Buried drainage pipe seepage test device and method for simulating adjustable interface defects

Abstract

The present application relates to geotechnical engineering and municipal drainage pipeline test technical field, disclose a kind of buried drainage pipeline seepage test device and method of simulating adjustable interface defect, device includes test soil box, short pipe, test pipe, frame type pipeline support assembly and overflow porous plate, test soil box is provided with transparent plate, short pipe, test pipe is fixed in transparent plate and opposite side plate;Frame type pipeline support assembly includes lifting piece, locking piece and horizontal position driving piece, for driving test pipe relative short pipe carries out vertical and horizontal displacement adjustment, to simulate interface defect;Overflow porous plate forms independent water tank, matched with water supply water tank component to control hydraulic boundary;Device also includes water sand collection monitoring component, curved surface diversion slope plate and camera, for water sand collection, seepage data monitoring and soil deformation process observation.The present application can be used for seepage and sand transport test under the condition of buried drainage pipeline interface defect, to provide test support for interface defect state and seepage response relationship research.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering and municipal drainage pipeline testing technology, and in particular to a test device and method for simulating seepage in buried drainage pipelines with adjustable interface defects. Background Technology

[0002] In recent years, with the increasing service life of urban drainage pipe networks, and the combined effects of uneven foundation settlement, fluctuations in construction quality, and traffic loads, defects such as misalignment, disconnection, and vertical undulations are prone to occur at the joints of buried drainage pipes. These defects can lead to groundwater seepage into the pipe, increasing the load on drainage and sewage treatment systems and raising the risk of overflow. Furthermore, sewage may seep out of the pipe, polluting the surrounding soil and groundwater environment, weakening the stability of the surrounding soil, and potentially causing cavitation, surface subsidence, and even road collapse – all engineering safety issues. Therefore, establishing a quantitative relationship between the defect status of buried drainage pipe joints and seepage response is crucial for assessing the operational status of drainage pipe networks and developing trenchless repair solutions.

[0003] Existing engineering inspection methods, such as closed-circuit television (CCTV) inspection, sonar inspection, and laser scanning, are mainly used to obtain information on the geometric morphology and apparent defects of pipe joints. They are difficult to directly obtain the seepage flow and sediment transport response corresponding to different defect levels under controlled conditions. On the other hand, existing indoor testing equipment focuses on the study of pipe stress performance or structural performance. It is still insufficient for simulating the seepage and sediment transport process under the condition of defects in buried drainage pipe joints. This is usually manifested in the relatively simple loading method of joint defects, unstable hydraulic boundary control, poor repeatability of test conditions, and difficulty in carrying out relevant experimental research systematically.

[0004] Furthermore, traditional seepage tests often rely on measuring the seepage water and particle loss using graduated cylinders, measuring cups, or manual sampling and weighing. These methods suffer from insufficient measurement continuity, large data dispersion, and low automation, making it difficult to accurately obtain the correlation between interface defect states and seepage responses. Therefore, it is necessary to provide a device and method capable of adjustable simulation of interface defects in buried drainage pipes and conducting seepage and sediment transport tests under controlled hydraulic boundary conditions. Summary of the Invention

[0005] The present invention aims to provide a test device and method for simulating seepage in buried drainage pipelines with adjustable interface defects, so as to solve, to some extent, the problems in the prior art such as the single loading method for interface defects in buried drainage pipelines, unstable hydraulic boundary control, and difficulty in continuous measurement of seepage and sand transport processes.

[0006] To achieve the above objectives, a first aspect of the present invention provides a test apparatus for simulating seepage in buried drainage pipes with adjustable interface defects, comprising: The test soil box has at least one transparent panel on one side. A short tube passes through the transparent plate and is fixed to the transparent plate; The test tube is fixed through and to the side plate of the test soil box, which is opposite to the transparent plate. A frame-type pipe support assembly includes a lifting component and a locking component connected to the lifting component. The locking component is fixedly connected to one end of the test tube located inside the test soil box. The lifting component is used to drive one end of the test tube located inside the test soil box to move relative to one end of the short pipe located inside the test soil box in the height direction. At least one overflow perforated plate is installed inside the test soil box, and an independent water trough is formed between the overflow perforated plate and one side plate of the test soil box. The overflow perforated plate is provided with several overflow holes.

[0007] Through the above technical solution, the lifting component can drive the test tube to move vertically relative to the short tube, thereby simulating the defects of the pipe interface; at the same time, with the help of the overflow perforated plate and the independent water tank, a relatively stable hydraulic boundary condition can be formed in the test soil box, thereby providing a basic test platform for seepage test under the condition of buried drainage pipe interface defects.

[0008] In one alternative embodiment, the elevation of the mounting holes on the transparent plate on which the short tube is mounted is lower than the elevation of the mounting holes on the side plate on which the test tube is mounted.

[0009] In one alternative implementation, it further includes: A transparent variable diameter disc is installed in the mounting hole on the transparent plate; The second reducing plate is installed in the mounting hole on the side plate; Both the transparent reducing plate and the second reducing plate include an outer circular outer flange and an inner stepped flange. The outer circular outer flange is fixedly connected to the transparent plate or the side plate. The thickness and outer diameter of the inner stepped flange are respectively adapted to the thickness and diameter of the corresponding mounting hole.

[0010] In one optional embodiment, the frame-type pipe support assembly further includes a lateral position drive component connected between the lifting component and the locking component. The lateral position drive is used to drive one end of the test tube inside the test soil box to move closer to or further away from the other end of the short tube inside the test soil box.

