Device and method for simulating soil erosion during seawall overtopping

Abstract

The invention provides a device for simulating soil erosion during seawall overtopping and a simulation method. A water flow passage is defined by the inner wall surface of a test pipeline, and a test piece inlet is communicated with the water flow passage; the water outlet end of the water supply device communicates with the upstream of the water flow channel. The test piece jacking device comprises a jacking mechanism, a detection piece and a control module, a test piece mounting position on the jacking mechanism is embedded in a guide cylinder connected with the test piece inlet, a test piece extends into water flow of the water flow passage along with movement of the test piece mounting position, and the distance from the top of the test piece to the bottom of the water flow passage is the upper limit height; the detection piece detects the height of the test piece in the water flow channel; the control module is used for controlling the jacking mechanism to drive the test piece mounting position to ascend when the detection piece detects that the height of the test piece reaching the bottom of the water flow passage reaches the lower limit height, so that the distance from the top of the test piece to the bottom of the water flow passage reaches the upper limit height again, soil body erosion during seawall overtopping is simulated, and soil body erosion characteristics are researched.

Description

Technical Field

[0001] The invention relates to the technical field of seawall engineering, and in particular to a device and a simulation method for simulating soil erosion when seawalls are overtopping waves. Background Art

[0002] Seawall engineering is an important infrastructure project in estuary and coastal areas for defending against marine disasters such as storm surges. However, under the action of extreme ocean dynamics, seawall overtopping often occurs. The overtopping water flow will have a serious impact and damage on the seawall, especially the back slope, causing erosion and collapse of the back slope of the seawall. In severe cases, it will lead to the overall destruction of the seawall. Therefore, the study of the erosion characteristics of the back slope of the seawall under overtopping is of great significance to my country's coastal disaster prevention projects. The erosion characteristics of the soil on the back slope of the seawall are the basis for studying the failure mechanism of soil seawalls. At present, the method for studying the erosion characteristics of the existing back slope is generally to conduct experiments through seawall models, but model experiments often require a lot of manpower and material resources, and cannot efficiently study the erosion characteristics of the seawall soil.

[0003] Therefore, there is an urgent need to propose a set of devices that can effectively simulate the process of soil erosion when the seawall is overtopping the waves and conduct research on the erosion characteristics of the seawall soil. Summary of the invention

[0004] The purpose of the present invention is to provide a device and a simulation method for simulating soil erosion when a seawall is overrun by waves, so as to solve the problems existing in the above-mentioned prior art. A jacking mechanism drives a test piece located in a test piece installation position to move upward, so that the test piece extends into a water flow path, until the top of the test piece reaches or exceeds an upper limit height; the test piece located in the water flow path is eroded; a detection piece monitors the height difference between the test piece and the inner surface of a test pipe in real time. If the test piece is lower than or reaches the lower limit height, the jacking mechanism controls the test piece to rise, so that the test piece can pass into the water flow path again, and the time of each jacking of the test piece is recorded and transmitted to a computer data processing system. This can simulate the process of soil erosion when a seawall is overrun by waves, and realize the study of the erosion characteristics of seawall soil.

[0005] To achieve the above-mentioned purpose, the present invention provides the following scheme: a device for simulating soil erosion when a seawall is overrun by waves is provided, comprising: a test pipe, the inner wall surface of the test pipe enclosing a water flow passage, a test piece inlet connected to the water flow passage is provided at the bottom of the test pipe; a water supply device, the water outlet end of the water supply device is connected to the upstream of the water flow passage; a test piece lifting device, comprising a lifting mechanism for delivering the test piece into the water flow passage, a detection member and a control module; a test piece installation position for installing the test piece is provided on the lifting mechanism, the test piece installation position is embedded in a guide cylinder connected to the test piece inlet, the test piece extends into the water flow of the water flow passage as the test piece installation position moves, and the test piece The distance that the top is higher than the bottom of the water flow passage is the upper limit height; the test pipeline is also provided with an electric regulating valve for controlling the flow rate of the water flow passage, and the electric regulating valve is located downstream of the test piece inlet; the detection piece is used to detect the height of the test piece located in the water flow passage; the detection piece and the lifting mechanism are both electrically connected to the control module, and the control module is used to control the lifting mechanism to drive the test piece installation position to rise when the detection piece detects that the height of the test piece reaching the bottom of the water flow passage reaches the lower limit height, so that the distance that the top of the test piece is higher than the bottom of the water flow passage reaches the upper limit height again, and the detection piece and the lifting mechanism are both electrically connected to the control module. A flow rate regulating device, wherein the flow rate regulating device monitors the flow in the test pipeline in real time through an electromagnetic flowmeter, and can control the flow in the test pipeline in real time through an electric regulating valve, thereby controlling the flow of water in the test pipeline and realizing periodic changes in the water flow rate in the test pipeline; a seepage simulation device; wherein the pressure water tank in the seepage simulation device is connected to the guide cylinder through a hose, so that the water flowing out of the pressure water tank can act on the test piece, and the reciprocating motion of the slide of the second linear guide rail is controlled by programming the single-axis controller to realize the adjustment of the height of the pressure water tank, and apply a constant or variable seepage hydraulic gradient to the test piece; a movable steel frame, wherein the movable steel frame is connected to the first steel frame through a square steel pipe, and the inclination angle of the movable steel frame is adjusted by adjusting the installation position of the square steel pipe on the first steel frame, thereby changing the position of the test pipeline and simulating the inclination angle of the back slope of the seawall.

