High water pressure trapdoor model test device and use method

Abstract

The application provides a high water pressure Trapdoor model test device and a use method thereof. The high water pressure Trapdoor model test device comprises a PIV analysis unit, liquid material, solid material, a pore water pressure gauge, a first soil pressure sensor, a second soil pressure sensor, a third soil pressure sensor, a test box, and a pressure charging unit. The test box body is provided with an opening, and the opening is closed by a base plate. The base plate is provided with an opening, and the opening is provided with a movable door. The movable door can move up and down. The third soil pressure sensor is arranged in the movable door. The first soil pressure sensor is arranged in the base plate. The base plate is filled with the solid material. The second soil pressure sensor and the pore water pressure gauge are arranged in the solid material. The solid material is filled with the liquid material. A space for filling gas is reserved between the liquid material and the inner wall of the top cover of the test box body. The application has the beneficial effect that the formation and evolution mechanism of soil arch under high water pressure can be explored.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering technology, and in particular to a high water pressure Trapdoor model test device and its usage method. Background Technology

[0002] Soil arching is a common phenomenon in geotechnical engineering. To date, numerous scholars both domestically and internationally have conducted extensive research on model tests. However, existing studies have primarily focused on single-phase research with solid materials in a dry state, with a lack of research considering two-phase soil arching effects involving liquids. Furthermore, existing experimental models do not consider material pretreatment, resulting in low utilization of material properties.

[0003] Chinese Patent Application No. 202011376084.0 discloses a "Trapdoor model test device and test method under static and dynamic load conditions," including a test box for containing backfill, a loading mechanism, a fixing unit, and a Trapdoor module. The Trapdoor module consists of a thin plate and a spring located at the bottom of the thin plate. This device considers the relationship between the displacement of the movable door and the pressure of the overlying soil, but this patent cannot study the development law of the soil arching effect in the presence of liquid. Chinese Patent Application No. 201710306490.1 discloses a "dynamic soil arching model test system and method based on transparent soil technology." This test system can observe the evolution of the soil arch in real time, but the pressure conditions it can consider are limited, and it cannot conduct research under high pressure conditions. The devices described in Chinese Patent Application Nos. 202020357272.8 and 202010193579.3 can test the soil arching effect generated by spaces of different widths of overlapping tunnels; however, the materials used in the test devices are not pretreated, and the pressure levels that can be studied under the same conditions are relatively low. Chinese patent applications 202020208108.0 and 202010117689.1 employ adjustable water and soil pressurization devices, which can effectively study the seepage and erosion patterns of tunnels at different locations in water-rich sandy soil strata with different water heads. However, they cannot guarantee that the pressure inside the test chamber remains constant. Chinese patent application 201911252029.8 discloses "An experimental device for simulating the dynamic soil arching effect of a scaffold structure," which addresses the limited research on the dynamic soil arching effect of scaffold structures. However, this device does not consider the sealing problem of liquid presence, making it difficult to explore the evolution law of soil arching under two-phase conditions. Summary of the Invention

[0004] This invention provides a high water pressure Trapdoor model test device, including a PIV analysis unit, a liquid material, a solid material, a pore water pressure gauge, a soil pressure sensor, a test chamber, and a pressurization unit. The soil pressure sensor includes a first soil pressure sensor, a second soil pressure sensor, and a third soil pressure sensor. The test chamber has an opening, which is sealed by a base plate. The base plate has a hole, and a movable door is located at the hole. The movable door can move up and down. The third soil pressure sensor is arranged inside the movable door. The first soil pressure sensor is arranged inside the base plate. The base plate is filled with the solid material. The second soil pressure sensor and the pore water pressure gauge are arranged inside the solid material. The liquid material is filled on the solid material. A predetermined space is reserved between the liquid material and the inner wall of the test chamber's top cover for filling with gas. The pressurization unit is connected to the test chamber and is used to fill the test chamber with gas. The PIV analysis unit is used to record the development and deepening pattern of soil arching within the test chamber.

[0005] As a further improvement of the present invention, the substrate includes a first pad, a support column and a base, the support column is installed below the first pad and the support column is mounted on the base, and the first soil pressure sensor is arranged inside the first pad.

[0006] As a further improvement of the present invention, the movable door includes a Trapdoor module and a driving device, the driving device driving the Trapdoor module to move up and down; the Trapdoor module includes a second pad, a telescopic column, and a support, the second pad is installed on the support through the telescopic column, and the third earth pressure sensor is arranged inside the second pad.