[0011] In one alternative embodiment, the lateral position drive includes: The slider adjustment box is fixedly connected to the lifting component; An offset adjustment servo motor is fixed inside the slider adjustment box; The offset lead screw is rotatably mounted inside the slider adjustment box. One end of the screw is connected to the drive end of the offset adjustment servo motor through a bearing connector, and the other end is rotatably connected to the inner wall of the slider adjustment box. A pair of slide rails are fixed inside the slider adjustment box, and the slide rails are arranged parallel to the offset screw; The slider adjustment box has a rectangular through hole on the side facing the locking member, and the locking member is connected to the offset screw and the slide rail through the rectangular through hole.

[0012] In one alternative implementation, the locking element includes: A support fixing arm is provided with a threaded rectangular component at its lower part, and the threaded rectangular component is threadedly engaged with the offset screw. The pipe clamp half-ring is connected to the other end of the support fixing arm; The binding strap is connected at both ends to the two ends of the tube clamp half-ring, respectively; The tube clamp half-ring and the binding strap form a closed loop to secure the test tube.

[0013] In one optional embodiment, the lifting member includes: The base is fixedly connected to the bottom of the test soil box; The lifting screw is rotatably mounted inside the base; A limiting protrusion is provided at the top of the lifting screw, and a limiting groove is provided at the bottom of the slider adjustment box, wherein the limiting protrusion is limited to the limiting groove; A lifting servo motor, wherein the drive end of the lifting servo motor is connected to the lifting lead screw via a coupling; A transparent telescopic tube cover is fitted around the outer periphery of the lifting screw, and the upper and lower ends of the transparent telescopic tube cover are fixedly connected to the base and the slider adjustment box, respectively.

[0014] In one optional embodiment, the base includes an upper rectangular frame, a lower rectangular frame, and a hollow cylindrical column connected between the upper rectangular frame and the lower rectangular frame, and the lifting screw is rotatably disposed inside the hollow cylindrical column. The lifting component is provided in two parts, and an adjustable toothed connector is provided between the bases of the two lifting components.

[0015] In one optional embodiment, two overflow perforated plates are provided, and the two overflow perforated plates are respectively arranged on opposite sides of the test soil box, dividing the test soil box into two independent water tanks; The test apparatus also includes a water supply tank assembly, which comprises: Water tank; A circulating water pump is installed inside the water tank; A water supply pipe connects the circulating water pump to the independent water tank; A control valve is connected to the water supply pipe; A water level balancing pipe is connected to the two independent water tanks at the same height; Two level gauges are respectively installed in the two independent water tanks.

[0016] In one alternative implementation, it further includes: A water and sand collection box is installed at the outlet end of the short pipe; A filter baffle is installed inside the water and sand collection box; An electronic scale is installed at the bottom of the water and sand collection tank; A pressure-type liquid level sensor is installed inside the bottom side of the water and sand collection tank; A camera is mounted on one side of the water and sand collection tank.

[0017] In one alternative embodiment, a curved guide slope plate is also included, fixed to the test soil box and located below the end of the short pipe located outside the test soil box; The curved guide slope plate is an arc-shaped plate with its arc surface facing the water and sand collection box.

[0018] A second aspect of the present invention also provides a method for simulating seepage tests on buried drainage pipes with adjustable interface defects, comprising the following steps: Prepare a test soil box and install overflow perforated plates on opposite sides of the test soil box; A frame-type pipe support assembly is arranged at the bottom of the test soil box. A short pipe is installed and fixed through the transparent plate of the test soil box, and a test pipe is installed and fixed through the side plate of the test soil box opposite to the transparent plate. The test pipe is fixed to the frame-type pipe support assembly, and the two pipe interfaces are made to fit together. Soil was filled inside the test soil box, and sensors were installed. Water is supplied to the independent water tank; At least one defect condition is applied to the interface between the test pipe and the short pipe through the frame-type pipe support assembly, and the corresponding displacement or misalignment is recorded. Collect the water and solid particles flowing out of the short pipe, and after completing the tests of each working condition, gradually lower the water level, and weigh, dry and classify the collected water and solid particles; then excavate the soil layer by layer from top to bottom.

