Physical model test device and method for piping failure process of dike engineering

Abstract

The invention relates to a physical model test device and method for the piping failure process of an embankment project, and the method comprises the following steps: filling a sample in a sample filling chamber in a layered manner, arranging a pore water pressure sensor and a soil pressure box, and reserving a leakage channel in a downstream soil body of the sample filling chamber; the self-circulation intelligent water head adjusting system simulates water level change through a water level adjusting plate and a submersible pump, and a pore water pressure sensor and a soil pressure box record pore water pressure and soil stress data in real time until piping damage occurs to a sample. The device has the advantages that the water level adjusting plate and the submersible pump are controlled through the intelligent water level adjusting system, the water level adjusting plate provides periodical change for the water level, the submersible pump further accurately adjusts the water level, seepage fields of dike projects under various complex water level working conditions in actual projects can be simulated and researched, and the dike project seepage field simulation effect is improved. The piping failure process under different water head conditions is simulated more truly, and the mechanism of formation and development of the piping failure process is explored.

Description

Technical Field

[0001] The invention belongs to the field of physical model tests for water conservancy projects, and in particular relates to a physical model test device and method for a pipe burst failure process in a levee project. Background Art

[0002] Levee projects are one of the key infrastructures for flood control and disaster relief. Their safety is directly related to the safety of life and property of people in riverside protection areas. However, during the long-term operation of the levees, they often face the risk of instability due to the long-term action of infiltration water flow, especially pipe bursts, which are often sudden and severe in their destructiveness.

[0003] Piping is one of the most destructive forms of seepage failure. It is caused by the seepage pressure caused by the water level difference inside and outside the levee. When the seepage pressure exceeds the shear strength of the soil, the water flow begins to erode the fine-grained soil in the levee, gradually forming seepage channels or underground cavities. This phenomenon is particularly common in sandy soils or other soils with high permeability. Once formed, it may expand rapidly, reducing the strength and stability of the soil, leading to a large amount of soil loss, and ultimately causing the overall instability of the levee or even collapse.

[0004] In recent years, with the frequent occurrence of extreme weather events caused by climate change, the scale and frequency of floods have increased, making the problem of piping more serious. Especially in areas prone to floods, levees are under the influence of high water levels for a long time, and seepage and infiltration phenomena occur frequently, which seriously threatens the structural stability of the levees. In order to deeply understand the formation mechanism of piping and its impact on the safety of levees, it is very important to conduct refined piping test research. In the prior art, the research on piping damage mostly adopts a method combining numerical simulation and field tests. However, numerical simulation is limited by the assumptions of the model and cannot fully reflect the piping damage process in actual projects under complex water heads; and field tests are subject to restrictions such as high cost, long cycle and complex operation, and are difficult to be widely used in daily research and design. In addition, existing studies mostly use test devices under simplified conditions to understand the destruction process of piping by indirect detection, which is difficult to simulate the real situation under complex water heads.

[0005] Therefore, there is an urgent need for a physical model test device and method that can simulate the piping failure process under complex water heads to make up for the shortcomings of the existing technology, which is of great significance to the design and maintenance of embankment projects. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a physical model test device and method for the pipe burst failure process of a levee project.

[0007] The physical model test device for the pipe burst failure process of the levee project includes a water storage chamber, a sample filling chamber, an overflow chamber and a self-circulating intelligent water head regulating system, wherein the water storage chamber and the overflow chamber are respectively arranged on both sides of the sample filling chamber;

[0008] A concave impermeable plate is provided between the water storage chamber and the filling chamber. The self-circulating intelligent water head regulating system includes a water level regulating plate and a submersible pump. The water level regulating plate moves up and down on one side of the concave impermeable plate to adjust the height of the lowest depression of the concave impermeable plate.

[0009] The submersible pump is arranged at the bottom of the water storage chamber, the water outlet of the submersible pump is arranged above the upstream of the sample filling chamber, and an ultrasonic water level sensor is arranged above the upstream of the sample filling chamber.

[0010] Preferably, pore water pressure sensors and soil pressure cells are layered in the sample in the sample filling chamber.

[0011] Preferably, the water storage chamber and the overflow chamber are connected via a return pipe, a filter box is provided on the top of the overflow chamber, and the top of the filter box is flush with the top of the sample in the sample filling chamber.