[0006] Preferably, the water supply device comprises an erosion water tank located above the test pipe, and the erosion water tank is connected to the test pipe through a first hose.

[0007] Preferably, the lifting mechanism includes a linear motor located below the test pipe, the movable end of the linear motor is connected to a lifting piston, the specimen mounting position is arranged on the top surface of the lifting piston, the guide cylinder is fixedly connected to the test pipe, and the lifting piston slides along the inner wall surface of the guide cylinder.

[0008] Preferably, the test pipe is a rectangular pipe, and the guide cylinder is fixed to the lower side of the rectangular pipe; the outer wall of the guide pipe is sleeved with a sealing plate, the sealing plate is sealed and connected to the outer wall of the guide pipe, and the upper surface of the sealing plate is sealed and fits with the lower side of the rectangular pipe.

[0009] Preferably, an electromagnetic flowmeter for detecting the flow rate in the water flow passage is also provided in the water flow passage, and the electromagnetic flowmeter and the electric regulating valve are both connected to the control module.

[0010] Preferably, it also includes an angle adjustment mechanism for adjusting the inclination angle of the test pipe, the angle adjustment mechanism includes a base steel frame, a first steel frame and a movable steel frame; one end of the movable steel frame is hinged to the base steel frame, the first steel frame is provided with a plurality of mounting holes along the height direction, and the other end of the movable steel frame is bolted to the mounting holes on the first steel frame; the test pipe is fixedly connected to the movable steel frame, the erosion water tank is connected to the first steel frame, and the detection component and the lifting mechanism are both arranged on the movable steel frame.

[0011] Preferably, the downstream of the test pipeline is also connected to a first water tank, and the first water tank is connected to the erosion water tank through a first water pump.

[0012] Preferably, it also includes a seepage simulation device, which includes a pressure water tank and a second steel frame, the pressure water tank is slidably connected to the second steel frame, a second water storage tank is connected to the second steel frame, the water inlet end of the pressure water tank is connected to the second water storage tank through a second water pump, and the water outlet end of the pressure water tank is connected to the guide cylinder.

[0013] A simulation method for simulating soil erosion during seawall overtopping, comprising the device for simulating soil erosion during seawall overtopping, and the specific steps further include:

[0014] S1. Place the specimen in the specimen installation position on the lifting mechanism;

[0015] S2, turning on the water supply device, injecting water into the water flow path and closing the electric regulating valve, so that the water flow in the water flow path is stationary for a certain period of time;

[0016] S3. Control the lifting mechanism to move upward, so that the lifting mechanism drives the specimen located at the specimen installation position to move upward, and a part of the main body of the specimen extends into the water flow path in the test pipeline until the top of the specimen reaches the upper limit height or is higher than the upper limit height;

[0017] S4, opening the electric regulating valve, allowing the water flow to erode the test piece in the water flow path; and detecting the height of the test piece in the water flow path in real time by the detection element;

[0018] S5. When the test piece is lower than or reaches the lower limit height, the erosion of the test piece in the water flow passage is completed, the test piece is lower than the inner wall surface of the test pipe, and the lifting mechanism drives the test piece to rise so that the test piece can be passed into the water flow passage again. The time of each lifting of the test piece is recorded and transmitted to the data processing system of the computer;

[0019] S6. The test is terminated after the test piece is lifted a certain number of times.

[0020] Preferably, in step S2, the resting time is 10-15 minutes.

[0021] Compared with the prior art, the present invention has achieved the following technical effects:

[0022] The test piece is installed in the test piece installation position on the jacking mechanism; the jacking mechanism is controlled to move upward, and the jacking mechanism drives the test piece located in the test piece installation position to move upward, so that part of the main body of the test piece extends into the water flow path in the test pipe until the top of the test piece reaches or exceeds the upper limit height; the test piece located in the water flow path is eroded; the height difference between the test piece and the inner surface of the test pipe is monitored in real time by the detection piece, and the height of the test piece in the water flow path is detected; if the test piece is lower than or reaches the lower limit height, the jacking mechanism controls the test piece to rise, so that the test piece can pass into the water flow path again, and the time of each jacking of the test piece is recorded and transmitted to the data processing system of the computer, which can effectively simulate the erosion process of the soil body when the seawall is overwhelmed by waves, and realize the research on the erosion characteristics of the seawall soil body.

