fluid (including but not limited to water, chemical solution, and mud), determine the viscosity of the fluid, and set the pressure output by the normal jack and the tangential jack, as well as the injection pressure output by the seepage hydraulic pump;

[0017] Step 2: Fix the lower sealed shell on the loading frame and place the shear box in the sealed chamber. Then place the structure sample prepared in step 1 in the lower box body and the bulk material sample in the upper box body. Finally, fix the upper box body and the lower box body together to complete the shear box installation. Fix the two small sealed shells together to form the upper sealed shell. Finally, place the upper sealed shell on top of the lower sealed shell for fixed sealing.

[0018] Step 3: Assemble the direct shear loading system, seepage system, and the rest of the load control and data acquisition system in sequence;

[0019] Step 4: After assembly is completed, the waste liquid outlet is blocked, and the fluid used for the seepage configured in step 1 is injected into the sealing chamber through the fluid inlet, and the shear box is ensured to be completely immersed in the fluid to achieve static sealing of the shear box;

[0020] Step 5: The load controller controls the normal jack to apply pressure, and monitors the normal loading force applied by the load sensor in real time to reach the predetermined value and maintain it. Then, the load controller controls the tangential jack to apply shear stress, and monitors the tangential shear force applied by the load sensor in real time to reach the predetermined value and maintain it. Then, the load controller controls the start of the seepage hydraulic pump, and the seepage hydraulic pump injects the fluid in the commutator into the shear box at the set grouting pressure to start the structural interface direct shear-seepage test. During the test, the shear box is completely immersed in the fluid, and the fluid in the sealing chamber is exactly the same as the fluid injected by the seepage, thereby ensuring the sealing effect during the test.

[0021] Step 6: After the test is completed, the amount of fluid discharged from the drain hole is obtained through the waste liquid cylinder, and the amount of fluid injected into the shear box is obtained. The data is stored in the data acquisition device, and the viscosity of the fluid in this test, the set pressure output by the normal jack and the tangential jack, and the injection pressure output by the seepage hydraulic pump are stored; finally, the waste liquid outlet is opened to discharge the fluid in the sealed chamber, completing the entire test process;

[0022] Step 7. Prepare different structural samples, different bulk material samples, and fluids of different viscosities, and set different pressures output by the normal jack and tangential jack, as well as different injection pressures output by the seepage hydraulic pump; repeat steps 1 to 6 respectively, so as to obtain the corresponding direct shear-seepage test data under different conditions.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. The present invention arranges a sealing chamber with a specific structure and fixes the shear box in the sealing chamber. Before the test starts, the sealing chamber is filled with a fluid with the same properties as that used for seepage, and the shear box is completely immersed in the fluid, which is equivalent to sealing with a homogeneous fluid. Compared with the use of flexible sealing materials, it will not produce friction on the direct shear box, and the test results are more accurate; and when the direct shear-seepage test is carried out subsequently, the dynamic sealing problem of the direct shear test that is difficult to solve in the prior art is converted into a static seal of the fluid in the sealing chamber, which greatly reduces the difficulty of the test sealing and can ensure the sealing effect during the test.

[0025] 2. Since the present invention adopts a fluid static sealing method in a sealed chamber, it is easier to carry out seepage tests with high permeability water pressure and obtain corresponding test data, providing data support for subsequent research on the direct shear-seepage characteristics of the structural interface of different geotechnical materials.

[0026] 3. During the test, the present invention can adjust the seepage pressure as needed, thereby simulating working conditions with higher seepage pressure; and the seepage fluid can select fluids of different viscosities according to the actual situation on site, so that the test is more consistent with the on-site conditions. By matching the pressure and viscosity with the actual working conditions during the test, the accuracy of the test data obtained under the actual on-site working conditions is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the test device in the present invention;

[0028] Figure 2 yes Figure 1 Schematic diagram of the partial enlarged structure of the middle shear box and sealing chamber.

[0029] In the figure: 1-loading frame, 2-sealing chamber, 3-vertical fixing bolt, 4-integral fixing bolt, 5-sealing belt, 6-horizontal fixing bolt, 7-liquid injection hole, 8-wire hole, 9-waste liquid outlet, 10-air vent, 11-fluid inlet, 12-permeation outlet, 13-first positioning pin, 14-permeation hole, 15-second positioning pin, 16-shear box, 17-loading plate, 18-roller, 19-drainage hole, 20-loading Load sensor, 21-normal jack, 22-jack fixing bolt, 23-tangential jack, 24-seepage hydraulic pump, 25-fluid exchanger, 26-seepage liquid cylinder, 27-seepage liquid conduit, 28-control valve, 29-wire, 30-load controller, 31-waste liquid conduit, 32-waste liquid cylinder, 33-data acquisition equipment, 34-check valve, 35-structural specimen, 36-bulk material specimen, 37-structural interface. DETAILED DESCRIPTION

[0030] The present invention will be further described below.

