Underground pipeline leakage test device and use method thereof

Abstract

The present invention relates to the technical field of geotechnical testing, and in particular to an underground pipeline leakage testing device and a method for using the same. The underground pipeline leakage testing device comprises a water collecting box, a water pipe with a leakage hole on the side wall, a transparent box body with transparent soil, and a particle image velocimetry system for photographing the transparent box body; the water collecting box is provided with an overflow chamber, the middle part of the water pipe is sealed and penetrated in the lower part of the transparent box body, the left end of the water pipe is connected to a water supply device for filling water in the box water pipe, the right end of the water pipe is connected to the bottom of the overflow chamber, the depth of the overflow chamber is adjustable, the leakage hole is located in the transparent box body, a sealing plug is provided in the leakage hole, one end of the sealing plug located in the water pipe is connected to a pulling rope, the other end of the pulling rope penetrates into the overflow chamber from the right end of the water pipe, and the sealing plug can be pulled out of the water pipe from the right end of the water pipe by pulling the pulling rope, thereby preventing the soil outside the water pipe from leaking into the water pipe before the water flow is stable, thereby ensuring the test accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical testing, and in particular to an underground pipeline leakage testing device and a use method thereof. Background Art

[0002] With the accelerated development of urbanization in my country, the construction of urban underground pipelines, roads and urban tunnels is in full swing, which has brought about a series of disasters such as urban ground collapse. Urban ground collapse is very harmful and seriously affects the personal and property safety of urban residents. According to the statistical analysis of ground collapse accidents, 55% of ground collapse accidents are caused by damage and leakage of urban water supply pipelines. Therefore, it is necessary to carry out relevant indoor test research to fundamentally solve the problem of ground collapse caused by underground pipeline leakage.

[0003] The difference in water pressure has a great influence on the deformation of the soil layer outside the pipe with leaking holes. The Chinese invention patent with publication number CN115372237A discloses an experimental method and device for observing seepage erosion based on transparent soil. It realizes three-dimensional observation of the permeability of transparent soil through particle image velocimetry technology; transparent soil test technology is used to study the deformation diagram, displacement field, and velocity field at any position in the soil during the seepage process, truly simulate the seepage process and accurately monitor the changes in the seepage field, which can be applied to the prevention and control of seepage erosion. However, its water inlet is set at the upper end of the seepage cavity, and the water outlet is set at the lower end of the seepage cavity, which cannot simulate the actual situation of the local existence of leaking holes in the underground pipeline under the soil. Therefore, there is an urgent need for an underground pipeline leakage test device that can simulate underground pipeline leakage and adjust the water pressure. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide an underground pipeline leakage test device, comprising a water collecting tank, a water pipe with a leakage hole on the side wall, a transparent box body with transparent soil and a particle image velocimetry system for photographing the transparent box body; the water collecting tank is provided with an overflow chamber, the middle part of the water pipe is sealed and penetrated through the lower part of the transparent box body, the left end of the water pipe is connected to a water supply device for filling water into the water pipe, the right end of the water pipe is connected to the bottom of the overflow chamber, the depth of the overflow chamber is adjustable to change the water pressure at the right end of the water pipe, the leakage hole is located in the transparent box body, a sealing plug is provided in the leakage hole, one end of the sealing plug located in the water pipe is connected to a pulling rope, the other end of the pulling rope penetrates into the overflow chamber from the right end of the water pipe, and the sealing plug can be pulled out of the water pipe from the right end of the water pipe by pulling the pulling rope.

[0005] As a preferred embodiment, the water collecting tank includes a water collecting tank body, a partition is sealed and inserted in the middle of the water collecting tank body, the partition divides the inner cavity of the water collecting tank body into a first cavity and a second cavity, the first cavity forms the overflow cavity, and the partition can be extended and retracted up and down to adjust the depth of the overflow cavity.

[0006] As a preferred solution, the bottom of the second cavity is communicated with the water inlet end of the water supply device.

[0007] As a preferred solution, a plurality of pore water pressure gauges are arranged at intervals up and down on the inner side wall of the transparent box.

[0008] As a preferred embodiment, the water supply device includes a variable frequency water pump and a water tank, the inlet end of the variable frequency water pump is connected to the water tank, the outlet end of the variable frequency water pump is connected to the left end of the water pipe, and a first flow meter for measuring the water flow velocity at the upstream position of the leakage hole is provided between the variable frequency water pump and the leakage hole.

[0009] As a preferred solution, the water pipe is provided with a second flow meter for measuring the water flow velocity at a position downstream of the water leakage hole at a position between the water leakage hole and the right end of the water pipe.