[0019] Through the above technical solution, the present invention can simulate the interface defects of buried drainage pipes under indoor conditions and carry out seepage and sand transport tests under controlled hydraulic boundary conditions, providing experimental means for studying the relationship between interface defect state and seepage response. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a front perspective view of the buried drainage pipeline seepage test device for simulating adjustable interface defects according to an embodiment of the present invention. Figure 2 This is a rear perspective view of the buried drainage pipeline seepage test device for simulating adjustable interface defects according to an embodiment of the present invention. Figure 3 This is a top view of the buried drainage pipeline seepage test device for simulating adjustable interface defects according to an embodiment of the present invention; Figure 4 This is a three-dimensional schematic diagram of the variable diameter plate in the buried drainage pipeline seepage test device for simulating adjustable interface defects according to an embodiment of the present invention. Figure 5 This is a front view of the frame-type pipe support assembly in the buried drainage pipe seepage test device for simulating adjustable interface defects according to an embodiment of the present invention. Figure 6 for Figure 5 AA section view in the middle; Figure 7 for Figure 5 Partial cross-sectional view of BB in the middle; Figure 8 This is a three-dimensional schematic diagram of the slider adjustment box in the buried drainage pipeline seepage test device for simulating adjustable interface defects according to an embodiment of the present invention. Figure 9 This is a schematic diagram of the combination of the frame-type pipe support assembly and the test pipe in the buried drainage pipe seepage test device for simulating adjustable interface defects according to an embodiment of the present invention. Figure 10 This is a three-dimensional schematic diagram of the short pipe in the buried drainage pipeline seepage test device for simulating adjustable interface defects according to an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures: 1. Test soil box; 11. Steel box body; 12. Transparent plate; 13. Front plate reinforcing steel bars; 14. Overflow perforated plate; 15. Box body overflow hole; 16. Transparent variable diameter plate; 17. Second variable diameter plate; 18. Variable diameter plate fixing bolts; 19. Curved guide slope plate; 2. Frame-type pipe support assembly; 21. Base; 22. Adjustable toothed connector; 23. Anchor bolts; 24. Lifting servo motor; 25. Lifting screw; 26. Transparent telescopic pipe cover; 27. Limiting protrusion; 3. Pipe clamp assembly; 31. Slider adjustment box; 32. Support fixing arm; 33. Pipe clamp half ring; 34. Binding strap; 35. Threaded rectangular component; 36. Offset adjustment servo motor; 37. Coupling; 38. Offset lead screw; 39. Slide rail; 4. Test tubes; 5. Short pipe; 51. Annular groove; 6. Water and sand collection tank; 61. Filter baffle; 62. Electronic scale; 63. Pressure level sensor; 7. Water supply tank assembly; 71. Water tank; 72. Circulating water pump; 73. Water supply pipe; 74. Control valve; 75. Water level balancing pipe; 8. Camera; 9. Level gauge. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] like Figures 1 to 10As shown, this embodiment provides a buried drainage pipeline seepage test device for simulating adjustable interface defects, including a test soil box 1, a short pipe 5, a test pipe 4, a frame-type pipe support assembly 2, and at least one overflow perforated plate 14. At least one side panel of the test soil box 1 is a transparent plate 12, specifically a transparent front panel. The short pipe 5 passes through the transparent plate 12 and is fixed to it; the test pipe 4 passes through and is fixed to the side panel of the test soil box 1 opposite to the transparent plate 12; the frame-type pipe support assembly 2 includes a lifting component and a locking component connected to the lifting component. The locking component is fixedly connected to one end of the test pipe 4 located inside the test soil box 1. The lifting component is used to drive the end of the test pipe 4 located inside the test soil box 1 to move relative to the end of the short pipe 5 located inside the test soil box 1 in the height direction; the overflow perforated plate 14 is disposed inside the test soil box 1 and forms an independent water tank with one side panel of the test soil box 1; the overflow perforated plate 14 is provided with several overflow holes.

[0025] In this embodiment, the test soil box 1 is a steel welded box structure with high overall rigidity and strong pressure-bearing capacity. The front side plate of the test soil box 1 is a transparent plate 12, which can be made of high-strength transparent plexiglass and is assembled with the steel box body 11 through a slot to ensure the pressure-bearing performance of the test soil box 1 while allowing observation of the seepage process and soil changes inside the box.

[0026] Preferably, in order to improve the stability of the transparent plate 12 under pressure conditions, several front plate reinforcing steel bars 13 can be inserted into its outer side along the horizontal direction. The front plate reinforcing steel bars 13 are connected to the steel box body 11 through end slots. Figure 3 The partial sectional view in the figure shows the assembly relationship between the steel box 11, the transparent plate 12, the front plate reinforcing steel strip 13 and the overflow perforated plate 14.

[0027] A short pipe 5 penetrates the transparent plate 12 of the test soil box 1 and is fixedly connected to the transparent plate 12. The end of the short pipe 5 located outside the test soil box 1 is used to connect to the test-related pipelines, while the end located inside the test soil box 1 faces the internal space of the test soil box 1, forming a connection end for the pipeline interface. A test pipe 4 penetrates the rear side plate of the test soil box 1, which is opposite to the transparent plate 12, and is sealed and fixed to the side plate. The end of the test pipe 4 located inside the test soil box 1 and the end of the short pipe 5 located inside the test soil box 1 are positioned opposite each other, forming a pipeline interface area for simulating the defect; the end of the test pipe 4 located outside the test soil box 1 is used for connecting and fixing the test-related pipelines.

[0028] The frame-type pipe support assembly 2 is installed on the inner bottom plate of the test soil box 1. The assembly includes a lifting component and a locking component connected to the lifting component. The locking component is fixedly connected to the pipe section of the test pipe 4 located inside the test soil box 1, and is used to achieve circumferential restriction and vertical support of the test pipe 4. The lifting component is fixedly connected to the bottom plate of the test soil box 1, and can generate linear displacement in the vertical direction. Through the locking component, it drives one end of the test pipe 4 located inside the test soil box 1 to move vertically relative to one end of the short pipe 5 located inside the test soil box 1, so as to simulate the defect state of pipe joint misalignment, vertical undulation, etc.

[0029] The overflow perforated plate 14, made of high-strength steel plate, is installed inside the test soil tank 1. An independent water tank, isolated from the inner side plate of the test soil tank 1, is formed between the overflow perforated plate 14 and the inner side plate. This independent water tank stores test water to provide a hydraulic boundary simulating groundwater seepage for the surrounding soil. The overflow perforated plate 14 has several overflow holes evenly distributed on it. These overflow holes serve both permeability and soil-blocking functions, allowing water in the water tank to evenly seep into the soil within the test soil tank 1, while reducing the possibility of soil particles entering the water tank. Furthermore, multiple overflow holes 15 are evenly distributed along the height direction on the steel plates on both sides of the test soil tank 1 to overflow and drain water when the water level exceeds a set height, preventing abnormal rise in water head.

[0030] Through the above structure, the lifting component can drive the test pipe 4 to move vertically relative to the short pipe 5, thereby adjusting the relative positional relationship at the pipe joint to simulate joint misalignment or undulation defects. Combined with the transparent observation surface of the test soil box 1 and the hydraulic boundary formed by the overflow perforated plate 14, the simulation and observation of the seepage process under buried drainage pipe joint defects can be realized under indoor conditions.

[0031] In one embodiment, the elevation of the mounting hole on the transparent plate 12 on which the short tube 5 is mounted is lower than the elevation of the mounting hole on the side plate on which the test tube 4 is mounted.