[0012] Preferably, the water level regulating plate is arranged on the side of the concave waterproof plate facing the water storage chamber, and transmission mechanisms are symmetrically connected on both sides of the water level regulating plate. The two transmission mechanisms are respectively installed on both sides of the concave waterproof plate.

[0013] The method for using the physical model test device for the pipe burst failure process of a dike project comprises the following steps:

[0014] Step 1: Fill the sample in layers in the sample filling chamber and arrange the pore water pressure sensor and soil pressure box, and reserve a leakage channel in the soil body downstream of the sample filling chamber;

[0015] Step 2: Add water to the sample filling chamber through the self-circulating intelligent water head adjustment system until the sample is saturated;

[0016] Step 3: The self-circulating intelligent water head regulation system simulates the water level change through the water level regulating plate and the submersible pump, and the pore water pressure sensor and the soil pressure box record the pore water pressure and soil stress data in real time until the sample is damaged by piping;

[0017] Step 4: Repeat the above steps and conduct multiple groups of model tests by changing the position and size of the leakage channel.

[0018] Preferably, in step three, the self-circulating intelligent water head regulating system simulates the periodic change of water head by moving the water level regulating plate, and simultaneously discharges water to the sample filling chamber through a submersible pump to achieve accurate compensation of water level changes.

[0019] The beneficial effects of the present invention are:

[0020] 1) The present invention controls the water level regulating plate and the submersible pump through an intelligent water level regulating system. The water level regulating plate provides periodic changes for the water level, and the submersible pump makes further precise adjustments to the water level. It can simulate and study the seepage field of levee projects under various complex water level conditions in actual projects, accurately and intuitively reproduce the piping damage of levee projects, greatly reduce the defects of large errors and low precision of piping devices under simplified conditions used in existing studies, solve the technical problems of inaccurate head control and insufficient simulation capability of dynamic head changes in the prior art, more realistically simulate the piping damage process under different head conditions, and explore its formation and development mechanism.

[0021] 2) The present invention simulates different seepage conditions by changing the setting of the reserved leakage channel. The position of the reserved channel from the embankment foot can be adjusted to study the influence of the leakage channel position on the seepage damage; the diameter of the reserved channel can be adjusted to study the influence of the leakage channel size on the seepage damage. It can also simulate the actual piping seepage damage phenomenon of different types of embankment projects by changing the distribution type of foundation samples, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the physical model test device of the present invention;

[0023] Figure 2 It is a schematic diagram of the structure of a water level regulating plate driven by a stepping motor of the present invention;

[0024] Figure 3 is a top view of the arrangement of the reserved holes and pore water pressure sensors of the present invention;

[0025] Figure 4 This is an attempt to install the earth pressure box of the present invention.

[0026] Explanation of the reference numerals: model trough 1, concave waterproof plate 2, rectangular waterproof plate 3, permeable plate 4, pipeline 5, return pipe 6, filter box 7, ultrasonic water level sensor 8, submersible pump 9, stepper motor 10, screw 11, water level adjustment plate 12, slider 13, pore water pressure sensor 14, soil pressure box 15, slot 16, solenoid valve 17. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with embodiments. The description of the following embodiments is only used to help understand the present invention. It should be noted that for ordinary persons in the art, without departing from the principle of the present invention, the present invention can also be modified in some ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0028] Embodiment 1

[0029] As an example, Figures 1 to 4As shown in FIG. 1 , the physical model test device for the pipe burst failure process of the levee engineering includes a transparent model tank 1, a self-circulating intelligent water head regulation system and a data acquisition system. The model tank 1 includes a water storage chamber, a sample filling chamber, an overflow chamber and a self-circulating intelligent water head regulation system. Figure 1 As shown, the water storage chamber and the overflow chamber are respectively arranged on the left and right sides of the sample filling chamber.

[0030] The water storage chamber is located on the left side of the model tank 1 and is used to store and replenish the water required for the test; the sample filling chamber is located in the middle and is used to fill the test samples from bottom to top. Figure 3 and Figure 4 As shown, pore water pressure sensors 14 and soil pressure boxes 15 are arranged equidistantly from top to bottom in the sample, which are used to monitor the pore water pressure and soil stress in the sample in real time, respectively; the overflow chamber is located on the right side, which is used to collect and circulate the seepage water generated during the test, and a return pipe 6 is opened at the bottom of the overflow chamber to connect with the water storage chamber.