[0023] Other technical solutions of the present invention also have the following technical effects:

[0024] The flow rate in the test pipeline is monitored in real time by an electromagnetic flowmeter, and the flow rate in the test pipeline can be controlled in real time by an electric regulating valve. The flow rate of water in the test pipeline is controlled to achieve periodic changes in the water flow velocity in the test pipeline, thereby simulating the impact of periodic changes in the water flow.

[0025] The pressure water tank in the seepage simulation device is connected to the guide cylinder through a hose, so that the water flowing out of the pressure water tank can act on the test piece, and the reciprocating motion of the slide of the second linear guide rail is controlled by programming the single-axis controller to adjust the height of the pressure water tank and apply a constant or variable seepage hydraulic gradient to the test piece.

[0026] The movable steel frame is connected to the first steel frame through a square steel pipe. The inclination angle of the movable steel frame is adjusted by adjusting the installation position of the square steel pipe on the first steel frame. By changing the position of the test pipeline, the inclination angle of the back slope of the seawall can be simulated, that is, the influence of the inclination angle of the back slope of the seawall can be simulated.

[0027] The present invention can simulate the periodic water flow characteristics of overtopping waves, the seepage hydraulic gradient in the backslope soil, and the slope inclination of the backslope soil, thereby ensuring the accuracy of the soil erosion process during the simulation of seawall overtopping waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0029] Figure 1 It is a schematic diagram of the overall device of the present invention;

[0030] Figure 2 It is a schematic diagram of the jacking mechanism of the present invention;

[0031] Figure 3 It is a schematic diagram of the lifting piston of the present invention;

[0032] Figure 4 It is a schematic diagram of the electric regulating valve and the electromagnetic flowmeter of the present invention;

[0033] Figure 5 This is a schematic diagram of the angle adjustment mechanism of the present invention;

[0034] Figure 6 It is a schematic diagram of the seepage simulation device of the present invention;

[0035] Figure 7 for Figure 6 A partial enlarged view of the top of

[0036] Figure 8 for Figure 6 A partial enlarged view of the middle part;

[0037] Fig. 9 for Figure 6 A partial enlarged view of the bottom of

[0038] Fig.10 It is a working principle diagram of the present invention.

[0039] Among them, 1. test pipeline; 2. water supply device; 3. detection part; 4. lifting mechanism; 5. erosion water tank; 6. linear motor; 7. lifting piston; 8. guide cylinder; 9. sealing plate; 10. electric regulating valve; 11. electromagnetic flowmeter; 12. base steel frame; 13. first steel frame; 14. movable steel frame; 15. first hose; 16. square steel pipe; 17. first water storage tank; 18. first water pump; 19. water outlet pipe; 20. second hose; 21. pressure water tank; 22. second water pump; 23. hinged structure; 24. first pulley; 25. second linear guide rail; 26. second steel frame; 27. second water storage tank; 28. capstan; 29. ​​second pulley; 30. first square swivel joint; 31. second square swivel joint. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] Embodiment 1:

[0043] Please refer to Figures 1 to 10As shown, in this embodiment, a device for simulating soil erosion when a seawall is overrun by waves is provided, comprising a test pipe 1, a water supply device 2, a specimen lifting device, a detection device and a control module. The through hole in the test pipe 1 is a water flow path, and the inner wall surface of the test pipe 1 together forms the water flow path, through which water can circulate, and a specimen inlet is provided at the bottom of the test pipe 1, through which a sample can enter the water flow path in the test pipe 1. The water supply device 2 is used to introduce water into the water flow passage in the test pipe 1, and the water outlet of the water supply device 2 is connected to the upstream of the water flow passage; the test piece lifting device 3, the test piece lifting device includes a lifting mechanism 4, a detection member 3 and a control module, the lifting mechanism 4 is provided with a test piece installation position, the test piece installation position is preferably located on the top surface of the lifting mechanism 4, so that the lifting mechanism 4 is connected to the test piece, the test piece installation position is embedded in the guide cylinder 8, the guide cylinder 8 is connected to the test piece through the guide cylinder 8, the movement of the test piece can be guided, so that the test piece can stably pass through the test piece through the test piece through the test piece through the water flow passage, the test piece can pass through the test piece through the test piece through the moving path of the test piece installation position, and then the lifting mechanism 4 can send the test piece through the test piece through the test piece through the test piece into the water flow in the water flow passage. And the top of the test piece needs to be higher than the bottom of the water flow passage as the upper limit height, the detection device includes the detection member 3, and the height difference between the test piece and the bottom of the water flow passage can be detected by the detection member 3, and the height of the test piece located in the water flow passage is detected. The detection piece 3 and the lifting mechanism 4 are electrically connected to the control module, and the time is set at the lower limit height in the water flow channel. The control module is used to control the lifting mechanism 4 to drive the test piece installation position to rise when the detection piece detects that the height of the test piece reaching the bottom of the water flow channel reaches the lower limit height, so that the distance between the top of the test piece and the bottom of the water flow channel reaches the upper limit height again; it also includes a flow rate regulating device, a seepage simulation device and a movable steel frame 14, and the flow rate regulating device includes an electric regulating valve 10 and an electromagnetic flowmeter 11 (which will be discussed in detail below).