[0010] As a preferred embodiment, the particle image velocimetry system includes a laser emitter, a first camera and a second camera, wherein the laser emitter is located on the left side of the transparent box, the first camera is located on the right side of the transparent box, and the second camera is located in front of the transparent box.

[0011] As a preferred solution, the water pipe is a plexiglass pipe.

[0012] A method for using the above-mentioned underground pipeline leakage test device comprises the following steps:

[0013] Step S1, adding transparent soil with a specific particle size distribution into a transparent box;

[0014] Step S2, turning on the water supply device so that water flows into the overflow chamber through the water pipe until the overflow chamber is filled with water and overflows stably;

[0015] Step S3, pulling the pulling rope to pull the sealing plug out of the leaking hole, and photographing it through the particle image velocimetry system;

[0016] Step S4, adjusting the depth of the overflow cavity, and repeating steps S1 to S3.

[0017] As a preferred solution, in step S3, the sealing plug is pulled out from the water leakage hole after the values ​​of the first flow meter and the second flow meter are stabilized.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The underground pipeline leakage test device of the present invention comprises a water collecting box, a water pipe with a leakage hole on the side wall, a transparent box body with transparent soil, and a particle image velocimetry system for photographing the transparent box body; the water collecting box is provided with an overflow cavity, the middle part of the water pipe is sealed and penetrated in the lower part of the transparent box body, the left end of the water pipe is connected with a water supply device for filling water in the box water pipe, the right end of the water pipe is connected with the bottom of the overflow cavity, the depth of the overflow cavity is adjustable to change the water pressure at the right end of the water pipe, the water pressure in the water pipe can be ensured to be stable through the overflow cavity, and the depth of the overflow cavity is adjusted. The water pressure in the water pipe can be changed. The leakage hole is located in the transparent box. A sealing plug is provided in the leakage hole. One end of the sealing plug located in the water pipe is connected to a pulling rope. The other end of the pulling rope penetrates into the overflow chamber from the right end of the water pipe. The sealing plug can be pulled out of the water pipe from the right end of the water pipe by pulling the pulling rope, thereby preventing the soil outside the water pipe from leaking into the water pipe before the water flow stabilizes, thereby ensuring the test accuracy. Therefore, the underground pipeline leakage test device of the present invention can simulate the leakage of the underground pipeline and can adjust the water pressure in the water pipe, thereby meeting the test requirements of underground pipeline leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the underground pipeline leakage test device of the present invention;

[0021] Figure 2 It is the right view of the transparent box;

[0022] Figure 3 It is a top view of the transparent box;

[0023] Figure 4 Schematic diagram of a water pipe structure with a sealing plug;

[0024] In the figure, 1. water collecting tank; 11. overflow chamber; 12. partition; 13. second chamber; 2. water pipe; 3. transparent box; 31. first drain hole; 32. second drain hole; 4. sealing plug; 5. pulling rope; 6. pore water pressure gauge; 71. variable frequency water pump; 72. water storage tank; 73. first flow meter; 74. second flow meter; 81. laser transmitter; 82. first camera; 83. second camera; 91. data collector; 92. computer. DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0026] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. It should be understood that the terms "first", "second", etc. are used in the present invention to describe various information, but such information should not be limited to these terms, which are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the "first" information may also be referred to as the "second" information, and similarly, the "second" information may also be referred to as the "first" information.

[0027] like Figures 1 to 4 As shown, a preferred embodiment of the underground pipeline leakage test device of the present invention comprises a water collecting tank 1, a water pipe 2 with a leakage hole on the side wall, a transparent box body 3 with transparent soil and a particle image velocimetry system for photographing the transparent box body 3; the water collecting tank 1 is provided with an overflow chamber 11, the middle part of the water pipe 2 is sealed and penetrated in the lower part of the transparent box body 3, the left end of the water pipe 2 is connected with a water supply device for filling water into the water pipe 2, the right end of the water pipe 2 is connected with the bottom of the overflow chamber 11, the depth of the overflow chamber 11 is adjustable to change the water pressure at the right end of the water pipe 2, the leakage hole is located in the transparent box body 3, a sealing plug 4 is provided in the leakage hole, one end of the sealing plug 4 located in the water pipe 2 is connected with a pulling rope 5, the other end of the pulling rope 5 penetrates into the overflow chamber 11 from the right end of the water pipe 2, and the sealing plug 4 can be pulled out of the water pipe 2 from the right end of the water pipe 2 by pulling the pulling rope 5. Specifically, since the right end of the water pipe 2 is connected to the bottom of the overflow chamber 11, it is only necessary to keep the water depth in the overflow chamber stable to ensure the stability of the water pressure in the water pipe 2. By adjusting the depth of the overflow chamber 11, the water pressure in the water pipe 2 can be changed. The overflow chamber 11 realizes the adjustment and stabilization of the water pressure in the water pipe 2, and the structure is simple and the cost is low. By pulling the pulling rope 5, the sealing plug 4 can be pulled out of the water pipe 2 from the right end of the water pipe 2, thereby preventing the soil outside the water pipe 2 from leaking into the water pipe 2 before the water flow stabilizes, thereby ensuring the test accuracy. Therefore, the underground pipeline leakage test device of the present invention can simulate underground pipeline leakage, and can adjust the water pressure in the water pipe, meeting the test requirements of underground pipeline leakage.