[0031] like Figure 1 As shown, a structural interface direct shear-seepage test device considering fluid viscosity includes a direct shear loading system, a seepage system, and a load control and data acquisition system. The direct shear loading system is used to apply normal loading force and tangential shear force to the structural sample and the bulk material sample to perform a direct shear loading test; the seepage system is used to inject fluid into the structural interface 37 between the structural sample 35 and the bulk material sample 36 to perform a seepage test; the load control and data acquisition system is used to adjust the normal loading force, tangential shear force, and the pressure of the injected fluid. The direct shear loading system also includes a sealing chamber 2.

[0032] like Figure 2 As shown, the sealing chamber 2 includes a lower sealing shell and two small sealing shells, the two small sealing shells are fixedly connected to form an upper sealing shell, the upper sealing shell is placed on the upper part of the lower sealing shell, and the two are fixedly connected to form the sealing chamber 2; grooves are provided on the contact surfaces of the two small sealing shells and the contact surfaces of the upper sealing shell and the lower sealing shell, and sealing tapes 5 are installed in the grooves for sealing each contact surface; the shear box 16 of the direct shear loading system is placed in the sealing chamber, and an injection hole 7, a fluid inlet 11, a first loading port, an exhaust hole 10 and a wire hole 8 are provided on the upper part of the sealing chamber 2, wherein the injection hole 7 is used for the injection pipeline of the seepage system to be connected to the shear box 16 through the injection hole 7; the fluid inlet 11 is used to fill the sealing chamber 2 with the same fluid as that used for injection of the seepage system when conducting a direct shear-seepage test, so as to achieve sealing of the shear box; the first loading port is used for direct shear loading In the shear loading system, the normal jack 21 applies a normal loading force to the shear box 16 through the first loading port; the exhaust hole 10 is used to exhaust the internal air when the fluid is injected into the sealed chamber 2; the wire hole 8 is used for the wires of the load control and data acquisition system to extend into the sealed chamber 2 through the wire hole 8; the side of the sealed chamber 2 is provided with a second loading port, a seepage outlet hole 12 and a waste liquid outlet 9, the second loading port is used for the tangential jack 23 in the direct shear loading system to apply a tangential shear force to the shear box 16 through the second loading port; the seepage outlet hole is used for the fluid injected into the shear box by the seepage system to be discharged from the seepage outlet hole through the pipeline; the waste liquid outlet 9 is used for the fluid in the sealed chamber 2 to be discharged from the sealed chamber 2 through the waste liquid outlet 9 after the test is completed; the two small sealed shells are detachably fixedly connected by a horizontal fixing bolt 6; the upper sealed shell and the lower sealed shell are detachably fixedly connected by a vertical fixing bolt 3. This structure is not only stable in connection, but also easy to disassemble and install.

[0033] The direct shear loading system includes a loading frame 1, a shear box 16, a normal jack 21 and a tangential jack 23. The sealed chamber 2 is fixed to the inside of the loading frame 1 by an integral fixing bolt 4. The shear box 16 includes an upper box body and a lower box body. The shear box 16 is made of a flexible material. The lower box body is fixed to the sealed chamber 2 by a first positioning pin 13. The upper box body is located on the upper part of the lower box body and the two are fixedly connected by a second positioning pin 15. A structural sample 35 is placed in the lower box body, and a bulk material sample 36 is placed in the upper box body. A structural interface 37 is formed between the structural sample 35 and the bulk material sample 36; and the structural interface 37 is formed between the structural sample 35 and the bulk material sample 36. Infiltration holes 14 and drainage holes 19 are respectively provided on both sides of the shear box 16 on the same horizontal plane. The fixed end of the normal jack 21 is fixedly connected to the loading frame 1 and is located above the sealed chamber 2. The extended end of the normal jack 21 extends into the sealed chamber 2 through the first loading port. The extended end is equipped with a loading plate 17, and the loading plate 17 is equipped with a roller 18 for applying a normal loading force to the shear box 16. The fixed end of the tangential jack 23 is fixedly connected to the loading frame 1 and is located on the side of the sealed chamber 2. The extended end of the tangential jack 23 extends into the sealed chamber 2 through the second loading port to apply a tangential shear force to the upper box body.