[0032] Specifically, the transparent plate 12 on the test soil box 1, used for installing the short pipe 5, has a first mounting hole. The short pipe 5 passes through the first mounting hole and is fixedly sealed with the transparent plate 12. The side plate used for installing the test pipe 4 has a second mounting hole. The test pipe 4 passes through the second mounting hole and is fixedly sealed with the side plate. The elevation of the first mounting hole is lower than the elevation of the second mounting hole, so that the short pipe 5 and the test pipe 4 form a unidirectional slope inclined towards the side of the short pipe 5 within the test soil box 1.

[0033] Based on the above-mentioned installation hole elevation setting, during the test, the water seeping from the pipe interface defect and the particulate medium it carries can flow along the unidirectional slope to the side of the short pipe 5 under the action of gravity, thereby reducing the accumulation of seepage medium in the soil around the pipe and at the interface, which is beneficial for subsequent collection of seepage-related data and reduces the impact of seepage medium accumulation on the test conditions.

[0034] In one embodiment, the buried drainage pipe seepage test device simulating adjustable interface defects further includes a transparent reducing plate 16 and a second reducing plate 17. The transparent reducing plate 16 is installed in a mounting hole on the transparent plate 12; the second reducing plate 17 is installed in a mounting hole on the side plate; both the transparent reducing plate 16 and the second reducing plate 17 include an outer circular flange and an inner stepped flange, the outer circular flange is fixedly connected to the transparent plate 12 or the side plate, and the thickness and outer diameter of the inner stepped flange are adapted to the thickness and diameter of the corresponding mounting hole, respectively.

[0035] The transparent reducing plate 16 is installed in the first mounting hole of the transparent plate 12 of the test soil tank 1, providing positioning, support, and sealing structure for the short pipe 5. After the short pipe 5 passes through the inner through hole of the transparent reducing plate 16, it forms a sealed and fixed connection with the transparent reducing plate 16. The transparent reducing plate 16 can adopt an integrally formed stepped annular flange structure, including an outer circular flange and an inner stepped flange. The outer circular flange is fitted to the outer surface of the transparent plate 12, and several bolt holes are opened on the flange. The reducing plate fixing bolts 18 pass through the bolt holes and are connected to the transparent plate 12 to achieve positioning and fixing of the transparent reducing plate 16 at the first mounting hole; the inner stepped flange extends towards the inside of the test soil tank 1, and its thickness matches the wall thickness of the first mounting hole on the transparent plate 12, and its outer diameter matches the inner diameter of the first mounting hole.

[0036] The second reducing plate 17 is installed in the second mounting hole of the side plate opposite to the transparent plate 12 of the test soil tank 1, and is used to provide positioning, support and sealing structure for the test tube 4. After the test tube 4 passes through the inner through hole of the second reducing plate 17, it forms a sealed fixation with the second reducing plate 17. The second reducing plate 17 can adopt the same or similar stepped circular flange structure as the transparent reducing plate 16, including an outer circular flange and an inner stepped flange. The outer circular flange is fitted to the outer surface of the rear side plate of the test soil tank 1, and several bolt holes are opened on the flange. The reducing plate fixing bolts 18 pass through the bolt holes and are connected to the rear side plate to realize the positioning and fixation of the second reducing plate 17 at the second mounting hole; the thickness of the inner stepped flange matches the wall thickness of the second mounting hole, and the outer diameter matches the inner diameter of the second mounting hole.

[0037] By separately setting the transparent reducing plate 16 and the second reducing plate 17, independent installation structures can be provided for the short pipe 5 and the test pipe 4. By replacing the transparent reducing plate 16 or the second reducing plate 17 with different inner through-hole diameters, short pipes 5 and test pipes 4 with different diameters can be adapted without modifying the mounting holes of the test soil box 1, thereby improving the adaptability of the test device to pipes of different diameters.

[0038] In one embodiment, the frame-type pipe support assembly 2 further includes a lateral position drive component connected between the lifting component and the locking component; the lateral position drive component is used to drive one end of the test pipe 4 located inside the test soil box 1 to approach or move away from the end of the short pipe 5 located inside the test soil box 1.

[0039] In this embodiment, the frame-type pipe support assembly 2 adds a lateral position drive component to the lifting component and locking component, forming a connection structure of "lifting component - lateral position drive component - locking component". The lifting component can generate linear displacement in the vertical direction and transmit the force to the locking component through the lateral position drive component, thereby driving one end of the test pipe 4 located inside the test soil box 1 to move vertically to simulate defects such as misalignment and vertical undulation of the pipe interface; the lateral position drive component can generate linear displacement in the horizontal direction, thereby driving one end of the test pipe 4 located inside the test soil box 1 to move closer to or further away from the end of the short pipe 5 located inside the test soil box 1 in the horizontal direction to simulate horizontal misalignment defects of the pipe interface, and can be linked with the lifting component to realize composite misalignment conditions.

[0040] In one embodiment, the lateral position drive includes a slider adjustment box 31, an offset adjustment servo motor 36, an offset lead screw 38, and a pair of slide rails 39. The slider adjustment box 31 is fixedly connected to the lifting component; the offset adjustment servo motor 36 is fixed inside the slider adjustment box 31; the offset lead screw 38 is rotatably disposed inside the slider adjustment box 31, with one end connected to the drive end of the offset adjustment servo motor 36 via a bearing connector, and the other end rotatably connected to the inner wall of the slider adjustment box 31; the pair of slide rails 39 are fixed inside the slider adjustment box 31 and are arranged parallel to the offset lead screw 38; the slider adjustment box 31 has a rectangular through hole on the side facing the locking component, and the locking component is connected to the offset lead screw 38 and the slide rails 39 through the rectangular through hole.