[0044] Working principle: install the specimen in the specimen installation position on the jacking mechanism 4; turn on the water supply device 2, and the water supply device 2 injects water into the water flow path so that the water can fill the test pipe 1, and then stand still for a period of time, and the static time is preferably 10-15 minutes; then, control the jacking mechanism 4 to move upward, and the jacking mechanism 4 can drive the specimen located in the specimen installation position to move upward along the inner wall of the guide cylinder 8, so that part of the main body of the specimen extends into the water flow path in the test pipe 1 until the top of the specimen reaches the upper limit height or is higher than the upper limit height; the water flow can erode the part of the specimen located in the water flow path, simulating the erosion of the seawall by waves; the detection piece 3 can detect the height difference between the test specimen and the inner surface of the test pipe 1 in real time, and detect the height of the specimen in the water flow path.

[0045] If the part of the test piece that is higher than the inner wall of the test pipe 1 is fully eroded, that is, the test piece in the water flow path is fully washed away, so that the test piece is lower than or reaches the lower limit height, the lifting mechanism 4 controls the test piece to rise so that the test piece can be passed into the water flow path again, and the time of each lifting of the test piece is recorded and transmitted to the computer data processing system. After the test piece is lifted a certain number of times, the test is automatically terminated. By obtaining the erosion time and erosion height at different erosion rates, the starting shear stress of the soil is obtained by fitting the erosion rate curve, and then the two parameters of erosion coefficient and exponential coefficient are obtained through the shear stress model, so as to realize the study of the erosion characteristics of the seawall soil. Preferably, a cylindrical protective face is taken on the back slope of the seawall as a test piece, and the test piece is the above-mentioned test piece. During the erosion test, the erosion test is performed on the surface of the cylindrical test piece. The flow rate regulating device monitors the flow in the test pipeline 1 in real time through the electromagnetic flowmeter 11, and can control the flow in the test pipeline 1 in real time through the electric regulating valve 10, so as to control the flow of water in the test pipeline 1 and realize periodic changes in the flow rate of water in the test pipeline 1; the pressure water tank 21 in the seepage simulation device is connected to the guide cylinder 8 through a hose, so that the water flowing out of the pressure water tank 21 can act on the test piece, and the reciprocating motion of the slide of the second linear guide rail 25 is controlled by programming the single-axis controller to adjust the height of the pressure water tank 21, so as to apply a constant or variable seepage hydraulic gradient to the test piece; the movable steel frame 14 is connected to the first steel frame 13 through the square steel pipe 16, and the inclination angle of the movable steel frame 14 is adjusted by adjusting the installation position of the square steel pipe 16 on the first steel frame 13, thereby changing the position of the test pipeline 1 and simulating the inclination angle of the back slope of the seawall.

[0046] In one embodiment, the water supply device 2 includes an erosion water tank 5, which is located above the test pipe 1. The erosion water tank 5 and the test pipe 1 have a large height difference. Under the action of the height difference, the gravitational potential energy of the water in the erosion water tank 5 is converted into kinetic energy in the test pipe 1, and a relatively stable flow field is formed in the water flow path in the test pipe 1, that is, the erosion of the test piece is achieved through a stable flow field in the water flow path.

[0047] In one embodiment, the lifting mechanism 4 includes a linear motor 6, which is located below the test pipe 1. The linear motor 6 is preferably a linear rack motor, which can convert electrical energy into mechanical energy of linear motion. The movable end of the linear motor 6 is connected to a lifting piston 7, and the specimen mounting position is set on the top surface of the lifting piston 7. The specimen access port at the bottom of the test pipe 1 is connected with a guide cylinder 8, which is fixedly connected to the test pipe 1, and is vertically arranged and axially aligned with the specimen access port. The guide cylinder 8 is located below the test pipe 1, and preferably the center of the guide cylinder 8 is axially aligned with the rack of the linear rack motor; the lifting piston 7 slides along the inner wall of the guide cylinder 8. Preferably, the surface of the lifting piston 7 is engraved with multiple sealing grooves, preferably two annular grooves, and corresponding rubber sealing rings are placed in the annular grooves, and the lifting piston 7 and the guide cylinder 8 can be sealed by the rubber sealing ring. Driven by the linear motor 6, the lifting piston 7 can slide along the inner wall of the guide cylinder 8, and the test piece on the test piece installation position at the top of the lifting piston 7 can move synchronously. During the test piece lifting process, the height of the test piece is monitored in real time by the detection piece 3.

