Device and method for simulating the effect of groundwater reciprocating flow on concrete crack propagation

Abstract

The application discloses a device and method for simulating influence of underground water reciprocating flow on concrete crack expansion, which comprises a sample box, a mud-water preparation system, a seepage driving system and a seepage flow control system. The sample box comprises a top plate, a bottom plate and two groups of enclosing plates. The two enclosing plates are symmetrically arranged between the top plate and the bottom plate, and a sample is placed between the two enclosing plates. Rubber pads are arranged between the enclosing plates and the outer wall of the sample. The top plate and the bottom plate are respectively fixedly connected with water pipes. The output end of the mud-water preparation system is fixedly connected with the water pipe on the bottom plate. The seepage driving system is fixedly connected with the water pipe on the top plate. The seepage flow control system comprises a flow control unit and a controller. A first fixing assembly is arranged between the top plate and the bottom plate, and a second fixing assembly is arranged between the two enclosing plates. The application can more accurately carry out research on the influence of underground water reciprocating scouring on crack expansion of brittle materials such as concrete, and can provide guidance for analysis of contents such as evolution process of tunnel bottom structure spewing and water disease.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rock mass engineering, in particular to a device and method for simulating the influence of reciprocating flow of underground water on concrete crack propagation. BACKGROUND

[0002] The bottom structure diseases such as spouting and water bursting are an important factor affecting the safety of tunnel service. The deterioration of the diseases cannot be separated from the expansion of seepage channels such as cracks. After the tunnel is built, with the increase of service time, underground water will gradually seep into the tunnel bottom to form a water-rich environment. Thereafter, the deformation of the tunnel bottom structure caused by train load will cause extrusion of water, so that underground water will flow in rock mass and concrete. When underground water flows in the crack, part of the soluble substances in the concrete (such as calcium hydroxide in the concrete, soil in the surrounding rock, etc.) will dissolve in the water and gradually migrate out of the crack with the flow of water. In addition, water flow erosion may also cause the material on the surface of the seepage channel to fall off and then migrate out of the crack with the flow of water. Both factors may cause the seepage channel to expand continuously, thereby causing the deterioration of the tunnel bottom structure diseases. Accurate understanding of the influence of water flow erosion under train load on crack evolution helps to evaluate the service state of the tunnel bottom structure, thereby improving the tunnel operation and maintenance level and reducing the operation risk.

[0003] At present, the research on the influence of water flow erosion on concrete (or rock) has made certain progress. For example, document 1 (Wu F, Shi K, Dong S, et al. Long-term seepage and dissolution stability test of plastic concrete [J]. Transactions of the Chinese Agricultural Engineering Society, 2014, 30(22): 112-119.) uses a constant water pressure mode to conduct a long-term seepage test; document 2 (Zhou Y, Mu S, Pu C, et al. Evaluation of tunnel primary support concrete anti-erosion and dissolution technology and its mechanism [J]. Materials Review, 2022, 36(4): 93-100.) uses a spraying method to study the calcium dissolution damage of tunnel primary support concrete. However, the research on the crack of concrete (or rock mass) under reciprocating erosion is still lacking, and there is a lack of related test devices and methods. Although there are test devices for the influence of reciprocating water flow on rock-soil mass (patent: asphalt mixture dynamic water erosion instrument, CN102706760A; high-frequency reciprocating direction-changing pavement material erosion device and using method thereof, CN115452639A), but they still cannot simulate the erosion of water flow reciprocating flow on concrete (or rock), and thus cannot effectively carry out the research on the influence of water flow reciprocating erosion on crack expansion, especially the research on the influence of mud-water mixture reciprocating erosion on crack expansion.

[0004] Based on the above technical problems, the present application provides a device and method for simulating the influence of reciprocating flow of underground water on concrete crack propagation. SUMMARY

[0005] The purpose of the present invention is to provide a device and method for simulating the influence of reciprocating groundwater flow on the expansion of concrete cracks, so as to solve the problems existing in the prior art.