[0041] The slider adjustment box 31 is fixedly connected to the top of the lifting component and serves as the mounting carrier for the various components of the lateral position drive component. The offset adjustment servo motor 36 is installed in the internal cavity of the slider adjustment box 31 and provides power for the horizontal displacement of the test tube 4. The offset screw 38 is located inside the slider adjustment box 31, with one end connected to the offset adjustment servo motor 36 via a bearing connector, and the other end rotatably connected to the inner wall of the slider adjustment box 31. A pair of slide rails 39 are arranged parallel to each other inside the slider adjustment box 31, with their extension direction consistent with the axial direction of the offset screw 38, and are used to guide the horizontal sliding of the locking component. The locking component extends into the slider adjustment box 31 through the rectangular through hole, forming a threaded engagement with the offset screw 38 and a guiding engagement with the pair of slide rails 39.

[0042] Preferably, to improve sealing and protection performance, an annular mounting groove can be provided around the rectangular through hole, and a rubber sealing strip or flexible sealing curtain can be embedded in the groove to reduce the possibility of external water, soil particles and impurities entering the slider adjustment box 31.

[0043] In this embodiment, after the offset adjustment servo motor 36 is started, it outputs rotational power and transmits it to the offset screw 38 through the bearing connector, causing the offset screw 38 to rotate. Since the locking member is threadedly engaged with the offset screw 38 and guided by the slide rail 39, the rotational motion of the offset screw 38 can be converted into the horizontal linear motion of the locking member along the slide rail 39, thereby causing the end of the test tube 4 located inside the test soil box 1 to move closer to or further away from the end of the short tube 5 located inside the test soil box 1 in the horizontal direction.

[0044] In one embodiment, the locking element includes a support fixing arm 32, a pipe clamp half-ring 33, and a binding strap 34. A threaded rectangular member 35 is provided at the lower part of the support fixing arm 32, the threaded rectangular member 35 being threadedly engaged with an offset screw 38; the pipe clamp half-ring 33 is connected to the other end of the support fixing arm 32; both ends of the binding strap 34 are respectively connected to both ends of the pipe clamp half-ring 33; the pipe clamp half-ring 33 and the binding strap 34 form a closed loop to fix the test tube 4.

[0045] Specifically, the support fixing arm 32 forms a threaded engagement with the offset screw 38 through the threaded rectangular member 35 at its lower part, and is guided by a pair of slide rails 39 inside the slider adjusting box 31, so that it can move horizontally linearly along the slide rails 39 as the offset screw 38 rotates. The pipe clamp half ring 33 can adopt a semi-ring structure that matches the outer diameter of the test tube 4, and its arc-shaped inner side is set against the outer wall of the test tube 4. The two ends of the binding strap 34 are respectively connected to the two ends of the pipe clamp half ring 33, so that together with the pipe clamp half ring 33, they form a closed ring for fixing the test tube 4.

[0046] With the above structure, the locking component can be linked with the lateral position drive component, and at the same time, it can form a relatively stable fixation on the test tube 4, so that the displacement generated by the lifting component and the lateral position drive component can be transmitted to the test tube 4.

[0047] In one embodiment, the lifting component includes a base 21, a lifting screw 25, a limiting protrusion 27, a lifting servo motor 24, and a transparent telescopic tube cover 26. The base 21 is fixed to the bottom of the test soil box 1; the lifting screw 25 is rotatably disposed within the base 21; the limiting protrusion 27 is disposed on the top of the lifting screw 25, and the bottom of the slider adjustment box 31 is provided with a limiting groove, wherein the limiting protrusion 27 is limited within the limiting groove; the drive end of the lifting servo motor 24 is connected to the lifting screw 25 via a coupling 37; the transparent telescopic tube cover 26 is sleeved on the outer periphery of the lifting screw 25, and its upper and lower ends are respectively fixedly connected to the base 21 and the slider adjustment box 31.

[0048] In this embodiment, the base 21 serves as the mounting foundation and support structure for all components of the lifting mechanism, and is fixedly connected to the bottom of the test soil box 1. The lifting screw 25 is rotatably and vertically mounted inside the base 21, with its axis extending vertically to convert rotational motion into vertical linear displacement. A limiting protrusion 27 is located on the top of the lifting screw 25, and a corresponding limiting groove is formed at the bottom of the slider adjustment box 31. The limiting protrusion 27 is engaged within the limiting groove to achieve force transmission between the lifting screw 25 and the slider adjustment box 31. The lifting servo motor 24 is mounted on the lower part of the base 21, and its drive end is connected to the lifting screw 25 via a coupling 37. The transparent telescopic tube cover 26 is a sleeve-type protective structure, fitted around the outer periphery of the lifting screw 25, and extends and retracts synchronously with the vertical movement of the slider adjustment box 31.

[0049] After the lifting servo motor 24 starts, it outputs rotational power, which is transmitted to the lifting screw 25 through the coupling 37, causing the lifting screw 25 to rotate. Under the force transmission action of the limiting protrusion 27 and the limiting groove, the rotation of the lifting screw 25 can be converted into the linear movement of the slider adjustment box 31 in the vertical direction, thereby driving the horizontal position drive component, the locking component and the test tube 4 to rise and fall synchronously, so as to realize the vertical position adjustment of the test tube 4 relative to the short tube 5.

[0050] The transparent telescopic tube cover 26 can provide peripheral protection for the lifting screw 25 during the lifting and adjustment process, so as to reduce the possibility of soil particles, seepage water and other impurities entering the thread gap of the lifting screw 25.

[0051] In one embodiment, the base 21 includes an upper rectangular frame, a lower rectangular frame, and a hollow cylindrical column connected between the upper and lower rectangular frames. The lifting screw 25 is rotatably disposed inside the hollow cylindrical column. There are two lifting components, and an adjustable toothed connector 22 is disposed between the bases 21 of the two lifting components.