[0048] In one embodiment, the test pipe 1 is a rectangular pipe, and the length, width and height of the rectangular pipe are preferably 1200×80×60 mm respectively, and it is divided into four sides, upper, lower, left and right, wherein a test piece inlet is provided in the middle of the lower side, and the diameter of the sample inlet is preferably 66 mm; a sealing plate 9 is sleeved on the outer wall surface of the guide cylinder 8, preferably, the sealing plate 9 is fixedly connected to the guide cylinder 8, and the sealing plate 9 is 5 mm away from the top surface of the guide cylinder 8. A through hole is provided in the middle of the sealing plate 9, and the sealing plate 9 can be tightly sleeved on the outer wall surface of the guide cylinder 8 through the through hole. Preferably, the sealing plate 9 is bonded to the outer wall surface of the guide cylinder 8 by glue, and a seal is formed between the sealing plate 9 and the guide cylinder 8, and the upper surface of the sealing plate 9 is closely attached to the lower surface of the rectangular pipe, and a plurality of circular grooves are provided on the upper surface of the sealing plate 9, preferably two circular grooves, and a rubber sealing ring is provided in the circular groove to form a seal between the sealing plate 9 and the rectangular pipe, and preferably, the sealing plate 9 and the rectangular pipe are clamped by a clamp, so as to achieve the fixing and sealing of the guide cylinder 8. Preferably, the guide cylinder 8 is fixedly connected to the rectangular pipe by bolts.

[0049] In one embodiment, an electric regulating valve 10 and an electromagnetic flowmeter 11 are connected to the test pipe 1, and the electric regulating valve 10 and the electromagnetic flowmeter 11 are located at the rear side of the test piece inlet. The flow in the test pipe 1 is monitored in real time by the electromagnetic flowmeter 11, and the flow in the test pipe 1 can be controlled in real time by the electric regulating valve 10. The electric regulating valve 10 and the electromagnetic flowmeter 11 are both electrically connected to the control module; preferably, during operation, the opening and closing degree of the electric regulating valve 10 can be manually adjusted, and the flow in the test pipe 1 can be controlled by reading the value of the electromagnetic flowmeter 11. It is also possible to use software such as GXWorks to compile a program and write it into PLC, and control the opening and closing degree of the electric regulating valve 10 over time through PLC, control the flow of water in the test pipe 1, realize the periodic change of water flow velocity in the test pipe 1, and simulate the influence of periodic change of water flow.

[0050] In one embodiment, the device for simulating soil erosion when the seawall is overrun by waves also includes an angle adjustment mechanism, which includes a base steel frame 12, a first steel frame 13 and a movable steel frame 14; one end of the movable steel frame 14 is connected to the first steel frame 13, and the other end of the movable steel frame 14 is hinged to the base steel frame 12, and a hinge structure 23 is provided at the hinge, and the movable steel frame 14 is connected to the first steel frame 13 by bolts; the first steel frame 13 is vertically arranged, and the first steel frame 13 is provided with a plurality of mounting holes along the height direction, which are also bolt holes, and the plurality of mounting holes are preferably evenly arranged, and the movable steel frame 14 is bolted to the first steel frame 13 through the mounting holes. By adjusting the installation position of the movable steel frame 14 on the first steel frame 13, the movable steel frame 14 is lifted, and the lifting angle of the movable steel frame 14 is determined by the position of the installation hole on the first steel frame 13, so as to adjust the inclination angle of the movable steel frame 14; the main body of the test pipeline 1 is arranged on the top surface of the movable steel frame 14, the test pipeline 1 is fixedly connected to the movable steel frame 14, and the test pipeline 1 can adjust the inclination angle synchronously with the movable steel frame 14; the test pipeline 1 is connected to the water outlet of the erosion water tank 5 through the first hose 15, and the first hose 15 is preferably a steel wire hose. Preferably, when the test pipeline 1 is a rectangular pipeline, the rectangular pipeline is connected to the first hose 15 through the first square to round joint 30. The stability of the connection between the erosion water tank 5 and the test pipeline 1 is ensured by the first hose 15. The erosion water tank 5 is preferably located at the top of the first steel frame 13. The detection member 3 and the lifting mechanism 4 are both arranged on the movable steel frame 14, so that the relative positions between the detection member 3, the lifting mechanism 4 and the test pipeline 1 remain stable. Since the back slope of the seawall has different angles, by adjusting the angle of the movable steel frame 14, the water flow impact angle of the test piece is adjusted in the test pipe 1, so that the inclination angle of the back slope of the seawall can be simulated, that is, the influence of the inclination angle of the back slope of the seawall can be simulated, and the inclination angle of the back slope soil body can be effectively simulated. In addition, the first height adjustment device includes a first linear guide rail, and the first linear guide rail is vertically arranged on the first steel frame 13.