[0034] The seepage system includes a seepage hydraulic pump 24, a fluid changer 25, a seepage fluid cylinder 26 and a waste fluid cylinder 32. The seepage fluid cylinder 26 is used to hold the fluid injected in the seepage test; the inlet of the fluid changer 25 is connected to the seepage fluid cylinder 26, so that the fluid in the seepage fluid cylinder 26 flows into the fluid changer 25, and the outlet of the fluid changer 25 is connected to the seepage inlet 14 of the shear box 16 through the seepage fluid conduit 27; the seepage hydraulic pump 24 is connected to the driving port of the fluid changer 25. When the seepage hydraulic pump 24 is started, it can drive the fluid in the fluid changer 25 to pass through the seepage inlet 14 at a certain pressure and be injected between the structural interfaces 37 for the seepage test; the drainage hole 19 is connected to the waste fluid cylinder 32 through a pipeline, and the waste liquid outlet 9 is connected to the waste liquid cylinder 32 through the waste liquid conduit 31. The waste liquid cylinder 32 is used to discharge the fluid passing through the structural interface 37 after the seepage test and the fluid in the sealing chamber 2 to the waste liquid cylinder 32 for recovery.

[0035] The load control and data acquisition system includes a load controller 30, a data acquisition device 33 and two load sensors 20. The two load sensors 20 are respectively installed on the protruding ends of the normal jack 21 and the tangential jack 23, and are used to monitor the normal loading force and tangential shear force applied by the normal jack 21 and the tangential jack 23 to the shear box 16, and feed back to the data acquisition device 33 for storage. The load controller 30 is respectively connected to the normal jack 21, the tangential jack 23 and the seepage hydraulic pump 24, and is used to control the pressure output by the normal jack 21 and the tangential jack 23, and the injection pressure output by the seepage hydraulic pump 24.

[0036] As an improvement of the present invention, a control valve 28 is installed on the pipeline between the seepage hydraulic pump 24 and the fluid changer 25 for controlling the on-off between the seepage hydraulic pump 24 and the fluid changer 25; a one-way valve 34 is installed on the pipeline between the seepage fluid cylinder 26 and the fluid changer 25, the seepage fluid conduit 27, the pipeline between the drainage hole 19 and the waste liquid cylinder 32, and the waste liquid conduit 31 for controlling the unidirectional flow of the fluid to prevent backflow from affecting the test.

[0037] As another improvement of the present invention, the side walls of the seepage fluid cartridge 26 and the waste liquid cartridge 32 are each provided with scales, so as to facilitate reading the amount of fluid in the seepage fluid cartridge 26 and the waste liquid cartridge 32 respectively.

[0038] The test method of the structural interface direct shear-seepage test device considering fluid viscosity has the following specific steps:

[0039] Step 1: Use rock to make a rectangular parallelepiped structure sample 35 with dimensions of 200 mm × 200 mm × 150 mm, and use mortar to make a rectangular parallelepiped bulk material sample 36 with dimensions of 200 mm × 200 mm × 150 mm. Both samples are saturated. Next, the seepage fluid is configured and its viscosity is determined. The pressures output by the normal jack 21 and the tangential jack 23, as well as the injection pressure output by the seepage hydraulic pump 24, are also set.

[0040] Step 2: Fix the lower sealed shell on the loading frame 1, and place the shear box 16 into the sealed chamber 2. Then place the structure sample 35 prepared in step 1 in the lower box body, and the bulk material sample 36 in the upper box body. Finally, fix the upper box body and the lower box body together to complete the installation of the shear box 16. Fix the two small sealed shells together to form the upper sealed shell. Finally, place the upper sealed shell on top of the lower sealed shell for fixed sealing.