[0052] Each base 21 can adopt a one-piece steel support structure, consisting of an upper rectangular frame, a lower rectangular frame, and a hollow cylindrical column positioned between them. The lower rectangular frame is fixed to the bottom of the test soil tank 1 to provide an installation foundation; the hollow cylindrical column is vertically positioned between the upper and lower rectangular frames, forming a space inside for the lifting screw 25 to pass through, thus providing guidance for the lifting screw 25; the upper rectangular frame is located at the top of the hollow cylindrical column to provide connection support for the transparent telescopic tube cover 26 and the slider adjustment box 31. Anchor bolt holes 23 can be provided on the lower rectangular frame to connect it to the bottom plate of the test soil tank 1 via the anchor bolts 23.

[0053] Two lifting components are symmetrically arranged on the bottom plate of the test soil box 1 below the test tube 4 along the axial direction of the test tube 4 to form a double-point support structure for the test tube 4. An adjustable toothed connector 22 is provided between the bases 21 of the two lifting components. The adjustable toothed connector 22 can adjust the span between the two lifting components by adjusting the meshing position to adapt to test tubes 4 with different diameters, lengths or support spacing requirements.

[0054] In one embodiment, two overflow perforated plates 14 are provided, and the two overflow perforated plates 14 are respectively arranged on opposite sides of the test soil box 1, forming two independent water tanks within the test soil box 1; the buried drainage pipe seepage test device simulating adjustable interface defects also includes a water supply tank assembly 7, which includes a water tank 71, a circulating water pump 72, a water supply pipe 73, a control valve 74, a water level balancing pipe 75, and two level gauges 9. The circulating water pump 72 is arranged inside the water tank 71, and the water supply pipe 73 connects the circulating water pump 72 to the independent water tanks; the control valve 74 is connected to the water supply pipe 73; the water level balancing pipe 75 is connected to the same height of the two independent water tanks; and the two level gauges 9 are respectively arranged in the two independent water tanks.

[0055] Two overflow perforated plates 14 are vertically arranged parallel to each other on opposite sides inside the test soil box 1, and each maintains a preset distance from the side plate of the test soil box 1, thus forming two independent water tanks. The two independent water tanks are distributed on both sides of the test pipe 4, which can provide two-sided seepage conditions to the soil in the test soil box 1.

[0056] The water supply tank assembly 7 provides controllable water supply and water level regulation for two independent water tanks. A circulating water pump 72 is installed inside the water tank 71 to provide water delivery power; a water supply pipe 73 connects the circulating water pump 72 to the two independent water tanks; a control valve 74 is installed on the water supply pipe 73 to regulate the water inlet and flow rate of the corresponding water tank; a water level balancing pipe 75 connects to the same height in both independent water tanks to form a communicating vessel structure between them, thus facilitating automatic water level balancing; two level gauges 9 are installed in the two independent water tanks respectively to monitor water level changes.

[0057] Before the test, a predetermined amount of test water can be injected into the water tank 71. After starting the circulating water pump 72, the opening of the control valve 74 is adjusted according to the test conditions to transport the water to two independent water tanks via the water supply pipe 73. With the help of the water level balancing pipe 75, the water levels in the two independent water tanks can be kept consistent. The level gauge 9 is used to monitor water level changes so that the valve can be adjusted according to the monitored value, thereby forming a relatively stable hydraulic boundary condition.

[0058] In one embodiment, the buried drainage pipe seepage test device simulating adjustable interface defects further includes a water and sand collection tank 6, a filter baffle 61, an electronic scale 62, a pressure level sensor 63, and a camera 8. The water and sand collection tank 6 is located at the outlet end of the short pipe 5; the filter baffle 61 is located inside the water and sand collection tank 6; the electronic scale 62 is located at the bottom of the water and sand collection tank 6; the pressure level sensor 63 is located on the bottom side inside the water and sand collection tank 6; and the camera 8 is located on one side of the water and sand collection tank 6.

[0059] A water-sand collection box 6 is located below the outlet end of the short pipe 5 outside the test soil box 1, and is used to collect the water-sand mixture that leaks out from the interface defect during the test. A filter baffle 61 is detachably installed inside the water-sand collection box 6. The filter baffle 61 has several water-permeable holes to form a water-sand separation structure, thereby allowing seepage water to pass through and initially intercepting particles. An electronic scale 62 is used to continuously record the total weight of the mixture in the water-sand collection box 6, and a pressure-type liquid level sensor 63 is used to measure the corresponding liquid level or hydrostatic pressure of the water in the box in order to convert the water volume. The camera 8 can cover the transparent plate 12 of the test soil box 1 and the interface area of ​​the short pipe 5, and is used to record the changes in the soil around the pipe and near the interface.

[0060] During the experiment, the water-sand mixture flowing out from the interface defect can flow out along the short pipe 5 and flow into the water-sand collection box 6. After passing through the filter plate 61, the water and sand can be initially separated; the electronic scale 62 and the pressure liquid level sensor 63 can collect relevant weight and liquid level data respectively to provide a data basis for seepage flow, loss of particle mass and related analysis; the camera 8 can simultaneously record visual image information during the experiment.

[0061] In one embodiment, the buried drainage pipe seepage test device for simulating adjustable interface defects further includes a curved guide slope plate 19, which is fixed on the test soil box 1 and located below the end of the short pipe 5 located outside the test soil box 1; the curved guide slope plate 19 is an arc-shaped plate with its arc surface facing the water and sand collection box 6.

[0062] In this embodiment, the curved guide slope 19 is disposed in front of the transparent variable diameter disc 16 to guide the flow direction of the water-sand mixture caused by leakage at the interface defect. The curved guide slope 19 is a downwardly curved arc plate with its arc surface facing the water-sand collection box 6, so that the water-sand mixture can be collected downward and introduced into the water-sand collection box 6.