[0006] To achieve the above object, the present invention provides the following solution: The present invention provides a device for simulating the effect of reciprocating groundwater flow on the expansion of concrete cracks, comprising:

[0007] A sample box is provided with several groups, comprising a top plate, a bottom plate, and two sets of enclosures, wherein the top plate and the bottom plate are arranged opposite each other, the cross-section of the enclosures is in the shape of a ⌚, the two enclosures are symmetrically arranged between the top plate and the bottom plate, a space is provided between the two enclosures, the sample is placed between the two enclosures, a rubber pad is provided between the enclosure and the outer wall of the sample, and the top plate and the bottom plate are respectively fixedly connected to a water pipe;

[0008] A muddy water preparation system, wherein the output end of the muddy water preparation system is fixedly connected to the water pipe on the bottom plate;

[0009] A seepage drive system, wherein the seepage drive system is fixedly connected to the water pipe on the top plate;

[0010] A seepage control system, comprising a flow control unit and a controller, wherein the controller is electrically connected to the flow control unit, and the flow control unit is respectively mounted on the water pipes of the top plate and the bottom plate;

[0011] Wherein, a first fixing component is provided between the top plate and the bottom plate, and a second fixing component is provided between the two enclosure plates.

[0012] According to the device for simulating the effect of reciprocating groundwater flow on the expansion of concrete cracks provided by the present invention, the mud water preparation system includes a water tank, a water inlet is opened at the top of the water tank, the water inlet is connected to an external water source, a stirring system is installed at the bottom of the water tank, a first circulation pipe is fixedly connected to the top of the water tank, one end of the first circulation pipe is connected to a diversion system, and a plurality of sample boxes are connected to the diversion system;

[0013] The diversion system includes a main pipeline, a plurality of diversion pipes are fixedly connected to the main pipeline, one end of the first circulation pipe is connected to the main pipeline, and the water pipes on the bottom plate are fixedly connected to the plurality of diversion pipes.

[0014] According to the device for simulating the effect of reciprocating groundwater flow on the expansion of concrete cracks provided by the present invention, the seepage drive system includes a cylinder body, a piston is slidably connected to the cylinder body, a second circulation pipe is fixedly connected to the top of the cylinder body, the second circulation pipe is connected to the water pipe on the top plate through the diversion system, and a connecting rod is fixedly connected to the bottom of the piston, and the connecting rod is connected to the drive system;

[0015] The drive system includes an active motor and a transmission, wherein the output shaft of the active motor is connected to the input shaft of the transmission, the output shaft of the transmission is fixedly connected to a crankshaft, one end of the connecting rod is fixedly connected to a connecting shaft, the connecting shaft is rotatably connected to the crankshaft, and the crankshaft and the connecting shaft are eccentrically matched;

[0016] Wherein, the second circulation pipe is connected to the main pipe of the diversion system, and the diversion pipe is communicated with the water pipe on the top plate.

[0017] According to the device for simulating the influence of the reciprocating flow of groundwater on the expansion of concrete cracks provided by the present invention, the flow control unit includes a plurality of valves and a plurality of flow meters, the plurality of flow meters are respectively arranged between the water pipe and the diversion pipe on the bottom plate, and the plurality of valves are respectively arranged between the water pipe and the diversion pipe on the top plate, and the valves and the flow meters are respectively connected to the controller.

[0018] According to the device for simulating the influence of the reciprocating flow of groundwater on the expansion of concrete cracks provided by the present invention, two groups of the second fixing components are provided, and the second fixing components include two groups of ribs and two groups of first screws. The two groups of ribs are respectively arranged on the outer walls of the two groups of enclosures away from each other, and abut against the enclosures. The two groups of first screws and the two groups of ribs are combined to form a rectangular structure, and the two ends of the first screw pass through the two groups of ribs respectively, and one end of the first screw is threadedly connected with a nut.

[0019] According to the device for simulating the influence of the reciprocating flow of groundwater on the expansion of concrete cracks provided by the present invention, the first fixing component includes four groups of second screws, and through holes are vertically opened on the four corners of the top plate. The four groups of second screws are respectively inserted into the through holes, and the bottom ends of the second screws pass through the bottom plate and are threadedly connected to the nuts.

[0020] According to the device for simulating the influence of the reciprocating flow of groundwater on the expansion of concrete cracks provided by the present invention, a positioning groove is provided on the outer wall of the enclosure, and the positioning groove is arranged along the width direction of the enclosure. The depth of the positioning groove is 1 mm and the width is 10 mm, and the rib plate is clamped in the positioning groove.