[0051] In this embodiment, the movable steel frame 14 is preferably connected to the first steel frame 13 through a square steel pipe 16, the square steel pipe 16 is fixedly connected to the movable steel frame 14, the cross section of the square steel pipe 16 is rectangular, the square steel pipe 16 is located at the end of the movable steel frame 14 close to the first steel frame 13, the square steel pipe 16 and the movable steel frame 14 can be integrally formed, the square steel pipe 16 is provided with a plurality of bolt holes along the length direction, and the bolt holes on the square steel pipe 16 are used to be bolted to the mounting holes on the first steel frame 13. By adjusting the mounting position of the square steel pipe 16 on the first steel frame 13, the inclination angle of the movable steel frame 14 is adjusted.

[0052] In one embodiment, a first water tank 17 is provided downstream of the test pipe 1. The first water tank 17 is connected to the erosion water tank 5 through a first water pump 18. The first water pump 18 can absorb water from the first water tank 17 and pump it into the erosion water tank 5 to replenish the erosion water tank 5. A water outlet pipe 19 is provided on the side of the erosion water tank 5. The erosion water tank 5 is connected to the first water tank through the water outlet pipe 19. The excess water in the erosion water tank 5 can flow into the first water tank through the water outlet pipe 19. The tail end of the test pipe 1 is connected to the electromagnetic flowmeter 11 through the second hose 20. Preferably, when the test pipe 1 is a rectangular pipe, the rectangular pipe is connected to the second hose 20 through the second square-to-round joint 31. The water outlet end of the electromagnetic flowmeter 11 is connected to the electric regulating valve 10, and the water outlet end of the electric regulating valve 10 is connected to the first water tank through a water pipe. Then, the water flow in the test pipeline 1 can be discharged into the first water storage tank 17 through the electromagnetic flowmeter 11 and the electric regulating valve 10 .

[0053] In one embodiment, the test pipe 1 and the guide cylinder 8 are both made of transparent acrylic material, which is convenient for observation and convenient for the detection optical fiber penetration of the detection member 3. The detection member 3 is preferably a laser sensor. Preferably, laser sensors are installed on both sides of the test pipe 1, and the laser path of the laser sensor is close to the inner surface of the test pipe 1. The height of the test piece can be monitored in real time through the laser sensor. The monitoring and control of the test piece lifting process are realized by the laser sensor, PLC and linear rack motor. Preferably, the laser sensor is an NPN normally open laser sensor, which outputs a negative voltage signal when the laser sensor detects an object, and the linear rack motor used can move a fixed distance through precise control according to the received pulse signal. The output signal of the laser sensor is connected to the input port of the PLC. Under normal conditions, the PLC receives the negative voltage signal of the laser sensor. When the height of the test piece is eroded to be lower than the inner surface of the rectangular pipe, the laser sensor is connected and stops outputting the negative voltage signal. The PLC detects the signal change of the laser sensor and outputs a pulse signal according to the preset program. The output port of the PLC is connected to the control port of the linear rack motor driver. The linear rack motor controls the moving distance of the rack by receiving the pulse signal of the PLC. The moving distance is determined by the number of pulse signals. The distance of the motor rack movement is controlled by adjusting the number of pulses, thereby getting rid of the subjective factors of human visual inspection and realizing quantitative automatic control.

[0054] In one embodiment, the device for simulating soil erosion when the seawall is overrun by waves also includes a seepage simulation device, which includes a pressure water tank 21, a second water pump 22 and a second linear guide rail 25. The second linear guide rail 25 is arranged on a second steel frame 26. The height of the pressure water tank 21 is higher than the test pipe 1. A small hole is opened on the lifting piston 7. The pressure water tank 21 is connected to the small hole on the lifting piston 7 through a hose. In addition, a small hole can be opened on the guide cylinder 8, and the pressure water tank 21 is connected to the small hole on the guide cylinder 8 through a hose; so that the water flowing out of the pressure water tank 21 can act on the test piece. Preferably, the pressure water tank 21 is connected to the guide cylinder 8 through a third hose, and preferably drips directly on the surface of the actual test piece, that is, the pressure water tank 21 can apply a seepage hydraulic gradient to the test piece on the jacking piston 7 through the hose, and the water inlet end of the second water pump 22 is connected to the second water reservoir 27, and water is continuously supplied to the pressure water tank 21 through the second water pump 22. The second water pump 22 is preferably a micro water pump, and the side wall of the pressure water tank 21 is connected to the second water reservoir 27 through a drain pipe. Excess water in the pressure water tank 21 can be discharged into the second water reservoir 27, and the second water reservoir 27 is fixed on the slide of the second linear guide 25, and the slide can reciprocate along the second linear guide 25 driven by the motor. The steel cable of the winch 28 is pulled by the first pulley 24 and the second pulley 29 to control the sliding table on the second linear guide rail 25 to move up and down and suspend. The reciprocating motion of the sliding table of the second linear guide rail 25 is controlled by programming of the single-axis controller to adjust the height of the pressure water tank 21 and apply a constant or variable seepage hydraulic gradient to the test piece. Preferably, before the test piece enters the test pipe 1 for erosion operation, a seepage test is first performed on the test piece. This is because when the seawall is flooded by seawater, a seepage field will be generated on the embankment body, and the seepage field can be simulated through the seepage test.