[0063] In one embodiment, the short tube 5 has an annular groove 51 at one end near the interface. During testing, workers can use a special tool to insert into the annular groove 51 and slightly pull out or push back the short tube 5 axially to simulate defects such as interface disconnection.

[0064] Secondly, this embodiment also provides a method for testing the seepage of buried drainage pipes, including the following steps: Prepare test soil box 1, and install overflow perforated plates 14 on opposite sides of test soil box 1; A frame-type pipe support assembly 2 is arranged at the bottom of the test soil box 1; A short pipe 5 is installed and fixed through the transparent plate 12 of the test soil box 1. A test pipe 4 is installed and fixed through the side plate of the test soil box 1 that is opposite to the transparent plate 12. The test pipe 4 is fixed on the frame-type pipe support assembly 2 and the two pipe interfaces are made to fit together. Soil was filled inside test soil box 1, and sensors were installed; The pipe foundation and cover soil were filled in layers according to the "rainfall method". After each layer reached the specified thickness, it was compacted and roughened appropriately. A thin layer of red sand was laid every 10 cm. According to the test layout, soil pressure gauges, pore water pressure gauges, displacement gauges and other sensors were buried at different depths and the spatial coordinates were recorded. At the same time, the support monitoring nodes were used to check and correct the slight drift of the support during the filling and soaking stages to ensure that the benchmark for quantifying interface defects was consistent.

[0065] Fill the individual water tank with water; Position the water and sand collection box 6 below the curved slope slab and calibrate its position; connect the water supply tank 71, inlet and outlet pipes and data acquisition system, and connect the signals from the level gauge 9, earth pressure gauge, pore water pressure gauge and camera to the control console and complete zero-point calibration and self-test; then slowly inject water into the water tanks on both sides, so that the water seeps into the soil through the perforated plate, gradually wetting and settling under small hydraulic gradient conditions until the soil is basically saturated and the water level is stable.

[0066] Defects of at least the form of vertical misalignment, vertical undulation, or axial disconnection are applied to the interface between the test pipe 4 and the short pipe 5 by the frame-type pipe support assembly 2, and the corresponding displacement or misalignment is recorded. Under saturated and stable conditions, different forms of defects, such as vertical misalignment, vertical undulation, or axial dislocation, are applied to the interface according to predetermined working conditions through the lifting and lateral position driving components of the frame-type pipe support assembly 2, and the corresponding displacement or misalignment is recorded. In some embodiments, defect quantification and classification can be determined with reference to the "Technical Specification for Inspection and Evaluation of Urban Drainage Pipelines" (CJJ181-2012), and the defect settings are shown in Table 1. Subsequently, a formal seepage test is carried out under the target head difference. A constant water level difference is maintained by continuously replenishing water in the water tank. At the same time, the weighing and liquid level sensors in the water and sand collection tank 6 acquire the seepage flow rate, mixture weight, and sand content in real time, and simultaneously collect multi-source data such as soil pressure, pore water pressure, and pipe deformation.

[0067] Table 1 Defect Settings:

[0068] Collect the water and solid particles flowing out of short pipe 5. After completing each working condition, gradually lower the water level and shut off the water supply system. Remove the water and sand collection box 6 and weigh, dry and classify the water and solid particles in it. Then, excavate the soil layer by layer from top to bottom, remove the pipes, supports and perforated plates in sequence, clean and dry the box and components, and restore the initial working conditions for the next set of tests.

[0069] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A test device for simulating seepage in buried drainage pipes with adjustable interface defects, characterized in that, include: The test soil box (1) has at least one side panel as a transparent panel (12); A short tube (5) passes through the transparent plate (12) and is fixed to the transparent plate (12); The test tube (4) is fixed through the side plate of the test soil box (1) opposite to the transparent plate (12). The end of the test tube (4) inside the test soil box (1) is opposite to the end of the short pipe (5) inside the test soil box (1) to form a pipe interface to simulate the defect. A frame-type pipe support assembly (2) is set inside the test soil box (1) and connected to the test pipe (4). The frame-type pipe support assembly (2) includes a lifting component and a locking component connected to the lifting component. The locking component is fixedly connected to the test pipe (4). The lifting component is used to drive one end of the test pipe (4) located inside the test soil box (1) to move in the height direction relative to one end of the short pipe (5) located inside the test soil box (1) to simulate the vertical defects of the pipe interface. At least one overflow perforated plate (14) is placed inside the test soil box (1). An independent water tank is formed between the overflow perforated plate (14) and one side plate of the test soil box (1). The overflow perforated plate (14) is provided with several overflow holes so that the water in the independent water tank can seep into the soil in the test soil box (1) through the overflow holes, thereby forming the hydraulic boundary of the seepage test.

2. The buried drainage pipeline seepage test device for simulating adjustable interface defects according to claim 1, characterized in that, The elevation of the mounting hole on the transparent plate (12) on which the short pipe (5) is installed is lower than the elevation of the mounting hole on the side plate on which the test pipe (4) is installed, so that the short pipe (5) and the test pipe (4) form a unidirectional slope towards the short pipe (5) in the test soil box (1).

3. The buried drainage pipeline seepage test device for simulating adjustable interface defects according to claim 2, characterized in that, Also includes: A transparent variable diameter disc (16) is installed in the mounting hole on the transparent plate (12); The second variable diameter disc (17) is installed in the mounting hole on the side plate; Both the transparent reducing plate (16) and the second reducing plate (17) include an outer circular outer flange and an inner stepped flange. The outer circular outer flange is fixedly connected to the transparent plate (12) or the side plate. The thickness and outer diameter of the inner stepped flange are respectively adapted to the thickness and diameter of the corresponding mounting hole.