[0041] Step 3: Assemble the direct shear loading system, seepage system, and the rest of the load control and data acquisition system in sequence;

[0042] Step 4: After assembly is completed, the waste liquid outlet 9 is blocked, and the fluid used for the seepage configured in step 1 is injected into the sealing chamber 2 through the fluid inlet 11, and the shear box 16 is ensured to be completely immersed in the fluid to achieve static sealing of the shear box 16;

[0043] Step 5: The load controller 30 controls the normal jack 21 to apply pressure, and monitors in real time through its load sensor 20 that the normal loading force it applies reaches a predetermined value and is maintained. Then, the load controller 30 controls the tangential jack 23 to apply shear stress, and monitors in real time through its load sensor 20 that the tangential shear force it applies reaches a predetermined value and is maintained. Then, the load controller 30 controls the seepage hydraulic pump 24 to start. The seepage hydraulic pump 24 injects the fluid in the commutator 25 into the shear box 16 at the set grouting pressure, and starts the direct shear-seepage test of the structural interface. During the test, the shear box 16 is completely immersed in the fluid, and the fluid in the sealing chamber 2 is exactly the same as the fluid injected by the seepage, thereby ensuring the sealing effect during the test.

[0044] Step 6: After the test is completed, the amount of fluid discharged from the drain hole 19 is obtained through the waste liquid cylinder 32, and the amount of fluid injected into the shear box 16 is obtained, and the data is stored in the data acquisition device 33. The viscosity of the fluid in this test, the pressure set by the normal jack 21 and the tangential jack 23, and the injection pressure output by the seepage hydraulic pump 24 are stored; finally, the waste liquid outlet 9 is opened to discharge the fluid in the sealed chamber 2, completing the entire test process;

[0045] Step 7: Prepare different structural samples 35, different bulk material samples 36, and fluids of different viscosities, and set different pressures output by the normal jack 21 and the tangential jack 23, as well as different injection pressures output by the seepage hydraulic pump 24; repeat steps 1 to 6 respectively, so as to obtain corresponding direct shear-seepage test data under different conditions.

[0046] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A structural interface direct shear-seepage test device considering fluid viscosity, comprising a direct shear loading system, a seepage system, and a load control and data acquisition system, characterized in that: The direct shear loading system also includes a sealed chamber, The sealing chamber includes a lower sealing shell and two small sealing shells, the two small sealing shells are fixedly connected to form an upper sealing shell, the upper sealing shell is located above the lower sealing shell, and the two are fixedly connected to form a sealing chamber; grooves are provided on the contact surfaces of the two small sealing shells and the contact surfaces of the upper sealing shell and the lower sealing shell, and sealing belts are installed in the grooves to seal each contact surface; the shear box of the direct shear loading system is placed in the sealing chamber, and a liquid injection hole, a fluid inlet, a first loading port, an exhaust hole and a wire hole are provided on the upper part of the sealing chamber, wherein the liquid injection hole is used for the liquid injection pipeline of the seepage system to be connected to the shear box through the liquid injection hole; the side of the sealing chamber is provided with a second loading port, a seepage outlet hole and a waste liquid outlet; The direct shear loading system includes a loading frame, a shear box, a normal jack and a tangential jack. The sealed chamber is fixed inside the loading frame by an integral fixing bolt. The shear box includes an upper box body and a lower box body. The shear box is made of a flexible material. The lower box body is fixed in the sealed chamber by a first positioning pin. The upper box body is located on the upper part of the lower box body and the two are fixedly connected by a second positioning pin. The structural sample is placed in the lower box body, and the bulk material sample is placed in the upper box body. A structural interface is formed between the structural sample and the bulk material sample. Infiltration holes and drainage holes are respectively provided on both sides of the shear box on the same horizontal plane. The fixed end of the normal jack is fixedly connected to the loading frame and is located above the sealed chamber. The protruding end of the normal jack extends into the sealed chamber through the first loading port; the protruding end is equipped with a loading plate, and the loading plate is equipped with a roller for applying a normal loading force to the shear box; the fixed end of the tangential jack is fixedly connected to the loading frame and is located on the side of the sealed chamber. The protruding end of the tangential jack extends into the sealed chamber through the second loading port, and is used to apply a tangential shear force to the upper box body; The seepage system includes a seepage hydraulic pump, a fluid changer, a seepage fluid cartridge and a waste fluid cartridge. The seepage fluid cartridge is used to hold the fluid injected in the seepage test. The inlet of the fluid changer is connected to the seepage fluid cartridge so that the fluid in the seepage fluid cartridge flows into the fluid changer. The outlet of the fluid changer is connected to the seepage inlet hole of the shear box through a seepage fluid conduit. The seepage hydraulic pump is connected to the drive port of the fluid changer. When the seepage hydraulic pump is started, it can drive the fluid in the fluid changer to pass through the seepage inlet hole at a certain pressure and be injected between the structural interfaces to perform the seepage test. The drainage hole is connected to the waste fluid cartridge through a pipeline. The waste liquid outlet is connected to the waste liquid cartridge through a waste liquid conduit. The waste liquid cartridge is used to discharge the fluid that passes through the structural interface after the seepage test and the fluid in the sealed chamber to the waste liquid cartridge for recovery.