[0055] Embodiment 2:

[0056] This embodiment provides a simulation method for simulating soil erosion when seawalls are overtopping, including the device for simulating soil erosion when seawalls are overtopping in embodiment 1, and comprising the following steps:

[0057] S1: Adjust the position of the movable steel frame 14 on the first steel frame 13, check the instruments of the erosion test device, including the laser sensor, the linear rack motor, the electromagnetic flowmeter 11, the electric regulating valve 10, the first linear guide rail and the second linear guide rail 25, and check whether the instruments are firmly installed, whether the pipelines are sealed, and whether the circuits are safely connected;

[0058] S2: Apply vaseline or silicone grease evenly on the inner wall of the specimen tube, install the specimen into the guide tube 8 so that the specimen is flush with the top of the guide tube 8, apply vaseline or silicone grease evenly on the rubber ring of the lifting piston 7, insert the lifting piston 7 into the guide tube 8, and make the specimen installation position of the lifting piston 7 fit with the bottom of the specimen.

[0059] S3: Install the guide cylinder 8 at the test piece entrance of the rectangular pipe, and fasten the guide cylinder 8 and the rectangular pipe with bolts, press the button of the linear rack motor on the electric box to move the rack upward until the rack fits with the lifting piston 7.

[0060] S4: Confirm the operation program of the electric control valve 10 through the computer.

[0061] S5: The equipment is powered on and is in the initial state. The first water pump 18 is turned on to fill the rectangular pipe with water in the erosion water tank 5. The electric regulating valve 10 is closed and the equipment remains stationary for 10-15 minutes.

[0062] S6: Control the linear rack motor to start, the upper limit height is 1mm, the lower limit height is: the test piece is lower than the inner surface of the rectangular pipe, that is, the test piece is lower than the water flow path, so that the lifting piston 7 lifts the test piece upward by 1mm, the equipment is running, and the electric regulating valve 10 is opened. The electric regulating valve 10 starts to control the flow velocity change in the rectangular pipe according to the established program. The laser sensor monitors the erosion height of the test piece (soil sample) in real time. If the part of the test piece higher than the inner surface of the rectangular pipe is washed away, then the test piece will be automatically lifted by 1mm. The time of each lifting of the test piece is recorded in the computer data processing system. The experiment ends automatically after the test piece is lifted a certain number of times (for example, 6 times).

[0063] S7: By obtaining the erosion time and erosion height at different erosion rates, the starting shear stress of the soil is obtained by fitting the erosion rate curve, and then the two parameters of erosion coefficient and exponential coefficient are obtained through the over-shear stress model.

[0064] S8: After the test is completed, the test data will be saved in the computer. The data is the time of each lifting of the linear rack motor 6. The difference between adjacent times is the time required for the current water flow to erode 1 mm of the soil sample. The erosion rate of the current state can be obtained, and the calculation formula is:

[0065]

[0066] Where E is the erosion rate, ΔH is the erosion height, and Δt is the erosion duration. The formula of friction coefficient along the flow and wall shear stress is usually used to calculate the shear stress of water flow, and its expression is:

[0067]

[0068] Where f is the friction coefficient obtained from the Moody diagram, ρ is the water flow density, and u is the average flow velocity of the pipe section. The over-shear stress model is usually used to establish the erosion model, and its expression is:

[0069]

[0070] Where k d is the erosion coefficient, τ is the current water flow shear stress, τ c is the starting shear stress, and a is the exponential coefficient. The starting shear stress is the water shear stress of the soil when it is about to start. There are two methods to determine it. One is to use the water shear stress of the soil at an erosion rate of 3.6 mm / h as the starting shear stress of the soil. The other is to plot the test data into an erosion rate curve and use the water shear stress of the fitted erosion rate curve when the erosion rate is 0 as the starting shear stress of the soil.

[0071] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numerals in the claims should not be regarded as limiting the claims involved.

[0072] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A device for simulating soil erosion during seawall overtopping, characterized in that: include: A test pipe (1), wherein the inner wall surface of the test pipe (1) forms a water flow passage, and a test piece inlet communicating with the water flow passage is provided at the bottom of the test pipe (1); A water supply device (2), wherein a water outlet of the water supply device (2) is connected to the upstream of the water flow path; A test piece lifting device comprises a lifting mechanism (4) for delivering the test piece into the water flow passage, a detection element (3) and a control module; the lifting mechanism (4) is provided with a test piece installation position for installing the test piece, the test piece installation position is embedded in a guide cylinder (8) connected to the test piece passage entrance, the test piece extends into the water flow of the water flow passage as the test piece installation position moves, and the distance that the top of the test piece is higher than the bottom of the water flow passage is the upper limit height; the test pipe (1) is also provided with an electric adjustment control for controlling the flow rate of the water flow passage. The electric regulating valve (10) is located downstream of the test piece inlet; the detection member (3) is used to detect the height of the test piece located in the water flow passage; the control module is used to control the lifting mechanism (4) to drive the test piece installation position to rise when the detection member (3) detects that the height of the test piece reaching the bottom of the water flow passage reaches the lower limit height, so that the distance of the top of the test piece above the bottom of the water flow passage reaches the upper limit height again, and the detection member (3) and the lifting mechanism (4) are both electrically connected to the control module.