[0021] According to the device for simulating the effect of the reciprocating flow of groundwater on the expansion of concrete cracks provided by the present invention, square grooves are respectively opened on the top plate and the bottom plate, and the two enclosure plates are both clamped in the square grooves.

[0022] The method for simulating the effect of reciprocating groundwater flow on the propagation of concrete cracks includes the following steps:

[0023] Step 1: Select a specimen, record the initial crack data of the specimen, and place the specimen in a specimen box, ensuring that the cracks of the specimen are arranged vertically and correspond to the water pipes on the top and bottom plates, respectively. Place a rubber pad between the enclosure and the specimen, secure the top and bottom plates with a first fixing assembly, and secure the two sets of enclosures with a second fixing assembly.

[0024] Step 2: Connect the water pipe on the top plate to the seepage drive system, connect the water pipe on the bottom plate to the mud and water preparation system, and arrange the flow control unit between the water pipe on the top plate and the seepage drive system, and between the water pipe on the bottom plate and the mud and water preparation system respectively;

[0025] Step 3: The muddy water preparation system prepares muddy water of a preset concentration, the seepage drive system draws the muddy water from the muddy water preparation system into the sample box, and the flow control unit controls the flow rate;

[0026] Step 4: muddy water flows back and forth in the cracks of the specimen to simulate the effect of the reciprocating flow of groundwater on the cracks of the specimen;

[0027] Step 5: After the experiment, the sample box is opened and the sample is taken out. The crack data of the sample after the reciprocating flow of water is obtained and compared with the initial crack data. The two data are analyzed to complete the study on the impact of crack expansion.

[0028] The present invention discloses the following technical effects:

[0029] In the present invention, the mud water preparation system can prepare mud water of different concentrations according to different needs, and control the mud water to flush back and forth in the cracks of the sample through the seepage drive system, simulating the influence of the reciprocating flushing of groundwater on the cracks of the sample.

[0030] The test device and its use method proposed in the present invention can more accurately carry out research on the impact of reciprocating groundwater scouring on the expansion of cracks in brittle materials such as concrete (rock), and can provide guidance for the analysis of the evolution process of grouting and water seepage diseases in tunnel bottom structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 This is a schematic structural diagram of a device for simulating the effect of reciprocating groundwater flow on concrete crack expansion according to the present invention;

[0033] Figure 2 Schematic diagram of the structure of the sample box of the present invention;

[0034] Figure 3 2 is a cross-sectional view of the sample box of the present invention.

[0035] Among them, 1. Top plate; 2. Bottom plate; 3. Enclosure; 4. Rubber pad; 5. Water pipe; 6. Controller; 7. Water tank; 8. Water inlet; 9. Mixing system; 10. First circulation pipe; 11. Main pipeline; 12. Diversion pipe; 13. Cylinder body; 14. Piston; 15. Second circulation pipe; 16. Connecting rod; 17. Active motor; 18. Transmission; 19. Crankshaft; 20. Connecting shaft; 21. Valve; 22. Flowmeter; 23. Rib; 24. First screw; 25. Second screw. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Reference Figure 1-3 The present invention provides a device for simulating the effect of reciprocating groundwater flow on the expansion of concrete cracks, comprising:

[0039] The sample box is provided with several groups, including a top plate 1, a bottom plate 2 and two sets of enclosures 3. The top plate 1 and the bottom plate 2 are arranged opposite each other. The cross-section of the enclosure 3 is in the shape of a ⌚. The two enclosures 3 are symmetrically arranged between the top plate 1 and the bottom plate 2. A spacer is provided between the two enclosures 3. The sample is placed between the two enclosures 3. A rubber pad 4 is provided between the enclosure 3 and the outer wall of the sample. A water pipe 5 is fixedly connected to the top plate 1 and the bottom plate 2 respectively.

[0040] Muddy water preparation system, the output end of the muddy water preparation system is fixedly connected to the water pipe 5 on the bottom plate 2;

[0041] A seepage drive system, which is fixedly connected to the water pipe 5 on the top plate 1;

[0042] The seepage control system includes a flow control unit and a controller 6. The controller 6 is electrically connected to the flow control unit. The flow control unit is installed on the water pipes 5 of the top plate 1 and the bottom plate 2 respectively.

[0043] Among them, a first fixing component is provided between the top plate 1 and the bottom plate 2, and a second fixing component is provided between the two surrounding panels 3.