[0031] The water storage chamber, the filling chamber and the overflow chamber are separated by two baffles. When the water level in the water storage chamber is higher than the height of the baffle, water flows from the water storage chamber to the filling chamber.

[0032] The submersible pump control system includes a submersible pump 9, a solenoid valve 17, a pipeline 5 and an ultrasonic water level sensor 8. The submersible pump 9 is installed at the bottom of the water storage chamber, the submersible pump 9 is arranged at the bottom of the water storage chamber, the water outlet of the submersible pump 9 is arranged above the upstream of the sample filling chamber, and the ultrasonic water level sensor 8 is arranged above the upstream of the sample filling chamber.

[0033] The solenoid valve 17 is installed on the pipeline 5 and used in conjunction with the submersible pump 9. The solenoid valve 17 adjusts the opening according to the real-time feedback signal of the ultrasonic water level sensor 8 through the PLC control system, and automatically adjusts the water flow rate of the submersible pump 9 to ensure that the amount of water entering the filling chamber can be accurately adjusted according to the set water level change conditions. It is used to monitor and adjust the water level at the upstream of the model sample to ensure the water circulation and water level stability during the test. In this way, the solenoid valve 17 can not only control the flow, but also quickly respond to the adjustment needs of the flow to achieve fine control.

[0034] Embodiment 2

[0035] As another embodiment, this embodiment 2 proposes a more specific physical model test device for the pipe burst failure process of a levee project based on the embodiment 1:

[0036] The partition between the water storage chamber and the filling chamber is a concave impermeable plate 2, the baffle separating the filling chamber from the overflow chamber is a rectangular impermeable plate 3, and a filter box 7 covered with a filter net is arranged on the side of the rectangular impermeable plate 3 facing the overflow chamber as a seepage escape particle collection box for filtering and collecting solid particles in the test tail water. The filter box 7 is arranged on the top of the overflow chamber, and the top of the filter box 7 is flush with the top of the sample in the sample filling chamber.

[0037] The self-circulating intelligent water head regulating system includes a water level regulating plate 12 and a submersible pump 9. The water level regulating plate 12 moves up and down on one side of the concave waterproof plate 2 to adjust the height of the lowest point of the concave waterproof plate 2, and is used to adjust the flow rate of water entering the sample filling chamber and change the amount of water entering.

[0038] like Figure 2 As shown, the water level regulating plate 12 is arranged on the side of the concave waterproof plate 2 facing the water storage chamber, and the two sides of the water level regulating plate 12 are symmetrically connected with transmission mechanisms, and the two transmission mechanisms are respectively installed on the two sides of the concave part of the concave waterproof plate 2. The transmission mechanism is specifically a precision screw transmission mechanism driven by a stepping motor, including a stepping motor 10, a screw 11 and a slider 13. The stepping motor 10 drives the screw 11 to rotate, so that the slider 13 moves up and down along the screw 11. The slider 13 is fixedly connected to the side of the water level regulating plate 12 to accurately adjust the height of the water level plate 12.

[0039] It should be noted that the parts in this embodiment that are the same or similar to those in the first embodiment can be referenced to each other and will not be described in detail in this application.

[0040] Embodiment 3

[0041] As another embodiment, this embodiment 3, based on the first and second embodiments, proposes a method for using the physical model test device for the pipe burst failure process of the dike project:

[0042] Step 1: According to the experimental design, select the samples required for the filling physical model, symmetrically and staggeredly fill the samples in layers in the sample filling chamber with high uniformity along both sides of the central axis of the sample filling chamber, and arrange pore water pressure sensors 14 and soil pressure cells 15, and reserve a leakage channel in the soil body downstream of the sample filling chamber;

[0043] Step 2: Add water to the sample filling chamber through the self-circulating intelligent water head adjustment system until the sample is saturated and the air in the sample is completely removed;

[0044] Step three, the self-circulating intelligent water head regulating system simulates the water level change through the water level regulating plate 12 and the submersible pump 9, wherein the self-circulating intelligent water head regulating system simulates the periodic change of the water head through the movement of the water level regulating plate 12, and when simulating the preset water head change conditions, such as constant water head, sine wave, step wave, etc., the PLC system accurately controls the motion trajectory of the stepper motor 10 according to the preset water level change function, so that the water level regulating plate 12 rises and falls according to the set rules.