4. The buried drainage pipeline seepage test device for simulating adjustable interface defects according to claim 1, characterized in that, The frame-type pipe support assembly (2) also includes a lateral position drive component disposed between the lifting component and the locking component. The lateral position drive component is used to drive one end of the test pipe (4) inside the test soil box (1) to approach or move away from one end of the short pipe (5) inside the test soil box (1) to simulate the horizontal displacement defect of the pipe interface.

5. The buried drainage pipeline seepage test device for simulating adjustable interface defects according to claim 4, characterized in that, The lateral position drive includes: The slider adjustment box (31) is fixedly connected to the lifting component; The offset adjustment servo motor (36) is fixed inside the slider adjustment box (31); The offset lead screw (38) is rotatably disposed in the slider adjustment box (31), one end of which is connected to the drive end of the offset adjustment servo motor (36) through a bearing connector, and the other end is rotatably connected to the inner wall of the slider adjustment box (31). A pair of slide rails (39) are fixed inside the slider adjustment box (31) and are arranged parallel to the offset screw (38); The slider adjustment box (31) has a rectangular through hole on the side facing the locking member, and the locking member is connected to the offset screw (38) and the slide rail (39) through the rectangular through hole.

6. The buried drainage pipeline seepage test device for simulating adjustable interface defects according to claim 5, characterized in that, The locking element includes: The support fixing arm (32) has a threaded rectangular member (35) at its lower part, and the threaded rectangular member (35) is threadedly engaged with the offset screw (38); The pipe clamp half ring (33) is connected to the other end of the support fixing arm (32); The binding strap (34) has its two ends connected to the two ends of the tube clamp half ring (33); The tube clamp half-ring (33) and the binding strap (34) form a closed ring to fix the test tube (4).

7. The buried drainage pipeline seepage test device for simulating adjustable interface defects according to claim 5, characterized in that, The lifting component includes: The base (21) is fixed to the bottom of the test soil box (1); The lifting screw (25) is rotatably mounted inside the base (21); A limiting protrusion (27) is provided on the top of the lifting screw (25), and a limiting groove is provided at the bottom of the slider adjustment box (31). The limiting protrusion (27) is limited to the limiting groove. The lifting servo motor (24) is driven by the lifting screw (25) via a coupling (37); A transparent telescopic tube cover (26) is fitted around the outer periphery of the lifting screw (25), and its upper and lower ends are fixedly connected to the base (21) and the slider adjustment box (31) respectively.

8. The buried drainage pipeline seepage test device for simulating adjustable interface defects according to claim 7, characterized in that, The base (21) includes an upper rectangular frame, a lower rectangular frame, and a hollow cylindrical column connected between the upper rectangular frame and the lower rectangular frame. The lifting screw (25) is rotatably disposed inside the hollow cylindrical column. Two lifting components are provided, and an adjustable toothed connector (22) is provided between the bases (21) of the two lifting components.

9. The buried drainage pipeline seepage test device for simulating adjustable interface defects according to any one of claims 1 to 8, characterized in that, Two overflow perforated plates (14) are provided, and the two overflow perforated plates (14) are respectively arranged on opposite sides of the test soil box (1), and the test soil box (1) is divided into two independent water tanks; The test apparatus further includes a water supply tank assembly (7), which comprises: Water tank (71); A circulating water pump (72) is installed inside the water tank (71); A water supply pipe (73) connects the circulating water pump (72) to the independent water tank; A control valve (74) is connected to the water supply pipe (73); A water level balancing pipe (75) is connected to the two independent water tanks at the same height; Two level gauges (9) are respectively installed in the two independent water tanks.

10. The buried drainage pipeline seepage test device for simulating adjustable interface defects according to any one of claims 1 to 8, characterized in that, Also includes: A water and sand collection box (6) is installed at the outlet end of the short pipe (5); A filter baffle (61) is installed inside the water and sand collection box (6); An electronic scale (62) is installed at the bottom of the water and sand collection box (6); A pressure-type liquid level sensor (63) is installed on the bottom side inside the water and sand collection tank (6); A camera (8) is installed on one side of the water and sand collection box (6).

11. The buried drainage pipeline seepage test device for simulating adjustable interface defects according to claim 10, characterized in that, It also includes a curved guide slope plate (19), which is fixed on the test soil box (1) and located below the end of the short pipe (5) located outside the test soil box (1); The curved guide slope plate (19) is an arc-shaped plate with its arc surface facing the water and sand collection box (6).

12. A method for simulating seepage in buried drainage pipes based on adjustable interface defects, characterized in that, Includes the following steps: A buried drainage pipeline seepage test device for simulating adjustable interface defects as described in any one of claims 1 to 11 is provided, wherein a transparent plate (12), an overflow perforated plate (14), and a transparent variable diameter plate (16) and a second variable diameter plate (17) matching the pipe diameter are installed on the test soil box (1). A frame-type pipe support assembly (2) is arranged at the bottom of the test soil box (1). The test pipe (4) and the short pipe (5) are installed on opposite sides of the test soil box (1) respectively. The position of the test pipe (4) is adjusted so that the interface of the test pipe (4) and the short pipe (5) fits together. Soil was filled into the test soil box (1), and sensors were installed according to the test requirements; Water is supplied to the independent water tank, allowing the water to seep into the soil through the overflow perforated plate (14) until the soil reaches the predetermined saturated and stable state. Under the predetermined saturated stable state, a predetermined defect is applied to the interface between the test pipe (4) and the short pipe (5) through the frame-type pipe support assembly (2) to form at least one of the following working conditions: vertical misalignment, vertical undulation, horizontal misalignment, compound misalignment, or axial disconnection. Seepage test is carried out under the target head difference condition, and the corresponding seepage flow rate, sand transport rate, and test image data are collected. After completing the tests under various working conditions, the water level was lowered and the water supply was stopped. The outflowing water and solid particles were collected and analyzed, and the soil in the test soil box (1) was excavated in layers.

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