[0044] In the present invention, the mud water preparation system can prepare mud water of different concentrations according to different needs, and control the mud water to flush back and forth in the cracks of the sample through the seepage drive system, simulating the influence of the reciprocating flushing of groundwater on the cracks of the sample.

[0045] The test device and its use method proposed in the present invention can more accurately carry out research on the impact of reciprocating groundwater scouring on the expansion of cracks in brittle materials such as concrete (rock), and can provide guidance for the analysis of the evolution process of grouting and water seepage diseases in tunnel bottom structures.

[0046] Further optimization scheme, the muddy water preparation system includes a water tank 7, a water inlet 8 is opened on the top of the water tank 7, the water inlet 8 is connected to the external water source, a stirring system 9 is installed at the bottom of the water tank 7, and a first circulation pipe 10 is fixedly connected to the top of the water tank 7. One end of the first circulation pipe 10 is connected to the diversion system, and several sample boxes are connected to the diversion system;

[0047] The diversion system includes a main pipe 11 , to which a plurality of diversion pipes 12 are fixedly connected. One end of the first circulation pipe 10 is connected to the main pipe 11 , and the water pipes 5 on the bottom plate 2 are fixedly connected to the plurality of diversion pipes 12 .

[0048] Further optimized, the seepage drive system includes a cylinder 13, a piston 14 is slidably connected in the cylinder 13, a second circulation pipe 15 is fixedly connected to the top of the cylinder 13, the second circulation pipe 15 is connected to the water pipe 5 on the top plate 1 through the diversion system, and a connecting rod 16 is fixedly connected to the bottom of the piston 14, and the connecting rod 16 is connected to the drive system;

[0049] The drive system includes an active motor 17 and a transmission 18. The output shaft of the active motor 17 is connected to the input shaft of the transmission 18. The output shaft of the transmission 18 is fixedly connected to a crankshaft 19. One end of the connecting rod 16 is fixedly connected to a connecting shaft 20. The connecting shaft 20 is rotatably connected to the crankshaft 19, and the crankshaft 19 and the connecting shaft 20 are eccentrically matched.

[0050] The second circulation pipe 15 is connected to the main pipe 11 of the diversion system, and the diversion pipe 12 is communicated with the water pipe 5 on the top plate 1 .

[0051] The crankshaft 19 is driven to rotate by the active motor 17, and the crankshaft 19 rotates to pull the connecting rod 16, and the connecting rod 16 drives the piston 14 to move in the cylinder 13. The cylinder 13 is connected to the second circulation pipe 15. The second circulation pipe 15 is connected to the first circulation pipe 10 and the two-group diversion system to achieve reciprocating flow of muddy water in the cracks of the samples in the multiple groups of sample boxes, thereby conducting synchronous experiments on multiple groups of samples.

[0052] The stirring system 9 adopts existing technology, such as a stirring motor in combination with a stirring rod, or a paddle wheel in combination with a motor, and is specifically configured according to actual needs.

[0053] In a further optimized solution, the flow control unit includes a plurality of valves 21 and a plurality of flow meters 22. The plurality of flow meters 22 are respectively disposed between the water pipe 5 and the diversion pipe 12 on the bottom plate 2, and the plurality of valves 21 are respectively disposed between the water pipe 5 and the diversion pipe 12 on the top plate 1. The valves 21 and the flow meters 22 are respectively connected to a controller 6. The controller 6 adopts existing technology, and the specific model is selected according to actual needs and is not specifically limited in this embodiment.

[0054] A further optimized solution is provided with two groups of second fixing components, which include two groups of ribs 23 and two groups of first screws 24. The two groups of ribs 23 are respectively arranged on the outer walls of the two groups of enclosures 3 on the side away from each other, and abut against the enclosures 3. The two groups of first screws 24 and the two groups of ribs 23 are combined to form a rectangular structure, and the two ends of the first screw 24 pass through the two groups of ribs 23 respectively, and one end of the first screw 24 is threadedly connected with a nut.

[0055] A further optimized solution is that the first fixing assembly includes four groups of second screw rods 25, and vertical through holes are respectively opened on the four corners of the top plate 1. The four groups of second screw rods 25 are respectively inserted into the through holes, and the bottom ends of the second screw rods 25 pass through the bottom plate 2 and are threadedly connected with nuts.