[0007] As a further improvement of the present invention, there are multiple first pads and multiple pillars, with two pillars installed under each first pad; there are multiple second pads, with one or more second pads installed on each retractable pillar; and there are one or more Trapdoor modules.

[0008] As a further improvement of the present invention, the number of pore water pressure gauges is multiple, and the solid material is filled into the test chamber in a layered filling manner. Each layer of the solid material is provided with the second soil pressure sensor and the pore water pressure gauge at a set interval along the horizontal and vertical directions of the high water pressure Trapdoor model test device.

[0009] As a further improvement of the present invention, the top cover, left side wall, right side wall and rear panel of the test chamber are configured as outwardly protruding bulges, and an observation window is provided on the test chamber body, which is located on the front panel of the test chamber body.

[0010] As a further improvement of the present invention, the top cover, left side wall, right side wall, and rear panel of the test chamber are respectively configured as one or more outwardly protruding bulge shapes; the multiple bulges on the top cover of the test chamber form a wave shape; the top cover, left side wall, right side wall, and rear panel of the test chamber are made of steel plate or aluminum plate; the observation window is made of flat plate, and the flat plate is made of transparent plexiglass.

[0011] As a further improvement of the present invention, the solid material includes sand, soil, gravel, and glass beads, and the liquid material includes water, glycerol, and mud; the PIV analysis unit includes an imaging device and a PIV analysis system, the PIV analysis system being used to record the development and deepening law of soil arching within the test chamber; the high water pressure Trapdoor model test device also includes a vent pipe and a sealing ring, the test chamber body is provided with a through hole, one end of the vent pipe passes through the through hole into the test chamber body, the other end of the vent pipe is connected to the pressurization unit, and the sealing ring is installed between the outer surface of the vent pipe and the through hole; the high water pressure Trapdoor model test device also includes a data collection system, the data collection system being used to record data from the soil pressure sensor and the pore water pressure gauge.

[0012] As a further improvement of the present invention, the pressurization unit includes an air compressor, a pressure gauge, and a data adjustment system. The data adjustment system is connected to the air compressor and the pressure gauge, respectively. The air compressor is connected to the pressure gauge, and the pressure gauge is connected to the vent pipe.

[0013] This invention also discloses a method for using a high-water-pressure Trapdoor model testing device, comprising the following steps:

[0014] Step 1: Prepare the liquid material according to the particle size distribution curve of the solid material required for the experiment, and add the liquid material with the required concentration and composition according to the experimental requirements.

[0015] Step 2: Determine the number and direction of movement of the movable doors, and ensure that the height of the Trapdoor module is consistent with that of the substrate before filling the test material.

[0016] Step 3: Arrange a third earth pressure sensor in the second pad of the Trapdoor module and a first earth pressure sensor in the first pad of the substrate. Add solid material into the test chamber in a layered filling manner. Arrange a second earth pressure sensor and a pore water pressure gauge at a set interval for each layer of solid material.

[0017] Step 4: Read the data from the soil pressure sensor and pore water pressure gauge. After the data stabilizes, record the data. Then, add liquid material into the test chamber until it reaches the specified height, and let it stand until the data reading stabilizes again.

[0018] Step 5: According to the pressure conditions described in the test, fill the test chamber with gas. When the pressure gauge reading reaches the specified value, let it stand for a period of time. During this period, the air compressor should always be on until the test is over.

[0019] Step 6: First, turn on the PIV analysis unit, then turn on the Trapdoor module, causing the Trapdoor module to rise / fall. The PIV analysis unit is responsible for recording the development and evolution of the soil arch within the test chamber, while the data collection system is responsible for recording the data from the soil pressure sensor and pore water pressure gauge.

[0020] In step 3, each layer of the solid material is provided with the second soil pressure sensor and the pore water pressure gauge at set intervals along the horizontal and vertical directions of the high water pressure Trapdoor model test device.

[0021] In step 5, the air pressure inside the test chamber is servo-regulated and controlled by the data adjustment system to ensure that the pressure inside the test chamber remains constant.