2. The structural interface direct shear-seepage test device considering fluid viscosity according to claim 1, characterized in that: A control valve is installed on the pipeline between the seepage hydraulic pump and the fluid changer to control the on-off between the seepage hydraulic pump and the fluid changer; a one-way valve is installed on the pipeline between the seepage fluid cylinder and the fluid changer, the seepage fluid conduit, the pipeline between the drainage hole and the waste liquid cylinder, and the waste liquid conduit to control the one-way flow of the fluid.

3. The structural interface direct shear-seepage test device considering fluid viscosity according to claim 2, characterized in that: The side walls of the seepage liquid cylinder and the waste liquid cylinder are respectively provided with scales.

4. The structural interface direct shear-seepage test device considering fluid viscosity according to claim 1, characterized in that: The load control and data acquisition system includes a load controller, a data acquisition device and two load sensors. The two load sensors are respectively installed on the protruding ends of the normal jack and the tangential jack, and are used to monitor the normal loading force and tangential shear force applied by the normal jack and the tangential jack to the shear box, and feed back to the data acquisition device for storage. The load controller is respectively connected to the normal jack, the tangential jack and the seepage hydraulic pump, and is used to control the pressure output by the normal jack and the tangential jack, as well as the injection pressure output by the seepage hydraulic pump.

5. The structural interface direct shear-seepage test device considering fluid viscosity according to claim 1, characterized in that: The two small sealed shells are detachably fixedly connected via transverse fixing bolts; the upper sealed shell and the lower sealed shell are detachably fixedly connected via vertical fixing bolts.

6. A test method for a structural interface direct shear-seepage test device considering fluid viscosity according to any one of claims 1 to 5, characterized in that: The specific steps are: Step 1: Prepare a structure sample and a bulk material sample respectively, and saturate both samples. Then, prepare the fluid used for seepage, determine the viscosity of the fluid, and set the pressure output by the normal jack and tangential jack, as well as the injection pressure output by the seepage hydraulic pump; Step 2: Fix the lower sealed shell on the loading frame and place the shear box in the sealed chamber. Then place the structure sample prepared in step 1 in the lower box body and the bulk material sample in the upper box body. Finally, fix the upper box body and the lower box body together to complete the shear box installation. Fix the two small sealed shells together to form the upper sealed shell. Finally, place the upper sealed shell on top of the lower sealed shell for fixed sealing. Step 3: Assemble the direct shear loading system, seepage system, and the rest of the load control and data acquisition system in sequence; Step 4: After assembly is completed, the waste liquid outlet is blocked, and the fluid used for the seepage configured in step 1 is injected into the sealing chamber through the fluid inlet, and the shear box is ensured to be completely immersed in the fluid to achieve static sealing of the shear box; Step 5: The load controller controls the normal jack to apply pressure, and monitors the normal loading force applied by the load sensor in real time to reach the predetermined value and maintain it. Then, the load controller controls the tangential jack to apply shear stress, and monitors the tangential shear force applied by the load sensor in real time to reach the predetermined value and maintain it. Then, the load controller controls the start of the seepage hydraulic pump, and the seepage hydraulic pump injects the fluid in the commutator into the shear box at the set grouting pressure to start the structural interface direct shear-seepage test. During the test, the shear box is completely immersed in the fluid, and the fluid in the sealing chamber is exactly the same as the fluid injected by the seepage, thereby ensuring the sealing effect during the test. Step 6: After the test is completed, the amount of fluid discharged from the drain hole is obtained through the waste liquid cylinder, and the amount of fluid injected into the shear box is obtained. The data is stored in the data acquisition device, and the viscosity of the fluid in this test, the set pressure output by the normal jack and the tangential jack, and the injection pressure output by the seepage hydraulic pump are stored; finally, the waste liquid outlet is opened to discharge the fluid in the sealed chamber, completing the entire test process; Step 7. Prepare different structural samples, different bulk material samples, and fluids of different viscosities, and set different pressures output by the normal jack and tangential jack, as well as different injection pressures output by the seepage hydraulic pump; repeat steps 1 to 6 respectively, so as to obtain the corresponding direct shear-seepage test data under different conditions.

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