[0028] Among them, organic glass plates are used on all four sides of the transparent water tank, the water pipe 2 is an organic glass tube, the water pipe 2 is buried in the transparent box body 3, the water collecting tank 1 includes a water collecting tank body, and a partition 12 is sealed and inserted in the middle of the water collecting tank body. The partition 12 divides the inner cavity of the water collecting tank body into a first cavity and a second cavity 13. The first cavity forms an overflow cavity 11, and the partition 12 can be extended and retracted up and down to adjust the depth of the overflow cavity 11. Specifically, in the present embodiment, a first cavity is formed on the left side of the partition 12, and a second cavity 13 is formed on the right side of the partition 12. The partition 12 includes a plurality of sub-plates that can be extended and retracted up and down. The sub-plates are sequentially fitted from left to right, and a guide structure is provided between two adjacent sub-plates. The two adjacent sub-plates on the left and right are provided as a left plate and a right plate. The widths of the left plate and the right plate match the width of the overflow cavity 11 in the front-to-back direction. The right side surface of the left plate is provided with a dovetail guide rail arranged up and down, and the left side of the right plate is provided with a dovetail groove matching the dovetail guide rail, so that the left plate and the right side plate can be extended and retracted up and down.

[0029] The water overflowing from the overflow chamber 11 flows into the second chamber 13, and the bottom of the second chamber 13 is connected to the water inlet of the water supply device, so that the water flowing out of the overflow chamber 11 can flow back to the water supply device to achieve the recycling of water flow.

[0030] Specifically, the water supply device includes a variable frequency water pump 71 and a water tank 72. The inlet end of the variable frequency water pump 71 is connected to the water tank 72, and the outlet end of the variable frequency water pump 71 is connected to the left end of the water pipe 2. A first flow meter 73 for measuring the water flow velocity at the upstream position of the water leak hole is provided between the variable frequency water pump 71 and the water leak hole. The second cavity 13 is connected to the water tank 72 through a pipeline. The water flow velocity in the water pipe 2 can be known through the first flow meter 73, avoiding the adverse effect of the unstable water flow velocity on the test.

[0031] Furthermore, the water pipe 2 is provided with a second flow meter 74 for measuring the water flow velocity at the downstream position of the water leakage hole at a position between the water leakage hole and the right end of the water pipe 2. The flow velocity upstream and downstream of the water leakage hole can be known by the first flow meter 73 and the second flow meter 74, further improving the test accuracy.

[0032] In this embodiment, a plurality of pore water pressure gauges 6 are arranged at intervals on the inner side wall of the transparent box 3, and the pressure change values ​​at different height positions of the transparent image in the transparent box can be known through the pore water pressure gauges 6. Specifically, the pore water pressure gauges 6 are pasted on the inner side of the transparent box 3, and the underground pipeline leakage test device includes a data collector 91 and a computer 92 electrically connected to the data collector 91, and each pore water pressure gauge 6 is electrically connected to the data collector 91. In order to facilitate the drainage of water in the transparent box 3 after the test, a first drainage hole 31 is provided at the bottom of the transparent box 3, and a plurality of second drainage holes 32 are provided at intervals on the side wall of the transparent box 3, and the first drainage hole 31 and each second drainage hole 32 are plugged with a rubber plug.

[0033] In this embodiment, the particle image velocimetry system includes a laser emitter 81, a first camera 82 and a second camera 83. The laser emitter 81 is located on the left side of the transparent box 3, the first camera 82 is located on the right side of the transparent box 3, and the second camera 83 is located in front of the transparent box 3.

[0034] A method for using the above-mentioned underground pipeline leakage test device comprises the following steps:

[0035] Step S1, adding transparent soil with a specific particle size distribution into the transparent box 3;

[0036] Step S2, turning on the water supply device, so that water flows into the overflow chamber 11 through the water pipe 2, until the overflow chamber 11 is filled with water and overflows stably;

[0037] Step S3, pulling the pulling rope 5, pulling the sealing plug 4 out of the leaking hole, and photographing it through the particle image velocimetry system.