[0022] The beneficial effects of this invention are: 1. The high water pressure Trapdoor model test device of this invention can explore the formation and evolution mechanism of soil arches under high water pressure conditions; 2. The high water pressure Trapdoor model test device of this invention can add different liquid materials according to the needs of experimental research; 3. The high water pressure Trapdoor model test device of this invention considers the pretreatment of outward bulges and wavy shapes of the model device material, so as to maximize the utilization of material strength. Attached Figure Description

[0023] Figure 1 This is a cross-sectional view of the high water pressure Trapdoor model test device of the present invention;

[0024] Figure 2 This is a cross-sectional view of the side of the high water pressure Trapdoor model test device of the present invention;

[0025] Figure 3 This is a structural diagram of the wave-shaped top cover of the high water pressure Trapdoor model test device of the present invention;

[0026] Figure 4 This is a structural diagram showing that the right side wall of the high water pressure Trapdoor model test device of the present invention is in the shape of a bulge;

[0027] Figure 5 This is a structural diagram of the right side wall of the high water pressure Trapdoor model test device of the present invention, which has multiple bulge shapes.

[0028] Figure 6 This is a structural diagram of a single Trapdoor module of the high water pressure Trapdoor model test device of the present invention;

[0029] Figure 7 This is a structural diagram of the multi-Trapdoor module of the high water pressure Trapdoor model test device of the present invention;

[0030] Figure 8 This is a structural diagram of a second pad block installed on the Trapdoor module of the present invention;

[0031] Figure 9 This is a structural diagram of two second pad blocks installed on the Trapdoor module of the present invention. Detailed Implementation

[0032] like Figure 1-2 As shown, this invention discloses a high water pressure Trapdoor model test device, including a PIV analysis unit 1, a liquid material 8, a solid material 9, a pore water pressure gauge 10, a first earth pressure sensor 11, a second earth pressure sensor, a third earth pressure sensor 24, a test chamber 19, and a pressurization unit. The test chamber 19 has an opening, which is sealed by a base plate. The base plate has an opening with a movable door that can move up and down. The third earth pressure sensor 24 is arranged inside the movable door, and the first earth pressure sensor is arranged inside the base plate. 11. The substrate is filled with the solid material 9, and the second soil pressure sensor and the pore water pressure gauge 10 are arranged inside the solid material 9. The solid material 9 is filled with the liquid material 8, and a predetermined space is reserved between the liquid material 8 and the inner wall of the top cover of the test chamber 19 for filling with gas 16. The pressurization unit is connected to the test chamber 19 and is used to fill the test chamber 19 with gas 16. The PIV analysis unit 1 is used to record the development and deepening law of soil arching in the test chamber 19. The test chamber 19 is also provided with an observation window.

[0033] The test chamber 19 has a top cover 17, left side wall 26, right side wall 7, and rear panel 28 that are shaped like outward bulges. The top cover 17 and side wall 7 of the test chamber 19 can be made of materials such as steel plate or aluminum plate. The observation window at the front of the test chamber 19 is a transparent glass, which is horizontal.

[0034] like Figure 3-5As shown, the top cover 17 and the two outwardly protruding bulges on the two side walls of the test chamber 19 can be a single bulge or a combination of multiple bulges; the multiple bulges on the top cover 17 of the test chamber 19 form a wave shape.

[0035] The solid material 9 is filled in the test chamber 19 in a layered manner; after the solid material 9 is filled, a certain height of liquid material 8 is added into the test chamber 19, and a certain space is reserved for filling gas 16.

[0036] Inside the solid material 9, a second earth pressure sensor and a pore water pressure gauge 10 are arranged at certain intervals along the horizontal and vertical directions of the high water pressure Trapdoor model test device; the solid material 9 can be materials such as sand, soil, gravel, and glass beads; the liquid material 8 can be water, glycerin, mud, etc.

[0037] The PIV analysis unit 1 includes an imaging device and a PIV analysis system, which is used to record the development and deepening of soil arching in the test chamber 19; the high water pressure Trapdoor model test device also includes a data collection system, which is used to record data from the soil pressure sensor and the pore water pressure gauge 10.

[0038] like Figure 6-9 As shown, the Trapdoor module 15 consists of a second pad 21, a telescopic column 22, and a support 23; the Trapdoor module 15 can move one or more second pads 21; the number of Trapdoor modules 15 can be one or more.

[0039] The movement of the Trapdoor module 15 is controlled by a drive device, which is preferably a servo control system; the Trapdoor module 15 can move upward or downward.

[0040] The base plate consists of a first pad 12, a support column 13 and a base 14; the first soil pressure sensor 11 is embedded in the first pad 12.

[0041] The pressurization unit consists of an air compressor 2, a pressure gauge 3, and a data adjustment system 4; the air compressor 2 is connected to the pressure gauge 3 through a vent pipe 5 and is connected to the test chamber 19.

[0042] The vent pipe 5 passes through the pre-drilled hole in the left side wall 26 and enters the chamber of the test chamber 19; the space between the vent pipe 5 and the hole in the left side wall 26 is filled with a sealing ring 6.