[0056] To further optimize the solution, a positioning groove is provided on the outer wall of the enclosure 3. The positioning groove is arranged along the width direction of the enclosure 3. The depth of the positioning groove is 1 mm and the width is 10 mm. The rib 23 is clamped in the positioning groove.

[0057] To further optimize the solution, square grooves are respectively provided on the top plate 1 and the bottom plate 2, and the two surrounding panels 3 are both snapped into the square grooves.

[0058] The method for simulating the effect of reciprocating groundwater flow on the propagation of concrete cracks includes the following steps:

[0059] Step 1: Select a specimen, record the initial crack data of the specimen, and place the specimen in a specimen box, ensuring that the cracks of the specimen are arranged vertically and correspond to the water pipes 5 on the top plate 1 and bottom plate 2, respectively. Place a rubber pad 4 between the enclosure 3 and the specimen, secure the top plate 1 and bottom plate 2 with a first securing assembly, and secure the two sets of enclosures 3 with a second securing assembly.

[0060] Step 2: Connect the water pipe 5 on the top plate 1 to the seepage drive system, connect the water pipe 5 on the bottom plate 2 to the muddy water preparation system, and arrange the flow control unit between the water pipe 5 on the top plate 1 and the seepage drive system, and between the water pipe 5 on the bottom plate 2 and the muddy water preparation system respectively;

[0061] Step 3: The muddy water preparation system prepares muddy water of a preset concentration, the seepage drive system draws the muddy water from the muddy water preparation system into the sample box, and the flow control unit controls the flow rate;

[0062] Step 4: muddy water circulates in the cracks of the specimen to simulate the effect of groundwater circulation on the cracks of the specimen;

[0063] Step 5: After the experiment, the sample box is opened and the sample is taken out. The crack data of the sample after the reciprocating flow of water is obtained and compared with the initial crack data. The two data are analyzed to complete the study on the impact of crack expansion.

[0064] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0065] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A device for simulating the effect of reciprocating groundwater flow on the expansion of concrete cracks, characterized in that: Comprising: A sample box, with several groups of the sample boxes provided. The sample box includes a top plate (1), a bottom plate (2) and two sets of side plates (3). The top plate (1) and the bottom plate (2) are arranged opposite to each other. The cross-sectional shape of the side plate (3) is U-shaped. The two side plates (3) are symmetrically arranged between the top plate (1) and the bottom plate (2). There is a gap between the two side plates (3). The sample is placed between the two side plates (3). A rubber pad (4) is provided between the side plate (3) and the outer wall of the sample. Water pipes (5) are fixedly connected to the top plate (1) and the bottom plate (2) respectively; A muddy water preparation system, the output end of which is fixedly connected to the water pipe (5) on the bottom plate (2); A seepage driving system, which is fixedly connected to the water pipe (5) on the top plate (1); A seepage flow control system, which includes a flow control unit and a controller (6). The controller (6) is electrically connected to the flow control unit. The flow control unit is respectively installed on the water pipes (5) of the top plate (1) and the bottom plate (2); Wherein, a first fixing component is provided between the top plate (1) and the bottom plate (2), and a second fixing component is provided between the two side plates (3).

2. The device for simulating the effect of reciprocating groundwater flow on concrete crack expansion according to claim 1, characterized in that: The muddy water preparation system includes a water tank (7). An inlet (8) is opened at the top of the water tank (7), and the inlet (8) is connected to an external water source. A stirring system (9) is installed at the bottom of the water tank (7). The top end of the water tank (7) is fixedly connected to a first circulation pipe (10). One end of the first circulation pipe (10) is connected to a diversion system, and several sample boxes are all connected to the diversion system; The diversion system includes a main pipe (11). A number of diversion pipes (12) are fixedly connected to the main pipe (11). One end of the first circulation pipe (10) is connected to the main pipe (11), and the water pipes (5) on the bottom plate (2) are respectively fixedly connected and communicated with several diversion pipes (12).