[0038] Step S4, adjust the depth of the overflow cavity, and repeat steps S1 to S3.

[0039] In step S3, the sealing plug 4 is pulled out from the leaking hole after the values ​​of the first flow meter 73 and the second flow meter 74 are stabilized.

[0040] Specifically, the water pipe 2 is connected to the transparent box 3 in a detachable manner. Before the test, the water pipe 2 is first inserted into the transparent box 3, and then the connection seam between the water pipe 2 and the transparent box 3 is sealed with silicone. Then, rubber plugs are inserted into the first drainage hole 31 and each second drainage hole 32 to seal the surrounding side and bottom of the transparent box 3. Then, transparent soil and pore fluid of a certain grade are layered and filled into the transparent box 3 to appropriate positions, and then left to stand until the transparent soil in the transparent box 3 is saturated; then, the variable frequency water pump 71 is turned on to allow water to flow into the overflow chamber 11 through the water pipe 2 until the overflow chamber 11 is filled with water and overflows stably. After the values ​​of the first flow meter 73 and the second flow meter 74 are stable, the sealing plug 4 is pulled out of the leaking hole to simulate the leakage process of the water supply pipe. After the destruction is completed, stop filming, perform digital image processing on the filmed video, and obtain the soil destruction process caused by water supply pipe leakage and its particle movement path; thereafter, adjust the particle gradation of the transparent soil in the transparent box 3, and repeat the sampling steps: fill transparent soil particles of a certain gradation and pore fluid into the transparent box 3 in layers to the appropriate position, then let it stand until the soil in the transparent box 3 is saturated, and conduct a leakage test again, and compare it with the data under the first geological condition, until enough images and data of the soil destruction process caused by water pipe leakage with particle grading are obtained, and a three-dimensional leakage model is established by slicing and recombining images, and the soil destruction process and related data under different particle gradings are compared to find the optimal particle grading of backfill soil for water supply pipe construction, and use this as a basis to guide the actual water supply pipeline backfill construction.

[0041] In summary, the underground pipeline leakage test device of the present invention comprises a water collecting tank 1, a water pipe 2 with a leakage hole on the side wall, a transparent box body 3 with transparent soil and a particle image velocimetry system for photographing the transparent box body 3; the water collecting tank 1 is provided with an overflow chamber 11, the middle part of the water pipe 2 is sealed and penetrated in the lower part of the transparent box body 3, the left end of the water pipe 2 is connected with a water supply device for filling water into the water pipe 2, the right end of the water pipe 2 is connected with the bottom of the overflow chamber 11, the depth of the overflow chamber 11 is adjustable to change the water pressure at the right end of the water pipe 2, the leakage hole is located in the transparent box body 3, a sealing plug 4 is provided in the leakage hole, one end of the sealing plug 4 located in the water pipe 2 is connected with a pulling rope 5, the other end of the pulling rope 5 penetrates into the overflow chamber 11 from the right end of the water pipe 2, and the sealing plug 4 can be pulled out of the water pipe 2 from the right end of the water pipe 2 by pulling the pulling rope 5. Specifically, since the right end of the water pipe 2 is connected to the bottom of the overflow chamber 11, it is only necessary to keep the water depth in the overflow chamber stable to ensure the stability of the water pressure in the water pipe 2. By adjusting the depth of the overflow chamber 11, the water pressure in the water pipe 2 can be changed. The overflow chamber 11 realizes the adjustment and stabilization of the water pressure in the water pipe 2, and the structure is simple and the cost is low. By pulling the pulling rope 5, the sealing plug 4 can be pulled out of the water pipe 2 from the right end of the water pipe 2, thereby preventing the soil outside the water pipe 2 from leaking into the water pipe 2 before the water flow stabilizes, thereby ensuring the test accuracy. Therefore, the underground pipeline leakage test device of the present invention can simulate underground pipeline leakage, and can adjust the water pressure in the water pipe, meeting the test requirements of underground pipeline leakage. The underground pipeline leakage test device of the present invention can simulate stable water supply pressures of different sizes; and by rotating the water pipe 2 to different angles, it can simulate the working conditions of different spatial distributions of water supply pipeline leakage ports; the pore water pressure gauge 6 inside the transparent box 3 tests the pore water pressure at different positions, which can meet the needs of observing the spatial distribution of pore water pressure in the soil sample and the time evolution characteristic test. By replacing the leaking water pipes 2 with different sizes, it is possible to simulate the working conditions of different water supply pipeline leakage port sizes; by collecting test images with two digital cameras of the shooting system, and using the slice three-dimensional reconstruction technology, it is possible to analyze and obtain the three-dimensional motion state of transparent soil particles when the water supply pipeline leaks, as well as the changes in the hydraulic gradient inside the soil body after the water supply pipe leaks. Three-dimensional experimental research is realized on the basis of laser speckle two-dimensional imaging, which effectively avoids the boundary effect produced by similar model tests. At the same time, it is not limited to the study of water pressure inside the pipe, and the study of the hydraulic changes inside the soil body under this working condition is realized, which proposes a systematic and perfect research device for the study of water supply pipeline leakage problems.