[0045] The PLC monitors the operating status of the submersible pump 9 and the solenoid valve 17, and discharges water to the sample filling chamber through the submersible pump 9. By adjusting the basic flow of the submersible pump 9 and the opening of the solenoid valve 17, the water flow entering the sample filling chamber is accurately controllable, and the constant or dynamic change of the water level upstream of the filling chamber is achieved, so as to achieve the purpose of accurately controlling the water flow and water level entering the sample filling chamber and simulating different head conditions.

[0046] The pore water pressure sensor 14 and the soil pressure box 15 record the pore water pressure and soil stress data in real time. The data acquisition system is connected in sequence by the pore water pressure sensor 14, the soil pressure box 15, the resistance strain gauge, the data acquisition analyzer, and the computer terminal, and is used to collect and record the pore water pressure and soil pressure data of each monitoring point in the sample filling room in real time. All sensor data are summarized and transmitted to the computer terminal through the data acquisition instrument to analyze the piping failure process under different water head conditions until piping failure occurs to the sample.

[0047] Step 4: Repeat the above steps and conduct multiple groups of model tests by changing the position and size of the leakage channel.

[0048] It should be noted that the parts in this embodiment that are the same or similar to those in Embodiments 1 and 2 can be referenced to each other and will not be described in detail in this application.

[0049] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

Claims

1. A physical model test device for the pipe burst failure process of a dike project, characterized in that: It includes a water storage chamber, a sample filling chamber, an overflow chamber and a self-circulating intelligent water head adjustment system. The water storage chamber and the overflow chamber are respectively arranged on both sides of the sample filling chamber; A concave impermeable plate is provided between the water storage chamber and the filling chamber. The self-circulating intelligent water head regulating system includes a water level regulating plate and a submersible pump. The water level regulating plate moves up and down on one side of the concave impermeable plate to adjust the height of the lowest depression of the concave impermeable plate. The submersible pump is arranged at the bottom of the water storage chamber, the water outlet of the submersible pump is arranged above the upstream of the sample filling chamber, and an ultrasonic water level sensor is arranged above the upstream of the sample filling chamber.

2. The physical model test device for the pipe burst failure process of levee engineering according to claim 1 is characterized in that: Pore ​​water pressure sensors and soil pressure cells are installed in each layer of the sample in the sample filling chamber.

3. The physical model test device for the pipe burst failure process of embankment engineering according to claim 1 is characterized in that: The water storage chamber and the overflow chamber are connected through a return pipe. A filter box is arranged on the top of the overflow chamber, and the top of the filter box is flush with the top of the sample in the sample filling chamber.

4. The physical model test device for the pipe burst failure process of embankment engineering according to claim 1 is characterized in that: The water level regulating plate is arranged on the side of the concave waterproof plate facing the water storage chamber, and transmission mechanisms are symmetrically connected on both sides of the water level regulating plate. The two transmission mechanisms are respectively installed on both sides of the concave part of the concave waterproof plate.

5. A method for using the physical model test device for the pipe burst failure process of a dike project as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: Fill the sample in layers in the sample filling chamber and arrange the pore water pressure sensor and soil pressure box, and reserve a leakage channel in the soil body downstream of the sample filling chamber; Step 2: Add water to the sample filling chamber through the self-circulating intelligent water head adjustment system until the sample is saturated; Step 3: The self-circulating intelligent water head regulation system simulates the water level change through the water level regulating plate and the submersible pump, and the pore water pressure sensor and the soil pressure box record the pore water pressure and soil stress data in real time until the sample is damaged by piping; Step 4: Repeat the above steps and conduct multiple groups of model tests by changing the position and size of the leakage channel.

6. The method for using the physical model test device for the pipe burst failure process of a dike project according to claim 5 is characterized in that: In step three, the self-circulating intelligent water head regulation system simulates the periodic change of water head by moving the water level regulating plate, and at the same time discharges water into the sample filling chamber through the submersible pump to achieve accurate compensation of water level changes.

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