[0043] During the pressurization process, the pressurization unit uses the data obtained from the pressure gauge 3 to adjust the system 4 to servo control the pressure inside the test chamber 19 to maintain a constant value.

[0044] This invention also discloses a method for using a high-water-pressure Trapdoor model testing device, comprising the following steps:

[0045] Step 1: Prepare the solid material 9 according to the particle size distribution curve required for the experiment, and add the liquid material 8 with the appropriate concentration and composition according to the experimental requirements.

[0046] Step 2: Determine the number and displacement direction of the movable doors, and ensure that the height of the Trapdoor module 15 is consistent with that of the substrate before filling the test material.

[0047] Step 3: Arrange a third earth pressure sensor 24 in the second pad 21 of the Trapdoor module 15, arrange a first earth pressure sensor 11 in the first pad 12 of the base plate, add solid material 9 to the test chamber 19 in a layered filling manner, and arrange a second earth pressure sensor and a pore water pressure gauge 10 in each layer of solid material 9 at a set interval along the horizontal and vertical directions of the high water pressure Trapdoor model test device, respectively.

[0048] Step 4: Read the data from the soil pressure sensor and pore water pressure gauge 10. After the data stabilizes, record the data. Then add liquid material 8 into the test chamber 19. When adding liquid material 8, be careful not to affect the surface contour of the solid material. After reaching the specified height, let it stand until the data reading stabilizes again. Record the data. Do not fill the entire test chamber 19 with liquid material.

[0049] Step 5: According to the pressure conditions described in the test, gas is filled into the test chamber 19. When the reading of pressure gauge 3 reaches the specified value, it is left to stand for a period of time. During this period, air compressor 2 is always turned on until the test ends.

[0050] Step 6: First, turn on the PIV analysis unit 1, then turn on the Trapdoor module 15, causing the Trapdoor module 15 to rise / fall. The PIV analysis unit 1 is responsible for recording the development and evolution of the soil arch inside the test chamber 19, and the data collection system is responsible for recording the data from the soil pressure sensor and the pore water pressure gauge 10.

[0051] The beneficial effects of this invention are as follows: 1. The high water pressure Trapdoor model test device of this invention can explore the formation and evolution mechanism of soil arches under high water pressure conditions; 2. The high water pressure Trapdoor model test device of this invention can add different liquid materials according to the needs of experimental research; 3. The high water pressure Trapdoor model test device of this invention takes into account the pretreatment of outward bulges and wavy shapes of the model device material, so as to maximize the utilization of material strength.

[0052] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A high-water-pressure Trapdoor model test device, characterized in that: The system includes a PIV analysis unit (1), a liquid material (8), a solid material (9), a pore water pressure gauge (10), a soil pressure sensor, a test chamber (19), and a pressurization unit. The soil pressure sensor includes a first soil pressure sensor (11), a second soil pressure sensor, and a third soil pressure sensor (24). The test chamber (19) has an opening, which is sealed by a base plate. The base plate has a hole, and the hole has a movable door that can move up and down. The third soil pressure sensor (24) is arranged inside the movable door, and the first soil pressure sensor (11) is arranged inside the base plate. The substrate is filled with the solid material (9), the second soil pressure sensor and the pore water pressure gauge (10) are arranged in the solid material (9), the solid material (9) is filled with the liquid material (8), a set space is reserved between the liquid material (8) and the inner wall of the top cover (17) of the test chamber (19) for filling gas (16), the pressurization unit is connected to the test chamber (19), the pressurization unit is used to fill the test chamber (19) with gas (16), and the PIV analysis unit (1) is used to record the development and deepening law of soil arching in the test chamber (19); The top cover (17), left side wall (26), right side wall (7), and rear panel (28) of the test chamber (19) are set in an outward bulging shape. The test chamber (19) is provided with an observation window, which is located on the front panel of the test chamber (19).

2. The high water pressure Trapdoor model test apparatus according to claim 1, characterized in that: The substrate includes a first pad (12), a support column (13) and a base (14). The support column (13) is installed below the first pad (12) and the support column (13) is installed on the base (14). The first soil pressure sensor (11) is arranged inside the first pad (12).

3. The high water pressure Trapdoor model test apparatus according to claim 2, characterized in that: The movable door includes a Trapdoor module (15) and a drive device. The drive device drives the Trapdoor module (15) to move up and down. The Trapdoor module (15) includes a second pad (21), a telescopic column (22), and a support (23). The second pad (21) is installed on the support (23) through the telescopic column (22). The third earth pressure sensor (24) is arranged inside the second pad (21).