[0042] 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 substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. An underground pipeline leakage test device, characterized in that: The invention comprises a water collecting box (1), a water pipe (2) with a leaking hole on the side wall, a transparent box (3) with transparent soil, and a particle image velocimetry system for photographing the transparent box (3); the water collecting box (1) is provided with an overflow chamber (11); the middle part of the water pipe (2) is sealed and penetrated through the lower part of the transparent box (3); the left end of the water pipe (2) is connected to a water supply device for filling the water pipe (2); the right end of the water pipe (2) is connected to the bottom of the overflow chamber (11); the depth of the overflow chamber (11) is adjustable to change the water pressure at the right end of the water pipe (2); the leaking hole is located in the transparent box (3); a sealing plug (4) is provided in the leaking hole; the sealing plug (4) is One end of the sealing plug (4) located in the water pipe (2) is connected to a pulling rope (5), and the other end of the pulling rope (5) penetrates into the overflow chamber (11) from the right end of the water pipe (2). By pulling the pulling rope (5), the sealing plug (4) can be pulled out of the water pipe (2) from the right end of the water pipe (2); the water supply device comprises a variable frequency water pump (71) and a water storage tank (72), the inlet end of the variable frequency water pump (71) is connected to the water storage tank (72), the outlet end of the variable frequency water pump (71) is connected to the left end of the water pipe (2), and a first flow meter (73) for measuring the water flow velocity at the upstream position of the water leakage hole is provided between the variable frequency water pump (71) and the water leakage hole; The water pipe (2) is provided with a second flow meter (74) at a position between the water leakage hole and the right end of the water pipe (2) for measuring the flow velocity of water at a position downstream of the water leakage hole; After the values ​​of the first flow meter (73) and the second flow meter (74) are stable, the sealing plug (4) is pulled out from the water leakage hole; The water collecting box (1) comprises a water collecting box body, a partition (12) is sealed and inserted in the middle of the water collecting box body, the partition (12) divides the inner cavity of the water collecting box body into a first cavity and a second cavity (13), the first cavity forms the overflow cavity (11), and the partition (12) can be extended and retracted up and down to adjust the depth of the overflow cavity (11); the partition (12) comprises a plurality of sub-plates that can be extended and retracted up and down, each of the sub-plates is sequentially fitted from left to right, and a guide structure is provided between two adjacent sub-plates.

2. The underground pipeline leakage test device according to claim 1, characterized in that: The bottom of the second cavity (13) is in communication with the water inlet end of the water supply device.

3. The underground pipeline leakage test device according to claim 1, characterized in that: A plurality of pore water pressure gauges (6) are arranged at intervals above and below the inner side wall of the transparent box (3).

4. The underground pipeline leakage test device according to claim 1, characterized in that: The particle image velocimetry system comprises a laser emitter (81), a first camera (82) and a second camera (83), wherein the laser emitter (81) is located on the left side of the transparent box (3), the first camera (82) is located on the right side of the transparent box (3), and the second camera (83) is located in front of the transparent box (3).

5. The underground pipeline leakage test device according to claim 1, characterized in that: The water pipe (2) is a plexiglass pipe.

6. A method for using the underground pipeline leakage test device according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step S1, adding transparent soil into the transparent box (3); Step S2, turning on the water supply device, so that water flows into the overflow chamber (11) through the water pipe (2), until the overflow chamber (11) is filled with water and overflows stably; Step S3, pulling the pulling rope (5) to pull the sealing plug (4) out of the leaking hole, and photographing it through a particle image velocimetry system; Step S4, adjusting the depth of the overflow cavity, and repeating steps S1 to S3.

7. The method for using the underground pipeline leakage test device according to claim 6, characterized in that: In the step S3, the sealing plug (4) is pulled out from the water leakage hole after the values ​​of the first flow meter (73) and the second flow meter (74) are stabilized.

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