2. The device for simulating soil erosion during seawall overtopping according to claim 1, characterized in that: The water supply device (2) comprises an erosion water tank (5) located above the test pipe (1); the erosion water tank (5) is connected to the test pipe (1) via a first hose (15).

3. The device for simulating soil erosion during seawall overtopping according to claim 2, characterized in that: The lifting mechanism (4) comprises a linear motor (6) located below the test pipe (1); the movable end of the linear motor (6) is connected to a lifting piston (7); the test piece mounting position is arranged on the top surface of the lifting piston (7); the guide cylinder (8) is fixedly connected to the test pipe (1); and the lifting piston (7) slides along the inner wall surface of the guide cylinder (8).

4. The device for simulating soil erosion during seawall overtopping according to claim 3, characterized in that: The test pipe (1) is a rectangular pipe, and the guide tube (8) is fixed to the lower side of the rectangular pipe; the outer wall surface of the guide tube (8) is sleeved with a sealing plate (9), the sealing plate (9) is sealedly connected to the outer wall surface of the guide tube (8), and the upper surface of the sealing plate (9) is sealedly fitted to the lower side of the rectangular pipe.

5. The device for simulating soil erosion during seawall overtopping according to claim 4, characterized in that: An electromagnetic flowmeter (11) for detecting the flow rate in the water flow passage is also provided in the water flow passage, and the electromagnetic flowmeter (11) and the electric regulating valve (10) are both connected to the control module.

6. The device for simulating soil erosion during seawall overtopping according to claim 5, characterized in that: The invention also comprises an angle adjustment mechanism for adjusting the inclination angle of the test pipeline (1), wherein the angle adjustment mechanism comprises a base steel frame (12), a first steel frame (13) and a movable steel frame (14); one end of the movable steel frame (14) is hinged to the base steel frame (12), the first steel frame (13) is provided with a plurality of mounting holes along the height direction, and the other end of the movable steel frame (14) is bolted to the mounting holes on the first steel frame; the test pipeline (1) is fixedly connected to the movable steel frame (14), the erosion water tank (5) is connected to the first steel frame (13), and the detection member (3) and the lifting mechanism (4) are both arranged on the movable steel frame (14).

7. The device for simulating soil erosion during seawall overtopping according to claim 6, characterized in that: The downstream of the test pipeline (1) is also connected to a first water tank (17), and the first water tank (17) is connected to the erosion water tank (5) through a first water pump (18).

8. The device for simulating soil erosion during seawall overtopping according to claim 7, characterized in that: The invention also comprises a seepage simulation device, wherein the seepage simulation device comprises a pressure water tank (21) and a second steel frame (26), wherein the pressure water tank (21) is slidably connected to the second steel frame (26), a second water storage tank (27) is connected to the second steel frame (26), a water inlet end of the pressure water tank (21) is connected to the second water storage tank (27) via a second water pump (22), and a water outlet end of the pressure water tank (21) is connected to the guide cylinder (8).

9. A simulation method using the device for simulating soil erosion during seawall overtopping as claimed in any one of claims 1 to 8, characterized in that: include: S1, placing the test piece in the test piece installation position on the lifting mechanism (4); S2, opening the water supply device (2), injecting water into the water flow path and closing the electric regulating valve (10), so that the water flow in the water flow path is stationary for a certain period of time; S3, controlling the lifting mechanism (4) to move upward, the lifting mechanism (4) drives the test piece located at the test piece installation position to move upward, and a part of the main body of the test piece extends into the water flow path in the test pipe (1), until the top of the test piece reaches the upper limit height or is higher than the upper limit height; S4, opening the electric regulating valve (10), allowing the water flow to erode the test piece in the water flow passage; and detecting the height of the test piece in the water flow passage in real time by using the detection element (3); S5, when the test piece is lower than or reaches the lower limit height, the erosion of the test piece in the water flow passage is completed, the test piece is lower than the inner wall surface of the test pipe (1), the lifting mechanism (4) drives the test piece to rise, so that the test piece can be passed into the water flow passage again, and the time of each lifting of the test piece is recorded and transmitted to the computer data processing system; S6. The test is terminated after the test piece is lifted a certain number of times.

10. The simulation method according to claim 9, characterized in that: In step S2, the rest time is 10-15 minutes.

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