4. The high water pressure Trapdoor model test apparatus according to claim 3, characterized in that: The number of the first pad (12) and the number of the support pillars (13) are multiple, and two support pillars (13) are installed under each first pad (12); the number of the second pads (21) is multiple, and one or more second pads (21) are installed on the telescopic pillars (22); the number of the Trapdoor modules (15) is one or more.

5. The high water pressure Trapdoor model test apparatus according to claim 1, characterized in that: The number of pore water pressure gauges (10) is multiple. The solid material (9) is filled into the test chamber (19) in a layered filling manner. Each layer of the solid material (9) is arranged with the second soil pressure sensor and the pore water pressure gauge (10) at a set interval along the horizontal and vertical directions of the high water pressure Trapdoor model test device.

6. The high water pressure Trapdoor model test apparatus according to claim 1, characterized in that: The top cover (17), left side wall (26), right side wall (7), and rear panel (28) of the test chamber (19) are respectively set as one or more outward protruding bulge shapes; the multiple bulges on the top cover (17) of the test chamber (19) form a wave shape; the top cover (17), left side wall (26), right side wall (7), and rear panel (28) of the test chamber (19) are made of steel plate or aluminum plate; the observation window is made of flat plate, and the flat plate is made of transparent organic glass.

7. The high water pressure Trapdoor model test apparatus according to claim 1, characterized in that: The solid material (9) includes sand, soil, gravel and glass beads, and the liquid material (8) includes water, glycerol and mud. The PIV analysis unit includes a camera and a PIV analysis system. The PIV analysis system is used to record the development and deepening of soil arching in the test chamber (19). The high water pressure Trapdoor model test device also includes a vent pipe (5) and a sealing ring (6). The test chamber (19) has a through hole. One end of the vent pipe (5) passes through the through hole and enters the test chamber (19). The other end of the vent pipe (5) is connected to the pressurization unit. The sealing ring (6) is installed between the vent pipe (5) and the through hole. The high water pressure Trapdoor model test device also includes a data collection system. The data collection system is used to record the data on the soil pressure sensor and the pore water pressure gauge (10).

8. The high water pressure Trapdoor model test apparatus according to claim 7, characterized in that: The pressurization unit includes an air compressor (2), a pressure gauge (3), and a data adjustment system (4). The data adjustment system (4) is connected to the air compressor (2) and the pressure gauge (3) respectively. The air compressor (2) is connected to the pressure gauge (3), and the pressure gauge (3) is connected to the vent pipe (5).

9. A method of using the high water pressure Trapdoor model test apparatus as described in claim 1, characterized in that, This includes performing the following steps: Step 1: Prepare the solid material (9) according to the particle size distribution curve required for the experiment, and add the liquid material (8) with the corresponding concentration and composition according to the experimental requirements. Step 2: Determine the number and displacement direction of the movable doors, and ensure that the height of the Trapdoor module (15) is consistent with that of the substrate before filling the test material; Step 3: Arrange a third earth pressure sensor (24) in the second pad (21) of the Trapdoor module (15), arrange a first earth pressure sensor (11) in the first pad (12) of the substrate, add solid material (9) into the test chamber (19) in a layered filling manner, and arrange a second earth pressure sensor and a pore water pressure gauge (10) in the solid material (9) at a set interval. Step 4: Read the data from the soil pressure sensor and pore water pressure gauge (10), wait for the data to stabilize, record the data at this time, and then add liquid material (8) into the test chamber (19) until it reaches the specified height, and let it stand until the data reading stabilizes again; Step 5: According to the pressure conditions required for the test, gas is filled into the test chamber (19). When the reading of the pressure gauge (3) reaches the specified value, it is left to stand for a period of time. During this period, the air compressor (2) is always on until the test ends. Step 6: First turn on the PIV analysis unit (1), then turn on the Trapdoor module (15) so that the Trapdoor module (15) rises / falls. The PIV analysis unit (1) is responsible for recording the development and evolution of the soil arch in the test chamber (19), and the data collection system is responsible for recording the data on the soil pressure sensor and the pore water pressure gauge (10). In step 3, each layer of the solid material (9) is provided with the second soil pressure sensor and the pore water pressure gauge (10) at a set interval along the horizontal and vertical directions of the high water pressure Trapdoor model test device. In step 5, the air pressure inside the test chamber (19) is servo-regulated and controlled by the data regulation system (4) to ensure that the pressure inside the test chamber (19) remains constant.

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