3. The device for simulating the effect of reciprocating groundwater flow on concrete crack expansion according to claim 2, characterized in that: The seepage driving system includes a cylinder block (13). A piston (14) is slidably connected in the cylinder block (13). A second circulation pipe (15) is fixedly connected to the top of the cylinder block (13). The second circulation pipe (15) is communicated with the water pipe (5) on the top plate (1) through the diversion system. A connecting rod (16) is fixedly connected to the bottom of the piston (14), and the connecting rod (16) is connected to a driving system; The driving system includes a driving motor (17) and a transmission (18). The output shaft of the driving motor (17) is connected to the input shaft of the transmission (18). The output shaft of the transmission (18) is fixedly connected to a crankshaft (19). One end of the connecting rod (16) is fixedly connected to a connecting shaft (20). The connecting shaft (20) is rotatably connected to the crankshaft (19), and the crankshaft (19) and the connecting shaft (20) are eccentrically matched; The second circulation pipe (15) is connected to the main pipe (11) of the diversion system, and the diversion pipe (12) is connected to the water pipe (5) on the top plate (1).

4. The device for simulating the effect of reciprocating groundwater flow on concrete crack expansion according to claim 3, characterized in that: The flow control unit comprises a plurality of valves (21) and a plurality of flow meters (22). The plurality of flow meters (22) are respectively arranged between the water pipe (5) and the diversion pipe (12) on the bottom plate (2). The plurality of valves (21) are respectively arranged between the water pipe (5) and the diversion pipe (12) on the top plate (1). The valves (21) and the flow meters (22) are respectively connected to the controller (6).

5. The device for simulating the effect of reciprocating groundwater flow on concrete crack expansion according to claim 1, characterized in that: The second fixing assembly is provided with two groups, and the second fixing assembly includes two groups of ribs (23) and two groups of first screws (24). The two groups of ribs (23) are respectively provided on the outer walls of the two groups of enclosures (3) away from each other, and are in contact with the enclosures (3). The two groups of first screws (24) and the two groups of ribs (23) are combined to form a rectangular structure, and the two ends of the first screw (24) pass through the two groups of ribs (23) respectively, and one end of the first screw (24) is threadedly connected with a nut.

6. The device for simulating the effect of reciprocating groundwater flow on concrete crack expansion according to claim 5, characterized in that: The first fixing assembly comprises four groups of second screw rods (25), four corners of the top plate (1) are respectively provided with vertical through holes, the four groups of second screw rods (25) are respectively inserted into the through holes, and the bottom ends of the second screw rods (25) pass through the bottom plate (2) and are threadedly connected to the nuts.

7. The device for simulating the effect of reciprocating groundwater flow on concrete crack expansion according to claim 5, characterized in that: The outer wall of the enclosure (3) is provided with a positioning slot, which is arranged along the width direction of the enclosure (3), has a depth of 1 mm and a width of 10 mm, and the rib (23) is clamped in the positioning slot.

8. The device for simulating the effect of reciprocating groundwater flow on concrete crack expansion according to claim 1, characterized in that: The top plate (1) and the bottom plate (2) are respectively provided with square grooves, and the two enclosure plates (3) are both clamped in the square grooves.

9. A method for simulating the effect of reciprocating groundwater flow on the expansion of concrete cracks, based on the device for simulating the effect of reciprocating groundwater flow on the expansion of concrete cracks according to any one of claims 1 to 8, characterized in that: The steps include: Step 1: Select a sample, record the data of the sample cracks in the initial state, arrange the sample in a sample box, ensure that the cracks of the sample are arranged vertically and correspond to the water pipes (5) on the top plate (1) and the bottom plate (2), respectively, arrange a rubber pad (4) between the enclosure (3) and the sample, use a first fixing assembly to fix the top plate (1) and the bottom plate (2), and use a second fixing assembly to fix the two sets of enclosures (3); Step 2: Connect the water pipe (5) on the top plate (1) to the seepage drive system, connect the water pipe (5) on the bottom plate (2) to the mud and water preparation system, and arrange the flow control unit between the water pipe (5) on the top plate (1) and the seepage drive system, and between the water pipe (5) on the bottom plate (2) and the mud and water preparation system; Step 3: The muddy water preparation system prepares muddy water of a preset concentration, the seepage drive system draws the muddy water from the muddy water preparation system into the sample box, and the flow control unit controls the flow rate; Step 4: muddy water flows back and forth in the cracks of the specimen to simulate the effect of the reciprocating flow of groundwater on the cracks of the specimen; Step 5: After the experiment, the sample box is opened and the sample is taken out. The crack data of the sample after the reciprocating flow of water is obtained and compared with the initial crack data. The two data are analyzed to complete the study on the impact of crack expansion.

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